Only minor nits
On Fri, May 19, 2017 at 10:21:06AM +0300, Nikolay Borisov wrote:
> Currently the struct space_info creation code is intermixed in the
> udpate_space_info function. There are well-defined points at which the we
^^^^^^^^^^^^^^^^^
> actually want to create brand-new space_info structs (e.g. during mount of
> the filesystem as well as sometimes when adding/initialising new chunks). In
> such cases udpate_space_info is called with 0 as the bytes parameter. All of
^^^^^^^^^^^^^^^^^
> this makes for spaghetti code.
>
> Fix it by factoring out the creation code in a separate create_space_info
> structure. This also allows to simplify the internals. Also remove BUG_ON from
> do_alloc_chunk since the callers handle errors. Furthermore it will
> make the update_space_info function not fail, allowing us to remove error
> handling in callers. This will come in a follow up patch.
>
> Reviewed-by: Jeff Mahoney <jeffm@xxxxxxxx>
> Reviewed-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
Missing signed-off-by
> ---
> fs/btrfs/extent-tree.c | 129 ++++++++++++++++++++++++-------------------------
> 1 file changed, 64 insertions(+), 65 deletions(-)
>
>
> Worked on feedback from Liu Bo and discovered I didn't have vim's linuxtsy
> plugin installed, hence the b0rked formatting in some of my patches.
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index be5477676cc8..55b6836f5a20 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -3914,15 +3914,58 @@ static const char *alloc_name(u64 flags)
> };
> }
>
> +static int create_space_info(struct btrfs_fs_info *info, u64 flags,
> + struct btrfs_space_info **new) {
function openning { on a new line
> +
> + struct btrfs_space_info *space_info;
> + int i;
> + int ret;
> +
> + space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
> + if (!space_info)
> + return -ENOMEM;
> +
> + ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
> + GFP_KERNEL);
> + if (ret) {
> + kfree(space_info);
> + return ret;
> + }
> +
> + for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
> + INIT_LIST_HEAD(&space_info->block_groups[i]);
> + init_rwsem(&space_info->groups_sem);
> + spin_lock_init(&space_info->lock);
> + space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
> + space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
> + init_waitqueue_head(&space_info->wait);
> + INIT_LIST_HEAD(&space_info->ro_bgs);
> + INIT_LIST_HEAD(&space_info->tickets);
> + INIT_LIST_HEAD(&space_info->priority_tickets);
> +
> + ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
> + info->space_info_kobj, "%s",
> + alloc_name(space_info->flags));
> + if (ret) {
> + kfree(space_info);
> + return ret;
> + }
> +
> + *new = space_info;
> + list_add_rcu(&space_info->list, &info->space_info);
> + if (flags & BTRFS_BLOCK_GROUP_DATA)
> + info->data_sinfo = space_info;
> +
> + return ret;
> +}
> +
> static int update_space_info(struct btrfs_fs_info *info, u64 flags,
> u64 total_bytes, u64 bytes_used,
> u64 bytes_readonly,
> struct btrfs_space_info **space_info)
> {
> struct btrfs_space_info *found;
> - int i;
> int factor;
> - int ret;
>
> if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
> BTRFS_BLOCK_GROUP_RAID10))
> @@ -3946,53 +3989,6 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
> *space_info = found;
> return 0;
> }
> - found = kzalloc(sizeof(*found), GFP_NOFS);
> - if (!found)
> - return -ENOMEM;
> -
> - ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
> - if (ret) {
> - kfree(found);
> - return ret;
> - }
> -
> - for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
> - INIT_LIST_HEAD(&found->block_groups[i]);
> - init_rwsem(&found->groups_sem);
> - spin_lock_init(&found->lock);
> - found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
> - found->total_bytes = total_bytes;
> - found->disk_total = total_bytes * factor;
> - found->bytes_used = bytes_used;
> - found->disk_used = bytes_used * factor;
> - found->bytes_pinned = 0;
> - found->bytes_reserved = 0;
> - found->bytes_readonly = bytes_readonly;
> - found->bytes_may_use = 0;
> - found->full = 0;
> - found->max_extent_size = 0;
> - found->force_alloc = CHUNK_ALLOC_NO_FORCE;
> - found->chunk_alloc = 0;
> - found->flush = 0;
> - init_waitqueue_head(&found->wait);
> - INIT_LIST_HEAD(&found->ro_bgs);
> - INIT_LIST_HEAD(&found->tickets);
> - INIT_LIST_HEAD(&found->priority_tickets);
> -
> - ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
> - info->space_info_kobj, "%s",
> - alloc_name(found->flags));
> - if (ret) {
> - kfree(found);
> - return ret;
> - }
> -
> - *space_info = found;
> - list_add_rcu(&found->list, &info->space_info);
> - if (flags & BTRFS_BLOCK_GROUP_DATA)
> - info->data_sinfo = found;
> -
> - return ret;
> }
>
> static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
> @@ -4495,10 +4491,10 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
>
> space_info = __find_space_info(fs_info, flags);
> if (!space_info) {
> - ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
> - BUG_ON(ret); /* -ENOMEM */
> + ret = create_space_info(fs_info, flags, &space_info);
> + if (ret)
> + return -ENOMEM;
create_space_info can possibly return other codes than just ENOMEM,
'return ret' is fine here.
Otherwise looks good.
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