On 2017年12月20日 12:57, Su Yue wrote:
> Since extents can be avoid overwrite by excluding or new chunk
> allocation. It's unnessesary to do all repairs in one transaction.
>
> This patch removes parameter @trans of repair_extent_data_item().
> repair_extent_data_item() calls try_avoid_extents_overwrite()
> and starts a transaction by itself.
>
> Note: This patch and next patches cause error in lowmem repair like:
> "Error: Commit_root already set when starting transaction".
> This error will disappear after removing @trans finished.
>
> Signed-off-by: Su Yue <suy.fnst@xxxxxxxxxxxxxx>
> ---
> cmds-check.c | 24 +++++++++++++++++++-----
> 1 file changed, 19 insertions(+), 5 deletions(-)
>
> diff --git a/cmds-check.c b/cmds-check.c
> index bc405d0f3fc0..20bf3d230946 100644
> --- a/cmds-check.c
> +++ b/cmds-check.c
> @@ -12064,18 +12064,19 @@ out:
> return err;
> }
>
> +static int try_avoid_extents_overwrite(struct btrfs_fs_info *fs_info);
> /*
> * If @err contains BACKREF_MISSING then add extent of the
> * file_extent_data_item.
> *
> * Returns error bits after reapir.
> */
> -static int repair_extent_data_item(struct btrfs_trans_handle *trans,
> - struct btrfs_root *root,
> +static int repair_extent_data_item(struct btrfs_root *root,
> struct btrfs_path *pathp,
> struct node_refs *nrefs,
> int err)
> {
> + struct btrfs_trans_handle *trans = NULL;
> struct btrfs_file_extent_item *fi;
> struct btrfs_key fi_key;
> struct btrfs_key key;
> @@ -12092,6 +12093,7 @@ static int repair_extent_data_item(struct btrfs_trans_handle *trans,
> u64 file_offset;
> int generation;
> int slot;
> + int need_insert = 0;
> int ret = 0;
>
> eb = pathp->nodes[0];
> @@ -12130,9 +12132,20 @@ static int repair_extent_data_item(struct btrfs_trans_handle *trans,
> ret = -EIO;
> goto out;
> }
> + need_insert = ret;
>
> + ret = try_avoid_extents_overwrite(root->fs_info);
Even it's much cheaper to pin extent tree using chunk unit, I don't
think it's a good idea to do it every time you are going to fix some
extent tree problem.
Why not just do it at the beginning of extent tree check?
Thanks,
Qu
> + if (ret)
> + goto out;
> + trans = btrfs_start_transaction(root, 1);
> + if (IS_ERR(trans)) {
> + ret = PTR_ERR(trans);
> + trans = NULL;
> + error("fail to start transaction %s", strerror(-ret));
> + goto out;
> + }
> /* insert an extent item */
> - if (ret > 0) {
> + if (need_insert) {
> key.objectid = disk_bytenr;
> key.type = BTRFS_EXTENT_ITEM_KEY;
> key.offset = num_bytes;
> @@ -12172,6 +12185,8 @@ static int repair_extent_data_item(struct btrfs_trans_handle *trans,
>
> err &= ~BACKREF_MISSING;
> out:
> + if (trans)
> + btrfs_commit_transaction(trans, root);
> btrfs_release_path(&path);
> if (ret)
> error("can't repair root %llu extent data item[%llu %llu]",
> @@ -13445,8 +13460,7 @@ again:
> case BTRFS_EXTENT_DATA_KEY:
> ret = check_extent_data_item(root, path, nrefs, account_bytes);
> if (repair && ret)
> - ret = repair_extent_data_item(trans, root, path, nrefs,
> - ret);
> + ret = repair_extent_data_item(root, path, nrefs, ret);
> err |= ret;
> break;
> case BTRFS_BLOCK_GROUP_ITEM_KEY:
>
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