Commit 8ef9313cf2 ("btrfs-progs: zoned: implement log-structured
superblock") changed to write BTRFS_SUPER_INFO_SIZE bytes to device.
The before num of bytes to be written is sectorsize.
It causes mkfs.btrfs failed on my 16k pagesize kvm:
$ /usr/bin/mkfs.btrfs -s 16k -f -mraid0 /dev/vdb2 /dev/vdb3
btrfs-progs v5.12
See http://btrfs.wiki.kernel.org for more information.
ERROR: superblock magic doesn't match
ERROR: superblock magic doesn't match
common/device-scan.c:195: btrfs_add_to_fsid: BUG_ON `ret != sectorsize`
triggered, value 1
/usr/bin/mkfs.btrfs(btrfs_add_to_fsid+0x274)[0xaaab4fe8a5fc]
/usr/bin/mkfs.btrfs(main+0x1188)[0xaaab4fe4dc8c]
/usr/lib/libc.so.6(__libc_start_main+0xe8)[0xffff7223c538]
/usr/bin/mkfs.btrfs(+0xc558)[0xaaab4fe4c558]
[1] 225842 abort (core dumped) /usr/bin/mkfs.btrfs -s 16k -f -mraid0
/dev/vdb2 /dev/vdb3
btrfs_add_to_fsid() now always calls sbwrite() to write
BTRFS_SUPER_INFO_SIZE bytes to device, so change condition of
the BUG_ON().
Also add comments for sbread() and sbwrite().
Signed-off-by: Su Yue <l@damenly.su>
Signed-off-by: David Sterba <dsterba@suse.com>