From 1edd2c055dff9710b1e29d4df01902abb0a55f1f Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Sat, 23 May 2020 09:43:30 -0700
Subject: [PATCH] xfs: don't fail unwritten extent conversion on writeback due
 to edquot
Git-commit: 1edd2c055dff9710b1e29d4df01902abb0a55f1f
Patch-mainline: v5.8-rc1
References: bsc#1158242

During writeback, it's possible for the quota block reservation in
xfs_iomap_write_unwritten to fail with EDQUOT because we hit the quota
limit.  This causes writeback errors for data that was already written
to disk, when it's not even guaranteed that the bmbt will expand to
exceed the quota limit.  Irritatingly, this condition is reported to
userspace as EIO by fsync, which is confusing.

We wrote the data, so allow the reservation.  That might put us slightly
above the hard limit, but it's better than losing data after a write.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Anthony Iliopoulos <ailiop@suse.com>

---
 fs/xfs/xfs_iomap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 6ae3a2457777a0..7d8966ce630a8c 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -563,7 +563,7 @@ xfs_iomap_write_unwritten(
 		xfs_trans_ijoin(tp, ip, 0);

 		error = xfs_trans_reserve_quota_nblks(tp, ip, resblks, 0,
-				XFS_QMOPT_RES_REGBLKS);
+				XFS_QMOPT_RES_REGBLKS | XFS_QMOPT_FORCE_RES);
 		if (error)
 			goto error_on_bmapi_transaction;

--
2.27.0