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 | { |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 232 | BUG_ON(dentry->d_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) |
| 470 | dentry->d_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: |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 516 | if (dentry->d_count == 1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 517 | might_sleep(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | spin_lock(&dentry->d_lock); |
Nick Piggin | 61f3dee | 2011-01-07 17:49:40 +1100 | [diff] [blame] | 519 | BUG_ON(!dentry->d_count); |
| 520 | if (dentry->d_count > 1) { |
| 521 | dentry->d_count--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | return; |
| 524 | } |
| 525 | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 526 | if (dentry->d_flags & DCACHE_OP_DELETE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 527 | if (dentry->d_op->d_delete(dentry)) |
Nick Piggin | 61f3dee | 2011-01-07 17:49:40 +1100 | [diff] [blame] | 528 | goto kill_it; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 529 | } |
Nick Piggin | 265ac90 | 2010-10-10 05:36:24 -0400 | [diff] [blame] | 530 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 531 | /* Unreachable? Get rid of it */ |
| 532 | if (d_unhashed(dentry)) |
| 533 | goto kill_it; |
Nick Piggin | 265ac90 | 2010-10-10 05:36:24 -0400 | [diff] [blame] | 534 | |
Jeff Layton | 39e3c95 | 2012-11-28 11:30:53 -0500 | [diff] [blame] | 535 | dentry->d_flags |= DCACHE_REFERENCED; |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 536 | dentry_lru_add(dentry); |
Nick Piggin | 265ac90 | 2010-10-10 05:36:24 -0400 | [diff] [blame] | 537 | |
Nick Piggin | 61f3dee | 2011-01-07 17:49:40 +1100 | [diff] [blame] | 538 | dentry->d_count--; |
| 539 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | return; |
| 541 | |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 542 | kill_it: |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 543 | dentry = dentry_kill(dentry, 1); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 544 | if (dentry) |
| 545 | goto repeat; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 546 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 547 | EXPORT_SYMBOL(dput); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | |
| 549 | /** |
| 550 | * d_invalidate - invalidate a dentry |
| 551 | * @dentry: dentry to invalidate |
| 552 | * |
| 553 | * Try to invalidate the dentry if it turns out to be |
| 554 | * possible. If there are other dentries that can be |
| 555 | * reached through this one we can't delete it and we |
| 556 | * return -EBUSY. On success we return 0. |
| 557 | * |
| 558 | * no dcache lock. |
| 559 | */ |
| 560 | |
| 561 | int d_invalidate(struct dentry * dentry) |
| 562 | { |
| 563 | /* |
| 564 | * If it's already been dropped, return OK. |
| 565 | */ |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 566 | spin_lock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 567 | if (d_unhashed(dentry)) { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 568 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 569 | return 0; |
| 570 | } |
| 571 | /* |
| 572 | * Check whether to do a partial shrink_dcache |
| 573 | * to get rid of unused child entries. |
| 574 | */ |
| 575 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 576 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 577 | shrink_dcache_parent(dentry); |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 578 | spin_lock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 579 | } |
| 580 | |
| 581 | /* |
| 582 | * Somebody else still using it? |
| 583 | * |
| 584 | * If it's a directory, we can't drop it |
| 585 | * for fear of somebody re-populating it |
| 586 | * with children (even though dropping it |
| 587 | * would make it unreachable from the root, |
| 588 | * we might still populate it if it was a |
| 589 | * working directory or similar). |
Al Viro | 50e6963 | 2011-11-07 16:39:57 +0000 | [diff] [blame] | 590 | * We also need to leave mountpoints alone, |
| 591 | * directory or not. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | */ |
Al Viro | 50e6963 | 2011-11-07 16:39:57 +0000 | [diff] [blame] | 593 | if (dentry->d_count > 1 && dentry->d_inode) { |
| 594 | if (S_ISDIR(dentry->d_inode->i_mode) || d_mountpoint(dentry)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 595 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 596 | return -EBUSY; |
| 597 | } |
| 598 | } |
| 599 | |
| 600 | __d_drop(dentry); |
| 601 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 602 | return 0; |
| 603 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 604 | EXPORT_SYMBOL(d_invalidate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 606 | /* This must be called with d_lock held */ |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 607 | static inline void __dget_dlock(struct dentry *dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 608 | { |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 609 | dentry->d_count++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | } |
| 611 | |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 612 | static inline void __dget(struct dentry *dentry) |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 613 | { |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 614 | spin_lock(&dentry->d_lock); |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 615 | __dget_dlock(dentry); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 616 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 617 | } |
| 618 | |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 619 | struct dentry *dget_parent(struct dentry *dentry) |
| 620 | { |
| 621 | struct dentry *ret; |
| 622 | |
| 623 | repeat: |
Nick Piggin | a734eb4 | 2011-01-07 17:49:44 +1100 | [diff] [blame] | 624 | /* |
| 625 | * Don't need rcu_dereference because we re-check it was correct under |
| 626 | * the lock. |
| 627 | */ |
| 628 | rcu_read_lock(); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 629 | ret = dentry->d_parent; |
Nick Piggin | a734eb4 | 2011-01-07 17:49:44 +1100 | [diff] [blame] | 630 | spin_lock(&ret->d_lock); |
| 631 | if (unlikely(ret != dentry->d_parent)) { |
| 632 | spin_unlock(&ret->d_lock); |
| 633 | rcu_read_unlock(); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 634 | goto repeat; |
| 635 | } |
Nick Piggin | a734eb4 | 2011-01-07 17:49:44 +1100 | [diff] [blame] | 636 | rcu_read_unlock(); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 637 | BUG_ON(!ret->d_count); |
| 638 | ret->d_count++; |
| 639 | spin_unlock(&ret->d_lock); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 640 | return ret; |
| 641 | } |
| 642 | EXPORT_SYMBOL(dget_parent); |
| 643 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 644 | /** |
| 645 | * d_find_alias - grab a hashed alias of inode |
| 646 | * @inode: inode in question |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 647 | * @want_discon: flag, used by d_splice_alias, to request |
| 648 | * that only a DISCONNECTED alias be returned. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | * |
| 650 | * If inode has a hashed alias, or is a directory and has any alias, |
| 651 | * acquire the reference to alias and return it. Otherwise return NULL. |
| 652 | * Notice that if inode is a directory there can be only one alias and |
| 653 | * it can be unhashed only if it has no children, or if it is the root |
| 654 | * of a filesystem. |
| 655 | * |
NeilBrown | 21c0d8f | 2006-10-04 02:16:16 -0700 | [diff] [blame] | 656 | * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 657 | * any other hashed alias over that one unless @want_discon is set, |
| 658 | * in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | */ |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 660 | static struct dentry *__d_find_alias(struct inode *inode, int want_discon) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 662 | struct dentry *alias, *discon_alias; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 664 | again: |
| 665 | discon_alias = NULL; |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 666 | hlist_for_each_entry(alias, &inode->i_dentry, d_alias) { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 667 | spin_lock(&alias->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 668 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { |
NeilBrown | 21c0d8f | 2006-10-04 02:16:16 -0700 | [diff] [blame] | 669 | if (IS_ROOT(alias) && |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 670 | (alias->d_flags & DCACHE_DISCONNECTED)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | discon_alias = alias; |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 672 | } else if (!want_discon) { |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 673 | __dget_dlock(alias); |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 674 | spin_unlock(&alias->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 675 | return alias; |
| 676 | } |
| 677 | } |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 678 | spin_unlock(&alias->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 679 | } |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 680 | if (discon_alias) { |
| 681 | alias = discon_alias; |
| 682 | spin_lock(&alias->d_lock); |
| 683 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { |
| 684 | if (IS_ROOT(alias) && |
| 685 | (alias->d_flags & DCACHE_DISCONNECTED)) { |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 686 | __dget_dlock(alias); |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 687 | spin_unlock(&alias->d_lock); |
| 688 | return alias; |
| 689 | } |
| 690 | } |
| 691 | spin_unlock(&alias->d_lock); |
| 692 | goto again; |
| 693 | } |
| 694 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 695 | } |
| 696 | |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 697 | struct dentry *d_find_alias(struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 698 | { |
David Howells | 214fda1 | 2006-03-25 03:06:36 -0800 | [diff] [blame] | 699 | struct dentry *de = NULL; |
| 700 | |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 701 | if (!hlist_empty(&inode->i_dentry)) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 702 | spin_lock(&inode->i_lock); |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 703 | de = __d_find_alias(inode, 0); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 704 | spin_unlock(&inode->i_lock); |
David Howells | 214fda1 | 2006-03-25 03:06:36 -0800 | [diff] [blame] | 705 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 706 | return de; |
| 707 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 708 | EXPORT_SYMBOL(d_find_alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | |
| 710 | /* |
| 711 | * Try to kill dentries associated with this inode. |
| 712 | * WARNING: you must own a reference to inode. |
| 713 | */ |
| 714 | void d_prune_aliases(struct inode *inode) |
| 715 | { |
Domen Puncer | 0cdca3f | 2005-09-10 00:27:07 -0700 | [diff] [blame] | 716 | struct dentry *dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 717 | restart: |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 718 | spin_lock(&inode->i_lock); |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 719 | hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 720 | spin_lock(&dentry->d_lock); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 721 | if (!dentry->d_count) { |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 722 | __dget_dlock(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 723 | __d_drop(dentry); |
| 724 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 725 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 726 | dput(dentry); |
| 727 | goto restart; |
| 728 | } |
| 729 | spin_unlock(&dentry->d_lock); |
| 730 | } |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 731 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 732 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 733 | EXPORT_SYMBOL(d_prune_aliases); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 734 | |
| 735 | /* |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 736 | * Try to throw away a dentry - free the inode, dput the parent. |
| 737 | * Requires dentry->d_lock is held, and dentry->d_count == 0. |
| 738 | * Releases dentry->d_lock. |
Andrew Morton | d702ccb | 2006-06-22 14:47:31 -0700 | [diff] [blame] | 739 | * |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 740 | * 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] | 741 | */ |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 742 | static void try_prune_one_dentry(struct dentry *dentry) |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 743 | __releases(dentry->d_lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 744 | { |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 745 | struct dentry *parent; |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 746 | |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 747 | parent = dentry_kill(dentry, 0); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 748 | /* |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 749 | * If dentry_kill returns NULL, we have nothing more to do. |
| 750 | * if it returns the same dentry, trylocks failed. In either |
| 751 | * case, just loop again. |
| 752 | * |
| 753 | * Otherwise, we need to prune ancestors too. This is necessary |
| 754 | * to prevent quadratic behavior of shrink_dcache_parent(), but |
| 755 | * is also expected to be beneficial in reducing dentry cache |
| 756 | * fragmentation. |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 757 | */ |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 758 | if (!parent) |
| 759 | return; |
| 760 | if (parent == dentry) |
| 761 | return; |
| 762 | |
| 763 | /* Prune ancestors. */ |
| 764 | dentry = parent; |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 765 | while (dentry) { |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 766 | spin_lock(&dentry->d_lock); |
Nick Piggin | 89e6054 | 2011-01-07 17:49:45 +1100 | [diff] [blame] | 767 | if (dentry->d_count > 1) { |
| 768 | dentry->d_count--; |
| 769 | spin_unlock(&dentry->d_lock); |
| 770 | return; |
| 771 | } |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 772 | dentry = dentry_kill(dentry, 1); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 773 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 774 | } |
| 775 | |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 776 | static void shrink_dentry_list(struct list_head *list) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 777 | { |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 778 | struct dentry *dentry; |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 779 | |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 780 | rcu_read_lock(); |
| 781 | for (;;) { |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 782 | dentry = list_entry_rcu(list->prev, struct dentry, d_lru); |
| 783 | if (&dentry->d_lru == list) |
| 784 | break; /* empty */ |
| 785 | spin_lock(&dentry->d_lock); |
| 786 | if (dentry != list_entry(list->prev, struct dentry, d_lru)) { |
| 787 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 788 | continue; |
| 789 | } |
| 790 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 791 | /* |
| 792 | * We found an inuse dentry which was not removed from |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 793 | * the LRU because of laziness during lookup. Do not free |
| 794 | * it - just keep it off the LRU list. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 795 | */ |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 796 | if (dentry->d_count) { |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 797 | dentry_lru_del(dentry); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 798 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 799 | continue; |
| 800 | } |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 801 | |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 802 | rcu_read_unlock(); |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 803 | |
| 804 | try_prune_one_dentry(dentry); |
| 805 | |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 806 | rcu_read_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 807 | } |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 808 | rcu_read_unlock(); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 809 | } |
| 810 | |
| 811 | /** |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 812 | * prune_dcache_sb - shrink the dcache |
| 813 | * @sb: superblock |
| 814 | * @count: number of entries to try to free |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 815 | * |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 816 | * Attempt to shrink the superblock dcache LRU by @count entries. This is |
| 817 | * done when we need more memory an called from the superblock shrinker |
| 818 | * function. |
| 819 | * |
| 820 | * This function may fail to free any resources if all the dentries are in |
| 821 | * use. |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 822 | */ |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 823 | void prune_dcache_sb(struct super_block *sb, int count) |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 824 | { |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 825 | struct dentry *dentry; |
| 826 | LIST_HEAD(referenced); |
| 827 | LIST_HEAD(tmp); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 828 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 829 | relock: |
