xfs: refactor xfs_bmap_add_extent_delay_real

Use xfs_iext_get_extent to find, and xfs_iext_update_extent to update
entries in the in-core extent list.  This isolates the function from
the detailed layout of the extent list, and generally makes the code
a lot more readable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_bmap.c

@@ -1575,7 +1575,6 @@ xfs_bmap_add_extent_delay_real(
 {
 	struct xfs_bmbt_irec	*new = &bma->got;
 	int			diff;	/* temp value */
-	xfs_bmbt_rec_host_t	*ep;	/* extent entry for idx */
 	int			error;	/* error return value */
 	int			i;	/* temp state */
 	xfs_ifork_t		*ifp;	/* inode fork pointer */
@@ -1587,10 +1586,10 @@ xfs_bmap_add_extent_delay_real(
 	xfs_filblks_t		da_new; /* new count del alloc blocks used */
 	xfs_filblks_t		da_old; /* old count del alloc blocks used */
 	xfs_filblks_t		temp=0;	/* value for da_new calculations */
-	xfs_filblks_t		temp2=0;/* value for da_new calculations */
 	int			tmp_rval;	/* partial logging flags */
 	struct xfs_mount	*mp;
 	xfs_extnum_t		*nextents;
+	struct xfs_bmbt_irec	old;
 
 	mp = bma->ip->i_mount;
 	ifp = XFS_IFORK_PTR(bma->ip, whichfork);
@@ -1616,9 +1615,9 @@ xfs_bmap_add_extent_delay_real(
 	/*
 	 * Set up a bunch of variables to make the tests simpler.
 	 */
-	ep = xfs_iext_get_ext(ifp, bma->idx);
-	xfs_bmbt_get_all(ep, &PREV);
+	xfs_iext_get_extent(ifp, bma->idx, &PREV);
 	new_endoff = new->br_startoff + new->br_blockcount;
+	ASSERT(isnullstartblock(PREV.br_startblock));
 	ASSERT(PREV.br_startoff <= new->br_startoff);
 	ASSERT(PREV.br_startoff + PREV.br_blockcount >= new_endoff);
 
@@ -1693,9 +1692,8 @@ xfs_bmap_add_extent_delay_real(
 		 */
 		bma->idx--;
 		trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
-		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, bma->idx),
-			LEFT.br_blockcount + PREV.br_blockcount +
-			RIGHT.br_blockcount);
+		LEFT.br_blockcount += PREV.br_blockcount + RIGHT.br_blockcount;
+		xfs_iext_update_extent(ifp, bma->idx, &LEFT);
 		trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
 
 		xfs_iext_remove(bma->ip, bma->idx + 1, 2, state);
@@ -1720,9 +1718,7 @@ xfs_bmap_add_extent_delay_real(
 			XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
 			error = xfs_bmbt_update(bma->cur, LEFT.br_startoff,
 					LEFT.br_startblock,
-					LEFT.br_blockcount +
-					PREV.br_blockcount +
-					RIGHT.br_blockcount, LEFT.br_state);
+					LEFT.br_blockcount, LEFT.br_state);
 			if (error)
 				goto done;
 		}
@@ -1735,9 +1731,10 @@ xfs_bmap_add_extent_delay_real(
 		 */
 		bma->idx--;
 
+		old = LEFT;
 		trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
-		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, bma->idx),
-			LEFT.br_blockcount + PREV.br_blockcount);
+		LEFT.br_blockcount += PREV.br_blockcount;
+		xfs_iext_update_extent(ifp, bma->idx, &LEFT);
 		trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
 
 		xfs_iext_remove(bma->ip, bma->idx + 1, 1, state);
@@ -1745,16 +1742,15 @@ xfs_bmap_add_extent_delay_real(
 			rval = XFS_ILOG_DEXT;
 		else {
 			rval = 0;
-			error = xfs_bmbt_lookup_eq(bma->cur, LEFT.br_startoff,
-					LEFT.br_startblock, LEFT.br_blockcount,
+			error = xfs_bmbt_lookup_eq(bma->cur, old.br_startoff,
+					old.br_startblock, old.br_blockcount,
 					&i);
 			if (error)
 				goto done;
 			XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
 			error = xfs_bmbt_update(bma->cur, LEFT.br_startoff,
 					LEFT.br_startblock,
-					LEFT.br_blockcount +
-					PREV.br_blockcount, LEFT.br_state);
+					LEFT.br_blockcount, LEFT.br_state);
 			if (error)
 				goto done;
 		}
@@ -1766,9 +1762,9 @@ xfs_bmap_add_extent_delay_real(
 		 * The right neighbor is contiguous, the left is not.
 		 */
 		trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
-		xfs_bmbt_set_startblock(ep, new->br_startblock);
-		xfs_bmbt_set_blockcount(ep,
-			PREV.br_blockcount + RIGHT.br_blockcount);
+		PREV.br_startblock = new->br_startblock;
+		PREV.br_blockcount += RIGHT.br_blockcount;
+		xfs_iext_update_extent(ifp, bma->idx, &PREV);
 		trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
 
