diff options
Diffstat (limited to 'fs/inode.c')
| -rw-r--r-- | fs/inode.c | 687 |
1 files changed, 341 insertions, 346 deletions
diff --git a/fs/inode.c b/fs/inode.c index 9910c039f02..33c963d08ab 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -25,6 +25,39 @@ #include <linux/async.h> #include <linux/posix_acl.h> #include <linux/ima.h> +#include <linux/cred.h> +#include "internal.h" + +/* + * inode locking rules. + * + * inode->i_lock protects: + * inode->i_state, inode->i_hash, __iget() + * inode_lru_lock protects: + * inode_lru, inode->i_lru + * inode_sb_list_lock protects: + * sb->s_inodes, inode->i_sb_list + * inode_wb_list_lock protects: + * bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list + * inode_hash_lock protects: + * inode_hashtable, inode->i_hash + * + * Lock ordering: + * + * inode_sb_list_lock + * inode->i_lock + * inode_lru_lock + * + * inode_wb_list_lock + * inode->i_lock + * + * inode_hash_lock + * inode_sb_list_lock + * inode->i_lock + * + * iunique_lock + * inode_hash_lock + */ /* * This is needed for the following functions: @@ -59,6 +92,8 @@ static unsigned int i_hash_mask __read_mostly; static unsigned int i_hash_shift __read_mostly; +static struct hlist_head *inode_hashtable __read_mostly; +static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock); /* * Each inode can be on two separate lists. One is @@ -73,15 +108,10 @@ static unsigned int i_hash_shift __read_mostly; */ static LIST_HEAD(inode_lru); -static struct hlist_head *inode_hashtable __read_mostly; +static DEFINE_SPINLOCK(inode_lru_lock); -/* - * A simple spinlock to protect the list manipulations. - * - * NOTE! You also have to own the lock if you change - * the i_state of an inode while it is in use.. - */ -DEFINE_SPINLOCK(inode_lock); +__cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock); +__cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_wb_list_lock); /* * iprune_sem provides exclusion between the icache shrinking and the @@ -95,6 +125,14 @@ DEFINE_SPINLOCK(inode_lock); static DECLARE_RWSEM(iprune_sem); /* + * Empty aops. Can be used for the cases where the user does not + * define any of the address_space operations. + */ +const struct address_space_operations empty_aops = { +}; +EXPORT_SYMBOL(empty_aops); + +/* * Statistics gathering.. */ struct inodes_stat_t inodes_stat; @@ -136,15 +174,6 @@ int proc_nr_inodes(ctl_table *table, int write, } #endif -static void wake_up_inode(struct inode *inode) -{ - /* - * Prevent speculative execution through spin_unlock(&inode_lock); - */ - smp_mb(); - wake_up_bit(&inode->i_state, __I_NEW); -} - /** * inode_init_always - perform inode structure intialisation * @sb: superblock inode belongs to @@ -155,7 +184,6 @@ static void wake_up_inode(struct inode *inode) */ int inode_init_always(struct super_block *sb, struct inode *inode) { - static const struct address_space_operations empty_aops; static const struct inode_operations empty_iops; static const struct file_operations empty_fops; struct address_space *const mapping = &inode->i_data; @@ -335,7 +363,7 @@ static void init_once(void *foo) } /* - * inode_lock must be held + * inode->i_lock must be held */ void __iget(struct inode *inode) { @@ -353,23 +381,22 @@ EXPORT_SYMBOL(ihold); static void inode_lru_list_add(struct inode *inode) { + spin_lock(&inode_lru_lock); if (list_empty(&inode->i_lru)) { list_add(&inode->i_lru, &inode_lru); inodes_stat.nr_unused++; } + spin_unlock(&inode_lru_lock); } static void inode_lru_list_del(struct inode *inode) { + spin_lock(&inode_lru_lock); if (!list_empty(&inode->i_lru)) { list_del_init(&inode->i_lru); inodes_stat.nr_unused--; } -} - -static inline void __inode_sb_list_add(struct inode *inode) -{ - list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); + spin_unlock(&inode_lru_lock); } /** @@ -378,15 +405,17 @@ static inline void __inode_sb_list_add(struct inode *inode) */ void inode_sb_list_add(struct inode *inode) { - spin_lock(&inode_lock); - __inode_sb_list_add(inode); - spin_unlock(&inode_lock); + spin_lock(&inode_sb_list_lock); + list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); + spin_unlock(&inode_sb_list_lock); } EXPORT_SYMBOL_GPL(inode_sb_list_add); -static inline void __inode_sb_list_del(struct inode *inode) +static inline void inode_sb_list_del(struct inode *inode) { + spin_lock(&inode_sb_list_lock); list_del_init(&inode->i_sb_list); + spin_unlock(&inode_sb_list_lock); } static