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> |
| 26 | #include <linux/module.h> |
| 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 | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 107 | static inline struct hlist_bl_head *d_hash(struct dentry *parent, |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 108 | unsigned long hash) |
| 109 | { |
| 110 | hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES; |
| 111 | hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS); |
| 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 | |
Christoph Hellwig | 9c82ab9 | 2010-10-10 05:36:22 -0400 | [diff] [blame] | 140 | static void __d_free(struct rcu_head *head) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | { |
Christoph Hellwig | 9c82ab9 | 2010-10-10 05:36:22 -0400 | [diff] [blame] | 142 | struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); |
| 143 | |
Arjan van de Ven | fd217f4 | 2008-10-21 06:47:33 -0700 | [diff] [blame] | 144 | WARN_ON(!list_empty(&dentry->d_alias)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 145 | if (dname_external(dentry)) |
| 146 | kfree(dentry->d_name.name); |
| 147 | kmem_cache_free(dentry_cache, dentry); |
| 148 | } |
| 149 | |
| 150 | /* |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 151 | * no locks, please. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | */ |
| 153 | static void d_free(struct dentry *dentry) |
| 154 | { |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 155 | BUG_ON(dentry->d_count); |
Nick Piggin | 3e880fb | 2011-01-07 17:49:19 +1100 | [diff] [blame] | 156 | this_cpu_dec(nr_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | if (dentry->d_op && dentry->d_op->d_release) |
| 158 | dentry->d_op->d_release(dentry); |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 159 | |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 160 | /* if dentry was never visible to RCU, immediate free is OK */ |
| 161 | if (!(dentry->d_flags & DCACHE_RCUACCESS)) |
Christoph Hellwig | 9c82ab9 | 2010-10-10 05:36:22 -0400 | [diff] [blame] | 162 | __d_free(&dentry->d_u.d_rcu); |
Eric Dumazet | b342341 | 2006-12-06 20:38:48 -0800 | [diff] [blame] | 163 | else |
Christoph Hellwig | 9c82ab9 | 2010-10-10 05:36:22 -0400 | [diff] [blame] | 164 | call_rcu(&dentry->d_u.d_rcu, __d_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | } |
| 166 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 167 | /** |
| 168 | * dentry_rcuwalk_barrier - invalidate in-progress rcu-walk lookups |
Randy Dunlap | ff5fdb6 | 2011-01-22 20:16:06 -0800 | [diff] [blame] | 169 | * @dentry: the target dentry |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 170 | * After this call, in-progress rcu-walk path lookup will fail. This |
| 171 | * should be called after unhashing, and after changing d_inode (if |
| 172 | * the dentry has not already been unhashed). |
| 173 | */ |
| 174 | static inline void dentry_rcuwalk_barrier(struct dentry *dentry) |
| 175 | { |
| 176 | assert_spin_locked(&dentry->d_lock); |
| 177 | /* Go through a barrier */ |
| 178 | write_seqcount_barrier(&dentry->d_seq); |
| 179 | } |
| 180 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | /* |
| 182 | * Release the dentry's inode, using the filesystem |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 183 | * d_iput() operation if defined. Dentry has no refcount |
| 184 | * and is unhashed. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 186 | static void dentry_iput(struct dentry * dentry) |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 187 | __releases(dentry->d_lock) |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 188 | __releases(dentry->d_inode->i_lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | { |
| 190 | struct inode *inode = dentry->d_inode; |
| 191 | if (inode) { |
| 192 | dentry->d_inode = NULL; |
| 193 | list_del_init(&dentry->d_alias); |
| 194 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 195 | spin_unlock(&inode->i_lock); |
Linus Torvalds | f805fbd | 2005-09-19 19:54:29 -0700 | [diff] [blame] | 196 | if (!inode->i_nlink) |
| 197 | fsnotify_inoderemove(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 198 | if (dentry->d_op && dentry->d_op->d_iput) |
| 199 | dentry->d_op->d_iput(dentry, inode); |
| 200 | else |
| 201 | iput(inode); |
| 202 | } else { |
| 203 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | } |
| 205 | } |
| 206 | |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 207 | /* |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 208 | * Release the dentry's inode, using the filesystem |
| 209 | * d_iput() operation if defined. dentry remains in-use. |
| 210 | */ |
| 211 | static void dentry_unlink_inode(struct dentry * dentry) |
| 212 | __releases(dentry->d_lock) |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 213 | __releases(dentry->d_inode->i_lock) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 214 | { |
| 215 | struct inode *inode = dentry->d_inode; |
| 216 | dentry->d_inode = NULL; |
| 217 | list_del_init(&dentry->d_alias); |
| 218 | dentry_rcuwalk_barrier(dentry); |
| 219 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 220 | spin_unlock(&inode->i_lock); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 221 | if (!inode->i_nlink) |
| 222 | fsnotify_inoderemove(inode); |
| 223 | if (dentry->d_op && dentry->d_op->d_iput) |
| 224 | dentry->d_op->d_iput(dentry, inode); |
| 225 | else |
| 226 | iput(inode); |
| 227 | } |
| 228 | |
| 229 | /* |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 230 | * 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] | 231 | */ |
| 232 | static void dentry_lru_add(struct dentry *dentry) |
| 233 | { |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 234 | if (list_empty(&dentry->d_lru)) { |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 235 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 236 | list_add(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); |
| 237 | dentry->d_sb->s_nr_dentry_unused++; |
Nick Piggin | 86c8749 | 2011-01-07 17:49:18 +1100 | [diff] [blame] | 238 | dentry_stat.nr_unused++; |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 239 | spin_unlock(&dcache_lru_lock); |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 240 | } |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 241 | } |
| 242 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 243 | static void __dentry_lru_del(struct dentry *dentry) |
| 244 | { |
| 245 | list_del_init(&dentry->d_lru); |
| 246 | dentry->d_sb->s_nr_dentry_unused--; |
| 247 | dentry_stat.nr_unused--; |
| 248 | } |
| 249 | |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 250 | /* |
| 251 | * Remove a dentry with references from the LRU. |
| 252 | */ |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 253 | static void dentry_lru_del(struct dentry *dentry) |
| 254 | { |
| 255 | if (!list_empty(&dentry->d_lru)) { |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 256 | spin_lock(&dcache_lru_lock); |
| 257 | __dentry_lru_del(dentry); |
| 258 | spin_unlock(&dcache_lru_lock); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 259 | } |
| 260 | } |
| 261 | |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 262 | /* |
| 263 | * Remove a dentry that is unreferenced and about to be pruned |
| 264 | * (unhashed and destroyed) from the LRU, and inform the file system. |
| 265 | * This wrapper should be called _prior_ to unhashing a victim dentry. |
| 266 | */ |
| 267 | static void dentry_lru_prune(struct dentry *dentry) |
| 268 | { |
| 269 | if (!list_empty(&dentry->d_lru)) { |
| 270 | if (dentry->d_flags & DCACHE_OP_PRUNE) |
| 271 | dentry->d_op->d_prune(dentry); |
| 272 | |
| 273 | spin_lock(&dcache_lru_lock); |
| 274 | __dentry_lru_del(dentry); |
| 275 | spin_unlock(&dcache_lru_lock); |
| 276 | } |
| 277 | } |
| 278 | |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 279 | static void dentry_lru_move_tail(struct dentry *dentry) |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 280 | { |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 281 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 282 | if (list_empty(&dentry->d_lru)) { |
| 283 | list_add_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); |
| 284 | dentry->d_sb->s_nr_dentry_unused++; |
Nick Piggin | 86c8749 | 2011-01-07 17:49:18 +1100 | [diff] [blame] | 285 | dentry_stat.nr_unused++; |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 286 | } else { |
| 287 | list_move_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 288 | } |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 289 | spin_unlock(&dcache_lru_lock); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 290 | } |
| 291 | |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 292 | /** |
| 293 | * d_kill - kill dentry and return parent |
| 294 | * @dentry: dentry to kill |
Randy Dunlap | ff5fdb6 | 2011-01-22 20:16:06 -0800 | [diff] [blame] | 295 | * @parent: parent dentry |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 296 | * |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 297 | * The dentry must already be unhashed and removed from the LRU. |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 298 | * |
| 299 | * If this is the root of the dentry tree, return NULL. |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 300 | * |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 301 | * dentry->d_lock and parent->d_lock must be held by caller, and are dropped by |
| 302 | * d_kill. |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 303 | */ |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 304 | static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent) |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 305 | __releases(dentry->d_lock) |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 306 | __releases(parent->d_lock) |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 307 | __releases(dentry->d_inode->i_lock) |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 308 | { |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 309 | list_del(&dentry->d_u.d_child); |
Trond Myklebust | c83ce98 | 2011-03-15 13:36:43 -0400 | [diff] [blame] | 310 | /* |
| 311 | * Inform try_to_ascend() that we are no longer attached to the |
| 312 | * dentry tree |
| 313 | */ |
| 314 | dentry->d_flags |= DCACHE_DISCONNECTED; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 315 | if (parent) |
| 316 | spin_unlock(&parent->d_lock); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 317 | dentry_iput(dentry); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 318 | /* |
| 319 | * dentry_iput drops the locks, at which point nobody (except |
| 320 | * transient RCU lookups) can reach this dentry. |
| 321 | */ |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 322 | d_free(dentry); |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 323 | return parent; |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 324 | } |
| 325 | |
David Howells | c6627c6 | 2011-06-07 14:09:20 +0100 | [diff] [blame] | 326 | /* |
| 327 | * Unhash a dentry without inserting an RCU walk barrier or checking that |
| 328 | * dentry->d_lock is locked. The caller must take care of that, if |
| 329 | * appropriate. |
| 330 | */ |
| 331 | static void __d_shrink(struct dentry *dentry) |
| 332 | { |
| 333 | if (!d_unhashed(dentry)) { |
| 334 | struct hlist_bl_head *b; |
| 335 | if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) |
| 336 | b = &dentry->d_sb->s_anon; |
| 337 | else |
| 338 | b = d_hash(dentry->d_parent, dentry->d_name.hash); |
| 339 | |
| 340 | hlist_bl_lock(b); |
| 341 | __hlist_bl_del(&dentry->d_hash); |
| 342 | dentry->d_hash.pprev = NULL; |
| 343 | hlist_bl_unlock(b); |
| 344 | } |
| 345 | } |
| 346 | |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 347 | /** |
| 348 | * d_drop - drop a dentry |
| 349 | * @dentry: dentry to drop |
| 350 | * |
| 351 | * d_drop() unhashes the entry from the parent dentry hashes, so that it won't |
| 352 | * be found through a VFS lookup any more. Note that this is different from |
| 353 | * deleting the dentry - d_delete will try to mark the dentry negative if |
| 354 | * possible, giving a successful _negative_ lookup, while d_drop will |
| 355 | * just make the cache lookup fail. |
| 356 | * |
| 357 | * d_drop() is used mainly for stuff that wants to invalidate a dentry for some |
| 358 | * reason (NFS timeouts or autofs deletes). |
| 359 | * |
| 360 | * __d_drop requires dentry->d_lock. |
| 361 | */ |
| 362 | void __d_drop(struct dentry *dentry) |
| 363 | { |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 364 | if (!d_unhashed(dentry)) { |
David Howells | c6627c6 | 2011-06-07 14:09:20 +0100 | [diff] [blame] | 365 | __d_shrink(dentry); |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 366 | dentry_rcuwalk_barrier(dentry); |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 367 | } |
| 368 | } |
| 369 | EXPORT_SYMBOL(__d_drop); |
| 370 | |
| 371 | void d_drop(struct dentry *dentry) |
| 372 | { |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 373 | spin_lock(&dentry->d_lock); |
| 374 | __d_drop(dentry); |
| 375 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 376 | } |
| 377 | EXPORT_SYMBOL(d_drop); |
| 378 | |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 379 | /* |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 380 | * d_clear_need_lookup - drop a dentry from cache and clear the need lookup flag |
| 381 | * @dentry: dentry to drop |
| 382 | * |
| 383 | * This is called when we do a lookup on a placeholder dentry that needed to be |
| 384 | * looked up. The dentry should have been hashed in order for it to be found by |
| 385 | * the lookup code, but now needs to be unhashed while we do the actual lookup |
| 386 | * and clear the DCACHE_NEED_LOOKUP flag. |
| 387 | */ |
| 388 | void d_clear_need_lookup(struct dentry *dentry) |
| 389 | { |
| 390 | spin_lock(&dentry->d_lock); |
| 391 | __d_drop(dentry); |
| 392 | dentry->d_flags &= ~DCACHE_NEED_LOOKUP; |
| 393 | spin_unlock(&dentry->d_lock); |
| 394 | } |
| 395 | EXPORT_SYMBOL(d_clear_need_lookup); |
| 396 | |
| 397 | /* |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 398 | * Finish off a dentry we've decided to kill. |
| 399 | * dentry->d_lock must be held, returns with it unlocked. |
| 400 | * If ref is non-zero, then decrement the refcount too. |
| 401 | * Returns dentry requiring refcount drop, or NULL if we're done. |
| 402 | */ |
| 403 | static inline struct dentry *dentry_kill(struct dentry *dentry, int ref) |
| 404 | __releases(dentry->d_lock) |
| 405 | { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 406 | struct inode *inode; |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 407 | struct dentry *parent; |
| 408 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 409 | inode = dentry->d_inode; |
| 410 | if (inode && !spin_trylock(&inode->i_lock)) { |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 411 | relock: |
| 412 | spin_unlock(&dentry->d_lock); |
| 413 | cpu_relax(); |
| 414 | return dentry; /* try again with same dentry */ |
| 415 | } |
| 416 | if (IS_ROOT(dentry)) |
| 417 | parent = NULL; |
| 418 | else |
| 419 | parent = dentry->d_parent; |
| 420 | if (parent && !spin_trylock(&parent->d_lock)) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 421 | if (inode) |
| 422 | spin_unlock(&inode->i_lock); |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 423 | goto relock; |
| 424 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 425 | |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 426 | if (ref) |
| 427 | dentry->d_count--; |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 428 | /* |
| 429 | * if dentry was on the d_lru list delete it from there. |
| 430 | * inform the fs via d_prune that this dentry is about to be |
| 431 | * unhashed and destroyed. |
| 432 | */ |
| 433 | dentry_lru_prune(dentry); |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 434 | /* if it was on the hash then remove it */ |
| 435 | __d_drop(dentry); |
| 436 | return d_kill(dentry, parent); |
| 437 | } |
| 438 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 439 | /* |
| 440 | * This is dput |
| 441 | * |
| 442 | * This is complicated by the fact that we do not want to put |
| 443 | * dentries that are no longer on any hash chain on the unused |
| 444 | * list: we'd much rather just get rid of them immediately. |
| 445 | * |
| 446 | * However, that implies that we have to traverse the dentry |
| 447 | * tree upwards to the parents which might _also_ now be |
| 448 | * scheduled for deletion (it may have been only waiting for |
| 449 | * its last child to go away). |
| 450 | * |
| 451 | * This tail recursion is done by hand as we don't want to depend |
| 452 | * on the compiler to always get this right (gcc generally doesn't). |
| 453 | * Real recursion would eat up our stack space. |
| 454 | */ |
| 455 | |
| 456 | /* |
| 457 | * dput - release a dentry |
| 458 | * @dentry: dentry to release |
| 459 | * |
| 460 | * Release a dentry. This will drop the usage count and if appropriate |
| 461 | * call the dentry unlink method as well as removing it from the queues and |
| 462 | * releasing its resources. If the parent dentries were scheduled for release |
| 463 | * they too may now get deleted. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 465 | void dput(struct dentry *dentry) |
| 466 | { |
| 467 | if (!dentry) |
| 468 | return; |
| 469 | |
| 470 | repeat: |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 471 | if (dentry->d_count == 1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | might_sleep(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 473 | spin_lock(&dentry->d_lock); |
Nick Piggin | 61f3dee | 2011-01-07 17:49:40 +1100 | [diff] [blame] | 474 | BUG_ON(!dentry->d_count); |
| 475 | if (dentry->d_count > 1) { |
| 476 | dentry->d_count--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 478 | return; |
| 479 | } |
| 480 | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 481 | if (dentry->d_flags & DCACHE_OP_DELETE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 482 | if (dentry->d_op->d_delete(dentry)) |
Nick Piggin | 61f3dee | 2011-01-07 17:49:40 +1100 | [diff] [blame] | 483 | goto kill_it; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 484 | } |
Nick Piggin | 265ac90 | 2010-10-10 05:36:24 -0400 | [diff] [blame] | 485 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 486 | /* Unreachable? Get rid of it */ |
| 487 | if (d_unhashed(dentry)) |
| 488 | goto kill_it; |
Nick Piggin | 265ac90 | 2010-10-10 05:36:24 -0400 | [diff] [blame] | 489 | |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 490 | /* |
| 491 | * If this dentry needs lookup, don't set the referenced flag so that it |
| 492 | * is more likely to be cleaned up by the dcache shrinker in case of |
| 493 | * memory pressure. |
| 494 | */ |
| 495 | if (!d_need_lookup(dentry)) |
