From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Since the CoW fork only exists in memory, it is incorrect to update the
on-disk quota block counts when we modify the CoW fork. Unlike the data
fork, even real extents in the CoW fork are only delalloc-style
reservations (on-disk they're owned by the refcountbt) so they must not
be tracked in the on disk quota info. Ensure the i_delayed_blks
accounting reflects this too.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_bmap.c | 32 ++++++++++++++++++++++++++++++--
fs/xfs/xfs_reflink.c | 15 +++++++++++----
2 files changed, 41 insertions(+), 6 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 4582f55..cad21fd 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3343,8 +3343,35 @@ xfs_bmap_btalloc_accounting(
struct xfs_bmalloca *ap,
struct xfs_alloc_arg *args)
{
- if (!(ap->flags & XFS_BMAPI_COWFORK))
- ap->ip->i_d.di_nblocks += args->len;
+ if (ap->flags & XFS_BMAPI_COWFORK) {
+ /*
+ * COW fork blocks are in-core only and thus are treated as
+ * in-core quota reservation (like delalloc blocks) even when
+ * converted to real blocks. The quota reservation is not
+ * accounted to disk until blocks are remapped to the data
+ * fork. So if these blocks were previously delalloc, we
+ * already have quota reservation and there's nothing to do
+ * yet.
+ */
+ if (ap->wasdel)
+ return;
+
+ /*
+ * Otherwise, we've allocated blocks in a hole. The transaction
+ * has acquired in-core quota reservation for this extent.
+ * Rather than account these as real blocks, however, we reduce
+ * the transaction quota reservation based on the allocation.
+ * This essentially transfers the transaction quota reservation
+ * to that of a delalloc extent.
+ */
+ ap->ip->i_delayed_blks += args->len;
+ xfs_trans_mod_dquot_byino(ap->tp, ap->ip, XFS_TRANS_DQ_RES_BLKS,
+ -(long)args->len);
+ return;
+ }
+
+ /* data/attr fork only */
+ ap->ip->i_d.di_nblocks += args->len;
xfs_trans_log_inode(ap->tp, ap->ip, XFS_ILOG_CORE);
if (ap->wasdel)
ap->ip->i_delayed_blks -= args->len;
@@ -4820,6 +4847,7 @@ xfs_bmap_del_extent_cow(
xfs_iext_insert(ip, icur, &new, state);
break;
}
+ ip->i_delayed_blks -= del->br_blockcount;
}
/*
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 85a119e..c4f0aff 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -599,10 +599,6 @@ xfs_reflink_cancel_cow_blocks(
del.br_startblock, del.br_blockcount,
NULL);
- /* Update quota accounting */
- xfs_trans_mod_dquot_byino(*tpp, ip, XFS_TRANS_DQ_BCOUNT,
- -(long)del.br_blockcount);
-
/* Roll the transaction */
xfs_defer_ijoin(&dfops, ip);
error = xfs_defer_finish(tpp, &dfops);
@@ -613,6 +609,13 @@ xfs_reflink_cancel_cow_blocks(
/* Remove the mapping from the CoW fork. */
xfs_bmap_del_extent_cow(ip, &icur, &got, &del);
+
+ /* Remove the quota reservation */
+ error = xfs_trans_reserve_quota_nblks(NULL, ip,
+ -(long)del.br_blockcount, 0,
+ XFS_QMOPT_RES_REGBLKS);
+ if (error)
+ break;
} else {
/* Didn't do anything, push cursor back. */
xfs_iext_prev(ifp, &icur);
@@ -795,6 +798,10 @@ xfs_reflink_end_cow(
if (error)
goto out_defer;
+ /* Charge this new data fork mapping to the on-disk quota. */
+ xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_DELBCOUNT,
+ (long)del.br_blockcount);
+
/* Remove the mapping from the CoW fork. */
xfs_bmap_del_extent_cow(ip, &icur, &got, &del);
--
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