unsigned long hash(struct super_block *sb, unsigned long hashval) @@ -411,24 +440,15 @@ void __insert_inode_hash(struct inode *inode, unsigned long hashval) { struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval); - spin_lock(&inode_lock); + spin_lock(&inode_hash_lock); + spin_lock(&inode->i_lock); hlist_add_head(&inode->i_hash, b); - spin_unlock(&inode_lock); + spin_unlock(&inode->i_lock); + spin_unlock(&inode_hash_lock); } EXPORT_SYMBOL(__insert_inode_hash); /** - * __remove_inode_hash - remove an inode from the hash - * @inode: inode to unhash - * - * Remove an inode from the superblock. - */ -static void __remove_inode_hash(struct inode *inode) -{ - hlist_del_init(&inode->i_hash); -} - -/** * remove_inode_hash - remove an inode from the hash * @inode: inode to unhash * @@ -436,9 +456,11 @@ static void __remove_inode_hash(struct inode *inode) */ void remove_inode_hash(struct inode *inode) { - spin_lock(&inode_lock); + spin_lock(&inode_hash_lock); + spin_lock(&inode->i_lock); hlist_del_init(&inode->i_hash); - spin_unlock(&inode_lock); + spin_unlock(&inode->i_lock); + spin_unlock(&inode_hash_lock); } EXPORT_SYMBOL(remove_inode_hash); @@ -455,10 +477,29 @@ void end_writeback(struct inode *inode) } EXPORT_SYMBOL(end_writeback); +/* + * Free the inode passed in, removing it from the lists it is still connected + * to. We remove any pages still attached to the inode and wait for any IO that + * is still in progress before finally destroying the inode. + * + * An inode must already be marked I_FREEING so that we avoid the inode being + * moved back onto lists if we race with other code that manipulates the lists + * (e.g. writeback_single_inode). The caller is responsible for setting this. + * + * An inode must already be removed from the LRU list before being evicted from + * the cache. This should occur atomically with setting the I_FREEING state + * flag, so no inodes here should ever be on the LRU when being evicted. + */ static void evict(struct inode *inode) { const struct super_operations *op = inode->i_sb->s_op; + BUG_ON(!(inode->i_state & I_FREEING)); + BUG_ON(!list_empty(&inode->i_lru)); + + inode_wb_list_del(inode); + inode_sb_list_del(inode); + if (op->evict_inode) { op->evict_inode(inode); } else { @@ -470,6 +511,15 @@ static void evict(struct inode *inode) bd_forget(inode); if (S_ISCHR(inode->i_mode) && inode->i_cdev) cd_forget(inode); + + remove_inode_hash(inode); + + spin_lock(&inode->i_lock); + wake_up_bit(&inode->i_state, __I_NEW); + BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); + spin_unlock(&inode->i_lock); + + destroy_inode(inode); } /* @@ -488,14 +538,6 @@ static void dispose_list(struct list_head *head) list_del_init(&inode->i_lru); evict(inode); - - spin_lock(&inode_lock); - __remove_inode_hash(inode); - __inode_sb_list_del(inode); - spin_unlock(&inode_lock); - - wake_up_inode(inode); - destroy_inode(inode); } } @@ -513,25 +555,23 @@ void evict_inodes(struct super_block *sb) struct inode *inode, *next; LIST_HEAD(dispose); - spin_lock(&inode_lock); + spin_lock(&inode_sb_list_lock); list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { if (atomic_read(&inode->i_count)) continue; - if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) + + spin_lock(&inode->i_lock); + if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { + spin_unlock(&inode->i_lock); continue; + } inode->i_state |= I_FREEING; - - /* - * Move the inode off the IO lists and LRU once I_FREEING is - * set so that it won't get moved back on there if it is dirty. - */ - list_move(&inode->i_lru, &dispose); - list_del_init(&inode->i_wb_list); - if (!(inode->i_state & (I_DIRTY | I_SYNC))) - inodes_stat.nr_unused--; + inode_lru_list_del(inode); + spin_unlock(&inode->i_lock); + list_add(&inode->i_lru, &dispose); } - spin_unlock(&inode_lock); + spin_unlock(&inode_sb_list_lock); dispose_list(&dispose); @@ -560,31 +600,30 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty) struct inode *inode, *next; LIST_HEAD(dispose); - spin_lock(&inode_lock); + spin_lock(&inode_sb_list_lock); list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { - if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) + spin_lock(&inode->i_lock); + if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { + spin_unlock(&inode->i_lock); continue; + } if (inode->i_state & I_DIRTY && !kill_dirty) { + spin_unlock(&inode->i_lock); busy = 1; continue; } if (atomic_read(&inode->i_count)) { + spin_unlock(&inode->i_lock); busy = 1; continue; } inode->i_state |= I_FREEING; - - /* - * Move the inode off the IO lists and LRU once I_FREEING is - * set so that it won't get moved back on there if it is dirty. - */ - list_move(&inode->i_lru, &dispose); - list_del_init(&inode->i_wb_list); - if (!