| 830 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 831 | while (!list_empty(&sb->s_dentry_lru)) { |
| 832 | dentry = list_entry(sb->s_dentry_lru.prev, |
| 833 | struct dentry, d_lru); |
| 834 | BUG_ON(dentry->d_sb != sb); |
| 835 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 836 | if (!spin_trylock(&dentry->d_lock)) { |
| 837 | spin_unlock(&dcache_lru_lock); |
| 838 | cpu_relax(); |
| 839 | goto relock; |
| 840 | } |
| 841 | |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 842 | if (dentry->d_flags & DCACHE_REFERENCED) { |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 843 | dentry->d_flags &= ~DCACHE_REFERENCED; |
| 844 | list_move(&dentry->d_lru, &referenced); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 845 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 846 | } else { |
| 847 | list_move_tail(&dentry->d_lru, &tmp); |
Miklos Szeredi | eaf5f90 | 2012-01-10 18:22:25 +0100 | [diff] [blame] | 848 | dentry->d_flags |= DCACHE_SHRINK_LIST; |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 849 | spin_unlock(&dentry->d_lock); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 850 | if (!--count) |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 851 | break; |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 852 | } |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 853 | cond_resched_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 854 | } |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 855 | if (!list_empty(&referenced)) |
| 856 | list_splice(&referenced, &sb->s_dentry_lru); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 857 | spin_unlock(&dcache_lru_lock); |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 858 | |
| 859 | shrink_dentry_list(&tmp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 860 | } |
| 861 | |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 862 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 863 | * shrink_dcache_sb - shrink dcache for a superblock |
| 864 | * @sb: superblock |
| 865 | * |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 866 | * Shrink the dcache for the specified super block. This is used to free |
| 867 | * the dcache before unmounting a file system. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 868 | */ |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 869 | void shrink_dcache_sb(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 870 | { |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 871 | LIST_HEAD(tmp); |
| 872 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 873 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 874 | while (!list_empty(&sb->s_dentry_lru)) { |
| 875 | list_splice_init(&sb->s_dentry_lru, &tmp); |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 876 | spin_unlock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 877 | shrink_dentry_list(&tmp); |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 878 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 879 | } |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 880 | spin_unlock(&dcache_lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 881 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 882 | EXPORT_SYMBOL(shrink_dcache_sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 883 | |
| 884 | /* |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 885 | * destroy a single subtree of dentries for unmount |
| 886 | * - see the comments on shrink_dcache_for_umount() for a description of the |
| 887 | * locking |
| 888 | */ |
| 889 | static void shrink_dcache_for_umount_subtree(struct dentry *dentry) |
| 890 | { |
| 891 | struct dentry *parent; |
| 892 | |
| 893 | BUG_ON(!IS_ROOT(dentry)); |
| 894 | |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 895 | for (;;) { |
| 896 | /* descend to the first leaf in the current subtree */ |
David Howells | 43c1c9c | 2011-06-07 14:09:30 +0100 | [diff] [blame] | 897 | while (!list_empty(&dentry->d_subdirs)) |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 898 | dentry = list_entry(dentry->d_subdirs.next, |
| 899 | struct dentry, d_u.d_child); |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 900 | |
| 901 | /* consume the dentries from this leaf up through its parents |
| 902 | * until we find one with children or run out altogether */ |
| 903 | do { |
| 904 | struct inode *inode; |
| 905 | |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 906 | /* |
Yan, Zheng | 61572bb | 2013-04-15 14:13:21 +0800 | [diff] [blame] | 907 | * inform the fs that this dentry is about to be |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 908 | * unhashed and destroyed. |
| 909 | */ |
Yan, Zheng | 61572bb | 2013-04-15 14:13:21 +0800 | [diff] [blame] | 910 | if (dentry->d_flags & DCACHE_OP_PRUNE) |
| 911 | dentry->d_op->d_prune(dentry); |
| 912 | |
| 913 | dentry_lru_del(dentry); |
David Howells | 43c1c9c | 2011-06-07 14:09:30 +0100 | [diff] [blame] | 914 | __d_shrink(dentry); |
| 915 | |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 916 | if (dentry->d_count != 0) { |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 917 | printk(KERN_ERR |
| 918 | "BUG: Dentry %p{i=%lx,n=%s}" |
| 919 | " still in use (%d)" |
| 920 | " [unmount of %s %s]\n", |
| 921 | dentry, |
| 922 | dentry->d_inode ? |
| 923 | dentry->d_inode->i_ino : 0UL, |
| 924 | dentry->d_name.name, |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 925 | dentry->d_count, |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 926 | dentry->d_sb->s_type->name, |
| 927 | dentry->d_sb->s_id); |
| 928 | BUG(); |
| 929 | } |
| 930 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 931 | if (IS_ROOT(dentry)) { |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 932 | parent = NULL; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 933 | list_del(&dentry->d_u.d_child); |
| 934 | } else { |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 935 | parent = dentry->d_parent; |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 936 | parent->d_count--; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 937 | list_del(&dentry->d_u.d_child); |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 938 | } |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 939 | |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 940 | inode = dentry->d_inode; |
| 941 | if (inode) { |
| 942 | dentry->d_inode = NULL; |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 943 | hlist_del_init(&dentry->d_alias); |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 944 | if (dentry->d_op && dentry->d_op->d_iput) |
| 945 | dentry->d_op->d_iput(dentry, inode); |
| 946 | else |
| 947 | iput(inode); |
| 948 | } |
| 949 | |
| 950 | d_free(dentry); |
| 951 | |
| 952 | /* finished when we fall off the top of the tree, |
| 953 | * otherwise we ascend to the parent and move to the |
| 954 | * next sibling if there is one */ |
| 955 | if (!parent) |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 956 | return; |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 957 | dentry = parent; |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 958 | } while (list_empty(&dentry->d_subdirs)); |
| 959 | |
| 960 | dentry = list_entry(dentry->d_subdirs.next, |
| 961 | struct dentry, d_u.d_child); |
| 962 | } |
| 963 | } |
| 964 | |
| 965 | /* |
| 966 | * destroy the dentries attached to a superblock on unmounting |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 967 | * - we don't need to use dentry->d_lock because: |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 968 | * - the superblock is detached from all mountings and open files, so the |
| 969 | * dentry trees will not be rearranged by the VFS |
| 970 | * - s_umount is write-locked, so the memory pressure shrinker will ignore |
| 971 | * any dentries belonging to this superblock that it comes across |
| 972 | * - the filesystem itself is no longer permitted to rearrange the dentries |
| 973 | * in this superblock |
| 974 | */ |
| 975 | void shrink_dcache_for_umount(struct super_block *sb) |
| 976 | { |
| 977 | struct dentry *dentry; |
| 978 | |
| 979 | if (down_read_trylock(&sb->s_umount)) |
| 980 | BUG(); |
| 981 | |
| 982 | dentry = sb->s_root; |
| 983 | sb->s_root = NULL; |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 984 | dentry->d_count--; |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 985 | shrink_dcache_for_umount_subtree(dentry); |
| 986 | |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 987 | while (!hlist_bl_empty(&sb->s_anon)) { |
| 988 | 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] | 989 | shrink_dcache_for_umount_subtree(dentry); |
| 990 | } |
| 991 | } |
| 992 | |
| 993 | /* |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 994 | * This tries to ascend one level of parenthood, but |
| 995 | * we can race with renaming, so we need to re-check |
| 996 | * the parenthood after dropping the lock and check |
| 997 | * that the sequence number still matches. |
| 998 | */ |
| 999 | static struct dentry *try_to_ascend(struct dentry *old, int locked, unsigned seq) |
| 1000 | { |
| 1001 | struct dentry *new = old->d_parent; |
| 1002 | |
| 1003 | rcu_read_lock(); |
| 1004 | spin_unlock(&old->d_lock); |
| 1005 | spin_lock(&new->d_lock); |
| 1006 | |
| 1007 | /* |
| 1008 | * might go back up the wrong parent if we have had a rename |
| 1009 | * or deletion |
| 1010 | */ |
| 1011 | if (new != old->d_parent || |
Miklos Szeredi | b161dfa6 | 2012-09-17 22:31:38 +0200 | [diff] [blame] | 1012 | (old->d_flags & DCACHE_DENTRY_KILLED) || |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 1013 | (!locked && read_seqretry(&rename_lock, seq))) { |
| 1014 | spin_unlock(&new->d_lock); |
| 1015 | new = NULL; |
| 1016 | } |
| 1017 | rcu_read_unlock(); |
| 1018 | return new; |
| 1019 | } |
| 1020 | |
| 1021 | |
| 1022 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1023 | * Search for at least 1 mount point in the dentry's subdirs. |
| 1024 | * We descend to the next level whenever the d_subdirs |
| 1025 | * list is non-empty and continue searching. |
| 1026 | */ |
| 1027 | |
| 1028 | /** |
| 1029 | * have_submounts - check for mounts over a dentry |
| 1030 | * @parent: dentry to check. |
| 1031 | * |
| 1032 | * Return true if the parent or its subdirectories contain |
| 1033 | * a mount point |
| 1034 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1035 | int have_submounts(struct dentry *parent) |
| 1036 | { |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1037 | struct dentry *this_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1038 | struct list_head *next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1039 | unsigned seq; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1040 | int locked = 0; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1041 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1042 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1043 | again: |
| 1044 | this_parent = parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1045 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1046 | if (d_mountpoint(parent)) |
| 1047 | goto positive; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1048 | spin_lock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1049 | repeat: |
| 1050 | next = this_parent->d_subdirs.next; |
| 1051 | resume: |
| 1052 | while (next != &this_parent->d_subdirs) { |
| 1053 | struct list_head *tmp = next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 1054 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1055 | next = tmp->next; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1056 | |
| 1057 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1058 | /* Have we found a mount point ? */ |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1059 | if (d_mountpoint(dentry)) { |
| 1060 | spin_unlock(&dentry->d_lock); |
| 1061 | spin_unlock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1062 | goto positive; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1063 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1064 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1065 | spin_unlock(&this_parent->d_lock); |
| 1066 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1067 | this_parent = dentry; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1068 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1069 | goto repeat; |
| 1070 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1071 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1072 | } |
| 1073 | /* |
| 1074 | * All done at this level ... ascend and resume the search. |
| 1075 | */ |
| 1076 | if (this_parent != parent) { |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 1077 | struct dentry *child = this_parent; |
| 1078 | this_parent = try_to_ascend(this_parent, locked, seq); |
| 1079 | if (!this_parent) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1080 | goto rename_retry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1081 | next = child->d_u.d_child.next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1082 | goto resume; |
| 1083 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1084 | spin_unlock(&this_parent->d_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1085 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1086 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1087 | if (locked) |
| 1088 | write_sequnlock(&rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1089 | return 0; /* No mount points found in tree */ |
| 1090 | positive: |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1091 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1092 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1093 | if (locked) |
| 1094 | write_sequnlock(&rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1095 | return 1; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1096 | |
| 1097 | rename_retry: |
Miklos Szeredi | 8110e16 | 2012-09-17 22:23:30 +0200 | [diff] [blame] | 1098 | if (locked) |
| 1099 | goto again; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1100 | locked = 1; |
| 1101 | write_seqlock(&rename_lock); |
| 1102 | goto again; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1103 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1104 | EXPORT_SYMBOL(have_submounts); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1105 | |
| 1106 | /* |
J. Bruce Fields | fd51790 | 2012-09-18 16:35:51 -0400 | [diff] [blame] | 1107 | * Search the dentry child list of the specified parent, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1108 | * and move any unused dentries to the end of the unused |
| 1109 | * list for prune_dcache(). We descend to the next level |
| 1110 | * whenever the d_subdirs list is non-empty and continue |
| 1111 | * searching. |
| 1112 | * |
| 1113 | * It returns zero iff there are no unused children, |
| 1114 | * otherwise it returns the number of children moved to |
| 1115 | * the end of the unused list. This may not be the total |
| 1116 | * number of unused children, because select_parent can |
| 1117 | * drop the lock and return early due to latency |
| 1118 | * constraints. |
| 1119 | */ |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 1120 | static int select_parent(struct dentry *parent, struct list_head *dispose) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1121 | { |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1122 | struct dentry *this_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1123 | struct list_head *next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1124 | unsigned seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1125 | int found = 0; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1126 | int locked = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1127 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1128 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1129 | again: |
| 1130 | this_parent = parent; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1131 | spin_lock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1132 | repeat: |
| 1133 | next = this_parent->d_subdirs.next; |
| 1134 | resume: |
| 1135 | while (next != &this_parent->d_subdirs) { |
| 1136 | struct list_head *tmp = next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 1137 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1138 | next = tmp->next; |
| 1139 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1140 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 1141 | |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 1142 | /* |
| 1143 | * move only zero ref count dentries to the dispose list. |
Miklos Szeredi | eaf5f90 | 2012-01-10 18:22:25 +0100 | [diff] [blame] | 1144 | * |
| 1145 | * Those which are presently on the shrink list, being processed |
| 1146 | * by shrink_dentry_list(), shouldn't be moved. Otherwise the |
| 1147 | * loop in shrink_dcache_parent() might not make any progress |
| 1148 | * and loop forever. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1149 | */ |
Miklos Szeredi | eaf5f90 | 2012-01-10 18:22:25 +0100 | [diff] [blame] | 1150 | if (dentry->d_count) { |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 1151 | dentry_lru_del(dentry); |
Miklos Szeredi | eaf5f90 | 2012-01-10 18:22:25 +0100 | [diff] [blame] | 1152 | } else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) { |
| 1153 | dentry_lru_move_list(dentry, dispose); |
| 1154 | dentry->d_flags |= DCACHE_SHRINK_LIST; |
| 1155 | found++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1156 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1157 | /* |
