diff options
| -rw-r--r-- | Documentation/filesystems/nfs/Exporting | 27 | ||||
| -rw-r--r-- | drivers/staging/lustre/lustre/llite/llite_internal.h | 10 | ||||
| -rw-r--r-- | fs/dcache.c | 22 | ||||
| -rw-r--r-- | fs/super.c | 2 | ||||
| -rw-r--r-- | include/linux/fs.h | 2 |
5 files changed, 34 insertions, 29 deletions
diff --git a/Documentation/filesystems/nfs/Exporting b/Documentation/filesystems/nfs/Exporting index 520a4becb75c..63889149f532 100644 --- a/Documentation/filesystems/nfs/Exporting +++ b/Documentation/filesystems/nfs/Exporting @@ -56,13 +56,25 @@ a/ A dentry flag DCACHE_DISCONNECTED which is set on any dentry that might not be part of the proper prefix. This is set when anonymous dentries are created, and cleared when a dentry is noticed to be a child of a dentry which is in the proper - prefix. - -b/ A per-superblock list "s_anon" of dentries which are the roots of - subtrees that are not in the proper prefix. These dentries, as - well as the proper prefix, need to be released at unmount time. As - these dentries will not be hashed, they are linked together on the - d_hash list_head. + prefix. If the refcount on a dentry with this flag set + becomes zero, the dentry is immediately discarded, rather than being + kept in the dcache. If a dentry that is not already in the dcache + is repeatedly accessed by filehandle (as NFSD might do), an new dentry + will be a allocated for each access, and discarded at the end of + the access. + + Note that such a dentry can acquire children, name, ancestors, etc. + without losing DCACHE_DISCONNECTED - that flag is only cleared when + subtree is successfully reconnected to root. Until then dentries + in such subtree are retained only as long as there are references; + refcount reaching zero means immediate eviction, same as for unhashed + dentries. That guarantees that we won't need to hunt them down upon + umount. + +b/ A primitive for creation of secondary roots - d_obtain_root(inode). + Those do _not_ bear DCACHE_DISCONNECTED. They are placed on the + per-superblock list (->s_roots), so they can be located at umount + time for eviction purposes. c/ Helper routines to allocate anonymous dentries, and to help attach loose directory dentries at lookup time. They are: @@ -77,7 +89,6 @@ c/ Helper routines to allocate anonymous dentries, and to help attach (such as an anonymous one created by d_obtain_alias), if appropriate. It returns NULL when the passed-in dentry is used, following the calling convention of ->lookup. - Filesystem Issues ----------------- diff --git a/drivers/staging/lustre/lustre/llite/llite_internal.h b/drivers/staging/lustre/lustre/llite/llite_internal.h index b133fd00c08c..0d62fcf016dc 100644 --- a/drivers/staging/lustre/lustre/llite/llite_internal.h +++ b/drivers/staging/lustre/lustre/llite/llite_internal.h @@ -1296,15 +1296,7 @@ static inline void d_lustre_invalidate(struct dentry *dentry, int nested) spin_lock_nested(&dentry->d_lock, nested ? DENTRY_D_LOCK_NESTED : DENTRY_D_LOCK_NORMAL); ll_d2d(dentry)->lld_invalid = 1; - /* - * We should be careful about dentries created by d_obtain_alias(). - * These dentries are not put in the dentry tree, instead they are - * linked to sb->s_anon through dentry->d_hash. - * shrink_dcache_for_umount() shrinks the tree and sb->s_anon list. - * If we unhashed such a dentry, unmount would not be able to find - * it and busy inodes would be reported. - */ - if (d_count(dentry) == 0 && !(dentry->d_flags & DCACHE_DISCONNECTED)) + if (d_count(dentry) == 0) __d_drop(dentry); spin_unlock(&dentry->d_lock); } diff --git a/fs/dcache.c b/fs/dcache.c index b99a39206930..17e6b84b9656 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -48,8 +48,8 @@ * - i_dentry, d_u.d_alias, d_inode of aliases * dcache_hash_bucket lock protects: * - the dcache hash table - * s_anon bl list spinlock protects: - * - the s_anon list (see __d_drop) + * s_roots bl list spinlock protects: + * - the s_roots list (see __d_drop) * dentry->d_sb->s_dentry_lru_lock protects: * - the dcache lru lists and counters * d_lock protects: @@ -67,7 +67,7 @@ * dentry->d_lock * dentry->d_sb->s_dentry_lru_lock * dcache_hash_bucket lock - * s_anon lock + * s_roots lock * * If there is an ancestor relationship: * dentry->d_parent->...->d_parent->d_lock @@ -476,10 +476,10 @@ void __d_drop(struct dentry *dentry) /* * Hashed dentries are normally on the dentry hashtable, * with the exception of those newly allocated by - * d_obtain_alias, which are always IS_ROOT: + * d_obtain_root, which are always IS_ROOT: */ if (unlikely(IS_ROOT(dentry))) - b = &dentry->d_sb->s_anon; + b = &dentry->d_sb->s_roots; else b = d_hash(dentry->d_name.hash); @@ -1499,8 +1499,8 @@ void shrink_dcache_for_umount(struct super_block *sb) sb->s_root = NULL; do_one_tree(dentry); - while (!hlist_bl_empty(&sb->s_anon)) { - dentry = dget(hlist_bl_entry(hlist_bl_first(&sb->s_anon), struct dentry, d_hash)); + while (!hlist_bl_empty(&sb->s_roots)) { + dentry = dget(hlist_bl_entry(hlist_bl_first(&sb->s_roots), struct dentry, d_hash)); do_one_tree(dentry); } } @@ -1964,9 +1964,11 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected) spin_lock(&tmp->d_lock); __d_set_inode_and_type(tmp, inode, add_flags); hlist_add_head(&tmp->d_u.d_alias, &inode->i_dentry); - hlist_bl_lock(&tmp->d_sb->s_anon); - hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon); - hlist_bl_unlock(&tmp->d_sb->s_anon); + if (!disconnected) { + hlist_bl_lock(&tmp->d_sb->s_roots); + hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_roots); + hlist_bl_unlock(&tmp->d_sb->s_roots); + } spin_unlock(&tmp->d_lock); spin_unlock(&inode->i_lock); diff --git a/fs/super.c b/fs/super.c index d4e33e8f1e6f..9ea66601d664 100644 --- a/fs/super.c +++ b/fs/super.c @@ -207,7 +207,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags, if (s->s_user_ns != &init_user_ns) s->s_iflags |= SB_I_NODEV; INIT_HLIST_NODE(&s->s_instances); - INIT_HLIST_BL_HEAD(&s->s_anon); + INIT_HLIST_BL_HEAD(&s->s_roots); mutex_init(&s->s_sync_lock); INIT_LIST_HEAD(&s->s_inodes); spin_lock_init(&s->s_inode_list_lock); diff --git a/include/linux/fs.h b/include/linux/fs.h index 2995a271ec46..6276f8315e5b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1359,7 +1359,7 @@ struct super_block { const struct fscrypt_operations *s_cop; - struct hlist_bl_head s_anon; /* anonymous dentries for (nfs) exporting */ + struct hlist_bl_head s_roots; /* alternate root dentries for NFS */ struct list_head s_mounts; /* list of mounts; _not_ for fs use */ struct block_device *s_bdev; struct backing_dev_info *s_bdi; |