 		xfs_iext_remove(bma->ip, bma->idx + 1, 1, state);
@@ -1783,9 +1779,8 @@ xfs_bmap_add_extent_delay_real(
 				goto done;
 			XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
 			error = xfs_bmbt_update(bma->cur, PREV.br_startoff,
-					new->br_startblock,
-					PREV.br_blockcount +
-					RIGHT.br_blockcount, PREV.br_state);
+					PREV.br_startblock,
+					PREV.br_blockcount, PREV.br_state);
 			if (error)
 				goto done;
 		}
@@ -1798,8 +1793,9 @@ xfs_bmap_add_extent_delay_real(
 		 * the new one.
 		 */
 		trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
-		xfs_bmbt_set_startblock(ep, new->br_startblock);
-		xfs_bmbt_set_state(ep, new->br_state);
+		PREV.br_startblock = new->br_startblock;
+		PREV.br_state = new->br_state;
+		xfs_iext_update_extent(ifp, bma->idx, &PREV);
 		trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
 
 		(*nextents)++;
@@ -1826,38 +1822,39 @@ xfs_bmap_add_extent_delay_real(
 		 * Filling in the first part of a previous delayed allocation.
 		 * The left neighbor is contiguous.
 		 */
+		old = LEFT;
+		temp = PREV.br_blockcount - new->br_blockcount;
+		da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(bma->ip, temp),
+				startblockval(PREV.br_startblock));
+
 		trace_xfs_bmap_pre_update(bma->ip, bma->idx - 1, state, _THIS_IP_);
-		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, bma->idx - 1),
-			LEFT.br_blockcount + new->br_blockcount);
-		xfs_bmbt_set_startoff(ep,
-			PREV.br_startoff + new->br_blockcount);
+		LEFT.br_blockcount += new->br_blockcount;
+		xfs_iext_update_extent(ifp, bma->idx - 1, &LEFT);
 		trace_xfs_bmap_post_update(bma->ip, bma->idx - 1, state, _THIS_IP_);
 
-		temp = PREV.br_blockcount - new->br_blockcount;
 		trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
-		xfs_bmbt_set_blockcount(ep, temp);
+		PREV.br_blockcount = temp = PREV.br_blockcount - new->br_blockcount;
+		PREV.br_startoff += new->br_blockcount;
+		PREV.br_startblock = nullstartblock(da_new);
+		xfs_iext_update_extent(ifp, bma->idx, &PREV);
+		trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
+
 		if (bma->cur == NULL)
 			rval = XFS_ILOG_DEXT;
 		else {
 			rval = 0;
-			error = xfs_bmbt_lookup_eq(bma->cur, LEFT.br_startoff,
-					LEFT.br_startblock, LEFT.br_blockcount,
+			error = xfs_bmbt_lookup_eq(bma->cur, old.br_startoff,
+					old.br_startblock, old.br_blockcount,
 					&i);
 			if (error)
 				goto done;
 			XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
 			error = xfs_bmbt_update(bma->cur, LEFT.br_startoff,
-					LEFT.br_startblock,
-					LEFT.br_blockcount +
-					new->br_blockcount,
+					LEFT.br_startblock, LEFT.br_blockcount,
 					LEFT.br_state);
 			if (error)
 				goto done;
 		}
-		da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(bma->ip, temp),
-			startblockval(PREV.br_startblock));
-		xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
-		trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
 
