xfs: remove the if_ext_max field in struct xfs_ifork

We spent a lot of effort to maintain this field, but it always equals to the
fork size divided by the constant size of an extent.  The prime use of it is
to assert that the two stay in sync.  Just divide the fork size by the extent
size in the few places that we actually use it and remove the overhead
of maintaining it.  Also introduce a few helpers to consolidate the places
where we actually care about the value.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 47 insertions, 54 deletions

diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index d0ab7883705..7a888ca2f7f 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -249,7 +249,27 @@ xfs_bmbt_lookup_ge(
 }
 
 /*
-* Update the record referred to by cur to the value given
+ * Check if the inode needs to be converted to btree format.
+ */
+static inline bool xfs_bmap_needs_btree(struct xfs_inode *ip, int whichfork)
+{
+	return XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
+		XFS_IFORK_NEXTENTS(ip, whichfork) >
+			XFS_IFORK_MAXEXT(ip, whichfork);
+}
+
+/*
+ * Check if the inode should be converted to extent format.
+ */
+static inline bool xfs_bmap_wants_extents(struct xfs_inode *ip, int whichfork)
+{
+	return XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE &&
+		XFS_IFORK_NEXTENTS(ip, whichfork) <=
+			XFS_IFORK_MAXEXT(ip, whichfork);
+}
+
+/*
+ * Update the record referred to by cur to the value given
  * by [off, bno, len, state].
  * This either works (return 0) or gets an EFSCORRUPTED error.
  */
@@ -683,8 +703,8 @@ xfs_bmap_add_extent_delay_real(
 				goto done;
 			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
 		}
-		if (bma->ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
-		    bma->ip->i_d.di_nextents > bma->ip->i_df.if_ext_max) {
+
+		if (xfs_bmap_needs_btree(bma->ip, XFS_DATA_FORK)) {
 			error = xfs_bmap_extents_to_btree(bma->tp, bma->ip,
 					bma->firstblock, bma->flist,
 					&bma->cur, 1, &tmp_rval, XFS_DATA_FORK);
@@ -767,8 +787,8 @@ xfs_bmap_add_extent_delay_real(
 				goto done;
 			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
 		}
-		if (bma->ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
-		    bma->ip->i_d.di_nextents > bma->ip->i_df.if_ext_max) {
+
+		if (xfs_bmap_needs_btree(bma->ip, XFS_DATA_FORK)) {
 			error = xfs_bmap_extents_to_btree(bma->tp, bma->ip,
 				bma->firstblock, bma->flist, &bma->cur, 1,
 				&tmp_rval, XFS_DATA_FORK);
@@ -836,8 +856,8 @@ xfs_bmap_add_extent_delay_real(
 				goto done;
 			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
 		}
-		if (bma->ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
-		    bma->ip->i_d.di_nextents > bma->ip->i_df.if_ext_max) {
+
+		if (xfs_bmap_needs_btree(bma->ip, XFS_DATA_FORK)) {
 			error = xfs_bmap_extents_to_btree(bma->tp, bma->ip,
 					bma->firstblock, bma->flist, &bma->cur,
 					1, &tmp_rval, XFS_DATA_FORK);
@@ -884,8 +904,7 @@ xfs_bmap_add_extent_delay_real(
 	}
 
 	/* convert to a btree if necessary */
-	if (XFS_IFORK_FORMAT(bma->ip, XFS_DATA_FORK) == XFS_DINODE_FMT_EXTENTS &&
-	    XFS_IFORK_NEXTENTS(bma->ip, XFS_DATA_FORK) > ifp->if_ext_max) {
+	if (xfs_bmap_needs_btree(bma->ip, XFS_DATA_FORK)) {
 		int	tmp_logflags;	/* partial log flag return val */
 
 		ASSERT(bma->cur == NULL);
@@ -1421,8 +1440,7 @@ xfs_bmap_add_extent_unwritten_real(
 	}
 
