[PATCH 2/3] xfs: attach dquots and reserve quota blocks during unwritten conversion

Darrick J. Wong
2019-11-11T01:18:49Z

From: Darrick J. Wong <darrick.wong@oracle.com>

In xfs_iomap_write_unwritten, we need to ensure that dquots are attached
to the inode and quota blocks reserved so that we capture in the quota
counters any blocks allocated to handle a bmbt split. This can happen
on the first unwritten extent conversion to a preallocated sparse file
on a fresh mount.

This was found by running generic/311 with quotas enabled. The bug
seems to have been introduced in "[XFS] rework iocore infrastructure,
remove some code and make it more" from ~2002?

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/xfs_iomap.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index f234929b4f15..97dbe3b2aec0 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -539,6 +539,11 @@ xfs_iomap_write_unwritten(
*/
resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;

+ /* Attach dquots so that bmbt splits are accounted correctly. */
+ error = xfs_qm_dqattach(ip);
+ if (error)
+ return error;
+
do {
/*
* Set up a transaction to convert the range of extents
@@ -557,6 +562,11 @@ xfs_iomap_write_unwritten(
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);

+ error = xfs_trans_reserve_quota_nblks(tp, ip, resblks, 0,
+ XFS_QMOPT_RES_REGBLKS);
+ if (error)
+ goto error_on_bmapi_transaction;
+
/*
* Modify the unwritten extent state of the buffer.
*/