 		bma->idx--;
 		break;
@@ -1867,10 +1864,6 @@ xfs_bmap_add_extent_delay_real(
 		 * Filling in the first part of a previous delayed allocation.
 		 * The left neighbor is not contiguous.
 		 */
-		trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
-		xfs_bmbt_set_startoff(ep, new_endoff);
-		temp = PREV.br_blockcount - new->br_blockcount;
-		xfs_bmbt_set_blockcount(ep, temp);
 		xfs_iext_insert(bma->ip, bma->idx, 1, new, state);
 		(*nextents)++;
 		if (bma->cur == NULL)
@@ -1898,12 +1891,19 @@ xfs_bmap_add_extent_delay_real(
 			if (error)
 				goto done;
 		}
+
+		temp = PREV.br_blockcount - new->br_blockcount;
 		da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(bma->ip, temp),
 			startblockval(PREV.br_startblock) -
 			(bma->cur ? bma->cur->bc_private.b.allocated : 0));
-		ep = xfs_iext_get_ext(ifp, bma->idx + 1);
-		xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
+
+		trace_xfs_bmap_pre_update(bma->ip, bma->idx + 1, state, _THIS_IP_);
+		PREV.br_startoff = new_endoff;
+		PREV.br_blockcount = temp;
+		PREV.br_startblock = nullstartblock(da_new);
+		xfs_iext_update_extent(ifp, bma->idx + 1, &PREV);
 		trace_xfs_bmap_post_update(bma->ip, bma->idx + 1, state, _THIS_IP_);
+
 		break;
 
 	case BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
@@ -1911,37 +1911,39 @@ xfs_bmap_add_extent_delay_real(
 		 * Filling in the last part of a previous delayed allocation.
 		 * The right neighbor is contiguous with the new allocation.
 		 */
-		temp = PREV.br_blockcount - new->br_blockcount;
+		old = RIGHT;
 		trace_xfs_bmap_pre_update(bma->ip, bma->idx + 1, state, _THIS_IP_);
-		xfs_bmbt_set_blockcount(ep, temp);
-		xfs_bmbt_set_allf(xfs_iext_get_ext(ifp, bma->idx + 1),
-			new->br_startoff, new->br_startblock,
-			new->br_blockcount + RIGHT.br_blockcount,
-			RIGHT.br_state);
+		RIGHT.br_startoff = new->br_startoff;
+		RIGHT.br_startblock = new->br_startblock;
+		RIGHT.br_blockcount += new->br_blockcount;
+		xfs_iext_update_extent(ifp, bma->idx + 1, &RIGHT);
 		trace_xfs_bmap_post_update(bma->ip, bma->idx + 1, state, _THIS_IP_);
+
 		if (bma->cur == NULL)
 			rval = XFS_ILOG_DEXT;
 		else {
 			rval = 0;
-			error = xfs_bmbt_lookup_eq(bma->cur, RIGHT.br_startoff,
-					RIGHT.br_startblock,
-					RIGHT.br_blockcount, &i);
+			error = xfs_bmbt_lookup_eq(bma->cur, old.br_startoff,
+					old.br_startblock,
+					old.br_blockcount, &i);
 			if (error)
 				goto done;
 			XFS_WANT_CORRUPTED_GOTO(mp, i == 1, done);
-			error = xfs_bmbt_update(bma->cur, new->br_startoff,
-					new->br_startblock,
-					new->br_blockcount +
-					RIGHT.br_blockcount,
+			error = xfs_bmbt_update(bma->cur, RIGHT.br_startoff,
+					RIGHT.br_startblock, RIGHT.br_blockcount,
 					RIGHT.br_state);
 			if (error)
 				goto done;
 		}
 
+		temp = PREV.br_blockcount - new->br_blockcount;
 		da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(bma->ip, temp),
 			startblockval(PREV.br_startblock));
+
 		trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
-		xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
+		PREV.br_blockcount = temp;
+		PREV.br_startblock = nullstartblock(da_new);
+		xfs_iext_update_extent(ifp, bma->idx, &PREV);
 		trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
 
