6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Qu Wenruo <wqu@xxxxxxxx>
commit dfb92681a19e1d5172420baa242806414b3eff6f upstream.
[BUG]
There is a bug report in the mailing list where btrfs_run_delayed_refs()
failed to drop the ref count for logical 25870311358464 num_bytes
2113536.
The involved leaf dump looks like this:
item 166 key (25870311358464 168 2113536) itemoff 10091 itemsize 50
extent refs 1 gen 84178 flags 1
ref#0: shared data backref parent 32399126528000 count 0 <<<
ref#1: shared data backref parent 31808973717504 count 1
Notice the count number is 0.
[CAUSE]
There is no concrete evidence yet, but considering 0 -> 1 is also a
single bit flipped, it's possible that hardware memory bitflip is
involved, causing the on-disk extent tree to be corrupted.
[FIX]
To prevent us reading such corrupted extent item, or writing such
damaged extent item back to disk, enhance the handling of
BTRFS_EXTENT_DATA_REF_KEY and BTRFS_SHARED_DATA_REF_KEY keys for both
inlined and key items, to detect such 0 ref count and reject them.
CC: stable@xxxxxxxxxxxxxxx # 5.4+
Link: https://lore.kernel.org/linux-btrfs/7c69dd49-c346-4806-86e7-e6f863a66f48@xxxxxxxxxxxxxxxx/
Reported-by: Frankie Fisher <frankie@xxxxxxxxxxxxxxx>
Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx>
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/tree-checker.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -1503,6 +1503,11 @@ static int check_extent_item(struct exte
dref_offset, fs_info->sectorsize);
return -EUCLEAN;
}
+ if (unlikely(btrfs_extent_data_ref_count(leaf, dref) == 0)) {
+ extent_err(leaf, slot,
+ "invalid data ref count, should have non-zero value");
+ return -EUCLEAN;
+ }
inline_refs += btrfs_extent_data_ref_count(leaf, dref);
break;
/* Contains parent bytenr and ref count */
@@ -1515,6 +1520,11 @@ static int check_extent_item(struct exte
inline_offset, fs_info->sectorsize);
return -EUCLEAN;
}
+ if (unlikely(btrfs_shared_data_ref_count(leaf, sref) == 0)) {
+ extent_err(leaf, slot,
+ "invalid shared data ref count, should have non-zero value");
+ return -EUCLEAN;
+ }
inline_refs += btrfs_shared_data_ref_count(leaf, sref);
break;
default:
@@ -1584,8 +1594,18 @@ static int check_simple_keyed_refs(struc
{
u32 expect_item_size = 0;
- if (key->type == BTRFS_SHARED_DATA_REF_KEY)
+ if (key->type == BTRFS_SHARED_DATA_REF_KEY) {
+ struct btrfs_shared_data_ref *sref;
+
+ sref = btrfs_item_ptr(leaf, slot, struct btrfs_shared_data_ref);
+ if (unlikely(btrfs_shared_data_ref_count(leaf, sref) == 0)) {
+ extent_err(leaf, slot,
+ "invalid shared data backref count, should have non-zero value");
+ return -EUCLEAN;
+ }
+
expect_item_size = sizeof(struct btrfs_shared_data_ref);
+ }
if (unlikely(btrfs_item_size(leaf, slot) != expect_item_size)) {
generic_err(leaf, slot,
@@ -1662,6 +1682,11 @@ static int check_extent_data_ref(struct
offset, leaf->fs_info->sectorsize);
return -EUCLEAN;
}
+ if (unlikely(btrfs_extent_data_ref_count(leaf, dref) == 0)) {
+ extent_err(leaf, slot,
+ "invalid extent data backref count, should have non-zero value");
+ return -EUCLEAN;
+ }
}
return 0;
}
