On Tue, Jul 18, 2017 at 09:27:43PM +0300, Nikolay Borisov wrote: > > > 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 Ah, ok. That's what I suspected, so I'm glad to have confirmation. --D > > > > > > 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 -- 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
