On 2017年12月20日 12:57, Su Yue wrote: > Excluding or pining all metadata blocks is not time-efficient for large > storage filesystems. > Here is another way to mark all metadata block groups full and allocate > a new chunk for CoW. So new reservered extents never overwrite > extents. > > Introduce modify_block_groups_cache() to modify all blocks groups > cache state and set all extents in block groups unfree in free space > cache. > > Suggested-by: Qu Wenruo <[email protected]> > Signed-off-by: Su Yue <[email protected]> > --- > cmds-check.c | 83 > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 83 insertions(+) > > diff --git a/cmds-check.c b/cmds-check.c > index dd46569f3811..d98d4bda7357 100644 > --- a/cmds-check.c > +++ b/cmds-check.c > @@ -10828,6 +10828,89 @@ static void reset_cached_block_groups(struct > btrfs_fs_info *fs_info) > } > } > > +/* > + * Mark all extents unfree in the block group. And set @block_group->cached > + * according to @cache. > + */ > +static int modify_block_group_cache(struct btrfs_fs_info *fs_info, > + struct btrfs_block_group_cache *block_group, int cache) > +{ > + struct extent_io_tree *free_space_cache = &fs_info->free_space_cache; > + u64 start = block_group->key.objectid; > + u64 end = start + block_group->key.offset; > + > + if (cache && !block_group->cached) { > + block_group->cached = 1; > + clear_extent_dirty(free_space_cache, start, end - 1); > + } > + > + if (!cache && block_group->cached) { > + block_group->cached = 0; > + clear_extent_dirty(free_space_cache, start, end - 1); > + } > + return 0; > +} > + > +/* > + * Modify block groups which have @flags unfree in free space cache. > + * > + * @cache: if 0, clear block groups cache state; > + * not 0, mark blocks groups cached.
The naming of the function and the @cache parameter is quite confusing.
And so is the later usage of the function.
It's used by both marking all block groups full and revert the full mark
as cleanup.
I would call the function mark_block_groups_full() to do the full
marking thing, without the extra @cache parameter.
And another function to clear_block_groups_full() to make them into back
to normal status.
Thanks,
Qu
> + */
> +static int modify_block_groups_cache(struct btrfs_fs_info *fs_info, u64
> flags,
> + int cache)
> +{
> + struct btrfs_root *root = fs_info->extent_root;
> + struct btrfs_key key;
> + struct btrfs_path path;
> + struct btrfs_block_group_cache *bg_cache;
> + struct btrfs_block_group_item *bi;
> + struct btrfs_block_group_item bg_item;
> + struct extent_buffer *eb;
> + int slot;
> + int ret;
> +
> + key.objectid = 0;
> + key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
> + key.offset = 0;
> +
> + btrfs_init_path(&path);
> + ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
> + if (ret < 0) {
> + error("fail to search block groups due to %s", strerror(-ret));
> + goto out;
> + }
> +
> + while (1) {
> + eb = path.nodes[0];
> + slot = path.slots[0];
> + btrfs_item_key_to_cpu(eb, &key, slot);
> + bg_cache = btrfs_lookup_block_group(fs_info, key.objectid);
> + if (!bg_cache) {
> + ret = -ENOENT;
> + goto out;
> + }
> +
> + bi = btrfs_item_ptr(eb, slot, struct btrfs_block_group_item);
> + read_extent_buffer(eb, &bg_item, (unsigned long)bi,
> + sizeof(bg_item));
> + if (btrfs_block_group_flags(&bg_item) & flags)
> + modify_block_group_cache(fs_info, bg_cache, cache);
> +
> + ret = btrfs_next_item(root, &path);
> + if (ret > 0) {
> + ret = 0;
> + goto out;
> + }
> + if (ret < 0)
> + goto out;
> + }
> +
> +out:
> + btrfs_release_path(&path);
> + return ret;
> +}
> +
> static int check_extent_refs(struct btrfs_root *root,
> struct cache_tree *extent_cache)
> {
>
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