| 1158 | * We can return to the caller if we have found some (this |
| 1159 | * ensures forward progress). We'll be coming back to find |
| 1160 | * the rest. |
| 1161 | */ |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1162 | if (found && need_resched()) { |
| 1163 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1164 | goto out; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1165 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1166 | |
| 1167 | /* |
| 1168 | * Descend a level if the d_subdirs list is non-empty. |
| 1169 | */ |
| 1170 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1171 | spin_unlock(&this_parent->d_lock); |
| 1172 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1173 | this_parent = dentry; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1174 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1175 | goto repeat; |
| 1176 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1177 | |
| 1178 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1179 | } |
| 1180 | /* |
| 1181 | * All done at this level ... ascend and resume the search. |
| 1182 | */ |
| 1183 | if (this_parent != parent) { |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 1184 | struct dentry *child = this_parent; |
| 1185 | this_parent = try_to_ascend(this_parent, locked, seq); |
| 1186 | if (!this_parent) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1187 | goto rename_retry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1188 | next = child->d_u.d_child.next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1189 | goto resume; |
| 1190 | } |
| 1191 | out: |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1192 | spin_unlock(&this_parent->d_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1193 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1194 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1195 | if (locked) |
| 1196 | write_sequnlock(&rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1197 | return found; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1198 | |
| 1199 | rename_retry: |
| 1200 | if (found) |
| 1201 | return found; |
Miklos Szeredi | 8110e16 | 2012-09-17 22:23:30 +0200 | [diff] [blame] | 1202 | if (locked) |
| 1203 | goto again; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1204 | locked = 1; |
| 1205 | write_seqlock(&rename_lock); |
| 1206 | goto again; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1207 | } |
| 1208 | |
| 1209 | /** |
| 1210 | * shrink_dcache_parent - prune dcache |
| 1211 | * @parent: parent of entries to prune |
| 1212 | * |
| 1213 | * Prune the dcache to remove unused children of the parent dentry. |
| 1214 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1215 | void shrink_dcache_parent(struct dentry * parent) |
| 1216 | { |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 1217 | LIST_HEAD(dispose); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1218 | int found; |
| 1219 | |
Greg Thelen | 421348f | 2013-04-30 15:26:48 -0700 | [diff] [blame] | 1220 | while ((found = select_parent(parent, &dispose)) != 0) { |
Dave Chinner | b48f03b | 2011-08-23 18:56:24 +1000 | [diff] [blame] | 1221 | shrink_dentry_list(&dispose); |
Greg Thelen | 421348f | 2013-04-30 15:26:48 -0700 | [diff] [blame] | 1222 | cond_resched(); |
| 1223 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1224 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1225 | EXPORT_SYMBOL(shrink_dcache_parent); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1226 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1227 | /** |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1228 | * __d_alloc - allocate a dcache entry |
| 1229 | * @sb: filesystem it will belong to |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1230 | * @name: qstr of the name |
| 1231 | * |
| 1232 | * Allocates a dentry. It returns %NULL if there is insufficient memory |
| 1233 | * available. On a success the dentry is returned. The name passed in is |
| 1234 | * copied and the copy passed in may be reused after this call. |
| 1235 | */ |
| 1236 | |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1237 | struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1238 | { |
| 1239 | struct dentry *dentry; |
| 1240 | char *dname; |
| 1241 | |
Mel Gorman | e12ba74 | 2007-10-16 01:25:52 -0700 | [diff] [blame] | 1242 | dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1243 | if (!dentry) |
| 1244 | return NULL; |
| 1245 | |
Linus Torvalds | 6326c71 | 2012-05-21 16:14:04 -0700 | [diff] [blame] | 1246 | /* |
| 1247 | * We guarantee that the inline name is always NUL-terminated. |
| 1248 | * This way the memcpy() done by the name switching in rename |
| 1249 | * will still always have a NUL at the end, even if we might |
| 1250 | * be overwriting an internal NUL character |
| 1251 | */ |
| 1252 | dentry->d_iname[DNAME_INLINE_LEN-1] = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1253 | if (name->len > DNAME_INLINE_LEN-1) { |
| 1254 | dname = kmalloc(name->len + 1, GFP_KERNEL); |
| 1255 | if (!dname) { |
| 1256 | kmem_cache_free(dentry_cache, dentry); |
| 1257 | return NULL; |
| 1258 | } |
| 1259 | } else { |
| 1260 | dname = dentry->d_iname; |
| 1261 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1262 | |
| 1263 | dentry->d_name.len = name->len; |
| 1264 | dentry->d_name.hash = name->hash; |
| 1265 | memcpy(dname, name->name, name->len); |
| 1266 | dname[name->len] = 0; |
| 1267 | |
Linus Torvalds | 6326c71 | 2012-05-21 16:14:04 -0700 | [diff] [blame] | 1268 | /* Make sure we always see the terminating NUL character */ |
| 1269 | smp_wmb(); |
| 1270 | dentry->d_name.name = dname; |
| 1271 | |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 1272 | dentry->d_count = 1; |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 1273 | dentry->d_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1274 | spin_lock_init(&dentry->d_lock); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1275 | seqcount_init(&dentry->d_seq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1276 | dentry->d_inode = NULL; |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1277 | dentry->d_parent = dentry; |
| 1278 | dentry->d_sb = sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1279 | dentry->d_op = NULL; |
| 1280 | dentry->d_fsdata = NULL; |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1281 | INIT_HLIST_BL_NODE(&dentry->d_hash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1282 | INIT_LIST_HEAD(&dentry->d_lru); |
| 1283 | INIT_LIST_HEAD(&dentry->d_subdirs); |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1284 | INIT_HLIST_NODE(&dentry->d_alias); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1285 | INIT_LIST_HEAD(&dentry->d_u.d_child); |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1286 | d_set_d_op(dentry, dentry->d_sb->s_d_op); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1287 | |
Nick Piggin | 3e880fb | 2011-01-07 17:49:19 +1100 | [diff] [blame] | 1288 | this_cpu_inc(nr_dentry); |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 1289 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1290 | return dentry; |
| 1291 | } |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1292 | |
| 1293 | /** |
| 1294 | * d_alloc - allocate a dcache entry |
| 1295 | * @parent: parent of entry to allocate |
| 1296 | * @name: qstr of the name |
| 1297 | * |
| 1298 | * Allocates a dentry. It returns %NULL if there is insufficient memory |
| 1299 | * available. On a success the dentry is returned. The name passed in is |
| 1300 | * copied and the copy passed in may be reused after this call. |
| 1301 | */ |
| 1302 | struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) |
| 1303 | { |
| 1304 | struct dentry *dentry = __d_alloc(parent->d_sb, name); |
| 1305 | if (!dentry) |
| 1306 | return NULL; |
| 1307 | |
| 1308 | spin_lock(&parent->d_lock); |
| 1309 | /* |
| 1310 | * don't need child lock because it is not subject |
| 1311 | * to concurrency here |
| 1312 | */ |
| 1313 | __dget_dlock(parent); |
| 1314 | dentry->d_parent = parent; |
| 1315 | list_add(&dentry->d_u.d_child, &parent->d_subdirs); |
| 1316 | spin_unlock(&parent->d_lock); |
| 1317 | |
| 1318 | return dentry; |
| 1319 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1320 | EXPORT_SYMBOL(d_alloc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1321 | |
Nick Piggin | 4b93688 | 2011-01-07 17:50:07 +1100 | [diff] [blame] | 1322 | struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name) |
| 1323 | { |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1324 | struct dentry *dentry = __d_alloc(sb, name); |
| 1325 | if (dentry) |
Nick Piggin | 4b93688 | 2011-01-07 17:50:07 +1100 | [diff] [blame] | 1326 | dentry->d_flags |= DCACHE_DISCONNECTED; |
Nick Piggin | 4b93688 | 2011-01-07 17:50:07 +1100 | [diff] [blame] | 1327 | return dentry; |
| 1328 | } |
| 1329 | EXPORT_SYMBOL(d_alloc_pseudo); |
| 1330 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1331 | struct dentry *d_alloc_name(struct dentry *parent, const char *name) |
| 1332 | { |
| 1333 | struct qstr q; |
| 1334 | |
| 1335 | q.name = name; |
| 1336 | q.len = strlen(name); |
| 1337 | q.hash = full_name_hash(q.name, q.len); |
| 1338 | return d_alloc(parent, &q); |
| 1339 | } |
H Hartley Sweeten | ef26ca9 | 2009-09-29 20:09:42 -0400 | [diff] [blame] | 1340 | EXPORT_SYMBOL(d_alloc_name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1341 | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1342 | void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) |
| 1343 | { |
Linus Torvalds | 6f7f7ca | 2011-01-14 13:26:18 -0800 | [diff] [blame] | 1344 | WARN_ON_ONCE(dentry->d_op); |
| 1345 | WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1346 | DCACHE_OP_COMPARE | |
| 1347 | DCACHE_OP_REVALIDATE | |
Jeff Layton | ecf3d1f | 2013-02-20 11:19:05 -0500 | [diff] [blame] | 1348 | DCACHE_OP_WEAK_REVALIDATE | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1349 | DCACHE_OP_DELETE )); |
| 1350 | dentry->d_op = op; |
| 1351 | if (!op) |
| 1352 | return; |
| 1353 | if (op->d_hash) |
| 1354 | dentry->d_flags |= DCACHE_OP_HASH; |
| 1355 | if (op->d_compare) |
| 1356 | dentry->d_flags |= DCACHE_OP_COMPARE; |
| 1357 | if (op->d_revalidate) |
| 1358 | dentry->d_flags |= DCACHE_OP_REVALIDATE; |
Jeff Layton | ecf3d1f | 2013-02-20 11:19:05 -0500 | [diff] [blame] | 1359 | if (op->d_weak_revalidate) |
| 1360 | dentry->d_flags |= DCACHE_OP_WEAK_REVALIDATE; |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1361 | if (op->d_delete) |
| 1362 | dentry->d_flags |= DCACHE_OP_DELETE; |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 1363 | if (op->d_prune) |
| 1364 | dentry->d_flags |= DCACHE_OP_PRUNE; |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1365 | |
| 1366 | } |
| 1367 | EXPORT_SYMBOL(d_set_d_op); |
| 1368 | |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1369 | static void __d_instantiate(struct dentry *dentry, struct inode *inode) |
| 1370 | { |
Nick Piggin | b23fb0a | 2011-01-07 17:49:35 +1100 | [diff] [blame] | 1371 | spin_lock(&dentry->d_lock); |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1372 | if (inode) { |
| 1373 | if (unlikely(IS_AUTOMOUNT(inode))) |
| 1374 | dentry->d_flags |= DCACHE_NEED_AUTOMOUNT; |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1375 | hlist_add_head(&dentry->d_alias, &inode->i_dentry); |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1376 | } |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1377 | dentry->d_inode = inode; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1378 | dentry_rcuwalk_barrier(dentry); |
Nick Piggin | b23fb0a | 2011-01-07 17:49:35 +1100 | [diff] [blame] | 1379 | spin_unlock(&dentry->d_lock); |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1380 | fsnotify_d_instantiate(dentry, inode); |
| 1381 | } |
| 1382 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1383 | /** |
| 1384 | * d_instantiate - fill in inode information for a dentry |
| 1385 | * @entry: dentry to complete |
| 1386 | * @inode: inode to attach to this dentry |
| 1387 | * |
| 1388 | * Fill in inode information in the entry. |
| 1389 | * |
| 1390 | * This turns negative dentries into productive full members |
| 1391 | * of society. |
| 1392 | * |
| 1393 | * NOTE! This assumes that the inode count has been incremented |
| 1394 | * (or otherwise set) by the caller to indicate that it is now |
| 1395 | * in use by the dcache. |
| 1396 | */ |
| 1397 | |
| 1398 | void d_instantiate(struct dentry *entry, struct inode * inode) |
| 1399 | { |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1400 | BUG_ON(!hlist_unhashed(&entry->d_alias)); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1401 | if (inode) |
| 1402 | spin_lock(&inode->i_lock); |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1403 | __d_instantiate(entry, inode); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1404 | if (inode) |
| 1405 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1406 | security_d_instantiate(entry, inode); |
| 1407 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1408 | EXPORT_SYMBOL(d_instantiate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1409 | |
| 1410 | /** |
| 1411 | * d_instantiate_unique - instantiate a non-aliased dentry |
| 1412 | * @entry: dentry to instantiate |
| 1413 | * @inode: inode to attach to this dentry |
| 1414 | * |
| 1415 | * Fill in inode information in the entry. On success, it returns NULL. |
| 1416 | * If an unhashed alias of "entry" already exists, then we return the |
Oleg Drokin | e866cfa | 2006-01-09 20:52:51 -0800 | [diff] [blame] | 1417 | * aliased dentry instead and drop one reference to inode. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1418 | * |
| 1419 | * Note that in order to avoid conflicts with rename() etc, the caller |
| 1420 | * had better be holding the parent directory semaphore. |
Oleg Drokin | e866cfa | 2006-01-09 20:52:51 -0800 | [diff] [blame] | 1421 | * |
| 1422 | * This also assumes that the inode count has been incremented |
| 1423 | * (or otherwise set) by the caller to indicate that it is now |
| 1424 | * in use by the dcache. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1425 | */ |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1426 | static struct dentry *__d_instantiate_unique(struct dentry *entry, |
| 1427 | struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1428 | { |
| 1429 | struct dentry *alias; |
| 1430 | int len = entry->d_name.len; |
| 1431 | const char *name = entry->d_name.name; |
| 1432 | unsigned int hash = entry->d_name.hash; |
| 1433 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1434 | if (!inode) { |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1435 | __d_instantiate(entry, NULL); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1436 | return NULL; |
| 1437 | } |
| 1438 | |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 1439 | hlist_for_each_entry(alias, &inode->i_dentry, d_alias) { |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 1440 | /* |
| 1441 | * Don't need alias->d_lock here, because aliases with |
| 1442 | * d_parent == entry->d_parent are not subject to name or |
| 1443 | * parent changes, because the parent inode i_mutex is held. |
| 1444 | */ |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1445 | if (alias->d_name.hash != hash) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1446 | continue; |
| 1447 | if (alias->d_parent != entry->d_parent) |
| 1448 | continue; |
Linus Torvalds | ee983e8 | 2012-05-10 12:37:10 -0700 | [diff] [blame] | 1449 | if (alias->d_name.len != len) |
| 1450 | continue; |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1451 | if (dentry_cmp(alias, name, len)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1452 | continue; |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 1453 | __dget(alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1454 | return alias; |
| 1455 | } |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1456 | |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1457 | __d_instantiate(entry, inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1458 | return NULL; |
| 1459 | } |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1460 | |
| 1461 | struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) |
| 1462 | { |
| 1463 | struct dentry *result; |
| 1464 | |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1465 | BUG_ON(!hlist_unhashed(&entry->d_alias)); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1466 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1467 | if (inode) |
| 1468 | spin_lock(&inode->i_lock); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1469 | result = __d_instantiate_unique(entry, inode); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1470 | if (inode) |
| 1471 | spin_unlock(&inode->i_lock); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1472 | |
| 1473 | if (!result) { |
| 1474 | security_d_instantiate(entry, inode); |
| 1475 | return NULL; |
| 1476 | } |
| 1477 | |
| 1478 | BUG_ON(!d_unhashed(result)); |
| 1479 | iput(inode); |
| 1480 | return result; |
| 1481 | } |
| 1482 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1483 | EXPORT_SYMBOL(d_instantiate_unique); |
| 1484 | |
Al Viro | adc0e91 | 2012-01-08 16:49:21 -0500 | [diff] [blame] | 1485 | struct dentry *d_make_root(struct inode *root_inode) |
| 1486 | { |
| 1487 | struct dentry *res = NULL; |
| 1488 | |
| 1489 | if (root_inode) { |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1490 | static const struct qstr name = QSTR_INIT("/", 1); |
