Messages in this thread Patch in this message | | | Date | Thu, 11 Mar 2010 12:53:33 -0500 (EST) | From | Sachin Prabhu <> | Subject | [PATCH] v9fs: Skip check for mandatory locks when unlocking |
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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> diff -up linux-2.6/fs/9p/vfs_file.c.9p linux-2.6/fs/9p/vfs_file.c --- linux-2.6/fs/9p/vfs_file.c.9p 2010-03-11 17:32:52.000000000 +0000 +++ linux-2.6/fs/9p/vfs_file.c 2010-03-11 17:33:11.000000000 +0000 @@ -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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