When an exceptional event triggers xfs_force_shutdown() tear down dax
mappings. Quoting Dave,
"The simple fact is that a /filesystem/ shutdown needs to do DAX
mapping invalidation regardless of whether the block device has
been unplugged or not. This is not a case of "this only happens
when we unplug the device", this is a user data protection
mechanism that we use to prevent corruption propagation once it
has been detected. A device unplug is just one type of
"corruption" that can occur."
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
fs/xfs/xfs_fsops.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index ee3aaa0a5317..0c6a52809dcc 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -828,6 +828,15 @@ xfs_do_force_shutdown(
if (xfs_log_force_umount(mp, logerror))
return;
+ /*
+ * If DAX is in use, we have to unmap all direct access virtual
+ * mappings to ensure nothing more gets written directly from
+ * userspace. This will force them to refault and that will
+ * result in them detecting the shutdown condition and hence
+ * will fail appropriately.
+ */
+ unmap_dax_inodes(mp->m_super);
+
if (flags & SHUTDOWN_CORRUPT_INCORE) {
xfs_alert_tag(mp, XFS_PTAG_SHUTDOWN_CORRUPT,
"Corruption of in-memory data detected. Shutting down filesystem");
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