Al Viro | adc0e91 | 2012-01-08 16:49:21 -0500 | [diff] [blame] | 1491 | |
| 1492 | res = __d_alloc(root_inode->i_sb, &name); |
| 1493 | if (res) |
| 1494 | d_instantiate(res, root_inode); |
| 1495 | else |
| 1496 | iput(root_inode); |
| 1497 | } |
| 1498 | return res; |
| 1499 | } |
| 1500 | EXPORT_SYMBOL(d_make_root); |
| 1501 | |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1502 | static struct dentry * __d_find_any_alias(struct inode *inode) |
| 1503 | { |
| 1504 | struct dentry *alias; |
| 1505 | |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1506 | if (hlist_empty(&inode->i_dentry)) |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1507 | return NULL; |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1508 | alias = hlist_entry(inode->i_dentry.first, struct dentry, d_alias); |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1509 | __dget(alias); |
| 1510 | return alias; |
| 1511 | } |
| 1512 | |
Sage Weil | 46f72b3 | 2012-01-10 09:04:37 -0800 | [diff] [blame] | 1513 | /** |
| 1514 | * d_find_any_alias - find any alias for a given inode |
| 1515 | * @inode: inode to find an alias for |
| 1516 | * |
| 1517 | * If any aliases exist for the given inode, take and return a |
| 1518 | * reference for one of them. If no aliases exist, return %NULL. |
| 1519 | */ |
| 1520 | struct dentry *d_find_any_alias(struct inode *inode) |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1521 | { |
| 1522 | struct dentry *de; |
| 1523 | |
| 1524 | spin_lock(&inode->i_lock); |
| 1525 | de = __d_find_any_alias(inode); |
| 1526 | spin_unlock(&inode->i_lock); |
| 1527 | return de; |
| 1528 | } |
Sage Weil | 46f72b3 | 2012-01-10 09:04:37 -0800 | [diff] [blame] | 1529 | EXPORT_SYMBOL(d_find_any_alias); |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1530 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1531 | /** |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1532 | * d_obtain_alias - find or allocate a dentry for a given inode |
| 1533 | * @inode: inode to allocate the dentry for |
| 1534 | * |
| 1535 | * Obtain a dentry for an inode resulting from NFS filehandle conversion or |
| 1536 | * similar open by handle operations. The returned dentry may be anonymous, |
| 1537 | * or may have a full name (if the inode was already in the cache). |
| 1538 | * |
| 1539 | * When called on a directory inode, we must ensure that the inode only ever |
| 1540 | * has one dentry. If a dentry is found, that is returned instead of |
| 1541 | * allocating a new one. |
| 1542 | * |
| 1543 | * On successful return, the reference to the inode has been transferred |
Christoph Hellwig | 4400372 | 2008-08-11 15:49:04 +0200 | [diff] [blame] | 1544 | * to the dentry. In case of an error the reference on the inode is released. |
| 1545 | * To make it easier to use in export operations a %NULL or IS_ERR inode may |
| 1546 | * be passed in and will be the error will be propagate to the return value, |
| 1547 | * with a %NULL @inode replaced by ERR_PTR(-ESTALE). |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1548 | */ |
| 1549 | struct dentry *d_obtain_alias(struct inode *inode) |
| 1550 | { |
NeilBrown | b911a6b | 2012-11-08 16:09:37 -0800 | [diff] [blame] | 1551 | static const struct qstr anonstring = QSTR_INIT("/", 1); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1552 | struct dentry *tmp; |
| 1553 | struct dentry *res; |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1554 | |
| 1555 | if (!inode) |
Christoph Hellwig | 4400372 | 2008-08-11 15:49:04 +0200 | [diff] [blame] | 1556 | return ERR_PTR(-ESTALE); |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1557 | if (IS_ERR(inode)) |
| 1558 | return ERR_CAST(inode); |
| 1559 | |
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) |
| 1562 | goto out_iput; |
| 1563 | |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1564 | tmp = __d_alloc(inode->i_sb, &anonstring); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1565 | if (!tmp) { |
| 1566 | res = ERR_PTR(-ENOMEM); |
| 1567 | goto out_iput; |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1568 | } |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 1569 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1570 | spin_lock(&inode->i_lock); |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1571 | res = __d_find_any_alias(inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1572 | if (res) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1573 | spin_unlock(&inode->i_lock); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1574 | dput(tmp); |
| 1575 | goto out_iput; |
| 1576 | } |
| 1577 | |
| 1578 | /* attach a disconnected dentry */ |
| 1579 | spin_lock(&tmp->d_lock); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1580 | tmp->d_inode = inode; |
| 1581 | tmp->d_flags |= DCACHE_DISCONNECTED; |
Al Viro | b3d9b7a | 2012-06-09 13:51:19 -0400 | [diff] [blame] | 1582 | hlist_add_head(&tmp->d_alias, &inode->i_dentry); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 1583 | hlist_bl_lock(&tmp->d_sb->s_anon); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1584 | hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 1585 | hlist_bl_unlock(&tmp->d_sb->s_anon); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1586 | spin_unlock(&tmp->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1587 | spin_unlock(&inode->i_lock); |
Josef Bacik | 24ff666 | 2010-11-18 20:52:55 -0500 | [diff] [blame] | 1588 | security_d_instantiate(tmp, inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1589 | |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1590 | return tmp; |
| 1591 | |
| 1592 | out_iput: |
Josef Bacik | 24ff666 | 2010-11-18 20:52:55 -0500 | [diff] [blame] | 1593 | if (res && !IS_ERR(res)) |
| 1594 | security_d_instantiate(res, inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1595 | iput(inode); |
| 1596 | return res; |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1597 | } |
Benny Halevy | adc4872 | 2009-02-27 14:02:59 -0800 | [diff] [blame] | 1598 | EXPORT_SYMBOL(d_obtain_alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1599 | |
| 1600 | /** |
| 1601 | * d_splice_alias - splice a disconnected dentry into the tree if one exists |
| 1602 | * @inode: the inode which may have a disconnected dentry |
| 1603 | * @dentry: a negative dentry which we want to point to the inode. |
| 1604 | * |
| 1605 | * If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and |
| 1606 | * DCACHE_DISCONNECTED), then d_move that in place of the given dentry |
| 1607 | * and return it, else simply d_add the inode to the dentry and return NULL. |
| 1608 | * |
| 1609 | * This is needed in the lookup routine of any filesystem that is exportable |
| 1610 | * (via knfsd) so that we can build dcache paths to directories effectively. |
| 1611 | * |
| 1612 | * If a dentry was found and moved, then it is returned. Otherwise NULL |
| 1613 | * is returned. This matches the expected return value of ->lookup. |
| 1614 | * |
Steven Whitehouse | 6d4ade9 | 2013-06-14 11:17:15 +0100 | [diff] [blame] | 1615 | * Cluster filesystems may call this function with a negative, hashed dentry. |
| 1616 | * In that case, we know that the inode will be a regular file, and also this |
| 1617 | * will only occur during atomic_open. So we need to check for the dentry |
| 1618 | * being already hashed only in the final case. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1619 | */ |
| 1620 | struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) |
| 1621 | { |
| 1622 | struct dentry *new = NULL; |
| 1623 | |
Al Viro | a904937 | 2011-07-08 21:20:11 -0400 | [diff] [blame] | 1624 | if (IS_ERR(inode)) |
| 1625 | return ERR_CAST(inode); |
| 1626 | |
NeilBrown | 21c0d8f | 2006-10-04 02:16:16 -0700 | [diff] [blame] | 1627 | if (inode && S_ISDIR(inode->i_mode)) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1628 | spin_lock(&inode->i_lock); |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 1629 | new = __d_find_alias(inode, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1630 | if (new) { |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 1631 | BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED)); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1632 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1633 | security_d_instantiate(new, inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1634 | d_move(new, dentry); |
| 1635 | iput(inode); |
| 1636 | } else { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1637 | /* already taking inode->i_lock, so d_add() by hand */ |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1638 | __d_instantiate(dentry, inode); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1639 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1640 | security_d_instantiate(dentry, inode); |
| 1641 | d_rehash(dentry); |
| 1642 | } |
Steven Whitehouse | 6d4ade9 | 2013-06-14 11:17:15 +0100 | [diff] [blame] | 1643 | } else { |
| 1644 | d_instantiate(dentry, inode); |
| 1645 | if (d_unhashed(dentry)) |
| 1646 | d_rehash(dentry); |
| 1647 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1648 | return new; |
| 1649 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1650 | EXPORT_SYMBOL(d_splice_alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1651 | |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1652 | /** |
| 1653 | * d_add_ci - lookup or allocate new dentry with case-exact name |
| 1654 | * @inode: the inode case-insensitive lookup has found |
| 1655 | * @dentry: the negative dentry that was passed to the parent's lookup func |
| 1656 | * @name: the case-exact name to be associated with the returned dentry |
| 1657 | * |
| 1658 | * This is to avoid filling the dcache with case-insensitive names to the |
| 1659 | * same inode, only the actual correct case is stored in the dcache for |
| 1660 | * case-insensitive filesystems. |
| 1661 | * |
| 1662 | * For a case-insensitive lookup match and if the the case-exact dentry |
| 1663 | * already exists in in the dcache, use it and return it. |
| 1664 | * |
| 1665 | * If no entry exists with the exact case name, allocate new dentry with |
| 1666 | * the exact case, and return the spliced entry. |
| 1667 | */ |
Christoph Hellwig | e45b590 | 2008-08-07 23:49:07 +0200 | [diff] [blame] | 1668 | struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1669 | struct qstr *name) |
| 1670 | { |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1671 | struct dentry *found; |
| 1672 | struct dentry *new; |
| 1673 | |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1674 | /* |
| 1675 | * First check if a dentry matching the name already exists, |
| 1676 | * if not go ahead and create it now. |
| 1677 | */ |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1678 | found = d_hash_and_lookup(dentry->d_parent, name); |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1679 | if (unlikely(IS_ERR(found))) |
| 1680 | goto err_out; |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1681 | if (!found) { |
| 1682 | new = d_alloc(dentry->d_parent, name); |
| 1683 | if (!new) { |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1684 | found = ERR_PTR(-ENOMEM); |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1685 | goto err_out; |
| 1686 | } |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1687 | |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1688 | found = d_splice_alias(inode, new); |
| 1689 | if (found) { |
| 1690 | dput(new); |
| 1691 | return found; |
| 1692 | } |
| 1693 | return new; |
| 1694 | } |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1695 | |
| 1696 | /* |
| 1697 | * If a matching dentry exists, and it's not negative use it. |
| 1698 | * |
| 1699 | * Decrement the reference count to balance the iget() done |
| 1700 | * earlier on. |
| 1701 | */ |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1702 | if (found->d_inode) { |
| 1703 | if (unlikely(found->d_inode != inode)) { |
| 1704 | /* This can't happen because bad inodes are unhashed. */ |
| 1705 | BUG_ON(!is_bad_inode(inode)); |
| 1706 | BUG_ON(!is_bad_inode(found->d_inode)); |
| 1707 | } |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1708 | iput(inode); |
| 1709 | return found; |
| 1710 | } |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1711 | |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1712 | /* |
| 1713 | * Negative dentry: instantiate it unless the inode is a directory and |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1714 | * already has a dentry. |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1715 | */ |
Al Viro | 4513d89 | 2011-07-17 10:52:14 -0400 | [diff] [blame] | 1716 | new = d_splice_alias(inode, found); |
| 1717 | if (new) { |
| 1718 | dput(found); |
| 1719 | found = new; |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1720 | } |
Al Viro | 4513d89 | 2011-07-17 10:52:14 -0400 | [diff] [blame] | 1721 | return found; |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1722 | |
| 1723 | err_out: |
| 1724 | iput(inode); |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1725 | return found; |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1726 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1727 | EXPORT_SYMBOL(d_add_ci); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1728 | |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1729 | /* |
| 1730 | * Do the slow-case of the dentry name compare. |
| 1731 | * |
| 1732 | * Unlike the dentry_cmp() function, we need to atomically |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1733 | * load the name and length information, so that the |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1734 | * filesystem can rely on them, and can use the 'name' and |
| 1735 | * 'len' information without worrying about walking off the |
| 1736 | * end of memory etc. |
| 1737 | * |
| 1738 | * Thus the read_seqcount_retry() and the "duplicate" info |
| 1739 | * in arguments (the low-level filesystem should not look |
| 1740 | * at the dentry inode or name contents directly, since |
| 1741 | * rename can change them while we're in RCU mode). |
| 1742 | */ |
| 1743 | enum slow_d_compare { |
| 1744 | D_COMP_OK, |
| 1745 | D_COMP_NOMATCH, |
| 1746 | D_COMP_SEQRETRY, |
| 1747 | }; |
| 1748 | |
| 1749 | static noinline enum slow_d_compare slow_dentry_cmp( |
| 1750 | const struct dentry *parent, |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1751 | struct dentry *dentry, |
| 1752 | unsigned int seq, |
| 1753 | const struct qstr *name) |
| 1754 | { |
| 1755 | int tlen = dentry->d_name.len; |
| 1756 | const char *tname = dentry->d_name.name; |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1757 | |
| 1758 | if (read_seqcount_retry(&dentry->d_seq, seq)) { |
| 1759 | cpu_relax(); |
| 1760 | return D_COMP_SEQRETRY; |
| 1761 | } |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1762 | if (parent->d_op->d_compare(parent, dentry, tlen, tname, name)) |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1763 | return D_COMP_NOMATCH; |
| 1764 | return D_COMP_OK; |
| 1765 | } |
| 1766 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1767 | /** |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1768 | * __d_lookup_rcu - search for a dentry (racy, store-free) |
| 1769 | * @parent: parent dentry |
| 1770 | * @name: qstr of name we wish to find |
Randy Dunlap | 1f1e6e5 | 2012-03-18 21:23:05 -0700 | [diff] [blame] | 1771 | * @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] | 1772 | * Returns: dentry, or NULL |
| 1773 | * |
| 1774 | * __d_lookup_rcu is the dcache lookup function for rcu-walk name |
| 1775 | * resolution (store-free path walking) design described in |
| 1776 | * Documentation/filesystems/path-lookup.txt. |
| 1777 | * |
| 1778 | * This is not to be used outside core vfs. |
| 1779 | * |
| 1780 | * __d_lookup_rcu must only be used in rcu-walk mode, ie. with vfsmount lock |
| 1781 | * held, and rcu_read_lock held. The returned dentry must not be stored into |
| 1782 | * without taking d_lock and checking d_seq sequence count against @seq |
| 1783 | * returned here. |
| 1784 | * |
| 1785 | * A refcount may be taken on the found dentry with the __d_rcu_to_refcount |
| 1786 | * function. |
| 1787 | * |
| 1788 | * Alternatively, __d_lookup_rcu may be called again to look up the child of |
| 1789 | * the returned dentry, so long as its parent's seqlock is checked after the |
| 1790 | * child is looked up. Thus, an interlocking stepping of sequence lock checks |
| 1791 | * is formed, giving integrity down the path walk. |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1792 | * |
| 1793 | * NOTE! The caller *has* to check the resulting dentry against the sequence |
| 1794 | * number we've returned before using any of the resulting dentry state! |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1795 | */ |
Linus Torvalds | 8966be9 | 2012-03-02 14:23:30 -0800 | [diff] [blame] | 1796 | struct dentry *__d_lookup_rcu(const struct dentry *parent, |
| 1797 | const struct qstr *name, |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1798 | unsigned *seqp) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1799 | { |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1800 | u64 hashlen = name->hash_len; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1801 | const unsigned char *str = name->name; |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1802 | struct hlist_bl_head *b = d_hash(parent, hashlen_hash(hashlen)); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1803 | struct hlist_bl_node *node; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1804 | struct dentry *dentry; |
