From 873feea09ebc980cbd3631b767356ce1eee65ec1 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 7 Jan 2011 17:50:06 +1100 Subject: [PATCH] fs: dcache per-inode inode alias locking dcache_inode_lock can be replaced with per-inode locking. Use existing inode->i_lock for this. This is slightly non-trivial because we sometimes need to find the inode from the dentry, which requires d_inode to be stabilised (either with refcount or d_lock). Signed-off-by: Nick Piggin --- fs/9p/vfs_inode.c | 4 +- fs/affs/amigaffs.c | 4 +- fs/cifs/inode.c | 6 +-- fs/dcache.c | 88 ++++++++++++++++++++++-------------------- fs/exportfs/expfs.c | 12 +++--- fs/nfs/getroot.c | 4 +- fs/notify/fsnotify.c | 4 +- fs/ocfs2/dcache.c | 4 +- include/linux/dcache.h | 1 - 9 files changed, 67 insertions(+), 60 deletions(-) diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c index df8bbb358d5..59782981b22 100644 --- a/fs/9p/vfs_inode.c +++ b/fs/9p/vfs_inode.c @@ -277,11 +277,11 @@ static struct dentry *v9fs_dentry_from_dir_inode(struct inode *inode) { struct dentry *dentry; - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); /* Directory should have only one entry. */ BUG_ON(S_ISDIR(inode->i_mode) && !list_is_singular(&inode->i_dentry)); dentry = list_entry(inode->i_dentry.next, struct dentry, d_alias); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); return dentry; } diff --git a/fs/affs/amigaffs.c b/fs/affs/amigaffs.c index 600101a21ba..3a4557e8325 100644 --- a/fs/affs/amigaffs.c +++ b/fs/affs/amigaffs.c @@ -128,7 +128,7 @@ affs_fix_dcache(struct dentry *dentry, u32 entry_ino) void *data = dentry->d_fsdata; struct list_head *head, *next; - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); head = &inode->i_dentry; next = head->next; while (next != head) { @@ -139,7 +139,7 @@ affs_fix_dcache(struct dentry *dentry, u32 entry_ino) } next = next->next; } - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); } diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c index 2a239d878e8..a853a89857a 100644 --- a/fs/cifs/inode.c +++ b/fs/cifs/inode.c @@ -809,14 +809,14 @@ inode_has_hashed_dentries(struct inode *inode) { struct dentry *dentry; - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); list_for_each_entry(dentry, &inode->i_dentry, d_alias) { if (!d_unhashed(dentry) || IS_ROOT(dentry)) { - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); return true; } } - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); return false; } diff --git a/fs/dcache.c b/fs/dcache.c index 9f04e1ba75b..09ec945f3c9 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -39,8 +39,8 @@ /* * Usage: - * dcache_inode_lock protects: - * - i_dentry, d_alias, d_inode + * dcache->d_inode->i_lock protects: + * - i_dentry, d_alias, d_inode of aliases * dcache_hash_bucket lock protects: * - the dcache hash table * s_anon bl list spinlock protects: @@ -58,7 +58,7 @@ * - d_alias, d_inode * * Ordering: - * dcache_inode_lock + * dentry->d_inode->i_lock * dentry->d_lock * dcache_lru_lock * dcache_hash_bucket lock @@ -78,12 +78,10 @@ int sysctl_vfs_cache_pressure __read_mostly = 100; EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure); -__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_inode_lock); static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lru_lock); __cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock); EXPORT_SYMBOL(rename_lock); -EXPORT_SYMBOL(dcache_inode_lock); static struct kmem_cache *dentry_cache __read_mostly; @@ -196,14 +194,14 @@ static inline void dentry_rcuwalk_barrier(struct dentry *dentry) */ static void dentry_iput(struct dentry * dentry) __releases(dentry->d_lock) - __releases(dcache_inode_lock) + __releases(dentry->d_inode->i_lock) { struct inode *inode = dentry->d_inode; if (inode) { dentry->d_inode = NULL; list_del_init(&dentry->d_alias); spin_unlock(&dentry->d_lock); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); if (!inode->i_nlink) fsnotify_inoderemove(inode); if (dentry->d_op && dentry->d_op->d_iput) @@ -212,7 +210,6 @@ static void dentry_iput(struct dentry * dentry) iput(inode); } else { spin_unlock(&dentry->d_lock); - spin_unlock(&dcache_inode_lock); } } @@ -222,14 +219,14 @@ static void dentry_iput(struct dentry * dentry) */ static void dentry_unlink_inode(struct dentry * dentry) __releases(dentry->d_lock) - __releases(dcache_inode_lock) + __releases(dentry->d_inode->i_lock) { struct inode *inode = dentry->d_inode; dentry->d_inode = NULL; list_del_init(&dentry->d_alias); dentry_rcuwalk_barrier(dentry); spin_unlock(&dentry->d_lock); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); if (!inode->i_nlink) fsnotify_inoderemove(inode); if (dentry->d_op && dentry->d_op->d_iput) @@ -295,7 +292,7 @@ static void dentry_lru_move_tail(struct dentry *dentry) static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent) __releases(dentry->d_lock) __releases(parent->d_lock) - __releases(dcache_inode_lock) + __releases(dentry->d_inode->i_lock) { dentry->d_parent = NULL; list_del(&dentry->d_u.d_child); @@ -370,9 +367,11 @@ EXPORT_SYMBOL(d_drop); static inline struct dentry *dentry_kill(struct dentry *dentry, int ref) __releases(dentry->d_lock) { + struct inode *inode; struct dentry *parent; - if (!spin_trylock(&dcache_inode_lock)) { + inode = dentry->d_inode; + if (inode && !spin_trylock(&inode->i_lock)) { relock: spin_unlock(&dentry->d_lock); cpu_relax(); @@ -383,7 +382,8 @@ relock: else parent = dentry->d_parent; if (parent && !spin_trylock(&parent->d_lock)) { - spin_unlock(&dcache_inode_lock); + if (inode) + spin_unlock(&inode->i_lock); goto relock; } @@ -618,9 +618,9 @@ struct dentry *d_find_alias(struct inode *inode) struct dentry *de = NULL; if (!list_empty(&inode->i_dentry)) { - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); de = __d_find_alias(inode, 0); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); } return de; } @@ -634,20 +634,20 @@ void d_prune_aliases(struct inode *inode) { struct dentry *dentry; restart: - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); list_for_each_entry(dentry, &inode->i_dentry, d_alias) { spin_lock(&dentry->d_lock); if (!dentry->d_count) { __dget_dlock(dentry); __d_drop(dentry); spin_unlock(&dentry->d_lock); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); dput(dentry); goto restart; } spin_unlock(&dentry->d_lock); } - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); } EXPORT_SYMBOL(d_prune_aliases); @@ -1392,9 +1392,11 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode) void d_instantiate(struct dentry *entry, struct inode * inode) { BUG_ON(!list_empty(&entry->d_alias)); - spin_lock(&dcache_inode_lock); + if (inode) + spin_lock(&inode->i_lock); __d_instantiate(entry, inode); - spin_unlock(&dcache_inode_lock); + if (inode) + spin_unlock(&inode->i_lock); security_d_instantiate(entry, inode); } EXPORT_SYMBOL(d_instantiate); @@ -1458,9 +1460,11 @@ struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) BUG_ON(!list_empty(&entry->d_alias)); - spin_lock(&dcache_inode_lock); + if (inode) + spin_lock(&inode->i_lock); result = __d_instantiate_unique(entry, inode); - spin_unlock(&dcache_inode_lock); + if (inode) + spin_unlock(&inode->i_lock); if (!result) { security_d_instantiate(entry, inode); @@ -1542,10 +1546,10 @@ struct dentry *d_obtain_alias(struct inode *inode) tmp->d_parent = tmp; /* make sure dput doesn't croak */ - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); res = __d_find_alias(inode, 0); if (res) { - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); dput(tmp); goto out_iput; } @@ -1561,7 +1565,7 @@ struct dentry *d_obtain_alias(struct inode *inode) hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon); __bit_spin_unlock(0, (unsigned long *)&tmp->d_sb->s_anon.first); spin_unlock(&tmp->d_lock); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); return tmp; @@ -1592,18 +1596,18 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) struct dentry *new = NULL; if (inode && S_ISDIR(inode->i_mode)) { - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); new = __d_find_alias(inode, 1); if (new) { BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED)); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); security_d_instantiate(new, inode); d_move(new, dentry); iput(inode); } else { - /* already got dcache_inode_lock, so d_add() by hand */ + /* already taking inode->i_lock, so d_add() by hand */ __d_instantiate(dentry, inode); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); security_d_instantiate(dentry, inode); d_rehash(dentry); } @@ -1676,10 +1680,10 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, * Negative dentry: instantiate it unless the inode is a directory and * already has a dentry. */ - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); if (!S_ISDIR(inode->i_mode) || list_empty(&inode->i_dentry)) { __d_instantiate(found, inode); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); security_d_instantiate(found, inode); return found; } @@ -1690,7 +1694,7 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, */ new = list_entry(inode->i_dentry.next, struct dentry, d_alias); __dget(new); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); security_d_instantiate(found, inode); d_move(new, found); iput(inode); @@ -2004,15 +2008,17 @@ EXPORT_SYMBOL(d_validate); void d_delete(struct dentry * dentry) { + struct inode *inode; int isdir = 0; /* * Are we the only user? */ again: spin_lock(&dentry->d_lock); - isdir = S_ISDIR(dentry->d_inode->i_mode); + inode = dentry->d_inode; + isdir = S_ISDIR(inode->i_mode); if (dentry->d_count == 1) { - if (!spin_trylock(&dcache_inode_lock)) { + if (inode && !spin_trylock(&inode->i_lock)) { spin_unlock(&dentry->d_lock); cpu_relax(); goto