diff options
Diffstat (limited to 'fs/dcache.c')
| -rw-r--r-- | fs/dcache.c | 106 |
1 files changed, 58 insertions, 48 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index 9791b1e7eee..16a53cc2cc0 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -243,6 +243,7 @@ static void dentry_lru_add(struct dentry *dentry) static void __dentry_lru_del(struct dentry *dentry) { list_del_init(&dentry->d_lru); + dentry->d_flags &= ~DCACHE_SHRINK_LIST; dentry->d_sb->s_nr_dentry_unused--; dentry_stat.nr_unused--; } @@ -276,15 +277,15 @@ static void dentry_lru_prune(struct dentry *dentry) } } -static void dentry_lru_move_tail(struct dentry *dentry) +static void dentry_lru_move_list(struct dentry *dentry, struct list_head *list) { spin_lock(&dcache_lru_lock); if (list_empty(&dentry->d_lru)) { - list_add_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); + list_add_tail(&dentry->d_lru, list); dentry->d_sb->s_nr_dentry_unused++; dentry_stat.nr_unused++; } else { - list_move_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); + list_move_tail(&dentry->d_lru, list); } spin_unlock(&dcache_lru_lock); } @@ -770,14 +771,18 @@ static void shrink_dentry_list(struct list_head *list) } /** - * __shrink_dcache_sb - shrink the dentry LRU on a given superblock - * @sb: superblock to shrink dentry LRU. - * @count: number of entries to prune - * @flags: flags to control the dentry processing + * prune_dcache_sb - shrink the dcache + * @sb: superblock + * @count: number of entries to try to free + * + * Attempt to shrink the superblock dcache LRU by @count entries. This is + * done when we need more memory an called from the superblock shrinker + * function. * - * If flags contains DCACHE_REFERENCED reference dentries will not be pruned. + * This function may fail to free any resources if all the dentries are in + * use. */ -static void __shrink_dcache_sb(struct super_block *sb, int count, int flags) +void prune_dcache_sb(struct super_block *sb, int count) { struct dentry *dentry; LIST_HEAD(referenced); @@ -796,18 +801,13 @@ relock: goto relock; } - /* - * If we are honouring the DCACHE_REFERENCED flag and the - * dentry has this flag set, don't free it. Clear the flag - * and put it back on the LRU. - */ - if (flags & DCACHE_REFERENCED && - dentry->d_flags & DCACHE_REFERENCED) { + if (dentry->d_flags & DCACHE_REFERENCED) { dentry->d_flags &= ~DCACHE_REFERENCED; list_move(&dentry->d_lru, &referenced); spin_unlock(&dentry->d_lock); } else { list_move_tail(&dentry->d_lru, &tmp); + dentry->d_flags |= DCACHE_SHRINK_LIST; spin_unlock(&dentry->d_lock); if (!--count) break; @@ -822,23 +822,6 @@ relock: } /** - * prune_dcache_sb - shrink the dcache - * @sb: superblock - * @nr_to_scan: number of entries to try to free - * - * Attempt to shrink the superblock dcache LRU by @nr_to_scan entries. This is - * done when we need more memory an called from the superblock shrinker - * function. - * - * This function may fail to free any resources if all the dentries are in - * use. - */ -void prune_dcache_sb(struct super_block *sb, int nr_to_scan) -{ - __shrink_dcache_sb(sb, nr_to_scan, DCACHE_REFERENCED); -} - -/** * shrink_dcache_sb - shrink dcache for a superblock * @sb: superblock * @@ -1092,7 +1075,7 @@ EXPORT_SYMBOL(have_submounts); * drop the lock and return early due to latency * constraints. */ -static int select_parent(struct dentry * parent) +static int select_parent(struct dentry *parent, struct list_head *dispose) { struct dentry *this_parent; struct list_head *next; @@ -1114,17 +1097,21 @@ resume: spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); - /* - * move only zero ref count dentries to the end - * of the unused list for prune_dcache + /* + * move only zero ref count dentries to the dispose list. + * + * Those which are presently on the shrink list, being processed + * by shrink_dentry_list(), shouldn't be moved. Otherwise the + * loop in shrink_dcache_parent() might not make any progress + * and loop forever. */ - if (!dentry->d_count) { - dentry_lru_move_tail(dentry); - found++; - } else { + if (dentry->d_count) { dentry_lru_del(dentry); + } else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) { + dentry_lru_move_list(dentry, dispose); + dentry->d_flags |= DCACHE_SHRINK_LIST; + found++; } - /* * We can return to the caller if we have found some (this * ensures forward progress). We'll be coming back to find @@ -1181,14 +1168,13 @@ rename_retry: * * Prune the dcache to remove unused children of the parent dentry. */ - void shrink_dcache_parent(struct dentry * parent) { - struct super_block *sb = parent->d_sb; + LIST_HEAD(dispose); int found; - while ((found = select_parent(parent)) != 0) - __shrink_dcache_sb(sb, found, 0); + while ((found = select_parent(parent, &dispose)) != 0) + shrink_dentry_list(&dispose); } EXPORT_SYMBOL(shrink_dcache_parent); @@ -1461,6 +1447,23 @@ struct dentry * d_alloc_root(struct inode * root_inode) } EXPORT_SYMBOL(d_alloc_root); +struct dentry *d_make_root(struct inode *root_inode) +{ + struct dentry *res = NULL; + + if (root_inode) { + static const struct qstr name = { .name = "/", .len = 1 }; + + res = __d_alloc(root_inode->i_sb, &name); + if (res) + d_instantiate(res, root_inode); + else + iput(root_inode); + } + return res; +} +EXPORT_SYMBOL(d_make_root); + static struct dentry * __d_find_any_alias(struct inode *inode) { struct dentry *alias; @@ -1472,7 +1475,14 @@ static struct dentry * __d_find_any_alias(struct inode *inode) return alias; } -static struct dentry * d_find_any_alias(struct inode *inode) +/** + * d_find_any_alias - find any alias for a given inode + * @inode: inode to find an alias for + * + * If any aliases exist for the given inode, take and return a + * reference for one of them. If no aliases exist, return %NULL. + */ +struct dentry *d_find_any_alias(struct inode *inode) { struct dentry *de; @@ -1481,7 +1491,7 @@ static struct dentry * d_find_any_alias(struct inode *inode) spin_unlock(&inode->i_lock); return de; } - +EXPORT_SYMBOL(d_find_any_alias); /** * d_obtain_alias - find or allocate a dentry for a given inode |