| 1805 | |
| 1806 | /* |
| 1807 | * Note: There is significant duplication with __d_lookup_rcu which is |
| 1808 | * required to prevent single threaded performance regressions |
| 1809 | * especially on architectures where smp_rmb (in seqcounts) are costly. |
| 1810 | * Keep the two functions in sync. |
| 1811 | */ |
| 1812 | |
| 1813 | /* |
| 1814 | * The hash list is protected using RCU. |
| 1815 | * |
| 1816 | * Carefully use d_seq when comparing a candidate dentry, to avoid |
| 1817 | * races with d_move(). |
| 1818 | * |
| 1819 | * It is possible that concurrent renames can mess up our list |
| 1820 | * walk here and result in missing our dentry, resulting in the |
| 1821 | * false-negative result. d_lookup() protects against concurrent |
| 1822 | * renames using rename_lock seqlock. |
| 1823 | * |
Namhyung Kim | b0a4bb8 | 2011-01-22 15:31:32 +0900 | [diff] [blame] | 1824 | * See Documentation/filesystems/path-lookup.txt for more details. |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1825 | */ |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 1826 | hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { |
Linus Torvalds | 8966be9 | 2012-03-02 14:23:30 -0800 | [diff] [blame] | 1827 | unsigned seq; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1828 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1829 | seqretry: |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1830 | /* |
| 1831 | * The dentry sequence count protects us from concurrent |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1832 | * renames, and thus protects parent and name fields. |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1833 | * |
| 1834 | * The caller must perform a seqcount check in order |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1835 | * to do anything useful with the returned dentry. |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1836 | * |
| 1837 | * NOTE! We do a "raw" seqcount_begin here. That means that |
| 1838 | * we don't wait for the sequence count to stabilize if it |
| 1839 | * is in the middle of a sequence change. If we do the slow |
| 1840 | * dentry compare, we will do seqretries until it is stable, |
| 1841 | * and if we end up with a successful lookup, we actually |
| 1842 | * want to exit RCU lookup anyway. |
| 1843 | */ |
| 1844 | seq = raw_seqcount_begin(&dentry->d_seq); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1845 | if (dentry->d_parent != parent) |
| 1846 | continue; |
Linus Torvalds | 2e32180 | 2012-05-21 18:48:10 -0700 | [diff] [blame] | 1847 | if (d_unhashed(dentry)) |
| 1848 | continue; |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1849 | |
| 1850 | if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1851 | if (dentry->d_name.hash != hashlen_hash(hashlen)) |
| 1852 | continue; |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1853 | *seqp = seq; |
| 1854 | switch (slow_dentry_cmp(parent, dentry, seq, name)) { |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1855 | case D_COMP_OK: |
| 1856 | return dentry; |
| 1857 | case D_COMP_NOMATCH: |
| 1858 | continue; |
| 1859 | default: |
| 1860 | goto seqretry; |
| 1861 | } |
| 1862 | } |
| 1863 | |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1864 | if (dentry->d_name.hash_len != hashlen) |
Linus Torvalds | ee983e8 | 2012-05-10 12:37:10 -0700 | [diff] [blame] | 1865 | continue; |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1866 | *seqp = seq; |
Linus Torvalds | 26fe575 | 2012-05-10 13:14:12 -0700 | [diff] [blame] | 1867 | if (!dentry_cmp(dentry, str, hashlen_len(hashlen))) |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1868 | return dentry; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1869 | } |
| 1870 | return NULL; |
| 1871 | } |
| 1872 | |
| 1873 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1874 | * d_lookup - search for a dentry |
| 1875 | * @parent: parent dentry |
| 1876 | * @name: qstr of name we wish to find |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1877 | * Returns: dentry, or NULL |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1878 | * |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1879 | * d_lookup searches the children of the parent dentry for the name in |
| 1880 | * question. If the dentry is found its reference count is incremented and the |
| 1881 | * dentry is returned. The caller must use dput to free the entry when it has |
| 1882 | * finished using it. %NULL is returned if the dentry does not exist. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1883 | */ |
Al Viro | da2d845 | 2013-01-24 18:29:34 -0500 | [diff] [blame] | 1884 | struct dentry *d_lookup(const struct dentry *parent, const struct qstr *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1885 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1886 | struct dentry *dentry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1887 | unsigned seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1888 | |
| 1889 | do { |
| 1890 | seq = read_seqbegin(&rename_lock); |
| 1891 | dentry = __d_lookup(parent, name); |
| 1892 | if (dentry) |
| 1893 | break; |
| 1894 | } while (read_seqretry(&rename_lock, seq)); |
| 1895 | return dentry; |
| 1896 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1897 | EXPORT_SYMBOL(d_lookup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1898 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1899 | /** |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1900 | * __d_lookup - search for a dentry (racy) |
| 1901 | * @parent: parent dentry |
| 1902 | * @name: qstr of name we wish to find |
| 1903 | * Returns: dentry, or NULL |
| 1904 | * |
| 1905 | * __d_lookup is like d_lookup, however it may (rarely) return a |
| 1906 | * false-negative result due to unrelated rename activity. |
| 1907 | * |
| 1908 | * __d_lookup is slightly faster by avoiding rename_lock read seqlock, |
| 1909 | * however it must be used carefully, eg. with a following d_lookup in |
| 1910 | * the case of failure. |
| 1911 | * |
| 1912 | * __d_lookup callers must be commented. |
| 1913 | */ |
Al Viro | a713ca2 | 2013-01-24 18:27:00 -0500 | [diff] [blame] | 1914 | struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1915 | { |
| 1916 | unsigned int len = name->len; |
| 1917 | unsigned int hash = name->hash; |
| 1918 | const unsigned char *str = name->name; |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 1919 | struct hlist_bl_head *b = d_hash(parent, hash); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1920 | struct hlist_bl_node *node; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1921 | struct dentry *found = NULL; |
Paul E. McKenney | 665a758 | 2005-11-07 00:59:17 -0800 | [diff] [blame] | 1922 | struct dentry *dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1923 | |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1924 | /* |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1925 | * Note: There is significant duplication with __d_lookup_rcu which is |
| 1926 | * required to prevent single threaded performance regressions |
| 1927 | * especially on architectures where smp_rmb (in seqcounts) are costly. |
| 1928 | * Keep the two functions in sync. |
| 1929 | */ |
| 1930 | |
| 1931 | /* |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1932 | * The hash list is protected using RCU. |
| 1933 | * |
| 1934 | * Take d_lock when comparing a candidate dentry, to avoid races |
| 1935 | * with d_move(). |
| 1936 | * |
| 1937 | * It is possible that concurrent renames can mess up our list |
| 1938 | * walk here and result in missing our dentry, resulting in the |
| 1939 | * false-negative result. d_lookup() protects against concurrent |
| 1940 | * renames using rename_lock seqlock. |
| 1941 | * |
Namhyung Kim | b0a4bb8 | 2011-01-22 15:31:32 +0900 | [diff] [blame] | 1942 | * See Documentation/filesystems/path-lookup.txt for more details. |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1943 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1944 | rcu_read_lock(); |
| 1945 | |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 1946 | hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1947 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1948 | if (dentry->d_name.hash != hash) |
| 1949 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1950 | |
| 1951 | spin_lock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1952 | if (dentry->d_parent != parent) |
| 1953 | goto next; |
Linus Torvalds | d0185c0 | 2008-09-29 07:42:57 -0700 | [diff] [blame] | 1954 | if (d_unhashed(dentry)) |
| 1955 | goto next; |
| 1956 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1957 | /* |
| 1958 | * It is safe to compare names since d_move() cannot |
| 1959 | * change the qstr (protected by d_lock). |
| 1960 | */ |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1961 | if (parent->d_flags & DCACHE_OP_COMPARE) { |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1962 | int tlen = dentry->d_name.len; |
| 1963 | const char *tname = dentry->d_name.name; |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1964 | if (parent->d_op->d_compare(parent, dentry, tlen, tname, name)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1965 | goto next; |
| 1966 | } else { |
Linus Torvalds | ee983e8 | 2012-05-10 12:37:10 -0700 | [diff] [blame] | 1967 | if (dentry->d_name.len != len) |
| 1968 | goto next; |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1969 | if (dentry_cmp(dentry, str, len)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1970 | goto next; |
| 1971 | } |
| 1972 | |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 1973 | dentry->d_count++; |
Linus Torvalds | d0185c0 | 2008-09-29 07:42:57 -0700 | [diff] [blame] | 1974 | found = dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1975 | spin_unlock(&dentry->d_lock); |
| 1976 | break; |
| 1977 | next: |
| 1978 | spin_unlock(&dentry->d_lock); |
| 1979 | } |
| 1980 | rcu_read_unlock(); |
| 1981 | |
| 1982 | return found; |
| 1983 | } |
| 1984 | |
| 1985 | /** |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 1986 | * d_hash_and_lookup - hash the qstr then search for a dentry |
| 1987 | * @dir: Directory to search in |
| 1988 | * @name: qstr of name we wish to find |
| 1989 | * |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 1990 | * 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] | 1991 | */ |
| 1992 | struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name) |
| 1993 | { |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 1994 | /* |
| 1995 | * Check for a fs-specific hash function. Note that we must |
| 1996 | * calculate the standard hash first, as the d_op->d_hash() |
| 1997 | * routine may choose to leave the hash value unchanged. |
| 1998 | */ |
| 1999 | name->hash = full_name_hash(name->name, name->len); |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 2000 | if (dir->d_flags & DCACHE_OP_HASH) { |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 2001 | int err = dir->d_op->d_hash(dir, name); |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 2002 | if (unlikely(err < 0)) |
| 2003 | return ERR_PTR(err); |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 2004 | } |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 2005 | return d_lookup(dir, name); |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 2006 | } |
Al Viro | 4f522a2 | 2013-02-11 23:20:37 -0500 | [diff] [blame] | 2007 | EXPORT_SYMBOL(d_hash_and_lookup); |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 2008 | |
| 2009 | /** |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 2010 | * d_validate - verify dentry provided from insecure source (deprecated) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2011 | * @dentry: The dentry alleged to be valid child of @dparent |
Randy Dunlap | ff5fdb6 | 2011-01-22 20:16:06 -0800 | [diff] [blame] | 2012 | * @dparent: The parent dentry (known to be valid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2013 | * |
| 2014 | * An insecure source has sent us a dentry, here we verify it and dget() it. |
| 2015 | * This is used by ncpfs in its readdir implementation. |
| 2016 | * Zero is returned in the dentry is invalid. |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 2017 | * |
| 2018 | * 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] | 2019 | */ |
Nick Piggin | d3a23e1 | 2011-01-05 20:01:21 +1100 | [diff] [blame] | 2020 | int d_validate(struct dentry *dentry, struct dentry *dparent) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2021 | { |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 2022 | struct dentry *child; |
Nick Piggin | d3a23e1 | 2011-01-05 20:01:21 +1100 | [diff] [blame] | 2023 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2024 | spin_lock(&dparent->d_lock); |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 2025 | list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) { |
| 2026 | if (dentry == child) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2027 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 2028 | __dget_dlock(dentry); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2029 | spin_unlock(&dentry->d_lock); |
| 2030 | spin_unlock(&dparent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2031 | return 1; |
| 2032 | } |
| 2033 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2034 | spin_unlock(&dparent->d_lock); |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 2035 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2036 | return 0; |
| 2037 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2038 | EXPORT_SYMBOL(d_validate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2039 | |
| 2040 | /* |
| 2041 | * When a file is deleted, we have two options: |
| 2042 | * - turn this dentry into a negative dentry |
| 2043 | * - unhash this dentry and free it. |
| 2044 | * |
| 2045 | * Usually, we want to just turn this into |
| 2046 | * a negative dentry, but if anybody else is |
| 2047 | * currently using the dentry or the inode |
| 2048 | * we can't do that and we fall back on removing |
| 2049 | * it from the hash queues and waiting for |
| 2050 | * it to be deleted later when it has no users |
| 2051 | */ |
| 2052 | |
| 2053 | /** |
| 2054 | * d_delete - delete a dentry |
| 2055 | * @dentry: The dentry to delete |
| 2056 | * |
| 2057 | * Turn the dentry into a negative dentry if possible, otherwise |
| 2058 | * remove it from the hash queues so it can be deleted later |
| 2059 | */ |
| 2060 | |
| 2061 | void d_delete(struct dentry * dentry) |
| 2062 | { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2063 | struct inode *inode; |
John McCutchan | 7a91bf7 | 2005-08-08 13:52:16 -0400 | [diff] [blame] | 2064 | int isdir = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2065 | /* |
| 2066 | * Are we the only user? |
| 2067 | */ |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2068 | again: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2069 | spin_lock(&dentry->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2070 | inode = dentry->d_inode; |
| 2071 | isdir = S_ISDIR(inode->i_mode); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 2072 | if (dentry->d_count == 1) { |
Alan Cox | 1fe0c02 | 2012-09-19 15:49:51 +0100 | [diff] [blame] | 2073 | if (!spin_trylock(&inode->i_lock)) { |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2074 | spin_unlock(&dentry->d_lock); |
| 2075 | cpu_relax(); |
| 2076 | goto again; |
| 2077 | } |
Al Viro | 13e3c5e | 2010-05-21 16:11:04 -0400 | [diff] [blame] | 2078 | dentry->d_flags &= ~DCACHE_CANT_MOUNT; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2079 | dentry_unlink_inode(dentry); |
John McCutchan | 7a91bf7 | 2005-08-08 13:52:16 -0400 | [diff] [blame] | 2080 | fsnotify_nameremove(dentry, isdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2081 | return; |
| 2082 | } |
| 2083 | |
| 2084 | if (!d_unhashed(dentry)) |
| 2085 | __d_drop(dentry); |
| 2086 | |
| 2087 | spin_unlock(&dentry->d_lock); |
John McCutchan | 7a91bf7 | 2005-08-08 13:52:16 -0400 | [diff] [blame] | 2088 | |
| 2089 | fsnotify_nameremove(dentry, isdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2090 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2091 | EXPORT_SYMBOL(d_delete); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2092 | |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 2093 | static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2094 | { |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 2095 | BUG_ON(!d_unhashed(entry)); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 2096 | hlist_bl_lock(b); |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 2097 | entry->d_flags |= DCACHE_RCUACCESS; |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 2098 | hlist_bl_add_head_rcu(&entry->d_hash, b); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 2099 | hlist_bl_unlock(b); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2100 | } |
| 2101 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2102 | static void _d_rehash(struct dentry * entry) |
| 2103 | { |
| 2104 | __d_rehash(entry, d_hash(entry->d_parent, entry->d_name.hash)); |
| 2105 | } |
| 2106 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2107 | /** |
| 2108 | * d_rehash - add an entry back to the hash |
| 2109 | * @entry: dentry to add to the hash |
| 2110 | * |
| 2111 | * Adds a dentry to the hash according to its name. |
| 2112 | */ |
| 2113 | |
| 2114 | void d_rehash(struct dentry * entry) |