again; @@ -2266,13 +2272,13 @@ struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) * This helper attempts to cope with remotely renamed directories * * It assumes that the caller is already holding - * dentry->d_parent->d_inode->i_mutex and the dcache_inode_lock + * dentry->d_parent->d_inode->i_mutex and the inode->i_lock * * Note: If ever the locking in lock_rename() changes, then please * remember to update this too... */ -static struct dentry *__d_unalias(struct dentry *dentry, struct dentry *alias) - __releases(dcache_inode_lock) +static struct dentry *__d_unalias(struct inode *inode, + struct dentry *dentry, struct dentry *alias) { struct mutex *m1 = NULL, *m2 = NULL; struct dentry *ret; @@ -2298,7 +2304,7 @@ out_unalias: d_move(alias, dentry); ret = alias; out_err: - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); if (m2) mutex_unlock(m2); if (m1) @@ -2371,7 +2377,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) goto out_nolock; } - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); if (S_ISDIR(inode->i_mode)) { struct dentry *alias; @@ -2388,7 +2394,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) goto found; } /* Nope, but we must(!) avoid directory aliasing */ - actual = __d_unalias(dentry, alias); + actual = __d_unalias(inode, dentry, alias); if (IS_ERR(actual)) dput(alias); goto out_nolock; @@ -2406,7 +2412,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) found: _d_rehash(actual); spin_unlock(&actual->d_lock); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); out_nolock: if (actual == dentry) { security_d_instantiate(dentry, inode); diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index f06a940065f..4b6825740dd 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -43,24 +43,26 @@ find_acceptable_alias(struct dentry *result, void *context) { struct dentry *dentry, *toput = NULL; + struct inode *inode; if (acceptable(context, result)) return result; - spin_lock(&dcache_inode_lock); - list_for_each_entry(dentry, &result->d_inode->i_dentry, d_alias) { + inode = result->d_inode; + spin_lock(&inode->i_lock); + list_for_each_entry(dentry, &inode->i_dentry, d_alias) { dget(dentry); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); if (toput) dput(toput); if (dentry != result && acceptable(context, dentry)) { dput(result); return dentry; } - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); toput = dentry; } - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); if (toput) dput(toput); diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c index c3a5a112683..5596c6a2881 100644 --- a/fs/nfs/getroot.c +++ b/fs/nfs/getroot.c @@ -63,11 +63,11 @@ static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *i * This again causes shrink_dcache_for_umount_subtree() to * Oops, since the test for IS_ROOT() will fail. */ - spin_lock(&dcache_inode_lock); + spin_lock(&sb->s_root->d_inode->i_lock); spin_lock(&sb->s_root->d_lock); list_del_init(&sb->s_root->d_alias); spin_unlock(&sb->s_root->d_lock); - spin_unlock(&dcache_inode_lock); + spin_unlock(&sb->s_root->d_inode->i_lock); } return 0; } diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 9be6ec1f36d..79b47cbb5cd 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -59,7 +59,7 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode) /* determine if the children should tell inode about their events */ watched = fsnotify_inode_watches_children(inode); - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); /* run all of the dentries associated with this inode. Since this is a * directory, there damn well better only be one item on this list */ list_for_each_entry(alias, &inode->i_dentry, d_alias) { @@ -82,7 +82,7 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode) } spin_unlock(&alias->d_lock); } - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); } /* Notify this dentry's parent about a child's events. */ diff --git a/fs/ocfs2/dcache.c b/fs/ocfs2/dcache.c index 0310b16a723..6d80ecc7834 100644 --- a/fs/ocfs2/dcache.c +++ b/fs/ocfs2/dcache.c @@ -175,7 +175,7 @@ struct dentry *ocfs2_find_local_alias(struct inode *inode, struct list_head *p; struct dentry *dentry = NULL; - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); list_for_each(p, &inode->i_dentry) { dentry = list_entry(p, struct dentry, d_alias); @@ -193,7 +193,7 @@ struct dentry *ocfs2_find_local_alias(struct inode *inode, dentry = NULL; } - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); return dentry; } diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 5f0392ef759..d719e4de804 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -191,7 +191,6 @@ struct dentry_operations { #define DCACHE_OP_REVALIDATE 0x4000 #define DCACHE_OP_DELETE 0x8000 -extern spinlock_t dcache_inode_lock; extern seqlock_t rename_lock; static inline int dname_external(struct dentry *dentry) -- 2.20.1