diff options
| author |   Jeff Layton <jlayton@redhat.com> | 2014-03-10 09:54:15 -0400 |
|---|---|---|
| committer | Jeff Layton <jlayton@redhat.com> | 2014-03-31 08:24:43 -0400 |
| commit | d7a06983a01a33605191c0766857b832ac32a2b6 (patch) | |
| tree | d6a0f83579e0d7a20a235ddb568d935fe54b24fb /fs | |
| parent | locks: require that flock->l_pid be set to 0 for file-private locks (diff) | |
| download | linux-dev-d7a06983a01a33605191c0766857b832ac32a2b6.tar.xz linux-dev-d7a06983a01a33605191c0766857b832ac32a2b6.zip | |
locks: fix locks_mandatory_locked to respect file-private locks
As Trond pointed out, you can currently deadlock yourself by setting a
file-private lock on a file that requires mandatory locking and then
trying to do I/O on it.
Avoid this problem by plumbing some knowledge of file-private locks into
the mandatory locking code. In order to do this, we must pass down
information about the struct file that's being used to
locks_verify_locked.
Reported-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/locks.c | 7 | ||||
| -rw-r--r-- | fs/namei.c | 2 |
2 files changed, 5 insertions, 4 deletions
diff --git a/fs/locks.c b/fs/locks.c index 09d6c8c33c81..d82c51c4fcd2 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1155,13 +1155,14 @@ EXPORT_SYMBOL(posix_lock_file_wait); /** * locks_mandatory_locked - Check for an active lock - * @inode: the file to check + * @file: the file to check * * Searches the inode's list of locks to find any POSIX locks which conflict. * This function is called from locks_verify_locked() only. */ -int locks_mandatory_locked(struct inode *inode) +int locks_mandatory_locked(struct file *file) { + struct inode *inode = file_inode(file); fl_owner_t owner = current->files; struct file_lock *fl; @@ -1172,7 +1173,7 @@ int locks_mandatory_locked(struct inode *inode) for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { if (!IS_POSIX(fl)) continue; - if (fl->fl_owner != owner) + if (fl->fl_owner != owner && fl->fl_owner != (fl_owner_t)file) break; } spin_unlock(&inode->i_lock); diff --git a/fs/namei.c b/fs/namei.c index d580df2e6804..dc51bac037c9 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2542,7 +2542,7 @@ static int handle_truncate(struct file *filp) /* * Refuse to truncate files with mandatory locks held on them. */ - error = locks_verify_locked(inode); + error = locks_verify_locked(filp); if (!error) error = security_path_truncate(path); if (!error) { |