| 496 | dentry->d_flags |= DCACHE_REFERENCED; |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 497 | dentry_lru_add(dentry); |
Nick Piggin | 265ac90 | 2010-10-10 05:36:24 -0400 | [diff] [blame] | 498 | |
Nick Piggin | 61f3dee | 2011-01-07 17:49:40 +1100 | [diff] [blame] | 499 | dentry->d_count--; |
| 500 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 501 | return; |
| 502 | |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 503 | kill_it: |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 504 | dentry = dentry_kill(dentry, 1); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 505 | if (dentry) |
| 506 | goto repeat; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 508 | EXPORT_SYMBOL(dput); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | |
| 510 | /** |
| 511 | * d_invalidate - invalidate a dentry |
| 512 | * @dentry: dentry to invalidate |
| 513 | * |
| 514 | * Try to invalidate the dentry if it turns out to be |
| 515 | * possible. If there are other dentries that can be |
| 516 | * reached through this one we can't delete it and we |
| 517 | * return -EBUSY. On success we return 0. |
| 518 | * |
| 519 | * no dcache lock. |
| 520 | */ |
| 521 | |
| 522 | int d_invalidate(struct dentry * dentry) |
| 523 | { |
| 524 | /* |
| 525 | * If it's already been dropped, return OK. |
| 526 | */ |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 527 | spin_lock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 528 | if (d_unhashed(dentry)) { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 529 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | return 0; |
| 531 | } |
| 532 | /* |
| 533 | * Check whether to do a partial shrink_dcache |
| 534 | * to get rid of unused child entries. |
| 535 | */ |
| 536 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 537 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 538 | shrink_dcache_parent(dentry); |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 539 | spin_lock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | } |
| 541 | |
| 542 | /* |
| 543 | * Somebody else still using it? |
| 544 | * |
| 545 | * If it's a directory, we can't drop it |
| 546 | * for fear of somebody re-populating it |
| 547 | * with children (even though dropping it |
| 548 | * would make it unreachable from the root, |
| 549 | * we might still populate it if it was a |
| 550 | * working directory or similar). |
Al Viro | 50e6963 | 2011-11-07 16:39:57 +0000 | [diff] [blame] | 551 | * We also need to leave mountpoints alone, |
| 552 | * directory or not. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | */ |
Al Viro | 50e6963 | 2011-11-07 16:39:57 +0000 | [diff] [blame] | 554 | if (dentry->d_count > 1 && dentry->d_inode) { |
| 555 | if (S_ISDIR(dentry->d_inode->i_mode) || d_mountpoint(dentry)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 556 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 557 | return -EBUSY; |
| 558 | } |
| 559 | } |
| 560 | |
| 561 | __d_drop(dentry); |
| 562 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | return 0; |
| 564 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 565 | EXPORT_SYMBOL(d_invalidate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 567 | /* This must be called with d_lock held */ |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 568 | static inline void __dget_dlock(struct dentry *dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 569 | { |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 570 | dentry->d_count++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 571 | } |
| 572 | |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 573 | static inline void __dget(struct dentry *dentry) |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 574 | { |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 575 | spin_lock(&dentry->d_lock); |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 576 | __dget_dlock(dentry); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 577 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 578 | } |
| 579 | |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 580 | struct dentry *dget_parent(struct dentry *dentry) |
| 581 | { |
| 582 | struct dentry *ret; |
| 583 | |
| 584 | repeat: |
Nick Piggin | a734eb4 | 2011-01-07 17:49:44 +1100 | [diff] [blame] | 585 | /* |
| 586 | * Don't need rcu_dereference because we re-check it was correct under |
| 587 | * the lock. |
| 588 | */ |
| 589 | rcu_read_lock(); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 590 | ret = dentry->d_parent; |
Nick Piggin | a734eb4 | 2011-01-07 17:49:44 +1100 | [diff] [blame] | 591 | spin_lock(&ret->d_lock); |
| 592 | if (unlikely(ret != dentry->d_parent)) { |
| 593 | spin_unlock(&ret->d_lock); |
| 594 | rcu_read_unlock(); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 595 | goto repeat; |
| 596 | } |
Nick Piggin | a734eb4 | 2011-01-07 17:49:44 +1100 | [diff] [blame] | 597 | rcu_read_unlock(); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 598 | BUG_ON(!ret->d_count); |
| 599 | ret->d_count++; |
| 600 | spin_unlock(&ret->d_lock); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 601 | return ret; |
| 602 | } |
| 603 | EXPORT_SYMBOL(dget_parent); |
| 604 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | /** |
| 606 | * d_find_alias - grab a hashed alias of inode |
| 607 | * @inode: inode in question |
| 608 | * @want_discon: flag, used by d_splice_alias, to request |
| 609 | * that only a DISCONNECTED alias be returned. |
| 610 | * |
| 611 | * If inode has a hashed alias, or is a directory and has any alias, |
| 612 | * acquire the reference to alias and return it. Otherwise return NULL. |
| 613 | * Notice that if inode is a directory there can be only one alias and |
| 614 | * it can be unhashed only if it has no children, or if it is the root |
| 615 | * of a filesystem. |
| 616 | * |
NeilBrown | 21c0d8f | 2006-10-04 02:16:16 -0700 | [diff] [blame] | 617 | * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 618 | * any other hashed alias over that one unless @want_discon is set, |
NeilBrown | 21c0d8f | 2006-10-04 02:16:16 -0700 | [diff] [blame] | 619 | * in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | */ |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 621 | static struct dentry *__d_find_alias(struct inode *inode, int want_discon) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 622 | { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 623 | struct dentry *alias, *discon_alias; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 624 | |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 625 | again: |
| 626 | discon_alias = NULL; |
| 627 | list_for_each_entry(alias, &inode->i_dentry, d_alias) { |
| 628 | spin_lock(&alias->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 629 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { |
NeilBrown | 21c0d8f | 2006-10-04 02:16:16 -0700 | [diff] [blame] | 630 | if (IS_ROOT(alias) && |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 631 | (alias->d_flags & DCACHE_DISCONNECTED)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 | discon_alias = alias; |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 633 | } else if (!want_discon) { |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 634 | __dget_dlock(alias); |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 635 | spin_unlock(&alias->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 636 | return alias; |
| 637 | } |
| 638 | } |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 639 | spin_unlock(&alias->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | } |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 641 | if (discon_alias) { |
| 642 | alias = discon_alias; |
| 643 | spin_lock(&alias->d_lock); |
| 644 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { |
| 645 | if (IS_ROOT(alias) && |
| 646 | (alias->d_flags & DCACHE_DISCONNECTED)) { |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 647 | __dget_dlock(alias); |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 648 | spin_unlock(&alias->d_lock); |
| 649 | return alias; |
| 650 | } |
| 651 | } |
| 652 | spin_unlock(&alias->d_lock); |
| 653 | goto again; |
| 654 | } |
| 655 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | } |
| 657 | |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 658 | struct dentry *d_find_alias(struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | { |
David Howells | 214fda1 | 2006-03-25 03:06:36 -0800 | [diff] [blame] | 660 | struct dentry *de = NULL; |
| 661 | |
| 662 | if (!list_empty(&inode->i_dentry)) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 663 | spin_lock(&inode->i_lock); |
David Howells | 214fda1 | 2006-03-25 03:06:36 -0800 | [diff] [blame] | 664 | de = __d_find_alias(inode, 0); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 665 | spin_unlock(&inode->i_lock); |
David Howells | 214fda1 | 2006-03-25 03:06:36 -0800 | [diff] [blame] | 666 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 667 | return de; |
| 668 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 669 | EXPORT_SYMBOL(d_find_alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 670 | |
| 671 | /* |
| 672 | * Try to kill dentries associated with this inode. |
| 673 | * WARNING: you must own a reference to inode. |
| 674 | */ |
| 675 | void d_prune_aliases(struct inode *inode) |
| 676 | { |
Domen Puncer | 0cdca3f | 2005-09-10 00:27:07 -0700 | [diff] [blame] | 677 | struct dentry *dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | restart: |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 679 | spin_lock(&inode->i_lock); |
Domen Puncer | 0cdca3f | 2005-09-10 00:27:07 -0700 | [diff] [blame] | 680 | list_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | spin_lock(&dentry->d_lock); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 682 | if (!dentry->d_count) { |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 683 | __dget_dlock(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | __d_drop(dentry); |
| 685 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 686 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 687 | dput(dentry); |
| 688 | goto restart; |
| 689 | } |
| 690 | spin_unlock(&dentry->d_lock); |
| 691 | } |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 692 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 693 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 694 | EXPORT_SYMBOL(d_prune_aliases); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 695 | |
| 696 | /* |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 697 | * Try to throw away a dentry - free the inode, dput the parent. |
| 698 | * Requires dentry->d_lock is held, and dentry->d_count == 0. |
| 699 | * Releases dentry->d_lock. |
Andrew Morton | d702ccb | 2006-06-22 14:47:31 -0700 | [diff] [blame] | 700 | * |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 701 | * 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] | 702 | */ |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 703 | static void try_prune_one_dentry(struct dentry *dentry) |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 704 | __releases(dentry->d_lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 705 | { |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 706 | struct dentry *parent; |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 707 | |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 708 | parent = dentry_kill(dentry, 0); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 709 | /* |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 710 | * If dentry_kill returns NULL, we have nothing more to do. |
| 711 | * if it returns the same dentry, trylocks failed. In either |
| 712 | * case, just loop again. |
| 713 | * |
| 714 | * Otherwise, we need to prune ancestors too. This is necessary |
| 715 | * to prevent quadratic behavior of shrink_dcache_parent(), but |
| 716 | * is also expected to be beneficial in reducing dentry cache |
| 717 | * fragmentation. |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 718 | */ |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 719 | if (!parent) |
| 720 | return; |
| 721 | if (parent == dentry) |
| 722 | return; |
| 723 | |
| 724 | /* Prune ancestors. */ |
| 725 | dentry = parent; |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 726 | while (dentry) { |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 727 | spin_lock(&dentry->d_lock); |
Nick Piggin | 89e6054 | 2011-01-07 17:49:45 +1100 | [diff] [blame] | 728 | if (dentry->d_count > 1) { |
| 729 | dentry->d_count--; |
| 730 | spin_unlock(&dentry->d_lock); |
| 731 | return; |
| 732 | } |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 733 | dentry = dentry_kill(dentry, 1); |
Miklos Szeredi | d52b908 | 2007-05-08 00:23:46 -0700 | [diff] [blame] | 734 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 735 | } |
| 736 | |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 737 | static void shrink_dentry_list(struct list_head *list) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 738 | { |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 739 | struct dentry *dentry; |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 740 | |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 741 | rcu_read_lock(); |
| 742 | for (;;) { |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 743 | dentry = list_entry_rcu(list->prev, struct dentry, d_lru); |
| 744 | if (&dentry->d_lru == list) |
| 745 | break; /* empty */ |
| 746 | spin_lock(&dentry->d_lock); |
| 747 | if (dentry != list_entry(list->prev, struct dentry, d_lru)) { |
| 748 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 749 | continue; |
| 750 | } |
| 751 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 752 | /* |
| 753 | * We found an inuse dentry which was not removed from |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 754 | * the LRU because of laziness during lookup. Do not free |
| 755 | * it - just keep it off the LRU list. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 756 | */ |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 757 | if (dentry->d_count) { |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 758 | dentry_lru_del(dentry); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 759 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 760 | continue; |
| 761 | } |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 762 | |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 763 | rcu_read_unlock(); |
Nick Piggin | 77812a1 | 2011-01-07 17:49:48 +1100 | [diff] [blame] | 764 | |
| 765 | try_prune_one_dentry(dentry); |
| 766 | |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 767 | rcu_read_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | } |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 769 | rcu_read_unlock(); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 770 | } |
| 771 | |
| 772 | /** |
| 773 | * __shrink_dcache_sb - shrink the dentry LRU on a given superblock |
| 774 | * @sb: superblock to shrink dentry LRU. |
| 775 | * @count: number of entries to prune |
| 776 | * @flags: flags to control the dentry processing |
| 777 | * |
| 778 | * If flags contains DCACHE_REFERENCED reference dentries will not be pruned. |
| 779 | */ |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 780 | static void __shrink_dcache_sb(struct super_block *sb, int count, int flags) |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 781 | { |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 782 | struct dentry *dentry; |
| 783 | LIST_HEAD(referenced); |
| 784 | LIST_HEAD(tmp); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 785 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 786 | relock: |
| 787 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 788 | while (!list_empty(&sb->s_dentry_lru)) { |
| 789 | dentry = list_entry(sb->s_dentry_lru.prev, |
| 790 | struct dentry, d_lru); |
| 791 | BUG_ON(dentry->d_sb != sb); |
| 792 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 793 | if (!spin_trylock(&dentry->d_lock)) { |
| 794 | spin_unlock(&dcache_lru_lock); |
| 795 | cpu_relax(); |
| 796 | goto relock; |
| 797 | } |
| 798 | |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 799 | /* |
| 800 | * If we are honouring the DCACHE_REFERENCED flag and the |
| 801 | * dentry has this flag set, don't free it. Clear the flag |
| 802 | * and put it back on the LRU. |
| 803 | */ |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 804 | if (flags & DCACHE_REFERENCED && |
| 805 | dentry->d_flags & DCACHE_REFERENCED) { |
| 806 | dentry->d_flags &= ~DCACHE_REFERENCED; |
| 807 | list_move(&dentry->d_lru, &referenced); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 808 | spin_unlock(&dentry->d_lock); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 809 | } else { |
| 810 | list_move_tail(&dentry->d_lru, &tmp); |
| 811 | spin_unlock(&dentry->d_lock); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 812 | if (!--count) |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 813 | break; |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 814 | } |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 815 | cond_resched_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 816 | } |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 817 | if (!list_empty(&referenced)) |
| 818 | list_splice(&referenced, &sb->s_dentry_lru); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 819 | spin_unlock(&dcache_lru_lock); |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 820 | |
| 821 | shrink_dentry_list(&tmp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 822 | } |
| 823 | |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 824 | /** |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 825 | * prune_dcache_sb - shrink the dcache |
Randy Dunlap | 2af1416 | 2011-08-03 16:21:07 -0700 | [diff] [blame] | 826 | * @sb: superblock |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 827 | * @nr_to_scan: number of entries to try to free |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 828 | * |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 829 | * Attempt to shrink the superblock dcache LRU by @nr_to_scan entries. This is |
| 830 | * done when we need more memory an called from the superblock shrinker |
| 831 | * function. |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 832 | * |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 833 | * This function may fail to free any resources if all the dentries are in |
| 834 | * use. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 835 | */ |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 836 | void prune_dcache_sb(struct super_block *sb, int nr_to_scan) |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 837 | { |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 838 | __shrink_dcache_sb(sb, nr_to_scan, DCACHE_REFERENCED); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 839 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 840 | |
