--- /dev/null
+From Alexander.Levin@microsoft.com Mon Jun 18 06:35:35 2018
+From: Sasha Levin <Alexander.Levin@microsoft.com>
+Date: Fri, 15 Jun 2018 02:39:02 +0000
+Subject: Btrfs: fix scrub to repair raid6 corruption
+To: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
+Cc: "ben.hutchings@codethink.co.uk" <ben.hutchings@codethink.co.uk>, "stable@vger.kernel.org" <stable@vger.kernel.org>, Liu Bo <bo.li.liu@oracle.com>, David Sterba <dsterba@suse.com>, Sasha Levin <Alexander.Levin@microsoft.com>
+Message-ID: <20180615023842.99130-2-alexander.levin@microsoft.com>
+
+
+From: Liu Bo <bo.li.liu@oracle.com>
+
+[ Upstream commit 762221f095e3932669093466aaf4b85ed9ad2ac1 ]
+
+The raid6 corruption is that,
+suppose that all disks can be read without problems and if the content
+that was read out doesn't match its checksum, currently for raid6
+btrfs at most retries twice,
+
+- the 1st retry is to rebuild with all other stripes, it'll eventually
+ be a raid5 xor rebuild,
+- if the 1st fails, the 2nd retry will deliberately fail parity p so
+ that it will do raid6 style rebuild,
+
+however, the chances are that another non-parity stripe content also
+has something corrupted, so that the above retries are not able to
+return correct content.
+
+We've fixed normal reads to rebuild raid6 correctly with more retries
+in Patch "Btrfs: make raid6 rebuild retry more"[1], this is to fix
+scrub to do the exactly same rebuild process.
+
+[1]: https://patchwork.kernel.org/patch/10091755/
+
+Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
+Signed-off-by: David Sterba <dsterba@suse.com>
+Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/btrfs/scrub.c | 44 ++++++++++++++++++++++++++++++++------------
+ 1 file changed, 32 insertions(+), 12 deletions(-)
+
+--- a/fs/btrfs/scrub.c
++++ b/fs/btrfs/scrub.c
+@@ -301,6 +301,11 @@ static void __scrub_blocked_if_needed(st
+ static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
+ static void scrub_put_ctx(struct scrub_ctx *sctx);
+
++static inline int scrub_is_page_on_raid56(struct scrub_page *page)
++{
++ return page->recover &&
++ (page->recover->bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK);
++}
+
+ static void scrub_pending_bio_inc(struct scrub_ctx *sctx)
+ {
+@@ -1323,15 +1328,34 @@ nodatasum_case:
+ * could happen otherwise that a correct page would be
+ * overwritten by a bad one).
+ */
+- for (mirror_index = 0;
+- mirror_index < BTRFS_MAX_MIRRORS &&
+- sblocks_for_recheck[mirror_index].page_count > 0;
+- mirror_index++) {
++ for (mirror_index = 0; ;mirror_index++) {
+ struct scrub_block *sblock_other;
+
+ if (mirror_index == failed_mirror_index)
+ continue;
+- sblock_other = sblocks_for_recheck + mirror_index;
++
++ /* raid56's mirror can be more than BTRFS_MAX_MIRRORS */
++ if (!scrub_is_page_on_raid56(sblock_bad->pagev[0])) {
++ if (mirror_index >= BTRFS_MAX_MIRRORS)
++ break;
++ if (!sblocks_for_recheck[mirror_index].page_count)
++ break;
++
++ sblock_other = sblocks_for_recheck + mirror_index;
++ } else {
++ struct scrub_recover *r = sblock_bad->pagev[0]->recover;
++ int max_allowed = r->bbio->num_stripes -
++ r->bbio->num_tgtdevs;
++
++ if (mirror_index >= max_allowed)
++ break;
++ if (!sblocks_for_recheck[1].page_count)
++ break;
++
++ ASSERT(failed_mirror_index == 0);
++ sblock_other = sblocks_for_recheck + 1;
++ sblock_other->pagev[0]->mirror_num = 1 + mirror_index;
++ }
+
+ /* build and submit the bios, check checksums */
+ scrub_recheck_block(fs_info, sblock_other, 0);
+@@ -1679,18 +1703,13 @@ static void scrub_bio_wait_endio(struct
