Re: [PATCH 3/4] xfs: validate sb_logsunit is a multiple of the fs blocksize

Brian Foster
2017-10-26T13:16:50Z

On Wed, Oct 25, 2017 at 10:49:36PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
>
> Make sure the log stripe unit is sane before proceeding with mounting.
> AFAICT this means that logsunit has to be 0, 1, or a multiple of the fs
> block size. Found this by setting the LSB of logsunit in xfs/350 and
> watching the system crash as soon as we try to write to the log.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---

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

> fs/xfs/xfs_log.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
>
> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
> index dc95a49..4edb36f 100644
> --- a/fs/xfs/xfs_log.c
> +++ b/fs/xfs/xfs_log.c
> @@ -608,6 +608,7 @@ xfs_log_mount(
> xfs_daddr_t blk_offset,
> int num_bblks)
> {
> + bool fatal = xfs_sb_version_hascrc(&mp->m_sb);
> int error = 0;
> int min_logfsbs;
>
> @@ -659,9 +660,20 @@ xfs_log_mount(
> XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks),
> XFS_MAX_LOG_BYTES);
> error = -EINVAL;
> + } else if (mp->m_sb.sb_logsunit > 1 &&
> + mp->m_sb.sb_logsunit % mp->m_sb.sb_blocksize) {
> + xfs_warn(mp,
> + "log stripe unit %u bytes must be a multiple of block size",
> + mp->m_sb.sb_logsunit);
> + error = -EINVAL;
> + fatal = true;
> }
> if (error) {
> - if (xfs_sb_version_hascrc(&mp->m_sb)) {
> + /*
> + * Log check errors are always fatal on v5; or whenever bad
> + * metadata leads to a crash.
> + */
> + if (fatal) {
> xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
> ASSERT(0);
> goto out_free_log;