On Jun 20, 2017, at 12:20 PM, Darrick J. Wong <darrick.wong@xxxxxxxxxx> wrote: >> Now that you have an idea of what caused the issue, is there some way >> to (easily or not) reproduce it, ideally in userspace? Part of the >> problem we're having is that we can't reproduce it on a test machine >> so are forced to wait for it to happen in the field under load, where >> it inconveniences users. > > I know what caused the crash, but I don't know what caused the hole in > the xattr fork that caused the crash. It would appear that the xattr > hash tree contains a pointer to an xattr fork offset that is no longer > mapped, but I don't know how we end up with a dangling pointer -- > whether this is corruption going on in the attribute fork, or merely a > bug in the routine that tears down the attribute fork and accidentally > tries to delete something twice. > > Unfortunately, the metadumps you've both sent me don't seem to contain > any inodes with sparse attribute forks, so evidently something cleaned > up the filesystem before the metadump was taken. The filesystems were automatically mounted after the box rebooted. Could the mount (via replaying the journal) have cleaned things up? I have a reproduction case for this now - it takes several hours, but can reliably cause this panic. I will send you a new metadump that was not mounted after the failure. > It might help to know a little more about what's going on with the > xattrs that are being attached to those files. A fair number of the > inodes seem to have extended attributes with 2k values attached. Does > your workload involve adding and deleting a large number of xattrs? A > number of large xattrs? A large number of large xattrs? All of the above. This is Samba with the alternate data streams module (vfs_streams_xattr), which stores the ADS in xattrs. It makes for some large xattrs. David -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
