[PATCH RFC 10/17] ext4: use fast incremental CRC update in ext4_free_inode()

[Baokun Li <libaokun@linux.alibaba.com>]

Replace ext4_inode_bitmap_csum_set() with the newly added
ext4_inode_bitmap_csum_set_fast() in ext4_free_inode() for incremental
inode bitmap checksum update.

This is safe because:
 - At inode free time, the inode bitmap checksum has already been
   initialized, so the old checksum is always valid.
 - The bitmap buffer modification and checksum update are protected
   by the same group lock, ensuring the old checksum is consistent
   with the bitmap content before the bit flip.

Signed-off-by: Baokun Li <libaokun@linux.alibaba.com>
---
 fs/ext4/ialloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 3fd8f0099852..55eb69fbb4c9 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -327,7 +327,7 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
 		if (percpu_counter_initialized(&sbi->s_dirs_counter))
 			percpu_counter_dec(&sbi->s_dirs_counter);
 	}
-	ext4_inode_bitmap_csum_set(sb, gdp, bitmap_bh);
+	ext4_inode_bitmap_csum_set_fast(sb, gdp, bit);
 	ext4_group_desc_csum_set(sb, block_group, gdp);
 	ext4_unlock_group(sb, block_group);
 
-- 
2.43.7