+++ /dev/null
-From 02a3307aa9c20b4f6626255b028f07f6cfa16feb Mon Sep 17 00:00:00 2001
-From: Liu Bo <bo.liu@linux.alibaba.com>
-Date: Wed, 16 May 2018 01:37:36 +0800
-Subject: btrfs: fix reading stale metadata blocks after degraded raid1 mounts
-
-From: Liu Bo <bo.liu@linux.alibaba.com>
-
-commit 02a3307aa9c20b4f6626255b028f07f6cfa16feb upstream.
-
-If a btree block, aka. extent buffer, is not available in the extent
-buffer cache, it'll be read out from the disk instead, i.e.
-
-btrfs_search_slot()
- read_block_for_search() # hold parent and its lock, go to read child
- btrfs_release_path()
- read_tree_block() # read child
-
-Unfortunately, the parent lock got released before reading child, so
-commit 5bdd3536cbbe ("Btrfs: Fix block generation verification race") had
-used 0 as parent transid to read the child block. It forces
-read_tree_block() not to check if parent transid is different with the
-generation id of the child that it reads out from disk.
-
-A simple PoC is included in btrfs/124,
-
-0. A two-disk raid1 btrfs,
-
-1. Right after mkfs.btrfs, block A is allocated to be device tree's root.
-
-2. Mount this filesystem and put it in use, after a while, device tree's
- root got COW but block A hasn't been allocated/overwritten yet.
-
-3. Umount it and reload the btrfs module to remove both disks from the
- global @fs_devices list.
-
-4. mount -odegraded dev1 and write some data, so now block A is allocated
- to be a leaf in checksum tree. Note that only dev1 has the latest
- metadata of this filesystem.
-
-5. Umount it and mount it again normally (with both disks), since raid1
- can pick up one disk by the writer task's pid, if btrfs_search_slot()
- needs to read block A, dev2 which does NOT have the latest metadata
- might be read for block A, then we got a stale block A.
-
-6. As parent transid is not checked, block A is marked as uptodate and
- put into the extent buffer cache, so the future search won't bother
- to read disk again, which means it'll make changes on this stale
- one and make it dirty and flush it onto disk.
-
-To avoid the problem, parent transid needs to be passed to
-read_tree_block().
-
-In order to get a valid parent transid, we need to hold the parent's
-lock until finishing reading child.
-
-This patch needs to be slightly adapted for stable kernels, the
-&first_key parameter added to read_tree_block() is from 4.16+
-(581c1760415c4). The fix is to replace 0 by 'gen'.
-
-Fixes: 5bdd3536cbbe ("Btrfs: Fix block generation verification race")
-CC: stable@vger.kernel.org # 4.4+
-Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
-Reviewed-by: Filipe Manana <fdmanana@suse.com>
-Reviewed-by: Qu Wenruo <wqu@suse.com>
-[ update changelog ]
-Signed-off-by: David Sterba <dsterba@suse.com>
-Signed-off-by: Nikolay Borisov <nborisov@suse.com>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- fs/btrfs/ctree.c | 6 +++---
- 1 file changed, 3 insertions(+), 3 deletions(-)
-
---- a/fs/btrfs/ctree.c
-+++ b/fs/btrfs/ctree.c
-@@ -2497,10 +2497,8 @@ read_block_for_search(struct btrfs_trans
- if (p->reada)
- reada_for_search(root, p, level, slot, key->objectid);
-
-- btrfs_release_path(p);
--
- ret = -EAGAIN;
-- tmp = read_tree_block(root, blocknr, 0);
-+ tmp = read_tree_block(fs_info, blocknr, gen);
- if (!IS_ERR(tmp)) {
- /*
- * If the read above didn't mark this buffer up to date,
-@@ -2512,6 +2510,8 @@ read_block_for_search(struct btrfs_trans
- ret = -EIO;
- free_extent_buffer(tmp);
- }
-+
-+ btrfs_release_path(p);
- return ret;
- }
-
arm-8772-1-kprobes-prohibit-kprobes-on-get_user-functions.patch
btrfs-fix-xattr-loss-after-power-failure.patch
btrfs-fix-crash-when-trying-to-resume-balance-without-the-resume-flag.patch
-btrfs-fix-reading-stale-metadata-blocks-after-degraded-raid1-mounts.patch
+++ /dev/null
-From 02a3307aa9c20b4f6626255b028f07f6cfa16feb Mon Sep 17 00:00:00 2001
-From: Liu Bo <bo.liu@linux.alibaba.com>
-Date: Wed, 16 May 2018 01:37:36 +0800
-Subject: btrfs: fix reading stale metadata blocks after degraded raid1 mounts
-
-From: Liu Bo <bo.liu@linux.alibaba.com>
-
-commit 02a3307aa9c20b4f6626255b028f07f6cfa16feb upstream.