| 841 | /** |
| 842 | * shrink_dcache_sb - shrink dcache for a superblock |
| 843 | * @sb: superblock |
| 844 | * |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 845 | * Shrink the dcache for the specified super block. This is used to free |
| 846 | * the dcache before unmounting a file system. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 847 | */ |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 848 | void shrink_dcache_sb(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 849 | { |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 850 | LIST_HEAD(tmp); |
| 851 | |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 852 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 853 | while (!list_empty(&sb->s_dentry_lru)) { |
| 854 | list_splice_init(&sb->s_dentry_lru, &tmp); |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 855 | spin_unlock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 856 | shrink_dentry_list(&tmp); |
Nick Piggin | ec33679 | 2011-01-07 17:49:47 +1100 | [diff] [blame] | 857 | spin_lock(&dcache_lru_lock); |
Christoph Hellwig | 3049cfe | 2010-10-10 05:36:25 -0400 | [diff] [blame] | 858 | } |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 859 | spin_unlock(&dcache_lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 860 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 861 | EXPORT_SYMBOL(shrink_dcache_sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 862 | |
| 863 | /* |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 864 | * destroy a single subtree of dentries for unmount |
| 865 | * - see the comments on shrink_dcache_for_umount() for a description of the |
| 866 | * locking |
| 867 | */ |
| 868 | static void shrink_dcache_for_umount_subtree(struct dentry *dentry) |
| 869 | { |
| 870 | struct dentry *parent; |
| 871 | |
| 872 | BUG_ON(!IS_ROOT(dentry)); |
| 873 | |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 874 | for (;;) { |
| 875 | /* descend to the first leaf in the current subtree */ |
David Howells | 43c1c9c | 2011-06-07 14:09:30 +0100 | [diff] [blame] | 876 | while (!list_empty(&dentry->d_subdirs)) |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 877 | dentry = list_entry(dentry->d_subdirs.next, |
| 878 | struct dentry, d_u.d_child); |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 879 | |
| 880 | /* consume the dentries from this leaf up through its parents |
| 881 | * until we find one with children or run out altogether */ |
| 882 | do { |
| 883 | struct inode *inode; |
| 884 | |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 885 | /* |
| 886 | * remove the dentry from the lru, and inform |
| 887 | * the fs that this dentry is about to be |
| 888 | * unhashed and destroyed. |
| 889 | */ |
| 890 | dentry_lru_prune(dentry); |
David Howells | 43c1c9c | 2011-06-07 14:09:30 +0100 | [diff] [blame] | 891 | __d_shrink(dentry); |
| 892 | |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 893 | if (dentry->d_count != 0) { |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 894 | printk(KERN_ERR |
| 895 | "BUG: Dentry %p{i=%lx,n=%s}" |
| 896 | " still in use (%d)" |
| 897 | " [unmount of %s %s]\n", |
| 898 | dentry, |
| 899 | dentry->d_inode ? |
| 900 | dentry->d_inode->i_ino : 0UL, |
| 901 | dentry->d_name.name, |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 902 | dentry->d_count, |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 903 | dentry->d_sb->s_type->name, |
| 904 | dentry->d_sb->s_id); |
| 905 | BUG(); |
| 906 | } |
| 907 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 908 | if (IS_ROOT(dentry)) { |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 909 | parent = NULL; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 910 | list_del(&dentry->d_u.d_child); |
| 911 | } else { |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 912 | parent = dentry->d_parent; |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 913 | parent->d_count--; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 914 | list_del(&dentry->d_u.d_child); |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 915 | } |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 916 | |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 917 | inode = dentry->d_inode; |
| 918 | if (inode) { |
| 919 | dentry->d_inode = NULL; |
| 920 | list_del_init(&dentry->d_alias); |
| 921 | if (dentry->d_op && dentry->d_op->d_iput) |
| 922 | dentry->d_op->d_iput(dentry, inode); |
| 923 | else |
| 924 | iput(inode); |
| 925 | } |
| 926 | |
| 927 | d_free(dentry); |
| 928 | |
| 929 | /* finished when we fall off the top of the tree, |
| 930 | * otherwise we ascend to the parent and move to the |
| 931 | * next sibling if there is one */ |
| 932 | if (!parent) |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 933 | return; |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 934 | dentry = parent; |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 935 | } while (list_empty(&dentry->d_subdirs)); |
| 936 | |
| 937 | dentry = list_entry(dentry->d_subdirs.next, |
| 938 | struct dentry, d_u.d_child); |
| 939 | } |
| 940 | } |
| 941 | |
| 942 | /* |
| 943 | * destroy the dentries attached to a superblock on unmounting |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 944 | * - we don't need to use dentry->d_lock because: |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 945 | * - the superblock is detached from all mountings and open files, so the |
| 946 | * dentry trees will not be rearranged by the VFS |
| 947 | * - s_umount is write-locked, so the memory pressure shrinker will ignore |
| 948 | * any dentries belonging to this superblock that it comes across |
| 949 | * - the filesystem itself is no longer permitted to rearrange the dentries |
| 950 | * in this superblock |
| 951 | */ |
| 952 | void shrink_dcache_for_umount(struct super_block *sb) |
| 953 | { |
| 954 | struct dentry *dentry; |
| 955 | |
| 956 | if (down_read_trylock(&sb->s_umount)) |
| 957 | BUG(); |
| 958 | |
| 959 | dentry = sb->s_root; |
| 960 | sb->s_root = NULL; |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 961 | dentry->d_count--; |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 962 | shrink_dcache_for_umount_subtree(dentry); |
| 963 | |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 964 | while (!hlist_bl_empty(&sb->s_anon)) { |
| 965 | 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] | 966 | shrink_dcache_for_umount_subtree(dentry); |
| 967 | } |
| 968 | } |
| 969 | |
| 970 | /* |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 971 | * This tries to ascend one level of parenthood, but |
| 972 | * we can race with renaming, so we need to re-check |
| 973 | * the parenthood after dropping the lock and check |
| 974 | * that the sequence number still matches. |
| 975 | */ |
| 976 | static struct dentry *try_to_ascend(struct dentry *old, int locked, unsigned seq) |
| 977 | { |
| 978 | struct dentry *new = old->d_parent; |
| 979 | |
| 980 | rcu_read_lock(); |
| 981 | spin_unlock(&old->d_lock); |
| 982 | spin_lock(&new->d_lock); |
| 983 | |
| 984 | /* |
| 985 | * might go back up the wrong parent if we have had a rename |
| 986 | * or deletion |
| 987 | */ |
| 988 | if (new != old->d_parent || |
Trond Myklebust | c83ce98 | 2011-03-15 13:36:43 -0400 | [diff] [blame] | 989 | (old->d_flags & DCACHE_DISCONNECTED) || |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 990 | (!locked && read_seqretry(&rename_lock, seq))) { |
| 991 | spin_unlock(&new->d_lock); |
| 992 | new = NULL; |
| 993 | } |
| 994 | rcu_read_unlock(); |
| 995 | return new; |
| 996 | } |
| 997 | |
| 998 | |
| 999 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1000 | * Search for at least 1 mount point in the dentry's subdirs. |
| 1001 | * We descend to the next level whenever the d_subdirs |
| 1002 | * list is non-empty and continue searching. |
| 1003 | */ |
| 1004 | |
| 1005 | /** |
| 1006 | * have_submounts - check for mounts over a dentry |
| 1007 | * @parent: dentry to check. |
| 1008 | * |
| 1009 | * Return true if the parent or its subdirectories contain |
| 1010 | * a mount point |
| 1011 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1012 | int have_submounts(struct dentry *parent) |
| 1013 | { |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1014 | struct dentry *this_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1015 | struct list_head *next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1016 | unsigned seq; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1017 | int locked = 0; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1018 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1019 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1020 | again: |
| 1021 | this_parent = parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1022 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1023 | if (d_mountpoint(parent)) |
| 1024 | goto positive; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1025 | spin_lock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1026 | repeat: |
| 1027 | next = this_parent->d_subdirs.next; |
| 1028 | resume: |
| 1029 | while (next != &this_parent->d_subdirs) { |
| 1030 | struct list_head *tmp = next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 1031 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1032 | next = tmp->next; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1033 | |
| 1034 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1035 | /* Have we found a mount point ? */ |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1036 | if (d_mountpoint(dentry)) { |
| 1037 | spin_unlock(&dentry->d_lock); |
| 1038 | spin_unlock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1039 | goto positive; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1040 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1041 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1042 | spin_unlock(&this_parent->d_lock); |
| 1043 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1044 | this_parent = dentry; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1045 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1046 | goto repeat; |
| 1047 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1048 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1049 | } |
| 1050 | /* |
| 1051 | * All done at this level ... ascend and resume the search. |
| 1052 | */ |
| 1053 | if (this_parent != parent) { |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 1054 | struct dentry *child = this_parent; |
| 1055 | this_parent = try_to_ascend(this_parent, locked, seq); |
| 1056 | if (!this_parent) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1057 | goto rename_retry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1058 | next = child->d_u.d_child.next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1059 | goto resume; |
| 1060 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1061 | spin_unlock(&this_parent->d_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1062 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1063 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1064 | if (locked) |
| 1065 | write_sequnlock(&rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1066 | return 0; /* No mount points found in tree */ |
| 1067 | positive: |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1068 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1069 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1070 | if (locked) |
| 1071 | write_sequnlock(&rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1072 | return 1; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1073 | |
| 1074 | rename_retry: |
| 1075 | locked = 1; |
| 1076 | write_seqlock(&rename_lock); |
| 1077 | goto again; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1078 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1079 | EXPORT_SYMBOL(have_submounts); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1080 | |
| 1081 | /* |
| 1082 | * Search the dentry child list for the specified parent, |
| 1083 | * and move any unused dentries to the end of the unused |
| 1084 | * list for prune_dcache(). We descend to the next level |
| 1085 | * whenever the d_subdirs list is non-empty and continue |
| 1086 | * searching. |
| 1087 | * |
| 1088 | * It returns zero iff there are no unused children, |
| 1089 | * otherwise it returns the number of children moved to |
| 1090 | * the end of the unused list. This may not be the total |
| 1091 | * number of unused children, because select_parent can |
| 1092 | * drop the lock and return early due to latency |
| 1093 | * constraints. |
| 1094 | */ |
| 1095 | static int select_parent(struct dentry * parent) |
| 1096 | { |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1097 | struct dentry *this_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1098 | struct list_head *next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1099 | unsigned seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1100 | int found = 0; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1101 | int locked = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1102 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1103 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1104 | again: |
| 1105 | this_parent = parent; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1106 | spin_lock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1107 | repeat: |
| 1108 | next = this_parent->d_subdirs.next; |
| 1109 | resume: |
| 1110 | while (next != &this_parent->d_subdirs) { |
| 1111 | struct list_head *tmp = next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 1112 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1113 | next = tmp->next; |
| 1114 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1115 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
Nick Piggin | 2304450 | 2011-01-07 17:49:31 +1100 | [diff] [blame] | 1116 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1117 | /* |
| 1118 | * move only zero ref count dentries to the end |
| 1119 | * of the unused list for prune_dcache |
| 1120 | */ |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 1121 | if (!dentry->d_count) { |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 1122 | dentry_lru_move_tail(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1123 | found++; |
Christoph Hellwig | a463335 | 2010-10-10 05:36:26 -0400 | [diff] [blame] | 1124 | } else { |
| 1125 | dentry_lru_del(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1126 | } |
| 1127 | |
| 1128 | /* |
| 1129 | * We can return to the caller if we have found some (this |
| 1130 | * ensures forward progress). We'll be coming back to find |
| 1131 | * the rest. |
| 1132 | */ |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1133 | if (found && need_resched()) { |
| 1134 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1135 | goto out; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1136 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1137 | |
| 1138 | /* |
| 1139 | * Descend a level if the d_subdirs list is non-empty. |
| 1140 | */ |
| 1141 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1142 | spin_unlock(&this_parent->d_lock); |
| 1143 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1144 | this_parent = dentry; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1145 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1146 | goto repeat; |
| 1147 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1148 | |
| 1149 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1150 | } |
| 1151 | /* |
| 1152 | * All done at this level ... ascend and resume the search. |
| 1153 | */ |
| 1154 | if (this_parent != parent) { |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 1155 | struct dentry *child = this_parent; |
| 1156 | this_parent = try_to_ascend(this_parent, locked, seq); |
| 1157 | if (!this_parent) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1158 | goto rename_retry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1159 | next = child->d_u.d_child.next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1160 | goto resume; |
| 1161 | } |
| 1162 | out: |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1163 | spin_unlock(&this_parent->d_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1164 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1165 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1166 | if (locked) |
| 1167 | write_sequnlock(&rename_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1168 | return found; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 1169 | |
| 1170 | rename_retry: |
| 1171 | if (found) |
| 1172 | return found; |
| 1173 | locked = 1; |
| 1174 | write_seqlock(&rename_lock); |
| 1175 | goto again; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1176 | } |
| 1177 | |
| 1178 | /** |
| 1179 | * shrink_dcache_parent - prune dcache |
| 1180 | * @parent: parent of entries to prune |
| 1181 | * |
| 1182 | * Prune the dcache to remove unused children of the parent dentry. |
| 1183 | */ |
| 1184 | |
| 1185 | void shrink_dcache_parent(struct dentry * parent) |
| 1186 | { |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 1187 | struct super_block *sb = parent->d_sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1188 | int found; |
| 1189 | |
| 1190 | while ((found = select_parent(parent)) != 0) |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 1191 | __shrink_dcache_sb(sb, found, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1192 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1193 | EXPORT_SYMBOL(shrink_dcache_parent); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1194 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1195 | /** |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1196 | * __d_alloc - allocate a dcache entry |
| 1197 | * @sb: filesystem it will belong to |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1198 | * @name: qstr of the name |
| 1199 | * |
| 1200 | * Allocates a dentry. It returns %NULL if there is insufficient memory |
| 1201 | * available. On a success the dentry is returned. The name passed in is |
| 1202 | * copied and the copy passed in may be reused after this call. |
| 1203 | */ |
| 1204 | |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1205 | struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1206 | { |
| 1207 | struct dentry *dentry; |
| 1208 | char *dname; |
| 1209 | |
Mel Gorman | e12ba74 | 2007-10-16 01:25:52 -0700 | [diff] [blame] | 1210 | dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1211 | if (!dentry) |
| 1212 | return NULL; |
| 1213 | |
| 1214 | if (name->len > DNAME_INLINE_LEN-1) { |
| 1215 | dname = kmalloc(name->len + 1, GFP_KERNEL); |
| 1216 | if (!dname) { |
| 1217 | kmem_cache_free(dentry_cache, dentry); |
| 1218 | return NULL; |
| 1219 | } |
| 1220 | } else { |
| 1221 | dname = dentry->d_iname; |
| 1222 | } |
| 1223 | dentry->d_name.name = dname; |
