Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * fs/dcache.c |
| 3 | * |
| 4 | * Complete reimplementation |
| 5 | * (C) 1997 Thomas Schoebel-Theuer, |
| 6 | * with heavy changes by Linus Torvalds |
| 7 | */ |
| 8 | |
| 9 | /* |
| 10 | * Notes on the allocation strategy: |
| 11 | * |
| 12 | * The dcache is a master of the icache - whenever a dcache entry |
| 13 | * exists, the inode will always exist. "iput()" is done either when |
| 14 | * the dcache entry is deleted or garbage collected. |
| 15 | */ |
| 16 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/syscalls.h> |
| 18 | #include <linux/string.h> |
| 19 | #include <linux/mm.h> |
| 20 | #include <linux/fs.h> |
John McCutchan | 7a91bf7 | 2005-08-08 13:52:16 -0400 | [diff] [blame] | 21 | #include <linux/fsnotify.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | #include <linux/slab.h> |
| 23 | #include <linux/init.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include <linux/hash.h> |
| 25 | #include <linux/cache.h> |
Paul Gortmaker | 630d9c4 | 2011-11-16 23:57:37 -0500 | [diff] [blame] | 26 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/mount.h> |
| 28 | #include <linux/file.h> |
| 29 | #include <asm/uaccess.h> |
| 30 | #include <linux/security.h> |
| 31 | #include <linux/seqlock.h> |
| 32 | #include <linux/swap.h> |
| 33 | #include <linux/bootmem.h> |
Al Viro | 5ad4e53 | 2009-03-29 19:50:06 -0400 | [diff] [blame] | 34 | #include <linux/fs_struct.h> |
Frederic Weisbecker | 613afbf | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 35 | #include <linux/hardirq.h> |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 36 | #include <linux/bit_spinlock.h> |
| 37 | #include <linux/rculist_bl.h> |
Linus Torvalds | 268bb0c | 2011-05-20 12:50:29 -0700 | [diff] [blame] | 38 | #include <linux/prefetch.h> |
David Howells | dd17994 | 2011-08-16 15:31:30 +0100 | [diff] [blame] | 39 | #include <linux/ratelimit.h> |
David Howells | 07f3f05 | 2006-09-30 20:52:18 +0200 | [diff] [blame] | 40 | #include "internal.h" |
Al Viro | b2dba1a | 2011-11-23 19:26:23 -0500 | [diff] [blame] | 41 | #include "mount.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 43 | /* |
| 44 | * Usage: |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 45 | * dcache->d_inode->i_lock protects: |
| 46 | * - i_dentry, d_alias, d_inode of aliases |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 47 | * dcache_hash_bucket lock protects: |
| 48 | * - the dcache hash table |
| 49 | * s_anon bl list spinlock protects: |
| 50 | * - the s_anon list (see __d_drop) |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 51 | * dcache_lru_lock protects: |
| 52 | * - the dcache lru lists and counters |
| 53 | * d_lock protects: |
| 54 | * - d_flags |
| 55 | * - d_name |
| 56 | * - d_lru |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 57 | * - d_count |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 58 | * - d_unhashed() |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 59 | * - d_parent and d_subdirs |
| 60 | * - childrens' d_child and d_parent |
Nick Piggin | b23fb0a | 2011-01-07 17:49:35 +1100 | [diff] [blame] | 61 | * - d_alias, d_inode |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 62 | * |
| 63 | * Ordering: |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 64 | * dentry->d_inode->i_lock |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 65 | * dentry->d_lock |
| 66 | * dcache_lru_lock |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 67 | * dcache_hash_bucket lock |
| 68 | * s_anon lock |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 69 | * |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 70 | * If there is an ancestor relationship: |
| 71 | * dentry->d_parent->...->d_parent->d_lock |
| 72 | * ... |
| 73 | * dentry->d_parent->d_lock |
| 74 | * dentry->d_lock |
| 75 | * |
| 76 | * If no ancestor relationship: |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 77 | * if (dentry1 < dentry2) |
| 78 | * dentry1->d_lock |
| 79 | * dentry2->d_lock |
| 80 | */ |
Eric Dumazet | fa3536c | 2006-03-26 01:37:24 -0800 | [diff] [blame] | 81 | int sysctl_vfs_cache_pressure __read_mostly = 100; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure); |
| 83 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 84 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lru_lock); |
Al Viro | 74c3cbe | 2007-07-22 08:04:18 -0400 | [diff] [blame] | 85 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 87 | EXPORT_SYMBOL(rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 89 | static struct kmem_cache *dentry_cache __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | /* |
| 92 | * This is the single most critical data structure when it comes |
| 93 | * to the dcache: the hashtable for lookups. Somebody should try |
| 94 | * to make this good - I've just made it work. |
| 95 | * |
| 96 | * This hash-function tries to avoid losing too many bits of hash |
| 97 | * information, yet avoid using a prime hash-size or similar. |
| 98 | */ |
| 99 | #define D_HASHBITS d_hash_shift |
| 100 | #define D_HASHMASK d_hash_mask |
| 101 | |
Eric Dumazet | fa3536c | 2006-03-26 01:37:24 -0800 | [diff] [blame] | 102 | static unsigned int d_hash_mask __read_mostly; |
| 103 | static unsigned int d_hash_shift __read_mostly; |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 104 | |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 105 | static struct hlist_bl_head *dentry_hashtable __read_mostly; |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 106 | |
Linus Torvalds | 8966be9 | 2012-03-02 14:23:30 -0800 | [diff] [blame] | 107 | static inline struct hlist_bl_head *d_hash(const struct dentry *parent, |
Linus Torvalds | 6d7d1a0 | 2012-03-19 16:19:53 -0700 | [diff] [blame] | 108 | unsigned int hash) |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 109 | { |
Linus Torvalds | 6d7d1a0 | 2012-03-19 16:19:53 -0700 | [diff] [blame] | 110 | hash += (unsigned long) parent / L1_CACHE_BYTES; |
| 111 | hash = hash + (hash >> D_HASHBITS); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 112 | return dentry_hashtable + (hash & D_HASHMASK); |
| 113 | } |
| 114 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | /* Statistics gathering. */ |
| 116 | struct dentry_stat_t dentry_stat = { |
| 117 | .age_limit = 45, |
| 118 | }; |
| 119 | |
Nick Piggin | 3e880fb | 2011-01-07 17:49:19 +1100 | [diff] [blame] | 120 | static DEFINE_PER_CPU(unsigned int, nr_dentry); |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 121 | |
| 122 | #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS) |
Nick Piggin | 3e880fb | 2011-01-07 17:49:19 +1100 | [diff] [blame] | 123 | static int get_nr_dentry(void) |
| 124 | { |
| 125 | int i; |
| 126 | int sum = 0; |
| 127 | for_each_possible_cpu(i) |
| 128 | sum += per_cpu(nr_dentry, i); |
| 129 | return sum < 0 ? 0 : sum; |
| 130 | } |
| 131 | |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 132 | int proc_nr_dentry(ctl_table *table, int write, void __user *buffer, |
| 133 | size_t *lenp, loff_t *ppos) |
| 134 | { |
Nick Piggin | 3e880fb | 2011-01-07 17:49:19 +1100 | [diff] [blame] | 135 | dentry_stat.nr_dentry = get_nr_dentry(); |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 136 | return proc_dointvec(table, write, buffer, lenp, ppos); |
| 137 | } |
| 138 | #endif |
| 139 | |
Linus Torvalds | 5483f18 | 2012-03-04 15:51:42 -0800 | [diff] [blame] | 140 | /* |
| 141 | * Compare 2 name strings, return 0 if they match, otherwise non-zero. |
| 142 | * The strings are both count bytes long, and count is non-zero. |
| 143 | */ |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 144 | #ifdef CONFIG_DCACHE_WORD_ACCESS |
| 145 | |
| 146 | #include <asm/word-at-a-time.h> |
| 147 | /* |
| 148 | * NOTE! 'cs' and 'scount' come from a dentry, so it has a |
| 149 | * aligned allocation for this particular component. We don't |
| 150 | * strictly need the load_unaligned_zeropad() safety, but it |
| 151 | * doesn't hurt either. |
| 152 | * |
| 153 | * In contrast, 'ct' and 'tcount' can be from a pathname, and do |
| 154 | * need the careful unaligned handling. |
| 155 | */ |
Linus Torvalds | 94753db5 | 2012-05-10 12:19:19 -0700 | [diff] [blame] | 156 | static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount) |
Linus Torvalds | 5483f18 | 2012-03-04 15:51:42 -0800 | [diff] [blame] | 157 | { |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 158 | unsigned long a,b,mask; |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 159 | |
| 160 | for (;;) { |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 161 | a = *(unsigned long *)cs; |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 162 | b = load_unaligned_zeropad(ct); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 163 | if (tcount < sizeof(unsigned long)) |
| 164 | break; |
| 165 | if (unlikely(a != b)) |
| 166 | return 1; |
| 167 | cs += sizeof(unsigned long); |
| 168 | ct += sizeof(unsigned long); |
| 169 | tcount -= sizeof(unsigned long); |
| 170 | if (!tcount) |
| 171 | return 0; |
| 172 | } |
| 173 | mask = ~(~0ul << tcount*8); |
| 174 | return unlikely(!!((a ^ b) & mask)); |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 175 | } |
| 176 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 177 | #else |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 178 | |
Linus Torvalds | 94753db5 | 2012-05-10 12:19:19 -0700 | [diff] [blame] | 179 | static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount) |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 180 | { |
Linus Torvalds | 5483f18 | 2012-03-04 15:51:42 -0800 | [diff] [blame] | 181 | do { |
| 182 | if (*cs != *ct) |
| 183 | return 1; |
| 184 | cs++; |
| 185 | ct++; |
| 186 | tcount--; |
| 187 | } while (tcount); |
| 188 | return 0; |
| 189 | } |
| 190 | |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 191 | #endif |
| 192 | |
Linus Torvalds | 94753db5 | 2012-05-10 12:19:19 -0700 | [diff] [blame] | 193 | static inline int dentry_cmp(const struct dentry *dentry, const unsigned char *ct, unsigned tcount) |
| 194 | { |
Linus Torvalds | 6326c71 | 2012-05-21 16:14:04 -0700 | [diff] [blame] | 195 | const unsigned char *cs; |
Linus Torvalds | 94753db5 | 2012-05-10 12:19:19 -0700 | [diff] [blame] | 196 | /* |
| 197 | * Be careful about RCU walk racing with rename: |
| 198 | * use ACCESS_ONCE to fetch the name pointer. |
| 199 | * |
| 200 | * NOTE! Even if a rename will mean that the length |
| 201 | * was not loaded atomically, we don't care. The |
| 202 | * RCU walk will check the sequence count eventually, |
| 203 | * and catch it. And we won't overrun the buffer, |
| 204 | * because we're reading the name pointer atomically, |
| 205 | * and a dentry name is guaranteed to be properly |
| 206 | * terminated with a NUL byte. |
| 207 | * |
| 208 | * End result: even if 'len' is wrong, we'll exit |
| 209 | * early because the data cannot match (there can |
| 210 | * be no NUL in the ct/tcount data) |
| 211 | */ |
Linus Torvalds | 6326c71 | 2012-05-21 16:14:04 -0700 | [diff] [blame] | 212 | cs = ACCESS_ONCE(dentry->d_name.name); |
| 213 | smp_read_barrier_depends(); |
| 214 | return dentry_string_cmp(cs, ct, tcount); |
Linus Torvalds | 94753db5 | 2012-05-10 12:19:19 -0700 | [diff] [blame] | 215 | } |
| 216 | |
Christoph Hellwig | 9c82ab9 | 2010-10-10 05:36:22 -0400 | [diff] [blame] | 217 | static void __d_free(struct rcu_head *head) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | { |
Christoph Hellwig | 9c82ab9 | 2010-10-10 05:36:22 -0400 | [diff] [blame] | 219 | struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); |
| 220 | |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 221 | WARN_ON(!hlist_unhashed(&dentry->d_alias)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | if (dname_external(dentry)) |
| 223 | kfree(dentry->d_name.name); |
| 224 | kmem_cache_free(dentry_cache, dentry); |
| 225 | } |
| 226 | |
| 227 | /* |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 228 | * no locks, please. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | */ |
| 230 | static void d_free(struct dentry *dentry) |
| 231 | { |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 232 | BUG_ON(dentry->d_lockref.count); |
Nick Piggin | 3e880fb | 2011-01-07 17:49:19 +1100 | [diff] [blame] | 233 | this_cpu_dec(nr_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 234 | if (dentry->d_op && dentry->d_op->d_release) |
| 235 | dentry->d_op->d_release(dentry); |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 236 | |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 237 | /* if dentry was never visible to RCU, immediate free is OK */ |
| 238 | if (!(dentry->d_flags & DCACHE_RCUACCESS)) |
Christoph Hellwig | 9c82ab9 | 2010-10-10 05:36:22 -0400 | [diff] [blame] | 239 | __d_free(&dentry->d_u.d_rcu); |
Eric Dumazet | b342341 | 2006-12-06 20:38:48 -0800 | [diff] [blame] | 240 | else |
Christoph Hellwig | 9c82ab9 | 2010-10-10 05:36:22 -0400 | [diff] [blame] | 241 | call_rcu(&dentry->d_u.d_rcu, __d_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | } |
| 243 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 244 | /** |
| 245 | * dentry_rcuwalk_barrier - invalidate in-progress rcu-walk lookups |
Randy Dunlap | ff5fdb6 | 2011-01-22 20:16:06 -0800 | [diff] [blame] | 246 | * @dentry: the target dentry |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 247 | * After this call, in-progress rcu-walk path lookup will fail. This |
| 248 | * should be called after unhashing, and after changing d_inode (if |
| 249 | * the dentry has not already been unhashed). |
| 250 | */ |
| 251 | static inline void dentry_rcuwalk_barrier(struct dentry *dentry) |
| 252 | { |
| 253 | assert_spin_locked(&dentry->d_lock); |
| 254 | /* Go through a barrier */ |
| 255 | write_seqcount_barrier(&dentry->d_seq); |
| 256 | } |
| 257 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | /* |
| 259 | * Release the dentry's inode, using the filesystem |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 260 | * d_iput() operation if defined. Dentry has no refcount |
| 261 | * and is unhashed. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 263 | static void dentry_iput(struct dentry * dentry) |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 264 | __releases(dentry->d_lock) |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 265 | __releases(dentry->d_inode->i_lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 266 | { |
| 267 | struct inode *inode = dentry->d_inode; |
| 268 | if (inode) { |
| 269 | dentry->d_inode = NULL; |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 270 | hlist_del_init(&dentry->d_alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 272 | spin_unlock(&inode->i_lock); |
Linus Torvalds | f805fbd | 2005-09-19 19:54:29 -0700 | [diff] [blame] | 273 | if (!inode->i_nlink) |
| 274 | fsnotify_inoderemove(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | if (dentry->d_op && dentry->d_op->d_iput) |
| 276 | dentry->d_op->d_iput(dentry, inode); |
| 277 | else |
| 278 | iput(inode); |
| 279 | } else { |
| 280 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | } |
| 282 | } |
| 283 | |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 284 | /* |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 285 | * Release the dentry's inode, using the filesystem |
| 286 | * d_iput() operation if defined. dentry remains in-use. |
| 287 | */ |
| 288 | static void dentry_unlink_inode(struct dentry * dentry) |
| 289 | __releases(dentry->d_lock) |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 290 | __releases(dentry->d_inode->i_lock) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 291 | { |
| 292 | struct inode *inode = dentry->d_inode; |
| 293 | dentry->d_inode = NULL; |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 294 | hlist_del_init(&dentry->d_alias); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 295 | dentry_rcuwalk_barrier(dentry); |
| 296 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 297 | spin_unlock(&inode->i_lock); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 298 | if (!inode->i_nlink) |
| 299 | fsnotify_inoderemove(inode); |
| 300 | if (dentry->d_op && dentry->d_op->d_iput) |
| 301 | dentry->d_op->d_iput(dentry, inode); |
| 302 | else |
| 303 | iput(inode); |
| 304 | } |
| 305 | |
| 306 | /* |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 307 | * dentry_lru_(add|del|prune|move_tail) must be called with d_lock held. |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 308 | */ |
| 309 | static void dentry_lru_add(struct dentry *dentry) |
| 310 | { |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 311 | if (list_empty(&dentry->d_lru)) { |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 312 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 313 | list_add(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); |
| 314 | dentry->d_sb->s_nr_dentry_unused++; |
Nick Piggin | 86c8749 | 2011-01-07 17:49:18 +1100 | [diff] [blame] | 315 | dentry_stat.nr_unused++; |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 316 | spin_unlock(&dcache_lru_lock); |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 317 | } |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 318 | } |
| 319 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 320 | static void __dentry_lru_del(struct dentry *dentry) |
| 321 | { |
| 322 | list_del_init(&dentry->d_lru); |
Miklos Szeredi | eaf5f90 | 2012-01-10 18:22:25 +0100 | [diff] [blame] | 323 | dentry->d_flags &= ~DCACHE_SHRINK_LIST; |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 324 | dentry->d_sb->s_nr_dentry_unused--; |
| 325 | dentry_stat.nr_unused--; |
| 326 | } |
| 327 | |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 328 | /* |
| 329 | * Remove a dentry with references from the LRU. |
| 330 | */ |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 331 | static void dentry_lru_del(struct dentry *dentry) |
| 332 | { |
| 333 | if (!list_empty(&dentry->d_lru)) { |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 334 | spin_lock(&dcache_lru_lock); |
| 335 | __dentry_lru_del(dentry); |
| 336 | spin_unlock(&dcache_lru_lock); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 337 | } |
| 338 | } |
| 339 | |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 340 | static void dentry_lru_move_list(struct dentry *dentry, struct list_head *list) |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 341 | { |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 342 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 343 | if (list_empty(&dentry->d_lru)) { |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 344 | list_add_tail(&dentry->d_lru, list); |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 345 | dentry->d_sb->s_nr_dentry_unused++; |
Nick Piggin | 86c8749 | 2011-01-07 17:49:18 +1100 | [diff] [blame] | 346 | dentry_stat.nr_unused++; |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 347 | } else { |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 348 | list_move_tail(&dentry->d_lru, list); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 349 | } |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 350 | spin_unlock(&dcache_lru_lock); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 351 | } |
| 352 | |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 353 | /** |
| 354 | * d_kill - kill dentry and return parent |
| 355 | * @dentry: dentry to kill |
Randy Dunlap | ff5fdb6 | 2011-01-22 20:16:06 -0800 | [diff] [blame] | 356 | * @parent: parent dentry |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 357 | * |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 358 | * The dentry must already be unhashed and removed from the LRU. |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 359 | * |
| 360 | * If this is the root of the dentry tree, return NULL. |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 361 | * |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 362 | * dentry->d_lock and parent->d_lock must be held by caller, and are dropped by |
| 363 | * d_kill. |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 364 | */ |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 365 | static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent) |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 366 | __releases(dentry->d_lock) |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 367 | __releases(parent->d_lock) |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 368 | __releases(dentry->d_inode->i_lock) |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 369 | { |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 370 | list_del(&dentry->d_u.d_child); |
Trond Myklebust | c83ce98 | 2011-03-15 13:36:43 -0400 | [diff] [blame] | 371 | /* |
| 372 | * Inform try_to_ascend() that we are no longer attached to the |
| 373 | * dentry tree |
| 374 | */ |
Miklos Szeredi | b161dfa6 | 2012-09-17 22:31:38 +0200 | [diff] [blame] | 375 | dentry->d_flags |= DCACHE_DENTRY_KILLED; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 376 | if (parent) |
