On Mon, Nov 19, 2012 at 10:39:13PM +0100, Jan Kara wrote: > On Tue 13-11-12 01:36:13, Jan Kara wrote: > > When project quota gets exceeded xfs_iomap_write_delay() ends up flushing > > inodes because ENOSPC gets returned from xfs_bmapi_delay() instead of EDQUOT. > > This makes handling of writes over project quota rather slow as a simple test > > program shows: > > fd = open(argv[1], O_WRONLY | O_CREAT | O_TRUNC, 0644); > > for (i = 0; i < 50000; i++) > > pwrite(fd, buf, 4096, i*4096); > > > > Writing 200 MB like this into a directory with 100 MB project quota takes > > around 6 minutes while it takes about 2 seconds with this patch applied. This > > actually happens in a real world load when nfs pushes data into a directory > > which is over project quota. > > > > Fix the problem by replacing XFS_QMOPT_ENOSPC flag with XFS_QMOPT_EPDQUOT. > > That makes xfs_trans_reserve_quota_bydquots() return new error EPDQUOT when > > project quota is exceeded. xfs_bmapi_delay() then uses this flag so that > > xfs_iomap_write_delay() can distinguish real ENOSPC (requiring flushing) > > from exceeded project quota (not requiring flushing). > > > > As a side effect this patch fixes inconsistency where e.g. xfs_create() > > returned EDQUOT even when project quota was exceeded. > Ping? Any opinions? FWIW, it doesn't look like it'll apply to a current XFs tree: > > @@ -441,8 +442,11 @@ retry: > > */ > > if (nimaps == 0) { > > trace_xfs_delalloc_enospc(ip, offset, count); > > - if (flushed) > > - return XFS_ERROR(error ? error : ENOSPC); > > + if (flushed) { > > + if (error == 0 || error == EPDQUOT) > > + error = ENOSPC; > > + return XFS_ERROR(error); > > + } > > > > if (error == ENOSPC) { > > xfs_iunlock(ip, XFS_ILOCK_EXCL); This xfs_iomap_write_delay() looks like this now: /* * If bmapi returned us nothing, we got either ENOSPC or EDQUOT. Retry * without EOF preallocation. */ if (nimaps == 0) { trace_xfs_delalloc_enospc(ip, offset, count); if (prealloc) { prealloc = 0; error = 0; goto retry; } return XFS_ERROR(error ? error : ENOSPC); } The flushing is now way up in xfs_file_buffered_aio_write(), and the implementation of xfs_flush_inodes() has changed as well. Hence it may or may not behave differently not.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs