[gentoo-commits] proj/linux-patches:6.0 commit in: /

[Mike Pagano]

commit:     5ceffccd28e7d4cc987afb63c276189d7d3925e0
Author:     Mike Pagano <mpagano <AT> gentoo <DOT> org>
AuthorDate: Tue Nov  1 12:45:24 2022 +0000
Commit:     Mike Pagano <mpagano <AT> gentoo <DOT> org>
CommitDate: Tue Nov  1 12:45:24 2022 +0000
URL:        https://gitweb.gentoo.org/proj/linux-patches.git/commit/?id=5ceffccd

btrfs: don't use btrfs_chunk::sub_stripes from disk

Bug: https://bugs.gentoo.org/878023

Signed-off-by: Mike Pagano <mpagano <AT> gentoo.org>

 0000_README                            |  8 ++-
 1900_btrfs-chunk-sub_stripes-fix.patch | 92 ++++++++++++++++++++++++++++++++++
 2 files changed, 98 insertions(+), 2 deletions(-)

diff --git a/0000_README b/0000_README
index 68ada3e5..a0b5ecc7 100644
--- a/0000_README
+++ b/0000_README
@@ -76,8 +76,12 @@ From:   http://sources.debian.net/src/linux/3.16.7-ckt4-3/debian/patches/debian/
 Desc:   Enable link security restrictions by default.
 
 Patch:  1700_sparc-address-warray-bound-warnings.patch
-From:	https://github.com/KSPP/linux/issues/109
-Desc:	Address -Warray-bounds warnings 
+From:		https://github.com/KSPP/linux/issues/109
+Desc:		Address -Warray-bounds warnings 
+
+Patch:  1900_btrfs-chunk-sub_stripes-fix.patch
+From:		https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
+Desc:		btrfs: Don't use btrfs_chunk::sub_stripes from disk
 
 Patch:  2000_BT-Check-key-sizes-only-if-Secure-Simple-Pairing-enabled.patch
 From:   https://lore.kernel.org/linux-bluetooth/20190522070540.48895-1-marcel@××××××××.org/raw

diff --git a/1900_btrfs-chunk-sub_stripes-fix.patch b/1900_btrfs-chunk-sub_stripes-fix.patch
new file mode 100644
index 00000000..2ffe02fe
--- /dev/null
+++ b/1900_btrfs-chunk-sub_stripes-fix.patch
@@ -0,0 +1,92 @@
+From 76a66ba101329316a5d7f4275070be22eb85fdf2 Mon Sep 17 00:00:00 2001
+From: Qu Wenruo <wqu@××××.com>
+Date: Fri, 21 Oct 2022 08:43:45 +0800
+Subject: btrfs: don't use btrfs_chunk::sub_stripes from disk
+
+[BUG]
+There are two reports (the earliest one from LKP, a more recent one from
+kernel bugzilla) that we can have some chunks with 0 as sub_stripes.
+
+This will cause divide-by-zero errors at btrfs_rmap_block, which is
+introduced by a recent kernel patch ac0677348f3c ("btrfs: merge
+calculations for simple striped profiles in btrfs_rmap_block"):
+
+		if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
+				 BTRFS_BLOCK_GROUP_RAID10)) {
+			stripe_nr = stripe_nr * map->num_stripes + i;
+			stripe_nr = div_u64(stripe_nr, map->sub_stripes); <<<
+		}
+
+[CAUSE]
+From the more recent report, it has been proven that we have some chunks
+with 0 as sub_stripes, mostly caused by older mkfs.
+
+It turns out that the mkfs.btrfs fix is only introduced in 6718ab4d33aa
+("btrfs-progs: Initialize sub_stripes to 1 in btrfs_alloc_data_chunk")
+which is included in v5.4 btrfs-progs release.
+
+So there would be quite some old filesystems with such 0 sub_stripes.
+
+[FIX]
+Just don't trust the sub_stripes values from disk.
+
+We have a trusted btrfs_raid_array[] to fetch the correct sub_stripes
+numbers for each profile and that are fixed.
+
+By this, we can keep the compatibility with older filesystems while
+still avoid divide-by-zero bugs.
+
+Reported-by: kernel test robot <oliver.sang@×××××.com>
+Reported-by: Viktor Kuzmin <kvaster@×××××.com>
+Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216559
+Fixes: ac0677348f3c ("btrfs: merge calculations for simple striped profiles in btrfs_rmap_block")
+CC: stable@×××××××××××.org # 6.0
+Reviewed-by: Su Yue <glass@××××××.io>
+Reviewed-by: Johannes Thumshirn <johannes.thumshirn@×××.com>
+Signed-off-by: Qu Wenruo <wqu@××××.com>
+Signed-off-by: David Sterba <dsterba@××××.com>
+---
+ fs/btrfs/volumes.c | 12 +++++++++++-
+ 1 file changed, 11 insertions(+), 1 deletion(-)
+
+(limited to 'fs/btrfs/volumes.c')
+
+diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
+index 94ba46d579205..a8d4bc6a19379 100644
+--- a/fs/btrfs/volumes.c
++++ b/fs/btrfs/volumes.c
+@@ -7142,6 +7142,7 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
+ 	u64 devid;
+ 	u64 type;
+ 	u8 uuid[BTRFS_UUID_SIZE];
++	int index;
+ 	int num_stripes;
+ 	int ret;
+ 	int i;
+@@ -7149,6 +7150,7 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
+ 	logical = key->offset;
+ 	length = btrfs_chunk_length(leaf, chunk);
+ 	type = btrfs_chunk_type(leaf, chunk);
++	index = btrfs_bg_flags_to_raid_index(type);
+ 	num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
+ 
+ #if BITS_PER_LONG == 32
+@@ -7202,7 +7204,15 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
+ 	map->io_align = btrfs_chunk_io_align(leaf, chunk);
+ 	map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
+ 	map->type = type;
+-	map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
++	/*
++	 * We can't use the sub_stripes value, as for profiles other than
++	 * RAID10, they may have 0 as sub_stripes for filesystems created by
++	 * older mkfs (<v5.4).
++	 * In that case, it can cause divide-by-zero errors later.
++	 * Since currently sub_stripes is fixed for each profile, let's
++	 * use the trusted value instead.
++	 */
++	map->sub_stripes = btrfs_raid_array[index].sub_stripes;
+ 	map->verified_stripes = 0;
+ 	em->orig_block_len = btrfs_calc_stripe_length(em);
+ 	for (i = 0; i < num_stripes; i++) {
+-- 
+cgit