(inode->i_state & (I_DIRTY | I_SYNC))) - inodes_stat.nr_unused--; + inode_lru_list_del(inode); + spin_unlock(&inode->i_lock); + list_add(&inode->i_lru, &dispose); } - spin_unlock(&inode_lock); + spin_unlock(&inode_sb_list_lock); dispose_list(&dispose); @@ -606,7 +645,7 @@ static int can_unuse(struct inode *inode) /* * Scan `goal' inodes on the unused list for freeable ones. They are moved to a - * temporary list and then are freed outside inode_lock by dispose_list(). + * temporary list and then are freed outside inode_lru_lock by dispose_list(). * * Any inodes which are pinned purely because of attached pagecache have their * pagecache removed. If the inode has metadata buffers attached to @@ -627,7 +666,7 @@ static void prune_icache(int nr_to_scan) unsigned long reap = 0; down_read(&iprune_sem); - spin_lock(&inode_lock); + spin_lock(&inode_lru_lock); for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { struct inode *inode; @@ -637,53 +676,67 @@ static void prune_icache(int nr_to_scan) inode = list_entry(inode_lru.prev, struct inode, i_lru); /* + * we are inverting the inode_lru_lock/inode->i_lock here, + * so use a trylock. If we fail to get the lock, just move the + * inode to the back of the list so we don't spin on it. + */ + if (!spin_trylock(&inode->i_lock)) { + list_move(&inode->i_lru, &inode_lru); + continue; + } + + /* * Referenced or dirty inodes are still in use. Give them * another pass through the LRU as we canot reclaim them now. */ if (atomic_read(&inode->i_count) || (inode->i_state & ~I_REFERENCED)) { list_del_init(&inode->i_lru); + spin_unlock(&inode->i_lock); inodes_stat.nr_unused--; continue; } /* recently referenced inodes get one more pass */ if (inode->i_state & I_REFERENCED) { - list_move(&inode->i_lru, &inode_lru); inode->i_state &= ~I_REFERENCED; + list_move(&inode->i_lru, &inode_lru); + spin_unlock(&inode->i_lock); continue; } if (inode_has_buffers(inode) || inode->i_data.nrpages) { __iget(inode); - spin_unlock(&inode_lock); + spin_unlock(&inode->i_lock); + spin_unlock(&inode_lru_lock); if (remove_inode_buffers(inode)) reap += invalidate_mapping_pages(&inode->i_data, 0, -1); iput(inode); - spin_lock(&inode_lock); + spin_lock(&inode_lru_lock); if (inode != list_entry(inode_lru.next, struct inode, i_lru)) continue; /* wrong inode or list_empty */ - if (!can_unuse(inode)) + /* avoid lock inversions with trylock */ + if (!spin_trylock(&inode->i_lock)) + continue; + if (!can_unuse(inode)) { + spin_unlock(&inode->i_lock); continue; + } } WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; + spin_unlock(&inode->i_lock); - /* - * Move the inode off the IO lists and LRU once I_FREEING is - * set so that it won't get moved back on there if it is dirty. - */ list_move(&inode->i_lru, &freeable); - list_del_init(&inode->i_wb_list); inodes_stat.nr_unused--; } if (current_is_kswapd()) __count_vm_events(KSWAPD_INODESTEAL, reap); else __count_vm_events(PGINODESTEAL, reap); - spin_unlock(&inode_lock); + spin_unlock(&inode_lru_lock); dispose_list(&freeable); up_read(&iprune_sem); @@ -732,15 +785,21 @@ static struct inode *find_inode(struct super_block *sb, repeat: hlist_for_each_entry(inode, node, head, i_hash) { - if (inode->i_sb != sb) + spin_lock(&inode->i_lock); + if (inode->i_sb != sb) { + spin_unlock(&inode->i_lock); continue; - if (!test(inode, data)) + } + if (!test(inode, data)) { + spin_unlock(&inode->i_lock); continue; + } if (inode->i_state & (I_FREEING|I_WILL_FREE)) { __wait_on_freeing_inode(inode); goto repeat; } __iget(inode); + spin_unlock(&inode->i_lock); return inode; } return NULL; @@ -758,15 +817,21 @@ static struct inode *find_inode_fast(struct super_block *sb, repeat: hlist_for_each_entry(inode, node, head, i_hash) { - if (inode->i_ino != ino) + spin_lock(&inode->i_lock); + if (inode->i_ino != ino) { + spin_unlock(&inode->i_lock); continue; - if (inode->i_sb != sb) + } + if (inode->i_sb != sb) { + spin_unlock(&inode->i_lock); continue; + } if (inode->i_state & (I_FREEING|I_WILL_FREE)) { __wait_on_freeing_inode(inode); goto repeat; } __iget(inode); + spin_unlock(&inode->i_lock); return