On 2017年12月20日 12:57, Su Yue wrote:
> Define a global enum extents_operation to record extents are pinned,
> excluded or new chunk is allocated for extents.
> Although global variable is not so graceful, it simplifies codes much.
>
> New function try_avoid_extents_overwrite() will try to mark block
> groups full and allocate a new chunk. If it failed because of no space
> or wrong used bytes(fsck-tests/004), then try to exclude metadata
> blocks.
>
> Signed-off-by: Su Yue <suy.fnst@xxxxxxxxxxxxxx>
> ---
> cmds-check.c | 101 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 101 insertions(+)
>
> diff --git a/cmds-check.c b/cmds-check.c
> index 311c8a9f45e8..9042bab93785 100644
> --- a/cmds-check.c
> +++ b/cmds-check.c
> @@ -84,6 +84,15 @@ enum btrfs_check_mode {
>
> static enum btrfs_check_mode check_mode = CHECK_MODE_DEFAULT;
>
> +enum lowmem_extents_operation {
> + EXTENTS_PIN,
> + EXTENTS_EXCLUDE,
> + EXTENTS_MARK_BG_FULL,
> + EXTENTS_NONE
> +};
> +
> +static enum lowmem_extents_operation extents_operation = EXTENTS_NONE;
> +
> struct extent_backref {
> struct rb_node node;
> unsigned int is_data:1;
> @@ -13517,6 +13526,98 @@ 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_PIN:
> + ret = btrfs_finish_extent_commit(NULL, fs_info->extent_root,
> + &fs_info->pinned_extents);
> + break;
Any particular reason to support pining down extents?
As I already mentioned in the bug fix patch, pin will cause extent to be
considered as free after transaction commitment.
Or it's only designed to support extent-tree rebuild?
At least I didn't see any where using EXTENT_PIN in the patchset.
Thanks,
Qu
> + 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)
> + return 0;
> +
> + switch (op) {
> + case EXTENTS_PIN:
> + ret = pin_metadata_blocks(fs_info);
> + break;
> + case EXTENTS_EXCLUDE:
> + ret = exclude_metadata_blocks(fs_info);
> + break;
> + case EXTENTS_MARK_BG_FULL:
> + ret = force_cow_in_new_chunk(fs_info);
> + break;
> + case EXTENTS_NONE:
> + ret = 0;
> + 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)
> + 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.
> */
>
Attachment:
signature.asc
Description: OpenPGP digital signature
