diff options
author | Qu Wenruo <wqu@suse.com> | 2022-03-11 10:38:42 +0300 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2022-05-16 18:17:30 +0300 |
commit | 416bd7e7af602a14c41d87a94bec36a052d87181 (patch) | |
tree | f5cfa90405ae27794db39525f17cfa2595d4df48 /fs/btrfs/scrub.c | |
parent | 1194a82481d8f37892e0362b7e77d3627f51d017 (diff) | |
download | linux-416bd7e7af602a14c41d87a94bec36a052d87181.tar.xz |
btrfs: scrub: introduce a helper to locate an extent item
The new helper, find_first_extent_item(), will locate an extent item
(either EXTENT_ITEM or METADATA_ITEM) which covers any byte of the
search range.
This helper will later be used to refactor scrub code.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/scrub.c')
-rw-r--r-- | fs/btrfs/scrub.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 530913dcc76f..456df1b1ab9e 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -2859,6 +2859,113 @@ static void scrub_parity_put(struct scrub_parity *sparity) scrub_parity_check_and_repair(sparity); } +/* + * Return 0 if the extent item range covers any byte of the range. + * Return <0 if the extent item is before @search_start. + * Return >0 if the extent item is after @start_start + @search_len. + */ +static int compare_extent_item_range(struct btrfs_path *path, + u64 search_start, u64 search_len) +{ + struct btrfs_fs_info *fs_info = path->nodes[0]->fs_info; + u64 len; + struct btrfs_key key; + + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); + ASSERT(key.type == BTRFS_EXTENT_ITEM_KEY || + key.type == BTRFS_METADATA_ITEM_KEY); + if (key.type == BTRFS_METADATA_ITEM_KEY) + len = fs_info->nodesize; + else + len = key.offset; + + if (key.objectid + len <= search_start) + return -1; + if (key.objectid >= search_start + search_len) + return 1; + return 0; +} + +/* + * Locate one extent item which covers any byte in range + * [@search_start, @search_start + @search_length) + * + * If the path is not initialized, we will initialize the search by doing + * a btrfs_search_slot(). + * If the path is already initialized, we will use the path as the initial + * slot, to avoid duplicated btrfs_search_slot() calls. + * + * NOTE: If an extent item starts before @search_start, we will still + * return the extent item. This is for data extent crossing stripe boundary. + * + * Return 0 if we found such extent item, and @path will point to the extent item. + * Return >0 if no such extent item can be found, and @path will be released. + * Return <0 if hit fatal error, and @path will be released. + */ +static int find_first_extent_item(struct btrfs_root *extent_root, + struct btrfs_path *path, + u64 search_start, u64 search_len) +{ + struct btrfs_fs_info *fs_info = extent_root->fs_info; + struct btrfs_key key; + int ret; + + /* Continue using the existing path */ + if (path->nodes[0]) + goto search_forward; + + if (btrfs_fs_incompat(fs_info, SKINNY_METADATA)) + key.type = BTRFS_METADATA_ITEM_KEY; + else + key.type = BTRFS_EXTENT_ITEM_KEY; + key.objectid = search_start; + key.offset = (u64)-1; + + ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0); + if (ret < 0) + return ret; + + ASSERT(ret > 0); + /* + * Here we intentionally pass 0 as @min_objectid, as there could be + * an extent item starting before @search_start. + */ + ret = btrfs_previous_extent_item(extent_root, path, 0); + if (ret < 0) + return ret; + /* + * No matter whether we have found an extent item, the next loop will + * properly do every check on the key. + */ +search_forward: + while (true) { + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); + if (key.objectid >= search_start + search_len) + break; + if (key.type != BTRFS_METADATA_ITEM_KEY && + key.type != BTRFS_EXTENT_ITEM_KEY) + goto next; + + ret = compare_extent_item_range(path, search_start, search_len); + if (ret == 0) + return ret; + if (ret > 0) + break; +next: + path->slots[0]++; + if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { + ret = btrfs_next_leaf(extent_root, path); + if (ret) { + /* Either no more item or fatal error */ + btrfs_release_path(path); + return ret; + } + } + } + btrfs_release_path(path); + return 1; +} + static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx, struct map_lookup *map, struct btrfs_device *sdev, |