inode; } return NULL; @@ -826,19 +891,26 @@ struct inode *new_inode(struct super_block *sb) { struct inode *inode; - spin_lock_prefetch(&inode_lock); + spin_lock_prefetch(&inode_sb_list_lock); inode = alloc_inode(sb); if (inode) { - spin_lock(&inode_lock); - __inode_sb_list_add(inode); + spin_lock(&inode->i_lock); inode->i_state = 0; - spin_unlock(&inode_lock); + spin_unlock(&inode->i_lock); + inode_sb_list_add(inode); } return inode; } EXPORT_SYMBOL(new_inode); +/** + * unlock_new_inode - clear the I_NEW state and wake up any waiters + * @inode: new inode to unlock + * + * Called when the inode is fully initialised to clear the new state of the + * inode and wake up anyone waiting for the inode to finish initialisation. + */ void unlock_new_inode(struct inode *inode) { #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -858,51 +930,67 @@ void unlock_new_inode(struct inode *inode) } } #endif - /* - * This is special! We do not need the spinlock when clearing I_NEW, - * because we're guaranteed that nobody else tries to do anything about - * the state of the inode when it is locked, as we just created it (so - * there can be no old holders that haven't tested I_NEW). - * However we must emit the memory barrier so that other CPUs reliably - * see the clearing of I_NEW after the other inode initialisation has - * completed. - */ - smp_mb(); + spin_lock(&inode->i_lock); WARN_ON(!(inode->i_state & I_NEW)); inode->i_state &= ~I_NEW; - wake_up_inode(inode); + wake_up_bit(&inode->i_state, __I_NEW); + spin_unlock(&inode->i_lock); } EXPORT_SYMBOL(unlock_new_inode); -/* - * This is called without the inode lock held.. Be careful. +/** + * iget5_locked - obtain an inode from a mounted file system + * @sb: super block of file system + * @hashval: hash value (usually inode number) to get + * @test: callback used for comparisons between inodes + * @set: callback used to initialize a new struct inode + * @data: opaque data pointer to pass to @test and @set * - * We no longer cache the sb_flags in i_flags - see fs.h - * -- rmk@arm.uk.linux.org + * Search for the inode specified by @hashval and @data in the inode cache, + * and if present it is return it with an increased reference count. This is + * a generalized version of iget_locked() for file systems where the inode + * number is not sufficient for unique identification of an inode. + * + * If the inode is not in cache, allocate a new inode and return it locked, + * hashed, and with the I_NEW flag set. The file system gets to fill it in + * before unlocking it via unlock_new_inode(). + * + * Note both @test and @set are called with the inode_hash_lock held, so can't + * sleep. */ -static struct inode *get_new_inode(struct super_block *sb, - struct hlist_head *head, - int (*test)(struct inode *, void *), - int (*set)(struct inode *, void *), - void *data) +struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, + int (*test)(struct inode *, void *), + int (*set)(struct inode *, void *), void *data) { + struct hlist_head *head = inode_hashtable + hash(sb, hashval); struct inode *inode; + spin_lock(&inode_hash_lock); + inode = find_inode(sb, head, test, data); + spin_unlock(&inode_hash_lock); + + if (inode) { + wait_on_inode(inode); + return inode; + } + inode = alloc_inode(sb); if (inode) { struct inode *old; - spin_lock(&inode_lock); + spin_lock(&inode_hash_lock); /* We released the lock, so.. */ old = find_inode(sb, head, test, data); if (!old) { if (set(inode, data)) goto set_failed; - hlist_add_head(&inode->i_hash, head); - __inode_sb_list_add(inode); + spin_lock(&inode->i_lock); inode->i_state = I_NEW; - spin_unlock(&inode_lock); + hlist_add_head(&inode->i_hash, head); + spin_unlock(&inode->i_lock); + inode_sb_list_add(inode); + spin_unlock(&inode_hash_lock); /* Return the locked inode with I_NEW set, the * caller is responsible for filling in the contents @@ -915,7 +1003,7 @@ static struct inode *get_new_inode(struct super_block *sb, * us. Use the old inode instead of the one we just * allocated. */ - spin_unlock(&inode_lock); + spin_unlock(&inode_hash_lock); destroy_inode(inode); inode = old; wait_on_inode(inode); @@ -923,33 +1011,53 @@ static struct inode *get_new_inode(struct super_block *sb, return inode; set_failed: - spin_unlock(&inode_lock); + spin_unlock(&inode_hash_lock); destroy_inode(inode); return NULL; } +EXPORT_SYMBOL(iget5_locked); -/* - * get_new_inode_fast is the fast path version of