 	/* convert to a btree if necessary */
-	if (XFS_IFORK_FORMAT(ip, XFS_DATA_FORK) == XFS_DINODE_FMT_EXTENTS &&
-	    XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) > ifp->if_ext_max) {
+	if (xfs_bmap_needs_btree(ip, XFS_DATA_FORK)) {
 		int	tmp_logflags;	/* partial log flag return val */
 
 		ASSERT(cur == NULL);
@@ -1812,8 +1830,7 @@ xfs_bmap_add_extent_hole_real(
 	}
 
 	/* convert to a btree if necessary */
-	if (XFS_IFORK_FORMAT(bma->ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
-	    XFS_IFORK_NEXTENTS(bma->ip, whichfork) > ifp->if_ext_max) {
+	if (xfs_bmap_needs_btree(bma->ip, whichfork)) {
 		int	tmp_logflags;	/* partial log flag return val */
 
 		ASSERT(bma->cur == NULL);
@@ -3037,8 +3054,7 @@ xfs_bmap_extents_to_btree(
 
 	ifp = XFS_IFORK_PTR(ip, whichfork);
 	ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS);
-	ASSERT(ifp->if_ext_max ==
-	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
+
 	/*
 	 * Make space in the inode incore.
 	 */
@@ -3184,13 +3200,8 @@ xfs_bmap_forkoff_reset(
 	    ip->i_d.di_format != XFS_DINODE_FMT_BTREE) {
 		uint	dfl_forkoff = xfs_default_attroffset(ip) >> 3;
 
-		if (dfl_forkoff > ip->i_d.di_forkoff) {
+		if (dfl_forkoff > ip->i_d.di_forkoff)
 			ip->i_d.di_forkoff = dfl_forkoff;
-			ip->i_df.if_ext_max =
-				XFS_IFORK_DSIZE(ip) / sizeof(xfs_bmbt_rec_t);
-			ip->i_afp->if_ext_max =
-				XFS_IFORK_ASIZE(ip) / sizeof(xfs_bmbt_rec_t);
-		}
 	}
 }
 
@@ -3430,8 +3441,6 @@ xfs_bmap_add_attrfork(
 	int			error;		/* error return value */
 
 	ASSERT(XFS_IFORK_Q(ip) == 0);
-	ASSERT(ip->i_df.if_ext_max ==
-	       XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t));
 
 	mp = ip->i_mount;
 	ASSERT(!XFS_NOT_DQATTACHED(mp, ip));
@@ -3486,12 +3495,9 @@ xfs_bmap_add_attrfork(
 		error = XFS_ERROR(EINVAL);
 		goto error1;
 	}
-	ip->i_df.if_ext_max =
-		XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t);
+
 	ASSERT(ip->i_afp == NULL);
 	ip->i_afp = kmem_zone_zalloc(xfs_ifork_zone, KM_SLEEP);
-	ip->i_afp->if_ext_max =
-		XFS_IFORK_ASIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t);
 	ip->i_afp->if_flags = XFS_IFEXTENTS;
 	logflags = 0;
 	xfs_bmap_init(&flist, &firstblock);
@@ -3535,20 +3541,17 @@ xfs_bmap_add_attrfork(
 		} else
 			spin_unlock(&mp->m_sb_lock);
 	}
-	if ((error = xfs_bmap_finish(&tp, &flist, &committed)))
+
+	error = xfs_bmap_finish(&tp, &flist, &committed);
+	if (error)
 		goto error2;
-	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
-	ASSERT(ip->i_df.if_ext_max ==
-	       XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t));
-	return error;
+	return xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 error2:
 	xfs_bmap_cancel(&flist);
 error1:
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 error0:
 	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
-	ASSERT(ip->i_df.if_ext_max ==
-	       XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t));
 	return error;
 }
 
