[PATCH 11/16] xfs: add xfs_dir2_block_overhead helper

[Christoph Hellwig <hch@lst.de>]

Add a common helper for the calculation of the overhead when converting
a shortform to block format directory.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/libxfs/xfs_dir2_block.c |  4 ++--
 fs/xfs/libxfs/xfs_dir2_priv.h  | 12 ++++++++++++
 fs/xfs/libxfs/xfs_dir2_sf.c    | 12 ++++--------
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_dir2_block.c b/fs/xfs/libxfs/xfs_dir2_block.c
index 378d3aefdd9ced..a19744cb43ca0c 100644
--- a/fs/xfs/libxfs/xfs_dir2_block.c
+++ b/fs/xfs/libxfs/xfs_dir2_block.c
@@ -1109,8 +1109,8 @@ xfs_dir2_sf_to_block(
 	/*
 	 * Compute size of block "tail" area.
 	 */
-	i = (uint)sizeof(*btp) +
-	    (sfp->count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t);
+	i = xfs_dir2_block_overhead(sfp->count);
+
 	/*
 	 * The whole thing is initialized to free by the init routine.
 	 * Say we're using the leaf and tail area.
diff --git a/fs/xfs/libxfs/xfs_dir2_priv.h b/fs/xfs/libxfs/xfs_dir2_priv.h
index 1e4401f9ec936e..bfbc73251f275a 100644
--- a/fs/xfs/libxfs/xfs_dir2_priv.h
+++ b/fs/xfs/libxfs/xfs_dir2_priv.h
@@ -205,4 +205,16 @@ xfs_dahash_t xfs_dir2_hashname(struct xfs_mount *mp,
 enum xfs_dacmp xfs_dir2_compname(struct xfs_da_args *args,
 		const unsigned char *name, int len);
 
+/*
+ * Overhead if we converted a shortform directory to block format.
+ *
+ * The extra two entries are because "." and ".." don't have real entries in
+ * the shortform format.
+ */
+static inline unsigned int xfs_dir2_block_overhead(unsigned int count)
+{
+	return (count + 2) * sizeof(struct xfs_dir2_leaf_entry) +
+		sizeof(struct xfs_dir2_block_tail);
+}
+
 #endif /* __XFS_DIR2_PRIV_H__ */
diff --git a/fs/xfs/libxfs/xfs_dir2_sf.c b/fs/xfs/libxfs/xfs_dir2_sf.c
index 21e04594606b89..1e1dcdf83b8f95 100644
--- a/fs/xfs/libxfs/xfs_dir2_sf.c
+++ b/fs/xfs/libxfs/xfs_dir2_sf.c
@@ -629,9 +629,7 @@ xfs_dir2_sf_addname_pick(
 	 * Calculate data bytes used excluding the new entry, if this
 	 * was a data block (block form directory).
 	 */
-	used = offset +
-	       (sfp->count + 3) * (uint)sizeof(xfs_dir2_leaf_entry_t) +
-	       (uint)sizeof(xfs_dir2_block_tail_t);
+	used = offset + xfs_dir2_block_overhead(sfp->count + 1);
 	/*
 	 * If it won't fit in a block form then we can't insert it,
 	 * we'll go back, convert to block, then try the insert and convert
@@ -691,9 +689,7 @@ xfs_dir2_sf_check(
 	}
 	ASSERT(i8count == sfp->i8count);
 	ASSERT((char *)sfep - (char *)sfp == dp->i_disk_size);
-	ASSERT(offset +
-	       (sfp->count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t) +
-	       (uint)sizeof(xfs_dir2_block_tail_t) <= args->geo->blksize);
+	ASSERT(offset + xfs_dir2_block_overhead(sfp->count));
 }
 #endif	/* DEBUG */
 
@@ -782,8 +778,8 @@ xfs_dir2_sf_verify(
 		return __this_address;
 
 	/* Make sure this whole thing ought to be in local format. */
-	if (offset + (sfp->count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t) +
-	    (uint)sizeof(xfs_dir2_block_tail_t) > mp->m_dir_geo->blksize)
+	if (offset + xfs_dir2_block_overhead(sfp->count) >
+	    mp->m_dir_geo->blksize)
 		return __this_address;
 
 	return NULL;
-- 
2.39.2