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-rw-r--r--fs/btrfs/tree-checker.c17
-rw-r--r--include/uapi/linux/btrfs_tree.h14
2 files changed, 26 insertions, 5 deletions
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index 7b1fee630f97..f0ffd5ee77bd 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -1035,7 +1035,7 @@ static int check_root_item(struct extent_buffer *leaf, struct btrfs_key *key,
int slot)
{
struct btrfs_fs_info *fs_info = leaf->fs_info;
- struct btrfs_root_item ri;
+ struct btrfs_root_item ri = { 0 };
const u64 valid_root_flags = BTRFS_ROOT_SUBVOL_RDONLY |
BTRFS_ROOT_SUBVOL_DEAD;
int ret;
@@ -1044,14 +1044,21 @@ static int check_root_item(struct extent_buffer *leaf, struct btrfs_key *key,
if (ret < 0)
return ret;
- if (btrfs_item_size_nr(leaf, slot) != sizeof(ri)) {
+ if (btrfs_item_size_nr(leaf, slot) != sizeof(ri) &&
+ btrfs_item_size_nr(leaf, slot) != btrfs_legacy_root_item_size()) {
generic_err(leaf, slot,
- "invalid root item size, have %u expect %zu",
- btrfs_item_size_nr(leaf, slot), sizeof(ri));
+ "invalid root item size, have %u expect %zu or %u",
+ btrfs_item_size_nr(leaf, slot), sizeof(ri),
+ btrfs_legacy_root_item_size());
}
+ /*
+ * For legacy root item, the members starting at generation_v2 will be
+ * all filled with 0.
+ * And since we allow geneartion_v2 as 0, it will still pass the check.
+ */
read_extent_buffer(leaf, &ri, btrfs_item_ptr_offset(leaf, slot),
- sizeof(ri));
+ btrfs_item_size_nr(leaf, slot));
/* Generation related */
if (btrfs_root_generation(&ri) >
diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
index 9ba64ca6b4ac..6b885982ece6 100644
--- a/include/uapi/linux/btrfs_tree.h
+++ b/include/uapi/linux/btrfs_tree.h
@@ -4,6 +4,11 @@
#include <linux/btrfs.h>
#include <linux/types.h>
+#ifdef __KERNEL__
+#include <linux/stddef.h>
+#else
+#include <stddef.h>
+#endif
/*
* This header contains the structure definitions and constants used
@@ -645,6 +650,15 @@ struct btrfs_root_item {
} __attribute__ ((__packed__));
/*
+ * Btrfs root item used to be smaller than current size. The old format ends
+ * at where member generation_v2 is.
+ */
+static inline __u32 btrfs_legacy_root_item_size(void)
+{
+ return offsetof(struct btrfs_root_item, generation_v2);
+}
+
+/*
* this is used for both forward and backward root refs
*/
struct btrfs_root_ref {