xfs: refactor delalloc indlen reservation split into helper (a9bd24ac) · Commits · 戴 / test

fs/xfs/libxfs/xfs_bmap.c

+54 −19

Original line number	Diff line number	Diff line
		@@ -4720,6 +4720,47 @@ error0:
		return error;
		}

		/*
		* When a delalloc extent is split (e.g., due to a hole punch), the original
		* indlen reservation must be shared across the two new extents that are left
		* behind.
		*
		* Given the original reservation and the worst case indlen for the two new
		* extents (as calculated by xfs_bmap_worst_indlen()), split the original
		* reservation fairly across the two new extents.
		*/
		static void
		xfs_bmap_split_indlen(
		xfs_filblks_t ores, /* original res. */
		xfs_filblks_t indlen1, / ext1 worst indlen */
		xfs_filblks_t indlen2) / ext2 worst indlen */
		{
		xfs_filblks_t len1 = *indlen1;
		xfs_filblks_t len2 = *indlen2;
		xfs_filblks_t nres = len1 + len2; /* new total res. */

		/*
		* The only blocks available are those reserved for the original extent.
		* Therefore, we have to skim blocks off each of the new reservations so
		* long as the new total reservation is greater than the original.
		*/
		while (nres > ores) {
		if (len1) {
		len1--;
		nres--;
		}
		if (nres == ores)
		break;
		if (len2) {
		len2--;
		nres--;
		}
		}

		*indlen1 = len1;
		*indlen2 = len2;
		}

		/*
		* Called by xfs_bmapi to update file extent records and the btree
		* after removing space (or undoing a delayed allocation).
		@@ -4985,27 +5026,21 @@ xfs_bmap_del_extent(
		XFS_IFORK_NEXTENTS(ip, whichfork) + 1);
		} else {
		ASSERT(whichfork == XFS_DATA_FORK);
		temp = xfs_bmap_worst_indlen(ip, temp);

		/*
		* Distribute the original indlen reservation across the
		* two new extents.
		*/
		temp = xfs_bmap_worst_indlen(ip, got.br_blockcount);
		temp2 = xfs_bmap_worst_indlen(ip, new.br_blockcount);
		xfs_bmap_split_indlen(da_old, &temp, &temp2);
		da_new = temp + temp2;

		/*
		* Set the reservation for each extent.
		*/
		xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
		temp2 = xfs_bmap_worst_indlen(ip, temp2);
		new.br_startblock = nullstartblock((int)temp2);
		da_new = temp + temp2;
		while (da_new > da_old) {
		if (temp) {
		temp--;
		da_new--;
		xfs_bmbt_set_startblock(ep,
		nullstartblock((int)temp));
		}
		if (da_new == da_old)
		break;
		if (temp2) {
		temp2--;
		da_new--;
		new.br_startblock =
		nullstartblock((int)temp2);
		}
		}
		}
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
		xfs_iext_insert(ip, *idx + 1, 1, &new, state);

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