| 377 | spin_unlock(&parent->d_lock); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 378 | dentry_iput(dentry); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 379 | /* |
| 380 | * dentry_iput drops the locks, at which point nobody (except |
| 381 | * transient RCU lookups) can reach this dentry. |
| 382 | */ |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 383 | d_free(dentry); |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 384 | return parent; |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 385 | } |
| 386 | |
David Howells | c6627c6 | 2011-06-07 14:09:20 +0100 | [diff] [blame] | 387 | /* |
| 388 | * Unhash a dentry without inserting an RCU walk barrier or checking that |
| 389 | * dentry->d_lock is locked. The caller must take care of that, if |
| 390 | * appropriate. |
| 391 | */ |
| 392 | static void __d_shrink(struct dentry *dentry) |
| 393 | { |
| 394 | if (!d_unhashed(dentry)) { |
| 395 | struct hlist_bl_head *b; |
| 396 | if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) |
| 397 | b = &dentry->d_sb->s_anon; |
| 398 | else |
| 399 | b = d_hash(dentry->d_parent, dentry->d_name.hash); |
| 400 | |
| 401 | hlist_bl_lock(b); |
| 402 | __hlist_bl_del(&dentry->d_hash); |
| 403 | dentry->d_hash.pprev = NULL; |
| 404 | hlist_bl_unlock(b); |
| 405 | } |
| 406 | } |
| 407 | |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 408 | /** |
| 409 | * d_drop - drop a dentry |
| 410 | * @dentry: dentry to drop |
| 411 | * |
| 412 | * d_drop() unhashes the entry from the parent dentry hashes, so that it won't |
| 413 | * be found through a VFS lookup any more. Note that this is different from |
| 414 | * deleting the dentry - d_delete will try to mark the dentry negative if |
| 415 | * possible, giving a successful _negative_ lookup, while d_drop will |
| 416 | * just make the cache lookup fail. |
| 417 | * |
| 418 | * d_drop() is used mainly for stuff that wants to invalidate a dentry for some |
| 419 | * reason (NFS timeouts or autofs deletes). |
| 420 | * |
| 421 | * __d_drop requires dentry->d_lock. |
| 422 | */ |
| 423 | void __d_drop(struct dentry *dentry) |
| 424 | { |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 425 | if (!d_unhashed(dentry)) { |
David Howells | c6627c6 | 2011-06-07 14:09:20 +0100 | [diff] [blame] | 426 | __d_shrink(dentry); |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 427 | dentry_rcuwalk_barrier(dentry); |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 428 | } |
| 429 | } |
| 430 | EXPORT_SYMBOL(__d_drop); |
| 431 | |
| 432 | void d_drop(struct dentry *dentry) |
| 433 | { |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 434 | spin_lock(&dentry->d_lock); |
| 435 | __d_drop(dentry); |
| 436 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 437 | } |
| 438 | EXPORT_SYMBOL(d_drop); |
| 439 | |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 440 | /* |
| 441 | * Finish off a dentry we've decided to kill. |
| 442 | * dentry->d_lock must be held, returns with it unlocked. |
| 443 | * If ref is non-zero, then decrement the refcount too. |
| 444 | * Returns dentry requiring refcount drop, or NULL if we're done. |
| 445 | */ |
| 446 | static inline struct dentry *dentry_kill(struct dentry *dentry, int ref) |
| 447 | __releases(dentry->d_lock) |
| 448 | { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 449 | struct inode *inode; |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 450 | struct dentry *parent; |
| 451 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 452 | inode = dentry->d_inode; |
| 453 | if (inode && !spin_trylock(&inode->i_lock)) { |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 454 | relock: |
| 455 | spin_unlock(&dentry->d_lock); |
| 456 | cpu_relax(); |
| 457 | return dentry; /* try again with same dentry */ |
| 458 | } |
| 459 | if (IS_ROOT(dentry)) |
| 460 | parent = NULL; |
| 461 | else |
| 462 | parent = dentry->d_parent; |
| 463 | if (parent && !spin_trylock(&parent->d_lock)) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 464 | if (inode) |
| 465 | spin_unlock(&inode->i_lock); |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 466 | goto relock; |
| 467 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 468 | |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 469 | if (ref) |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 470 | dentry->d_lockref.count--; |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 471 | /* |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 472 | * inform the fs via d_prune that this dentry is about to be |
| 473 | * unhashed and destroyed. |
| 474 | */ |
Yan, Zheng | 61572bb | 2013-04-15 14:13:21 +0800 | [diff] [blame] | 475 | if (dentry->d_flags & DCACHE_OP_PRUNE) |
| 476 | dentry->d_op->d_prune(dentry); |
| 477 | |
| 478 | dentry_lru_del(dentry); |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 479 | /* if it was on the hash then remove it */ |
| 480 | __d_drop(dentry); |
| 481 | return d_kill(dentry, parent); |
| 482 | } |
| 483 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 484 | /* |
| 485 | * This is dput |
| 486 | * |
| 487 | * This is complicated by the fact that we do not want to put |
| 488 | * dentries that are no longer on any hash chain on the unused |
| 489 | * list: we'd much rather just get rid of them immediately. |
| 490 | * |
| 491 | * However, that implies that we have to traverse the dentry |
| 492 | * tree upwards to the parents which might _also_ now be |
| 493 | * scheduled for deletion (it may have been only waiting for |
| 494 | * its last child to go away). |
| 495 | * |
| 496 | * This tail recursion is done by hand as we don't want to depend |
| 497 | * on the compiler to always get this right (gcc generally doesn't). |
| 498 | * Real recursion would eat up our stack space. |
| 499 | */ |
| 500 | |
| 501 | /* |
| 502 | * dput - release a dentry |
| 503 | * @dentry: dentry to release |
| 504 | * |
| 505 | * Release a dentry. This will drop the usage count and if appropriate |
| 506 | * call the dentry unlink method as well as removing it from the queues and |
| 507 | * releasing its resources. If the parent dentries were scheduled for release |
| 508 | * they too may now get deleted. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | void dput(struct dentry *dentry) |
| 511 | { |
| 512 | if (!dentry) |
| 513 | return; |
| 514 | |
| 515 | repeat: |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 516 | if (dentry->d_lockref.count == 1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 517 | might_sleep(); |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 518 | if (lockref_put_or_lock(&dentry->d_lockref)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 519 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 520 | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 521 | if (dentry->d_flags & DCACHE_OP_DELETE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | if (dentry->d_op->d_delete(dentry)) |
Nick Piggin | 61f3dee | 2011-01-07 17:49:40 +1100 | [diff] [blame] | 523 | goto kill_it; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 524 | } |
Nick Piggin | 265ac90 | 2010-10-10 05:36:24 -0400 | [diff] [blame] | 525 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | /* Unreachable? Get rid of it */ |
| 527 | if (d_unhashed(dentry)) |
| 528 | goto kill_it; |
Nick Piggin | 265ac90 | 2010-10-10 05:36:24 -0400 | [diff] [blame] | 529 | |
Jeff Layton | 39e3c95 | 2012-11-28 11:30:53 -0500 | [diff] [blame] | 530 | dentry->d_flags |= DCACHE_REFERENCED; |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 531 | dentry_lru_add(dentry); |
Nick Piggin | 265ac90 | 2010-10-10 05:36:24 -0400 | [diff] [blame] | 532 | |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 533 | dentry->d_lockref.count--; |
Nick Piggin | 61f3dee | 2011-01-07 17:49:40 +1100 | [diff] [blame] | 534 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | return; |
| 536 | |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 537 | kill_it: |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 538 | dentry = dentry_kill(dentry, 1); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 539 | if (dentry) |
| 540 | goto repeat; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 541 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 542 | EXPORT_SYMBOL(dput); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 543 | |
| 544 | /** |
| 545 | * d_invalidate - invalidate a dentry |
| 546 | * @dentry: dentry to invalidate |
| 547 | * |
| 548 | * Try to invalidate the dentry if it turns out to be |
| 549 | * possible. If there are other dentries that can be |
| 550 | * reached through this one we can't delete it and we |
| 551 | * return -EBUSY. On success we return 0. |
| 552 | * |
| 553 | * no dcache lock. |
| 554 | */ |
| 555 | |
| 556 | int d_invalidate(struct dentry * dentry) |
| 557 | { |
| 558 | /* |
| 559 | * If it's already been dropped, return OK. |
| 560 | */ |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 561 | spin_lock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 562 | if (d_unhashed(dentry)) { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 563 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | return 0; |
| 565 | } |
| 566 | /* |
| 567 | * Check whether to do a partial shrink_dcache |
| 568 | * to get rid of unused child entries. |
| 569 | */ |
| 570 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 571 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 572 | shrink_dcache_parent(dentry); |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 573 | spin_lock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | } |
| 575 | |
| 576 | /* |
| 577 | * Somebody else still using it? |
| 578 | * |
| 579 | * If it's a directory, we can't drop it |
| 580 | * for fear of somebody re-populating it |
| 581 | * with children (even though dropping it |
| 582 | * would make it unreachable from the root, |
| 583 | * we might still populate it if it was a |
| 584 | * working directory or similar). |
Al Viro | 50e6963 | 2011-11-07 16:39:57 +0000 | [diff] [blame] | 585 | * We also need to leave mountpoints alone, |
| 586 | * directory or not. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 587 | */ |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 588 | if (dentry->d_lockref.count > 1 && dentry->d_inode) { |
Al Viro | 50e6963 | 2011-11-07 16:39:57 +0000 | [diff] [blame] | 589 | if (S_ISDIR(dentry->d_inode->i_mode) || d_mountpoint(dentry)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | return -EBUSY; |
| 592 | } |
| 593 | } |
| 594 | |
| 595 | __d_drop(dentry); |
| 596 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 597 | return 0; |
| 598 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 599 | EXPORT_SYMBOL(d_invalidate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 601 | /* This must be called with d_lock held */ |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 602 | static inline void __dget_dlock(struct dentry *dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 603 | { |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 604 | dentry->d_lockref.count++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | } |
| 606 | |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 607 | static inline void __dget(struct dentry *dentry) |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 608 | { |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 609 | lockref_get(&dentry->d_lockref); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 610 | } |
| 611 | |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 612 | struct dentry *dget_parent(struct dentry *dentry) |
| 613 | { |
| 614 | struct dentry *ret; |
| 615 | |
| 616 | repeat: |
Nick Piggin | a734eb4 | 2011-01-07 17:49:44 +1100 | [diff] [blame] | 617 | /* |
| 618 | * Don't need rcu_dereference because we re-check it was correct under |
| 619 | * the lock. |
| 620 | */ |
| 621 | rcu_read_lock(); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 622 | ret = dentry->d_parent; |
Nick Piggin | a734eb4 | 2011-01-07 17:49:44 +1100 | [diff] [blame] | 623 | spin_lock(&ret->d_lock); |
| 624 | if (unlikely(ret != dentry->d_parent)) { |
| 625 | spin_unlock(&ret->d_lock); |
| 626 | rcu_read_unlock(); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 627 | goto repeat; |
| 628 | } |
Nick Piggin | a734eb4 | 2011-01-07 17:49:44 +1100 | [diff] [blame] | 629 | rcu_read_unlock(); |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 630 | BUG_ON(!ret->d_lockref.count); |
| 631 | ret->d_lockref.count++; |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 632 | spin_unlock(&ret->d_lock); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 633 | return ret; |
| 634 | } |
| 635 | EXPORT_SYMBOL(dget_parent); |
| 636 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 637 | /** |
| 638 | * d_find_alias - grab a hashed alias of inode |
| 639 | * @inode: inode in question |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 640 | * @want_discon: flag, used by d_splice_alias, to request |
| 641 | * that only a DISCONNECTED alias be returned. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 642 | * |
| 643 | * If inode has a hashed alias, or is a directory and has any alias, |
| 644 | * acquire the reference to alias and return it. Otherwise return NULL. |
| 645 | * Notice that if inode is a directory there can be only one alias and |
| 646 | * it can be unhashed only if it has no children, or if it is the root |
| 647 | * of a filesystem. |
| 648 | * |
NeilBrown | 21c0d8f | 2006-10-04 02:16:16 -0700 | [diff] [blame] | 649 | * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 650 | * any other hashed alias over that one unless @want_discon is set, |
| 651 | * in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 652 | */ |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 653 | static struct dentry *__d_find_alias(struct inode *inode, int want_discon) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 654 | { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 655 | struct dentry *alias, *discon_alias; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 657 | again: |
| 658 | discon_alias = NULL; |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 659 | hlist_for_each_entry(alias, &inode->i_dentry, d_alias) { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 660 | spin_lock(&alias->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { |
NeilBrown | 21c0d8f | 2006-10-04 02:16:16 -0700 | [diff] [blame] | 662 | if (IS_ROOT(alias) && |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 663 | (alias->d_flags & DCACHE_DISCONNECTED)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | discon_alias = alias; |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 665 | } else if (!want_discon) { |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 666 | __dget_dlock(alias); |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 667 | spin_unlock(&alias->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 668 | return alias; |
| 669 | } |
| 670 | } |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 671 | spin_unlock(&alias->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | } |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 673 | if (discon_alias) { |
| 674 | alias = discon_alias; |
| 675 | spin_lock(&alias->d_lock); |
| 676 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { |
| 677 | if (IS_ROOT(alias) && |
| 678 | (alias->d_flags & DCACHE_DISCONNECTED)) { |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 679 | __dget_dlock(alias); |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 680 | spin_unlock(&alias->d_lock); |
| 681 | return alias; |
| 682 | } |
| 683 | } |
| 684 | spin_unlock(&alias->d_lock); |
| 685 | goto again; |
| 686 | } |
| 687 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 688 | } |
| 689 | |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 690 | struct dentry *d_find_alias(struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 691 | { |
David Howells | 214fda1 | 2006-03-25 03:06:36 -0800 | [diff] [blame] | 692 | struct dentry *de = NULL; |
| 693 | |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 694 | if (!hlist_empty(&inode->i_dentry)) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 695 | spin_lock(&inode->i_lock); |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 696 | de = __d_find_alias(inode, 0); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 697 | spin_unlock(&inode->i_lock); |
David Howells | 214fda1 | 2006-03-25 03:06:36 -0800 | [diff] [blame] | 698 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 699 | return de; |
| 700 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 701 | EXPORT_SYMBOL(d_find_alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 702 | |
| 703 | /* |
| 704 | * Try to kill dentries associated with this inode. |
| 705 | * WARNING: you must own a reference to inode. |
| 706 | */ |
| 707 | void d_prune_aliases(struct inode *inode) |
| 708 | { |
Domen Puncer | 0cdca3f | 2005-09-10 00:27:07 -0700 | [diff] [blame] | 709 | struct dentry *dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 710 | restart: |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 711 | spin_lock(&inode->i_lock); |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 712 | hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 713 | spin_lock(&dentry->d_lock); |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 714 | if (!dentry->d_lockref.count) { |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 715 | __dget_dlock(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 716 | __d_drop(dentry); |
| 717 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 718 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 719 | dput(dentry); |
| 720 | goto restart; |
| 721 | } |
| 722 | spin_unlock(&dentry->d_lock); |
| 723 | } |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 724 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 725 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 726 | EXPORT_SYMBOL(d_prune_aliases); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 727 | |
| 728 | /* |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 729 | * Try to throw away a dentry - free the inode, dput the parent. |
| 730 | * Requires dentry->d_lock is held, and dentry->d_count == 0. |
| 731 | * Releases dentry->d_lock. |
Andrew Morton | d702ccb | 2006-06-22 14:47:31 -0700 | [diff] [blame] | 732 | * |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 733 | * This may fail if locks cannot be acquired no problem, just try again. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 734 | */ |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 735 | static void try_prune_one_dentry(struct dentry *dentry) |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 736 | __releases(dentry->d_lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 737 | { |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 738 | struct dentry *parent; |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 739 | |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 740 | parent = dentry_kill(dentry, 0); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 741 | /* |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 742 | * If dentry_kill returns NULL, we have nothing more to do. |
| 743 | * if it returns the same dentry, trylocks failed. In either |
| 744 | * case, just loop again. |
| 745 | * |
| 746 | * Otherwise, we need to prune ancestors too. This is necessary |
| 747 | * to prevent quadratic behavior of shrink_dcache_parent(), but |
| 748 | * is also expected to be beneficial in reducing dentry cache |
| 749 | * fragmentation. |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 750 | */ |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 751 | if (!parent) |
| 752 | return; |
| 753 | if (parent == dentry) |
| 754 | return; |
| 755 | |
| 756 | /* Prune ancestors. */ |
| 757 | dentry = parent; |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 758 | while (dentry) { |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 759 | if (lockref_put_or_lock(&dentry->d_lockref)) |
Nick Piggin | 89e6054 | 2011-01-07 17:49:45 +1100 | [diff] [blame] | 760 | return; |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 761 | dentry = dentry_kill(dentry, 1); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 762 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 763 | } |
| 764 | |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 765 | static void shrink_dentry_list(struct list_head *list) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 766 | { |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 767 | struct dentry *dentry; |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 768 | |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 769 | rcu_read_lock(); |
| 770 | for (;;) { |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 771 | dentry = list_entry_rcu(list->prev, struct dentry, d_lru); |
| 772 | if (&dentry->d_lru == list) |
| 773 | break; /* empty */ |
| 774 | spin_lock(&dentry->d_lock); |
| 775 | if (dentry != list_entry(list->prev, struct dentry, d_lru)) { |
| 776 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 777 | continue; |
| 778 | } |
| 779 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 780 | /* |
| 781 | * We found an inuse dentry which was not removed from |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 782 | * the LRU because of laziness during lookup. Do not free |
| 783 | * it - just keep it off the LRU list. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 784 | */ |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 785 | if (dentry->d_lockref.count) { |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 786 | dentry_lru_del(dentry); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 787 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 788 | continue; |
| 789 | } |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 790 | |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 791 | rcu_read_unlock(); |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 792 | |
| 793 | try_prune_one_dentry(dentry); |
| 794 | |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 795 | rcu_read_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 796 | } |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 797 | rcu_read_unlock(); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 798 | } |
| 799 | |
| 800 | /** |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 801 | * prune_dcache_sb - shrink the dcache |
| 802 | * @sb: superblock |
| 803 | * @count: number of entries to try to free |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 804 | * |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 805 | * Attempt to shrink the superblock dcache LRU by @count entries. This is |
| 806 | * done when we need more memory an called from the superblock shrinker |
| 807 | * function. |
| 808 | * |
| 809 | * This function may fail to free any resources if all the dentries are in |
| 810 | * use. |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 811 | */ |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 812 | void prune_dcache_sb(struct super_block *sb, int count) |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 813 | { |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 814 | struct dentry *dentry; |
| 815 | LIST_HEAD(referenced); |
| 816 | LIST_HEAD(tmp); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 817 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 818 | relock: |
| 819 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 820 | while (!list_empty(&sb->s_dentry_lru)) { |
| 821 | dentry = list_entry(sb->s_dentry_lru.prev, |
| 822 | struct dentry, d_lru); |
| 823 | BUG_ON(dentry->d_sb != sb); |
| 824 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 825 | if (!spin_trylock(&dentry->d_lock)) { |
| 826 | spin_unlock(&dcache_lru_lock); |
| 827 | cpu_relax(); |
| 828 | goto relock; |
| 829 | } |
| 830 | |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 831 | if (dentry->d_flags & DCACHE_REFERENCED) { |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 832 | dentry->d_flags &= ~DCACHE_REFERENCED; |
| 833 | list_move(&dentry->d_lru, &referenced); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 834 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 835 | } else { |
| 836 | list_move_tail(&dentry->d_lru, &tmp); |
Miklos Szeredi | eaf5f90 | 2012-01-10 18:22:25 +0100 | [diff] [blame] | 837 | dentry->d_flags |= DCACHE_SHRINK_LIST; |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 838 | spin_unlock(&dentry->d_lock); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 839 | if (!--count) |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 840 | break; |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 841 | } |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 842 | cond_resched_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 843 | } |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 844 | if (!list_empty(&referenced)) |
| 845 | list_splice(&referenced, &sb->s_dentry_lru); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 846 | spin_unlock(&dcache_lru_lock); |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 847 | |
| 848 | shrink_dentry_list(&tmp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 849 | } |
| 850 | |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 851 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 852 | * shrink_dcache_sb - shrink dcache for a superblock |
| 853 | * @sb: superblock |
| 854 | * |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 855 | * Shrink the dcache for the specified super block. This is used to free |
| 856 | * the dcache before unmounting a file system. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 857 | */ |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 858 | void shrink_dcache_sb(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 859 | { |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 860 | LIST_HEAD(tmp); |
| 861 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 862 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 863 | while (!list_empty(&sb->s_dentry_lru)) { |
| 864 | list_splice_init(&sb->s_dentry_lru, &tmp); |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 865 | spin_unlock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 866 | shrink_dentry_list(&tmp); |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 867 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 868 | } |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 869 | spin_unlock(&dcache_lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 870 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 871 | EXPORT_SYMBOL(shrink_dcache_sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 872 | |
| 873 | /* |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 874 | * destroy a single subtree of dentries for unmount |
| 875 | * - see the comments on shrink_dcache_for_umount() for a description of the |
| 876 | * locking |
| 877 | */ |
| 878 | static void shrink_dcache_for_umount_subtree(struct dentry *dentry) |
| 879 | { |
| 880 | struct dentry *parent; |
| 881 | |
| 882 | BUG_ON(!IS_ROOT(dentry)); |
| 883 | |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 884 | for (;;) { |
| 885 | /* descend to the first leaf in the current subtree */ |
David Howells | 43c1c9c | 2011-06-07 14:09:30 +0100 | [diff] [blame] | 886 | while (!list_empty(&dentry->d_subdirs)) |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 887 | dentry = list_entry(dentry->d_subdirs.next, |
| 888 | struct dentry, d_u.d_child); |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 889 | |
| 890 | /* consume the dentries from this leaf up through its parents |
| 891 | * until we find one with children or run out altogether */ |
| 892 | do { |
| 893 | struct inode *inode; |
| 894 | |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 895 | /* |
Yan, Zheng | 61572bb | 2013-04-15 14:13:21 +0800 | [diff] [blame] | 896 | * inform the fs that this dentry is about to be |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 897 | * unhashed and destroyed. |
| 898 | */ |
Yan, Zheng | 61572bb | 2013-04-15 14:13:21 +0800 | [diff] [blame] | 899 | if (dentry->d_flags & DCACHE_OP_PRUNE) |
| 900 | dentry->d_op->d_prune(dentry); |
| 901 | |
| 902 | dentry_lru_del(dentry); |
David Howells | 43c1c9c | 2011-06-07 14:09:30 +0100 | [diff] [blame] | 903 | __d_shrink(dentry); |
| 904 | |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 905 | if (dentry->d_lockref.count != 0) { |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 906 | printk(KERN_ERR |
| 907 | "BUG: Dentry %p{i=%lx,n=%s}" |
| 908 | " still in use (%d)" |
| 909 | " [unmount of %s %s]\n", |
| 910 | dentry, |
| 911 | dentry->d_inode ? |
| 912 | dentry->d_inode->i_ino : 0UL, |
| 913 | dentry->d_name.name, |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 914 | dentry->d_lockref.count, |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 915 | dentry->d_sb->s_type->name, |
| 916 | dentry->d_sb->s_id); |
| 917 | BUG(); |
| 918 | } |
| 919 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 920 | if (IS_ROOT(dentry)) { |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 921 | parent = NULL; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 922 | list_del(&dentry->d_u.d_child); |
| 923 | } else { |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 924 | parent = dentry->d_parent; |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 925 | parent->d_lockref.count--; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 926 | list_del(&dentry->d_u.d_child); |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 927 | } |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 928 | |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 929 | inode = dentry->d_inode; |
| 930 | if (inode) { |
| 931 | dentry->d_inode = NULL; |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 932 | hlist_del_init(&dentry->d_alias); |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 933 | if (dentry->d_op && dentry->d_op->d_iput) |
| 934 | dentry->d_op->d_iput(dentry, inode); |
| 935 | else |
| 936 | iput(inode); |
| 937 | } |
| 938 | |
| 939 | d_free(dentry); |
| 940 | |
| 941 | /* finished when we fall off the top of the tree, |
| 942 | * otherwise we ascend to the parent and move to the |
| 943 | * next sibling if there is one */ |
| 944 | if (!parent) |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 945 | return; |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 946 | dentry = parent; |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 947 | } while (list_empty(&dentry->d_subdirs)); |
| 948 | |
| 949 | dentry = list_entry(dentry->d_subdirs.next, |
| 950 | struct dentry, d_u.d_child); |
| 951 | } |
| 952 | } |
| 953 | |
| 954 | /* |
| 955 | * destroy the dentries attached to a superblock on unmounting |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 956 | * - we don't need to use dentry->d_lock because: |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 957 | * - the superblock is detached from all mountings and open files, so the |
| 958 | * dentry trees will not be rearranged by the VFS |
| 959 | * - s_umount is write-locked, so the memory pressure shrinker will ignore |
| 960 | * any dentries belonging to this superblock that it comes across |
| 961 | * - the filesystem itself is no longer permitted to rearrange the dentries |
| 962 | * in this superblock |
| 963 | */ |
| 964 | void shrink_dcache_for_umount(struct super_block *sb) |
| 965 | { |
| 966 | struct dentry *dentry; |
| 967 | |
| 968 | if (down_read_trylock(&sb->s_umount)) |
| 969 | BUG(); |
| 970 | |
| 971 | dentry = sb->s_root; |
| 972 | sb->s_root = NULL; |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 973 | dentry->d_lockref.count--; |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 974 | shrink_dcache_for_umount_subtree(dentry); |
| 975 | |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 976 | while (!hlist_bl_empty(&sb->s_anon)) { |
| 977 | dentry = hlist_bl_entry(hlist_bl_first(&sb->s_anon), struct dentry, d_hash); |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 978 | shrink_dcache_for_umount_subtree(dentry); |
| 979 | } |
| 980 | } |
| 981 | |
| 982 | /* |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 983 | * This tries to ascend one level of parenthood, but |
| 984 | * we can race with renaming, so we need to re-check |
| 985 | * the parenthood after dropping the lock and check |
| 986 | * that the sequence number still matches. |
| 987 | */ |
| 988 | static struct dentry *try_to_ascend(struct dentry *old, int locked, unsigned seq) |
| 989 | { |
| 990 | struct dentry *new = old->d_parent; |
| 991 | |
| 992 | rcu_read_lock(); |
| 993 | spin_unlock(&old->d_lock); |
| 994 | spin_lock(&new->d_lock); |
| 995 | |
| 996 | /* |
| 997 | * might go back up the wrong parent if we have had a rename |
| 998 | * or deletion |
| 999 | */ |
| 1000 | if (new != old->d_parent || |
Miklos Szeredi | b161dfa6 | 2012-09-17 22:31:38 +0200 | [diff] [blame] | 1001 | (old->d_flags & DCACHE_DENTRY_KILLED) || |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 1002 | (!locked && read_seqretry(&rename_lock, seq))) { |
| 1003 | spin_unlock(&new->d_lock); |
| 1004 | new = NULL; |
| 1005 | } |
| 1006 | rcu_read_unlock(); |
| 1007 | return new; |
| 1008 | } |
| 1009 | |
| 1010 | |
| 1011 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1012 | * Search for at least 1 mount point in the dentry's subdirs. |
| 1013 | * We descend to the next level whenever the d_subdirs |
| 1014 | * list is non-empty and continue searching. |
| 1015 | */ |
| 1016 | |
| 1017 | /** |
| 1018 | * have_submounts - check for mounts over a dentry |
| 1019 | * @parent: dentry to check. |
| 1020 | * |
| 1021 | * Return true if the parent or its subdirectories contain |
| 1022 | * a mount point |
| 1023 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1024 | int have_submounts(struct dentry *parent) |
| 1025 | { |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1026 | struct dentry *this_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1027 | struct list_head *next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1028 | unsigned seq; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1029 | int locked = 0; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1030 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1031 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1032 | again: |
| 1033 | this_parent = parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1034 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1035 | if (d_mountpoint(parent)) |
| 1036 | goto positive; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1037 | spin_lock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1038 | repeat: |
| 1039 | next = this_parent->d_subdirs.next; |
| 1040 | resume: |
| 1041 | while (next != &this_parent->d_subdirs) { |
| 1042 | struct list_head *tmp = next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 1043 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1044 | next = tmp->next; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1045 | |
| 1046 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1047 | /* Have we found a mount point ? */ |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1048 | if (d_mountpoint(dentry)) { |
| 1049 | spin_unlock(&dentry->d_lock); |
| 1050 | spin_unlock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1051 | goto positive; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1052 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1053 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1054 | spin_unlock(&this_parent->d_lock); |
| 1055 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1056 | this_parent = dentry; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1057 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1058 | goto repeat; |
| 1059 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1060 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1061 | } |
| 1062 | /* |
| 1063 | * All done at this level ... ascend and resume the search. |
| 1064 | */ |
| 1065 | if (this_parent != parent) { |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 1066 | struct dentry *child = this_parent; |
| 1067 | this_parent = try_to_ascend(this_parent, locked, seq); |
| 1068 | if (!this_parent) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1069 | goto rename_retry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1070 | next = child->d_u.d_child.next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1071 | goto resume; |
| 1072 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1073 | spin_unlock(&this_parent->d_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1074 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1075 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1076 | if (locked) |
| 1077 | write_sequnlock(&rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1078 | return 0; /* No mount points found in tree */ |
| 1079 | positive: |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1080 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1081 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1082 | if (locked) |
| 1083 | write_sequnlock(&rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1084 | return 1; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1085 | |
| 1086 | rename_retry: |
Miklos Szeredi | 8110e16 | 2012-09-17 22:23:30 +0200 | [diff] [blame] | 1087 | if (locked) |
| 1088 | goto again; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1089 | locked = 1; |
| 1090 | write_seqlock(&rename_lock); |
| 1091 | goto again; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1092 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1093 | EXPORT_SYMBOL(have_submounts); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1094 | |
| 1095 | /* |
J. Bruce Fields | fd51790 | 2012-09-18 16:35:51 -0400 | [diff] [blame] | 1096 | * Search the dentry child list of the specified parent, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | * and move any unused dentries to the end of the unused |
| 1098 | * list for prune_dcache(). We descend to the next level |
| 1099 | * whenever the d_subdirs list is non-empty and continue |
| 1100 | * searching. |
| 1101 | * |
| 1102 | * It returns zero iff there are no unused children, |
| 1103 | * otherwise it returns the number of children moved to |
| 1104 | * the end of the unused list. This may not be the total |
| 1105 | * number of unused children, because select_parent can |
| 1106 | * drop the lock and return early due to latency |
| 1107 | * constraints. |
| 1108 | */ |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 1109 | static int select_parent(struct dentry *parent, struct list_head *dispose) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1110 | { |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1111 | struct dentry *this_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1112 | struct list_head *next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1113 | unsigned seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1114 | int found = 0; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1115 | int locked = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1116 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1117 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1118 | again: |
| 1119 | this_parent = parent; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1120 | spin_lock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1121 | repeat: |
| 1122 | next = this_parent->d_subdirs.next; |
| 1123 | resume: |
| 1124 | while (next != &this_parent->d_subdirs) { |
| 1125 | struct list_head *tmp = next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 1126 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1127 | next = tmp->next; |
| 1128 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1129 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 1130 | |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 1131 | /* |
| 1132 | * move only zero ref count dentries to the dispose list. |
Miklos Szeredi | eaf5f90 | 2012-01-10 18:22:25 +0100 | [diff] [blame] | 1133 | * |
| 1134 | * Those which are presently on the shrink list, being processed |
| 1135 | * by shrink_dentry_list(), shouldn't be moved. Otherwise the |
| 1136 | * loop in shrink_dcache_parent() might not make any progress |
| 1137 | * and loop forever. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1138 | */ |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 1139 | if (dentry->d_lockref.count) { |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 1140 | dentry_lru_del(dentry); |
Miklos Szeredi | eaf5f90 | 2012-01-10 18:22:25 +0100 | [diff] [blame] | 1141 | } else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) { |
| 1142 | dentry_lru_move_list(dentry, dispose); |
| 1143 | dentry->d_flags |= DCACHE_SHRINK_LIST; |
| 1144 | found++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1145 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1146 | /* |
| 1147 | * We can return to the caller if we have found some (this |
| 1148 | * ensures forward progress). We'll be coming back to find |
| 1149 | * the rest. |
| 1150 | */ |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1151 | if (found && need_resched()) { |
| 1152 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1153 | goto out; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1154 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1155 | |
| 1156 | /* |
| 1157 | * Descend a level if the d_subdirs list is non-empty. |
| 1158 | */ |
| 1159 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1160 | spin_unlock(&this_parent->d_lock); |
| 1161 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1162 | this_parent = dentry; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1163 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1164 | goto repeat; |
| 1165 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1166 | |
| 1167 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1168 | } |
| 1169 | /* |
| 1170 | * All done at this level ... ascend and resume the search. |
| 1171 | */ |
| 1172 | if (this_parent != parent) { |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 1173 | struct dentry *child = this_parent; |
| 1174 | this_parent = try_to_ascend(this_parent, locked, seq); |
| 1175 | if (!this_parent) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1176 | goto rename_retry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1177 | next = child->d_u.d_child.next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1178 | goto resume; |
| 1179 | } |
| 1180 | out: |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1181 | spin_unlock(&this_parent->d_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1182 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1183 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1184 | if (locked) |
| 1185 | write_sequnlock(&rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1186 | return found; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1187 | |
| 1188 | rename_retry: |
| 1189 | if (found) |
| 1190 | return found; |
Miklos Szeredi | 8110e16 | 2012-09-17 22:23:30 +0200 | [diff] [blame] | 1191 | if (locked) |
| 1192 | goto again; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1193 | locked = 1; |
| 1194 | write_seqlock(&rename_lock); |
| 1195 | goto again; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1196 | } |
| 1197 | |
| 1198 | /** |
| 1199 | * shrink_dcache_parent - prune dcache |
| 1200 | * @parent: parent of entries to prune |
| 1201 | * |
| 1202 | * Prune the dcache to remove unused children of the parent dentry. |
| 1203 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1204 | void shrink_dcache_parent(struct dentry * parent) |
| 1205 | { |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 1206 | LIST_HEAD(dispose); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1207 | int found; |
| 1208 | |
Greg Thelen | 421348f | 2013-04-30 15:26:48 -0700 | [diff] [blame] | 1209 | while ((found = select_parent(parent, &dispose)) != 0) { |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 1210 | shrink_dentry_list(&dispose); |
Greg Thelen | 421348f | 2013-04-30 15:26:48 -0700 | [diff] [blame] | 1211 | cond_resched(); |
| 1212 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1213 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1214 | EXPORT_SYMBOL(shrink_dcache_parent); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1215 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1216 | /** |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1217 | * __d_alloc - allocate a dcache entry |
| 1218 | * @sb: filesystem it will belong to |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1219 | * @name: qstr of the name |
| 1220 | * |
| 1221 | * Allocates a dentry. It returns %NULL if there is insufficient memory |
| 1222 | * available. On a success the dentry is returned. The name passed in is |
| 1223 | * copied and the copy passed in may be reused after this call. |
| 1224 | */ |
| 1225 | |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1226 | struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1227 | { |
| 1228 | struct dentry *dentry; |
| 1229 | char *dname; |
| 1230 | |
Mel Gorman | e12ba74 | 2007-10-16 01:25:52 -0700 | [diff] [blame] | 1231 | dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1232 | if (!dentry) |
| 1233 | return NULL; |
| 1234 | |
Linus Torvalds | 6326c71 | 2012-05-21 16:14:04 -0700 | [diff] [blame] | 1235 | /* |
| 1236 | * We guarantee that the inline name is always NUL-terminated. |
| 1237 | * This way the memcpy() done by the name switching in rename |
| 1238 | * will still always have a NUL at the end, even if we might |
| 1239 | * be overwriting an internal NUL character |
| 1240 | */ |
| 1241 | dentry->d_iname[DNAME_INLINE_LEN-1] = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1242 | if (name->len > DNAME_INLINE_LEN-1) { |
| 1243 | dname = kmalloc(name->len + 1, GFP_KERNEL); |
| 1244 | if (!dname) { |
| 1245 | kmem_cache_free(dentry_cache, dentry); |
| 1246 | return NULL; |
| 1247 | } |
| 1248 | } else { |
| 1249 | dname = dentry->d_iname; |
| 1250 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1251 | |
| 1252 | dentry->d_name.len = name->len; |
| 1253 | dentry->d_name.hash = name->hash; |
| 1254 | memcpy(dname, name->name, name->len); |
| 1255 | dname[name->len] = 0; |
| 1256 | |
Linus Torvalds | 6326c71 | 2012-05-21 16:14:04 -0700 | [diff] [blame] | 1257 | /* Make sure we always see the terminating NUL character */ |
| 1258 | smp_wmb(); |
| 1259 | dentry->d_name.name = dname; |
| 1260 | |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 1261 | dentry->d_lockref.count = 1; |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 1262 | dentry->d_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1263 | spin_lock_init(&dentry->d_lock); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1264 | seqcount_init(&dentry->d_seq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1265 | dentry->d_inode = NULL; |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1266 | dentry->d_parent = dentry; |
| 1267 | dentry->d_sb = sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1268 | dentry->d_op = NULL; |
| 1269 | dentry->d_fsdata = NULL; |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1270 | INIT_HLIST_BL_NODE(&dentry->d_hash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1271 | INIT_LIST_HEAD(&dentry->d_lru); |
| 1272 | INIT_LIST_HEAD(&dentry->d_subdirs); |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1273 | INIT_HLIST_NODE(&dentry->d_alias); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1274 | INIT_LIST_HEAD(&dentry->d_u.d_child); |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1275 | d_set_d_op(dentry, dentry->d_sb->s_d_op); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1276 | |
Nick Piggin | 3e880fb | 2011-01-07 17:49:19 +1100 | [diff] [blame] | 1277 | this_cpu_inc(nr_dentry); |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 1278 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1279 | return dentry; |
| 1280 | } |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1281 | |
| 1282 | /** |
| 1283 | * d_alloc - allocate a dcache entry |
| 1284 | * @parent: parent of entry to allocate |
| 1285 | * @name: qstr of the name |
| 1286 | * |
| 1287 | * Allocates a dentry. It returns %NULL if there is insufficient memory |
| 1288 | * available. On a success the dentry is returned. The name passed in is |
| 1289 | * copied and the copy passed in may be reused after this call. |
| 1290 | */ |
| 1291 | struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) |
| 1292 | { |
| 1293 | struct dentry *dentry = __d_alloc(parent->d_sb, name); |
| 1294 | if (!dentry) |
| 1295 | return NULL; |
| 1296 | |
| 1297 | spin_lock(&parent->d_lock); |
| 1298 | /* |
| 1299 | * don't need child lock because it is not subject |
| 1300 | * to concurrency here |
| 1301 | */ |
| 1302 | __dget_dlock(parent); |
| 1303 | dentry->d_parent = parent; |
| 1304 | list_add(&dentry->d_u.d_child, &parent->d_subdirs); |
| 1305 | spin_unlock(&parent->d_lock); |
| 1306 | |
| 1307 | return dentry; |
| 1308 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1309 | EXPORT_SYMBOL(d_alloc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1310 | |
Nick Piggin | 4b93688 | 2011-01-07 17:50:07 +1100 | [diff] [blame] | 1311 | struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name) |
| 1312 | { |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1313 | struct dentry *dentry = __d_alloc(sb, name); |
| 1314 | if (dentry) |
Nick Piggin | 4b93688 | 2011-01-07 17:50:07 +1100 | [diff] [blame] | 1315 | dentry->d_flags |= DCACHE_DISCONNECTED; |
Nick Piggin | 4b93688 | 2011-01-07 17:50:07 +1100 | [diff] [blame] | 1316 | return dentry; |
| 1317 | } |
| 1318 | EXPORT_SYMBOL(d_alloc_pseudo); |
| 1319 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1320 | struct dentry *d_alloc_name(struct dentry *parent, const char *name) |
| 1321 | { |
| 1322 | struct qstr q; |
| 1323 | |
| 1324 | q.name = name; |
| 1325 | q.len = strlen(name); |
| 1326 | q.hash = full_name_hash(q.name, q.len); |
| 1327 | return d_alloc(parent, &q); |
| 1328 | } |
H Hartley Sweeten | ef26ca9 | 2009-09-29 20:09:42 -0400 | [diff] [blame] | 1329 | EXPORT_SYMBOL(d_alloc_name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1330 | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1331 | void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) |
| 1332 | { |
Linus Torvalds | 6f7f7ca | 2011-01-14 13:26:18 -0800 | [diff] [blame] | 1333 | WARN_ON_ONCE(dentry->d_op); |
| 1334 | WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1335 | DCACHE_OP_COMPARE | |
| 1336 | DCACHE_OP_REVALIDATE | |
Jeff Layton | ecf3d1f | 2013-02-20 11:19:05 -0500 | [diff] [blame] | 1337 | DCACHE_OP_WEAK_REVALIDATE | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1338 | DCACHE_OP_DELETE )); |
| 1339 | dentry->d_op = op; |
| 1340 | if (!op) |
| 1341 | return; |
| 1342 | if (op->d_hash) |
| 1343 | dentry->d_flags |= DCACHE_OP_HASH; |
| 1344 | if (op->d_compare) |
| 1345 | dentry->d_flags |= DCACHE_OP_COMPARE; |
| 1346 | if (op->d_revalidate) |
| 1347 | dentry->d_flags |= DCACHE_OP_REVALIDATE; |
Jeff Layton | ecf3d1f | 2013-02-20 11:19:05 -0500 | [diff] [blame] | 1348 | if (op->d_weak_revalidate) |
| 1349 | dentry->d_flags |= DCACHE_OP_WEAK_REVALIDATE; |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1350 | if (op->d_delete) |
| 1351 | dentry->d_flags |= DCACHE_OP_DELETE; |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 1352 | if (op->d_prune) |
| 1353 | dentry->d_flags |= DCACHE_OP_PRUNE; |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1354 | |
| 1355 | } |
| 1356 | EXPORT_SYMBOL(d_set_d_op); |
| 1357 | |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1358 | static void __d_instantiate(struct dentry *dentry, struct inode *inode) |
| 1359 | { |
Nick Piggin | b23fb0a | 2011-01-07 17:49:35 +1100 | [diff] [blame] | 1360 | spin_lock(&dentry->d_lock); |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1361 | if (inode) { |
| 1362 | if (unlikely(IS_AUTOMOUNT(inode))) |
| 1363 | dentry->d_flags |= DCACHE_NEED_AUTOMOUNT; |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1364 | hlist_add_head(&dentry->d_alias, &inode->i_dentry); |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1365 | } |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1366 | dentry->d_inode = inode; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1367 | dentry_rcuwalk_barrier(dentry); |
Nick Piggin | b23fb0a | 2011-01-07 17:49:35 +1100 | [diff] [blame] | 1368 | spin_unlock(&dentry->d_lock); |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1369 | fsnotify_d_instantiate(dentry, inode); |
| 1370 | } |
| 1371 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1372 | /** |
| 1373 | * d_instantiate - fill in inode information for a dentry |
| 1374 | * @entry: dentry to complete |
| 1375 | * @inode: inode to attach to this dentry |
| 1376 | * |
| 1377 | * Fill in inode information in the entry. |
| 1378 | * |
| 1379 | * This turns negative dentries into productive full members |
| 1380 | * of society. |
| 1381 | * |
| 1382 | * NOTE! This assumes that the inode count has been incremented |
| 1383 | * (or otherwise set) by the caller to indicate that it is now |
| 1384 | * in use by the dcache. |
| 1385 | */ |
| 1386 | |
| 1387 | void d_instantiate(struct dentry *entry, struct inode * inode) |
| 1388 | { |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1389 | BUG_ON(!hlist_unhashed(&entry->d_alias)); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1390 | if (inode) |
| 1391 | spin_lock(&inode->i_lock); |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1392 | __d_instantiate(entry, inode); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1393 | if (inode) |
| 1394 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1395 | security_d_instantiate(entry, inode); |
| 1396 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1397 | EXPORT_SYMBOL(d_instantiate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1398 | |
| 1399 | /** |
| 1400 | * d_instantiate_unique - instantiate a non-aliased dentry |
| 1401 | * @entry: dentry to instantiate |
| 1402 | * @inode: inode to attach to this dentry |
| 1403 | * |
| 1404 | * Fill in inode information in the entry. On success, it returns NULL. |
| 1405 | * If an unhashed alias of "entry" already exists, then we return the |
Oleg Drokin | e866cfa | 2006-01-09 20:52:51 -0800 | [diff] [blame] | 1406 | * aliased dentry instead and drop one reference to inode. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1407 | * |
| 1408 | * Note that in order to avoid conflicts with rename() etc, the caller |
| 1409 | * had better be holding the parent directory semaphore. |
Oleg Drokin | e866cfa | 2006-01-09 20:52:51 -0800 | [diff] [blame] | 1410 | * |
| 1411 | * This also assumes that the inode count has been incremented |
| 1412 | * (or otherwise set) by the caller to indicate that it is now |
| 1413 | * in use by the dcache. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1414 | */ |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1415 | static struct dentry *__d_instantiate_unique(struct dentry *entry, |
| 1416 | struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1417 | { |
| 1418 | struct dentry *alias; |
| 1419 | int len = entry->d_name.len; |
| 1420 | const char *name = entry->d_name.name; |
| 1421 | unsigned int hash = entry->d_name.hash; |
| 1422 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1423 | if (!inode) { |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1424 | __d_instantiate(entry, NULL); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1425 | return NULL; |
| 1426 | } |
| 1427 | |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 1428 | hlist_for_each_entry(alias, &inode->i_dentry, d_alias) { |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 1429 | /* |
| 1430 | * Don't need alias->d_lock here, because aliases with |
| 1431 | * d_parent == entry->d_parent are not subject to name or |
| 1432 | * parent changes, because the parent inode i_mutex is held. |
| 1433 | */ |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1434 | if (alias->d_name.hash != hash) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1435 | continue; |
| 1436 | if (alias->d_parent != entry->d_parent) |
| 1437 | continue; |
Linus Torvalds | ee983e8 | 2012-05-10 12:37:10 -0700 | [diff] [blame] | 1438 | if (alias->d_name.len != len) |
| 1439 | continue; |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1440 | if (dentry_cmp(alias, name, len)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1441 | continue; |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 1442 | __dget(alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1443 | return alias; |
| 1444 | } |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1445 | |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1446 | __d_instantiate(entry, inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1447 | return NULL; |
| 1448 | } |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1449 | |
| 1450 | struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) |
| 1451 | { |
| 1452 | struct dentry *result; |
| 1453 | |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1454 | BUG_ON(!hlist_unhashed(&entry->d_alias)); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1455 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1456 | if (inode) |
| 1457 | spin_lock(&inode->i_lock); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1458 | result = __d_instantiate_unique(entry, inode); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1459 | if (inode) |
| 1460 | spin_unlock(&inode->i_lock); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1461 | |
| 1462 | if (!result) { |
| 1463 | security_d_instantiate(entry, inode); |
| 1464 | return NULL; |
| 1465 | } |
| 1466 | |
| 1467 | BUG_ON(!d_unhashed(result)); |
| 1468 | iput(inode); |
| 1469 | return result; |
| 1470 | } |
| 1471 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1472 | EXPORT_SYMBOL(d_instantiate_unique); |
| 1473 | |
Al Viro | adc0e91 | 2012-01-08 16:49:21 -0500 | [diff] [blame] | 1474 | struct dentry *d_make_root(struct inode *root_inode) |
| 1475 | { |
| 1476 | struct dentry *res = NULL; |
| 1477 | |
| 1478 | if (root_inode) { |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1479 | static const struct qstr name = QSTR_INIT("/", 1); |
Al Viro | adc0e91 | 2012-01-08 16:49:21 -0500 | [diff] [blame] | 1480 | |
| 1481 | res = __d_alloc(root_inode->i_sb, &name); |
| 1482 | if (res) |
| 1483 | d_instantiate(res, root_inode); |
| 1484 | else |
| 1485 | iput(root_inode); |
| 1486 | } |
| 1487 | return res; |
| 1488 | } |
| 1489 | EXPORT_SYMBOL(d_make_root); |
| 1490 | |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1491 | static struct dentry * __d_find_any_alias(struct inode *inode) |
| 1492 | { |
| 1493 | struct dentry *alias; |
| 1494 | |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1495 | if (hlist_empty(&inode->i_dentry)) |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1496 | return NULL; |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1497 | alias = hlist_entry(inode->i_dentry.first, struct dentry, d_alias); |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1498 | __dget(alias); |
| 1499 | return alias; |
| 1500 | } |
| 1501 | |
Sage Weil | 46f72b3 | 2012-01-10 09:04:37 -0800 | [diff] [blame] | 1502 | /** |
| 1503 | * d_find_any_alias - find any alias for a given inode |
| 1504 | * @inode: inode to find an alias for |
| 1505 | * |
| 1506 | * If any aliases exist for the given inode, take and return a |
| 1507 | * reference for one of them. If no aliases exist, return %NULL. |
| 1508 | */ |
| 1509 | struct dentry *d_find_any_alias(struct inode *inode) |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1510 | { |
| 1511 | struct dentry *de; |
| 1512 | |
| 1513 | spin_lock(&inode->i_lock); |
| 1514 | de = __d_find_any_alias(inode); |
| 1515 | spin_unlock(&inode->i_lock); |
| 1516 | return de; |
| 1517 | } |
Sage Weil | 46f72b3 | 2012-01-10 09:04:37 -0800 | [diff] [blame] | 1518 | EXPORT_SYMBOL(d_find_any_alias); |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1519 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1520 | /** |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1521 | * d_obtain_alias - find or allocate a dentry for a given inode |
| 1522 | * @inode: inode to allocate the dentry for |
| 1523 | * |
| 1524 | * Obtain a dentry for an inode resulting from NFS filehandle conversion or |
| 1525 | * similar open by handle operations. The returned dentry may be anonymous, |
| 1526 | * or may have a full name (if the inode was already in the cache). |
| 1527 | * |
| 1528 | * When called on a directory inode, we must ensure that the inode only ever |
| 1529 | * has one dentry. If a dentry is found, that is returned instead of |
| 1530 | * allocating a new one. |
| 1531 | * |
| 1532 | * On successful return, the reference to the inode has been transferred |
Christoph Hellwig | 4400372 | 2008-08-11 15:49:04 +0200 | [diff] [blame] | 1533 | * to the dentry. In case of an error the reference on the inode is released. |
| 1534 | * To make it easier to use in export operations a %NULL or IS_ERR inode may |
| 1535 | * be passed in and will be the error will be propagate to the return value, |
| 1536 | * with a %NULL @inode replaced by ERR_PTR(-ESTALE). |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1537 | */ |
| 1538 | struct dentry *d_obtain_alias(struct inode *inode) |
| 1539 | { |
NeilBrown | b911a6b | 2012-11-08 16:09:37 -0800 | [diff] [blame] | 1540 | static const struct qstr anonstring = QSTR_INIT("/", 1); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1541 | struct dentry *tmp; |
| 1542 | struct dentry *res; |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1543 | |
| 1544 | if (!inode) |
Christoph Hellwig | 4400372 | 2008-08-11 15:49:04 +0200 | [diff] [blame] | 1545 | return ERR_PTR(-ESTALE); |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1546 | if (IS_ERR(inode)) |
| 1547 | return ERR_CAST(inode); |
| 1548 | |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1549 | res = d_find_any_alias(inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1550 | if (res) |
| 1551 | goto out_iput; |
| 1552 | |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1553 | tmp = __d_alloc(inode->i_sb, &anonstring); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1554 | if (!tmp) { |
| 1555 | res = ERR_PTR(-ENOMEM); |
| 1556 | goto out_iput; |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1557 | } |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 1558 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1559 | spin_lock(&inode->i_lock); |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1560 | res = __d_find_any_alias(inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1561 | if (res) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1562 | spin_unlock(&inode->i_lock); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1563 | dput(tmp); |
| 1564 | goto out_iput; |
| 1565 | } |
| 1566 | |
| 1567 | /* attach a disconnected dentry */ |
| 1568 | spin_lock(&tmp->d_lock); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1569 | tmp->d_inode = inode; |
| 1570 | tmp->d_flags |= DCACHE_DISCONNECTED; |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1571 | hlist_add_head(&tmp->d_alias, &inode->i_dentry); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 1572 | hlist_bl_lock(&tmp->d_sb->s_anon); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1573 | hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 1574 | hlist_bl_unlock(&tmp->d_sb->s_anon); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1575 | spin_unlock(&tmp->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1576 | spin_unlock(&inode->i_lock); |
Josef Bacik | 24ff666 | 2010-11-18 20:52:55 -0500 | [diff] [blame] | 1577 | security_d_instantiate(tmp, inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1578 | |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1579 | return tmp; |
| 1580 | |
| 1581 | out_iput: |
Josef Bacik | 24ff666 | 2010-11-18 20:52:55 -0500 | [diff] [blame] | 1582 | if (res && !IS_ERR(res)) |
| 1583 | security_d_instantiate(res, inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1584 | iput(inode); |
| 1585 | return res; |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1586 | } |
Benny Halevy | adc4872 | 2009-02-27 14:02:59 -0800 | [diff] [blame] | 1587 | EXPORT_SYMBOL(d_obtain_alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1588 | |
| 1589 | /** |
| 1590 | * d_splice_alias - splice a disconnected dentry into the tree if one exists |
| 1591 | * @inode: the inode which may have a disconnected dentry |
| 1592 | * @dentry: a negative dentry which we want to point to the inode. |
| 1593 | * |
| 1594 | * If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and |
| 1595 | * DCACHE_DISCONNECTED), then d_move that in place of the given dentry |
| 1596 | * and return it, else simply d_add the inode to the dentry and return NULL. |
| 1597 | * |
| 1598 | * This is needed in the lookup routine of any filesystem that is exportable |
| 1599 | * (via knfsd) so that we can build dcache paths to directories effectively. |
| 1600 | * |
| 1601 | * If a dentry was found and moved, then it is returned. Otherwise NULL |
| 1602 | * is returned. This matches the expected return value of ->lookup. |
| 1603 | * |
Steven Whitehouse | 6d4ade9 | 2013-06-14 11:17:15 +0100 | [diff] [blame] | 1604 | * Cluster filesystems may call this function with a negative, hashed dentry. |
| 1605 | * In that case, we know that the inode will be a regular file, and also this |
| 1606 | * will only occur during atomic_open. So we need to check for the dentry |
| 1607 | * being already hashed only in the final case. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1608 | */ |
| 1609 | struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) |
| 1610 | { |
| 1611 | struct dentry *new = NULL; |
| 1612 | |
Al Viro | a904937 | 2011-07-08 21:20:11 -0400 | [diff] [blame] | 1613 | if (IS_ERR(inode)) |
| 1614 | return ERR_CAST(inode); |
| 1615 | |
NeilBrown | 21c0d8f | 2006-10-04 02:16:16 -0700 | [diff] [blame] | 1616 | if (inode && S_ISDIR(inode->i_mode)) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1617 | spin_lock(&inode->i_lock); |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 1618 | new = __d_find_alias(inode, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1619 | if (new) { |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 1620 | BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED)); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1621 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1622 | security_d_instantiate(new, inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1623 | d_move(new, dentry); |
| 1624 | iput(inode); |
| 1625 | } else { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1626 | /* already taking inode->i_lock, so d_add() by hand */ |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1627 | __d_instantiate(dentry, inode); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1628 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1629 | security_d_instantiate(dentry, inode); |
| 1630 | d_rehash(dentry); |
| 1631 | } |
Steven Whitehouse | 6d4ade9 | 2013-06-14 11:17:15 +0100 | [diff] [blame] | 1632 | } else { |
| 1633 | d_instantiate(dentry, inode); |
| 1634 | if (d_unhashed(dentry)) |
| 1635 | d_rehash(dentry); |
| 1636 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1637 | return new; |
| 1638 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1639 | EXPORT_SYMBOL(d_splice_alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1640 | |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1641 | /** |
| 1642 | * d_add_ci - lookup or allocate new dentry with case-exact name |
| 1643 | * @inode: the inode case-insensitive lookup has found |
| 1644 | * @dentry: the negative dentry that was passed to the parent's lookup func |
| 1645 | * @name: the case-exact name to be associated with the returned dentry |
| 1646 | * |
| 1647 | * This is to avoid filling the dcache with case-insensitive names to the |
| 1648 | * same inode, only the actual correct case is stored in the dcache for |
| 1649 | * case-insensitive filesystems. |
| 1650 | * |
| 1651 | * For a case-insensitive lookup match and if the the case-exact dentry |
| 1652 | * already exists in in the dcache, use it and return it. |
| 1653 | * |
| 1654 | * If no entry exists with the exact case name, allocate new dentry with |
| 1655 | * the exact case, and return the spliced entry. |
| 1656 | */ |
Christoph Hellwig | e45b590 | 2008-08-07 23:49:07 +0200 | [diff] [blame] | 1657 | struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1658 | struct qstr *name) |
| 1659 | { |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1660 | struct dentry *found; |
| 1661 | struct dentry *new; |
| 1662 | |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1663 | /* |
| 1664 | * First check if a dentry matching the name already exists, |
| 1665 | * if not go ahead and create it now. |
| 1666 | */ |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1667 | found = d_hash_and_lookup(dentry->d_parent, name); |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1668 | if (unlikely(IS_ERR(found))) |
| 1669 | goto err_out; |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1670 | if (!found) { |
| 1671 | new = d_alloc(dentry->d_parent, name); |
| 1672 | if (!new) { |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1673 | found = ERR_PTR(-ENOMEM); |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1674 | goto err_out; |
| 1675 | } |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1676 | |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1677 | found = d_splice_alias(inode, new); |
| 1678 | if (found) { |
| 1679 | dput(new); |
| 1680 | return found; |
| 1681 | } |
| 1682 | return new; |
| 1683 | } |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1684 | |
| 1685 | /* |
| 1686 | * If a matching dentry exists, and it's not negative use it. |
| 1687 | * |
| 1688 | * Decrement the reference count to balance the iget() done |
| 1689 | * earlier on. |
| 1690 | */ |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1691 | if (found->d_inode) { |
| 1692 | if (unlikely(found->d_inode != inode)) { |
| 1693 | /* This can't happen because bad inodes are unhashed. */ |
| 1694 | BUG_ON(!is_bad_inode(inode)); |
| 1695 | BUG_ON(!is_bad_inode(found->d_inode)); |
| 1696 | } |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1697 | iput(inode); |
| 1698 | return found; |
| 1699 | } |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1700 | |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1701 | /* |
| 1702 | * Negative dentry: instantiate it unless the inode is a directory and |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1703 | * already has a dentry. |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1704 | */ |
Al Viro | 4513d89 | 2011-07-17 10:52:14 -0400 | [diff] [blame] | 1705 | new = d_splice_alias(inode, found); |
| 1706 | if (new) { |
| 1707 | dput(found); |
| 1708 | found = new; |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1709 | } |
Al Viro | 4513d89 | 2011-07-17 10:52:14 -0400 | [diff] [blame] | 1710 | return found; |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1711 | |
| 1712 | err_out: |
| 1713 | iput(inode); |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1714 | return found; |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1715 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1716 | EXPORT_SYMBOL(d_add_ci); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1717 | |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1718 | /* |
| 1719 | * Do the slow-case of the dentry name compare. |
| 1720 | * |
| 1721 | * Unlike the dentry_cmp() function, we need to atomically |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1722 | * load the name and length information, so that the |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1723 | * filesystem can rely on them, and can use the 'name' and |
| 1724 | * 'len' information without worrying about walking off the |
| 1725 | * end of memory etc. |
| 1726 | * |
| 1727 | * Thus the read_seqcount_retry() and the "duplicate" info |
| 1728 | * in arguments (the low-level filesystem should not look |
| 1729 | * at the dentry inode or name contents directly, since |
| 1730 | * rename can change them while we're in RCU mode). |
| 1731 | */ |
| 1732 | enum slow_d_compare { |
| 1733 | D_COMP_OK, |
| 1734 | D_COMP_NOMATCH, |
| 1735 | D_COMP_SEQRETRY, |
| 1736 | }; |
| 1737 | |
| 1738 | static noinline enum slow_d_compare slow_dentry_cmp( |
| 1739 | const struct dentry *parent, |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1740 | struct dentry *dentry, |
| 1741 | unsigned int seq, |
| 1742 | const struct qstr *name) |
| 1743 | { |
| 1744 | int tlen = dentry->d_name.len; |
| 1745 | const char *tname = dentry->d_name.name; |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1746 | |
| 1747 | if (read_seqcount_retry(&dentry->d_seq, seq)) { |
| 1748 | cpu_relax(); |
| 1749 | return D_COMP_SEQRETRY; |
| 1750 | } |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1751 | if (parent->d_op->d_compare(parent, dentry, tlen, tname, name)) |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1752 | return D_COMP_NOMATCH; |
| 1753 | return D_COMP_OK; |
| 1754 | } |
| 1755 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1756 | /** |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1757 | * __d_lookup_rcu - search for a dentry (racy, store-free) |
| 1758 | * @parent: parent dentry |
| 1759 | * @name: qstr of name we wish to find |
Randy Dunlap | 1f1e6e5 | 2012-03-18 21:23:05 -0700 | [diff] [blame] | 1760 | * @seqp: returns d_seq value at the point where the dentry was found |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1761 | * Returns: dentry, or NULL |
| 1762 | * |
| 1763 | * __d_lookup_rcu is the dcache lookup function for rcu-walk name |
| 1764 | * resolution (store-free path walking) design described in |
| 1765 | * Documentation/filesystems/path-lookup.txt. |
| 1766 | * |
| 1767 | * This is not to be used outside core vfs. |
| 1768 | * |
| 1769 | * __d_lookup_rcu must only be used in rcu-walk mode, ie. with vfsmount lock |
| 1770 | * held, and rcu_read_lock held. The returned dentry must not be stored into |
| 1771 | * without taking d_lock and checking d_seq sequence count against @seq |
| 1772 | * returned here. |
| 1773 | * |
| 1774 | * A refcount may be taken on the found dentry with the __d_rcu_to_refcount |
| 1775 | * function. |
| 1776 | * |
| 1777 | * Alternatively, __d_lookup_rcu may be called again to look up the child of |
| 1778 | * the returned dentry, so long as its parent's seqlock is checked after the |
| 1779 | * child is looked up. Thus, an interlocking stepping of sequence lock checks |
| 1780 | * is formed, giving integrity down the path walk. |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1781 | * |
| 1782 | * NOTE! The caller *has* to check the resulting dentry against the sequence |
| 1783 | * number we've returned before using any of the resulting dentry state! |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1784 | */ |
Linus Torvalds | 8966be9 | 2012-03-02 14:23:30 -0800 | [diff] [blame] | 1785 | struct dentry *__d_lookup_rcu(const struct dentry *parent, |
| 1786 | const struct qstr *name, |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1787 | unsigned *seqp) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1788 | { |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1789 | u64 hashlen = name->hash_len; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1790 | const unsigned char *str = name->name; |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1791 | struct hlist_bl_head *b = d_hash(parent, hashlen_hash(hashlen)); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1792 | struct hlist_bl_node *node; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1793 | struct dentry *dentry; |
| 1794 | |
| 1795 | /* |
| 1796 | * Note: There is significant duplication with __d_lookup_rcu which is |
| 1797 | * required to prevent single threaded performance regressions |
| 1798 | * especially on architectures where smp_rmb (in seqcounts) are costly. |
| 1799 | * Keep the two functions in sync. |
| 1800 | */ |
| 1801 | |
| 1802 | /* |
| 1803 | * The hash list is protected using RCU. |
| 1804 | * |
| 1805 | * Carefully use d_seq when comparing a candidate dentry, to avoid |
| 1806 | * races with d_move(). |
| 1807 | * |
| 1808 | * It is possible that concurrent renames can mess up our list |
| 1809 | * walk here and result in missing our dentry, resulting in the |
| 1810 | * false-negative result. d_lookup() protects against concurrent |
| 1811 | * renames using rename_lock seqlock. |
| 1812 | * |
Namhyung Kim | b0a4bb8 | 2011-01-22 15:31:32 +0900 | [diff] [blame] | 1813 | * See Documentation/filesystems/path-lookup.txt for more details. |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1814 | */ |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 1815 | hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { |
Linus Torvalds | 8966be9 | 2012-03-02 14:23:30 -0800 | [diff] [blame] | 1816 | unsigned seq; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1817 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1818 | seqretry: |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1819 | /* |
| 1820 | * The dentry sequence count protects us from concurrent |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1821 | * renames, and thus protects parent and name fields. |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1822 | * |
| 1823 | * The caller must perform a seqcount check in order |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1824 | * to do anything useful with the returned dentry. |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1825 | * |
| 1826 | * NOTE! We do a "raw" seqcount_begin here. That means that |
| 1827 | * we don't wait for the sequence count to stabilize if it |
| 1828 | * is in the middle of a sequence change. If we do the slow |
| 1829 | * dentry compare, we will do seqretries until it is stable, |
| 1830 | * and if we end up with a successful lookup, we actually |
| 1831 | * want to exit RCU lookup anyway. |
| 1832 | */ |
| 1833 | seq = raw_seqcount_begin(&dentry->d_seq); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1834 | if (dentry->d_parent != parent) |
| 1835 | continue; |
Linus Torvalds | 2e32180 | 2012-05-21 18:48:10 -0700 | [diff] [blame] | 1836 | if (d_unhashed(dentry)) |
| 1837 | continue; |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1838 | |
| 1839 | if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1840 | if (dentry->d_name.hash != hashlen_hash(hashlen)) |
| 1841 | continue; |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1842 | *seqp = seq; |
| 1843 | switch (slow_dentry_cmp(parent, dentry, seq, name)) { |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1844 | case D_COMP_OK: |
| 1845 | return dentry; |
| 1846 | case D_COMP_NOMATCH: |
| 1847 | continue; |
| 1848 | default: |
| 1849 | goto seqretry; |
| 1850 | } |
| 1851 | } |
| 1852 | |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1853 | if (dentry->d_name.hash_len != hashlen) |
Linus Torvalds | ee983e8 | 2012-05-10 12:37:10 -0700 | [diff] [blame] | 1854 | continue; |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1855 | *seqp = seq; |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1856 | if (!dentry_cmp(dentry, str, hashlen_len(hashlen))) |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1857 | return dentry; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1858 | } |
| 1859 | return NULL; |
| 1860 | } |
| 1861 | |
| 1862 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1863 | * d_lookup - search for a dentry |
| 1864 | * @parent: parent dentry |
| 1865 | * @name: qstr of name we wish to find |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1866 | * Returns: dentry, or NULL |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1867 | * |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1868 | * d_lookup searches the children of the parent dentry for the name in |
| 1869 | * question. If the dentry is found its reference count is incremented and the |
| 1870 | * dentry is returned. The caller must use dput to free the entry when it has |
| 1871 | * finished using it. %NULL is returned if the dentry does not exist. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1872 | */ |
Al Viro | da2d845 | 2013-01-24 18:29:34 -0500 | [diff] [blame] | 1873 | struct dentry *d_lookup(const struct dentry *parent, const struct qstr *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1874 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1875 | struct dentry *dentry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1876 | unsigned seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1877 | |
| 1878 | do { |
| 1879 | seq = read_seqbegin(&rename_lock); |
| 1880 | dentry = __d_lookup(parent, name); |
| 1881 | if (dentry) |
| 1882 | break; |
| 1883 | } while (read_seqretry(&rename_lock, seq)); |
| 1884 | return dentry; |
| 1885 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1886 | EXPORT_SYMBOL(d_lookup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1887 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1888 | /** |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1889 | * __d_lookup - search for a dentry (racy) |
| 1890 | * @parent: parent dentry |
| 1891 | * @name: qstr of name we wish to find |
| 1892 | * Returns: dentry, or NULL |
| 1893 | * |
| 1894 | * __d_lookup is like d_lookup, however it may (rarely) return a |
| 1895 | * false-negative result due to unrelated rename activity. |
| 1896 | * |
| 1897 | * __d_lookup is slightly faster by avoiding rename_lock read seqlock, |
| 1898 | * however it must be used carefully, eg. with a following d_lookup in |
| 1899 | * the case of failure. |
| 1900 | * |
| 1901 | * __d_lookup callers must be commented. |
| 1902 | */ |
Al Viro | a713ca2 | 2013-01-24 18:27:00 -0500 | [diff] [blame] | 1903 | struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1904 | { |
| 1905 | unsigned int len = name->len; |
| 1906 | unsigned int hash = name->hash; |
| 1907 | const unsigned char *str = name->name; |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 1908 | struct hlist_bl_head *b = d_hash(parent, hash); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1909 | struct hlist_bl_node *node; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1910 | struct dentry *found = NULL; |
Paul E. McKenney | 665a758 | 2005-11-07 00:59:17 -0800 | [diff] [blame] | 1911 | struct dentry *dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1912 | |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1913 | /* |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1914 | * Note: There is significant duplication with __d_lookup_rcu which is |
| 1915 | * required to prevent single threaded performance regressions |
| 1916 | * especially on architectures where smp_rmb (in seqcounts) are costly. |
| 1917 | * Keep the two functions in sync. |
| 1918 | */ |
| 1919 | |
| 1920 | /* |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1921 | * The hash list is protected using RCU. |
| 1922 | * |
| 1923 | * Take d_lock when comparing a candidate dentry, to avoid races |
| 1924 | * with d_move(). |
| 1925 | * |
| 1926 | * It is possible that concurrent renames can mess up our list |
| 1927 | * walk here and result in missing our dentry, resulting in the |
| 1928 | * false-negative result. d_lookup() protects against concurrent |
| 1929 | * renames using rename_lock seqlock. |
| 1930 | * |
Namhyung Kim | b0a4bb8 | 2011-01-22 15:31:32 +0900 | [diff] [blame] | 1931 | * See Documentation/filesystems/path-lookup.txt for more details. |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1932 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1933 | rcu_read_lock(); |
| 1934 | |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 1935 | hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1936 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1937 | if (dentry->d_name.hash != hash) |
| 1938 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1939 | |
| 1940 | spin_lock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1941 | if (dentry->d_parent != parent) |
| 1942 | goto next; |
Linus Torvalds | d0185c0 | 2008-09-29 07:42:57 -0700 | [diff] [blame] | 1943 | if (d_unhashed(dentry)) |
| 1944 | goto next; |
| 1945 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1946 | /* |
| 1947 | * It is safe to compare names since d_move() cannot |
| 1948 | * change the qstr (protected by d_lock). |
| 1949 | */ |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1950 | if (parent->d_flags & DCACHE_OP_COMPARE) { |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1951 | int tlen = dentry->d_name.len; |
| 1952 | const char *tname = dentry->d_name.name; |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1953 | if (parent->d_op->d_compare(parent, dentry, tlen, tname, name)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1954 | goto next; |
| 1955 | } else { |
Linus Torvalds | ee983e8 | 2012-05-10 12:37:10 -0700 | [diff] [blame] | 1956 | if (dentry->d_name.len != len) |
| 1957 | goto next; |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1958 | if (dentry_cmp(dentry, str, len)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1959 | goto next; |
| 1960 | } |
| 1961 | |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 1962 | dentry->d_lockref.count++; |
Linus Torvalds | d0185c0 | 2008-09-29 07:42:57 -0700 | [diff] [blame] | 1963 | found = dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1964 | spin_unlock(&dentry->d_lock); |
| 1965 | break; |
| 1966 | next: |
| 1967 | spin_unlock(&dentry->d_lock); |
| 1968 | } |
| 1969 | rcu_read_unlock(); |
| 1970 | |
| 1971 | return found; |
| 1972 | } |
| 1973 | |
| 1974 | /** |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 1975 | * d_hash_and_lookup - hash the qstr then search for a dentry |
| 1976 | * @dir: Directory to search in |
| 1977 | * @name: qstr of name we wish to find |
| 1978 | * |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1979 | * On lookup failure NULL is returned; on bad name - ERR_PTR(-error) |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 1980 | */ |
| 1981 | struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name) |
| 1982 | { |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 1983 | /* |
| 1984 | * Check for a fs-specific hash function. Note that we must |
| 1985 | * calculate the standard hash first, as the d_op->d_hash() |
| 1986 | * routine may choose to leave the hash value unchanged. |
| 1987 | */ |
| 1988 | name->hash = full_name_hash(name->name, name->len); |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1989 | if (dir->d_flags & DCACHE_OP_HASH) { |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1990 | int err = dir->d_op->d_hash(dir, name); |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1991 | if (unlikely(err < 0)) |
| 1992 | return ERR_PTR(err); |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 1993 | } |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1994 | return d_lookup(dir, name); |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 1995 | } |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1996 | EXPORT_SYMBOL(d_hash_and_lookup); |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 1997 | |
| 1998 | /** |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 1999 | * d_validate - verify dentry provided from insecure source (deprecated) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2000 | * @dentry: The dentry alleged to be valid child of @dparent |
Randy Dunlap | ff5fdb6 | 2011-01-22 20:16:06 -0800 | [diff] [blame] | 2001 | * @dparent: The parent dentry (known to be valid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2002 | * |
| 2003 | * An insecure source has sent us a dentry, here we verify it and dget() it. |
| 2004 | * This is used by ncpfs in its readdir implementation. |
| 2005 | * Zero is returned in the dentry is invalid. |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 2006 | * |
| 2007 | * This function is slow for big directories, and deprecated, do not use it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2008 | */ |
Nick Piggin | d3a23e1 | 2011-01-05 20:01:21 +1100 | [diff] [blame] | 2009 | int d_validate(struct dentry *dentry, struct dentry *dparent) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2010 | { |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 2011 | struct dentry *child; |
Nick Piggin | d3a23e1 | 2011-01-05 20:01:21 +1100 | [diff] [blame] | 2012 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2013 | spin_lock(&dparent->d_lock); |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 2014 | list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) { |
| 2015 | if (dentry == child) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2016 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 2017 | __dget_dlock(dentry); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2018 | spin_unlock(&dentry->d_lock); |
| 2019 | spin_unlock(&dparent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2020 | return 1; |
| 2021 | } |
| 2022 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2023 | spin_unlock(&dparent->d_lock); |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 2024 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2025 | return 0; |
| 2026 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2027 | EXPORT_SYMBOL(d_validate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2028 | |
| 2029 | /* |
| 2030 | * When a file is deleted, we have two options: |
| 2031 | * - turn this dentry into a negative dentry |
| 2032 | * - unhash this dentry and free it. |
| 2033 | * |
| 2034 | * Usually, we want to just turn this into |
| 2035 | * a negative dentry, but if anybody else is |
| 2036 | * currently using the dentry or the inode |
| 2037 | * we can't do that and we fall back on removing |
| 2038 | * it from the hash queues and waiting for |
| 2039 | * it to be deleted later when it has no users |
| 2040 | */ |
| 2041 | |
| 2042 | /** |
| 2043 | * d_delete - delete a dentry |
| 2044 | * @dentry: The dentry to delete |
| 2045 | * |
| 2046 | * Turn the dentry into a negative dentry if possible, otherwise |
| 2047 | * remove it from the hash queues so it can be deleted later |
| 2048 | */ |
| 2049 | |
| 2050 | void d_delete(struct dentry * dentry) |
| 2051 | { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2052 | struct inode *inode; |
John McCutchan | 7a91bf7 | 2005-08-08 13:52:16 -0400 | [diff] [blame] | 2053 | int isdir = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2054 | /* |
| 2055 | * Are we the only user? |
| 2056 | */ |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2057 | again: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2058 | spin_lock(&dentry->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2059 | inode = dentry->d_inode; |
| 2060 | isdir = S_ISDIR(inode->i_mode); |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 2061 | if (dentry->d_lockref.count == 1) { |
Alan Cox | 1fe0c02 | 2012-09-19 15:49:51 +0100 | [diff] [blame] | 2062 | if (!spin_trylock(&inode->i_lock)) { |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2063 | spin_unlock(&dentry->d_lock); |
| 2064 | cpu_relax(); |
| 2065 | goto again; |
| 2066 | } |
Al Viro | 13e3c5e | 2010-05-21 16:11:04 -0400 | [diff] [blame] | 2067 | dentry->d_flags &= ~DCACHE_CANT_MOUNT; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2068 | dentry_unlink_inode(dentry); |
John McCutchan | 7a91bf7 | 2005-08-08 13:52:16 -0400 | [diff] [blame] | 2069 | fsnotify_nameremove(dentry, isdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2070 | return; |
| 2071 | } |
| 2072 | |
| 2073 | if (!d_unhashed(dentry)) |
| 2074 | __d_drop(dentry); |
| 2075 | |
| 2076 | spin_unlock(&dentry->d_lock); |
John McCutchan | 7a91bf7 | 2005-08-08 13:52:16 -0400 | [diff] [blame] | 2077 | |
| 2078 | fsnotify_nameremove(dentry, isdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2079 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2080 | EXPORT_SYMBOL(d_delete); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2081 | |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 2082 | static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2083 | { |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 2084 | BUG_ON(!d_unhashed(entry)); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 2085 | hlist_bl_lock(b); |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 2086 | entry->d_flags |= DCACHE_RCUACCESS; |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 2087 | hlist_bl_add_head_rcu(&entry->d_hash, b); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 2088 | hlist_bl_unlock(b); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2089 | } |
| 2090 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2091 | static void _d_rehash(struct dentry * entry) |
| 2092 | { |
| 2093 | __d_rehash(entry, d_hash(entry->d_parent, entry->d_name.hash)); |
| 2094 | } |
| 2095 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2096 | /** |
| 2097 | * d_rehash - add an entry back to the hash |
| 2098 | * @entry: dentry to add to the hash |
| 2099 | * |
| 2100 | * Adds a dentry to the hash according to its name. |
| 2101 | */ |
| 2102 | |
| 2103 | void d_rehash(struct dentry * entry) |
| 2104 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2105 | spin_lock(&entry->d_lock); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2106 | _d_rehash(entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2107 | spin_unlock(&entry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2108 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2109 | EXPORT_SYMBOL(d_rehash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2110 | |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2111 | /** |
| 2112 | * dentry_update_name_case - update case insensitive dentry with a new name |
| 2113 | * @dentry: dentry to be updated |
| 2114 | * @name: new name |
| 2115 | * |
| 2116 | * Update a case insensitive dentry with new case of name. |
| 2117 | * |
| 2118 | * dentry must have been returned by d_lookup with name @name. Old and new |
| 2119 | * name lengths must match (ie. no d_compare which allows mismatched name |
| 2120 | * lengths). |
| 2121 | * |
| 2122 | * Parent inode i_mutex must be held over d_lookup and into this call (to |
| 2123 | * keep renames and concurrent inserts, and readdir(2) away). |
| 2124 | */ |
| 2125 | void dentry_update_name_case(struct dentry *dentry, struct qstr *name) |
| 2126 | { |
Linus Torvalds | 7ebfa57 | 2011-04-15 07:34:26 -0700 | [diff] [blame] | 2127 | BUG_ON(!mutex_is_locked(&dentry->d_parent->d_inode->i_mutex)); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2128 | BUG_ON(dentry->d_name.len != name->len); /* d_lookup gives this */ |
| 2129 | |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2130 | spin_lock(&dentry->d_lock); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2131 | write_seqcount_begin(&dentry->d_seq); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2132 | memcpy((unsigned char *)dentry->d_name.name, name->name, name->len); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2133 | write_seqcount_end(&dentry->d_seq); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2134 | spin_unlock(&dentry->d_lock); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2135 | } |
| 2136 | EXPORT_SYMBOL(dentry_update_name_case); |
| 2137 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2138 | static void switch_names(struct dentry *dentry, struct dentry *target) |
| 2139 | { |
| 2140 | if (dname_external(target)) { |
| 2141 | if (dname_external(dentry)) { |
| 2142 | /* |
| 2143 | * Both external: swap the pointers |
| 2144 | */ |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2145 | swap(target->d_name.name, dentry->d_name.name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2146 | } else { |
| 2147 | /* |
| 2148 | * dentry:internal, target:external. Steal target's |
| 2149 | * storage and make target internal. |
| 2150 | */ |
J. Bruce Fields | 321bcf9 | 2007-10-21 16:41:38 -0700 | [diff] [blame] | 2151 | memcpy(target->d_iname, dentry->d_name.name, |
| 2152 | dentry->d_name.len + 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2153 | dentry->d_name.name = target->d_name.name; |
| 2154 | target->d_name.name = target->d_iname; |
| 2155 | } |
| 2156 | } else { |
| 2157 | if (dname_external(dentry)) { |
| 2158 | /* |
| 2159 | * dentry:external, target:internal. Give dentry's |
| 2160 | * storage to target and make dentry internal |
| 2161 | */ |
| 2162 | memcpy(dentry->d_iname, target->d_name.name, |
| 2163 | target->d_name.len + 1); |
| 2164 | target->d_name.name = dentry->d_name.name; |
| 2165 | dentry->d_name.name = dentry->d_iname; |
| 2166 | } else { |
| 2167 | /* |
| 2168 | * Both are internal. Just copy target to dentry |
| 2169 | */ |
| 2170 | memcpy(dentry->d_iname, target->d_name.name, |
| 2171 | target->d_name.len + 1); |
Al Viro | dc711ca | 2008-11-03 15:03:50 -0500 | [diff] [blame] | 2172 | dentry->d_name.len = target->d_name.len; |
| 2173 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2174 | } |
| 2175 | } |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2176 | swap(dentry->d_name.len, target->d_name.len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2177 | } |
| 2178 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2179 | static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target) |
| 2180 | { |
| 2181 | /* |
| 2182 | * XXXX: do we really need to take target->d_lock? |
| 2183 | */ |
| 2184 | if (IS_ROOT(dentry) || dentry->d_parent == target->d_parent) |
| 2185 | spin_lock(&target->d_parent->d_lock); |
| 2186 | else { |
| 2187 | if (d_ancestor(dentry->d_parent, target->d_parent)) { |
| 2188 | spin_lock(&dentry->d_parent->d_lock); |
| 2189 | spin_lock_nested(&target->d_parent->d_lock, |
| 2190 | DENTRY_D_LOCK_NESTED); |
| 2191 | } else { |
| 2192 | spin_lock(&target->d_parent->d_lock); |
| 2193 | spin_lock_nested(&dentry->d_parent->d_lock, |
| 2194 | DENTRY_D_LOCK_NESTED); |
| 2195 | } |
| 2196 | } |
| 2197 | if (target < dentry) { |
| 2198 | spin_lock_nested(&target->d_lock, 2); |
| 2199 | spin_lock_nested(&dentry->d_lock, 3); |
| 2200 | } else { |
| 2201 | spin_lock_nested(&dentry->d_lock, 2); |
| 2202 | spin_lock_nested(&target->d_lock, 3); |
| 2203 | } |
| 2204 | } |
| 2205 | |
| 2206 | static void dentry_unlock_parents_for_move(struct dentry *dentry, |
| 2207 | struct dentry *target) |
| 2208 | { |
| 2209 | if (target->d_parent != dentry->d_parent) |
| 2210 | spin_unlock(&dentry->d_parent->d_lock); |
| 2211 | if (target->d_parent != target) |
| 2212 | spin_unlock(&target->d_parent->d_lock); |
| 2213 | } |
| 2214 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2215 | /* |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2216 | * When switching names, the actual string doesn't strictly have to |
| 2217 | * be preserved in the target - because we're dropping the target |
| 2218 | * anyway. As such, we can just do a simple memcpy() to copy over |
| 2219 | * the new name before we switch. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2220 | * |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2221 | * Note that we have to be a lot more careful about getting the hash |
| 2222 | * switched - we have to switch the hash value properly even if it |
| 2223 | * then no longer matches the actual (corrupted) string of the target. |
| 2224 | * The hash value has to match the hash queue that the dentry is on.. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2225 | */ |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2226 | /* |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2227 | * __d_move - move a dentry |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2228 | * @dentry: entry to move |
| 2229 | * @target: new dentry |
| 2230 | * |
| 2231 | * Update the dcache to reflect the move of a file name. Negative |
Jeff Layton | c46c887 | 2011-07-26 13:33:16 -0400 | [diff] [blame] | 2232 | * dcache entries should not be moved in this way. Caller must hold |
| 2233 | * rename_lock, the i_mutex of the source and target directories, |
| 2234 | * and the sb->s_vfs_rename_mutex if they differ. See lock_rename(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2235 | */ |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2236 | static void __d_move(struct dentry * dentry, struct dentry * target) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2237 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2238 | if (!dentry->d_inode) |
| 2239 | printk(KERN_WARNING "VFS: moving negative dcache entry\n"); |
| 2240 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2241 | BUG_ON(d_ancestor(dentry, target)); |
| 2242 | BUG_ON(d_ancestor(target, dentry)); |
| 2243 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2244 | dentry_lock_for_move(dentry, target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2245 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2246 | write_seqcount_begin(&dentry->d_seq); |
| 2247 | write_seqcount_begin(&target->d_seq); |
| 2248 | |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 2249 | /* __d_drop does write_seqcount_barrier, but they're OK to nest. */ |
| 2250 | |
| 2251 | /* |
| 2252 | * Move the dentry to the target hash queue. Don't bother checking |
| 2253 | * for the same hash queue because of how unlikely it is. |
| 2254 | */ |
| 2255 | __d_drop(dentry); |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 2256 | __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2257 | |
| 2258 | /* Unhash the target: dput() will then get rid of it */ |
| 2259 | __d_drop(target); |
| 2260 | |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2261 | list_del(&dentry->d_u.d_child); |
| 2262 | list_del(&target->d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2263 | |
| 2264 | /* Switch the names.. */ |
| 2265 | switch_names(dentry, target); |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2266 | swap(dentry->d_name.hash, target->d_name.hash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2267 | |
| 2268 | /* ... and switch the parents */ |
| 2269 | if (IS_ROOT(dentry)) { |
| 2270 | dentry->d_parent = target->d_parent; |
| 2271 | target->d_parent = target; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2272 | INIT_LIST_HEAD(&target->d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2273 | } else { |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2274 | swap(dentry->d_parent, target->d_parent); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2275 | |
| 2276 | /* And add them back to the (new) parent lists */ |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2277 | list_add(&target->d_u.d_child, &target->d_parent->d_subdirs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2278 | } |
| 2279 | |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2280 | list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2281 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2282 | write_seqcount_end(&target->d_seq); |
| 2283 | write_seqcount_end(&dentry->d_seq); |
| 2284 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2285 | dentry_unlock_parents_for_move(dentry, target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2286 | spin_unlock(&target->d_lock); |
Nick Piggin | c32ccd8 | 2006-03-25 03:07:09 -0800 | [diff] [blame] | 2287 | fsnotify_d_move(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2288 | spin_unlock(&dentry->d_lock); |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2289 | } |
| 2290 | |
| 2291 | /* |
| 2292 | * d_move - move a dentry |
| 2293 | * @dentry: entry to move |
| 2294 | * @target: new dentry |
| 2295 | * |
| 2296 | * Update the dcache to reflect the move of a file name. Negative |
Jeff Layton | c46c887 | 2011-07-26 13:33:16 -0400 | [diff] [blame] | 2297 | * dcache entries should not be moved in this way. See the locking |
| 2298 | * requirements for __d_move. |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2299 | */ |
| 2300 | void d_move(struct dentry *dentry, struct dentry *target) |
| 2301 | { |
| 2302 | write_seqlock(&rename_lock); |
| 2303 | __d_move(dentry, target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2304 | write_sequnlock(&rename_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2305 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2306 | EXPORT_SYMBOL(d_move); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2307 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2308 | /** |
| 2309 | * d_ancestor - search for an ancestor |
| 2310 | * @p1: ancestor dentry |
| 2311 | * @p2: child dentry |
| 2312 | * |
| 2313 | * Returns the ancestor dentry of p2 which is a child of p1, if p1 is |
| 2314 | * an ancestor of p2, else NULL. |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2315 | */ |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2316 | struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2317 | { |
| 2318 | struct dentry *p; |
| 2319 | |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 2320 | for (p = p2; !IS_ROOT(p); p = p->d_parent) { |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2321 | if (p->d_parent == p1) |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2322 | return p; |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2323 | } |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2324 | return NULL; |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2325 | } |
| 2326 | |
| 2327 | /* |
| 2328 | * This helper attempts to cope with remotely renamed directories |
| 2329 | * |
| 2330 | * It assumes that the caller is already holding |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2331 | * dentry->d_parent->d_inode->i_mutex, inode->i_lock and rename_lock |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2332 | * |
| 2333 | * Note: If ever the locking in lock_rename() changes, then please |
| 2334 | * remember to update this too... |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2335 | */ |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2336 | static struct dentry *__d_unalias(struct inode *inode, |
| 2337 | struct dentry *dentry, struct dentry *alias) |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2338 | { |
| 2339 | struct mutex *m1 = NULL, *m2 = NULL; |
Al Viro | ee3efa9 | 2012-06-08 15:59:33 -0400 | [diff] [blame] | 2340 | struct dentry *ret = ERR_PTR(-EBUSY); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2341 | |
| 2342 | /* If alias and dentry share a parent, then no extra locks required */ |
| 2343 | if (alias->d_parent == dentry->d_parent) |
| 2344 | goto out_unalias; |
| 2345 | |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2346 | /* See lock_rename() */ |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2347 | if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) |
| 2348 | goto out_err; |
| 2349 | m1 = &dentry->d_sb->s_vfs_rename_mutex; |
| 2350 | if (!mutex_trylock(&alias->d_parent->d_inode->i_mutex)) |
| 2351 | goto out_err; |
| 2352 | m2 = &alias->d_parent->d_inode->i_mutex; |
| 2353 | out_unalias: |
Al Viro | ee3efa9 | 2012-06-08 15:59:33 -0400 | [diff] [blame] | 2354 | if (likely(!d_mountpoint(alias))) { |
| 2355 | __d_move(alias, dentry); |
| 2356 | ret = alias; |
| 2357 | } |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2358 | out_err: |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2359 | spin_unlock(&inode->i_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2360 | if (m2) |
| 2361 | mutex_unlock(m2); |
| 2362 | if (m1) |
| 2363 | mutex_unlock(m1); |
| 2364 | return ret; |
| 2365 | } |
| 2366 | |
| 2367 | /* |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2368 | * Prepare an anonymous dentry for life in the superblock's dentry tree as a |
| 2369 | * named dentry in place of the dentry to be replaced. |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2370 | * returns with anon->d_lock held! |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2371 | */ |
| 2372 | static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon) |
| 2373 | { |
Al Viro | 740da42 | 2013-01-30 10:13:38 -0500 | [diff] [blame] | 2374 | struct dentry *dparent; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2375 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2376 | dentry_lock_for_move(anon, dentry); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2377 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2378 | write_seqcount_begin(&dentry->d_seq); |
| 2379 | write_seqcount_begin(&anon->d_seq); |
| 2380 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2381 | dparent = dentry->d_parent; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2382 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2383 | switch_names(dentry, anon); |
| 2384 | swap(dentry->d_name.hash, anon->d_name.hash); |
| 2385 | |
Al Viro | 740da42 | 2013-01-30 10:13:38 -0500 | [diff] [blame] | 2386 | dentry->d_parent = dentry; |
| 2387 | list_del_init(&dentry->d_u.d_child); |
| 2388 | anon->d_parent = dparent; |
Wei Yongjun | 9ed53b1 | 2013-03-12 00:10:50 +0800 | [diff] [blame] | 2389 | list_move(&anon->d_u.d_child, &dparent->d_subdirs); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2390 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2391 | write_seqcount_end(&dentry->d_seq); |
| 2392 | write_seqcount_end(&anon->d_seq); |
| 2393 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2394 | dentry_unlock_parents_for_move(anon, dentry); |
| 2395 | spin_unlock(&dentry->d_lock); |
| 2396 | |
| 2397 | /* anon->d_lock still locked, returns locked */ |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2398 | anon->d_flags &= ~DCACHE_DISCONNECTED; |
| 2399 | } |
| 2400 | |
| 2401 | /** |
| 2402 | * d_materialise_unique - introduce an inode into the tree |
| 2403 | * @dentry: candidate dentry |
| 2404 | * @inode: inode to bind to the dentry, to which aliases may be attached |
| 2405 | * |
| 2406 | * Introduces an dentry into the tree, substituting an extant disconnected |
Jeff Layton | c46c887 | 2011-07-26 13:33:16 -0400 | [diff] [blame] | 2407 | * root directory alias in its place if there is one. Caller must hold the |
| 2408 | * i_mutex of the parent directory. |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2409 | */ |
| 2410 | struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) |
| 2411 | { |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2412 | struct dentry *actual; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2413 | |
| 2414 | BUG_ON(!d_unhashed(dentry)); |
| 2415 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2416 | if (!inode) { |
| 2417 | actual = dentry; |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2418 | __d_instantiate(dentry, NULL); |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2419 | d_rehash(actual); |
| 2420 | goto out_nolock; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2421 | } |
| 2422 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2423 | spin_lock(&inode->i_lock); |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2424 | |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2425 | if (S_ISDIR(inode->i_mode)) { |
| 2426 | struct dentry *alias; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2427 | |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2428 | /* Does an aliased dentry already exist? */ |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 2429 | alias = __d_find_alias(inode, 0); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2430 | if (alias) { |
| 2431 | actual = alias; |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2432 | write_seqlock(&rename_lock); |
| 2433 | |
| 2434 | if (d_ancestor(alias, dentry)) { |
| 2435 | /* Check for loops */ |
| 2436 | actual = ERR_PTR(-ELOOP); |
Michel Lespinasse | b18dafc | 2012-03-26 17:32:44 -0700 | [diff] [blame] | 2437 | spin_unlock(&inode->i_lock); |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2438 | } else if (IS_ROOT(alias)) { |
| 2439 | /* Is this an anonymous mountpoint that we |
| 2440 | * could splice into our tree? */ |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2441 | __d_materialise_dentry(dentry, alias); |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2442 | write_sequnlock(&rename_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2443 | __d_drop(alias); |
| 2444 | goto found; |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2445 | } else { |
| 2446 | /* Nope, but we must(!) avoid directory |
Michel Lespinasse | b18dafc | 2012-03-26 17:32:44 -0700 | [diff] [blame] | 2447 | * aliasing. This drops inode->i_lock */ |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2448 | actual = __d_unalias(inode, dentry, alias); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2449 | } |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2450 | write_sequnlock(&rename_lock); |
David Howells | dd17994 | 2011-08-16 15:31:30 +0100 | [diff] [blame] | 2451 | if (IS_ERR(actual)) { |
| 2452 | if (PTR_ERR(actual) == -ELOOP) |
| 2453 | pr_warn_ratelimited( |
| 2454 | "VFS: Lookup of '%s' in %s %s" |
| 2455 | " would have caused loop\n", |
| 2456 | dentry->d_name.name, |
| 2457 | inode->i_sb->s_type->name, |
| 2458 | inode->i_sb->s_id); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2459 | dput(alias); |
David Howells | dd17994 | 2011-08-16 15:31:30 +0100 | [diff] [blame] | 2460 | } |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2461 | goto out_nolock; |
| 2462 | } |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2463 | } |
| 2464 | |
| 2465 | /* Add a unique reference */ |
| 2466 | actual = __d_instantiate_unique(dentry, inode); |
| 2467 | if (!actual) |
| 2468 | actual = dentry; |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2469 | else |
| 2470 | BUG_ON(!d_unhashed(actual)); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2471 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2472 | spin_lock(&actual->d_lock); |
| 2473 | found: |
| 2474 | _d_rehash(actual); |
| 2475 | spin_unlock(&actual->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2476 | spin_unlock(&inode->i_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2477 | out_nolock: |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2478 | if (actual == dentry) { |
| 2479 | security_d_instantiate(dentry, inode); |
| 2480 | return NULL; |
| 2481 | } |
| 2482 | |
| 2483 | iput(inode); |
| 2484 | return actual; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2485 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2486 | EXPORT_SYMBOL_GPL(d_materialise_unique); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2487 | |
Miklos Szeredi | cdd16d0 | 2008-06-23 18:11:53 +0200 | [diff] [blame] | 2488 | static int prepend(char **buffer, int *buflen, const char *str, int namelen) |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2489 | { |
| 2490 | *buflen -= namelen; |
| 2491 | if (*buflen < 0) |
| 2492 | return -ENAMETOOLONG; |
| 2493 | *buffer -= namelen; |
| 2494 | memcpy(*buffer, str, namelen); |
| 2495 | return 0; |
| 2496 | } |
| 2497 | |
Miklos Szeredi | cdd16d0 | 2008-06-23 18:11:53 +0200 | [diff] [blame] | 2498 | static int prepend_name(char **buffer, int *buflen, struct qstr *name) |
| 2499 | { |
| 2500 | return prepend(buffer, buflen, name->name, name->len); |
| 2501 | } |
| 2502 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2503 | /** |
Randy Dunlap | 208898c | 2010-11-18 15:02:49 -0800 | [diff] [blame] | 2504 | * prepend_path - Prepend path string to a buffer |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2505 | * @path: the dentry/vfsmount to report |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2506 | * @root: root vfsmnt/dentry |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2507 | * @buffer: pointer to the end of the buffer |
| 2508 | * @buflen: pointer to buffer length |
| 2509 | * |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2510 | * Caller holds the rename_lock. |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2511 | */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2512 | static int prepend_path(const struct path *path, |
| 2513 | const struct path *root, |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2514 | char **buffer, int *buflen) |
| 2515 | { |
| 2516 | struct dentry *dentry = path->dentry; |
| 2517 | struct vfsmount *vfsmnt = path->mnt; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 2518 | struct mount *mnt = real_mount(vfsmnt); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2519 | bool slash = false; |
| 2520 | int error = 0; |
| 2521 | |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2522 | while (dentry != root->dentry || vfsmnt != root->mnt) { |
| 2523 | struct dentry * parent; |
| 2524 | |
| 2525 | if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { |
| 2526 | /* Global root? */ |
Al Viro | 676da58 | 2011-11-24 21:47:05 -0500 | [diff] [blame] | 2527 | if (!mnt_has_parent(mnt)) |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2528 | goto global_root; |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 2529 | dentry = mnt->mnt_mountpoint; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 2530 | mnt = mnt->mnt_parent; |
| 2531 | vfsmnt = &mnt->mnt; |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2532 | continue; |
| 2533 | } |
| 2534 | parent = dentry->d_parent; |
| 2535 | prefetch(parent); |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2536 | spin_lock(&dentry->d_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2537 | error = prepend_name(buffer, buflen, &dentry->d_name); |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2538 | spin_unlock(&dentry->d_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2539 | if (!error) |
| 2540 | error = prepend(buffer, buflen, "/", 1); |
| 2541 | if (error) |
| 2542 | break; |
| 2543 | |
| 2544 | slash = true; |
| 2545 | dentry = parent; |
| 2546 | } |
| 2547 | |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2548 | if (!error && !slash) |
| 2549 | error = prepend(buffer, buflen, "/", 1); |
| 2550 | |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2551 | return error; |
| 2552 | |
| 2553 | global_root: |
| 2554 | /* |
| 2555 | * Filesystems needing to implement special "root names" |
| 2556 | * should do so with ->d_dname() |
| 2557 | */ |
| 2558 | if (IS_ROOT(dentry) && |
| 2559 | (dentry->d_name.len != 1 || dentry->d_name.name[0] != '/')) { |
| 2560 | WARN(1, "Root dentry has weird name <%.*s>\n", |
| 2561 | (int) dentry->d_name.len, dentry->d_name.name); |
| 2562 | } |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2563 | if (!slash) |
| 2564 | error = prepend(buffer, buflen, "/", 1); |
| 2565 | if (!error) |
Al Viro | f7a99c5 | 2012-06-09 00:59:08 -0400 | [diff] [blame] | 2566 | error = is_mounted(vfsmnt) ? 1 : 2; |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2567 | return error; |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2568 | } |
| 2569 | |
| 2570 | /** |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 2571 | * __d_path - return the path of a dentry |
Miklos Szeredi | 9d1bc601 | 2008-03-27 13:06:21 +0100 | [diff] [blame] | 2572 | * @path: the dentry/vfsmount to report |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2573 | * @root: root vfsmnt/dentry |
Randy Dunlap | cd956a1 | 2010-08-14 13:05:31 -0700 | [diff] [blame] | 2574 | * @buf: buffer to return value in |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2575 | * @buflen: buffer length |
| 2576 | * |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2577 | * Convert a dentry into an ASCII path name. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2578 | * |
Arjan van de Ven | 52afeef | 2008-12-01 14:35:00 -0800 | [diff] [blame] | 2579 | * Returns a pointer into the buffer or an error code if the |
| 2580 | * path was too long. |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2581 | * |
Christoph Hellwig | be14824 | 2010-10-10 05:36:21 -0400 | [diff] [blame] | 2582 | * "buflen" should be positive. |
Miklos Szeredi | 9d1bc601 | 2008-03-27 13:06:21 +0100 | [diff] [blame] | 2583 | * |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2584 | * If the path is not reachable from the supplied root, return %NULL. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2585 | */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2586 | char *__d_path(const struct path *path, |
| 2587 | const struct path *root, |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2588 | char *buf, int buflen) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2589 | { |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2590 | char *res = buf + buflen; |
| 2591 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2592 | |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2593 | prepend(&res, &buflen, "\0", 1); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2594 | br_read_lock(&vfsmount_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2595 | write_seqlock(&rename_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2596 | error = prepend_path(path, root, &res, &buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2597 | write_sequnlock(&rename_lock); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2598 | br_read_unlock(&vfsmount_lock); |
Christoph Hellwig | be14824 | 2010-10-10 05:36:21 -0400 | [diff] [blame] | 2599 | |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2600 | if (error < 0) |
| 2601 | return ERR_PTR(error); |
| 2602 | if (error > 0) |
| 2603 | return NULL; |
| 2604 | return res; |
| 2605 | } |
| 2606 | |
| 2607 | char *d_absolute_path(const struct path *path, |
| 2608 | char *buf, int buflen) |
| 2609 | { |
| 2610 | struct path root = {}; |
| 2611 | char *res = buf + buflen; |
| 2612 | int error; |
| 2613 | |
| 2614 | prepend(&res, &buflen, "\0", 1); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2615 | br_read_lock(&vfsmount_lock); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2616 | write_seqlock(&rename_lock); |
| 2617 | error = prepend_path(path, &root, &res, &buflen); |
| 2618 | write_sequnlock(&rename_lock); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2619 | br_read_unlock(&vfsmount_lock); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2620 | |
| 2621 | if (error > 1) |
| 2622 | error = -EINVAL; |
| 2623 | if (error < 0) |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2624 | return ERR_PTR(error); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2625 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2626 | } |
| 2627 | |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2628 | /* |
| 2629 | * same as __d_path but appends "(deleted)" for unlinked files. |
| 2630 | */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2631 | static int path_with_deleted(const struct path *path, |
| 2632 | const struct path *root, |
| 2633 | char **buf, int *buflen) |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2634 | { |
| 2635 | prepend(buf, buflen, "\0", 1); |
| 2636 | if (d_unlinked(path->dentry)) { |
| 2637 | int error = prepend(buf, buflen, " (deleted)", 10); |
| 2638 | if (error) |
| 2639 | return error; |
| 2640 | } |
| 2641 | |
| 2642 | return prepend_path(path, root, buf, buflen); |
| 2643 | } |
| 2644 | |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2645 | static int prepend_unreachable(char **buffer, int *buflen) |
| 2646 | { |
| 2647 | return prepend(buffer, buflen, "(unreachable)", 13); |
| 2648 | } |
| 2649 | |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2650 | /** |
| 2651 | * d_path - return the path of a dentry |
Jan Blunck | cf28b48 | 2008-02-14 19:38:44 -0800 | [diff] [blame] | 2652 | * @path: path to report |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2653 | * @buf: buffer to return value in |
| 2654 | * @buflen: buffer length |
| 2655 | * |
| 2656 | * Convert a dentry into an ASCII path name. If the entry has been deleted |
| 2657 | * the string " (deleted)" is appended. Note that this is ambiguous. |
| 2658 | * |
Arjan van de Ven | 52afeef | 2008-12-01 14:35:00 -0800 | [diff] [blame] | 2659 | * Returns a pointer into the buffer or an error code if the path was |
| 2660 | * too long. Note: Callers should use the returned pointer, not the passed |
| 2661 | * in buffer, to use the name! The implementation often starts at an offset |
| 2662 | * into the buffer, and may leave 0 bytes at the start. |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2663 | * |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 2664 | * "buflen" should be positive. |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2665 | */ |
Jan Engelhardt | 20d4fdc | 2008-06-09 16:40:36 -0700 | [diff] [blame] | 2666 | char *d_path(const struct path *path, char *buf, int buflen) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2667 | { |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2668 | char *res = buf + buflen; |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2669 | struct path root; |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2670 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2671 | |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2672 | /* |
| 2673 | * We have various synthetic filesystems that never get mounted. On |
| 2674 | * these filesystems dentries are never used for lookup purposes, and |
| 2675 | * thus don't need to be hashed. They also don't need a name until a |
