Btrfs: A number of nodatacow fixes (bbaf549e) · Commits · 戴 / test

fs/btrfs/extent-tree.c

+20 −0

Original line number	Diff line number	Diff line
		@@ -731,6 +731,7 @@ u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
		u64 found_owner;
		u64 root_objectid = root->root_key.objectid;
		u32 total_count = 0;
		u32 extent_refs;
		u32 cur_count;
		u32 nritems;
		int ret;
		@@ -767,6 +768,7 @@ again:
		}

		item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
		extent_refs = btrfs_extent_refs(l, item);
		while (1) {
		l = path->nodes[0];
		nritems = btrfs_header_nritems(l);
		@@ -800,10 +802,28 @@ again:
		total_count = 2;
		goto out;
		}
		/*
		* nasty. we don't count a reference held by
		* the running transaction. This allows nodatacow
		* to avoid cow most of the time
		*/
		if (found_owner >= BTRFS_FIRST_FREE_OBJECTID &&
		btrfs_ref_generation(l, ref_item) ==
		root->fs_info->generation) {
		extent_refs--;
		}
		}
		total_count = 1;
		path->slots[0]++;
		}
		/*
		* if there is more than one reference against a data extent,
		* we have to assume the other ref is another snapshot
		*/
		if (level == -1 && extent_refs > 1) {
		total_count = 2;
		goto out;
		}
		if (cur_count == 0) {
		total_count = 0;
		goto out;

+3 −5

Original line number	Diff line number	Diff line
		@@ -207,9 +207,8 @@ again:
		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
		found_type = btrfs_key_type(&found_key);
		if (found_key.objectid != inode->i_ino \|\|
		found_type != BTRFS_EXTENT_DATA_KEY) {
		found_type != BTRFS_EXTENT_DATA_KEY)
		goto not_found;
		}

		found_type = btrfs_file_extent_type(leaf, item);
		extent_start = found_key.offset;
		@@ -245,7 +244,6 @@ again:
		if (!block_group \|\| block_group->ro)
		goto not_found;


		start = extent_end;
		} else {
		goto not_found;
		@@ -260,8 +258,8 @@ loop:
		goto again;

		not_found:
		cow_file_range(inode, start, cow_end);
		start = cow_end + 1;
		cow_file_range(inode, start, end);
		start = end + 1;
		goto loop;
		}