+ complete(&ret->event);
+ }
+
+-static inline int scrub_is_page_on_raid56(struct scrub_page *page)
+-{
+- return page->recover &&
+- (page->recover->bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK);
+-}
+-
+ static int scrub_submit_raid56_bio_wait(struct btrfs_fs_info *fs_info,
+ struct bio *bio,
+ struct scrub_page *page)
+ {
+ struct scrub_bio_ret done;
+ int ret;
++ int mirror_num;
+
+ init_completion(&done.event);
+ done.status = 0;
+@@ -1698,9 +1717,10 @@ static int scrub_submit_raid56_bio_wait(
+ bio->bi_private = &done;
+ bio->bi_end_io = scrub_bio_wait_endio;
+
++ mirror_num = page->sblock->pagev[0]->mirror_num;
+ ret = raid56_parity_recover(fs_info, bio, page->recover->bbio,
+ page->recover->map_length,
+- page->mirror_num, 0);
++ mirror_num, 0);
+ if (ret)
+ return ret;
+
--- /dev/null
+From Alexander.Levin@microsoft.com Mon Jun 18 06:35:49 2018
+From: Sasha Levin <Alexander.Levin@microsoft.com>
+Date: Fri, 15 Jun 2018 02:39:04 +0000
+Subject: Btrfs: make raid6 rebuild retry more
+To: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
+Cc: "ben.hutchings@codethink.co.uk" <ben.hutchings@codethink.co.uk>, "stable@vger.kernel.org" <stable@vger.kernel.org>, Liu Bo <bo.li.liu@oracle.com>, David Sterba <dsterba@suse.com>, Sasha Levin <Alexander.Levin@microsoft.com>
+Message-ID: <20180615023842.99130-3-alexander.levin@microsoft.com>
+
+
+From: Liu Bo <bo.li.liu@oracle.com>
+
+[ Upstream commit 8810f7517a3bc4ca2d41d022446d3f5fd6b77c09 ]
+
+There is a scenario that can end up with rebuild process failing to
+return good content, i.e.
+suppose that all disks can be read without problems and if the content
+that was read out doesn't match its checksum, currently for raid6
+btrfs at most retries twice,
+
+- the 1st retry is to rebuild with all other stripes, it'll eventually
+ be a raid5 xor rebuild,
+- if the 1st fails, the 2nd retry will deliberately fail parity p so
+ that it will do raid6 style rebuild,
+
+however, the chances are that another non-parity stripe content also
+has something corrupted, so that the above retries are not able to
+return correct content, and users will think of this as data loss.
+More seriouly, if the loss happens on some important internal btree
+roots, it could refuse to mount.
+
+This extends btrfs to do more retries and each retry fails only one
+stripe. Since raid6 can tolerate 2 disk failures, if there is one
+more failure besides the failure on which we're recovering, this can
+always work.
+
+The worst case is to retry as many times as the number of raid6 disks,
+but given the fact that such a scenario is really rare in practice,
+it's still acceptable.
+
+Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
+Signed-off-by: David Sterba <dsterba@suse.com>
+Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/btrfs/raid56.c | 18 ++++++++++++++----
+ fs/btrfs/volumes.c | 9 ++++++++-
+ 2 files changed, 22 insertions(+), 5 deletions(-)
+
+--- a/fs/btrfs/raid56.c
++++ b/fs/btrfs/raid56.c
+@@ -2172,11 +2172,21 @@ int raid56_parity_recover(struct btrfs_f
+ }
+
+ /*
+- * reconstruct from the q stripe if they are
+- * asking for mirror 3
++ * Loop retry:
++ * for 'mirror == 2', reconstruct from all other stripes.
++ * for 'mirror_num > 2', select a stripe to fail on every retry.
+ */
+- if (mirror_num == 3)
+- rbio->failb = rbio->real_stripes - 2;
++ if (mirror_num > 2) {
++ /*
++ * 'mirror == 3' is to fail the p stripe and
++ * reconstruct from the q stripe. 'mirror > 3' is to
++ * fail a data stripe and reconstruct from p+q stripe.
