From: Qu Wenruo <wqu@suse.com>
To: linux-btrfs@vger.kernel.org
Cc: Zhenyu Wu <wuzy001@gmail.com>
Subject: [PATCH v4] btrfs: rescue: allow ibadroots to skip bad extent tree when reading block group items
Date: Mon, 19 Jul 2021 13:43:04 +0800 [thread overview]
Message-ID: <20210719054304.181509-1-wqu@suse.com> (raw)
When extent tree gets corrupted, normally it's not extent tree root, but
one toasted tree leaf/node.
In that case, rescue=ibadroots mount option won't help as it can only
handle the extent tree root corruption.
This patch will enhance the behavior by:
- Allow fill_dummy_bgs() to ignore -EEXIST error
This means we may have some block group items read from disk, but
then hit some error halfway.
- Fallback to fill_dummy_bgs() if any error gets hit in
btrfs_read_block_groups()
Of course, this still needs rescue=ibadroots mount option.
With that, rescue=ibadroots can handle extent tree corruption more
gracefully and allow a better recover chance.
Reported-by: Zhenyu Wu <wuzy001@gmail.com>
Link: https://www.spinics.net/lists/linux-btrfs/msg114424.html
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
Changelog:
v2:
- Don't try to fill with dummy block groups when we hit ENOMEM
v3:
- Remove a dead condition
The empty fs_info->extent_root case has already been handled.
v4:
- Skip to next block group if we hit EEXIST when inserting the block
group cache
---
fs/btrfs/block-group.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 5bd76a45037e..758ba856f8c6 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -2105,11 +2105,22 @@ static int fill_dummy_bgs(struct btrfs_fs_info *fs_info)
bg->used = em->len;
bg->flags = map->type;
ret = btrfs_add_block_group_cache(fs_info, bg);
+ /*
+ * We may have some valid block group cache added already, in
+ * that case we skip to next bg.
+ */
+ if (ret == -EEXIST) {
+ ret = 0;
+ btrfs_put_block_group(bg);
+ continue;
+ }
+
if (ret) {
btrfs_remove_free_space_cache(bg);
btrfs_put_block_group(bg);
break;
}
+
btrfs_update_space_info(fs_info, bg->flags, em->len, em->len,
0, 0, &space_info);
bg->space_info = space_info;
@@ -2212,6 +2223,14 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info)
ret = check_chunk_block_group_mappings(info);
error:
btrfs_free_path(path);
+ /*
+ * We hit some error reading the extent tree, and have rescue=ibadroots
+ * mount option.
+ * Try to fill using dummy block groups so that the user can continue
+ * to mount and grab their data.
+ */
+ if (ret && btrfs_test_opt(info, IGNOREBADROOTS))
+ ret = fill_dummy_bgs(info);
return ret;
}
--
2.32.0
next reply other threads:[~2021-07-19 5:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-19 5:43 Qu Wenruo [this message]
2021-07-19 5:52 ` [PATCH v4] btrfs: rescue: allow ibadroots to skip bad extent tree when reading block group items Su Yue
2021-07-19 8:19 ` Anand Jain
2021-07-21 17:33 ` David Sterba
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