From f78233dd44a110c574fe760ad6f9c1e8741a0d00 Mon Sep 17 00:00:00 2001 From: Sachin Prabhu Date: Sat, 13 Mar 2010 09:03:55 -0600 Subject: 9p: Skip check for mandatory locks when unlocking 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 Signed-off-by: Eric Van Hensbergen diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c index 019f1cd..df52d48 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -114,7 +114,7 @@ static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl) 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) { -- cgit v0.10.2