xfs: quiet notify_failure EOPNOTSUPP cases

Patch series "mm, xfs, dax: Fixes for memory_failure() handling".

I failed to run the memory error injection section of the ndctl test suite
on linux-next prior to the merge window and as a result some bugs were
missed.  While the new enabling targeted reflink enabled XFS filesystems
the bugs cropped up in the surrounding cases of DAX error injection on
ext4-fsdax and device-dax.

One new assumption / clarification in this set is the notion that if a
filesystem's ->notify_failure() handler returns -EOPNOTSUPP, then it must
be the case that the fsdax usage of page->index and page->mapping are
valid.  I am fairly certain this is true for xfs_dax_notify_failure(), but
would appreciate another set of eyes.


This patch (of 4):

XFS always registers dax_holder_operations regardless of whether the
filesystem is capable of handling the notifications.  The expectation is
that if the notify_failure handler cannot run then there are no scenarios
where it needs to run.  In other words the expected semantic is that
page->index and page->mapping are valid for memory_failure() when the
conditions that cause -EOPNOTSUPP in xfs_dax_notify_failure() are present.

A fallback to the generic memory_failure() path is expected so do not warn
when that happens.

Link: https://lkml.kernel.org/r/166153426798.2758201.15108211981034512993.stgit@dwillia2-xfh.jf.intel.com
Link: https://lkml.kernel.org/r/166153427440.2758201.6709480562966161512.stgit@dwillia2-xfh.jf.intel.com
Fixes: 6f643c57d57c ("xfs: implement ->notify_failure() for XFS")
Signed-off-by: Dan Williams <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Shiyang Ruan <[email protected]>
Cc: Darrick J. Wong <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Goldwyn Rodrigues <[email protected]>
Cc: Jane Chu <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Ritesh Harjani <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/xfs/xfs_notify_failure.c b/fs/xfs/xfs_notify_failure.c
index 69d9c83ea4b2..01e2721589c4 100644
--- a/fs/xfs/xfs_notify_failure.c
+++ b/fs/xfs/xfs_notify_failure.c
@@ -181,7 +181,7 @@ xfs_dax_notify_failure(
 	}
 
 	if (mp->m_rtdev_targp && mp->m_rtdev_targp->bt_daxdev == dax_dev) {
-		xfs_warn(mp,
+		xfs_debug(mp,
 			 "notify_failure() not supported on realtime device!");
 		return -EOPNOTSUPP;
 	}
@@ -194,7 +194,7 @@ xfs_dax_notify_failure(
 	}
 
 	if (!xfs_has_rmapbt(mp)) {
-		xfs_warn(mp, "notify_failure() needs rmapbt enabled!");
+		xfs_debug(mp, "notify_failure() needs rmapbt enabled!");
 		return -EOPNOTSUPP;
 	}