Re: [PATCH v2] Btrfs: Remove the check for old-style mkfs

[Omar Sandoval <osandov@osandov.com>]

On Tue, Mar 17, 2015 at 02:34:16PM +0800, Liu Bo wrote:
> This was used to make sure that a fresh btrfs from an older mkfs.btrfs,
> but it also allows us to mount a buggy btrfs if this btrfs has the right
> superblock head part but has something wrong with chunk tree part[1], and
> after that we can hit BUG_ON()s set in the code to prevent something
> impossible.
> 
> Since David has released "Btrfs progs v3.19-rc2", just remove the check,
> if anyone who wants to make a fresh btrfs, please use the latest one.
> 
> [1]: http://www.spinics.net/lists/linux-btrfs/msg42358.html
> 
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>

# mount -o loop btrfs.img /mnt/test
# dmesg | tail
[   28.582698] BTRFS: device fsid 1c0ed5d6-550d-4010-b1b4-ce1828270713 devid 1 transid 4 /dev/loop0
[   28.598365] BTRFS: superblock checksum mismatch
[   28.617205] BTRFS: open_ctree failed

Looks good to me.

Reviewed-by: Omar Sandoval <osandov@osandov.com>

> ---
> v2: Refine the patch subject.
> 
>  fs/btrfs/disk-io.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 41b320e..f63aacf 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -418,12 +418,6 @@ static int btrfs_check_super_csum(char *raw_disk_sb)
>  
>  		if (memcmp(raw_disk_sb, result, csum_size))
>  			ret = 1;
> -
> -		if (ret && btrfs_super_generation(disk_sb) < 10) {
> -			printk(KERN_WARNING
> -				"BTRFS: super block crcs don't match, older mkfs detected\n");
> -			ret = 0;
> -		}
>  	}
>  
>  	if (csum_type >= ARRAY_SIZE(btrfs_csum_sizes)) {
> -- 
> 1.8.1.4
> 
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-- 
Omar