The function will find the root_item specified by the subvol_id, clear the BTRFS_ROOT_SUBVOL_DEAD flag and set root_refs to one.
Signed-off-by: Lu Fengqi <lufq.f...@cn.fujitsu.com> --- ctree.h | 1 + undelete-subvol.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+) diff --git a/ctree.h b/ctree.h index 18f7c79ddeec..3df062cc7c25 100644 --- a/ctree.h +++ b/ctree.h @@ -185,6 +185,7 @@ static int btrfs_csum_sizes[] = { 4 }; #define BTRFS_FT_MAX 9 #define BTRFS_ROOT_SUBVOL_RDONLY (1ULL << 0) +#define BTRFS_ROOT_SUBVOL_DEAD (1ULL << 48) /* * the key defines the order in the tree, and so it also defines (optimal) diff --git a/undelete-subvol.c b/undelete-subvol.c index 00fcc4895778..781057df2b84 100644 --- a/undelete-subvol.c +++ b/undelete-subvol.c @@ -12,6 +12,9 @@ */ #include "ctree.h" +#include "transaction.h" +#include "disk-io.h" +#include "messages.h" /* * Determines whether the subvolume is intact, according to the drop_progress @@ -51,3 +54,55 @@ out: btrfs_release_path(&path); return ret; } + +/* + * Clear BTRFS_ROOT_SUBVOL_DEAD flag and set the root_refs to one. + * + * @root the root of root tree. + * @subvol_id specify the root_item which will be modified. + * + * Return 0 if no error occurred. + */ +static int recover_dead_root(struct btrfs_trans_handle *trans, + struct btrfs_root *root, u64 subvol_id) +{ + struct btrfs_key key; + struct btrfs_path path; + struct extent_buffer *leaf; + struct btrfs_root_item root_item; + u64 root_flags; + u64 offset; + int ret; + + key.objectid = subvol_id; + key.type = BTRFS_ROOT_ITEM_KEY; + key.offset = 0; + + btrfs_init_path(&path); + ret = btrfs_search_slot(trans, root, &key, &path, 0, 0); + if (ret) { + error("couldn't find ROOT_ITEM for %llu failed: %d", + subvol_id, ret); + goto out; + } + + leaf = path.nodes[0]; + + offset = btrfs_item_ptr_offset(leaf, path.slots[0]); + read_extent_buffer(leaf, &root_item, offset, sizeof(root_item)); + + /* Clear BTRFS_ROOT_SUBVOL_DEAD */ + root_flags = btrfs_root_flags(&root_item); + btrfs_set_root_flags(&root_item, + root_flags & ~BTRFS_ROOT_SUBVOL_DEAD); + + /* Increase the refs */ + btrfs_set_root_refs(&root_item, 1); + + write_extent_buffer(leaf, &root_item, offset, sizeof(root_item)); + btrfs_mark_buffer_dirty(leaf); + +out: + btrfs_release_path(&path); + return ret; +} -- 2.16.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html