tree bafe176811479d922e2f19f4386f34a11a30c39f
parent 98b5c10d320adfa250c1c18f3ccaec2f78e5e11d
author Eric Paris <eparis@redhat.com> 1271882978 -0400
committer Eric Paris <eparis@redhat.com> 1280325542 -0400

fsnotify: call iput on inodes when no longer marked

fsnotify takes an igrab on an inode when it adds a mark.  The code was
supposed to drop the reference when the mark was removed but didn't.
This caused problems when an fs was unmounted because those inodes would
clearly not be gone.  Thus resulting in the most devistating of messages:

VFS: Busy inodes after unmount of loop0. Self-destruct in 5 seconds.
>>> Have a nice day...

Jiri Slaby bisected the problem to a patch in the fsnotify tree.  The
code snippets below show my stupidity quite clearly.

void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark)
{
	...
	mark->inode = NULL;
	...
}

void fsnotify_destroy_mark(struct fsnotify_mark *mark)
{
	struct inode *inode = NULL;
	...
	if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) {
		fsnotify_destroy_inode_mark(mark);
		inode = mark->i.inode;
	}
	...
	if (inode)
		iput(inode);
	...
}

Obviously the intent was to capture the inode before it was set to NULL in
fsnotify_destory_inode_mark() so we wouldn't be leaking inodes forever.
Instead we leaked them (and exploded on umount)

Reported-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Eric Paris <eparis@redhat.com>