--- /dev/null
+From f99a8e4373eeacb279bc9696937a55adbff7a28a Mon Sep 17 00:00:00 2001
+From: Heinz Mauelshagen <heinzm@redhat.com>
+Date: Wed, 21 Apr 2021 23:32:36 +0200
+Subject: dm raid: fix inconclusive reshape layout on fast raid4/5/6 table reload sequences
+
+From: Heinz Mauelshagen <heinzm@redhat.com>
+
+commit f99a8e4373eeacb279bc9696937a55adbff7a28a upstream.
+
+If fast table reloads occur during an ongoing reshape of raid4/5/6
+devices the target may race reading a superblock vs the the MD resync
+thread; causing an inconclusive reshape state to be read in its
+constructor.
+
+lvm2 test lvconvert-raid-reshape-stripes-load-reload.sh can cause
+BUG_ON() to trigger in md_run(), e.g.:
+"kernel BUG at drivers/md/raid5.c:7567!".
+
+Scenario triggering the bug:
+
+1. the MD sync thread calls end_reshape() from raid5_sync_request()
+ when done reshaping. However end_reshape() _only_ updates the
+ reshape position to MaxSector keeping the changed layout
+ configuration though (i.e. any delta disks, chunk sector or RAID
+ algorithm changes). That inconclusive configuration is stored in
+ the superblock.
+
+2. dm-raid constructs a mapping, loading named inconsistent superblock
+ as of step 1 before step 3 is able to finish resetting the reshape
+ state completely, and calls md_run() which leads to mentioned bug
+ in raid5.c.
+
+3. the MD RAID personality's finish_reshape() is called; which resets
+ the reshape information on chunk sectors, delta disks, etc. This
+ explains why the bug is rarely seen on multi-core machines, as MD's
+ finish_reshape() superblock update races with the dm-raid
+ constructor's superblock load in step 2.
+
+Fix identifies inconclusive superblock content in the dm-raid
+constructor and resets it before calling md_run(), factoring out
+identifying checks into rs_is_layout_change() to share in existing
+rs_reshape_requested() and new rs_reset_inclonclusive_reshape(). Also
+enhance a comment and remove an empty line.
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
+Signed-off-by: Mike Snitzer <snitzer@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/md/dm-raid.c | 34 ++++++++++++++++++++++++++++------
+ 1 file changed, 28 insertions(+), 6 deletions(-)
+
+--- a/drivers/md/dm-raid.c
++++ b/drivers/md/dm-raid.c
+@@ -1892,6 +1892,14 @@ static bool rs_takeover_requested(struct
+ return rs->md.new_level != rs->md.level;
+ }
+
++/* True if layout is set to reshape. */
++static bool rs_is_layout_change(struct raid_set *rs, bool use_mddev)
++{
++ return (use_mddev ? rs->md.delta_disks : rs->delta_disks) ||
++ rs->md.new_layout != rs->md.layout ||
++ rs->md.new_chunk_sectors != rs->md.chunk_sectors;
++}
++
+ /* True if @rs is requested to reshape by ctr */
+ static bool rs_reshape_requested(struct raid_set *rs)
+ {
+@@ -1904,9 +1912,7 @@ static bool rs_reshape_requested(struct
+ if (rs_is_raid0(rs))
+ return false;
+
+- change = mddev->new_layout != mddev->layout ||
+- mddev->new_chunk_sectors != mddev->chunk_sectors ||
+- rs->delta_disks;
++ change = rs_is_layout_change(rs, false);
+
+ /* Historical case to support raid1 reshape without delta disks */
+ if (rs_is_raid1(rs)) {
+@@ -2843,7 +2849,7 @@ static sector_t _get_reshape_sectors(str
+ }
+
+ /*
+- *
++ * Reshape:
+ * - change raid layout
+ * - change chunk size
+ * - add disks
+@@ -2953,6 +2959,20 @@ static int rs_setup_reshape(struct raid_
+ }
+
+ /*
++ * If the md resync thread has updated superblock with max reshape position
++ * at the end of a reshape but not (yet) reset the layout configuration
++ * changes -> reset the latter.
++ */
++static void rs_reset_inconclusive_reshape(struct raid_set *rs)
++{
++ if (!rs_is_reshaping(rs) && rs_is_layout_change(rs, true)) {
++ rs_set_cur(rs);
++ rs->md.delta_disks = 0;
++ rs->md.reshape_backwards = 0;
++ }
++}
++
++/*
+ * Enable/disable discard support on RAID set depending on
+ * RAID level and discard properties of underlying RAID members.
+ */
+@@ -3221,11 +3241,14 @@ static int raid_ctr(struct dm_target *ti
+ if (r)
+ goto bad;
+
++ /* Catch any inconclusive reshape superblock content. */
++ rs_reset_inconclusive_reshape(rs);
++
+ /* Start raid set read-only and assumed clean to change in raid_resume() */
+ rs->md.ro = 1;
+ rs->md.in_sync = 1;
+
+- /* Keep array frozen */
++ /* Keep array frozen until resume. */
+ set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
+
+ /* Has to be held on running the array */
+@@ -3239,7 +3262,6 @@ static int raid_ctr(struct dm_target *ti
+ }
+
+ r = md_start(&rs->md);
+-
+ if (r) {
+ ti->error = "Failed to start raid array";
+ mddev_unlock(&rs->md);
--- /dev/null
+From 2417b9869b81882ab90fd5ed1081a1cb2d4db1dd Mon Sep 17 00:00:00 2001
+From: Paul Clements <paul.clements@us.sios.com>
+Date: Thu, 15 Apr 2021 17:17:57 -0400
+Subject: md/raid1: properly indicate failure when ending a failed write request
+
+From: Paul Clements <paul.clements@us.sios.com>
+
+commit 2417b9869b81882ab90fd5ed1081a1cb2d4db1dd upstream.
+
+This patch addresses a data corruption bug in raid1 arrays using bitmaps.
+Without this fix, the bitmap bits for the failed I/O end up being cleared.
+
+Since we are in the failure leg of raid1_end_write_request, the request
+either needs to be retried (R1BIO_WriteError) or failed (R1BIO_Degraded).
+
+Fixes: eeba6809d8d5 ("md/raid1: end bio when the device faulty")
+Cc: stable@vger.kernel.org # v5.2+
+Signed-off-by: Paul Clements <paul.clements@us.sios.com>
+Signed-off-by: Song Liu <song@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/md/raid1.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+--- a/drivers/md/raid1.c
++++ b/drivers/md/raid1.c
+@@ -445,6 +445,8 @@ static void raid1_end_write_request(stru
+ if (!test_bit(Faulty, &rdev->flags))
+ set_bit(R1BIO_WriteError, &r1_bio->state);
+ else {
++ /* Fail the request */
++ set_bit(R1BIO_Degraded, &r1_bio->state);
+ /* Finished with this branch */
+ r1_bio->bios[mirror] = NULL;
+ to_put = bio;
projects / thirdparty / kernel / stable-queue.git / commitdiff
