On 18.07.2017 21:15, Darrick J. Wong wrote: > On Tue, Jul 18, 2017 at 07:25:45PM +0200, Christoph Hellwig wrote: >> Just like in the allocator we must avoid touching multiple AGs out of >> order when freeing blocks, as freeing still locks the AGF and can cause >> the same AB-BA deadlocks as in the allocation path. >> >> Signed-off-by: Christoph Hellwig <hch@xxxxxx> >> Reported-by: Nikolay Borisov <n.borisov.lkml@xxxxxxxxx> > > Looks ok, though I wonder what the bug report looked like. :) https://www.spinics.net/lists/linux-xfs/msg05918.html > > Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > >> --- >> fs/xfs/libxfs/xfs_bmap.c | 12 ++++++++++++ >> 1 file changed, 12 insertions(+) >> >> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c >> index 0a9880777c9c..935adde72a8b 100644 >> --- a/fs/xfs/libxfs/xfs_bmap.c >> +++ b/fs/xfs/libxfs/xfs_bmap.c >> @@ -5435,6 +5435,7 @@ __xfs_bunmapi( >> xfs_fsblock_t sum; >> xfs_filblks_t len = *rlen; /* length to unmap in file */ >> xfs_fileoff_t max_len; >> + xfs_agnumber_t prev_agno = NULLAGNUMBER, agno; >> >> trace_xfs_bunmap(ip, bno, len, flags, _RET_IP_); >> >> @@ -5534,6 +5535,17 @@ __xfs_bunmapi( >> */ >> del = got; >> wasdel = isnullstartblock(del.br_startblock); >> + >> + /* >> + * Make sure we don't touch multiple AGF headers out of order >> + * in a single transaction, as that could cause AB-BA deadlocks. >> + */ >> + if (!wasdel) { >> + agno = XFS_FSB_TO_AGNO(mp, del.br_startblock); >> + if (prev_agno != NULLAGNUMBER && prev_agno > agno) >> + break; >> + prev_agno = agno; >> + } >> if (got.br_startoff < start) { >> del.br_startoff = start; >> del.br_blockcount -= start - got.br_startoff; >> -- >> 2.11.0 >> >> -- >> 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 -- 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
