@@ -84,6 +84,15 @@ enum btrfs_check_mode {
static enum btrfs_check_mode check_mode = CHECK_MODE_DEFAULT;
+enum lowmem_extents_operation {
+ EXTENTS_NONE,
+ EXTENTS_EXCLUDE,
+ EXTENTS_MARK_BG_FULL,
+};
+
+static enum lowmem_extents_operation extents_operation = EXTENTS_NONE;
+static u64 last_allocated_chunk;
+
struct extent_backref {
struct rb_node node;
unsigned int is_data:1;
@@ -11074,6 +11083,23 @@ out:
return ret;
}
+/*
+ * Returns <0 for error.
+ * Returns 0 for success.
+ */
+static int try_to_force_cow_in_new_chunk(struct btrfs_fs_info *fs_info)
+{
+ int ret;
+
+ if (last_allocated_chunk) {
+ ret = is_chunk_almost_full(fs_info, last_allocated_chunk);
+ if (ret <= 0)
+ return ret;
+ }
+ ret = force_cow_in_new_chunk(fs_info, &last_allocated_chunk);
+ return ret;
+}
+
static int check_extent_refs(struct btrfs_root *root,
struct cache_tree *extent_cache)
{
@@ -13600,6 +13626,92 @@ out:
return err;
}
+static void cleanup_excluded_extents(struct btrfs_fs_info *fs_info);
+static int end_avoid_extents_overwrite(struct btrfs_fs_info *fs_info)
+{
+ int ret;
+
+ switch (extents_operation) {
+ case EXTENTS_EXCLUDE:
+ cleanup_excluded_extents(fs_info);
+ ret = 0;
+ break;
+ case EXTENTS_MARK_BG_FULL:
+ ret = modify_block_groups_cache(fs_info,
+ BTRFS_BLOCK_GROUP_METADATA, 0);
+ break;
+ case EXTENTS_NONE:
+ ret = 0;
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ if (!ret)
+ extents_operation = EXTENTS_NONE;
+ return ret;
+}
+
+static int pin_metadata_blocks(struct btrfs_fs_info *fs_info);
+static int exclude_metadata_blocks(struct btrfs_fs_info *fs_info);
+/*
+ * NOTE: Do not call this function during transaction.
+ */
+static int avoid_extents_overwrite(struct btrfs_fs_info *fs_info,
+ enum lowmem_extents_operation op)
+{
+ int ret;
+
+ if (op == extents_operation && EXTENTS_MARK_BG_FULL != op)
+ return 0;
+
+ switch (op) {
+ case EXTENTS_EXCLUDE:
+ ret = exclude_metadata_blocks(fs_info);
+ break;
+ case EXTENTS_MARK_BG_FULL:
+ ret = try_to_force_cow_in_new_chunk(fs_info);
+ break;
+ case EXTENTS_NONE:
+ ret = end_avoid_extents_overwrite(fs_info);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* extents_operation should be assigned anyway for latter clean up. */
+ extents_operation = op;
+
+ if (ret)
+ end_avoid_extents_overwrite(fs_info);
+ return ret;
+}
+
+static int try_avoid_extents_overwrite(struct btrfs_fs_info *fs_info)
+{
+ int ret;
+ int mixed = btrfs_fs_incompat(fs_info, MIXED_GROUPS);
+
+ if (extents_operation != EXTENTS_NONE &&
+ extents_operation != EXTENTS_MARK_BG_FULL)
+ return 0;
+ ret = avoid_extents_overwrite(fs_info, EXTENTS_MARK_BG_FULL);
+
+ /*
+ * If there is no space left to allocate, try to exclude all metadata
+ * blocks. Mix filesystem is unsupported.
+ */
+ if (ret && ret == -ENOSPC && !mixed) {
+ printf(
+ "Try to exclude all metadata blcoks and extents, it may be slow\n");
+ ret = avoid_extents_overwrite(fs_info, EXTENTS_EXCLUDE);
+ }
+
+ if (ret)
+ error("failed to avoid extents overwrite %s", strerror(-ret));
+ return ret;
+}
+
/*
* Low memory usage version check_chunks_and_extents.
*/
Define a global enum extents_operation to record extents are excluded or new chunk is allocated for extents. Another global u64 last_allocated_chunk records the last chunk start allocated by lowmem repair. Although global variable is not so graceful, it simplifies codes much. New function try_to_force_cow_in_new_chunk() will try to mark block groups full, allocate a new chunk and records the start. If the last allocated chunk is almost full, a new chunk will be allocated. try_avoid_extents_overwrite() prefer to allocates new chunk first. If it failed because of no space or wrong used bytes(fsck-tests/004), then it try to exclude metadata blocks but costs lots of time in large filesystem. Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com> --- cmds-check.c | 112 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 112 insertions(+)