| 1224 | |
| 1225 | dentry->d_name.len = name->len; |
| 1226 | dentry->d_name.hash = name->hash; |
| 1227 | memcpy(dname, name->name, name->len); |
| 1228 | dname[name->len] = 0; |
| 1229 | |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 1230 | dentry->d_count = 1; |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 1231 | dentry->d_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1232 | spin_lock_init(&dentry->d_lock); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1233 | seqcount_init(&dentry->d_seq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1234 | dentry->d_inode = NULL; |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1235 | dentry->d_parent = dentry; |
| 1236 | dentry->d_sb = sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1237 | dentry->d_op = NULL; |
| 1238 | dentry->d_fsdata = NULL; |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1239 | INIT_HLIST_BL_NODE(&dentry->d_hash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1240 | INIT_LIST_HEAD(&dentry->d_lru); |
| 1241 | INIT_LIST_HEAD(&dentry->d_subdirs); |
| 1242 | INIT_LIST_HEAD(&dentry->d_alias); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1243 | INIT_LIST_HEAD(&dentry->d_u.d_child); |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1244 | d_set_d_op(dentry, dentry->d_sb->s_d_op); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1245 | |
Nick Piggin | 3e880fb | 2011-01-07 17:49:19 +1100 | [diff] [blame] | 1246 | this_cpu_inc(nr_dentry); |
Christoph Hellwig | 312d3ca | 2010-10-10 05:36:23 -0400 | [diff] [blame] | 1247 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1248 | return dentry; |
| 1249 | } |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1250 | |
| 1251 | /** |
| 1252 | * d_alloc - allocate a dcache entry |
| 1253 | * @parent: parent of entry to allocate |
| 1254 | * @name: qstr of the name |
| 1255 | * |
| 1256 | * Allocates a dentry. It returns %NULL if there is insufficient memory |
| 1257 | * available. On a success the dentry is returned. The name passed in is |
| 1258 | * copied and the copy passed in may be reused after this call. |
| 1259 | */ |
| 1260 | struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) |
| 1261 | { |
| 1262 | struct dentry *dentry = __d_alloc(parent->d_sb, name); |
| 1263 | if (!dentry) |
| 1264 | return NULL; |
| 1265 | |
| 1266 | spin_lock(&parent->d_lock); |
| 1267 | /* |
| 1268 | * don't need child lock because it is not subject |
| 1269 | * to concurrency here |
| 1270 | */ |
| 1271 | __dget_dlock(parent); |
| 1272 | dentry->d_parent = parent; |
| 1273 | list_add(&dentry->d_u.d_child, &parent->d_subdirs); |
| 1274 | spin_unlock(&parent->d_lock); |
| 1275 | |
| 1276 | return dentry; |
| 1277 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1278 | EXPORT_SYMBOL(d_alloc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1279 | |
Nick Piggin | 4b93688 | 2011-01-07 17:50:07 +1100 | [diff] [blame] | 1280 | struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name) |
| 1281 | { |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1282 | struct dentry *dentry = __d_alloc(sb, name); |
| 1283 | if (dentry) |
Nick Piggin | 4b93688 | 2011-01-07 17:50:07 +1100 | [diff] [blame] | 1284 | dentry->d_flags |= DCACHE_DISCONNECTED; |
Nick Piggin | 4b93688 | 2011-01-07 17:50:07 +1100 | [diff] [blame] | 1285 | return dentry; |
| 1286 | } |
| 1287 | EXPORT_SYMBOL(d_alloc_pseudo); |
| 1288 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1289 | struct dentry *d_alloc_name(struct dentry *parent, const char *name) |
| 1290 | { |
| 1291 | struct qstr q; |
| 1292 | |
| 1293 | q.name = name; |
| 1294 | q.len = strlen(name); |
| 1295 | q.hash = full_name_hash(q.name, q.len); |
| 1296 | return d_alloc(parent, &q); |
| 1297 | } |
H Hartley Sweeten | ef26ca9 | 2009-09-29 20:09:42 -0400 | [diff] [blame] | 1298 | EXPORT_SYMBOL(d_alloc_name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1299 | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1300 | void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) |
| 1301 | { |
Linus Torvalds | 6f7f7ca | 2011-01-14 13:26:18 -0800 | [diff] [blame] | 1302 | WARN_ON_ONCE(dentry->d_op); |
| 1303 | WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH | |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1304 | DCACHE_OP_COMPARE | |
| 1305 | DCACHE_OP_REVALIDATE | |
| 1306 | DCACHE_OP_DELETE )); |
| 1307 | dentry->d_op = op; |
| 1308 | if (!op) |
| 1309 | return; |
| 1310 | if (op->d_hash) |
| 1311 | dentry->d_flags |= DCACHE_OP_HASH; |
| 1312 | if (op->d_compare) |
| 1313 | dentry->d_flags |= DCACHE_OP_COMPARE; |
| 1314 | if (op->d_revalidate) |
| 1315 | dentry->d_flags |= DCACHE_OP_REVALIDATE; |
| 1316 | if (op->d_delete) |
| 1317 | dentry->d_flags |= DCACHE_OP_DELETE; |
Sage Weil | f0023bc | 2011-10-28 10:02:42 -0700 | [diff] [blame] | 1318 | if (op->d_prune) |
| 1319 | dentry->d_flags |= DCACHE_OP_PRUNE; |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1320 | |
| 1321 | } |
| 1322 | EXPORT_SYMBOL(d_set_d_op); |
| 1323 | |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1324 | static void __d_instantiate(struct dentry *dentry, struct inode *inode) |
| 1325 | { |
Nick Piggin | b23fb0a | 2011-01-07 17:49:35 +1100 | [diff] [blame] | 1326 | spin_lock(&dentry->d_lock); |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1327 | if (inode) { |
| 1328 | if (unlikely(IS_AUTOMOUNT(inode))) |
| 1329 | dentry->d_flags |= DCACHE_NEED_AUTOMOUNT; |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1330 | list_add(&dentry->d_alias, &inode->i_dentry); |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1331 | } |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1332 | dentry->d_inode = inode; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1333 | dentry_rcuwalk_barrier(dentry); |
Nick Piggin | b23fb0a | 2011-01-07 17:49:35 +1100 | [diff] [blame] | 1334 | spin_unlock(&dentry->d_lock); |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1335 | fsnotify_d_instantiate(dentry, inode); |
| 1336 | } |
| 1337 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1338 | /** |
| 1339 | * d_instantiate - fill in inode information for a dentry |
| 1340 | * @entry: dentry to complete |
| 1341 | * @inode: inode to attach to this dentry |
| 1342 | * |
| 1343 | * Fill in inode information in the entry. |
| 1344 | * |
| 1345 | * This turns negative dentries into productive full members |
| 1346 | * of society. |
| 1347 | * |
| 1348 | * NOTE! This assumes that the inode count has been incremented |
| 1349 | * (or otherwise set) by the caller to indicate that it is now |
| 1350 | * in use by the dcache. |
| 1351 | */ |
| 1352 | |
| 1353 | void d_instantiate(struct dentry *entry, struct inode * inode) |
| 1354 | { |
Eric Sesterhenn | 28133c7 | 2006-03-26 18:25:39 +0200 | [diff] [blame] | 1355 | BUG_ON(!list_empty(&entry->d_alias)); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1356 | if (inode) |
| 1357 | spin_lock(&inode->i_lock); |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1358 | __d_instantiate(entry, inode); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1359 | if (inode) |
| 1360 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1361 | security_d_instantiate(entry, inode); |
| 1362 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1363 | EXPORT_SYMBOL(d_instantiate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1364 | |
| 1365 | /** |
| 1366 | * d_instantiate_unique - instantiate a non-aliased dentry |
| 1367 | * @entry: dentry to instantiate |
| 1368 | * @inode: inode to attach to this dentry |
| 1369 | * |
| 1370 | * Fill in inode information in the entry. On success, it returns NULL. |
| 1371 | * If an unhashed alias of "entry" already exists, then we return the |
Oleg Drokin | e866cfa | 2006-01-09 20:52:51 -0800 | [diff] [blame] | 1372 | * aliased dentry instead and drop one reference to inode. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1373 | * |
| 1374 | * Note that in order to avoid conflicts with rename() etc, the caller |
| 1375 | * had better be holding the parent directory semaphore. |
Oleg Drokin | e866cfa | 2006-01-09 20:52:51 -0800 | [diff] [blame] | 1376 | * |
| 1377 | * This also assumes that the inode count has been incremented |
| 1378 | * (or otherwise set) by the caller to indicate that it is now |
| 1379 | * in use by the dcache. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1380 | */ |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1381 | static struct dentry *__d_instantiate_unique(struct dentry *entry, |
| 1382 | struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1383 | { |
| 1384 | struct dentry *alias; |
| 1385 | int len = entry->d_name.len; |
| 1386 | const char *name = entry->d_name.name; |
| 1387 | unsigned int hash = entry->d_name.hash; |
| 1388 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1389 | if (!inode) { |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1390 | __d_instantiate(entry, NULL); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1391 | return NULL; |
| 1392 | } |
| 1393 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1394 | list_for_each_entry(alias, &inode->i_dentry, d_alias) { |
| 1395 | struct qstr *qstr = &alias->d_name; |
| 1396 | |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 1397 | /* |
| 1398 | * Don't need alias->d_lock here, because aliases with |
| 1399 | * d_parent == entry->d_parent are not subject to name or |
| 1400 | * parent changes, because the parent inode i_mutex is held. |
| 1401 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1402 | if (qstr->hash != hash) |
| 1403 | continue; |
| 1404 | if (alias->d_parent != entry->d_parent) |
| 1405 | continue; |
Nick Piggin | 9d55c36 | 2011-01-07 17:50:09 +1100 | [diff] [blame] | 1406 | if (dentry_cmp(qstr->name, qstr->len, name, len)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1407 | continue; |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 1408 | __dget(alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1409 | return alias; |
| 1410 | } |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1411 | |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1412 | __d_instantiate(entry, inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1413 | return NULL; |
| 1414 | } |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1415 | |
| 1416 | struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) |
| 1417 | { |
| 1418 | struct dentry *result; |
| 1419 | |
| 1420 | BUG_ON(!list_empty(&entry->d_alias)); |
| 1421 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1422 | if (inode) |
| 1423 | spin_lock(&inode->i_lock); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1424 | result = __d_instantiate_unique(entry, inode); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1425 | if (inode) |
| 1426 | spin_unlock(&inode->i_lock); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 1427 | |
| 1428 | if (!result) { |
| 1429 | security_d_instantiate(entry, inode); |
| 1430 | return NULL; |
| 1431 | } |
| 1432 | |
| 1433 | BUG_ON(!d_unhashed(result)); |
| 1434 | iput(inode); |
| 1435 | return result; |
| 1436 | } |
| 1437 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1438 | EXPORT_SYMBOL(d_instantiate_unique); |
| 1439 | |
| 1440 | /** |
| 1441 | * d_alloc_root - allocate root dentry |
| 1442 | * @root_inode: inode to allocate the root for |
| 1443 | * |
| 1444 | * Allocate a root ("/") dentry for the inode given. The inode is |
| 1445 | * instantiated and returned. %NULL is returned if there is insufficient |
| 1446 | * memory or the inode passed is %NULL. |
| 1447 | */ |
| 1448 | |
| 1449 | struct dentry * d_alloc_root(struct inode * root_inode) |
| 1450 | { |
| 1451 | struct dentry *res = NULL; |
| 1452 | |
| 1453 | if (root_inode) { |
| 1454 | static const struct qstr name = { .name = "/", .len = 1 }; |
| 1455 | |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1456 | res = __d_alloc(root_inode->i_sb, &name); |
| 1457 | if (res) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1458 | d_instantiate(res, root_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1459 | } |
| 1460 | return res; |
| 1461 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1462 | EXPORT_SYMBOL(d_alloc_root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1463 | |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1464 | static struct dentry * __d_find_any_alias(struct inode *inode) |
| 1465 | { |
| 1466 | struct dentry *alias; |
| 1467 | |
| 1468 | if (list_empty(&inode->i_dentry)) |
| 1469 | return NULL; |
| 1470 | alias = list_first_entry(&inode->i_dentry, struct dentry, d_alias); |
| 1471 | __dget(alias); |
| 1472 | return alias; |
| 1473 | } |
| 1474 | |
| 1475 | static struct dentry * d_find_any_alias(struct inode *inode) |
| 1476 | { |
| 1477 | struct dentry *de; |
| 1478 | |
| 1479 | spin_lock(&inode->i_lock); |
| 1480 | de = __d_find_any_alias(inode); |
| 1481 | spin_unlock(&inode->i_lock); |
| 1482 | return de; |
| 1483 | } |
| 1484 | |
| 1485 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1486 | /** |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1487 | * d_obtain_alias - find or allocate a dentry for a given inode |
| 1488 | * @inode: inode to allocate the dentry for |
| 1489 | * |
| 1490 | * Obtain a dentry for an inode resulting from NFS filehandle conversion or |
| 1491 | * similar open by handle operations. The returned dentry may be anonymous, |
| 1492 | * or may have a full name (if the inode was already in the cache). |
| 1493 | * |
| 1494 | * When called on a directory inode, we must ensure that the inode only ever |
| 1495 | * has one dentry. If a dentry is found, that is returned instead of |
| 1496 | * allocating a new one. |
| 1497 | * |
| 1498 | * On successful return, the reference to the inode has been transferred |
Christoph Hellwig | 4400372 | 2008-08-11 15:49:04 +0200 | [diff] [blame] | 1499 | * to the dentry. In case of an error the reference on the inode is released. |
| 1500 | * To make it easier to use in export operations a %NULL or IS_ERR inode may |
| 1501 | * be passed in and will be the error will be propagate to the return value, |
| 1502 | * with a %NULL @inode replaced by ERR_PTR(-ESTALE). |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1503 | */ |
| 1504 | struct dentry *d_obtain_alias(struct inode *inode) |
| 1505 | { |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1506 | static const struct qstr anonstring = { .name = "" }; |
| 1507 | struct dentry *tmp; |
| 1508 | struct dentry *res; |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1509 | |
| 1510 | if (!inode) |
Christoph Hellwig | 4400372 | 2008-08-11 15:49:04 +0200 | [diff] [blame] | 1511 | return ERR_PTR(-ESTALE); |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1512 | if (IS_ERR(inode)) |
| 1513 | return ERR_CAST(inode); |
| 1514 | |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1515 | res = d_find_any_alias(inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1516 | if (res) |
| 1517 | goto out_iput; |
| 1518 | |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 1519 | tmp = __d_alloc(inode->i_sb, &anonstring); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1520 | if (!tmp) { |
| 1521 | res = ERR_PTR(-ENOMEM); |
| 1522 | goto out_iput; |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1523 | } |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 1524 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1525 | spin_lock(&inode->i_lock); |
J. Bruce Fields | d891eed | 2011-01-18 15:45:09 -0500 | [diff] [blame] | 1526 | res = __d_find_any_alias(inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1527 | if (res) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1528 | spin_unlock(&inode->i_lock); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1529 | dput(tmp); |
| 1530 | goto out_iput; |
| 1531 | } |
| 1532 | |
| 1533 | /* attach a disconnected dentry */ |
| 1534 | spin_lock(&tmp->d_lock); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1535 | tmp->d_inode = inode; |
| 1536 | tmp->d_flags |= DCACHE_DISCONNECTED; |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1537 | list_add(&tmp->d_alias, &inode->i_dentry); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 1538 | hlist_bl_lock(&tmp->d_sb->s_anon); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1539 | hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 1540 | hlist_bl_unlock(&tmp->d_sb->s_anon); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1541 | spin_unlock(&tmp->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1542 | spin_unlock(&inode->i_lock); |
Josef Bacik | 24ff666 | 2010-11-18 20:52:55 -0500 | [diff] [blame] | 1543 | security_d_instantiate(tmp, inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1544 | |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1545 | return tmp; |
| 1546 | |
| 1547 | out_iput: |
Josef Bacik | 24ff666 | 2010-11-18 20:52:55 -0500 | [diff] [blame] | 1548 | if (res && !IS_ERR(res)) |
| 1549 | security_d_instantiate(res, inode); |
Christoph Hellwig | 9308a61 | 2008-08-11 15:49:12 +0200 | [diff] [blame] | 1550 | iput(inode); |
| 1551 | return res; |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1552 | } |
Benny Halevy | adc4872 | 2009-02-27 14:02:59 -0800 | [diff] [blame] | 1553 | EXPORT_SYMBOL(d_obtain_alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1554 | |
| 1555 | /** |
| 1556 | * d_splice_alias - splice a disconnected dentry into the tree if one exists |
| 1557 | * @inode: the inode which may have a disconnected dentry |
| 1558 | * @dentry: a negative dentry which we want to point to the inode. |
| 1559 | * |
| 1560 | * If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and |
| 1561 | * DCACHE_DISCONNECTED), then d_move that in place of the given dentry |
| 1562 | * and return it, else simply d_add the inode to the dentry and return NULL. |
| 1563 | * |
| 1564 | * This is needed in the lookup routine of any filesystem that is exportable |
| 1565 | * (via knfsd) so that we can build dcache paths to directories effectively. |
| 1566 | * |
| 1567 | * If a dentry was found and moved, then it is returned. Otherwise NULL |
| 1568 | * is returned. This matches the expected return value of ->lookup. |
| 1569 | * |
| 1570 | */ |
| 1571 | struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) |
| 1572 | { |
| 1573 | struct dentry *new = NULL; |
| 1574 | |
Al Viro | a904937 | 2011-07-08 21:20:11 -0400 | [diff] [blame] | 1575 | if (IS_ERR(inode)) |
| 1576 | return ERR_CAST(inode); |
| 1577 | |
NeilBrown | 21c0d8f | 2006-10-04 02:16:16 -0700 | [diff] [blame] | 1578 | if (inode && S_ISDIR(inode->i_mode)) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1579 | spin_lock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1580 | new = __d_find_alias(inode, 1); |
| 1581 | if (new) { |
| 1582 | BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED)); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1583 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1584 | security_d_instantiate(new, inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1585 | d_move(new, dentry); |
