On Fri, Apr 13, 2012 at 04:58:15PM +0200, Jan Schmidt wrote: > commit 7a3ae2f8c8c8432e65467b7fc84d5deab04061a0 upstream. > > In commit 4692cf58 (Linux 3.3) we introduced new backref walking code for > btrfs. This assumes we're searching live roots, which requires a transaction > context. While scrubbing, however, we must not join a transaction because > this could deadlock with the commit path: > > Can be exploited by corrupting data in btrfs (e.g. btrfs-corrupt-block) and > then starting a scrub job (btrfs scrub). This will find the corrupt block > and resolve the file paths affected. If that happens while btrfs is about to > commit its transaction, a deadlock occurs: The scrub process prevents the > commit from completing, while the path resolving code joins a transaction > which blocks until the current transaction completes. > > Additionally, what scrub really wants to do is resolving a logical address > in the commit root it's currently checking. This patch adds support for > logical to path resolving on commit roots and makes scrub use that. > > Signed-off-by: Jan Schmidt <[email protected]> > Signed-off-by: Chris Mason <[email protected]> > --- > > I know, it's quite big for a stable patch. Anyway, it fixes a 3.3 regression > and should therefore be included in the next 3.3-stable release. Tested on > top of Linux 3.3.1.
I'll include it if Chris gives his ack for it. Chris? -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
