Re: [PATCH] ext4: Fix maximum orphan file size check

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

On 2026/10/2 19:50, Jan Kara wrote:
> Mikulas reported that e2fsprogs 1.47.4 with 1k fs blocksize by default
> creates orphan file of the size the kernel rejects. This is because that
> version of e2fsprogs creates 2MB file by default regardless of the block
> size and with 1k blocks that's more than the limit of 512 fs blocks.
> Fix the check to make kernel accept any file upto those 2MB regardless
> of the number of blocks.
>
> Fixes: 7c11c56eb32e ("ext4: align max orphan file size with e2fsprogs limit")
> CC: stable@vger.kernel.org
> Reported-by: Mikulas Patocka <mpatocka@redhat.com>
> Link: https://lore.kernel.org/all/e65cdbfe-3ff9-4638-fbd3-4d8f8880966f@redhat.com
> Signed-off-by: Jan Kara <jack@suse.cz>

Thanks for fixing this.

The problem is only triggered by images created with the problematic
e2fsprogs: 1k-block filesystems between 512MiB and 2GiB, and 2k-block
filesystems between 2GiB and 4GiB.

A more thorough fix would be to rebuild the orphan file with tune2fs.
However, some instances may not get the chance to do that. So I think
it's good to keep the kernel compatible with both versions of
e2fsprogs. Feel free to add:

Reviewed-by: Baokun Li <libaokun@linux.alibaba.com>

> ---
>  fs/ext4/orphan.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/orphan.c b/fs/ext4/orphan.c
> index b4675aa7ea96..7394d04e0fd9 100644
> --- a/fs/ext4/orphan.c
> +++ b/fs/ext4/orphan.c
> @@ -576,6 +576,7 @@ int ext4_init_orphan_info(struct super_block *sb)
>  	int inodes_per_ob = ext4_inodes_per_orphan_block(sb);
>  	struct ext4_orphan_block_tail *ot;
>  	ino_t orphan_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_orphan_file_inum);
> +	loff_t max_size;
>  
>  	if (!ext4_has_feature_orphan_file(sb))
>  		return 0;
> @@ -589,8 +590,13 @@ int ext4_init_orphan_info(struct super_block *sb)
>  	 * This is just an artificial limit to prevent corrupted fs from
>  	 * consuming absurd amounts of memory when pinning blocks of orphan
>  	 * file in memory.
> +	 *
> +	 * e2fsprogs 1.47.4 produces 2MB orphan files by default regardless
> +	 * of the number of blocks so that's where the second limit comes from.
>  	 */
> -	if (inode->i_size > (EXT4_MAX_ORPHAN_FILE_BLOCKS << inode->i_blkbits)) {
> +	max_size = max(EXT4_MAX_ORPHAN_FILE_BLOCKS << inode->i_blkbits,
> +		       2 << 20);
> +	if (inode->i_size > max_size) {
>  		ext4_msg(sb, KERN_ERR, "orphan file too big: %llu",
>  			 (unsigned long long)inode->i_size);
>  		ret = -EFSCORRUPTED;