| 1586 | iput(inode); |
| 1587 | } else { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1588 | /* already taking inode->i_lock, so d_add() by hand */ |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1589 | __d_instantiate(dentry, inode); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1590 | spin_unlock(&inode->i_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1591 | security_d_instantiate(dentry, inode); |
| 1592 | d_rehash(dentry); |
| 1593 | } |
| 1594 | } else |
| 1595 | d_add(dentry, inode); |
| 1596 | return new; |
| 1597 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1598 | EXPORT_SYMBOL(d_splice_alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1599 | |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1600 | /** |
| 1601 | * d_add_ci - lookup or allocate new dentry with case-exact name |
| 1602 | * @inode: the inode case-insensitive lookup has found |
| 1603 | * @dentry: the negative dentry that was passed to the parent's lookup func |
| 1604 | * @name: the case-exact name to be associated with the returned dentry |
| 1605 | * |
| 1606 | * This is to avoid filling the dcache with case-insensitive names to the |
| 1607 | * same inode, only the actual correct case is stored in the dcache for |
| 1608 | * case-insensitive filesystems. |
| 1609 | * |
| 1610 | * For a case-insensitive lookup match and if the the case-exact dentry |
| 1611 | * already exists in in the dcache, use it and return it. |
| 1612 | * |
| 1613 | * If no entry exists with the exact case name, allocate new dentry with |
| 1614 | * the exact case, and return the spliced entry. |
| 1615 | */ |
Christoph Hellwig | e45b590 | 2008-08-07 23:49:07 +0200 | [diff] [blame] | 1616 | struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1617 | struct qstr *name) |
| 1618 | { |
| 1619 | int error; |
| 1620 | struct dentry *found; |
| 1621 | struct dentry *new; |
| 1622 | |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1623 | /* |
| 1624 | * First check if a dentry matching the name already exists, |
| 1625 | * if not go ahead and create it now. |
| 1626 | */ |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1627 | found = d_hash_and_lookup(dentry->d_parent, name); |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1628 | if (!found) { |
| 1629 | new = d_alloc(dentry->d_parent, name); |
| 1630 | if (!new) { |
| 1631 | error = -ENOMEM; |
| 1632 | goto err_out; |
| 1633 | } |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1634 | |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1635 | found = d_splice_alias(inode, new); |
| 1636 | if (found) { |
| 1637 | dput(new); |
| 1638 | return found; |
| 1639 | } |
| 1640 | return new; |
| 1641 | } |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1642 | |
| 1643 | /* |
| 1644 | * If a matching dentry exists, and it's not negative use it. |
| 1645 | * |
| 1646 | * Decrement the reference count to balance the iget() done |
| 1647 | * earlier on. |
| 1648 | */ |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1649 | if (found->d_inode) { |
| 1650 | if (unlikely(found->d_inode != inode)) { |
| 1651 | /* This can't happen because bad inodes are unhashed. */ |
| 1652 | BUG_ON(!is_bad_inode(inode)); |
| 1653 | BUG_ON(!is_bad_inode(found->d_inode)); |
| 1654 | } |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1655 | iput(inode); |
| 1656 | return found; |
| 1657 | } |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1658 | |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1659 | /* |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1660 | * We are going to instantiate this dentry, unhash it and clear the |
| 1661 | * lookup flag so we can do that. |
| 1662 | */ |
| 1663 | if (unlikely(d_need_lookup(found))) |
| 1664 | d_clear_need_lookup(found); |
| 1665 | |
| 1666 | /* |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1667 | * Negative dentry: instantiate it unless the inode is a directory and |
Christoph Hellwig | b6520c8 | 2009-01-05 19:10:37 +0100 | [diff] [blame] | 1668 | * already has a dentry. |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1669 | */ |
Al Viro | 4513d89 | 2011-07-17 10:52:14 -0400 | [diff] [blame] | 1670 | new = d_splice_alias(inode, found); |
| 1671 | if (new) { |
| 1672 | dput(found); |
| 1673 | found = new; |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1674 | } |
Al Viro | 4513d89 | 2011-07-17 10:52:14 -0400 | [diff] [blame] | 1675 | return found; |
Barry Naujok | 9403540 | 2008-05-21 16:50:46 +1000 | [diff] [blame] | 1676 | |
| 1677 | err_out: |
| 1678 | iput(inode); |
| 1679 | return ERR_PTR(error); |
| 1680 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1681 | EXPORT_SYMBOL(d_add_ci); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1682 | |
| 1683 | /** |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1684 | * __d_lookup_rcu - search for a dentry (racy, store-free) |
| 1685 | * @parent: parent dentry |
| 1686 | * @name: qstr of name we wish to find |
| 1687 | * @seq: returns d_seq value at the point where the dentry was found |
| 1688 | * @inode: returns dentry->d_inode when the inode was found valid. |
| 1689 | * Returns: dentry, or NULL |
| 1690 | * |
| 1691 | * __d_lookup_rcu is the dcache lookup function for rcu-walk name |
| 1692 | * resolution (store-free path walking) design described in |
| 1693 | * Documentation/filesystems/path-lookup.txt. |
| 1694 | * |
| 1695 | * This is not to be used outside core vfs. |
| 1696 | * |
| 1697 | * __d_lookup_rcu must only be used in rcu-walk mode, ie. with vfsmount lock |
| 1698 | * held, and rcu_read_lock held. The returned dentry must not be stored into |
| 1699 | * without taking d_lock and checking d_seq sequence count against @seq |
| 1700 | * returned here. |
| 1701 | * |
| 1702 | * A refcount may be taken on the found dentry with the __d_rcu_to_refcount |
| 1703 | * function. |
| 1704 | * |
| 1705 | * Alternatively, __d_lookup_rcu may be called again to look up the child of |
| 1706 | * the returned dentry, so long as its parent's seqlock is checked after the |
| 1707 | * child is looked up. Thus, an interlocking stepping of sequence lock checks |
| 1708 | * is formed, giving integrity down the path walk. |
| 1709 | */ |
| 1710 | struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, |
| 1711 | unsigned *seq, struct inode **inode) |
| 1712 | { |
| 1713 | unsigned int len = name->len; |
| 1714 | unsigned int hash = name->hash; |
| 1715 | const unsigned char *str = name->name; |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 1716 | struct hlist_bl_head *b = d_hash(parent, hash); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1717 | struct hlist_bl_node *node; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1718 | struct dentry *dentry; |
| 1719 | |
| 1720 | /* |
| 1721 | * Note: There is significant duplication with __d_lookup_rcu which is |
| 1722 | * required to prevent single threaded performance regressions |
| 1723 | * especially on architectures where smp_rmb (in seqcounts) are costly. |
| 1724 | * Keep the two functions in sync. |
| 1725 | */ |
| 1726 | |
| 1727 | /* |
| 1728 | * The hash list is protected using RCU. |
| 1729 | * |
| 1730 | * Carefully use d_seq when comparing a candidate dentry, to avoid |
| 1731 | * races with d_move(). |
| 1732 | * |
| 1733 | * It is possible that concurrent renames can mess up our list |
| 1734 | * walk here and result in missing our dentry, resulting in the |
| 1735 | * false-negative result. d_lookup() protects against concurrent |
| 1736 | * renames using rename_lock seqlock. |
| 1737 | * |
Namhyung Kim | b0a4bb8 | 2011-01-22 15:31:32 +0900 | [diff] [blame] | 1738 | * See Documentation/filesystems/path-lookup.txt for more details. |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1739 | */ |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 1740 | hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1741 | struct inode *i; |
| 1742 | const char *tname; |
| 1743 | int tlen; |
| 1744 | |
| 1745 | if (dentry->d_name.hash != hash) |
| 1746 | continue; |
| 1747 | |
| 1748 | seqretry: |
| 1749 | *seq = read_seqcount_begin(&dentry->d_seq); |
| 1750 | if (dentry->d_parent != parent) |
| 1751 | continue; |
| 1752 | if (d_unhashed(dentry)) |
| 1753 | continue; |
| 1754 | tlen = dentry->d_name.len; |
| 1755 | tname = dentry->d_name.name; |
| 1756 | i = dentry->d_inode; |
Nick Piggin | e1bb578 | 2011-01-07 17:50:08 +1100 | [diff] [blame] | 1757 | prefetch(tname); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1758 | /* |
| 1759 | * This seqcount check is required to ensure name and |
| 1760 | * len are loaded atomically, so as not to walk off the |
| 1761 | * edge of memory when walking. If we could load this |
| 1762 | * atomically some other way, we could drop this check. |
| 1763 | */ |
| 1764 | if (read_seqcount_retry(&dentry->d_seq, *seq)) |
| 1765 | goto seqretry; |
Linus Torvalds | 830c0f0 | 2011-08-06 22:41:50 -0700 | [diff] [blame] | 1766 | if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1767 | if (parent->d_op->d_compare(parent, *inode, |
| 1768 | dentry, i, |
| 1769 | tlen, tname, name)) |
| 1770 | continue; |
| 1771 | } else { |
Nick Piggin | 9d55c36 | 2011-01-07 17:50:09 +1100 | [diff] [blame] | 1772 | if (dentry_cmp(tname, tlen, str, len)) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1773 | continue; |
| 1774 | } |
| 1775 | /* |
| 1776 | * No extra seqcount check is required after the name |
| 1777 | * compare. The caller must perform a seqcount check in |
| 1778 | * order to do anything useful with the returned dentry |
| 1779 | * anyway. |
| 1780 | */ |
| 1781 | *inode = i; |
| 1782 | return dentry; |
| 1783 | } |
| 1784 | return NULL; |
| 1785 | } |
| 1786 | |
| 1787 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1788 | * d_lookup - search for a dentry |
| 1789 | * @parent: parent dentry |
| 1790 | * @name: qstr of name we wish to find |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1791 | * Returns: dentry, or NULL |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1792 | * |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1793 | * d_lookup searches the children of the parent dentry for the name in |
| 1794 | * question. If the dentry is found its reference count is incremented and the |
| 1795 | * dentry is returned. The caller must use dput to free the entry when it has |
| 1796 | * finished using it. %NULL is returned if the dentry does not exist. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1797 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1798 | struct dentry *d_lookup(struct dentry *parent, struct qstr *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1799 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1800 | struct dentry *dentry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 1801 | unsigned seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1802 | |
| 1803 | do { |
| 1804 | seq = read_seqbegin(&rename_lock); |
| 1805 | dentry = __d_lookup(parent, name); |
| 1806 | if (dentry) |
| 1807 | break; |
| 1808 | } while (read_seqretry(&rename_lock, seq)); |
| 1809 | return dentry; |
| 1810 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1811 | EXPORT_SYMBOL(d_lookup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1812 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1813 | /** |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1814 | * __d_lookup - search for a dentry (racy) |
| 1815 | * @parent: parent dentry |
| 1816 | * @name: qstr of name we wish to find |
| 1817 | * Returns: dentry, or NULL |
| 1818 | * |
| 1819 | * __d_lookup is like d_lookup, however it may (rarely) return a |
| 1820 | * false-negative result due to unrelated rename activity. |
| 1821 | * |
| 1822 | * __d_lookup is slightly faster by avoiding rename_lock read seqlock, |
| 1823 | * however it must be used carefully, eg. with a following d_lookup in |
| 1824 | * the case of failure. |
| 1825 | * |
| 1826 | * __d_lookup callers must be commented. |
| 1827 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1828 | struct dentry *__d_lookup(struct dentry *parent, struct qstr *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1829 | { |
| 1830 | unsigned int len = name->len; |
| 1831 | unsigned int hash = name->hash; |
| 1832 | const unsigned char *str = name->name; |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 1833 | struct hlist_bl_head *b = d_hash(parent, hash); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 1834 | struct hlist_bl_node *node; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1835 | struct dentry *found = NULL; |
Paul E. McKenney | 665a758 | 2005-11-07 00:59:17 -0800 | [diff] [blame] | 1836 | struct dentry *dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1837 | |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1838 | /* |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1839 | * Note: There is significant duplication with __d_lookup_rcu which is |
| 1840 | * required to prevent single threaded performance regressions |
| 1841 | * especially on architectures where smp_rmb (in seqcounts) are costly. |
| 1842 | * Keep the two functions in sync. |
| 1843 | */ |
| 1844 | |
| 1845 | /* |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1846 | * The hash list is protected using RCU. |
| 1847 | * |
| 1848 | * Take d_lock when comparing a candidate dentry, to avoid races |
| 1849 | * with d_move(). |
| 1850 | * |
| 1851 | * It is possible that concurrent renames can mess up our list |
| 1852 | * walk here and result in missing our dentry, resulting in the |
| 1853 | * false-negative result. d_lookup() protects against concurrent |
| 1854 | * renames using rename_lock seqlock. |
| 1855 | * |
Namhyung Kim | b0a4bb8 | 2011-01-22 15:31:32 +0900 | [diff] [blame] | 1856 | * See Documentation/filesystems/path-lookup.txt for more details. |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1857 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1858 | rcu_read_lock(); |
| 1859 | |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 1860 | hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1861 | const char *tname; |
| 1862 | int tlen; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1863 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1864 | if (dentry->d_name.hash != hash) |
| 1865 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1866 | |
| 1867 | spin_lock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1868 | if (dentry->d_parent != parent) |
| 1869 | goto next; |
Linus Torvalds | d0185c0 | 2008-09-29 07:42:57 -0700 | [diff] [blame] | 1870 | if (d_unhashed(dentry)) |
| 1871 | goto next; |
| 1872 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1873 | /* |
| 1874 | * It is safe to compare names since d_move() cannot |
| 1875 | * change the qstr (protected by d_lock). |
| 1876 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1877 | tlen = dentry->d_name.len; |
| 1878 | tname = dentry->d_name.name; |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1879 | if (parent->d_flags & DCACHE_OP_COMPARE) { |
Nick Piggin | 621e155 | 2011-01-07 17:49:27 +1100 | [diff] [blame] | 1880 | if (parent->d_op->d_compare(parent, parent->d_inode, |
| 1881 | dentry, dentry->d_inode, |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1882 | tlen, tname, name)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1883 | goto next; |
| 1884 | } else { |
Nick Piggin | 9d55c36 | 2011-01-07 17:50:09 +1100 | [diff] [blame] | 1885 | if (dentry_cmp(tname, tlen, str, len)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1886 | goto next; |
| 1887 | } |
| 1888 | |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 1889 | dentry->d_count++; |
Linus Torvalds | d0185c0 | 2008-09-29 07:42:57 -0700 | [diff] [blame] | 1890 | found = dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1891 | spin_unlock(&dentry->d_lock); |
| 1892 | break; |
| 1893 | next: |
| 1894 | spin_unlock(&dentry->d_lock); |
| 1895 | } |
| 1896 | rcu_read_unlock(); |
| 1897 | |
| 1898 | return found; |
| 1899 | } |
| 1900 | |
| 1901 | /** |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 1902 | * d_hash_and_lookup - hash the qstr then search for a dentry |
| 1903 | * @dir: Directory to search in |
| 1904 | * @name: qstr of name we wish to find |
| 1905 | * |
| 1906 | * On hash failure or on lookup failure NULL is returned. |
| 1907 | */ |
| 1908 | struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name) |
| 1909 | { |
| 1910 | struct dentry *dentry = NULL; |
| 1911 | |
| 1912 | /* |
| 1913 | * Check for a fs-specific hash function. Note that we must |
| 1914 | * calculate the standard hash first, as the d_op->d_hash() |
| 1915 | * routine may choose to leave the hash value unchanged. |
| 1916 | */ |
| 1917 | name->hash = full_name_hash(name->name, name->len); |
Nick Piggin | fb045ad | 2011-01-07 17:49:55 +1100 | [diff] [blame] | 1918 | if (dir->d_flags & DCACHE_OP_HASH) { |
Nick Piggin | b1e6a01 | 2011-01-07 17:49:28 +1100 | [diff] [blame] | 1919 | if (dir->d_op->d_hash(dir, dir->d_inode, name) < 0) |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 1920 | goto out; |
| 1921 | } |
| 1922 | dentry = d_lookup(dir, name); |
| 1923 | out: |
| 1924 | return dentry; |
| 1925 | } |
| 1926 | |
| 1927 | /** |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 1928 | * d_validate - verify dentry provided from insecure source (deprecated) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1929 | * @dentry: The dentry alleged to be valid child of @dparent |
Randy Dunlap | ff5fdb6 | 2011-01-22 20:16:06 -0800 | [diff] [blame] | 1930 | * @dparent: The parent dentry (known to be valid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1931 | * |
| 1932 | * An insecure source has sent us a dentry, here we verify it and dget() it. |
| 1933 | * This is used by ncpfs in its readdir implementation. |
| 1934 | * Zero is returned in the dentry is invalid. |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 1935 | * |
| 1936 | * 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] | 1937 | */ |
Nick Piggin | d3a23e1 | 2011-01-05 20:01:21 +1100 | [diff] [blame] | 1938 | int d_validate(struct dentry *dentry, struct dentry *dparent) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1939 | { |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 1940 | struct dentry *child; |
Nick Piggin | d3a23e1 | 2011-01-05 20:01:21 +1100 | [diff] [blame] | 1941 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1942 | spin_lock(&dparent->d_lock); |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 1943 | list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) { |
| 1944 | if (dentry == child) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1945 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 1946 | __dget_dlock(dentry); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1947 | spin_unlock(&dentry->d_lock); |
| 1948 | spin_unlock(&dparent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1949 | return 1; |
| 1950 | } |
| 1951 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 1952 | spin_unlock(&dparent->d_lock); |
Nick Piggin | 786a5e1 | 2011-01-07 17:49:16 +1100 | [diff] [blame] | 1953 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1954 | return 0; |
| 1955 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 1956 | EXPORT_SYMBOL(d_validate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1957 | |
| 1958 | /* |
| 1959 | * When a file is deleted, we have two options: |
| 1960 | * - turn this dentry into a negative dentry |
| 1961 | * - unhash this dentry and free it. |
| 1962 | * |
| 1963 | * Usually, we want to just turn this into |
| 1964 | * a negative dentry, but if anybody else is |
| 1965 | * currently using the dentry or the inode |
| 1966 | * we can't do that and we fall back on removing |
| 1967 | * it from the hash queues and waiting for |
| 1968 | * it to be deleted later when it has no users |
| 1969 | */ |
| 1970 | |
| 1971 | /** |
| 1972 | * d_delete - delete a dentry |
| 1973 | * @dentry: The dentry to delete |
| 1974 | * |
| 1975 | * Turn the dentry into a negative dentry if possible, otherwise |
| 1976 | * remove it from the hash queues so it can be deleted later |
| 1977 | */ |
| 1978 | |
| 1979 | void d_delete(struct dentry * dentry) |
| 1980 | { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1981 | struct inode *inode; |
John McCutchan | 7a91bf7 | 2005-08-08 13:52:16 -0400 | [diff] [blame] | 1982 | int isdir = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1983 | /* |
| 1984 | * Are we the only user? |
| 1985 | */ |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 1986 | again: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1987 | spin_lock(&dentry->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1988 | inode = dentry->d_inode; |
| 1989 | isdir = S_ISDIR(inode->i_mode); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 1990 | if (dentry->d_count == 1) { |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 1991 | if (inode && !spin_trylock(&inode->i_lock)) { |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 1992 | spin_unlock(&dentry->d_lock); |
| 1993 | cpu_relax(); |
| 1994 | goto again; |
| 1995 | } |
Al Viro | 13e3c5e | 2010-05-21 16:11:04 -0400 | [diff] [blame] | 1996 | dentry->d_flags &= ~DCACHE_CANT_MOUNT; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1997 | dentry_unlink_inode(dentry); |
John McCutchan | 7a91bf7 | 2005-08-08 13:52:16 -0400 | [diff] [blame] | 1998 | fsnotify_nameremove(dentry, isdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1999 | return; |
| 2000 | } |
| 2001 | |
| 2002 | if (!d_unhashed(dentry)) |
| 2003 | __d_drop(dentry); |
| 2004 | |
| 2005 | spin_unlock(&dentry->d_lock); |
John McCutchan | 7a91bf7 | 2005-08-08 13:52:16 -0400 | [diff] [blame] | 2006 | |
| 2007 | fsnotify_nameremove(dentry, isdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2008 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2009 | EXPORT_SYMBOL(d_delete); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2010 | |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 2011 | static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2012 | { |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 2013 | BUG_ON(!d_unhashed(entry)); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 2014 | hlist_bl_lock(b); |
Linus Torvalds | dea3667 | 2011-04-24 07:58:46 -0700 | [diff] [blame] | 2015 | entry->d_flags |= DCACHE_RCUACCESS; |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 2016 | hlist_bl_add_head_rcu(&entry->d_hash, b); |
Christoph Hellwig | 1879fd6 | 2011-04-25 14:01:36 -0400 | [diff] [blame] | 2017 | hlist_bl_unlock(b); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2018 | } |
| 2019 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2020 | static void _d_rehash(struct dentry * entry) |
| 2021 | { |
| 2022 | __d_rehash(entry, d_hash(entry->d_parent, entry->d_name.hash)); |
| 2023 | } |
| 2024 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2025 | /** |
| 2026 | * d_rehash - add an entry back to the hash |
| 2027 | * @entry: dentry to add to the hash |
| 2028 | * |
| 2029 | * Adds a dentry to the hash according to its name. |
| 2030 | */ |
| 2031 | |
| 2032 | void d_rehash(struct dentry * entry) |
| 2033 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2034 | spin_lock(&entry->d_lock); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2035 | _d_rehash(entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2036 | spin_unlock(&entry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2037 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2038 | EXPORT_SYMBOL(d_rehash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2039 | |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2040 | /** |
| 2041 | * dentry_update_name_case - update case insensitive dentry with a new name |
| 2042 | * @dentry: dentry to be updated |
| 2043 | * @name: new name |
| 2044 | * |
| 2045 | * Update a case insensitive dentry with new case of name. |
| 2046 | * |
| 2047 | * dentry must have been returned by d_lookup with name @name. Old and new |
| 2048 | * name lengths must match (ie. no d_compare which allows mismatched name |
| 2049 | * lengths). |
| 2050 | * |
| 2051 | * Parent inode i_mutex must be held over d_lookup and into this call (to |
| 2052 | * keep renames and concurrent inserts, and readdir(2) away). |
| 2053 | */ |
| 2054 | void dentry_update_name_case(struct dentry *dentry, struct qstr *name) |
| 2055 | { |
Linus Torvalds | 7ebfa57 | 2011-04-15 07:34:26 -0700 | [diff] [blame] | 2056 | BUG_ON(!mutex_is_locked(&dentry->d_parent->d_inode->i_mutex)); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2057 | BUG_ON(dentry->d_name.len != name->len); /* d_lookup gives this */ |
| 2058 | |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2059 | spin_lock(&dentry->d_lock); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2060 | write_seqcount_begin(&dentry->d_seq); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2061 | memcpy((unsigned char *)dentry->d_name.name, name->name, name->len); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2062 | write_seqcount_end(&dentry->d_seq); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2063 | spin_unlock(&dentry->d_lock); |
Nick Piggin | fb2d5b8 | 2011-01-07 17:49:26 +1100 | [diff] [blame] | 2064 | } |
| 2065 | EXPORT_SYMBOL(dentry_update_name_case); |
| 2066 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2067 | static void switch_names(struct dentry *dentry, struct dentry *target) |
| 2068 | { |
| 2069 | if (dname_external(target)) { |
| 2070 | if (dname_external(dentry)) { |
| 2071 | /* |
| 2072 | * Both external: swap the pointers |
| 2073 | */ |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2074 | swap(target->d_name.name, dentry->d_name.name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2075 | } else { |
| 2076 | /* |
| 2077 | * dentry:internal, target:external. Steal target's |
| 2078 | * storage and make target internal. |
| 2079 | */ |
J. Bruce Fields | 321bcf9 | 2007-10-21 16:41:38 -0700 | [diff] [blame] | 2080 | memcpy(target->d_iname, dentry->d_name.name, |
| 2081 | dentry->d_name.len + 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2082 | dentry->d_name.name = target->d_name.name; |
| 2083 | target->d_name.name = target->d_iname; |
| 2084 | } |
| 2085 | } else { |
| 2086 | if (dname_external(dentry)) { |
| 2087 | /* |
| 2088 | * dentry:external, target:internal. Give dentry's |
| 2089 | * storage to target and make dentry internal |
| 2090 | */ |
| 2091 | memcpy(dentry->d_iname, target->d_name.name, |
| 2092 | target->d_name.len + 1); |
| 2093 | target->d_name.name = dentry->d_name.name; |
| 2094 | dentry->d_name.name = dentry->d_iname; |
| 2095 | } else { |
| 2096 | /* |
| 2097 | * Both are internal. Just copy target to dentry |
| 2098 | */ |
| 2099 | memcpy(dentry->d_iname, target->d_name.name, |
| 2100 | target->d_name.len + 1); |
Al Viro | dc711ca | 2008-11-03 15:03:50 -0500 | [diff] [blame] | 2101 | dentry->d_name.len = target->d_name.len; |
| 2102 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2103 | } |
| 2104 | } |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2105 | swap(dentry->d_name.len, target->d_name.len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2106 | } |
| 2107 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2108 | static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target) |
| 2109 | { |
| 2110 | /* |
| 2111 | * XXXX: do we really need to take target->d_lock? |
| 2112 | */ |
| 2113 | if (IS_ROOT(dentry) || dentry->d_parent == target->d_parent) |
| 2114 | spin_lock(&target->d_parent->d_lock); |
| 2115 | else { |
| 2116 | if (d_ancestor(dentry->d_parent, target->d_parent)) { |
| 2117 | spin_lock(&dentry->d_parent->d_lock); |
| 2118 | spin_lock_nested(&target->d_parent->d_lock, |
| 2119 | DENTRY_D_LOCK_NESTED); |
| 2120 | } else { |
| 2121 | spin_lock(&target->d_parent->d_lock); |
| 2122 | spin_lock_nested(&dentry->d_parent->d_lock, |
| 2123 | DENTRY_D_LOCK_NESTED); |
| 2124 | } |
| 2125 | } |
| 2126 | if (target < dentry) { |
| 2127 | spin_lock_nested(&target->d_lock, 2); |
| 2128 | spin_lock_nested(&dentry->d_lock, 3); |
| 2129 | } else { |
| 2130 | spin_lock_nested(&dentry->d_lock, 2); |
| 2131 | spin_lock_nested(&target->d_lock, 3); |
| 2132 | } |
| 2133 | } |
| 2134 | |
| 2135 | static void dentry_unlock_parents_for_move(struct dentry *dentry, |
| 2136 | struct dentry *target) |
| 2137 | { |
| 2138 | if (target->d_parent != dentry->d_parent) |
| 2139 | spin_unlock(&dentry->d_parent->d_lock); |
| 2140 | if (target->d_parent != target) |
| 2141 | spin_unlock(&target->d_parent->d_lock); |
| 2142 | } |
| 2143 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2144 | /* |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2145 | * When switching names, the actual string doesn't strictly have to |
| 2146 | * be preserved in the target - because we're dropping the target |
| 2147 | * anyway. As such, we can just do a simple memcpy() to copy over |
| 2148 | * the new name before we switch. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2149 | * |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2150 | * Note that we have to be a lot more careful about getting the hash |
| 2151 | * switched - we have to switch the hash value properly even if it |
| 2152 | * then no longer matches the actual (corrupted) string of the target. |
| 2153 | * 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] | 2154 | */ |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2155 | /* |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2156 | * __d_move - move a dentry |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2157 | * @dentry: entry to move |
| 2158 | * @target: new dentry |
| 2159 | * |
| 2160 | * Update the dcache to reflect the move of a file name. Negative |
Jeff Layton | c46c887 | 2011-07-26 13:33:16 -0400 | [diff] [blame] | 2161 | * dcache entries should not be moved in this way. Caller must hold |
| 2162 | * rename_lock, the i_mutex of the source and target directories, |
| 2163 | * 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] | 2164 | */ |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2165 | static void __d_move(struct dentry * dentry, struct dentry * target) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2166 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2167 | if (!dentry->d_inode) |
| 2168 | printk(KERN_WARNING "VFS: moving negative dcache entry\n"); |
| 2169 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2170 | BUG_ON(d_ancestor(dentry, target)); |
| 2171 | BUG_ON(d_ancestor(target, dentry)); |
| 2172 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2173 | dentry_lock_for_move(dentry, target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2174 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2175 | write_seqcount_begin(&dentry->d_seq); |
| 2176 | write_seqcount_begin(&target->d_seq); |
| 2177 | |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 2178 | /* __d_drop does write_seqcount_barrier, but they're OK to nest. */ |
| 2179 | |
| 2180 | /* |
| 2181 | * Move the dentry to the target hash queue. Don't bother checking |
| 2182 | * for the same hash queue because of how unlikely it is. |
| 2183 | */ |
| 2184 | __d_drop(dentry); |
Nick Piggin | 789680d | 2011-01-07 17:49:30 +1100 | [diff] [blame] | 2185 | __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2186 | |
| 2187 | /* Unhash the target: dput() will then get rid of it */ |
| 2188 | __d_drop(target); |
| 2189 | |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2190 | list_del(&dentry->d_u.d_child); |
| 2191 | list_del(&target->d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2192 | |
| 2193 | /* Switch the names.. */ |
| 2194 | switch_names(dentry, target); |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2195 | swap(dentry->d_name.hash, target->d_name.hash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2196 | |
| 2197 | /* ... and switch the parents */ |
| 2198 | if (IS_ROOT(dentry)) { |
| 2199 | dentry->d_parent = target->d_parent; |
| 2200 | target->d_parent = target; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2201 | INIT_LIST_HEAD(&target->d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2202 | } else { |
Wu Fengguang | 9a8d5bb | 2009-01-07 18:09:14 -0800 | [diff] [blame] | 2203 | swap(dentry->d_parent, target->d_parent); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2204 | |
| 2205 | /* And add them back to the (new) parent lists */ |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2206 | list_add(&target->d_u.d_child, &target->d_parent->d_subdirs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2207 | } |
| 2208 | |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2209 | list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2210 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2211 | write_seqcount_end(&target->d_seq); |
| 2212 | write_seqcount_end(&dentry->d_seq); |
| 2213 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2214 | dentry_unlock_parents_for_move(dentry, target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2215 | spin_unlock(&target->d_lock); |
Nick Piggin | c32ccd8 | 2006-03-25 03:07:09 -0800 | [diff] [blame] | 2216 | fsnotify_d_move(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2217 | spin_unlock(&dentry->d_lock); |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2218 | } |
| 2219 | |
| 2220 | /* |
| 2221 | * d_move - move a dentry |
| 2222 | * @dentry: entry to move |
| 2223 | * @target: new dentry |
| 2224 | * |
| 2225 | * Update the dcache to reflect the move of a file name. Negative |
Jeff Layton | c46c887 | 2011-07-26 13:33:16 -0400 | [diff] [blame] | 2226 | * dcache entries should not be moved in this way. See the locking |
| 2227 | * requirements for __d_move. |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2228 | */ |
| 2229 | void d_move(struct dentry *dentry, struct dentry *target) |
| 2230 | { |
| 2231 | write_seqlock(&rename_lock); |
| 2232 | __d_move(dentry, target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2233 | write_sequnlock(&rename_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2234 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2235 | EXPORT_SYMBOL(d_move); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2236 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2237 | /** |
| 2238 | * d_ancestor - search for an ancestor |
| 2239 | * @p1: ancestor dentry |
| 2240 | * @p2: child dentry |
| 2241 | * |
| 2242 | * Returns the ancestor dentry of p2 which is a child of p1, if p1 is |
| 2243 | * an ancestor of p2, else NULL. |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2244 | */ |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2245 | struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2246 | { |
| 2247 | struct dentry *p; |
| 2248 | |
OGAWA Hirofumi | 871c006 | 2008-10-16 07:50:27 +0900 | [diff] [blame] | 2249 | for (p = p2; !IS_ROOT(p); p = p->d_parent) { |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2250 | if (p->d_parent == p1) |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2251 | return p; |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2252 | } |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2253 | return NULL; |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2254 | } |
| 2255 | |
| 2256 | /* |
| 2257 | * This helper attempts to cope with remotely renamed directories |
| 2258 | * |
| 2259 | * It assumes that the caller is already holding |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2260 | * 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] | 2261 | * |
| 2262 | * Note: If ever the locking in lock_rename() changes, then please |
| 2263 | * remember to update this too... |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2264 | */ |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2265 | static struct dentry *__d_unalias(struct inode *inode, |
| 2266 | struct dentry *dentry, struct dentry *alias) |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2267 | { |
| 2268 | struct mutex *m1 = NULL, *m2 = NULL; |
| 2269 | struct dentry *ret; |
| 2270 | |
| 2271 | /* If alias and dentry share a parent, then no extra locks required */ |
| 2272 | if (alias->d_parent == dentry->d_parent) |
| 2273 | goto out_unalias; |
| 2274 | |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2275 | /* See lock_rename() */ |
| 2276 | ret = ERR_PTR(-EBUSY); |
| 2277 | if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) |
| 2278 | goto out_err; |
| 2279 | m1 = &dentry->d_sb->s_vfs_rename_mutex; |
| 2280 | if (!mutex_trylock(&alias->d_parent->d_inode->i_mutex)) |
| 2281 | goto out_err; |
| 2282 | m2 = &alias->d_parent->d_inode->i_mutex; |
| 2283 | out_unalias: |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2284 | __d_move(alias, dentry); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2285 | ret = alias; |
| 2286 | out_err: |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2287 | spin_unlock(&inode->i_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2288 | if (m2) |
| 2289 | mutex_unlock(m2); |
| 2290 | if (m1) |
| 2291 | mutex_unlock(m1); |
| 2292 | return ret; |
| 2293 | } |
| 2294 | |
| 2295 | /* |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2296 | * Prepare an anonymous dentry for life in the superblock's dentry tree as a |
| 2297 | * named dentry in place of the dentry to be replaced. |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2298 | * returns with anon->d_lock held! |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2299 | */ |
| 2300 | static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon) |
| 2301 | { |
| 2302 | struct dentry *dparent, *aparent; |
