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authorQu Wenruo <wqu@suse.com>2020-02-13 10:04:04 +0300
committerDavid Sterba <dsterba@suse.com>2020-05-25 12:25:16 +0300
commitc39c2ddc67024979915c4df4e30da96a3e7619b0 (patch)
tree7703dc2910b9c0276a5851468b3dceacec2eb33c
parenta37f232b7b65789cadc9834d389f6390de11b583 (diff)
downloadlinux-c39c2ddc67024979915c4df4e30da96a3e7619b0.tar.xz
btrfs: backref: implement btrfs_backref_iter_next()
This function will go to the next inline/keyed backref for btrfs_backref_iter infrastructure. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/backref.c60
-rw-r--r--fs/btrfs/backref.h34
2 files changed, 94 insertions, 0 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index a1bac1b87d17..27f9a5923796 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -2405,3 +2405,63 @@ release:
btrfs_backref_iter_release(iter);
return ret;
}
+
+/*
+ * Go to the next backref item of current bytenr, can be either inlined or
+ * keyed.
+ *
+ * Caller needs to check whether it's inline ref or not by iter->cur_key.
+ *
+ * Return 0 if we get next backref without problem.
+ * Return >0 if there is no extra backref for this bytenr.
+ * Return <0 if there is something wrong happened.
+ */
+int btrfs_backref_iter_next(struct btrfs_backref_iter *iter)
+{
+ struct extent_buffer *eb = btrfs_backref_get_eb(iter);
+ struct btrfs_path *path = iter->path;
+ struct btrfs_extent_inline_ref *iref;
+ int ret;
+ u32 size;
+
+ if (btrfs_backref_iter_is_inline_ref(iter)) {
+ /* We're still inside the inline refs */
+ ASSERT(iter->cur_ptr < iter->end_ptr);
+
+ if (btrfs_backref_has_tree_block_info(iter)) {
+ /* First tree block info */
+ size = sizeof(struct btrfs_tree_block_info);
+ } else {
+ /* Use inline ref type to determine the size */
+ int type;
+
+ iref = (struct btrfs_extent_inline_ref *)
+ ((unsigned long)iter->cur_ptr);
+ type = btrfs_extent_inline_ref_type(eb, iref);
+
+ size = btrfs_extent_inline_ref_size(type);
+ }
+ iter->cur_ptr += size;
+ if (iter->cur_ptr < iter->end_ptr)
+ return 0;
+
+ /* All inline items iterated, fall through */
+ }
+
+ /* We're at keyed items, there is no inline item, go to the next one */
+ ret = btrfs_next_item(iter->fs_info->extent_root, iter->path);
+ if (ret)
+ return ret;
+
+ btrfs_item_key_to_cpu(path->nodes[0], &iter->cur_key, path->slots[0]);
+ if (iter->cur_key.objectid != iter->bytenr ||
+ (iter->cur_key.type != BTRFS_TREE_BLOCK_REF_KEY &&
+ iter->cur_key.type != BTRFS_SHARED_BLOCK_REF_KEY))
+ return 1;
+ iter->item_ptr = (u32)btrfs_item_ptr_offset(path->nodes[0],
+ path->slots[0]);
+ iter->cur_ptr = iter->item_ptr;
+ iter->end_ptr = iter->item_ptr + (u32)btrfs_item_size_nr(path->nodes[0],
+ path->slots[0]);
+ return 0;
+}
diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index 4ae37fad819a..46faf9b93576 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -104,8 +104,42 @@ static inline void btrfs_backref_iter_free(struct btrfs_backref_iter *iter)
kfree(iter);
}
+static inline struct extent_buffer *btrfs_backref_get_eb(
+ struct btrfs_backref_iter *iter)
+{
+ if (!iter)
+ return NULL;
+ return iter->path->nodes[0];
+}
+
+/*
+ * For metadata with EXTENT_ITEM key (non-skinny) case, the first inline data
+ * is btrfs_tree_block_info, without a btrfs_extent_inline_ref header.
+ *
+ * This helper determines if that's the case.
+ */
+static inline bool btrfs_backref_has_tree_block_info(
+ struct btrfs_backref_iter *iter)
+{
+ if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY &&
+ iter->cur_ptr - iter->item_ptr == sizeof(struct btrfs_extent_item))
+ return true;
+ return false;
+}
+
int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr);
+int btrfs_backref_iter_next(struct btrfs_backref_iter *iter);
+
+static inline bool btrfs_backref_iter_is_inline_ref(
+ struct btrfs_backref_iter *iter)
+{
+ if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY ||
+ iter->cur_key.type == BTRFS_METADATA_ITEM_KEY)
+ return true;
+ return false;
+}
+
static inline void btrfs_backref_iter_release(struct btrfs_backref_iter *iter)
{
iter->bytenr = 0;