-
-If a btree block, aka. extent buffer, is not available in the extent
-buffer cache, it'll be read out from the disk instead, i.e.
-
-btrfs_search_slot()
- read_block_for_search() # hold parent and its lock, go to read child
- btrfs_release_path()
- read_tree_block() # read child
-
-Unfortunately, the parent lock got released before reading child, so
-commit 5bdd3536cbbe ("Btrfs: Fix block generation verification race") had
-used 0 as parent transid to read the child block. It forces
-read_tree_block() not to check if parent transid is different with the
-generation id of the child that it reads out from disk.
-
-A simple PoC is included in btrfs/124,
-
-0. A two-disk raid1 btrfs,
-
-1. Right after mkfs.btrfs, block A is allocated to be device tree's root.
-
-2. Mount this filesystem and put it in use, after a while, device tree's
- root got COW but block A hasn't been allocated/overwritten yet.
-
-3. Umount it and reload the btrfs module to remove both disks from the
- global @fs_devices list.
-
-4. mount -odegraded dev1 and write some data, so now block A is allocated
- to be a leaf in checksum tree. Note that only dev1 has the latest
- metadata of this filesystem.
-
-5. Umount it and mount it again normally (with both disks), since raid1
- can pick up one disk by the writer task's pid, if btrfs_search_slot()
- needs to read block A, dev2 which does NOT have the latest metadata
- might be read for block A, then we got a stale block A.
-
-6. As parent transid is not checked, block A is marked as uptodate and
- put into the extent buffer cache, so the future search won't bother
- to read disk again, which means it'll make changes on this stale
- one and make it dirty and flush it onto disk.
-
-To avoid the problem, parent transid needs to be passed to
-read_tree_block().
-
-In order to get a valid parent transid, we need to hold the parent's
-lock until finishing reading child.
-
-This patch needs to be slightly adapted for stable kernels, the
-&first_key parameter added to read_tree_block() is from 4.16+
-(581c1760415c4). The fix is to replace 0 by 'gen'.
-
-Fixes: 5bdd3536cbbe ("Btrfs: Fix block generation verification race")
-CC: stable@vger.kernel.org # 4.4+
-Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
-Reviewed-by: Filipe Manana <fdmanana@suse.com>
-Reviewed-by: Qu Wenruo <wqu@suse.com>
-[ update changelog ]
-Signed-off-by: David Sterba <dsterba@suse.com>
-Signed-off-by: Nikolay Borisov <nborisov@suse.com>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- fs/btrfs/ctree.c | 6 +++---
- 1 file changed, 3 insertions(+), 3 deletions(-)
-
---- a/fs/btrfs/ctree.c
-+++ b/fs/btrfs/ctree.c
-@@ -2486,10 +2486,8 @@ read_block_for_search(struct btrfs_trans
- if (p->reada != READA_NONE)
- reada_for_search(root, p, level, slot, key->objectid);
-
-- btrfs_release_path(p);
--
- ret = -EAGAIN;
-- tmp = read_tree_block(root, blocknr, 0);
-+ tmp = read_tree_block(fs_info, blocknr, gen);
- if (!IS_ERR(tmp)) {
- /*
- * If the read above didn't mark this buffer up to date,
-@@ -2503,6 +2501,8 @@ read_block_for_search(struct btrfs_trans
- } else {
- ret = PTR_ERR(tmp);
- }
-+
-+ btrfs_release_path(p);
- return ret;
- }
-
btrfs-fix-xattr-loss-after-power-failure.patch
btrfs-fix-crash-when-trying-to-resume-balance-without-the-resume-flag.patch
x86-amd-don-t-set-x86_bug_sysret_ss_attrs-when-running.patch
-btrfs-fix-reading-stale-metadata-blocks-after-degraded-raid1-mounts.patch
projects / thirdparty / kernel / stable-queue.git / commitdiff
