| Date | Thu, 22 Apr 2010 12:54:31 -0700 | From | Greg KH <> | Subject | [094/139] 9p: Skip check for mandatory locks when unlocking |
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2.6.33-stable review patch. If anyone has any objections, please let us know.
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From: Sachin Prabhu <sprabhu@redhat.com>
commit f78233dd44a110c574fe760ad6f9c1e8741a0d00 upstream.
While investigating a bug, I came across a possible bug in v9fs. The problem is similar to the one reported for NFS by ASANO Masahiro in http://lkml.org/lkml/2005/12/21/334.
v9fs_file_lock() will skip locks on file which has mode set to 02666. This is a problem in cases where the mode of the file is changed after a process has obtained a lock on the file. Such a lock will be skipped during unlock and the machine will end up with a BUG in locks_remove_flock().
v9fs_file_lock() should skip the check for mandatory locks when unlocking a file.
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com> Cc: maximilian attems <max@stro.at> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/9p/vfs_file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -114,7 +114,7 @@ static int v9fs_file_lock(struct file *f P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl); /* No mandatory locks */ - if (__mandatory_lock(inode)) + if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) return -ENOLCK; if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
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