Re: [PATCH 1/5] xfs_repair: refuse to run if we don't recognize version or feature flags

[Eric Sandeen <sandeen@sandeen.net>]

On 5/26/15 5:51 PM, Darrick J. Wong wrote:
> Apparently xfs_repair running on a v5 filesystem doesn't check the
> compat, rocompat, or incompat feature flags for bits that it doesn't
> know about, which means that old xfs_repairs can wreak havoc.  So,
> strengthen the checks to prevent repair from "repairing" anything it
> doesn't understand.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  repair/versions.c |    7 +++++++
>  1 file changed, 7 insertions(+)
> 
> 
> diff --git a/repair/versions.c b/repair/versions.c
> index c1dff72..e60574d 100644
> --- a/repair/versions.c
> +++ b/repair/versions.c
> @@ -141,6 +141,13 @@ parse_sb_version(xfs_sb_t *sb)
>  		}
>  	}
>  
> +	/* Look for V5 feature flags we don't know about */
> +	if (XFS_SB_VERSION_NUM(sb) >= XFS_SB_VERSION_5 &&
> +	    (xfs_sb_has_ro_compat_feature(sb, XFS_SB_FEAT_RO_COMPAT_UNKNOWN) ||
> +	     xfs_sb_has_incompat_feature(sb, XFS_SB_FEAT_INCOMPAT_UNKNOWN) ||
> +	     xfs_sb_has_compat_feature(sb, XFS_SB_FEAT_COMPAT_UNKNOWN)))
> +		issue_warning = 1;
> +

should this go after the xfs_sb_good_version() check?

Seems like it's more of a fine-grained check on features for a given super
version, and should come after that check.

i.e. if for some reason XFS_SB_VERSION_NUM == 6, the root problem isn't
the feature set, it's the superblock version number.

And; would it be worth printing out what the features are?  I guess we have
no good existing mechanism for that, and could really only print hex values...
still, might be useful for bug reports...

-Eric


>  	if (issue_warning)  {
>  		do_warn(
>  _("This filesystem uses feature(s) not yet supported in this release.\n"
> 
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