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authorStefan Behrens <sbehrens@giantdisaster.de>2013-08-15 17:11:23 +0200
committerChris Mason <chris.mason@fusionio.com>2013-09-01 08:15:58 -0400
commit70f801754728017ebc909d603c69255dc1e6f06f (patch)
treef4af464776a17b130686cb85a98adbeb6083d43c /fs/btrfs/uuid-tree.c
parent26432799c902b76e87f68f5c88f2146a78ba84af (diff)
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Btrfs: check UUID tree during mount if required
If the filesystem was mounted with an old kernel that was not aware of the UUID tree, this is detected by looking at the uuid_tree_generation field of the superblock (similar to how the free space cache is doing it). If a mismatch is detected at mount time, a thread is started that does two things: 1. Iterate through the UUID tree, check each entry, delete those entries that are not valid anymore (i.e., the subvol does not exist anymore or the value changed). 2. Iterate through the root tree, for each found subvolume, add the UUID tree entries for the subvolume (if they are not already there). This mechanism is also used to handle and repair errors that happened during the initial creation and filling of the tree. The update of the uuid_tree_generation field (which indicates that the state of the UUID tree is up to date) is blocked until all create and repair operations are successfully completed. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'fs/btrfs/uuid-tree.c')
-rw-r--r--fs/btrfs/uuid-tree.c123
1 files changed, 123 insertions, 0 deletions
diff --git a/fs/btrfs/uuid-tree.c b/fs/btrfs/uuid-tree.c
index 04a04fa0f7c4..dd0dea3766f7 100644
--- a/fs/btrfs/uuid-tree.c
+++ b/fs/btrfs/uuid-tree.c
@@ -233,3 +233,126 @@ out:
btrfs_free_path(path);
return ret;
}
+
+static int btrfs_uuid_iter_rem(struct btrfs_root *uuid_root, u8 *uuid, u8 type,
+ u64 subid)
+{
+ struct btrfs_trans_handle *trans;
+ int ret;
+
+ /* 1 - for the uuid item */
+ trans = btrfs_start_transaction(uuid_root, 1);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out;
+ }
+
+ ret = btrfs_uuid_tree_rem(trans, uuid_root, uuid, type, subid);
+ btrfs_end_transaction(trans, uuid_root);
+
+out:
+ return ret;
+}
+
+int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info,
+ int (*check_func)(struct btrfs_fs_info *, u8 *, u8,
+ u64))
+{
+ struct btrfs_root *root = fs_info->uuid_root;
+ struct btrfs_key key;
+ struct btrfs_key max_key;
+ struct btrfs_path *path;
+ int ret = 0;
+ struct extent_buffer *leaf;
+ int slot;
+ u32 item_size;
+ unsigned long offset;
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ key.objectid = 0;
+ key.type = 0;
+ key.offset = 0;
+ max_key.objectid = (u64)-1;
+ max_key.type = (u8)-1;
+ max_key.offset = (u64)-1;
+
+again_search_slot:
+ path->keep_locks = 1;
+ ret = btrfs_search_forward(root, &key, &max_key, path, 0);
+ if (ret) {
+ if (ret > 0)
+ ret = 0;
+ goto out;
+ }
+
+ while (1) {
+ cond_resched();
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+
+ if (key.type != BTRFS_UUID_KEY_SUBVOL &&
+ key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
+ goto skip;
+
+ offset = btrfs_item_ptr_offset(leaf, slot);
+ item_size = btrfs_item_size_nr(leaf, slot);
+ if (!IS_ALIGNED(item_size, sizeof(u64))) {
+ pr_warn("btrfs: uuid item with illegal size %lu!\n",
+ (unsigned long)item_size);
+ goto skip;
+ }
+ while (item_size) {
+ u8 uuid[BTRFS_UUID_SIZE];
+ __le64 subid_le;
+ u64 subid_cpu;
+
+ put_unaligned_le64(key.objectid, uuid);
+ put_unaligned_le64(key.offset, uuid + sizeof(u64));
+ read_extent_buffer(leaf, &subid_le, offset,
+ sizeof(subid_le));
+ subid_cpu = le64_to_cpu(subid_le);
+ ret = check_func(fs_info, uuid, key.type, subid_cpu);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ btrfs_release_path(path);
+ ret = btrfs_uuid_iter_rem(root, uuid, key.type,
+ subid_cpu);
+ if (ret == 0) {
+ /*
+ * this might look inefficient, but the
+ * justification is that it is an
+ * exception that check_func returns 1,
+ * and that in the regular case only one
+ * entry per UUID exists.
+ */
+ goto again_search_slot;
+ }
+ if (ret < 0 && ret != -ENOENT)
+ goto out;
+ }
+ item_size -= sizeof(subid_le);
+ offset += sizeof(subid_le);
+ }
+
+skip:
+ ret = btrfs_next_item(root, path);
+ if (ret == 0)
+ continue;
+ else if (ret > 0)
+ ret = 0;
+ break;
+ }
+
+out:
+ btrfs_free_path(path);
+ if (ret)
+ pr_warn("btrfs: btrfs_uuid_tree_iterate failed %d\n", ret);
+ return 0;
+}