ACK: [Patch 0/2] [F/I linux-azure] Xfstest failure with sparse_super2 mount option

[Philip Cox]

Acked-By Philip Cox <philip.cox at canonical.com>

On 2022-04-25 10:12 a.m., Tim Gardner wrote:
> BugLink: https://bugs.launchpad.net/bugs/1970223
>
> SRU Justification
>
> [Impact]
>
> Microsoft has detected an Xfstest failure scenario. There might be fs corruption
> when resizing ext4 filesystems mounted with sparse_super2 option enabled.
>
> Fix: commit b1489186cc8391e0c1e342f9fbc3eedf6b944c61 ("ext4: add check to
> prevent attempting to resize an fs with sparse_super2")
>
> [Test Case]
> mkfs.ext4 -b 4096 -I 256 -J size=32 -E resize=$((256*1024*1024)) -O sparse_super2 ext4.img 65M truncate -s 30G ext4.img
> mount ext4.img /mnt
> python3 -c 'import fcntl, os, struct ; fd = os.open("/mnt", os.O_RDONLY | os.O_DIRECTORY) ; fcntl.ioctl(fd, 0x40086610, struct.pack("Q", 30 * 1024 * 1024 * 1024 // 4096), False) ; os.close(fd)'
> dmesg | tail
> e2fsck ext4.img
>
> [Where things could go wrong]
>
> The file system may erroneously not mount.
>
> [Other Info]
>
> SF: #00334996
>
>