xfs: Define max extent length based on on-disk format definition

The maximum extent length depends on maximum block count that can be stored in
a BMBT record. Hence this commit defines MAXEXTLEN based on
BMBT_BLOCKCOUNT_BITLEN.

While at it, the commit also renames MAXEXTLEN to XFS_MAX_BMBT_EXTLEN.

Suggested-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>

1 files changed, 29 insertions, 28 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 74198dd82b03..00b8e6e1c404 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -1452,7 +1452,7 @@ xfs_bmap_add_extent_delay_real(
 	    LEFT.br_startoff + LEFT.br_blockcount == new->br_startoff &&
 	    LEFT.br_startblock + LEFT.br_blockcount == new->br_startblock &&
 	    LEFT.br_state == new->br_state &&
-	    LEFT.br_blockcount + new->br_blockcount <= MAXEXTLEN)
+	    LEFT.br_blockcount + new->br_blockcount <= XFS_MAX_BMBT_EXTLEN)
 		state |= BMAP_LEFT_CONTIG;
 
 	/*
@@ -1470,13 +1470,13 @@ xfs_bmap_add_extent_delay_real(
 	    new_endoff == RIGHT.br_startoff &&
 	    new->br_startblock + new->br_blockcount == RIGHT.br_startblock &&
 	    new->br_state == RIGHT.br_state &&
-	    new->br_blockcount + RIGHT.br_blockcount <= MAXEXTLEN &&
+	    new->br_blockcount + RIGHT.br_blockcount <= XFS_MAX_BMBT_EXTLEN &&
 	    ((state & (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
 		       BMAP_RIGHT_FILLING)) !=
 		      (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
 		       BMAP_RIGHT_FILLING) ||
 	     LEFT.br_blockcount + new->br_blockcount + RIGHT.br_blockcount
-			<= MAXEXTLEN))
+			<= XFS_MAX_BMBT_EXTLEN))
 		state |= BMAP_RIGHT_CONTIG;
 
 	error = 0;
@@ -2000,7 +2000,7 @@ xfs_bmap_add_extent_unwritten_real(
 	    LEFT.br_startoff + LEFT.br_blockcount == new->br_startoff &&
 	    LEFT.br_startblock + LEFT.br_blockcount == new->br_startblock &&
 	    LEFT.br_state == new->br_state &&
-	    LEFT.br_blockcount + new->br_blockcount <= MAXEXTLEN)
+	    LEFT.br_blockcount + new->br_blockcount <= XFS_MAX_BMBT_EXTLEN)
 		state |= BMAP_LEFT_CONTIG;
 
 	/*
@@ -2018,13 +2018,13 @@ xfs_bmap_add_extent_unwritten_real(
 	    new_endoff == RIGHT.br_startoff &&
 	    new->br_startblock + new->br_blockcount == RIGHT.br_startblock &&
 	    new->br_state == RIGHT.br_state &&
-	    new->br_blockcount + RIGHT.br_blockcount <= MAXEXTLEN &&
+	    new->br_blockcount + RIGHT.br_blockcount <= XFS_MAX_BMBT_EXTLEN &&
 	    ((state & (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
 		       BMAP_RIGHT_FILLING)) !=
 		      (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
 		       BMAP_RIGHT_FILLING) ||
 	     LEFT.br_blockcount + new->br_blockcount + RIGHT.br_blockcount
-			<= MAXEXTLEN))
+			<= XFS_MAX_BMBT_EXTLEN))
 		state |= BMAP_RIGHT_CONTIG;
 
 	/*
@@ -2510,15 +2510,15 @@ xfs_bmap_add_extent_hole_delay(
 	 */
 	if ((state & BMAP_LEFT_VALID) && (state & BMAP_LEFT_DELAY) &&
 	    left.br_startoff + left.br_blockcount == new->br_startoff &&
-	    left.br_blockcount + new->br_blockcount <= MAXEXTLEN)
+	    left.br_blockcount + new->br_blockcount <= XFS_MAX_BMBT_EXTLEN)
 		state |= BMAP_LEFT_CONTIG;
 
 	if ((state & BMAP_RIGHT_VALID) && (state & BMAP_RIGHT_DELAY) &&
 	    new->br_startoff + new->br_blockcount == right.br_startoff &&
-	    new->br_blockcount + right.br_blockcount <= MAXEXTLEN &&
+	    new->br_blockcount + right.br_blockcount <= XFS_MAX_BMBT_EXTLEN &&
 	    (!(state & BMAP_LEFT_CONTIG) ||
 	     (left.br_blockcount + new->br_blockcount +
-	      right.br_blockcount <= MAXEXTLEN)))
+	      right.br_blockcount <= XFS_MAX_BMBT_EXTLEN)))
 		state |= BMAP_RIGHT_CONTIG;
 
 	/*
@@ -2661,17 +2661,17 @@ xfs_bmap_add_extent_hole_real(
 	    left.br_startoff + left.br_blockcount == new->br_startoff &&
 	    left.br_startblock + left.br_blockcount == new->br_startblock &&
 	    left.br_state == new->br_state &&
-	    left.br_blockcount + new->br_blockcount <= MAXEXTLEN)
+	    left.br_blockcount + new->br_blockcount <= XFS_MAX_BMBT_EXTLEN)
 		state |= BMAP_LEFT_CONTIG;
 
