When lowmem fsck tries to find backref of a specified file extent, it
searches inlined data ref first.
However, extent data ref contains owner root objectid, inode number
and calculated offset (file offset - extent offset).
The code only checks owner root objectid, not checking inode number nor
calculated offset.
This makes lowmem mode fails to detect any backref mismatch if there is
a inlined data ref with the same owner objectid.
Fix it by also checking extent data ref's objectid and offset.
Fixes: b0d360b541f0 ("btrfs-progs: check: introduce function to check data backref in extent tree")
Reported-by: Chris Murphy <chris@xxxxxxxxxxxxxxxxx>
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
cmds-check.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/cmds-check.c b/cmds-check.c
index 5c822b848608..0ceff5b7bbea 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -10411,11 +10411,11 @@ static int check_extent_data_item(struct btrfs_root *root,
u64 disk_num_bytes;
u64 extent_num_bytes;
u64 extent_flags;
+ u64 offset;
u32 item_size;
unsigned long end;
unsigned long ptr;
int type;
- u64 ref_root;
int found_dbackref = 0;
int err = 0;
int ret;
@@ -10431,6 +10431,7 @@ static int check_extent_data_item(struct btrfs_root *root,
disk_bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
disk_num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
extent_num_bytes = btrfs_file_extent_num_bytes(eb, fi);
+ offset = btrfs_file_extent_offset(eb, fi);
/* Check unaligned disk_num_bytes and num_bytes */
if (!IS_ALIGNED(disk_num_bytes, root->fs_info->sectorsize)) {
@@ -10483,13 +10484,22 @@ static int check_extent_data_item(struct btrfs_root *root,
ptr = (unsigned long)iref;
end = (unsigned long)ei + item_size;
while (ptr < end) {
+ u64 ref_root;
+ u64 ref_objectid;
+ u64 ref_offset;
+
iref = (struct btrfs_extent_inline_ref *)ptr;
type = btrfs_extent_inline_ref_type(leaf, iref);
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
ref_root = btrfs_extent_data_ref_root(leaf, dref);
- if (ref_root == owner || ref_root == root->objectid)
+ ref_objectid = btrfs_extent_data_ref_objectid(leaf, dref);
+ ref_offset = btrfs_extent_data_ref_offset(leaf, dref);
+
+ if ((ref_root == owner || ref_root == root->objectid) &&
+ ref_objectid == fi_key.objectid &&
+ ref_offset == fi_key.offset - offset)
found_dbackref = 1;
} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
found_dbackref = !check_tree_block_ref(root, NULL,
--
2.15.0
--
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