On Wed, May 09, 2007 at 02:09:50PM -0700, Jeremy Fitzhardinge wrote: > I've had a couple of instances of a linux-2.6 mercurial repo getting > corrupted in some odd way this morning. It looks like files are being > truncated; not to size 0, but losing something off the end. > > This is on an xfs filesystem. I haven't had any crashes/oops, and I > don't think its the normal files getting filled with 0 problem. I saw > this before the most recent set of xfs updates, but it happened again > afterwards too.
It looks like the latest XFS changes haven't been pulled yet, so it's not new code that is triggering this.... > Mercurial uses a strictly append-only model for updating its repo files, > but it looks like maybe an append operation didn't stick. > > I'm repulling a fresh copy of the repo; I'll be able to compare > before/after. Update: yep, definitely truncated: > > $ ls -l .hg-new/store/data/_documentation/pi-futex.txt.i > .hg-broken/store/data/_documentation/pi-futex.txt.i > 4 -rw-rw-r-- 1 jeremy jeremy 3309 May 9 09:43 > .hg-broken/store/data/_documentation/pi-futex.txt.i > 4 -rw-rw-r-- 1 jeremy jeremy 3797 May 9 13:38 > .hg-new/store/data/_documentation/pi-futex.txt.i > > also > 3476 -rw-rw-r-- 1 jeremy jeremy 3558208 May 9 13:55 00manifest.i > 3476 -rw-rw-r-- 1 jeremy jeremy 3555200 May 9 09:41 00manifest.i~ > > > where 00manifest.i~ is the broken one. The files are identical up to the > truncation point. Hmmm - that is bizarre. What is the output of xfs_bmap -vvp <filename> on each of those files? what happens to these files after then are downloaded? Does it only happen to append-only files or are other files affected as well? BTW, what's the 'xfs_info <mntpt>' output for this filesystem? > The repo passed "hg verify" just after I pulled it, so this corruption > came about after a while. > > Hm, the other possibility is that nlinks is being misreported. When > cloning a repo, mercurial will generally hard-link files where possible, > and then break the link if it sees nlink > 1. If xfs is mis-reporting > the link count, then this will cause havok. Is that possible? Seems > unlikely, but it would also explain the symptoms. I just did a linking > clone with an older kernel, and the link count is as expected. I'd be surprised if it was a link count problem - that would cause all sorts of other problems as well.... > xfs_check passes without any output, which I presume is good. Yes, it means everythign is ok. You only have to worry when xfs_check says something - it only brings bad news ;) Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
