Re: [PATCH 5/8] btrfs-progs: Add btrfs_uuid_tree_remove
From: Qu Wenruo <hidden>
Date: 2021-09-14 01:07:26
On 2021/9/13 下午9:17, Nikolay Borisov wrote:
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It will be used to clear received data on RW snapshots that were received. Signed-off-by: Nikolay Borisov <redacted> --- kernel-shared/ctree.h | 3 ++ kernel-shared/uuid-tree.c | 82 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 85 insertions(+)diff --git a/kernel-shared/ctree.h b/kernel-shared/ctree.h index 91a85796a678..158281a9fd67 100644 --- a/kernel-shared/ctree.h +++ b/kernel-shared/ctree.h@@ -2860,6 +2860,9 @@ int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, u8 *uuid, u8 type, u64 subvol_id_cpu); int btrfs_is_empty_uuid(u8 *uuid); +int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, u8 *uuid, u8 type, + u64 subid); +
I have checked the callers in the incoming check patches, they are all starting a new trans on uuid tree, thus there is no need to start a trans out of this function. Let's just pass the subvolume root into the function, and start a new trans in side the function. So that we only need one parameter @root, everything else can be fetched from @root, and we can also modify the root item and uuid tree just in one go. Thanks, Qu
quoted hunk ↗ jump to hunk
static inline int is_fstree(u64 rootid) {diff --git a/kernel-shared/uuid-tree.c b/kernel-shared/uuid-tree.c index 51a7b5d9ff5d..0f0fbf667dda 100644 --- a/kernel-shared/uuid-tree.c +++ b/kernel-shared/uuid-tree.c@@ -120,3 +120,85 @@ int btrfs_is_empty_uuid(u8 *uuid) } return 1; } + +int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, u8 *uuid, u8 type, + u64 subid) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_root *uuid_root = fs_info->uuid_root; + int ret; + struct btrfs_path *path = NULL; + struct btrfs_key key; + struct extent_buffer *eb; + int slot; + unsigned long offset; + u32 item_size; + unsigned long move_dst; + unsigned long move_src; + unsigned long move_len; + + if (!uuid_root) { + ret = -EINVAL; + goto out; + } + + btrfs_uuid_to_key(uuid, &key); + key.type = type; + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1); + if (ret < 0) { + warning("error %d while searching for uuid item!", ret); + goto out; + } + if (ret > 0) { + ret = -ENOENT; + goto out; + } + + + eb = path->nodes[0]; + slot = path->slots[0]; + offset = btrfs_item_ptr_offset(eb, slot); + item_size = btrfs_item_size_nr(eb, slot); + if (!IS_ALIGNED(item_size, sizeof(u64))) { + warning("uuid item with illegal size %lu!", (unsigned long)item_size); + ret = -ENOENT; + goto out; + } + while (item_size) { + __le64 read_subid; + + read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid)); + if (le64_to_cpu(read_subid) == subid) + break; + offset += sizeof(read_subid); + item_size -= sizeof(read_subid); + } + + if (!item_size) { + ret = -ENOENT; + goto out; + } + + item_size = btrfs_item_size_nr(eb, slot); + if (item_size == sizeof(subid)) { + ret = btrfs_del_item(trans, uuid_root, path); + goto out; + } + + move_dst = offset; + move_src = offset + sizeof(subid); + move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot)); + memmove_extent_buffer(eb, move_dst, move_src, move_len); + btrfs_truncate_item(path, item_size - sizeof(subid), 1); + +out: + btrfs_free_path(path); + return ret; +}