diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-09-28 10:02:53 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-09-28 10:02:53 -0700 |
| commit | 7596824e6626c62557b9eb6411ee74fec68b8ff9 (patch) | |
| tree | 4a906422538887be858b9cbdf848d68f8db6c116 | |
| parent | 97956605d8f2a0d17706cbd338a6cfe8de1920e9 (diff) | |
| parent | c5aa1e554a20fb3542c62688ae46049c9225a965 (diff) | |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:
"A couple of fixes; one for automount/lazy umount race, another a
classic "we don't protect the refcount transition to zero with the
lock that protects looking for object in hash" kind of crap in lockd."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
close the race in nlmsvc_free_block()
do_add_mount()/umount -l races
| -rw-r--r-- | fs/lockd/svclock.c | 3 | ||||
| -rw-r--r-- | fs/namespace.c | 10 |
2 files changed, 9 insertions, 4 deletions
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c index fb1a2bedbe9..8d80c990dff 100644 --- a/fs/lockd/svclock.c +++ b/fs/lockd/svclock.c @@ -289,7 +289,6 @@ static void nlmsvc_free_block(struct kref *kref) dprintk("lockd: freeing block %p...\n", block); /* Remove block from file's list of blocks */ - mutex_lock(&file->f_mutex); list_del_init(&block->b_flist); mutex_unlock(&file->f_mutex); @@ -303,7 +302,7 @@ static void nlmsvc_free_block(struct kref *kref) static void nlmsvc_release_block(struct nlm_block *block) { if (block != NULL) - kref_put(&block->b_count, nlmsvc_free_block); + kref_put_mutex(&block->b_count, nlmsvc_free_block, &block->b_file->f_mutex); } /* diff --git a/fs/namespace.c b/fs/namespace.c index 4d31f73e256..7bdf7907413 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1886,8 +1886,14 @@ static int do_add_mount(struct mount *newmnt, struct path *path, int mnt_flags) return err; err = -EINVAL; - if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(real_mount(path->mnt))) - goto unlock; + if (unlikely(!check_mnt(real_mount(path->mnt)))) { + /* that's acceptable only for automounts done in private ns */ + if (!(mnt_flags & MNT_SHRINKABLE)) + goto unlock; + /* ... and for those we'd better have mountpoint still alive */ + if (!real_mount(path->mnt)->mnt_ns) + goto unlock; + } /* Refuse the same filesystem on the same mount point */ err = -EBUSY; |