On Tue, Dec 20, 2011 at 03:08:41PM -0500, Christoph Hellwig wrote: > Since Linux 2.6.36 the writeback code has introduces various measures for > live lock prevention during sync(). Unfortunately some of these are > actively harmful for the XFS model, where the inode gets marked dirty for > metadata from the data I/O handler. > > The older_than_this checks that are now more strictly enforced since > > writeback: avoid livelocking WB_SYNC_ALL writeback > > by only calling into __writeback_inodes_sb and thus only sampling the > current cut off time once. But on a slow enough devices the previous > asynchronous sync pass might not have fully completed yet, and thus XFS > might mark metadata dirty only after that sampling of the cut off time for > the blocking pass already happened. I have not myself reproduced this > myself on a real system, but by introducing artificial delay into the > XFS I/O completion workqueues it can be reproduced easily. > > Fix this by iterating over all XFS inodes in ->sync_fs and log all that > are dirty. This might log inode that only got redirtied after the > previous pass, but given how cheap delayed logging of inodes is it > isn't a major concern for performance. > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> Looks OK now. Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx> -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
