diff options
| -rw-r--r-- | Documentation/filesystems/porting | 8 | ||||
| -rw-r--r-- | fs/dcache.c | 34 | ||||
| -rw-r--r-- | fs/inode.c | 1 | ||||
| -rw-r--r-- | include/linux/fs.h | 1 | ||||
| -rw-r--r-- | mm/shmem.c | 3 |
5 files changed, 44 insertions, 3 deletions
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 57bb3754a027..8810e2367fe6 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -531,3 +531,11 @@ in your dentry operations instead. dentry might be yet to be attached to inode, so do _not_ use its ->d_inode in the instances. Rationale: !@#!@# security_d_instantiate() needs to be called before we attach dentry to inode. +-- +[mandatory] + symlinks are no longer the only inodes that do *not* have i_bdev/i_cdev/ + i_pipe/i_link union zeroed out at inode eviction. As the result, you can't + assume that non-NULL value in ->i_nlink at ->destroy_inode() implies that + it's a symlink. Checking ->i_mode is really needed now. In-tree we had + to fix shmem_destroy_callback() that used to take that kind of shortcut; + watch out, since that shortcut is no longer valid. diff --git a/fs/dcache.c b/fs/dcache.c index 0f1d93866e69..10988f7e5a23 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2364,6 +2364,22 @@ void d_rehash(struct dentry * entry) } EXPORT_SYMBOL(d_rehash); +static inline unsigned start_dir_add(struct inode *dir) +{ + + for (;;) { + unsigned n = dir->i_dir_seq; + if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n) + return n; + cpu_relax(); + } +} + +static inline void end_dir_add(struct inode *dir, unsigned n) +{ + smp_store_release(&dir->i_dir_seq, n + 2); +} + void __d_lookup_done(struct dentry *dentry) { dentry->d_flags &= ~DCACHE_PAR_LOOKUP; @@ -2375,9 +2391,14 @@ EXPORT_SYMBOL(__d_lookup_done); static inline void __d_add(struct dentry *dentry, struct inode *inode) { + struct inode *dir = NULL; + unsigned n; spin_lock(&dentry->d_lock); - if (unlikely(d_in_lookup(dentry))) + if (unlikely(d_in_lookup(dentry))) { + dir = dentry->d_parent->d_inode; + n = start_dir_add(dir); __d_lookup_done(dentry); + } if (inode) { unsigned add_flags = d_flags_for_inode(inode); hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry); @@ -2387,6 +2408,8 @@ static inline void __d_add(struct dentry *dentry, struct inode *inode) __fsnotify_d_instantiate(dentry); } _d_rehash(dentry); + if (dir) + end_dir_add(dir, n); spin_unlock(&dentry->d_lock); if (inode) spin_unlock(&inode->i_lock); @@ -2616,6 +2639,8 @@ static void dentry_unlock_for_move(struct dentry *dentry, struct dentry *target) static void __d_move(struct dentry *dentry, struct dentry *target, bool exchange) { + struct inode *dir = NULL; + unsigned n; if (!dentry->d_inode) printk(KERN_WARNING "VFS: moving negative dcache entry\n"); @@ -2623,8 +2648,11 @@ static void __d_move(struct dentry *dentry, struct dentry *target, BUG_ON(d_ancestor(target, dentry)); dentry_lock_for_move(dentry, target); - if (unlikely(d_in_lookup(target))) + if (unlikely(d_in_lookup(target))) { + dir = target->d_parent->d_inode; + n = start_dir_add(dir); __d_lookup_done(target); + } write_seqcount_begin(&dentry->d_seq); write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED); @@ -2674,6 +2702,8 @@ static void __d_move(struct dentry *dentry, struct dentry *target, write_seqcount_end(&target->d_seq); write_seqcount_end(&dentry->d_seq); + if (dir) + end_dir_add(dir, n); dentry_unlock_for_move(dentry, target); } diff --git a/fs/inode.c b/fs/inode.c index 4202aac99464..4b884f73214e 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -151,6 +151,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode) inode->i_bdev = NULL; inode->i_cdev = NULL; inode->i_link = NULL; + inode->i_dir_seq = 0; inode->i_rdev = 0; inode->dirtied_when = 0; diff --git a/include/linux/fs.h b/include/linux/fs.h index 6d0fa9174a24..00cecc5a2f75 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -684,6 +684,7 @@ struct inode { struct block_device *i_bdev; struct cdev *i_cdev; char *i_link; + unsigned i_dir_seq; }; __u32 i_generation; diff --git a/mm/shmem.c b/mm/shmem.c index 4640699b209b..e684a9140228 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -3123,7 +3123,8 @@ static struct inode *shmem_alloc_inode(struct super_block *sb) static void shmem_destroy_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); - kfree(inode->i_link); + if (S_ISLNK(inode->i_mode)) + kfree(inode->i_link); kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); } |