 		bma->idx++;
@@ -1952,9 +1954,6 @@ xfs_bmap_add_extent_delay_real(
 		 * Filling in the last part of a previous delayed allocation.
 		 * The right neighbor is not contiguous.
 		 */
-		temp = PREV.br_blockcount - new->br_blockcount;
-		trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
-		xfs_bmbt_set_blockcount(ep, temp);
 		xfs_iext_insert(bma->ip, bma->idx + 1, 1, new, state);
 		(*nextents)++;
 		if (bma->cur == NULL)
@@ -1982,11 +1981,16 @@ xfs_bmap_add_extent_delay_real(
 			if (error)
 				goto done;
 		}
+
+		temp = PREV.br_blockcount - new->br_blockcount;
 		da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(bma->ip, temp),
 			startblockval(PREV.br_startblock) -
 			(bma->cur ? bma->cur->bc_private.b.allocated : 0));
-		ep = xfs_iext_get_ext(ifp, bma->idx);
-		xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
+
+		trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
+		PREV.br_startblock = nullstartblock(da_new);
+		PREV.br_blockcount = temp;
+		xfs_iext_update_extent(ifp, bma->idx, &PREV);
 		trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
 
 		bma->idx++;
@@ -2013,19 +2017,33 @@ xfs_bmap_add_extent_delay_real(
 		 *  PREV @ idx          LEFT              RIGHT
 		 *                      inserted at idx + 1
 		 */
-		temp = new->br_startoff - PREV.br_startoff;
-		temp2 = PREV.br_startoff + PREV.br_blockcount - new_endoff;
-		trace_xfs_bmap_pre_update(bma->ip, bma->idx, 0, _THIS_IP_);
-		xfs_bmbt_set_blockcount(ep, temp);	/* truncate PREV */
+		old = PREV;
+
+		/* LEFT is the new middle */
 		LEFT = *new;
+
+		/* RIGHT is the new right */
 		RIGHT.br_state = PREV.br_state;
-		RIGHT.br_startblock = nullstartblock(
-				(int)xfs_bmap_worst_indlen(bma->ip, temp2));
 		RIGHT.br_startoff = new_endoff;
-		RIGHT.br_blockcount = temp2;
+		RIGHT.br_blockcount =
+			PREV.br_startoff + PREV.br_blockcount - new_endoff;
+		RIGHT.br_startblock =
+			nullstartblock(xfs_bmap_worst_indlen(bma->ip,
+					RIGHT.br_blockcount));
+
+		/* truncate PREV */
+		trace_xfs_bmap_pre_update(bma->ip, bma->idx, 0, _THIS_IP_);
+		PREV.br_blockcount = new->br_startoff - PREV.br_startoff;
+		PREV.br_startblock =
+			nullstartblock(xfs_bmap_worst_indlen(bma->ip,
+					PREV.br_blockcount));
+		xfs_iext_update_extent(ifp, bma->idx, &PREV);
+		trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
+
 		/* insert LEFT (r[0]) and RIGHT (r[1]) at the same time */
 		xfs_iext_insert(bma->ip, bma->idx + 1, 2, &LEFT, state);
 		(*nextents)++;
+
 		if (bma->cur == NULL)
 			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
 		else {
@@ -2051,12 +2069,12 @@ xfs_bmap_add_extent_delay_real(
 			if (error)
 				goto done;
 		}
-		temp = xfs_bmap_worst_indlen(bma->ip, temp);
-		temp2 = xfs_bmap_worst_indlen(bma->ip, temp2);
-		diff = (int)(temp + temp2 -
-			     (startblockval(PREV.br_startblock) -
-			      (bma->cur ?
-			       bma->cur->bc_private.b.allocated : 0)));
+
+		da_new = startblockval(PREV.br_startblock) +
+			 startblockval(RIGHT.br_startblock);
+		diff = da_new - startblockval(old.br_startblock);
+		if (bma->cur)
+			diff += bma->cur->bc_private.b.allocated;
 		if (diff > 0) {
 			error = xfs_mod_fdblocks(bma->ip->i_mount,
 						 -((int64_t)diff), false);
@@ -2065,16 +2083,7 @@ xfs_bmap_add_extent_delay_real(
 				goto done;
 		}
 
-		ep = xfs_iext_get_ext(ifp, bma->idx);
-		xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
-		trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
-		trace_xfs_bmap_pre_update(bma->ip, bma->idx + 2, state, _THIS_IP_);
-		xfs_bmbt_set_startblock(xfs_iext_get_ext(ifp, bma->idx + 2),
-			nullstartblock((int)temp2));
-		trace_xfs_bmap_post_update(bma->ip, bma->idx + 2, state, _THIS_IP_);
-
 		bma->idx++;
-		da_new = temp + temp2;
 		break;
 
 	case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG: