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Commit 4b4c1326 authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

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: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 01c2e13d

fs/xfs/libxfs/xfs_bmap.c

+30 −2
Original line number Diff line number Diff line
@@ -3343,7 +3343,34 @@ xfs_bmap_btalloc_accounting( 
	struct xfs_bmalloca	*ap,

	struct xfs_alloc_arg	*args)

{

	if (!(ap->flags & XFS_BMAPI_COWFORK))

	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)
@@ -4820,6 +4847,7 @@ xfs_bmap_del_extent_cow( 
		xfs_iext_insert(ip, icur, &new, state);

		break;

	}

	ip->i_delayed_blks -= del->br_blockcount;

}



/*

fs/xfs/xfs_reflink.c

+11 −4
Original line number Diff line number Diff line
@@ -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);