| 2303 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2304 | dentry_lock_for_move(anon, dentry); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2305 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2306 | write_seqcount_begin(&dentry->d_seq); |
| 2307 | write_seqcount_begin(&anon->d_seq); |
| 2308 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2309 | dparent = dentry->d_parent; |
| 2310 | aparent = anon->d_parent; |
| 2311 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2312 | switch_names(dentry, anon); |
| 2313 | swap(dentry->d_name.hash, anon->d_name.hash); |
| 2314 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2315 | dentry->d_parent = (aparent == anon) ? dentry : aparent; |
| 2316 | list_del(&dentry->d_u.d_child); |
| 2317 | if (!IS_ROOT(dentry)) |
| 2318 | list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); |
| 2319 | else |
| 2320 | INIT_LIST_HEAD(&dentry->d_u.d_child); |
| 2321 | |
| 2322 | anon->d_parent = (dparent == dentry) ? anon : dparent; |
| 2323 | list_del(&anon->d_u.d_child); |
| 2324 | if (!IS_ROOT(anon)) |
| 2325 | list_add(&anon->d_u.d_child, &anon->d_parent->d_subdirs); |
| 2326 | else |
| 2327 | INIT_LIST_HEAD(&anon->d_u.d_child); |
| 2328 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2329 | write_seqcount_end(&dentry->d_seq); |
| 2330 | write_seqcount_end(&anon->d_seq); |
| 2331 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2332 | dentry_unlock_parents_for_move(anon, dentry); |
| 2333 | spin_unlock(&dentry->d_lock); |
| 2334 | |
| 2335 | /* anon->d_lock still locked, returns locked */ |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2336 | anon->d_flags &= ~DCACHE_DISCONNECTED; |
| 2337 | } |
| 2338 | |
| 2339 | /** |
| 2340 | * d_materialise_unique - introduce an inode into the tree |
| 2341 | * @dentry: candidate dentry |
| 2342 | * @inode: inode to bind to the dentry, to which aliases may be attached |
| 2343 | * |
| 2344 | * Introduces an dentry into the tree, substituting an extant disconnected |
Jeff Layton | c46c887 | 2011-07-26 13:33:16 -0400 | [diff] [blame] | 2345 | * root directory alias in its place if there is one. Caller must hold the |
| 2346 | * i_mutex of the parent directory. |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2347 | */ |
| 2348 | struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) |
| 2349 | { |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2350 | struct dentry *actual; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2351 | |
| 2352 | BUG_ON(!d_unhashed(dentry)); |
| 2353 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2354 | if (!inode) { |
| 2355 | actual = dentry; |
OGAWA Hirofumi | 360da90 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2356 | __d_instantiate(dentry, NULL); |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2357 | d_rehash(actual); |
| 2358 | goto out_nolock; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2359 | } |
| 2360 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2361 | spin_lock(&inode->i_lock); |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2362 | |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2363 | if (S_ISDIR(inode->i_mode)) { |
| 2364 | struct dentry *alias; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2365 | |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2366 | /* Does an aliased dentry already exist? */ |
| 2367 | alias = __d_find_alias(inode, 0); |
| 2368 | if (alias) { |
| 2369 | actual = alias; |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2370 | write_seqlock(&rename_lock); |
| 2371 | |
| 2372 | if (d_ancestor(alias, dentry)) { |
| 2373 | /* Check for loops */ |
| 2374 | actual = ERR_PTR(-ELOOP); |
| 2375 | } else if (IS_ROOT(alias)) { |
| 2376 | /* Is this an anonymous mountpoint that we |
| 2377 | * could splice into our tree? */ |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2378 | __d_materialise_dentry(dentry, alias); |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2379 | write_sequnlock(&rename_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2380 | __d_drop(alias); |
| 2381 | goto found; |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2382 | } else { |
| 2383 | /* Nope, but we must(!) avoid directory |
| 2384 | * aliasing */ |
| 2385 | actual = __d_unalias(inode, dentry, alias); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2386 | } |
Al Viro | 1836750 | 2011-07-12 21:42:24 -0400 | [diff] [blame] | 2387 | write_sequnlock(&rename_lock); |
David Howells | dd17994 | 2011-08-16 15:31:30 +0100 | [diff] [blame] | 2388 | if (IS_ERR(actual)) { |
| 2389 | if (PTR_ERR(actual) == -ELOOP) |
| 2390 | pr_warn_ratelimited( |
| 2391 | "VFS: Lookup of '%s' in %s %s" |
| 2392 | " would have caused loop\n", |
| 2393 | dentry->d_name.name, |
| 2394 | inode->i_sb->s_type->name, |
| 2395 | inode->i_sb->s_id); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2396 | dput(alias); |
David Howells | dd17994 | 2011-08-16 15:31:30 +0100 | [diff] [blame] | 2397 | } |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2398 | goto out_nolock; |
| 2399 | } |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2400 | } |
| 2401 | |
| 2402 | /* Add a unique reference */ |
| 2403 | actual = __d_instantiate_unique(dentry, inode); |
| 2404 | if (!actual) |
| 2405 | actual = dentry; |
Nick Piggin | 357f8e6 | 2011-01-07 17:49:42 +1100 | [diff] [blame] | 2406 | else |
| 2407 | BUG_ON(!d_unhashed(actual)); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2408 | |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2409 | spin_lock(&actual->d_lock); |
| 2410 | found: |
| 2411 | _d_rehash(actual); |
| 2412 | spin_unlock(&actual->d_lock); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 2413 | spin_unlock(&inode->i_lock); |
Trond Myklebust | 9eaef27 | 2006-10-21 10:24:20 -0700 | [diff] [blame] | 2414 | out_nolock: |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2415 | if (actual == dentry) { |
| 2416 | security_d_instantiate(dentry, inode); |
| 2417 | return NULL; |
| 2418 | } |
| 2419 | |
| 2420 | iput(inode); |
| 2421 | return actual; |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2422 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2423 | EXPORT_SYMBOL_GPL(d_materialise_unique); |
David Howells | 770bfad | 2006-08-22 20:06:07 -0400 | [diff] [blame] | 2424 | |
Miklos Szeredi | cdd16d0 | 2008-06-23 18:11:53 +0200 | [diff] [blame] | 2425 | static int prepend(char **buffer, int *buflen, const char *str, int namelen) |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2426 | { |
| 2427 | *buflen -= namelen; |
| 2428 | if (*buflen < 0) |
| 2429 | return -ENAMETOOLONG; |
| 2430 | *buffer -= namelen; |
| 2431 | memcpy(*buffer, str, namelen); |
| 2432 | return 0; |
| 2433 | } |
| 2434 | |
Miklos Szeredi | cdd16d0 | 2008-06-23 18:11:53 +0200 | [diff] [blame] | 2435 | static int prepend_name(char **buffer, int *buflen, struct qstr *name) |
| 2436 | { |
| 2437 | return prepend(buffer, buflen, name->name, name->len); |
| 2438 | } |
| 2439 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2440 | /** |
Randy Dunlap | 208898c | 2010-11-18 15:02:49 -0800 | [diff] [blame] | 2441 | * prepend_path - Prepend path string to a buffer |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2442 | * @path: the dentry/vfsmount to report |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2443 | * @root: root vfsmnt/dentry |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2444 | * @buffer: pointer to the end of the buffer |
| 2445 | * @buflen: pointer to buffer length |
| 2446 | * |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2447 | * Caller holds the rename_lock. |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2448 | */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2449 | static int prepend_path(const struct path *path, |
| 2450 | const struct path *root, |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2451 | char **buffer, int *buflen) |
| 2452 | { |
| 2453 | struct dentry *dentry = path->dentry; |
| 2454 | struct vfsmount *vfsmnt = path->mnt; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame^] | 2455 | struct mount *mnt = real_mount(vfsmnt); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2456 | bool slash = false; |
| 2457 | int error = 0; |
| 2458 | |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 2459 | br_read_lock(vfsmount_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2460 | while (dentry != root->dentry || vfsmnt != root->mnt) { |
| 2461 | struct dentry * parent; |
| 2462 | |
| 2463 | if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { |
| 2464 | /* Global root? */ |
Al Viro | 676da58 | 2011-11-24 21:47:05 -0500 | [diff] [blame] | 2465 | if (!mnt_has_parent(mnt)) |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2466 | goto global_root; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame^] | 2467 | dentry = mnt->mnt.mnt_mountpoint; |
| 2468 | mnt = mnt->mnt_parent; |
| 2469 | vfsmnt = &mnt->mnt; |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2470 | continue; |
| 2471 | } |
| 2472 | parent = dentry->d_parent; |
| 2473 | prefetch(parent); |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2474 | spin_lock(&dentry->d_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2475 | error = prepend_name(buffer, buflen, &dentry->d_name); |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2476 | spin_unlock(&dentry->d_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2477 | if (!error) |
| 2478 | error = prepend(buffer, buflen, "/", 1); |
| 2479 | if (error) |
| 2480 | break; |
| 2481 | |
| 2482 | slash = true; |
| 2483 | dentry = parent; |
| 2484 | } |
| 2485 | |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2486 | if (!error && !slash) |
| 2487 | error = prepend(buffer, buflen, "/", 1); |
| 2488 | |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2489 | out: |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 2490 | br_read_unlock(vfsmount_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2491 | return error; |
| 2492 | |
| 2493 | global_root: |
| 2494 | /* |
| 2495 | * Filesystems needing to implement special "root names" |
| 2496 | * should do so with ->d_dname() |
| 2497 | */ |
| 2498 | if (IS_ROOT(dentry) && |
| 2499 | (dentry->d_name.len != 1 || dentry->d_name.name[0] != '/')) { |
| 2500 | WARN(1, "Root dentry has weird name <%.*s>\n", |
| 2501 | (int) dentry->d_name.len, dentry->d_name.name); |
| 2502 | } |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2503 | if (!slash) |
| 2504 | error = prepend(buffer, buflen, "/", 1); |
| 2505 | if (!error) |
| 2506 | error = vfsmnt->mnt_ns ? 1 : 2; |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2507 | goto out; |
| 2508 | } |
| 2509 | |
| 2510 | /** |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 2511 | * __d_path - return the path of a dentry |
Miklos Szeredi | 9d1bc601 | 2008-03-27 13:06:21 +0100 | [diff] [blame] | 2512 | * @path: the dentry/vfsmount to report |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2513 | * @root: root vfsmnt/dentry |
Randy Dunlap | cd956a1 | 2010-08-14 13:05:31 -0700 | [diff] [blame] | 2514 | * @buf: buffer to return value in |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2515 | * @buflen: buffer length |
| 2516 | * |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2517 | * Convert a dentry into an ASCII path name. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2518 | * |
Arjan van de Ven | 52afeef | 2008-12-01 14:35:00 -0800 | [diff] [blame] | 2519 | * Returns a pointer into the buffer or an error code if the |
| 2520 | * path was too long. |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2521 | * |
Christoph Hellwig | be14824 | 2010-10-10 05:36:21 -0400 | [diff] [blame] | 2522 | * "buflen" should be positive. |
Miklos Szeredi | 9d1bc601 | 2008-03-27 13:06:21 +0100 | [diff] [blame] | 2523 | * |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2524 | * If the path is not reachable from the supplied root, return %NULL. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2525 | */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2526 | char *__d_path(const struct path *path, |
| 2527 | const struct path *root, |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2528 | char *buf, int buflen) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2529 | { |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2530 | char *res = buf + buflen; |
| 2531 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2532 | |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2533 | prepend(&res, &buflen, "\0", 1); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2534 | write_seqlock(&rename_lock); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2535 | error = prepend_path(path, root, &res, &buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2536 | write_sequnlock(&rename_lock); |
Christoph Hellwig | be14824 | 2010-10-10 05:36:21 -0400 | [diff] [blame] | 2537 | |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2538 | if (error < 0) |
| 2539 | return ERR_PTR(error); |
| 2540 | if (error > 0) |
| 2541 | return NULL; |
| 2542 | return res; |
| 2543 | } |
| 2544 | |
| 2545 | char *d_absolute_path(const struct path *path, |
| 2546 | char *buf, int buflen) |
| 2547 | { |
| 2548 | struct path root = {}; |
| 2549 | char *res = buf + buflen; |
| 2550 | int error; |
| 2551 | |
| 2552 | prepend(&res, &buflen, "\0", 1); |
| 2553 | write_seqlock(&rename_lock); |
| 2554 | error = prepend_path(path, &root, &res, &buflen); |
| 2555 | write_sequnlock(&rename_lock); |
| 2556 | |
| 2557 | if (error > 1) |
| 2558 | error = -EINVAL; |
| 2559 | if (error < 0) |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2560 | return ERR_PTR(error); |
Miklos Szeredi | f2eb657 | 2010-08-10 11:41:39 +0200 | [diff] [blame] | 2561 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2562 | } |
| 2563 | |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2564 | /* |
| 2565 | * same as __d_path but appends "(deleted)" for unlinked files. |
| 2566 | */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2567 | static int path_with_deleted(const struct path *path, |
| 2568 | const struct path *root, |
| 2569 | char **buf, int *buflen) |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2570 | { |
| 2571 | prepend(buf, buflen, "\0", 1); |
| 2572 | if (d_unlinked(path->dentry)) { |
| 2573 | int error = prepend(buf, buflen, " (deleted)", 10); |
| 2574 | if (error) |
| 2575 | return error; |
| 2576 | } |
| 2577 | |
| 2578 | return prepend_path(path, root, buf, buflen); |
| 2579 | } |
| 2580 | |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2581 | static int prepend_unreachable(char **buffer, int *buflen) |
| 2582 | { |
| 2583 | return prepend(buffer, buflen, "(unreachable)", 13); |
| 2584 | } |
| 2585 | |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2586 | /** |
| 2587 | * d_path - return the path of a dentry |
Jan Blunck | cf28b48 | 2008-02-14 19:38:44 -0800 | [diff] [blame] | 2588 | * @path: path to report |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2589 | * @buf: buffer to return value in |
| 2590 | * @buflen: buffer length |
| 2591 | * |
| 2592 | * Convert a dentry into an ASCII path name. If the entry has been deleted |
| 2593 | * the string " (deleted)" is appended. Note that this is ambiguous. |
| 2594 | * |
Arjan van de Ven | 52afeef | 2008-12-01 14:35:00 -0800 | [diff] [blame] | 2595 | * Returns a pointer into the buffer or an error code if the path was |
| 2596 | * too long. Note: Callers should use the returned pointer, not the passed |
| 2597 | * in buffer, to use the name! The implementation often starts at an offset |
| 2598 | * into the buffer, and may leave 0 bytes at the start. |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2599 | * |
Miklos Szeredi | 31f3e0b | 2008-06-23 18:11:52 +0200 | [diff] [blame] | 2600 | * "buflen" should be positive. |
Jan Blunck | a03a8a70 | 2008-02-14 19:38:32 -0800 | [diff] [blame] | 2601 | */ |
Jan Engelhardt | 20d4fdc | 2008-06-09 16:40:36 -0700 | [diff] [blame] | 2602 | char *d_path(const struct path *path, char *buf, int buflen) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2603 | { |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2604 | char *res = buf + buflen; |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2605 | struct path root; |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2606 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2607 | |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2608 | /* |
| 2609 | * We have various synthetic filesystems that never get mounted. On |
| 2610 | * these filesystems dentries are never used for lookup purposes, and |
| 2611 | * thus don't need to be hashed. They also don't need a name until a |
| 2612 | * user wants to identify the object in /proc/pid/fd/. The little hack |
| 2613 | * below allows us to generate a name for these objects on demand: |
| 2614 | */ |
Jan Blunck | cf28b48 | 2008-02-14 19:38:44 -0800 | [diff] [blame] | 2615 | if (path->dentry->d_op && path->dentry->d_op->d_dname) |
| 2616 | return path->dentry->d_op->d_dname(path->dentry, buf, buflen); |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2617 | |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 2618 | get_fs_root(current->fs, &root); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2619 | write_seqlock(&rename_lock); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2620 | error = path_with_deleted(path, &root, &res, &buflen); |
| 2621 | if (error < 0) |
Miklos Szeredi | ffd1f4e | 2010-08-10 11:41:40 +0200 | [diff] [blame] | 2622 | res = ERR_PTR(error); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2623 | write_sequnlock(&rename_lock); |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2624 | path_put(&root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2625 | return res; |
| 2626 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2627 | EXPORT_SYMBOL(d_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2628 | |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2629 | /** |
| 2630 | * d_path_with_unreachable - return the path of a dentry |
| 2631 | * @path: path to report |
| 2632 | * @buf: buffer to return value in |
| 2633 | * @buflen: buffer length |
| 2634 | * |
| 2635 | * The difference from d_path() is that this prepends "(unreachable)" |
| 2636 | * to paths which are unreachable from the current process' root. |
| 2637 | */ |
| 2638 | char *d_path_with_unreachable(const struct path *path, char *buf, int buflen) |
| 2639 | { |
| 2640 | char *res = buf + buflen; |
| 2641 | struct path root; |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2642 | int error; |
| 2643 | |
| 2644 | if (path->dentry->d_op && path->dentry->d_op->d_dname) |
| 2645 | return path->dentry->d_op->d_dname(path->dentry, buf, buflen); |
| 2646 | |
| 2647 | get_fs_root(current->fs, &root); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2648 | write_seqlock(&rename_lock); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2649 | error = path_with_deleted(path, &root, &res, &buflen); |
