[PATCH 09/13] xfs: refactor reflink functions to use xfs_trans_alloc_inode

Darrick J. Wong
2021-01-28T06:02:57Z

From: Darrick J. Wong <djwong@kernel.org>

The two remaining callers of xfs_trans_reserve_quota_nblks are in the
reflink code. These conversions aren't as uniform as the previous
conversions, so call that out in a separate patch.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/xfs_reflink.c | 58 +++++++++++++++++++++-----------------------------
1 file changed, 24 insertions(+), 34 deletions(-)

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 0778b5810c26..ded86cc4764c 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -376,16 +376,15 @@ xfs_reflink_allocate_cow(
resblks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);

xfs_iunlock(ip, *lockmode);
- error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
- *lockmode = XFS_ILOCK_EXCL;
- xfs_ilock(ip, *lockmode);

- if (error)
+ error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
+ false, &tp);
+ if (error) {
+ /* This function must return with ILOCK_EXCL held. */
+ *lockmode = XFS_ILOCK_EXCL;
+ xfs_ilock(ip, *lockmode);
return error;
-
- error = xfs_qm_dqattach_locked(ip, false);
- if (error)
- goto out_trans_cancel;
+ }

/*
* Check for an overlapping extent again now that we dropped the ilock.
@@ -398,12 +397,6 @@ xfs_reflink_allocate_cow(
goto convert;
}

- error = xfs_trans_reserve_quota_nblks(tp, ip, resblks, 0, false);
- if (error)
- goto out_trans_cancel;
-
- xfs_trans_ijoin(tp, ip, 0);
-
/* Allocate the entire reservation as unwritten blocks. */
nimaps = 1;
error = xfs_bmapi_write(tp, ip, imap->br_startoff, imap->br_blockcount,
@@ -997,7 +990,7 @@ xfs_reflink_remap_extent(
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
xfs_off_t newlen;
- int64_t qres, qdelta;
+ int64_t qdelta = 0;
unsigned int resblks;
bool smap_real;
bool dmap_written = xfs_bmap_is_written_extent(dmap);
@@ -1005,15 +998,22 @@ xfs_reflink_remap_extent(
int nimaps;
int error;

- /* Start a rolling transaction to switch the mappings */
+ /*
+ * Start a rolling transaction to switch the mappings.
+ *
+ * Adding a written extent to the extent map can cause a bmbt split,
+ * and removing a mapped extent from the extent can cause a bmbt split.
+ * The two operations cannot both cause a split since they operate on
+ * the same index in the bmap btree, so we only need a reservation for
+ * one bmbt split if either thing is happening. However, we haven't
+ * locked the inode yet, so we reserve assuming this is the case.
+ */
resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
- error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
+ error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
+ false, &tp);
if (error)
goto out;

- xfs_ilock(ip, XFS_ILOCK_EXCL);
- xfs_trans_ijoin(tp, ip, 0);
-
/*
* Read what's currently mapped in the destination file into smap.
* If smap isn't a hole, we will have to remove it before we can add
@@ -1061,15 +1061,9 @@ xfs_reflink_remap_extent(
}

/*
- * Compute quota reservation if we think the quota block counter for
+ * Increase quota reservation if we think the quota block counter for
* this file could increase.
*
- * Adding a written extent to the extent map can cause a bmbt split,
- * and removing a mapped extent from the extent can cause a bmbt split.
- * The two operations cannot both cause a split since they operate on
- * the same index in the bmap btree, so we only need a reservation for
- * one bmbt split if either thing is happening.
- *
* If we are mapping a written extent into the file, we need to have
* enough quota block count reservation to handle the blocks in that
* extent. We log only the delta to the quota block counts, so if the
@@ -1083,13 +1077,9 @@ xfs_reflink_remap_extent(
* before we started. That should have removed all the delalloc
* reservations, but we code defensively.
*/
- qres = qdelta = 0;
- if (smap_real || dmap_written)
- qres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
- if (!smap_real && dmap_written)
- qres += dmap->br_blockcount;
- if (qres > 0) {
- error = xfs_trans_reserve_quota_nblks(tp, ip, qres, 0, false);
+ if (!smap_real && dmap_written) {
+ error = xfs_trans_reserve_quota_nblks(tp, ip,
+ dmap->br_blockcount, 0, false);
if (error)
goto out_cancel;
}