[PATCH RFC 3/9] ext4: add ext4_inode_loc_block() helper

[Christian Brauner <brauner@kernel.org>]

Move the lookup of the inode table block out of
ext4_get_inode_loc_noio() into a helper. ext4_sync_inode_metadata() is
going to use it to find the block without reading it from disk.

No functional changes.

Cc: stable@vger.kernel.org # v7.3
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 fs/ext4/inode.c | 38 +++++++++++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index b4d581aa5ee1..b34b99d15db6 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5874,16 +5874,14 @@ int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
 }
 
 /*
- * ext4_get_inode_loc_noio() is a best-effort variant of ext4_get_inode_loc().
- * It looks up the inode table block in the buffer cache and returns -EAGAIN if
- * the block is not present or not uptodate, without starting any I/O.
+ * Find the inode table block that holds @inode without looking at the block
+ * itself. Fills in iloc->block_group and iloc->offset.
  */
-int ext4_get_inode_loc_noio(struct inode *inode, struct ext4_iloc *iloc)
+static int ext4_inode_loc_block(struct inode *inode, struct ext4_iloc *iloc,
+				ext4_fsblk_t *block)
 {
 	struct super_block *sb = inode->i_sb;
 	struct ext4_group_desc *gdp;
-	struct buffer_head *bh;
-	ext4_fsblk_t block;
 	int inodes_per_block, inode_offset;
 	unsigned long ino = inode->i_ino;
 
@@ -5902,15 +5900,33 @@ int ext4_get_inode_loc_noio(struct inode *inode, struct ext4_iloc *iloc)
 	inode_offset = ((ino - 1) % EXT4_INODES_PER_GROUP(sb));
 	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
 
-	block = ext4_inode_table(sb, gdp);
-	if (block <= le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) ||
-	    block >= ext4_blocks_count(EXT4_SB(sb)->s_es)) {
+	*block = ext4_inode_table(sb, gdp);
+	if (*block <= le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) ||
+	    *block >= ext4_blocks_count(EXT4_SB(sb)->s_es)) {
 		ext4_error(sb,
 			   "Invalid inode table block %llu in block_group %u",
-			   block, iloc->block_group);
+			   *block, iloc->block_group);
 		return -EFSCORRUPTED;
 	}
-	block += inode_offset / inodes_per_block;
+	*block += inode_offset / inodes_per_block;
+	return 0;
+}
+
+/*
+ * ext4_get_inode_loc_noio() is a best-effort variant of ext4_get_inode_loc().
+ * It looks up the inode table block in the buffer cache and returns -EAGAIN if
+ * the block is not present or not uptodate, without starting any I/O.
+ */
+int ext4_get_inode_loc_noio(struct inode *inode, struct ext4_iloc *iloc)
+{
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *bh;
+	ext4_fsblk_t block;
+	int err;
+
+	err = ext4_inode_loc_block(inode, iloc, &block);
+	if (err)
+		return err;
 
 	bh = sb_find_get_block(sb, block);
 	if (!bh)

-- 
2.53.0