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

Darrick J. Wong
2017-10-26T05:49:39Z

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>
---
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;