get_new_inode, see the - * comment at iget_locked for details. +/** + * iget_locked - obtain an inode from a mounted file system + * @sb: super block of file system + * @ino: inode number to get + * + * Search for the inode specified by @ino in the inode cache and if present + * return it with an increased reference count. This is for file systems + * where the inode number is sufficient for unique identification of an inode. + * + * If the inode is not in cache, allocate a new inode and return it locked, + * hashed, and with the I_NEW flag set. The file system gets to fill it in + * before unlocking it via unlock_new_inode(). */ -static struct inode *get_new_inode_fast(struct super_block *sb, - struct hlist_head *head, unsigned long ino) +struct inode *iget_locked(struct super_block *sb, unsigned long ino) { + struct hlist_head *head = inode_hashtable + hash(sb, ino); struct inode *inode; + spin_lock(&inode_hash_lock); + inode = find_inode_fast(sb, head, ino); + spin_unlock(&inode_hash_lock); + if (inode) { + wait_on_inode(inode); + return inode; + } + inode = alloc_inode(sb); if (inode) { struct inode *old; - spin_lock(&inode_lock); + spin_lock(&inode_hash_lock); /* We released the lock, so.. */ old = find_inode_fast(sb, head, ino); if (!old) { inode->i_ino = ino; - hlist_add_head(&inode->i_hash, head); - __inode_sb_list_add(inode); + spin_lock(&inode->i_lock); inode->i_state = I_NEW; - spin_unlock(&inode_lock); + hlist_add_head(&inode->i_hash, head); + spin_unlock(&inode->i_lock); + inode_sb_list_add(inode); + spin_unlock(&inode_hash_lock); /* Return the locked inode with I_NEW set, the * caller is responsible for filling in the contents @@ -962,13 +1070,14 @@ static struct inode *get_new_inode_fast(struct super_block *sb, * us. Use the old inode instead of the one we just * allocated. */ - spin_unlock(&inode_lock); + spin_unlock(&inode_hash_lock); destroy_inode(inode); inode = old; wait_on_inode(inode); } return inode; } +EXPORT_SYMBOL(iget_locked); /* * search the inode cache for a matching inode number. @@ -983,10 +1092,14 @@ static int test_inode_iunique(struct super_block *sb, unsigned long ino) struct hlist_node *node; struct inode *inode; + spin_lock(&inode_hash_lock); hlist_for_each_entry(inode, node, b, i_hash) { - if (inode->i_ino == ino && inode->i_sb == sb) + if (inode->i_ino == ino && inode->i_sb == sb) { + spin_unlock(&inode_hash_lock); return 0; + } } + spin_unlock(&inode_hash_lock); return 1; } @@ -1016,7 +1129,6 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved) static unsigned int counter; ino_t res; - spin_lock(&inode_lock); spin_lock(&iunique_lock); do { if (counter <= max_reserved) @@ -1024,7 +1136,6 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved) res = counter++; } while (!test_inode_iunique(sb, res)); spin_unlock(&iunique_lock); - spin_unlock(&inode_lock); return res; } @@ -1032,116 +1143,50 @@ EXPORT_SYMBOL(iunique); struct inode *igrab(struct inode *inode) { - spin_lock(&inode_lock); - if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) + spin_lock(&inode->i_lock); + if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) { __iget(inode); - else + spin_unlock(&inode->i_lock); + } else { + spin_unlock(&inode->i_lock); /* * Handle the case where s_op->clear_inode is not been * called yet, and somebody is calling igrab * while the inode is getting freed. */ inode = NULL; - spin_unlock(&inode_lock); + } return inode; } EXPORT_SYMBOL(igrab); /** - * ifind - internal function, you want ilookup5() or iget5(). - * @sb: super block of file system to search - * @head: the head of the list to search - * @test: callback used for comparisons between inodes - * @data: opaque data pointer to pass to @test - * @wait: if true wait for the inode to be unlocked, if false do not - * - * ifind() searches for the inode specified by @data in the inode - * cache. This is a generalized version of ifind_fast() for file systems where - * the inode number is not sufficient for unique identification of an inode. - * - * If the inode is in the cache, the inode is returned with an incremented - * reference count. - * - * Otherwise NULL is returned. - * - * Note, @test is called with the inode_lock held, so can't sleep. - */ -static struct inode *ifind(struct super_block *sb, - struct hlist_head *head, int (*test)(struct inode *, void *), - void *data, const int wait) -{ - struct inode *inode; - - spin_lock(&inode_lock); - inode = find_inode(sb, head, test, data); - if (inode) { - spin_unlock(&inode_lock); - if (likely(wait)) - wait_on_inode(inode); - return inode; - } - spin_unlock(&inode_lock); - return NULL; -} - -/** - * ifind_fast - internal function, you want ilookup() or iget(). - * @sb: super block of file system to search - * @head: head of the list to search - * @ino: inode number to search for - * - * ifind_fast() searches for the inode @ino in the inode cache. This is for - * file systems where the inode number is sufficient for unique identification - * of an inode. - * - * If the inode is in the cache, the inode is returned with an incremented - * reference count. - * - * Otherwise NULL is returned. - */ -static struct inode *ifind_fast(struct super_block *sb, - struct hlist_head *head, unsigned long ino) -{ - struct inode *inode; - - spin_lock(&inode_lock); - inode = find_inode_fast(sb, head, ino); - if (inode) { - spin_unlock(&inode_lock); - wait_on_inode(inode); - return inode; - } - spin_unlock(&inode_lock); - return NULL; -} - -/** * ilookup5_nowait - search for an inode in the inode cache * @sb: super block of file system to search * @hashval: hash value (usually inode number) to search for * @test: callback used for comparisons between inodes * @data: opaque data pointer to pass to @test * - * ilookup5() uses ifind() to search for the inode specified by @hashval and - * @data in the inode cache. This is a generalized version of ilookup() for - * file systems where the inode number is not sufficient for unique - * identification of an inode. - * + * Search for the inode specified by @hashval and @data in the inode cache. * If the inode is in the cache, the inode is returned with an incremented - * reference count. Note, the inode lock is not waited upon so you have to be - * very careful what you do with the returned inode. You probably should be - * using ilookup5() instead. + * reference count. * - * Otherwise NULL is returned. + * Note: I_NEW is not waited upon so you have to be very careful what you do + * with the returned inode. You probably should be using ilookup5() instead. * - * Note, @test is called with the inode_lock held, so can't sleep. + * Note2: @test is called with the inode_hash_lock held, so can't sleep. */ struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, int (*test)(struct inode *, void *), void *data) { struct hlist_head *head = inode_hashtable + hash(sb, hashval); + struct inode *inode; + + spin_lock(&inode_hash_lock); + inode = find_inode(sb, head, test, data); + spin_unlock(&inode_hash_lock); - return ifind(sb, head, test, data, 0); + return inode; } EXPORT_SYMBOL(ilookup5_nowait); @@ -1152,24 +1197,24 @@ EXPORT_SYMBOL(ilookup5_nowait); * @test: callback used for comparisons between inodes * @data: opaque data pointer to pass to @test * - * ilookup5() uses ifind() to search for the inode specified by @hashval and - * @data in the inode cache. This is a generalized version of ilookup() for - * file systems where the inode number is not sufficient for unique - * identification of an inode. - * - * If the inode is in the cache, the inode lock is waited upon and the inode is + * Search for the inode specified by @hashval and @data in the inode cache, + * and if the inode is in the cache, return the inode with an incremented + * reference count. Waits on I_NEW before returning the inode. * returned with an incremented reference count. * - * Otherwise NULL is returned. + * This is a generalized version of ilookup() for file systems where the + * inode number is not sufficient for unique identification of an inode. * - * Note, @test is called with the inode_lock held, so can't sleep. + * Note: @test is called with the inode_hash_lock held, so can't sleep. */ struct inode *ilookup5(struct super_block *sb, unsigned long hashval, int (*test)(struct inode *, void *), void *data) { - struct hlist_head *head = inode_hashtable + hash(sb, hashval); + struct inode *inode = ilookup5_nowait(sb, hashval, test, data); - return ifind(sb, head, test, data, 1); + if (inode) + wait_on_inode(inode); + return inode; } EXPORT_SYMBOL(ilookup5); @@ -1178,91 +1223,23 @@ EXPORT_SYMBOL(ilookup5); * @sb: super block of file system to search * @ino: inode number to search for * - * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache. - * This is for file systems where the inode number is sufficient for unique - * identification of an