@@ -4379,8 +4382,6 @@ xfs_bmapi_read(
 	XFS_STATS_INC(xs_blk_mapr);
 
 	ifp = XFS_IFORK_PTR(ip, whichfork);
-	ASSERT(ifp->if_ext_max ==
-	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
 
 	if (!(ifp->if_flags & XFS_IFEXTENTS)) {
 		error = xfs_iread_extents(NULL, ip, whichfork);
@@ -4871,8 +4872,6 @@ xfs_bmapi_write(
 		return XFS_ERROR(EIO);
 
 	ifp = XFS_IFORK_PTR(ip, whichfork);
-	ASSERT(ifp->if_ext_max ==
-	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
 
 	XFS_STATS_INC(xs_blk_mapw);
 
@@ -4981,8 +4980,7 @@ xfs_bmapi_write(
 	/*
 	 * Transform from btree to extents, give it cur.
 	 */
-	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE &&
-	    XFS_IFORK_NEXTENTS(ip, whichfork) <= ifp->if_ext_max) {
+	if (xfs_bmap_wants_extents(ip, whichfork)) {
 		int		tmp_logflags = 0;
 
 		ASSERT(bma.cur);
@@ -4992,10 +4990,10 @@ xfs_bmapi_write(
 		if (error)
 			goto error0;
 	}
-	ASSERT(ifp->if_ext_max ==
-	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
+
 	ASSERT(XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE ||
-	       XFS_IFORK_NEXTENTS(ip, whichfork) > ifp->if_ext_max);
+	       XFS_IFORK_NEXTENTS(ip, whichfork) >
+		XFS_IFORK_MAXEXT(ip, whichfork));
 	error = 0;
 error0:
 	/*
@@ -5095,8 +5093,7 @@ xfs_bunmapi(
 
 	ASSERT(len > 0);
 	ASSERT(nexts >= 0);
-	ASSERT(ifp->if_ext_max ==
-	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
+
 	if (!(ifp->if_flags & XFS_IFEXTENTS) &&
 	    (error = xfs_iread_extents(tp, ip, whichfork)))
 		return error;
@@ -5322,7 +5319,8 @@ xfs_bunmapi(
 		 */
 		if (!wasdel && xfs_trans_get_block_res(tp) == 0 &&
 		    XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
-		    XFS_IFORK_NEXTENTS(ip, whichfork) >= ifp->if_ext_max &&
+		    XFS_IFORK_NEXTENTS(ip, whichfork) >= /* Note the >= */
+			XFS_IFORK_MAXEXT(ip, whichfork) &&
 		    del.br_startoff > got.br_startoff &&
 		    del.br_startoff + del.br_blockcount <
 		    got.br_startoff + got.br_blockcount) {
@@ -5353,13 +5351,11 @@ nodelete:
 		}
 	}
 	*done = bno == (xfs_fileoff_t)-1 || bno < start || lastx < 0;
-	ASSERT(ifp->if_ext_max ==
-	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
+
 	/*
 	 * Convert to a btree if necessary.
 	 */
-	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
-	    XFS_IFORK_NEXTENTS(ip, whichfork) > ifp->if_ext_max) {
+	if (xfs_bmap_needs_btree(ip, whichfork)) {
 		ASSERT(cur == NULL);
 		error = xfs_bmap_extents_to_btree(tp, ip, firstblock, flist,
 			&cur, 0, &tmp_logflags, whichfork);
@@ -5370,8 +5366,7 @@ nodelete:
 	/*
 	 * transform from btree to extents, give it cur
 	 */
-	else if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE &&
-		 XFS_IFORK_NEXTENTS(ip, whichfork) <= ifp->if_ext_max) {
+	else if (xfs_bmap_wants_extents(ip, whichfork)) {
 		ASSERT(cur != NULL);
 		error = xfs_bmap_btree_to_extents(tp, ip, cur, &tmp_logflags,
 			whichfork);
@@ -5382,8 +5377,6 @@ nodelete:
 	/*
 	 * transform from extents to local?
 	 */
-	ASSERT(ifp->if_ext_max ==
-	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
 	error = 0;
 error0:
 	/*