| From 4b85b0e005678a575befec472fd7874b97ac6771 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 14 Jul 2020 10:36:08 -0700 |
| Subject: xfs: clear XFS_DQ_FREEING if we can't lock the dquot buffer to flush |
| |
| From: Darrick J. Wong <darrick.wong@oracle.com> |
| |
| [ Upstream commit c97738a960a86081a147e7d436138e6481757445 ] |
| |
| In commit 8d3d7e2b35ea, we changed xfs_qm_dqpurge to bail out if we |
| can't lock the dquot buf to flush the dquot. This prevents the AIL from |
| blocking on the dquot, but it also forgets to clear the FREEING flag on |
| its way out. A subsequent purge attempt will see the FREEING flag is |
| set and bail out, which leads to dqpurge_all failing to purge all the |
| dquots. |
| |
| (copy-pasting from Dave Chinner's identical patch) |
| |
| This was found by inspection after having xfs/305 hang 1 in ~50 |
| iterations in a quotaoff operation: |
| |
| [ 8872.301115] xfs_quota D13888 92262 91813 0x00004002 |
| [ 8872.302538] Call Trace: |
| [ 8872.303193] __schedule+0x2d2/0x780 |
| [ 8872.304108] ? do_raw_spin_unlock+0x57/0xd0 |
| [ 8872.305198] schedule+0x6e/0xe0 |
| [ 8872.306021] schedule_timeout+0x14d/0x300 |
| [ 8872.307060] ? __next_timer_interrupt+0xe0/0xe0 |
| [ 8872.308231] ? xfs_qm_dqusage_adjust+0x200/0x200 |
| [ 8872.309422] schedule_timeout_uninterruptible+0x2a/0x30 |
| [ 8872.310759] xfs_qm_dquot_walk.isra.0+0x15a/0x1b0 |
| [ 8872.311971] xfs_qm_dqpurge_all+0x7f/0x90 |
| [ 8872.313022] xfs_qm_scall_quotaoff+0x18d/0x2b0 |
| [ 8872.314163] xfs_quota_disable+0x3a/0x60 |
| [ 8872.315179] kernel_quotactl+0x7e2/0x8d0 |
| [ 8872.316196] ? __do_sys_newstat+0x51/0x80 |
| [ 8872.317238] __x64_sys_quotactl+0x1e/0x30 |
| [ 8872.318266] do_syscall_64+0x46/0x90 |
| [ 8872.319193] entry_SYSCALL_64_after_hwframe+0x44/0xa9 |
| [ 8872.320490] RIP: 0033:0x7f46b5490f2a |
| [ 8872.321414] Code: Bad RIP value. |
| |
| Returning -EAGAIN from xfs_qm_dqpurge() without clearing the |
| XFS_DQ_FREEING flag means the xfs_qm_dqpurge_all() code can never |
| free the dquot, and we loop forever waiting for the XFS_DQ_FREEING |
| flag to go away on the dquot that leaked it via -EAGAIN. |
| |
| Fixes: 8d3d7e2b35ea ("xfs: trylock underlying buffer on dquot flush") |
| Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> |
| Reviewed-by: Allison Collins <allison.henderson@oracle.com> |
| Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com> |
| Reviewed-by: Christoph Hellwig <hch@lst.de> |
| Reviewed-by: Brian Foster <bfoster@redhat.com> |
| Signed-off-by: Dave Chinner <dchinner@redhat.com> |
| Reviewed-by: Dave Chinner <dchinner@redhat.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| fs/xfs/xfs_qm.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c |
| index c225691fad156..2a0cdca80f861 100644 |
| --- a/fs/xfs/xfs_qm.c |
| +++ b/fs/xfs/xfs_qm.c |
| @@ -148,6 +148,7 @@ xfs_qm_dqpurge( |
| error = xfs_bwrite(bp); |
| xfs_buf_relse(bp); |
| } else if (error == -EAGAIN) { |
| + dqp->dq_flags &= ~XFS_DQ_FREEING; |
| goto out_unlock; |
| } |
| xfs_dqflock(dqp); |
| -- |
| 2.25.1 |
| |