inode. - * - * If the inode is in the cache, the inode is returned with an incremented - * reference count. - * - * Otherwise NULL is returned. + * Search for the inode @ino in the inode cache, and if the inode is in the + * cache, the inode is returned with an incremented reference count. */ struct inode *ilookup(struct super_block *sb, unsigned long ino) { struct hlist_head *head = inode_hashtable + hash(sb, ino); - - return ifind_fast(sb, head, ino); -} -EXPORT_SYMBOL(ilookup); - -/** - * iget5_locked - obtain an inode from a mounted file system - * @sb: super block of file system - * @hashval: hash value (usually inode number) to get - * @test: callback used for comparisons between inodes - * @set: callback used to initialize a new struct inode - * @data: opaque data pointer to pass to @test and @set - * - * iget5_locked() uses ifind() to search for the inode specified by @hashval - * and @data in the inode cache and if present it is returned with an increased - * reference count. This is a generalized version of iget_locked() for file - * systems where the inode number is not sufficient for unique identification - * of an inode. - * - * If the inode is not in cache, get_new_inode() is called to allocate a new - * inode and this is returned locked, hashed, and with the I_NEW flag set. The - * file system gets to fill it in before unlocking it via unlock_new_inode(). - * - * Note both @test and @set are called with the inode_lock held, so can't sleep. - */ -struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, - int (*test)(struct inode *, void *), - int (*set)(struct inode *, void *), void *data) -{ - struct hlist_head *head = inode_hashtable + hash(sb, hashval); struct inode *inode; - inode = ifind(sb, head, test, data, 1); - if (inode) - return inode; - /* - * get_new_inode() will do the right thing, re-trying the search - * in case it had to block at any point. - */ - return get_new_inode(sb, head, test, set, data); -} -EXPORT_SYMBOL(iget5_locked); - -/** - * iget_locked - obtain an inode from a mounted file system - * @sb: super block of file system - * @ino: inode number to get - * - * iget_locked() uses ifind_fast() to search for the inode specified by @ino in - * the inode cache and if present it is returned with an increased reference - * count. This is for file systems where the inode number is sufficient for - * unique identification of an inode. - * - * If the inode is not in cache, get_new_inode_fast() is called to allocate a - * new inode and this is returned locked, hashed, and with the I_NEW flag set. - * The file system gets to fill it in before unlocking it via - * unlock_new_inode(). - */ -struct inode *iget_locked(struct super_block *sb, unsigned long ino) -{ - struct hlist_head *head = inode_hashtable + hash(sb, ino); - struct inode *inode; + spin_lock(&inode_hash_lock); + inode = find_inode_fast(sb, head, ino); + spin_unlock(&inode_hash_lock); - inode = ifind_fast(sb, head, ino); if (inode) - return inode; - /* - * get_new_inode_fast() will do the right thing, re-trying the search - * in case it had to block at any point. - */ - return get_new_inode_fast(sb, head, ino); + wait_on_inode(inode); + return inode; } -EXPORT_SYMBOL(iget_locked); +EXPORT_SYMBOL(ilookup); int insert_inode_locked(struct inode *inode) { @@ -1270,27 +1247,33 @@ int insert_inode_locked(struct inode *inode) ino_t ino = inode->i_ino; struct hlist_head *head = inode_hashtable + hash(sb, ino); - inode->i_state |= I_NEW; while (1) { struct hlist_node *node; struct inode *old = NULL; - spin_lock(&inode_lock); + spin_lock(&inode_hash_lock); hlist_for_each_entry(old, node, head, i_hash) { if (old->i_ino != ino) continue; if (old->i_sb != sb) continue; - if (old->i_state & (I_FREEING|I_WILL_FREE)) + spin_lock(&old->i_lock); + if (old->i_state & (I_FREEING|I_WILL_FREE)) { + spin_unlock(&old->i_lock); continue; + } break; } if (likely(!node)) { + spin_lock(&inode->i_lock); + inode->i_state |= I_NEW; hlist_add_head(&inode->i_hash, head); - spin_unlock(&inode_lock); + spin_unlock(&inode->i_lock); + spin_unlock(&inode_hash_lock); return 0; } __iget(old); - spin_unlock(&inode_lock); + spin_unlock(&old->i_lock); + spin_unlock(&inode_hash_lock); wait_on_inode(old); if (unlikely(!inode_unhashed(old))) { iput(old); @@ -1307,29 +1290,34 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval, struct super_block *sb = inode->i_sb; struct hlist_head *head = inode_hashtable + hash(sb, hashval); - inode->i_state |= I_NEW; - while (1) { struct hlist_node *node; struct inode *old = NULL; - spin_lock(&inode_lock); + spin_lock(&inode_hash_lock); hlist_for_each_entry(old, node, head, i_hash) { if (old->i_sb != sb) continue; if (!test(old, data)) continue; - if (old->i_state & (I_FREEING|I_WILL_FREE)) + spin_lock(&old->i_lock); + if (old->i_state & (I_FREEING|I_WILL_FREE)) { + spin_unlock(&old->i_lock); continue; + } break; } if (likely(!node)) { + spin_lock(&inode->i_lock); + inode->i_state |= I_NEW; hlist_add_head(&inode->i_hash, head); - spin_unlock(&inode_lock); + spin_unlock(&inode->i_lock); + spin_unlock(&inode_hash_lock); return 0; } __iget(old); - spin_unlock(&inode_lock); + spin_unlock(&old->i_lock); + spin_unlock(&inode_hash_lock); wait_on_inode(old); if (unlikely(!inode_unhashed(old))) { iput(old); @@ -1374,47 +1362,35 @@ static void iput_final(struct inode *inode) const struct super_operations *op = inode->i_sb->s_op; int drop; + WARN_ON(inode->i_state & I_NEW); + if (op && op->drop_inode) drop = op->drop_inode(inode); else drop = generic_drop_inode(inode); + if (!drop && (sb->s_flags & MS_ACTIVE)) { + inode->i_state |= I_REFERENCED; + if (!(inode->i_state & (I_DIRTY|I_SYNC))) + inode_lru_list_add(inode); + spin_unlock(&inode->i_lock); + return; + } + if (!drop) { - if (sb->s_flags & MS_ACTIVE) { - inode->i_state |= I_REFERENCED; - if (!(inode->i_state & (I_DIRTY|I_SYNC))) { - inode_lru_list_add(inode); - } - spin_unlock(&inode_lock); - return; - } - WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_WILL_FREE; - spin_unlock(&inode_lock); + spin_unlock(&inode->i_lock); write_inode_now(inode, 1); - spin_lock(&inode_lock); + spin_lock(&inode->i_lock); WARN_ON(inode->i_state & I_NEW); inode->i_state &= ~I_WILL_FREE; - __remove_inode_hash(inode); } - WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; - - /* - * Move the inode off the IO lists and LRU once I_FREEING is - * set so that it won't get moved back on there if it is dirty. - */ inode_lru_list_del(inode); - list_del_init(&inode->i_wb_list); + spin_unlock(&inode->i_lock); - __inode_sb_list_del(inode); - spin_unlock(&inode_lock); evict(inode); - remove_inode_hash(inode); - wake_up_inode(inode); - BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); - destroy_inode(inode); } /** @@ -1431,7 +1407,7 @@ void iput(struct inode *inode) if (inode) { BUG_ON(inode->i_state & I_CLEAR); - if (atomic_dec_and_lock(&inode->i_count, &inode_lock)) + if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) iput_final(inode); } } @@ -1610,9 +1586,8 @@ EXPORT_SYMBOL(inode_wait); * to recheck inode state. * * It doesn't matter if I_NEW is not set initially, a call to - * wake_up_inode() after removing from the hash list will DTRT. - * - * This is called with inode_lock held. + * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list + * will DTRT. */ static void __wait_on_freeing_inode(struct inode *inode) { @@ -1620,10 +1595,11 @@ static void __wait_on_freeing_inode(struct inode *inode) DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); wq = bit_waitqueue(&inode->i_state, __I_NEW); prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); - spin_unlock(&inode_lock); + spin_unlock(&inode->i_lock); + spin_unlock(&inode_hash_lock); schedule(); finish_wait(wq, &wait.wait); - spin_lock(&inode_lock); + spin_lock(&inode_hash_lock); } static __initdata unsigned long ihash_entries; @@ -1715,7 +1691,7 @@ void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) EXPORT_SYMBOL(init_special_inode); /** - * Init uid,gid,mode for new inode according to posix standards + * inode_init_owner - Init uid,gid,mode for new inode according to posix standards * @inode: New inode * @dir: Directory inode * @mode: mode of the new inode @@ -1733,3 +1709,22 @@ void inode_init_owner(struct inode *inode, const struct inode *dir, inode->i_mode = mode; } EXPORT_SYMBOL(inode_init_owner); + +/** + * inode_owner_or_capable - check current task permissions to inode + * @inode: inode being checked + * + * Return true if current either has CAP_FOWNER to the inode, or + * owns the file. + */ +bool inode_owner_or_capable(const struct inode *inode) +{ + struct user_namespace *ns = inode_userns(inode); + + if (current_user_ns() == ns && current_fsuid() == inode->i_uid) + return true; + if (ns_capable(ns, CAP_FOWNER)) + return true; + return false; +} +EXPORT_SYMBOL(inode_owner_or_capable); |