++ */
++ rbio->failb = rbio->real_stripes - (mirror_num - 1);
++ ASSERT(rbio->failb > 0);
++ if (rbio->failb <= rbio->faila)
++ rbio->failb--;
++ }
+
+ ret = lock_stripe_add(rbio);
+
+--- a/fs/btrfs/volumes.c
++++ b/fs/btrfs/volumes.c
+@@ -5110,7 +5110,14 @@ int btrfs_num_copies(struct btrfs_fs_inf
+ else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
+ ret = 2;
+ else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
+- ret = 3;
++ /*
++ * There could be two corrupted data stripes, we need
++ * to loop retry in order to rebuild the correct data.
++ *
++ * Fail a stripe at a time on every retry except the
++ * stripe under reconstruction.
++ */
++ ret = map->num_stripes;
+ else
+ ret = 1;
+ free_extent_map(em);
--- /dev/null
+From Alexander.Levin@microsoft.com Mon Jun 18 06:35:07 2018
+From: Sasha Levin <Alexander.Levin@microsoft.com>
+Date: Fri, 15 Jun 2018 02:39:01 +0000
+Subject: Revert "Btrfs: fix scrub to repair raid6 corruption"
+To: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
+Cc: "ben.hutchings@codethink.co.uk" <ben.hutchings@codethink.co.uk>, "stable@vger.kernel.org" <stable@vger.kernel.org>, Sasha Levin <Alexander.Levin@microsoft.com>
+Message-ID: <20180615023842.99130-1-alexander.levin@microsoft.com>
+
+From: Sasha Levin <Alexander.Levin@microsoft.com>
+
+This reverts commit d91bb7c6988bd6450284c762b33f2e1ea3fe7c97.
+
+This commit used an incorrect log message.
+
+Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
+Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/btrfs/raid56.c | 18 ++++--------------
+ fs/btrfs/volumes.c | 9 +--------
+ 2 files changed, 5 insertions(+), 22 deletions(-)
+
+--- a/fs/btrfs/raid56.c
++++ b/fs/btrfs/raid56.c
+@@ -2172,21 +2172,11 @@ int raid56_parity_recover(struct btrfs_f
+ }
+
+ /*
+- * Loop retry:
+- * for 'mirror == 2', reconstruct from all other stripes.
+- * for 'mirror_num > 2', select a stripe to fail on every retry.
++ * reconstruct from the q stripe if they are
++ * asking for mirror 3
+ */
+- if (mirror_num > 2) {
+- /*
+- * 'mirror == 3' is to fail the p stripe and
+- * reconstruct from the q stripe. 'mirror > 3' is to
+- * fail a data stripe and reconstruct from p+q stripe.
+- */
+- rbio->failb = rbio->real_stripes - (mirror_num - 1);
+- ASSERT(rbio->failb > 0);
+- if (rbio->failb <= rbio->faila)
+- rbio->failb--;
+- }
++ if (mirror_num == 3)
++ rbio->failb = rbio->real_stripes - 2;
+
+ ret = lock_stripe_add(rbio);
+
+--- a/fs/btrfs/volumes.c
++++ b/fs/btrfs/volumes.c
+@@ -5110,14 +5110,7 @@ int btrfs_num_copies(struct btrfs_fs_inf
+ else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
+ ret = 2;
+ else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
+- /*
+- * There could be two corrupted data stripes, we need
+- * to loop retry in order to rebuild the correct data.
+- *
+- * Fail a stripe at a time on every retry except the
+- * stripe under reconstruction.
+- */
+- ret = map->num_stripes;
++ ret = 3;
+ else
+ ret = 1;
+ free_extent_map(em);
arm-8753-1-decompressor-add-a-missing-parameter-to-the-addruart-macro.patch
arm-8758-1-decompressor-restore-r1-and-r2-just-before-jumping-to-the-kernel.patch
arm-kexec-fix-kdump-register-saving-on-panic.patch
+revert-btrfs-fix-scrub-to-repair-raid6-corruption.patch
+btrfs-fix-scrub-to-repair-raid6-corruption.patch
+btrfs-make-raid6-rebuild-retry-more.patch
projects / thirdparty / kernel / stable-queue.git / commitdiff
