1 files changed, 121 insertions, 22 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap_btree.c b/fs/xfs/libxfs/xfs_bmap_btree.c
index 3464be771f95..188feac04b60 100644
--- a/fs/xfs/libxfs/xfs_bmap_btree.c
+++ b/fs/xfs/libxfs/xfs_bmap_btree.c
@@ -369,38 +369,26 @@ xfs_bmbt_init_rec_from_cur(
 	xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
 }
 
-STATIC int64_t
-xfs_bmbt_key_diff(
+STATIC int
+xfs_bmbt_cmp_key_with_cur(
 	struct xfs_btree_cur		*cur,
 	const union xfs_btree_key	*key)
 {
-	return (int64_t)be64_to_cpu(key->bmbt.br_startoff) -
-				      cur->bc_rec.b.br_startoff;
+	return cmp_int(be64_to_cpu(key->bmbt.br_startoff),
+		       cur->bc_rec.b.br_startoff);
 }
 
-STATIC int64_t
-xfs_bmbt_diff_two_keys(
+STATIC int
+xfs_bmbt_cmp_two_keys(
 	struct xfs_btree_cur		*cur,
 	const union xfs_btree_key	*k1,
 	const union xfs_btree_key	*k2,
 	const union xfs_btree_key	*mask)
 {
-	uint64_t			a = be64_to_cpu(k1->bmbt.br_startoff);
-	uint64_t			b = be64_to_cpu(k2->bmbt.br_startoff);
-
 	ASSERT(!mask || mask->bmbt.br_startoff);
 
-	/*
-	 * Note: This routine previously casted a and b to int64 and subtracted
-	 * them to generate a result.  This lead to problems if b was the
-	 * "maximum" key value (all ones) being signed incorrectly, hence this
-	 * somewhat less efficient version.
-	 */
-	if (a > b)
-		return 1;
-	if (b > a)
-		return -1;
-	return 0;
+	return cmp_int(be64_to_cpu(k1->bmbt.br_startoff),
+		       be64_to_cpu(k2->bmbt.br_startoff));
 }
 
 static xfs_failaddr_t
@@ -516,6 +504,116 @@ xfs_bmbt_keys_contiguous(
 				 be64_to_cpu(key2->bmbt.br_startoff));
 }
 
+static inline void
+xfs_bmbt_move_ptrs(
+	struct xfs_mount	*mp,
+	struct xfs_btree_block	*broot,
+	short			old_size,
+	size_t			new_size,
+	unsigned int		numrecs)
+{
+	void			*dptr;
+	void			*sptr;
+
+	sptr = xfs_bmap_broot_ptr_addr(mp, broot, 1, old_size);
+	dptr = xfs_bmap_broot_ptr_addr(mp, broot, 1, new_size);
+	memmove(dptr, sptr, numrecs * sizeof(xfs_bmbt_ptr_t));
+}
+
+/*
+ * Reallocate the space for if_broot based on the number of records.  Move the
+ * records and pointers in if_broot to fit the new size.  When shrinking this
+ * will eliminate holes between the records and pointers created by the caller.
+ * When growing this will create holes to be filled in by the caller.
+ *
+ * The caller must not request to add more records than would fit in the
+ * on-disk inode root.  If the if_broot is currently NULL, then if we are
+ * adding records, one will be allocated.  The caller must also not request
+ * that the number of records go below zero, although it can go to zero.
+ *
+ * ip -- the inode whose if_broot area is changing
+ * whichfork -- which inode fork to change
+ * new_numrecs -- the new number of records requested for the if_broot array
+ *
+ * Returns the incore btree root block.
+ */
+struct xfs_btree_block *
+xfs_bmap_broot_realloc(
+	struct xfs_inode	*ip,
+	int			whichfork,
+	unsigned int		new_numrecs)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
+	struct xfs_btree_block	*broot;
+	unsigned int		new_size;
+	unsigned int		old_size = ifp->if_broot_bytes;
+
+	/*
+	 * Block mapping btrees do not support storing zero records; if this
+	 * happens, the fork is being changed to FMT_EXTENTS.  Free the broot
+	 * and get out.
+	 */
+	if (new_numrecs == 0)
+		return xfs_broot_realloc(ifp, 0);
+
+	new_size = xfs_bmap_broot_space_calc(mp, new_numrecs);
+
+	/* Handle the nop case quietly. */
+	if (new_size == old_size)
+		return ifp->if_broot;
+
+	if (new_size > old_size) {
+		unsigned int	old_numrecs;
+
+		/*
+		 * If there wasn't any memory allocated before, just
+		 * allocate it now and get out.
+		 */
+		if (old_size == 0)
+			return xfs_broot_realloc(ifp, new_size);
+
+		/*
+		 * If there is already an existing if_broot, then we need
+		 * to realloc() it and shift the pointers to their new
+		 * location.  The records don't change location because
+		 * they are kept butted up against the btree block header.
+		 */
+		old_numrecs = xfs_bmbt_maxrecs(mp, old_size, false);
+		broot = xfs_broot_realloc(ifp, new_size);
+		ASSERT(xfs_bmap_bmdr_space(broot) <=
+			xfs_inode_fork_size(ip, whichfork));
+		xfs_bmbt_move_ptrs(mp, broot, old_size, new_size, old_numrecs);
+		return broot;
+	}
+
+	/*
+	 * We're reducing, but not totally eliminating, numrecs.  In this case,
+	 * we are shrinking the if_broot buffer, so it must already exist.
+	 */
+	ASSERT(ifp->if_broot != NULL && old_size > 0 && new_size > 0);
+
+	/*
+	 * Shrink the btree root by moving the bmbt pointers, since they are
+	 * not butted up against the btree block header, then reallocating
+	 * broot.
+	 */
+	xfs_bmbt_move_ptrs(mp, ifp->if_broot, old_size, new_size, new_numrecs);
+	broot = xfs_broot_realloc(ifp, new_size);
+	ASSERT(xfs_bmap_bmdr_space(broot) <=
+	       xfs_inode_fork_size(ip, whichfork));
+	return broot;
+}
+
+static struct xfs_btree_block *
+xfs_bmbt_broot_realloc(
+	struct xfs_btree_cur	*cur,
+	unsigned int		new_numrecs)
+{
+	return xfs_bmap_broot_realloc(cur->bc_ino.ip, cur->bc_ino.whichfork,
+			new_numrecs);
+}
+
 const struct xfs_btree_ops xfs_bmbt_ops = {
 	.name			= "bmap",
 	.type			= XFS_BTREE_TYPE_INODE,
@@ -537,12 +635,13 @@ const struct xfs_btree_ops xfs_bmbt_ops = {
 	.init_key_from_rec	= xfs_bmbt_init_key_from_rec,
 	.init_high_key_from_rec	= xfs_bmbt_init_high_key_from_rec,
 	.init_rec_from_cur	= xfs_bmbt_init_rec_from_cur,
-	.key_diff		= xfs_bmbt_key_diff,
-	.diff_two_keys		= xfs_bmbt_diff_two_keys,
+	.cmp_key_with_cur	= xfs_bmbt_cmp_key_with_cur,
+	.cmp_two_keys		= xfs_bmbt_cmp_two_keys,
 	.buf_ops		= &xfs_bmbt_buf_ops,
 	.keys_inorder		= xfs_bmbt_keys_inorder,
 	.recs_inorder		= xfs_bmbt_recs_inorder,
 	.keys_contiguous	= xfs_bmbt_keys_contiguous,
+	.broot_realloc		= xfs_bmbt_broot_realloc,
 };
 
 /*