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xfs: treat CoW fork operations as delalloc for quota accounting 

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@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong 2018-01-19 09:05:48 -08:00
parent 01c2e13dca
commit 4b4c1326fd
2 changed files with 41 additions and 6 deletions
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32
fs/xfs/libxfs/xfs_bmap.c
View File

@ -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;
}
/*

15
fs/xfs/xfs_reflink.c
View File

@ -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);