 	if ((state & BMAP_RIGHT_VALID) && !(state & BMAP_RIGHT_DELAY) &&
 	    new->br_startoff + new->br_blockcount == right.br_startoff &&
 	    new->br_startblock + new->br_blockcount == right.br_startblock &&
 	    new->br_state == right.br_state &&
-	    new->br_blockcount + right.br_blockcount <= MAXEXTLEN &&
+	    new->br_blockcount + right.br_blockcount <= XFS_MAX_BMBT_EXTLEN &&
 	    (!(state & BMAP_LEFT_CONTIG) ||
 	     left.br_blockcount + new->br_blockcount +
-	     right.br_blockcount <= MAXEXTLEN))
+	     right.br_blockcount <= XFS_MAX_BMBT_EXTLEN))
 		state |= BMAP_RIGHT_CONTIG;
 
 	error = 0;
@@ -2906,15 +2906,15 @@ xfs_bmap_extsize_align(
 
 	/*
 	 * For large extent hint sizes, the aligned extent might be larger than
-	 * MAXEXTLEN. In that case, reduce the size by an extsz so that it pulls
-	 * the length back under MAXEXTLEN. The outer allocation loops handle
-	 * short allocation just fine, so it is safe to do this. We only want to
-	 * do it when we are forced to, though, because it means more allocation
-	 * operations are required.
+	 * XFS_BMBT_MAX_EXTLEN. In that case, reduce the size by an extsz so
+	 * that it pulls the length back under XFS_BMBT_MAX_EXTLEN. The outer
+	 * allocation loops handle short allocation just fine, so it is safe to
+	 * do this. We only want to do it when we are forced to, though, because
+	 * it means more allocation operations are required.
 	 */
-	while (align_alen > MAXEXTLEN)
+	while (align_alen > XFS_MAX_BMBT_EXTLEN)
 		align_alen -= extsz;
-	ASSERT(align_alen <= MAXEXTLEN);
+	ASSERT(align_alen <= XFS_MAX_BMBT_EXTLEN);
 
 	/*
 	 * If the previous block overlaps with this proposed allocation
@@ -3004,9 +3004,9 @@ xfs_bmap_extsize_align(
 			return -EINVAL;
 	} else {
 		ASSERT(orig_off >= align_off);
-		/* see MAXEXTLEN handling above */
+		/* see XFS_BMBT_MAX_EXTLEN handling above */
 		ASSERT(orig_end <= align_off + align_alen ||
-		       align_alen + extsz > MAXEXTLEN);
+		       align_alen + extsz > XFS_MAX_BMBT_EXTLEN);
 	}
 
 #ifdef DEBUG
@@ -3971,7 +3971,7 @@ xfs_bmapi_reserve_delalloc(
 	 * Cap the alloc length. Keep track of prealloc so we know whether to
 	 * tag the inode before we return.
 	 */
-	alen = XFS_FILBLKS_MIN(len + prealloc, MAXEXTLEN);
+	alen = XFS_FILBLKS_MIN(len + prealloc, XFS_MAX_BMBT_EXTLEN);
 	if (!eof)
 		alen = XFS_FILBLKS_MIN(alen, got->br_startoff - aoff);
 	if (prealloc && alen >= len)
@@ -4104,7 +4104,7 @@ xfs_bmapi_allocate(
 		if (!xfs_iext_peek_prev_extent(ifp, &bma->icur, &bma->prev))
 			bma->prev.br_startoff = NULLFILEOFF;
 	} else {
-		bma->length = XFS_FILBLKS_MIN(bma->length, MAXEXTLEN);
+		bma->length = XFS_FILBLKS_MIN(bma->length, XFS_MAX_BMBT_EXTLEN);
 		if (!bma->eof)
 			bma->length = XFS_FILBLKS_MIN(bma->length,
 					bma->got.br_startoff - bma->offset);
@@ -4424,8 +4424,8 @@ xfs_bmapi_write(
 			 * xfs_extlen_t and therefore 32 bits. Hence we have to
 			 * check for 32-bit overflows and handle them here.
 			 */
-			if (len > (xfs_filblks_t)MAXEXTLEN)
-				bma.length = MAXEXTLEN;
+			if (len > (xfs_filblks_t)XFS_MAX_BMBT_EXTLEN)
+				bma.length = XFS_MAX_BMBT_EXTLEN;
 			else
 				bma.length = len;
 
@@ -4560,7 +4560,8 @@ xfs_bmapi_convert_delalloc(
 	bma.ip = ip;
 	bma.wasdel = true;
 	bma.offset = bma.got.br_startoff;
-	bma.length = max_t(xfs_filblks_t, bma.got.br_blockcount, MAXEXTLEN);
+	bma.length = max_t(xfs_filblks_t, bma.got.br_blockcount,
+			XFS_MAX_BMBT_EXTLEN);
 	bma.minleft = xfs_bmapi_minleft(tp, ip, whichfork);
 
 	/*
@@ -4641,7 +4642,7 @@ xfs_bmapi_remap(
 
 	ifp = XFS_IFORK_PTR(ip, whichfork);
 	ASSERT(len > 0);
-	ASSERT(len <= (xfs_filblks_t)MAXEXTLEN);
+	ASSERT(len <= (xfs_filblks_t)XFS_MAX_BMBT_EXTLEN);
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 	ASSERT(!(flags & ~(XFS_BMAPI_ATTRFORK | XFS_BMAPI_PREALLOC |
 			   XFS_BMAPI_NORMAP)));
@@ -5641,7 +5642,7 @@ xfs_bmse_can_merge(
 	if ((left->br_startoff + left->br_blockcount != startoff) ||
 	    (left->br_startblock + left->br_blockcount != got->br_startblock) ||
 	    (left->br_state != got->br_state) ||
-	    (left->br_blockcount + got->br_blockcount > MAXEXTLEN))
+	    (left->br_blockcount + got->br_blockcount > XFS_MAX_BMBT_EXTLEN))
 		return false;
 
 	return true;