| 2676 | * user wants to identify the object in /proc/pid/fd/. The little hack |
| 2677 | * below allows us to generate a name for these objects on demand: |
| 2678 | */ |
Jan Blunck | cf28b48 | 2008-02-14 19:38:44 -0800 | [diff] [blame] | 2679 | if (path->dentry->d_op && path->dentry->d_op->d_dname) |
| 2680 | return path->dentry->d_op->d_dname(path->dentry, buf, buflen); |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2681 | |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 2682 | get_fs_root(current->fs, &root); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2683 | br_read_lock(&vfsmount_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2684 | write_seqlock(&rename_lock); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2685 | error = path_with_deleted(path, &root, &res, &buflen); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2686 | write_sequnlock(&rename_lock); |
| 2687 | br_read_unlock(&vfsmount_lock); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2688 | if (error < 0) |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2689 | res = ERR_PTR(error); |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2690 | path_put(&root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2691 | return res; |
| 2692 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2693 | EXPORT_SYMBOL(d_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2694 | |
| 2695 | /* |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2696 | * Helper function for dentry_operations.d_dname() members |
| 2697 | */ |
| 2698 | char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen, |
| 2699 | const char *fmt, ...) |
| 2700 | { |
| 2701 | va_list args; |
| 2702 | char temp[64]; |
| 2703 | int sz; |
| 2704 | |
| 2705 | va_start(args, fmt); |
| 2706 | sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1; |
| 2707 | va_end(args); |
| 2708 | |
| 2709 | if (sz > sizeof(temp) || sz > buflen) |
| 2710 | return ERR_PTR(-ENAMETOOLONG); |
| 2711 | |
| 2712 | buffer += buflen - sz; |
| 2713 | return memcpy(buffer, temp, sz); |
| 2714 | } |
| 2715 | |
Al Viro | 118b230 | 2013-08-24 12:08:17 -0400 | [diff] [blame] | 2716 | char *simple_dname(struct dentry *dentry, char *buffer, int buflen) |
| 2717 | { |
| 2718 | char *end = buffer + buflen; |
| 2719 | /* these dentries are never renamed, so d_lock is not needed */ |
| 2720 | if (prepend(&end, &buflen, " (deleted)", 11) || |
| 2721 | prepend_name(&end, &buflen, &dentry->d_name) || |
| 2722 | prepend(&end, &buflen, "/", 1)) |
| 2723 | end = ERR_PTR(-ENAMETOOLONG); |
| 2724 | return end; |
| 2725 | } |
| 2726 | |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2727 | /* |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2728 | * Write full pathname from the root of the filesystem into the buffer. |
| 2729 | */ |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2730 | static char *__dentry_path(struct dentry *dentry, char *buf, int buflen) |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2731 | { |
| 2732 | char *end = buf + buflen; |
| 2733 | char *retval; |
| 2734 | |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2735 | prepend(&end, &buflen, "\0", 1); |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2736 | if (buflen < 1) |
| 2737 | goto Elong; |
| 2738 | /* Get '/' right */ |
| 2739 | retval = end-1; |
| 2740 | *retval = '/'; |
| 2741 | |
Miklos Szeredi | cdd16d0 | 2008-06-23 18:11:53 +0200 | [diff] [blame] | 2742 | while (!IS_ROOT(dentry)) { |
| 2743 | struct dentry *parent = dentry->d_parent; |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2744 | int error; |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2745 | |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2746 | prefetch(parent); |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2747 | spin_lock(&dentry->d_lock); |
| 2748 | error = prepend_name(&end, &buflen, &dentry->d_name); |
| 2749 | spin_unlock(&dentry->d_lock); |
| 2750 | if (error != 0 || prepend(&end, &buflen, "/", 1) != 0) |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2751 | goto Elong; |
| 2752 | |
| 2753 | retval = end; |
| 2754 | dentry = parent; |
| 2755 | } |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2756 | return retval; |
| 2757 | Elong: |
| 2758 | return ERR_PTR(-ENAMETOOLONG); |
| 2759 | } |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2760 | |
| 2761 | char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen) |
| 2762 | { |
| 2763 | char *retval; |
| 2764 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2765 | write_seqlock(&rename_lock); |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2766 | retval = __dentry_path(dentry, buf, buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2767 | write_sequnlock(&rename_lock); |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2768 | |
| 2769 | return retval; |
| 2770 | } |
| 2771 | EXPORT_SYMBOL(dentry_path_raw); |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2772 | |
| 2773 | char *dentry_path(struct dentry *dentry, char *buf, int buflen) |
| 2774 | { |
| 2775 | char *p = NULL; |
| 2776 | char *retval; |
| 2777 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2778 | write_seqlock(&rename_lock); |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2779 | if (d_unlinked(dentry)) { |
| 2780 | p = buf + buflen; |
| 2781 | if (prepend(&p, &buflen, "//deleted", 10) != 0) |
| 2782 | goto Elong; |
| 2783 | buflen++; |
| 2784 | } |
| 2785 | retval = __dentry_path(dentry, buf, buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2786 | write_sequnlock(&rename_lock); |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2787 | if (!IS_ERR(retval) && p) |
| 2788 | *p = '/'; /* restore '/' overriden with '\0' */ |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2789 | return retval; |
| 2790 | Elong: |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2791 | return ERR_PTR(-ENAMETOOLONG); |
| 2792 | } |
| 2793 | |
| 2794 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2795 | * NOTE! The user-level library version returns a |
| 2796 | * character pointer. The kernel system call just |
| 2797 | * returns the length of the buffer filled (which |
| 2798 | * includes the ending '\0' character), or a negative |
| 2799 | * error value. So libc would do something like |
| 2800 | * |
| 2801 | * char *getcwd(char * buf, size_t size) |
| 2802 | * { |
| 2803 | * int retval; |
| 2804 | * |
| 2805 | * retval = sys_getcwd(buf, size); |
| 2806 | * if (retval >= 0) |
| 2807 | * return buf; |
| 2808 | * errno = -retval; |
| 2809 | * return NULL; |
| 2810 | * } |
| 2811 | */ |
Heiko Carstens | 3cdad42 | 2009-01-14 14:14:22 +0100 | [diff] [blame] | 2812 | SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2813 | { |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2814 | int error; |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2815 | struct path pwd, root; |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2816 | char *page = (char *) __get_free_page(GFP_USER); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2817 | |
| 2818 | if (!page) |
| 2819 | return -ENOMEM; |
| 2820 | |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 2821 | get_fs_root_and_pwd(current->fs, &root, &pwd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2822 | |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2823 | error = -ENOENT; |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2824 | br_read_lock(&vfsmount_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2825 | write_seqlock(&rename_lock); |
Alexey Dobriyan | f3da392 | 2009-05-04 03:32:03 +0400 | [diff] [blame] | 2826 | if (!d_unlinked(pwd.dentry)) { |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2827 | unsigned long len; |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2828 | char *cwd = page + PAGE_SIZE; |
| 2829 | int buflen = PAGE_SIZE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2830 | |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2831 | prepend(&cwd, &buflen, "\0", 1); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2832 | error = prepend_path(&pwd, &root, &cwd, &buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2833 | write_sequnlock(&rename_lock); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2834 | br_read_unlock(&vfsmount_lock); |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2835 | |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2836 | if (error < 0) |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2837 | goto out; |
| 2838 | |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2839 | /* Unreachable from current root */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2840 | if (error > 0) { |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2841 | error = prepend_unreachable(&cwd, &buflen); |
| 2842 | if (error) |
| 2843 | goto out; |
| 2844 | } |
| 2845 | |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2846 | error = -ERANGE; |
| 2847 | len = PAGE_SIZE + page - cwd; |
| 2848 | if (len <= size) { |
| 2849 | error = len; |
| 2850 | if (copy_to_user(buf, cwd, len)) |
| 2851 | error = -EFAULT; |
| 2852 | } |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2853 | } else { |
| 2854 | write_sequnlock(&rename_lock); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2855 | br_read_unlock(&vfsmount_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2856 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2857 | |
| 2858 | out: |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2859 | path_put(&pwd); |
| 2860 | path_put(&root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2861 | free_page((unsigned long) page); |
| 2862 | return error; |
| 2863 | } |
| 2864 | |
| 2865 | /* |
| 2866 | * Test whether new_dentry is a subdirectory of old_dentry. |
| 2867 | * |
| 2868 | * Trivially implemented using the dcache structure |
| 2869 | */ |
| 2870 | |
| 2871 | /** |
| 2872 | * is_subdir - is new dentry a subdirectory of old_dentry |
| 2873 | * @new_dentry: new dentry |
| 2874 | * @old_dentry: old dentry |
| 2875 | * |
| 2876 | * Returns 1 if new_dentry is a subdirectory of the parent (at any depth). |
| 2877 | * Returns 0 otherwise. |
| 2878 | * Caller must ensure that "new_dentry" is pinned before calling is_subdir() |
| 2879 | */ |
| 2880 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2881 | int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2882 | { |
| 2883 | int result; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2884 | unsigned seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2885 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2886 | if (new_dentry == old_dentry) |
| 2887 | return 1; |
| 2888 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2889 | do { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2890 | /* for restarting inner loop in case of seq retry */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2891 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2892 | /* |
| 2893 | * Need rcu_readlock to protect against the d_parent trashing |
| 2894 | * due to d_move |
| 2895 | */ |
| 2896 | rcu_read_lock(); |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2897 | if (d_ancestor(old_dentry, new_dentry)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2898 | result = 1; |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2899 | else |
| 2900 | result = 0; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2901 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2902 | } while (read_seqretry(&rename_lock, seq)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2903 | |
| 2904 | return result; |
| 2905 | } |
| 2906 | |
| 2907 | void d_genocide(struct dentry *root) |
| 2908 | { |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2909 | struct dentry *this_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2910 | struct list_head *next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2911 | unsigned seq; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2912 | int locked = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2913 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2914 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2915 | again: |
| 2916 | this_parent = root; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2917 | spin_lock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2918 | repeat: |
| 2919 | next = this_parent->d_subdirs.next; |
| 2920 | resume: |
| 2921 | while (next != &this_parent->d_subdirs) { |
| 2922 | struct list_head *tmp = next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2923 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2924 | next = tmp->next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2925 | |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 2926 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
| 2927 | if (d_unhashed(dentry) || !dentry->d_inode) { |
| 2928 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2929 | continue; |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 2930 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2931 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2932 | spin_unlock(&this_parent->d_lock); |
| 2933 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2934 | this_parent = dentry; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2935 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2936 | goto repeat; |
| 2937 | } |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2938 | if (!(dentry->d_flags & DCACHE_GENOCIDE)) { |
| 2939 | dentry->d_flags |= DCACHE_GENOCIDE; |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 2940 | dentry->d_lockref.count--; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2941 | } |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 2942 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2943 | } |
| 2944 | if (this_parent != root) { |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 2945 | struct dentry *child = this_parent; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2946 | if (!(this_parent->d_flags & DCACHE_GENOCIDE)) { |
| 2947 | this_parent->d_flags |= DCACHE_GENOCIDE; |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame^] | 2948 | this_parent->d_lockref.count--; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2949 | } |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 2950 | this_parent = try_to_ascend(this_parent, locked, seq); |
| 2951 | if (!this_parent) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2952 | goto rename_retry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2953 | next = child->d_u.d_child.next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2954 | goto resume; |
| 2955 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2956 | spin_unlock(&this_parent->d_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2957 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2958 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2959 | if (locked) |
| 2960 | write_sequnlock(&rename_lock); |
| 2961 | return; |
| 2962 | |
| 2963 | rename_retry: |
Miklos Szeredi | 8110e16 | 2012-09-17 22:23:30 +0200 | [diff] [blame] | 2964 | if (locked) |
| 2965 | goto again; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2966 | locked = 1; |
| 2967 | write_seqlock(&rename_lock); |
| 2968 | goto again; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2969 | } |
| 2970 | |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 2971 | void d_tmpfile(struct dentry *dentry, struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2972 | { |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 2973 | inode_dec_link_count(inode); |
| 2974 | BUG_ON(dentry->d_name.name != dentry->d_iname || |
| 2975 | !hlist_unhashed(&dentry->d_alias) || |
| 2976 | !d_unlinked(dentry)); |
| 2977 | spin_lock(&dentry->d_parent->d_lock); |
| 2978 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
| 2979 | dentry->d_name.len = sprintf(dentry->d_iname, "#%llu", |
| 2980 | (unsigned long long)inode->i_ino); |
| 2981 | spin_unlock(&dentry->d_lock); |
| 2982 | spin_unlock(&dentry->d_parent->d_lock); |
| 2983 | d_instantiate(dentry, inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2984 | } |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 2985 | EXPORT_SYMBOL(d_tmpfile); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2986 | |
| 2987 | static __initdata unsigned long dhash_entries; |
| 2988 | static int __init set_dhash_entries(char *str) |
| 2989 | { |
| 2990 | if (!str) |
| 2991 | return 0; |
| 2992 | dhash_entries = simple_strtoul(str, &str, 0); |
| 2993 | return 1; |
| 2994 | } |
| 2995 | __setup("dhash_entries=", set_dhash_entries); |
| 2996 | |
| 2997 | static void __init dcache_init_early(void) |
| 2998 | { |
Dimitri Sivanich | 074b851 | 2012-02-08 12:39:07 -0800 | [diff] [blame] | 2999 | unsigned int loop; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3000 | |
| 3001 | /* If hashes are distributed across NUMA nodes, defer |
| 3002 | * hash allocation until vmalloc space is available. |
| 3003 | */ |
| 3004 | if (hashdist) |
| 3005 | return; |
| 3006 | |
| 3007 | dentry_hashtable = |
| 3008 | alloc_large_system_hash("Dentry cache", |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 3009 | sizeof(struct hlist_bl_head), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3010 | dhash_entries, |
| 3011 | 13, |
| 3012 | HASH_EARLY, |
| 3013 | &d_hash_shift, |
| 3014 | &d_hash_mask, |
Tim Bird | 31fe62b | 2012-05-23 13:33:35 +0000 | [diff] [blame] | 3015 | 0, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3016 | 0); |
| 3017 | |
Dimitri Sivanich | 074b851 | 2012-02-08 12:39:07 -0800 | [diff] [blame] | 3018 | for (loop = 0; loop < (1U << d_hash_shift); loop++) |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 3019 | INIT_HLIST_BL_HEAD(dentry_hashtable + loop); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3020 | } |
| 3021 | |
Denis Cheng | 74bf17c | 2007-10-16 23:26:30 -0700 | [diff] [blame] | 3022 | static void __init dcache_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3023 | { |
Dimitri Sivanich | 074b851 | 2012-02-08 12:39:07 -0800 | [diff] [blame] | 3024 | unsigned int loop; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3025 | |
| 3026 | /* |
| 3027 | * A constructor could be added for stable state like the lists, |
| 3028 | * but it is probably not worth it because of the cache nature |
| 3029 | * of the dcache. |
| 3030 | */ |
Christoph Lameter | 0a31bd5 | 2007-05-06 14:49:57 -0700 | [diff] [blame] | 3031 | dentry_cache = KMEM_CACHE(dentry, |
| 3032 | SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3033 | |
| 3034 | /* Hash may have been set up in dcache_init_early */ |
| 3035 | if (!hashdist) |
| 3036 | return; |
| 3037 | |
| 3038 | dentry_hashtable = |
| 3039 | alloc_large_system_hash("Dentry cache", |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 3040 | sizeof(struct hlist_bl_head), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3041 | dhash_entries, |
| 3042 | 13, |
| 3043 | 0, |
| 3044 | &d_hash_shift, |
| 3045 | &d_hash_mask, |
Tim Bird | 31fe62b | 2012-05-23 13:33:35 +0000 | [diff] [blame] | 3046 | 0, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3047 | 0); |
| 3048 | |
Dimitri Sivanich | 074b851 | 2012-02-08 12:39:07 -0800 | [diff] [blame] | 3049 | for (loop = 0; loop < (1U << d_hash_shift); loop++) |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 3050 | INIT_HLIST_BL_HEAD(dentry_hashtable + loop); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3051 | } |
| 3052 | |
| 3053 | /* SLAB cache for __getname() consumers */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 3054 | struct kmem_cache *names_cachep __read_mostly; |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 3055 | EXPORT_SYMBOL(names_cachep); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3056 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3057 | EXPORT_SYMBOL(d_genocide); |
| 3058 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3059 | void __init vfs_caches_init_early(void) |
| 3060 | { |
| 3061 | dcache_init_early(); |
| 3062 | inode_init_early(); |
| 3063 | } |
| 3064 | |
| 3065 | void __init vfs_caches_init(unsigned long mempages) |
| 3066 | { |
| 3067 | unsigned long reserve; |
| 3068 | |
| 3069 | /* Base hash sizes on available memory, with a reserve equal to |
| 3070 | 150% of current kernel size */ |
| 3071 | |
| 3072 | reserve = min((mempages - nr_free_pages()) * 3/2, mempages - 1); |
| 3073 | mempages -= reserve; |
| 3074 | |
| 3075 | names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0, |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 3076 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3077 | |
Denis Cheng | 74bf17c | 2007-10-16 23:26:30 -0700 | [diff] [blame] | 3078 | dcache_init(); |
| 3079 | inode_init(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3080 | files_init(mempages); |
Denis Cheng | 74bf17c | 2007-10-16 23:26:30 -0700 | [diff] [blame] | 3081 | mnt_init(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3082 | bdev_cache_init(); |
| 3083 | chrdev_init(); |
| 3084 | } |