ext4: get block from bh in ext4_free_blocks for fast commit replay

ext4_free_blocks will retrieve block from bh if block parameter is zero.
Retrieve block before ext4_free_blocks_simple to avoid potentially
passing wrong block to ext4_free_blocks_simple.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: stable@kernel.org
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20230603150327.3596033-9-shikemeng@huaweicloud.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/mballoc.c

@@ -6368,12 +6368,6 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
 
 	sbi = EXT4_SB(sb);
 
-	if (sbi->s_mount_state & EXT4_FC_REPLAY) {
-		ext4_free_blocks_simple(inode, block, count);
-		return;
-	}
-
-	might_sleep();
 	if (bh) {
 		if (block)
 			BUG_ON(block != bh->b_blocknr);
@@ -6381,6 +6375,13 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
 			block = bh->b_blocknr;
 	}
 
+	if (sbi->s_mount_state & EXT4_FC_REPLAY) {
+		ext4_free_blocks_simple(inode, block, count);
+		return;
+	}
+
+	might_sleep();
+
 	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
 	    !ext4_inode_block_valid(inode, block, count)) {
 		ext4_error(sb, "Freeing blocks not in datazone - "