On Sat, Mar 12, 2022 at 11:44:49PM -0500, Theodore Ts'o wrote:
From: Josh Triplett josh@joshtriplett.org
commit b1489186cc8391e0c1e342f9fbc3eedf6b944c61 upstream.
The in-kernel ext4 resize code doesn't support filesystem with the sparse_super2 feature. It fails with errors like this and doesn't finish the resize:
EXT4-fs (loop0): resizing filesystem from 16640 to 7864320 blocks EXT4-fs warning (device loop0): verify_reserved_gdb:760: reserved GDT 2 missing grp 1 (32770) EXT4-fs warning (device loop0): ext4_resize_fs:2111: error (-22) occurred during file system resize EXT4-fs (loop0): resized filesystem to 2097152
To reproduce: 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
The userspace resize2fs tool has a check for this case: it checks if the filesystem has sparse_super2 set and if the kernel provides /sys/fs/ext4/features/sparse_super2. However, the former check requires manually reading and parsing the filesystem superblock.
Detect this case in ext4_resize_begin and error out early with a clear error message.
Signed-off-by: Josh Triplett josh@joshtriplett.org Link: https://lore.kernel.org/r/74b8ae78405270211943cd7393e65586c5faeed1.162309325... Signed-off-by: Theodore Ts'o tytso@mit.edu
fs/ext4/resize.c | 5 +++++ 1 file changed, 5 insertions(+)
Now queued up, thanks.
greg k-h