[06/14] xfs: move the zero records logic into xfs_bmap_broot_space_calc

Commit Message

Darrick J. Wong Dec. 30, 2022, 10:17 p.m. UTC

From: Darrick J. Wong <[e-mail]>

The bmap btree cannot ever have zero records in an incore btree block.
If the number of records drops to zero, that means we're converting the
fork to extents format and are trying to remove the tree.  This logic
won't hold for the future realtime rmap btree, so move the logic into
the bmbt code.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 fs/xfs/libxfs/xfs_bmap_btree.h |    7 +++++++
 fs/xfs/libxfs/xfs_inode_fork.c |    6 ++----
 2 files changed, 9 insertions(+), 4 deletions(-)

Patch

diff --git a/fs/xfs/libxfs/xfs_bmap_btree.h b/fs/xfs/libxfs/xfs_bmap_btree.h
index 3fe9c4f7f1a0..5a3bae94debd 100644
--- a/fs/xfs/libxfs/xfs_bmap_btree.h
+++ b/fs/xfs/libxfs/xfs_bmap_btree.h
@@ -162,6 +162,13 @@  xfs_bmap_broot_space_calc(
 	struct xfs_mount	*mp,
 	unsigned int		nrecs)
 {
+	/*
+	 * If the bmbt root block is empty, we should be converting the fork
+	 * to extents format.  Hence, the size is zero.
+	 */
+	if (nrecs == 0)
+		return 0;
+
 	return xfs_bmbt_block_len(mp) + \
 	       (nrecs * (sizeof(struct xfs_bmbt_key) + sizeof(xfs_bmbt_ptr_t)));
 }
diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
index 16782d3630d2..1bd8c1f9ce37 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.c
+++ b/fs/xfs/libxfs/xfs_inode_fork.c
@@ -488,10 +488,8 @@  xfs_iroot_realloc(
 	cur_max = xfs_bmbt_maxrecs(mp, old_size, 0);
 	new_max = cur_max + rec_diff;
 	ASSERT(new_max >= 0);
-	if (new_max > 0)
-		new_size = xfs_bmap_broot_space_calc(mp, new_max);
-	else
-		new_size = 0;
+
+	new_size = xfs_bmap_broot_space_calc(mp, new_max);
 	if (new_size == 0) {
 		xfs_iroot_free(ip, whichfork);
 		return;