| 2115 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2116 | spin_lock(&entry->d_lock); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2117 | _d_rehash(entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2118 | spin_unlock(&entry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2119 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2120 | EXPORT_SYMBOL(d_rehash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2121 | |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2122 | /** |
| 2123 | * dentry_update_name_case - update case insensitive dentry with a new name |
| 2124 | * @dentry: dentry to be updated |
| 2125 | * @name: new name |
| 2126 | * |
| 2127 | * Update a case insensitive dentry with new case of name. |
| 2128 | * |
| 2129 | * dentry must have been returned by d_lookup with name @name. Old and new |
| 2130 | * name lengths must match (ie. no d_compare which allows mismatched name |
| 2131 | * lengths). |
| 2132 | * |
| 2133 | * Parent inode i_mutex must be held over d_lookup and into this call (to |
| 2134 | * keep renames and concurrent inserts, and readdir(2) away). |
| 2135 | */ |
| 2136 | void dentry_update_name_case(struct dentry *dentry, struct qstr *name) |
| 2137 | { |
Linus Torvalds | 7ebfa57 | 2011-04-15 07:34:26 -0700 | [diff] [blame] | 2138 | BUG_ON(!mutex_is_locked(&dentry->d_parent->d_inode->i_mutex)); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2139 | BUG_ON(dentry->d_name.len != name->len); /* d_lookup gives this */ |
| 2140 | |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2141 | spin_lock(&dentry->d_lock); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2142 | write_seqcount_begin(&dentry->d_seq); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2143 | memcpy((unsigned char *)dentry->d_name.name, name->name, name->len); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2144 | write_seqcount_end(&dentry->d_seq); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2145 | spin_unlock(&dentry->d_lock); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2146 | } |
| 2147 | EXPORT_SYMBOL(dentry_update_name_case); |
| 2148 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2149 | static void switch_names(struct dentry *dentry, struct dentry *target) |
| 2150 | { |
| 2151 | if (dname_external(target)) { |
| 2152 | if (dname_external(dentry)) { |
| 2153 | /* |
| 2154 | * Both external: swap the pointers |
| 2155 | */ |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2156 | swap(target->d_name.name, dentry->d_name.name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2157 | } else { |
| 2158 | /* |
| 2159 | * dentry:internal, target:external. Steal target's |
| 2160 | * storage and make target internal. |
| 2161 | */ |
J. Bruce Fields | 321bcf9 | 2007-10-21 16:41:38 -0700 | [diff] [blame] | 2162 | memcpy(target->d_iname, dentry->d_name.name, |
| 2163 | dentry->d_name.len + 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2164 | dentry->d_name.name = target->d_name.name; |
| 2165 | target->d_name.name = target->d_iname; |
| 2166 | } |
| 2167 | } else { |
| 2168 | if (dname_external(dentry)) { |
| 2169 | /* |
| 2170 | * dentry:external, target:internal. Give dentry's |
| 2171 | * storage to target and make dentry internal |
| 2172 | */ |
| 2173 | memcpy(dentry->d_iname, target->d_name.name, |
| 2174 | target->d_name.len + 1); |
| 2175 | target->d_name.name = dentry->d_name.name; |
| 2176 | dentry->d_name.name = dentry->d_iname; |
| 2177 | } else { |
| 2178 | /* |
| 2179 | * Both are internal. Just copy target to dentry |
| 2180 | */ |
| 2181 | memcpy(dentry->d_iname, target->d_name.name, |
| 2182 | target->d_name.len + 1); |
Al Viro | dc711ca | 2008-11-03 15:03:50 -0500 | [diff] [blame] | 2183 | dentry->d_name.len = target->d_name.len; |
| 2184 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2185 | } |
| 2186 | } |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2187 | swap(dentry->d_name.len, target->d_name.len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2188 | } |
| 2189 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2190 | static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target) |
| 2191 | { |
| 2192 | /* |
| 2193 | * XXXX: do we really need to take target->d_lock? |
| 2194 | */ |
| 2195 | if (IS_ROOT(dentry) || dentry->d_parent == target->d_parent) |
| 2196 | spin_lock(&target->d_parent->d_lock); |
| 2197 | else { |
| 2198 | if (d_ancestor(dentry->d_parent, target->d_parent)) { |
| 2199 | spin_lock(&dentry->d_parent->d_lock); |
| 2200 | spin_lock_nested(&target->d_parent->d_lock, |
| 2201 | DENTRY_D_LOCK_NESTED); |
| 2202 | } else { |
| 2203 | spin_lock(&target->d_parent->d_lock); |
| 2204 | spin_lock_nested(&dentry->d_parent->d_lock, |
| 2205 | DENTRY_D_LOCK_NESTED); |
| 2206 | } |
| 2207 | } |
| 2208 | if (target < dentry) { |
| 2209 | spin_lock_nested(&target->d_lock, 2); |
| 2210 | spin_lock_nested(&dentry->d_lock, 3); |
| 2211 | } else { |
| 2212 | spin_lock_nested(&dentry->d_lock, 2); |
| 2213 | spin_lock_nested(&target->d_lock, 3); |
| 2214 | } |
| 2215 | } |
| 2216 | |
| 2217 | static void dentry_unlock_parents_for_move(struct dentry *dentry, |
| 2218 | struct dentry *target) |
| 2219 | { |
| 2220 | if (target->d_parent != dentry->d_parent) |
| 2221 | spin_unlock(&dentry->d_parent->d_lock); |
| 2222 | if (target->d_parent != target) |
| 2223 | spin_unlock(&target->d_parent->d_lock); |
| 2224 | } |
| 2225 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2226 | /* |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2227 | * When switching names, the actual string doesn't strictly have to |
| 2228 | * be preserved in the target - because we're dropping the target |
| 2229 | * anyway. As such, we can just do a simple memcpy() to copy over |
| 2230 | * the new name before we switch. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2231 | * |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2232 | * Note that we have to be a lot more careful about getting the hash |
| 2233 | * switched - we have to switch the hash value properly even if it |
| 2234 | * then no longer matches the actual (corrupted) string of the target. |
| 2235 | * 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] | 2236 | */ |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2237 | /* |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2238 | * __d_move - move a dentry |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2239 | * @dentry: entry to move |
| 2240 | * @target: new dentry |
| 2241 | * |
| 2242 | * Update the dcache to reflect the move of a file name. Negative |
Jeff Layton | c46c887 | 2011-07-26 13:33:16 -0400 | [diff] [blame] | 2243 | * dcache entries should not be moved in this way. Caller must hold |
| 2244 | * rename_lock, the i_mutex of the source and target directories, |
| 2245 | * 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] | 2246 | */ |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2247 | static void __d_move(struct dentry * dentry, struct dentry * target) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2248 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2249 | if (!dentry->d_inode) |
| 2250 | printk(KERN_WARNING "VFS: moving negative dcache entry\n"); |
| 2251 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2252 | BUG_ON(d_ancestor(dentry, target)); |
| 2253 | BUG_ON(d_ancestor(target, dentry)); |
| 2254 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2255 | dentry_lock_for_move(dentry, target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2256 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2257 | write_seqcount_begin(&dentry->d_seq); |
| 2258 | write_seqcount_begin(&target->d_seq); |
| 2259 | |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 2260 | /* __d_drop does write_seqcount_barrier, but they're OK to nest. */ |
| 2261 | |
| 2262 | /* |
| 2263 | * Move the dentry to the target hash queue. Don't bother checking |
| 2264 | * for the same hash queue because of how unlikely it is. |
| 2265 | */ |
| 2266 | __d_drop(dentry); |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 2267 | __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2268 | |
| 2269 | /* Unhash the target: dput() will then get rid of it */ |
| 2270 | __d_drop(target); |
| 2271 | |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2272 | list_del(&dentry->d_u.d_child); |
| 2273 | list_del(&target->d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2274 | |
| 2275 | /* Switch the names.. */ |
| 2276 | switch_names(dentry, target); |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2277 | swap(dentry->d_name.hash, target->d_name.hash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2278 | |
| 2279 | /* ... and switch the parents */ |
| 2280 | if (IS_ROOT(dentry)) { |
| 2281 | dentry->d_parent = target->d_parent; |
| 2282 | target->d_parent = target; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2283 | INIT_LIST_HEAD(&target->d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2284 | } else { |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2285 | swap(dentry->d_parent, target->d_parent); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2286 | |
| 2287 | /* And add them back to the (new) parent lists */ |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2288 | list_add(&target->d_u.d_child, &target->d_parent->d_subdirs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2289 | } |
| 2290 | |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2291 | list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2292 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2293 | write_seqcount_end(&target->d_seq); |
| 2294 | write_seqcount_end(&dentry->d_seq); |
| 2295 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2296 | dentry_unlock_parents_for_move(dentry, target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2297 | spin_unlock(&target->d_lock); |
Nick Piggin | c32ccd8 | 2006-03-25 03:07:09 -0800 | [diff] [blame] | 2298 | fsnotify_d_move(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2299 | spin_unlock(&dentry->d_lock); |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2300 | } |
| 2301 | |
| 2302 | /* |
| 2303 | * d_move - move a dentry |
| 2304 | * @dentry: entry to move |
| 2305 | * @target: new dentry |
| 2306 | * |
| 2307 | * Update the dcache to reflect the move of a file name. Negative |
Jeff Layton | c46c887 | 2011-07-26 13:33:16 -0400 | [diff] [blame] | 2308 | * dcache entries should not be moved in this way. See the locking |
| 2309 | * requirements for __d_move. |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2310 | */ |
| 2311 | void d_move(struct dentry *dentry, struct dentry *target) |
| 2312 | { |
| 2313 | write_seqlock(&rename_lock); |
| 2314 | __d_move(dentry, target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2315 | write_sequnlock(&rename_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2316 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2317 | EXPORT_SYMBOL(d_move); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2318 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2319 | /** |
| 2320 | * d_ancestor - search for an ancestor |
| 2321 | * @p1: ancestor dentry |
| 2322 | * @p2: child dentry |
| 2323 | * |
| 2324 | * Returns the ancestor dentry of p2 which is a child of p1, if p1 is |
| 2325 | * an ancestor of p2, else NULL. |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2326 | */ |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2327 | struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2328 | { |
| 2329 | struct dentry *p; |
| 2330 | |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 2331 | for (p = p2; !IS_ROOT(p); p = p->d_parent) { |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2332 | if (p->d_parent == p1) |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2333 | return p; |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2334 | } |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2335 | return NULL; |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2336 | } |
| 2337 | |
| 2338 | /* |
| 2339 | * This helper attempts to cope with remotely renamed directories |
| 2340 | * |
| 2341 | * It assumes that the caller is already holding |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2342 | * 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] | 2343 | * |
| 2344 | * Note: If ever the locking in lock_rename() changes, then please |
| 2345 | * remember to update this too... |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2346 | */ |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2347 | static struct dentry *__d_unalias(struct inode *inode, |
| 2348 | struct dentry *dentry, struct dentry *alias) |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2349 | { |
| 2350 | struct mutex *m1 = NULL, *m2 = NULL; |
Al Viro | ee3efa9 | 2012-06-08 15:59:33 -0400 | [diff] [blame] | 2351 | struct dentry *ret = ERR_PTR(-EBUSY); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2352 | |
| 2353 | /* If alias and dentry share a parent, then no extra locks required */ |
| 2354 | if (alias->d_parent == dentry->d_parent) |
| 2355 | goto out_unalias; |
| 2356 | |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2357 | /* See lock_rename() */ |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2358 | if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) |
| 2359 | goto out_err; |
| 2360 | m1 = &dentry->d_sb->s_vfs_rename_mutex; |
| 2361 | if (!mutex_trylock(&alias->d_parent->d_inode->i_mutex)) |
| 2362 | goto out_err; |
| 2363 | m2 = &alias->d_parent->d_inode->i_mutex; |
| 2364 | out_unalias: |
Al Viro | ee3efa9 | 2012-06-08 15:59:33 -0400 | [diff] [blame] | 2365 | if (likely(!d_mountpoint(alias))) { |
| 2366 | __d_move(alias, dentry); |
| 2367 | ret = alias; |
| 2368 | } |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2369 | out_err: |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2370 | spin_unlock(&inode->i_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2371 | if (m2) |
| 2372 | mutex_unlock(m2); |
| 2373 | if (m1) |
| 2374 | mutex_unlock(m1); |
| 2375 | return ret; |
| 2376 | } |
| 2377 | |
| 2378 | /* |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2379 | * Prepare an anonymous dentry for life in the superblock's dentry tree as a |
| 2380 | * named dentry in place of the dentry to be replaced. |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2381 | * returns with anon->d_lock held! |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2382 | */ |
| 2383 | static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon) |
| 2384 | { |
Al Viro | 740da42 | 2013-01-30 10:13:38 -0500 | [diff] [blame] | 2385 | struct dentry *dparent; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2386 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2387 | dentry_lock_for_move(anon, dentry); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2388 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2389 | write_seqcount_begin(&dentry->d_seq); |
| 2390 | write_seqcount_begin(&anon->d_seq); |
| 2391 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2392 | dparent = dentry->d_parent; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2393 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2394 | switch_names(dentry, anon); |
| 2395 | swap(dentry->d_name.hash, anon->d_name.hash); |
| 2396 | |
Al Viro | 740da42 | 2013-01-30 10:13:38 -0500 | [diff] [blame] | 2397 | dentry->d_parent = dentry; |
| 2398 | list_del_init(&dentry->d_u.d_child); |
| 2399 | anon->d_parent = dparent; |
Wei Yongjun | 9ed53b1 | 2013-03-12 00:10:50 +0800 | [diff] [blame] | 2400 | list_move(&anon->d_u.d_child, &dparent->d_subdirs); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2401 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2402 | write_seqcount_end(&dentry->d_seq); |
| 2403 | write_seqcount_end(&anon->d_seq); |
| 2404 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2405 | dentry_unlock_parents_for_move(anon, dentry); |
| 2406 | spin_unlock(&dentry->d_lock); |
| 2407 | |
| 2408 | /* anon->d_lock still locked, returns locked */ |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2409 | anon->d_flags &= ~DCACHE_DISCONNECTED; |
| 2410 | } |
| 2411 | |
| 2412 | /** |
| 2413 | * d_materialise_unique - introduce an inode into the tree |
| 2414 | * @dentry: candidate dentry |
| 2415 | * @inode: inode to bind to the dentry, to which aliases may be attached |
| 2416 | * |
| 2417 | * Introduces an dentry into the tree, substituting an extant disconnected |
Jeff Layton | c46c887 | 2011-07-26 13:33:16 -0400 | [diff] [blame] | 2418 | * root directory alias in its place if there is one. Caller must hold the |
| 2419 | * i_mutex of the parent directory. |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2420 | */ |
| 2421 | struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) |
| 2422 | { |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2423 | struct dentry *actual; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2424 | |
| 2425 | BUG_ON(!d_unhashed(dentry)); |
| 2426 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2427 | if (!inode) { |
| 2428 | actual = dentry; |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2429 | __d_instantiate(dentry, NULL); |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2430 | d_rehash(actual); |
| 2431 | goto out_nolock; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2432 | } |
| 2433 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2434 | spin_lock(&inode->i_lock); |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2435 | |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2436 | if (S_ISDIR(inode->i_mode)) { |
