On 12/27/18 3:13 PM, Qu Wenruo wrote:
Although we have btrfs_uuid_tree_lookup_any(), it's an online function
utilizing tree search ioctl, not an offline search function.
This patch will port kernel btrfs_uuid_tree_lookup() into btrfs-progs
for later proper uuid tree initialization.
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
One nitpick bellow.
Reviewed-by: Su Yue <damenly_su@xxxxxxx>
---
uuid-tree.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 69 insertions(+), 2 deletions(-)
diff --git a/uuid-tree.c b/uuid-tree.c
index 320eb67e1404..b9190103c355 100644
--- a/uuid-tree.c
+++ b/uuid-tree.c
@@ -23,6 +23,7 @@
#include "transaction.h"
#include "disk-io.h"
#include "print-tree.h"
+#include "utils.h"
static void btrfs_uuid_to_key(const u8 *uuid, u64 *key_objectid,
@@ -32,8 +33,11 @@ static void btrfs_uuid_to_key(const u8 *uuid, u64 *key_objectid,
*key_offset = get_unaligned_le64(uuid + sizeof(u64));
}
-
-/* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
+/*
+ * Search uuid tree of a *MOUNTED* btrfs (online)
+ *
+ * return -ENOENT for !found, < 0 for errors, or 0 if an item was found
+ */
static int btrfs_uuid_tree_lookup_any(int fd, const u8 *uuid, u8 type,
u64 *subid)
{
@@ -103,3 +107,66 @@ int btrfs_lookup_uuid_received_subvol_item(int fd, const u8 *uuid,
BTRFS_UUID_KEY_RECEIVED_SUBVOL,
subvol_id);
}
+
+/*
+ * Search uuid tree of an *UNMOUNTED* btrfs (offline)
For consistency of btrfs_uuid_tree_lookup_any(), I'd like to add
"> + * return -ENOENT for !found, < 0 for errors, or 0 if an item was found"
here too :).
+ */
+static int btrfs_uuid_tree_lookup(struct btrfs_root *uuid_root, u8 *uuid,
+ u8 type, u64 subid)
+{
+ int ret;
+ struct btrfs_path *path = NULL;
+ struct extent_buffer *eb;
+ int slot;
+ u32 item_size;
+ unsigned long offset;
+ struct btrfs_key key;
+
+ if (!uuid_root) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ btrfs_uuid_to_key(uuid, &key.objectid, &key.offset);
+ key.type = type;
+ ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
+ if (ret < 0) {
+ goto out;
+ } else if (ret > 0) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ item_size = btrfs_item_size_nr(eb, slot);
+ offset = btrfs_item_ptr_offset(eb, slot);
+ ret = -ENOENT;
+
+ if (!IS_ALIGNED(item_size, sizeof(u64))) {
+ warning("uuid item with illegal size %lu!",
+ (unsigned long)item_size);
+ goto out;
+ }
+ while (item_size) {
+ __le64 data;
+
+ read_extent_buffer(eb, &data, offset, sizeof(data));
+ if (le64_to_cpu(data) == subid) {
+ ret = 0;
+ break;
+ }
+ offset += sizeof(data);
+ item_size -= sizeof(data);
+ }
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
