From b8055ed6779d675e30f019ba3b7141848a4d6558 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Thu, 28 Jan 2021 10:56:38 -0800
Subject: [PATCH] xfs: reduce quota reservation when doing a dax unwritten
 extent conversion
Git-commit: b8055ed6779d675e30f019ba3b7141848a4d6558
Patch-mainline: v5.12-rc1
References: git-fixes bsc#1182561

In commit 3b0fe47805802, we reduced the free space requirement to
perform a pre-write unwritten extent conversion on an S_DAX file.  Since
we're not actually allocating any space, the logic goes, we only need
enough reservation to handle shape changes in the bmbt.

The same logic should have been applied to quota -- we're not allocating
any space, so we only need to reserve enough quota to handle the bmbt
shape changes.

Fixes: 3b0fe4780580 ("xfs: Don't use reserved blocks for data blocks with DAX")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
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 8f4b27cded20..b05cfeb09301 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -236,7 +236,7 @@ xfs_iomap_write_direct(
 		bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
 		if (imap->br_state == XFS_EXT_UNWRITTEN) {
 			tflags |= XFS_TRANS_RESERVE;
-			resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
+			resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
 		}
 	}
 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, resrtextents,
-- 
2.30.1