| 2650 | if (error > 0) |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2651 | error = prepend_unreachable(&res, &buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2652 | write_sequnlock(&rename_lock); |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2653 | path_put(&root); |
| 2654 | if (error) |
| 2655 | res = ERR_PTR(error); |
| 2656 | |
| 2657 | return res; |
| 2658 | } |
| 2659 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2660 | /* |
Eric Dumazet | c23fbb6 | 2007-05-08 00:26:18 -0700 | [diff] [blame] | 2661 | * Helper function for dentry_operations.d_dname() members |
| 2662 | */ |
| 2663 | char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen, |
| 2664 | const char *fmt, ...) |
| 2665 | { |
| 2666 | va_list args; |
| 2667 | char temp[64]; |
| 2668 | int sz; |
| 2669 | |
| 2670 | va_start(args, fmt); |
| 2671 | sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1; |
| 2672 | va_end(args); |
| 2673 | |
| 2674 | if (sz > sizeof(temp) || sz > buflen) |
| 2675 | return ERR_PTR(-ENAMETOOLONG); |
| 2676 | |
| 2677 | buffer += buflen - sz; |
| 2678 | return memcpy(buffer, temp, sz); |
| 2679 | } |
| 2680 | |
| 2681 | /* |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2682 | * Write full pathname from the root of the filesystem into the buffer. |
| 2683 | */ |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2684 | static char *__dentry_path(struct dentry *dentry, char *buf, int buflen) |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2685 | { |
| 2686 | char *end = buf + buflen; |
| 2687 | char *retval; |
| 2688 | |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2689 | prepend(&end, &buflen, "\0", 1); |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2690 | if (buflen < 1) |
| 2691 | goto Elong; |
| 2692 | /* Get '/' right */ |
| 2693 | retval = end-1; |
| 2694 | *retval = '/'; |
| 2695 | |
Miklos Szeredi | cdd16d0 | 2008-06-23 18:11:53 +0200 | [diff] [blame] | 2696 | while (!IS_ROOT(dentry)) { |
| 2697 | struct dentry *parent = dentry->d_parent; |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2698 | int error; |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2699 | |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2700 | prefetch(parent); |
Nick Piggin | 9abca36 | 2011-01-07 17:49:36 +1100 | [diff] [blame] | 2701 | spin_lock(&dentry->d_lock); |
| 2702 | error = prepend_name(&end, &buflen, &dentry->d_name); |
| 2703 | spin_unlock(&dentry->d_lock); |
| 2704 | if (error != 0 || prepend(&end, &buflen, "/", 1) != 0) |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2705 | goto Elong; |
| 2706 | |
| 2707 | retval = end; |
| 2708 | dentry = parent; |
| 2709 | } |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2710 | return retval; |
| 2711 | Elong: |
| 2712 | return ERR_PTR(-ENAMETOOLONG); |
| 2713 | } |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2714 | |
| 2715 | char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen) |
| 2716 | { |
| 2717 | char *retval; |
| 2718 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2719 | write_seqlock(&rename_lock); |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2720 | retval = __dentry_path(dentry, buf, buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2721 | write_sequnlock(&rename_lock); |
Nick Piggin | ec2447c | 2011-01-07 17:49:29 +1100 | [diff] [blame] | 2722 | |
| 2723 | return retval; |
| 2724 | } |
| 2725 | EXPORT_SYMBOL(dentry_path_raw); |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2726 | |
| 2727 | char *dentry_path(struct dentry *dentry, char *buf, int buflen) |
| 2728 | { |
| 2729 | char *p = NULL; |
| 2730 | char *retval; |
| 2731 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2732 | write_seqlock(&rename_lock); |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2733 | if (d_unlinked(dentry)) { |
| 2734 | p = buf + buflen; |
| 2735 | if (prepend(&p, &buflen, "//deleted", 10) != 0) |
| 2736 | goto Elong; |
| 2737 | buflen++; |
| 2738 | } |
| 2739 | retval = __dentry_path(dentry, buf, buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2740 | write_sequnlock(&rename_lock); |
Al Viro | c103135 | 2010-06-06 22:31:14 -0400 | [diff] [blame] | 2741 | if (!IS_ERR(retval) && p) |
| 2742 | *p = '/'; /* restore '/' overriden with '\0' */ |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2743 | return retval; |
| 2744 | Elong: |
Ram Pai | 6092d04 | 2008-03-27 13:06:20 +0100 | [diff] [blame] | 2745 | return ERR_PTR(-ENAMETOOLONG); |
| 2746 | } |
| 2747 | |
| 2748 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2749 | * NOTE! The user-level library version returns a |
| 2750 | * character pointer. The kernel system call just |
| 2751 | * returns the length of the buffer filled (which |
| 2752 | * includes the ending '\0' character), or a negative |
| 2753 | * error value. So libc would do something like |
| 2754 | * |
| 2755 | * char *getcwd(char * buf, size_t size) |
| 2756 | * { |
| 2757 | * int retval; |
| 2758 | * |
| 2759 | * retval = sys_getcwd(buf, size); |
| 2760 | * if (retval >= 0) |
| 2761 | * return buf; |
| 2762 | * errno = -retval; |
| 2763 | * return NULL; |
| 2764 | * } |
| 2765 | */ |
Heiko Carstens | 3cdad42 | 2009-01-14 14:14:22 +0100 | [diff] [blame] | 2766 | SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2767 | { |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2768 | int error; |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2769 | struct path pwd, root; |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2770 | char *page = (char *) __get_free_page(GFP_USER); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2771 | |
| 2772 | if (!page) |
| 2773 | return -ENOMEM; |
| 2774 | |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 2775 | get_fs_root_and_pwd(current->fs, &root, &pwd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2776 | |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2777 | error = -ENOENT; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2778 | write_seqlock(&rename_lock); |
Alexey Dobriyan | f3da392 | 2009-05-04 03:32:03 +0400 | [diff] [blame] | 2779 | if (!d_unlinked(pwd.dentry)) { |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2780 | unsigned long len; |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2781 | char *cwd = page + PAGE_SIZE; |
| 2782 | int buflen = PAGE_SIZE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2783 | |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2784 | prepend(&cwd, &buflen, "\0", 1); |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2785 | error = prepend_path(&pwd, &root, &cwd, &buflen); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2786 | write_sequnlock(&rename_lock); |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2787 | |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2788 | if (error < 0) |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2789 | goto out; |
| 2790 | |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2791 | /* Unreachable from current root */ |
Al Viro | 02125a8 | 2011-12-05 08:43:34 -0500 | [diff] [blame] | 2792 | if (error > 0) { |
Miklos Szeredi | 8df9d1a | 2010-08-10 11:41:41 +0200 | [diff] [blame] | 2793 | error = prepend_unreachable(&cwd, &buflen); |
| 2794 | if (error) |
| 2795 | goto out; |
| 2796 | } |
| 2797 | |
Linus Torvalds | 552ce54 | 2007-02-13 12:08:18 -0800 | [diff] [blame] | 2798 | error = -ERANGE; |
| 2799 | len = PAGE_SIZE + page - cwd; |
| 2800 | if (len <= size) { |
| 2801 | error = len; |
| 2802 | if (copy_to_user(buf, cwd, len)) |
| 2803 | error = -EFAULT; |
| 2804 | } |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2805 | } else { |
| 2806 | write_sequnlock(&rename_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2807 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2808 | |
| 2809 | out: |
Jan Blunck | 6ac08c3 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 2810 | path_put(&pwd); |
| 2811 | path_put(&root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2812 | free_page((unsigned long) page); |
| 2813 | return error; |
| 2814 | } |
| 2815 | |
| 2816 | /* |
| 2817 | * Test whether new_dentry is a subdirectory of old_dentry. |
| 2818 | * |
| 2819 | * Trivially implemented using the dcache structure |
| 2820 | */ |
| 2821 | |
| 2822 | /** |
| 2823 | * is_subdir - is new dentry a subdirectory of old_dentry |
| 2824 | * @new_dentry: new dentry |
| 2825 | * @old_dentry: old dentry |
| 2826 | * |
| 2827 | * Returns 1 if new_dentry is a subdirectory of the parent (at any depth). |
| 2828 | * Returns 0 otherwise. |
| 2829 | * Caller must ensure that "new_dentry" is pinned before calling is_subdir() |
| 2830 | */ |
| 2831 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2832 | int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2833 | { |
| 2834 | int result; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2835 | unsigned seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2836 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2837 | if (new_dentry == old_dentry) |
| 2838 | return 1; |
| 2839 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2840 | do { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2841 | /* for restarting inner loop in case of seq retry */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2842 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2843 | /* |
| 2844 | * Need rcu_readlock to protect against the d_parent trashing |
| 2845 | * due to d_move |
| 2846 | */ |
| 2847 | rcu_read_lock(); |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2848 | if (d_ancestor(old_dentry, new_dentry)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2849 | result = 1; |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2850 | else |
| 2851 | result = 0; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2852 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2853 | } while (read_seqretry(&rename_lock, seq)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2854 | |
| 2855 | return result; |
| 2856 | } |
| 2857 | |
| 2858 | void d_genocide(struct dentry *root) |
| 2859 | { |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2860 | struct dentry *this_parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2861 | struct list_head *next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2862 | unsigned seq; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2863 | int locked = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2864 | |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2865 | seq = read_seqbegin(&rename_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2866 | again: |
| 2867 | this_parent = root; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2868 | spin_lock(&this_parent->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2869 | repeat: |
| 2870 | next = this_parent->d_subdirs.next; |
| 2871 | resume: |
| 2872 | while (next != &this_parent->d_subdirs) { |
| 2873 | struct list_head *tmp = next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 2874 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2875 | next = tmp->next; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2876 | |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 2877 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
| 2878 | if (d_unhashed(dentry) || !dentry->d_inode) { |
| 2879 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2880 | continue; |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 2881 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2882 | if (!list_empty(&dentry->d_subdirs)) { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2883 | spin_unlock(&this_parent->d_lock); |
| 2884 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2885 | this_parent = dentry; |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2886 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2887 | goto repeat; |
| 2888 | } |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2889 | if (!(dentry->d_flags & DCACHE_GENOCIDE)) { |
| 2890 | dentry->d_flags |= DCACHE_GENOCIDE; |
| 2891 | dentry->d_count--; |
| 2892 | } |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 2893 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2894 | } |
| 2895 | if (this_parent != root) { |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 2896 | struct dentry *child = this_parent; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2897 | if (!(this_parent->d_flags & DCACHE_GENOCIDE)) { |
| 2898 | this_parent->d_flags |= DCACHE_GENOCIDE; |
| 2899 | this_parent->d_count--; |
| 2900 | } |
Linus Torvalds | c826cb7 | 2011-03-15 15:29:21 -0700 | [diff] [blame] | 2901 | this_parent = try_to_ascend(this_parent, locked, seq); |
| 2902 | if (!this_parent) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2903 | goto rename_retry; |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2904 | next = child->d_u.d_child.next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2905 | goto resume; |
| 2906 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 2907 | spin_unlock(&this_parent->d_lock); |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2908 | if (!locked && read_seqretry(&rename_lock, seq)) |
Nick Piggin | 949854d | 2011-01-07 17:49:37 +1100 | [diff] [blame] | 2909 | goto rename_retry; |
Nick Piggin | 58db63d | 2011-01-07 17:49:39 +1100 | [diff] [blame] | 2910 | if (locked) |
| 2911 | write_sequnlock(&rename_lock); |
| 2912 | return; |
| 2913 | |
| 2914 | rename_retry: |
| 2915 | locked = 1; |
| 2916 | write_seqlock(&rename_lock); |
| 2917 | goto again; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2918 | } |
| 2919 | |
| 2920 | /** |
| 2921 | * find_inode_number - check for dentry with name |
| 2922 | * @dir: directory to check |
| 2923 | * @name: Name to find. |
| 2924 | * |
| 2925 | * Check whether a dentry already exists for the given name, |
| 2926 | * and return the inode number if it has an inode. Otherwise |
| 2927 | * 0 is returned. |
| 2928 | * |
| 2929 | * This routine is used to post-process directory listings for |
| 2930 | * filesystems using synthetic inode numbers, and is necessary |
| 2931 | * to keep getcwd() working. |
| 2932 | */ |
| 2933 | |
| 2934 | ino_t find_inode_number(struct dentry *dir, struct qstr *name) |
| 2935 | { |
| 2936 | struct dentry * dentry; |
| 2937 | ino_t ino = 0; |
| 2938 | |
Eric W. Biederman | 3e7e241 | 2006-03-31 02:31:43 -0800 | [diff] [blame] | 2939 | dentry = d_hash_and_lookup(dir, name); |
| 2940 | if (dentry) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2941 | if (dentry->d_inode) |
| 2942 | ino = dentry->d_inode->i_ino; |
| 2943 | dput(dentry); |
| 2944 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2945 | return ino; |
| 2946 | } |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 2947 | EXPORT_SYMBOL(find_inode_number); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2948 | |
| 2949 | static __initdata unsigned long dhash_entries; |
| 2950 | static int __init set_dhash_entries(char *str) |
| 2951 | { |
| 2952 | if (!str) |
| 2953 | return 0; |
| 2954 | dhash_entries = simple_strtoul(str, &str, 0); |
| 2955 | return 1; |
| 2956 | } |
| 2957 | __setup("dhash_entries=", set_dhash_entries); |
| 2958 | |
| 2959 | static void __init dcache_init_early(void) |
| 2960 | { |
| 2961 | int loop; |
| 2962 | |
| 2963 | /* If hashes are distributed across NUMA nodes, defer |
| 2964 | * hash allocation until vmalloc space is available. |
| 2965 | */ |
| 2966 | if (hashdist) |
| 2967 | return; |
| 2968 | |
| 2969 | dentry_hashtable = |
| 2970 | alloc_large_system_hash("Dentry cache", |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 2971 | sizeof(struct hlist_bl_head), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2972 | dhash_entries, |
| 2973 | 13, |
| 2974 | HASH_EARLY, |
| 2975 | &d_hash_shift, |
| 2976 | &d_hash_mask, |
| 2977 | 0); |
| 2978 | |
| 2979 | for (loop = 0; loop < (1 << d_hash_shift); loop++) |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 2980 | INIT_HLIST_BL_HEAD(dentry_hashtable + loop); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2981 | } |
| 2982 | |
Denis Cheng | 74bf17c | 2007-10-16 23:26:30 -0700 | [diff] [blame] | 2983 | static void __init dcache_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2984 | { |
| 2985 | int loop; |
| 2986 | |
| 2987 | /* |
| 2988 | * A constructor could be added for stable state like the lists, |
| 2989 | * but it is probably not worth it because of the cache nature |
| 2990 | * of the dcache. |
| 2991 | */ |
Christoph Lameter | 0a31bd5 | 2007-05-06 14:49:57 -0700 | [diff] [blame] | 2992 | dentry_cache = KMEM_CACHE(dentry, |
| 2993 | SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2994 | |
| 2995 | /* Hash may have been set up in dcache_init_early */ |
| 2996 | if (!hashdist) |
| 2997 | return; |
| 2998 | |
| 2999 | dentry_hashtable = |
| 3000 | alloc_large_system_hash("Dentry cache", |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 3001 | sizeof(struct hlist_bl_head), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3002 | dhash_entries, |
| 3003 | 13, |
| 3004 | 0, |
| 3005 | &d_hash_shift, |
| 3006 | &d_hash_mask, |
| 3007 | 0); |
| 3008 | |
| 3009 | for (loop = 0; loop < (1 << d_hash_shift); loop++) |
Linus Torvalds | b07ad99 | 2011-04-23 22:32:03 -0700 | [diff] [blame] | 3010 | INIT_HLIST_BL_HEAD(dentry_hashtable + loop); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3011 | } |
| 3012 | |
| 3013 | /* SLAB cache for __getname() consumers */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 3014 | struct kmem_cache *names_cachep __read_mostly; |
H Hartley Sweeten | ec4f860 | 2010-01-05 13:45:18 -0700 | [diff] [blame] | 3015 | EXPORT_SYMBOL(names_cachep); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3016 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3017 | EXPORT_SYMBOL(d_genocide); |
| 3018 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3019 | void __init vfs_caches_init_early(void) |
| 3020 | { |
| 3021 | dcache_init_early(); |
| 3022 | inode_init_early(); |
| 3023 | } |
| 3024 | |
| 3025 | void __init vfs_caches_init(unsigned long mempages) |
| 3026 | { |
| 3027 | unsigned long reserve; |
| 3028 | |
| 3029 | /* Base hash sizes on available memory, with a reserve equal to |
| 3030 | 150% of current kernel size */ |
| 3031 | |
| 3032 | reserve = min((mempages - nr_free_pages()) * 3/2, mempages - 1); |
| 3033 | mempages -= reserve; |
| 3034 | |
| 3035 | names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0, |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 3036 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3037 | |
Denis Cheng | 74bf17c | 2007-10-16 23:26:30 -0700 | [diff] [blame] | 3038 | dcache_init(); |
| 3039 | inode_init(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3040 | files_init(mempages); |
Denis Cheng | 74bf17c | 2007-10-16 23:26:30 -0700 | [diff] [blame] | 3041 | mnt_init(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3042 | bdev_cache_init(); |
| 3043 | chrdev_init(); |
| 3044 | } |