Re: [PATCH 1/3] xfs: move kernel-specific superblock validation out of libxfs

[Brian Foster <bfoster@redhat.com>]

On Sun, Dec 06, 2020 at 03:09:26PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> A couple of the superblock validation checks apply only to the kernel,
> so move them to xfs_fc_fill_super before we add the needsrepair "feature",
> which will prevent the kernel (but not xfsprogs) from mounting the
> filesystem.  This also reduces the diff between kernel and userspace
> libxfs.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/libxfs/xfs_sb.c |   27 ---------------------------
>  fs/xfs/xfs_super.c     |   32 ++++++++++++++++++++++++++++++++
>  2 files changed, 32 insertions(+), 27 deletions(-)
> 
> 
> diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
> index 5aeafa59ed27..05359690aaed 100644
> --- a/fs/xfs/libxfs/xfs_sb.c
> +++ b/fs/xfs/libxfs/xfs_sb.c
> @@ -382,17 +382,6 @@ xfs_validate_sb_common(
>  		return -EFSCORRUPTED;
>  	}
>  
> -	/*
> -	 * Until this is fixed only page-sized or smaller data blocks work.
> -	 */
> -	if (unlikely(sbp->sb_blocksize > PAGE_SIZE)) {
> -		xfs_warn(mp,
> -		"File system with blocksize %d bytes. "
> -		"Only pagesize (%ld) or less will currently work.",
> -				sbp->sb_blocksize, PAGE_SIZE);
> -		return -ENOSYS;
> -	}
> -
>  	/*
>  	 * Currently only very few inode sizes are supported.
>  	 */
> @@ -408,22 +397,6 @@ xfs_validate_sb_common(
>  		return -ENOSYS;
>  	}
>  
> -	if (xfs_sb_validate_fsb_count(sbp, sbp->sb_dblocks) ||
> -	    xfs_sb_validate_fsb_count(sbp, sbp->sb_rblocks)) {
> -		xfs_warn(mp,
> -		"file system too large to be mounted on this system.");
> -		return -EFBIG;
> -	}
> -
> -	/*
> -	 * Don't touch the filesystem if a user tool thinks it owns the primary
> -	 * superblock.  mkfs doesn't clear the flag from secondary supers, so
> -	 * we don't check them at all.
> -	 */
> -	if (XFS_BUF_ADDR(bp) == XFS_SB_DADDR && sbp->sb_inprogress) {
> -		xfs_warn(mp, "Offline file system operation in progress!");
> -		return -EFSCORRUPTED;
> -	}
>  	return 0;
>  }
>  
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index e3e229e52512..599566c1a3b4 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1467,6 +1467,38 @@ xfs_fc_fill_super(
>  #endif
>  	}
>  
> +	/*
> +	 * Don't touch the filesystem if a user tool thinks it owns the primary
> +	 * superblock.  mkfs doesn't clear the flag from secondary supers, so
> +	 * we don't check them at all.
> +	 */
> +	if (mp->m_sb.sb_inprogress) {
> +		xfs_warn(mp, "Offline file system operation in progress!");
> +		error = -EFSCORRUPTED;
> +		goto out_free_sb;
> +	}
> +
> +	/*
> +	 * Until this is fixed only page-sized or smaller data blocks work.
> +	 */
> +	if (mp->m_sb.sb_blocksize > PAGE_SIZE) {
> +		xfs_warn(mp,
> +		"File system with blocksize %d bytes. "
> +		"Only pagesize (%ld) or less will currently work.",
> +				mp->m_sb.sb_blocksize, PAGE_SIZE);
> +		error = -ENOSYS;
> +		goto out_free_sb;
> +	}
> +
> +	/* Ensure this filesystem fits in the page cache limits */
> +	if (xfs_sb_validate_fsb_count(&mp->m_sb, mp->m_sb.sb_dblocks) ||
> +	    xfs_sb_validate_fsb_count(&mp->m_sb, mp->m_sb.sb_rblocks)) {
> +		xfs_warn(mp,
> +		"file system too large to be mounted on this system.");
> +		error = -EFBIG;
> +		goto out_free_sb;
> +	}
> +
>  	/*
>  	 * XFS block mappings use 54 bits to store the logical block offset.
>  	 * This should suffice to handle the maximum file size that the VFS
>