FAILED: patch "[PATCH] ext4: fix dir corruption when ext4_dx_add_entry() fails" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Possible dependencies:

7177dd009c7c ("ext4: fix dir corruption when ext4_dx_add_entry() fails") 188c299e2a26 ("ext4: Support for checksumming from journal triggers") c915fb80eaa6 ("ext4: fix bh ref count on error paths") a3f5cf14ff91 ("ext4: drop ext4_handle_dirty_super()") 05c2c00f3769 ("ext4: protect superblock modifications with a buffer lock") 4392fbc4bab5 ("ext4: drop sync argument of ext4_commit_super()") c92dc856848f ("ext4: defer saving error info from atomic context") 02a7780e4d2f ("ext4: simplify ext4 error translation") 4067662388f9 ("ext4: move functions in super.c")
014c9caa29d3 ("ext4: make ext4_abort() use __ext4_error()") b08070eca9e2 ("ext4: don't remount read-only with errors=continue on reboot") ca9b404ff137 ("ext4: print quota journalling mode on (re-)mount")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7177dd009c7c04290891e9a534cd47d1b620bd04 Mon Sep 17 00:00:00 2001
From: Zhihao Cheng <[email protected]>
Date: Sun, 11 Sep 2022 12:52:04 +0800
Subject: [PATCH] ext4: fix dir corruption when ext4_dx_add_entry() fails

Following process may lead to fs corruption:
1. ext4_create(dir/foo)
ext4_add_nondir
ext4_add_entry
ext4_dx_add_entry

     a. add_dirent_to_buf
      ext4_mark_inode_dirty
      ext4_handle_dirty_metadata   // dir inode bh is recorded into journal
     b. ext4_append    // dx_get_count(entries) == dx_get_limit(entries)
       ext4_bread(EXT4_GET_BLOCKS_CREATE)
        ext4_getblk
         ext4_map_blocks
          ext4_ext_map_blocks
            ext4_mb_new_blocks
             dquot_alloc_block
              dquot_alloc_space_nodirty
               inode_add_bytes    // update dir's i_blocks
            ext4_ext_insert_extent
	     ext4_ext_dirty  // record extent bh into journal
              ext4_handle_dirty_metadata(bh)
	      // record new block into journal
       inode->i_size += inode->i_sb->s_blocksize   // new size(in mem)
     c. ext4_handle_dirty_dx_node(bh2)
	// record dir's new block(dx_node) into journal
     d. ext4_handle_dirty_dx_node((frame - 1)->bh)
     e. ext4_handle_dirty_dx_node(frame->bh)
     f. do_split    // ret err!
     g. add_dirent_to_buf
	 ext4_mark_inode_dirty(dir)  // update raw_inode on disk(skipped)

2. fsck -a /dev/sdb
drop last block(dx_node) which beyonds dir's i_size.
/dev/sdb: recovering journal
/dev/sdb contains a file system with errors, check forced. /dev/sdb: Inode 12, end of extent exceeds allowed value

	(logical block 128, physical block 3938, len 1)

3. fsck -fn /dev/sdb
dx_node->entry[i].blk > dir->i_size
Pass 2: Checking directory structure
Problem in HTREE directory inode 12 (/dir): bad block number 128. Clear HTree index? no
Problem in HTREE directory inode 12: block #3 has invalid depth (2) Problem in HTREE directory inode 12: block #3 has bad max hash Problem in HTREE directory inode 12: block #3 not referenced

Fix it by marking inode dirty directly inside ext4_append(). Fetch a reproducer in [Link].

index bc2e0612ec32..4183a4cb4a21 100644
@@ -85,15 +85,20 @@ static struct buffer_head *ext4_append(handle_t *handle,
 		return bh;
 	inode->i_size += inode->i_sb->s_blocksize;
 	EXT4_I(inode)->i_disksize = inode->i_size;
+	err = ext4_mark_inode_dirty(handle, inode);
+	if (err)
+		goto out;
 	BUFFER_TRACE(bh, "get_write_access");
 	err = ext4_journal_get_write_access(handle, inode->i_sb, bh,
 					    EXT4_JTR_NONE);
-	if (err) {
-		brelse(bh);
-		ext4_std_error(inode->i_sb, err);
-		return ERR_PTR(err);
-	}
+	if (err)
+		goto out;
 	return bh;
+
+out:
+	brelse(bh);
+	ext4_std_error(inode->i_sb, err);
+	return ERR_PTR(err);
 }
 
 static int ext4_dx_csum_verify(struct inode *inode,