| 2437 | struct dentry *alias; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2438 | |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2439 | /* Does an aliased dentry already exist? */ |
Linus Torvalds | 32ba9c3 | 2012-06-08 10:34:03 -0700 | [diff] [blame] | 2440 | alias = __d_find_alias(inode, 0); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2441 | if (alias) { |
| 2442 | actual = alias; |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2443 | write_seqlock(&rename_lock); |
| 2444 | |
| 2445 | if (d_ancestor(alias, dentry)) { |
| 2446 | /* Check for loops */ |
| 2447 | actual = ERR_PTR(-ELOOP); |
Michel Lespinasse | b18dafc | 2012-03-26 17:32:44 -0700 | [diff] [blame] | 2448 | spin_unlock(&inode->i_lock); |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2449 | } else if (IS_ROOT(alias)) { |
| 2450 | /* Is this an anonymous mountpoint that we |
| 2451 | * could splice into our tree? */ |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2452 | __d_materialise_dentry(dentry, alias); |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2453 | write_sequnlock(&rename_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2454 | __d_drop(alias); |
| 2455 | goto found; |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2456 | } else { |
| 2457 | /* Nope, but we must(!) avoid directory |
Michel Lespinasse | b18dafc | 2012-03-26 17:32:44 -0700 | [diff] [blame] | 2458 | * aliasing. This drops inode->i_lock */ |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2459 | actual = __d_unalias(inode, dentry, alias); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2460 | } |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2461 | write_sequnlock(&rename_lock); |
David Howells | dd17994 | 2011-08-16 15:31:30 +0100 | [diff] [blame] | 2462 | if (IS_ERR(actual)) { |
| 2463 | if (PTR_ERR(actual) == -ELOOP) |
| 2464 | pr_warn_ratelimited( |
| 2465 | "VFS: Lookup of '%s' in %s %s" |
| 2466 | " would have caused loop\n", |
| 2467 | dentry->d_name.name, |
| 2468 | inode->i_sb->s_type->name, |
| 2469 | inode->i_sb->s_id); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2470 | dput(alias); |
David Howells | dd17994 | 2011-08-16 15:31:30 +0100 | [diff] [blame] | 2471 | } |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2472 | goto out_nolock; |
| 2473 | } |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2474 | } |
| 2475 | |
| 2476 | /* Add a unique reference */ |
| 2477 | actual = __d_instantiate_unique(dentry, inode); |
| 2478 | if (!actual) |
| 2479 | actual = dentry; |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2480 | else |
| 2481 | BUG_ON(!d_unhashed(actual)); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2482 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2483 | spin_lock(&actual->d_lock); |
| 2484 | found: |
| 2485 | _d_rehash(actual); |
| 2486 | spin_unlock(&actual->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2487 | spin_unlock(&inode->i_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2488 | out_nolock: |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2489 | if (actual == dentry) { |
| 2490 | security_d_instantiate(dentry, inode); |
| 2491 | return NULL; |
| 2492 | } |
| 2493 | |
| 2494 | iput(inode); |
| 2495 | return actual; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2496 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2497 | EXPORT_SYMBOL_GPL(d_materialise_unique); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2498 | |
Miklos Szeredi | cdd16d0 | 2008-06-23 18:11:53 +0200 | [diff] [blame] | 2499 | static int prepend(char **buffer, int *buflen, const char *str, int namelen) |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2500 | { |
| 2501 | *buflen -= namelen; |
| 2502 | if (*buflen < 0) |
| 2503 | return -ENAMETOOLONG; |
| 2504 | *buffer -= namelen; |
| 2505 | memcpy(*buffer, str, namelen); |
| 2506 | return 0; |
| 2507 | } |
| 2508 | |
Miklos Szeredi | cdd16d0 | 2008-06-23 18:11:53 +0200 | [diff] [blame] | 2509 | static int prepend_name(char **buffer, int *buflen, struct qstr *name) |
| 2510 | { |
| 2511 | return prepend(buffer, buflen, name->name, name->len); |
| 2512 | } |
| 2513 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2514 | /** |
Randy Dunlap | 208898c | 2010-11-18 15:02:49 -0800 | [diff] [blame] | 2515 | * prepend_path - Prepend path string to a buffer |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2516 | * @path: the dentry/vfsmount to report |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2517 | * @root: root vfsmnt/dentry |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2518 | * @buffer: pointer to the end of the buffer |
| 2519 | * @buflen: pointer to buffer length |
| 2520 | * |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2521 | * Caller holds the rename_lock. |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2522 | */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2523 | static int prepend_path(const struct path *path, |
| 2524 | const struct path *root, |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2525 | char **buffer, int *buflen) |
| 2526 | { |
| 2527 | struct dentry *dentry = path->dentry; |
| 2528 | struct vfsmount *vfsmnt = path->mnt; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 2529 | struct mount *mnt = real_mount(vfsmnt); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2530 | bool slash = false; |
| 2531 | int error = 0; |
| 2532 | |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2533 | while (dentry != root->dentry || vfsmnt != root->mnt) { |
| 2534 | struct dentry * parent; |
| 2535 | |
| 2536 | if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { |
| 2537 | /* Global root? */ |
Al Viro | 676da58 | 2011-11-24 21:47:05 -0500 | [diff] [blame] | 2538 | if (!mnt_has_parent(mnt)) |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2539 | goto global_root; |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 2540 | dentry = mnt->mnt_mountpoint; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 2541 | mnt = mnt->mnt_parent; |
| 2542 | vfsmnt = &mnt->mnt; |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2543 | continue; |
| 2544 | } |
| 2545 | parent = dentry->d_parent; |
| 2546 | prefetch(parent); |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2547 | spin_lock(&dentry->d_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2548 | error = prepend_name(buffer, buflen, &dentry->d_name); |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2549 | spin_unlock(&dentry->d_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2550 | if (!error) |
| 2551 | error = prepend(buffer, buflen, "/", 1); |
| 2552 | if (error) |
| 2553 | break; |
| 2554 | |
| 2555 | slash = true; |
| 2556 | dentry = parent; |
| 2557 | } |
| 2558 | |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2559 | if (!error && !slash) |
| 2560 | error = prepend(buffer, buflen, "/", 1); |
| 2561 | |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2562 | return error; |
| 2563 | |
| 2564 | global_root: |
| 2565 | /* |
| 2566 | * Filesystems needing to implement special "root names" |
| 2567 | * should do so with ->d_dname() |
| 2568 | */ |
| 2569 | if (IS_ROOT(dentry) && |
| 2570 | (dentry->d_name.len != 1 || dentry->d_name.name[0] != '/')) { |
| 2571 | WARN(1, "Root dentry has weird name <%.*s>\n", |
| 2572 | (int) dentry->d_name.len, dentry->d_name.name); |
| 2573 | } |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2574 | if (!slash) |
| 2575 | error = prepend(buffer, buflen, "/", 1); |
| 2576 | if (!error) |
Al Viro | f7a99c5 | 2012-06-09 00:59:08 -0400 | [diff] [blame] | 2577 | error = is_mounted(vfsmnt) ? 1 : 2; |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2578 | return error; |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2579 | } |
| 2580 | |
| 2581 | /** |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 2582 | * __d_path - return the path of a dentry |
Miklos Szeredi | 9d1bc601 | 2008-03-27 13:06:21 +0100 | [diff] [blame] | 2583 | * @path: the dentry/vfsmount to report |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2584 | * @root: root vfsmnt/dentry |
Randy Dunlap | cd956a1 | 2010-08-14 13:05:31 -0700 | [diff] [blame] | 2585 | * @buf: buffer to return value in |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2586 | * @buflen: buffer length |
| 2587 | * |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2588 | * Convert a dentry into an ASCII path name. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2589 | * |
Arjan van de Ven | 52afeef | 2008-12-01 14:35:00 -0800 | [diff] [blame] | 2590 | * Returns a pointer into the buffer or an error code if the |
| 2591 | * path was too long. |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2592 | * |
Christoph Hellwig | be14824 | 2010-10-10 05:36:21 -0400 | [diff] [blame] | 2593 | * "buflen" should be positive. |
Miklos Szeredi | 9d1bc601 | 2008-03-27 13:06:21 +0100 | [diff] [blame] | 2594 | * |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2595 | * If the path is not reachable from the supplied root, return %NULL. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2596 | */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2597 | char *__d_path(const struct path *path, |
| 2598 | const struct path *root, |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2599 | char *buf, int buflen) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2600 | { |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2601 | char *res = buf + buflen; |
| 2602 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2603 | |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2604 | prepend(&res, &buflen, "\0", 1); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2605 | br_read_lock(&vfsmount_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2606 | write_seqlock(&rename_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2607 | error = prepend_path(path, root, &res, &buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2608 | write_sequnlock(&rename_lock); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2609 | br_read_unlock(&vfsmount_lock); |
Christoph Hellwig | be14824 | 2010-10-10 05:36:21 -0400 | [diff] [blame] | 2610 | |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2611 | if (error < 0) |
| 2612 | return ERR_PTR(error); |
| 2613 | if (error > 0) |
| 2614 | return NULL; |
| 2615 | return res; |
| 2616 | } |
| 2617 | |
| 2618 | char *d_absolute_path(const struct path *path, |
| 2619 | char *buf, int buflen) |
| 2620 | { |
| 2621 | struct path root = {}; |
| 2622 | char *res = buf + buflen; |
| 2623 | int error; |
| 2624 | |
| 2625 | prepend(&res, &buflen, "\0", 1); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2626 | br_read_lock(&vfsmount_lock); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2627 | write_seqlock(&rename_lock); |
| 2628 | error = prepend_path(path, &root, &res, &buflen); |
| 2629 | write_sequnlock(&rename_lock); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2630 | br_read_unlock(&vfsmount_lock); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2631 | |
| 2632 | if (error > 1) |
| 2633 | error = -EINVAL; |
| 2634 | if (error < 0) |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2635 | return ERR_PTR(error); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2636 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2637 | } |
| 2638 | |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2639 | /* |
| 2640 | * same as __d_path but appends "(deleted)" for unlinked files. |
| 2641 | */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2642 | static int path_with_deleted(const struct path *path, |
| 2643 | const struct path *root, |
| 2644 | char **buf, int *buflen) |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2645 | { |
| 2646 | prepend(buf, buflen, "\0", 1); |
| 2647 | if (d_unlinked(path->dentry)) { |
| 2648 | int error = prepend(buf, buflen, " (deleted)", 10); |
| 2649 | if (error) |
| 2650 | return error; |
| 2651 | } |
| 2652 | |
| 2653 | return prepend_path(path, root, buf, buflen); |
| 2654 | } |
| 2655 | |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2656 | static int prepend_unreachable(char **buffer, int *buflen) |
| 2657 | { |
| 2658 | return prepend(buffer, buflen, "(unreachable)", 13); |
| 2659 | } |
| 2660 | |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2661 | /** |
| 2662 | * d_path - return the path of a dentry |
Jan Blunck | cf28b48 | 2008-02-14 19:38:44 -0800 | [diff] [blame] | 2663 | * @path: path to report |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2664 | * @buf: buffer to return value in |
| 2665 | * @buflen: buffer length |
| 2666 | * |
| 2667 | * Convert a dentry into an ASCII path name. If the entry has been deleted |
| 2668 | * the string " (deleted)" is appended. Note that this is ambiguous. |
| 2669 | * |
Arjan van de Ven | 52afeef | 2008-12-01 14:35:00 -0800 | [diff] [blame] | 2670 | * Returns a pointer into the buffer or an error code if the path was |
| 2671 | * too long. Note: Callers should use the returned pointer, not the passed |
| 2672 | * in buffer, to use the name! The implementation often starts at an offset |
| 2673 | * into the buffer, and may leave 0 bytes at the start. |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2674 | * |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 2675 | * "buflen" should be positive. |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2676 | */ |
Jan Engelhardt | 20d4fdc | 2008-06-09 16:40:36 -0700 | [diff] [blame] | 2677 | char *d_path(const struct path *path, char *buf, int buflen) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2678 | { |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2679 | char *res = buf + buflen; |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2680 | struct path root; |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2681 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2682 | |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2683 | /* |
| 2684 | * We have various synthetic filesystems that never get mounted. On |
| 2685 | * these filesystems dentries are never used for lookup purposes, and |
| 2686 | * thus don't need to be hashed. They also don't need a name until a |
| 2687 | * user wants to identify the object in /proc/pid/fd/. The little hack |
| 2688 | * below allows us to generate a name for these objects on demand: |
| 2689 | */ |
Jan Blunck | cf28b48 | 2008-02-14 19:38:44 -0800 | [diff] [blame] | 2690 | if (path->dentry->d_op && path->dentry->d_op->d_dname) |
| 2691 | return path->dentry->d_op->d_dname(path->dentry, buf, buflen); |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2692 | |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 2693 | get_fs_root(current->fs, &root); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2694 | br_read_lock(&vfsmount_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2695 | write_seqlock(&rename_lock); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2696 | error = path_with_deleted(path, &root, &res, &buflen); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2697 | write_sequnlock(&rename_lock); |
| 2698 | br_read_unlock(&vfsmount_lock); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2699 | if (error < 0) |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2700 | res = ERR_PTR(error); |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2701 | path_put(&root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2702 | return res; |
| 2703 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2704 | EXPORT_SYMBOL(d_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2705 | |
| 2706 | /* |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2707 | * Helper function for dentry_operations.d_dname() members |
| 2708 | */ |
| 2709 | char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen, |
| 2710 | const char *fmt, ...) |
| 2711 | { |
| 2712 | va_list args; |
| 2713 | char temp[64]; |
| 2714 | int sz; |
| 2715 | |
| 2716 | va_start(args, fmt); |
| 2717 | sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1; |
| 2718 | va_end(args); |
| 2719 | |
| 2720 | if (sz > sizeof(temp) || sz > buflen) |
| 2721 | return ERR_PTR(-ENAMETOOLONG); |
| 2722 | |
| 2723 | buffer += buflen - sz; |
| 2724 | return memcpy(buffer, temp, sz); |
| 2725 | } |
| 2726 | |
Al Viro | 118b230 | 2013-08-24 12:08:17 -0400 | [diff] [blame] | 2727 | char *simple_dname(struct dentry *dentry, char *buffer, int buflen) |
| 2728 | { |
| 2729 | char *end = buffer + buflen; |
| 2730 | /* these dentries are never renamed, so d_lock is not needed */ |
| 2731 | if (prepend(&end, &buflen, " (deleted)", 11) || |
| 2732 | prepend_name(&end, &buflen, &dentry->d_name) || |
| 2733 | prepend(&end, &buflen, "/", 1)) |
| 2734 | end = ERR_PTR(-ENAMETOOLONG); |
| 2735 | return end; |
| 2736 | } |
| 2737 | |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2738 | /* |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2739 | * Write full pathname from the root of the filesystem into the buffer. |
| 2740 | */ |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2741 | static char *__dentry_path(struct dentry *dentry, char *buf, int buflen) |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2742 | { |
| 2743 | char *end = buf + buflen; |
| 2744 | char *retval; |
| 2745 | |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2746 | prepend(&end, &buflen, "\0", 1); |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2747 | if (buflen < 1) |
| 2748 | goto Elong; |
| 2749 | /* Get '/' right */ |
| 2750 | retval = end-1; |
| 2751 | *retval = '/'; |
| 2752 | |
Miklos Szeredi | cdd16d0 | 2008-06-23 18:11:53 +0200 | [diff] [blame] | 2753 | while (!IS_ROOT(dentry)) { |
| 2754 | struct dentry *parent = dentry->d_parent; |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2755 | int error; |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2756 | |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2757 | prefetch(parent); |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2758 | spin_lock(&dentry->d_lock); |
| 2759 | error = prepend_name(&end, &buflen, &dentry->d_name); |
| 2760 | spin_unlock(&dentry->d_lock); |
| 2761 | if (error != 0 || prepend(&end, &buflen, "/", 1) != 0) |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2762 | goto Elong; |
| 2763 | |
| 2764 | retval = end; |
| 2765 | dentry = parent; |
| 2766 | } |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2767 | return retval; |
| 2768 | Elong: |
| 2769 | return ERR_PTR(-ENAMETOOLONG); |
| 2770 | } |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2771 | |
| 2772 | char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen) |
| 2773 | { |
| 2774 | char *retval; |
| 2775 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2776 | write_seqlock(&rename_lock); |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2777 | retval = __dentry_path(dentry, buf, buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2778 | write_sequnlock(&rename_lock); |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2779 | |
| 2780 | return retval; |
| 2781 | } |
| 2782 | EXPORT_SYMBOL(dentry_path_raw); |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2783 | |
| 2784 | char *dentry_path(struct dentry *dentry, char *buf, int buflen) |
| 2785 | { |
| 2786 | char *p = NULL; |
| 2787 | char *retval; |
| 2788 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2789 | write_seqlock(&rename_lock); |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2790 | if (d_unlinked(dentry)) { |
| 2791 | p = buf + buflen; |
| 2792 | if (prepend(&p, &buflen, "//deleted", 10) != 0) |
| 2793 | goto Elong; |
| 2794 | buflen++; |
| 2795 | } |
| 2796 | retval = __dentry_path(dentry, buf, buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2797 | write_sequnlock(&rename_lock); |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2798 | if (!IS_ERR(retval) && p) |
| 2799 | *p = '/'; /* restore '/' overriden with '\0' */ |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2800 | return retval; |
| 2801 | Elong: |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2802 | return ERR_PTR(-ENAMETOOLONG); |
| 2803 | } |
| 2804 | |
| 2805 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2806 | * NOTE! The user-level library version returns a |
| 2807 | * character pointer. The kernel system call just |
| 2808 | * returns the length of the buffer filled (which |
| 2809 | * includes the ending '\0' character), or a negative |
| 2810 | * error value. So libc would do something like |
| 2811 | * |
| 2812 | * char *getcwd(char * buf, size_t size) |
| 2813 | * { |
| 2814 | * int retval; |
| 2815 | * |
| 2816 | * retval = sys_getcwd(buf, size); |
| 2817 | * if (retval >= 0) |
| 2818 | * return buf; |
| 2819 | * errno = -retval; |
| 2820 | * return NULL; |
| 2821 | * } |
| 2822 | */ |
Heiko Carstens | 3cdad42 | 2009-01-14 14:14:22 +0100 | [diff] [blame] | 2823 | SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2824 | { |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2825 | int error; |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2826 | struct path pwd, root; |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2827 | char *page = (char *) __get_free_page(GFP_USER); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2828 | |
| 2829 | if (!page) |
| 2830 | return -ENOMEM; |
| 2831 | |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 2832 | get_fs_root_and_pwd(current->fs, &root, &pwd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2833 | |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2834 | error = -ENOENT; |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2835 | br_read_lock(&vfsmount_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2836 | write_seqlock(&rename_lock); |
Alexey Dobriyan | f3da392 | 2009-05-04 03:32:03 +0400 | [diff] [blame] | 2837 | if (!d_unlinked(pwd.dentry)) { |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2838 | unsigned long len; |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2839 | char *cwd = page + PAGE_SIZE; |
| 2840 | int buflen = PAGE_SIZE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2841 | |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2842 | prepend(&cwd, &buflen, "\0", 1); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2843 | error = prepend_path(&pwd, &root, &cwd, &buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2844 | write_sequnlock(&rename_lock); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2845 | br_read_unlock(&vfsmount_lock); |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2846 | |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2847 | if (error < 0) |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2848 | goto out; |
| 2849 | |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2850 | /* Unreachable from current root */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2851 | if (error > 0) { |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2852 | error = prepend_unreachable(&cwd, &buflen); |
| 2853 | if (error) |
| 2854 | goto out; |
| 2855 | } |
| 2856 | |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2857 | error = -ERANGE; |
| 2858 | len = PAGE_SIZE + page - cwd; |
| 2859 | if (len <= size) { |
| 2860 | error = len; |
| 2861 | if (copy_to_user(buf, cwd, len)) |
| 2862 | error = -EFAULT; |
| 2863 | } |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2864 | } else { |
| 2865 | write_sequnlock(&rename_lock); |
Al Viro | 7ea600b | 2013-03-26 18:25:57 -0400 | [diff] [blame] | 2866 | br_read_unlock(&vfsmount_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2867 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2868 | |
| 2869 | out: |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2870 | path_put(&pwd); |
| 2871 | path_put(&root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2872 | free_page((unsigned long) page); |
| 2873 | return error; |
| 2874 | } |
| 2875 | |
| 2876 | /* |
| 2877 | * Test whether new_dentry is a subdirectory of old_dentry. |
| 2878 | * |
| 2879 | * Trivially implemented using the dcache structure |
| 2880 | */ |
| 2881 | |
| 2882 | /** |
| 2883 | * is_subdir - is new dentry a subdirectory of old_dentry |
| 2884 | * @new_dentry: new dentry |
| 2885 | * @old_dentry: old dentry |
| 2886 | * |
| 2887 | * Returns 1 if new_dentry is a subdirectory of the parent (at any depth). |
| 2888 | * Returns 0 otherwise. |
| 2889 | * Caller must ensure that "new_dentry" is pinned before calling is_subdir() |
| 2890 | */ |
| 2891 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2892 | int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2893 | { |
| 2894 | int result; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2895 | unsigned seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2896 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2897 | if (new_dentry == old_dentry) |
| 2898 | return 1; |
| 2899 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2900 | do { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2901 | /* for restarting inner loop in case of seq retry */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2902 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2903 | /* |
| 2904 | * Need rcu_readlock to protect against the d_parent trashing |
| 2905 | * due to d_move |
| 2906 | */ |
| 2907 | rcu_read_lock(); |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2908 | if (d_ancestor(old_dentry, new_dentry)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2909 | result = 1; |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2910 | else |
| 2911 | result = 0; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2912 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2913 | } while (read_seqretry(&rename_lock, seq)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2914 | |
| 2915 | return result; |
| 2916 | } |
| 2917 | |
| 2918 | void d_genocide(struct dentry *root) |
| 2919 | { |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2920 | struct dentry *this_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2921 | struct list_head *next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2922 | unsigned seq; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2923 | int locked = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2924 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2925 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2926 | again: |
| 2927 | this_parent = root; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2928 | spin_lock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2929 | repeat: |
| 2930 | next = this_parent->d_subdirs.next; |
| 2931 | resume: |
| 2932 | while (next != &this_parent->d_subdirs) { |
| 2933 | struct list_head *tmp = next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2934 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2935 | next = tmp->next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2936 | |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 2937 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
| 2938 | if (d_unhashed(dentry) || !dentry->d_inode) { |
| 2939 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2940 | continue; |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 2941 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2942 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2943 | spin_unlock(&this_parent->d_lock); |
| 2944 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2945 | this_parent = dentry; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2946 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2947 | goto repeat; |
| 2948 | } |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2949 | if (!(dentry->d_flags & DCACHE_GENOCIDE)) { |
| 2950 | dentry->d_flags |= DCACHE_GENOCIDE; |
| 2951 | dentry->d_count--; |
| 2952 | } |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 2953 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2954 | } |
| 2955 | if (this_parent != root) { |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 2956 | struct dentry *child = this_parent; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2957 | if (!(this_parent->d_flags & DCACHE_GENOCIDE)) { |
| 2958 | this_parent->d_flags |= DCACHE_GENOCIDE; |
| 2959 | this_parent->d_count--; |
| 2960 | } |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 2961 | this_parent = try_to_ascend(this_parent, locked, seq); |
| 2962 | if (!this_parent) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2963 | goto rename_retry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2964 | next = child->d_u.d_child.next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2965 | goto resume; |
| 2966 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2967 | spin_unlock(&this_parent->d_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2968 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2969 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2970 | if (locked) |
| 2971 | write_sequnlock(&rename_lock); |
| 2972 | return; |
| 2973 | |
| 2974 | rename_retry: |
Miklos Szeredi | 8110e16 | 2012-09-17 22:23:30 +0200 | [diff] [blame] | 2975 | if (locked) |
| 2976 | goto again; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2977 | locked = 1; |
| 2978 | write_seqlock(&rename_lock); |
| 2979 | goto again; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2980 | } |
| 2981 | |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 2982 | void d_tmpfile(struct dentry *dentry, struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2983 | { |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 2984 | inode_dec_link_count(inode); |
| 2985 | BUG_ON(dentry->d_name.name != dentry->d_iname || |
| 2986 | !hlist_unhashed(&dentry->d_alias) || |
| 2987 | !d_unlinked(dentry)); |
| 2988 | spin_lock(&dentry->d_parent->d_lock); |
| 2989 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
| 2990 | dentry->d_name.len = sprintf(dentry->d_iname, "#%llu", |
| 2991 | (unsigned long long)inode->i_ino); |
| 2992 | spin_unlock(&dentry->d_lock); |
| 2993 | spin_unlock(&dentry->d_parent->d_lock); |
| 2994 | d_instantiate(dentry, inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2995 | } |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 2996 | EXPORT_SYMBOL(d_tmpfile); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2997 | |
| 2998 | static __initdata unsigned long dhash_entries; |
| 2999 | static int __init set_dhash_entries(char *str) |
| 3000 | { |
| 3001 | if (!str) |
| 3002 | return 0; |
| 3003 | dhash_entries = simple_strtoul(str, &str, 0); |
| 3004 | return 1; |
| 3005 | } |
| 3006 | __setup("dhash_entries=", set_dhash_entries); |
| 3007 | |
| 3008 | static void __init dcache_init_early(void) |
| 3009 | { |
Dimitri Sivanich | 074b851 | 2012-02-08 12:39:07 -0800 | [diff] [blame] | 3010 | unsigned int loop; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3011 | |
| 3012 | /* If hashes are distributed across NUMA nodes, defer |
| 3013 | * hash allocation until vmalloc space is available. |
| 3014 | */ |
| 3015 | if (hashdist) |
| 3016 | return; |
| 3017 | |
| 3018 | dentry_hashtable = |
| 3019 | alloc_large_system_hash("Dentry cache", |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 3020 | sizeof(struct hlist_bl_head), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3021 | dhash_entries, |
| 3022 | 13, |
| 3023 | HASH_EARLY, |
| 3024 | &d_hash_shift, |
| 3025 | &d_hash_mask, |
Tim Bird | 31fe62b | 2012-05-23 13:33:35 +0000 | [diff] [blame] | 3026 | 0, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3027 | 0); |
| 3028 | |
Dimitri Sivanich | 074b851 | 2012-02-08 12:39:07 -0800 | [diff] [blame] | 3029 | for (loop = 0; loop < (1U << d_hash_shift); loop++) |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 3030 | INIT_HLIST_BL_HEAD(dentry_hashtable + loop); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3031 | } |
| 3032 | |
Denis Cheng | 74bf17c | 2007-10-16 23:26:30 -0700 | [diff] [blame] | 3033 | static void __init dcache_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3034 | { |
Dimitri Sivanich | 074b851 | 2012-02-08 12:39:07 -0800 | [diff] [blame] | 3035 | unsigned int loop; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3036 | |
| 3037 | /* |
| 3038 | * A constructor could be added for stable state like the lists, |
| 3039 | * but it is probably not worth it because of the cache nature |
| 3040 | * of the dcache. |
| 3041 | */ |
Christoph Lameter | 0a31bd5 | 2007-05-06 14:49:57 -0700 | [diff] [blame] | 3042 | dentry_cache = KMEM_CACHE(dentry, |
| 3043 | SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3044 | |
| 3045 | /* Hash may have been set up in dcache_init_early */ |
| 3046 | if (!hashdist) |
| 3047 | return; |
| 3048 | |
| 3049 | dentry_hashtable = |
| 3050 | alloc_large_system_hash("Dentry cache", |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 3051 | sizeof(struct hlist_bl_head), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3052 | dhash_entries, |
| 3053 | 13, |
| 3054 | 0, |
| 3055 | &d_hash_shift, |
| 3056 | &d_hash_mask, |
Tim Bird | 31fe62b | 2012-05-23 13:33:35 +0000 | [diff] [blame] | 3057 | 0, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3058 | 0); |
| 3059 | |
Dimitri Sivanich | 074b851 | 2012-02-08 12:39:07 -0800 | [diff] [blame] | 3060 | for (loop = 0; loop < (1U << d_hash_shift); loop++) |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 3061 | INIT_HLIST_BL_HEAD(dentry_hashtable + loop); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3062 | } |
| 3063 | |
| 3064 | /* SLAB cache for __getname() consumers */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 3065 | struct kmem_cache *names_cachep __read_mostly; |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 3066 | EXPORT_SYMBOL(names_cachep); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3067 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3068 | EXPORT_SYMBOL(d_genocide); |
| 3069 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3070 | void __init vfs_caches_init_early(void) |
| 3071 | { |
| 3072 | dcache_init_early(); |
| 3073 | inode_init_early(); |
| 3074 | } |
| 3075 | |
| 3076 | void __init vfs_caches_init(unsigned long mempages) |
| 3077 | { |
| 3078 | unsigned long reserve; |
| 3079 | |
| 3080 | /* Base hash sizes on available memory, with a reserve equal to |
| 3081 | 150% of current kernel size */ |
| 3082 | |
| 3083 | reserve = min((mempages - nr_free_pages()) * 3/2, mempages - 1); |
| 3084 | mempages -= reserve; |
| 3085 | |
| 3086 | names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0, |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 3087 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3088 | |
Denis Cheng | 74bf17c | 2007-10-16 23:26:30 -0700 | [diff] [blame] | 3089 | dcache_init(); |
| 3090 | inode_init(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3091 | files_init(mempages); |
Denis Cheng | 74bf17c | 2007-10-16 23:26:30 -0700 | [diff] [blame] | 3092 | mnt_init(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3093 | bdev_cache_init(); |
| 3094 | chrdev_init(); |
| 3095 | } |