Commit 72804905 authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: kill the RCU protection for fs_info->space_info 



We have this thing wrapped in an RCU lock, but it's really not needed.
We create all the space_info's on mount, and we destroy them on unmount.
The list never changes and we're protected from messing with it by the
normal mount/umount path, so kill the RCU stuff around it.

Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 7269ddd2

fs/btrfs/block-group.c

+2 −14
Original line number Diff line number Diff line
@@ -2031,8 +2031,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) 
		btrfs_release_path(path);

	}



	rcu_read_lock();

	list_for_each_entry_rcu(space_info, &info->space_info, list) {

	list_for_each_entry(space_info, &info->space_info, list) {

		if (!(btrfs_get_alloc_profile(info, space_info->flags) &

		      (BTRFS_BLOCK_GROUP_RAID10 |

		       BTRFS_BLOCK_GROUP_RAID1_MASK |
@@ -2052,7 +2051,6 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) 
				list)

			inc_block_group_ro(cache, 1);

	}

	rcu_read_unlock();



	btrfs_init_global_block_rsv(info);

	ret = check_chunk_block_group_mappings(info);
@@ -3007,12 +3005,10 @@ static void force_metadata_allocation(struct btrfs_fs_info *info) 
	struct list_head *head = &info->space_info;

	struct btrfs_space_info *found;



	rcu_read_lock();

	list_for_each_entry_rcu(found, head, list) {

	list_for_each_entry(found, head, list) {

		if (found->flags & BTRFS_BLOCK_GROUP_METADATA)

			found->force_alloc = CHUNK_ALLOC_FORCE;

	}

	rcu_read_unlock();

}



static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
@@ -3343,14 +3339,6 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info) 
	}

	spin_unlock(&info->block_group_cache_lock);



	/*

	 * Now that all the block groups are freed, go through and free all the

	 * space_info structs.  This is only called during the final stages of

	 * unmount, and so we know nobody is using them.  We call

	 * synchronize_rcu() once before we start, just to be on the safe side.

	 */

	synchronize_rcu();



	btrfs_release_global_block_rsv(info);



	while (!list_empty(&info->space_info)) {

fs/btrfs/ioctl.c

+2 −8
Original line number Diff line number Diff line
@@ -3475,15 +3475,12 @@ static long btrfs_ioctl_space_info(struct btrfs_fs_info *fs_info, 
		struct btrfs_space_info *tmp;



		info = NULL;

		rcu_read_lock();

		list_for_each_entry_rcu(tmp, &fs_info->space_info,

					list) {

		list_for_each_entry(tmp, &fs_info->space_info, list) {

			if (tmp->flags == types[i]) {

				info = tmp;

				break;

			}

		}

		rcu_read_unlock();



		if (!info)

			continue;
@@ -3531,15 +3528,12 @@ static long btrfs_ioctl_space_info(struct btrfs_fs_info *fs_info, 
			break;



		info = NULL;

		rcu_read_lock();

		list_for_each_entry_rcu(tmp, &fs_info->space_info,

					list) {

		list_for_each_entry(tmp, &fs_info->space_info, list) {

			if (tmp->flags == types[i]) {

				info = tmp;

				break;

			}

		}

		rcu_read_unlock();



		if (!info)

			continue;

fs/btrfs/space-info.c

+4 −10
Original line number Diff line number Diff line
@@ -175,10 +175,8 @@ void btrfs_clear_space_info_full(struct btrfs_fs_info *info) 
	struct list_head *head = &info->space_info;

	struct btrfs_space_info *found;



	rcu_read_lock();

	list_for_each_entry_rcu(found, head, list)

	list_for_each_entry(found, head, list)

		found->full = 0;

	rcu_read_unlock();

}



static int create_space_info(struct btrfs_fs_info *info, u64 flags)
@@ -213,7 +211,7 @@ static int create_space_info(struct btrfs_fs_info *info, u64 flags) 
	if (ret)

		return ret;



	list_add_rcu(&space_info->list, &info->space_info);

	list_add(&space_info->list, &info->space_info);

	if (flags & BTRFS_BLOCK_GROUP_DATA)

		info->data_sinfo = space_info;
@@ -290,14 +288,10 @@ struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info, 


	flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;



	rcu_read_lock();

	list_for_each_entry_rcu(found, head, list) {

		if (found->flags & flags) {

			rcu_read_unlock();

	list_for_each_entry(found, head, list) {

		if (found->flags & flags)

			return found;

	}

	}

	rcu_read_unlock();

	return NULL;

}

fs/btrfs/super.c

+1 −4
Original line number Diff line number Diff line
@@ -2164,8 +2164,7 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 
	u64 thresh = 0;

	int mixed = 0;



	rcu_read_lock();

	list_for_each_entry_rcu(found, &fs_info->space_info, list) {

	list_for_each_entry(found, &fs_info->space_info, list) {

		if (found->flags & BTRFS_BLOCK_GROUP_DATA) {

			int i;
@@ -2194,8 +2193,6 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 
		total_used += found->disk_used;

	}



	rcu_read_unlock();



	buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);

	buf->f_blocks >>= bits;

	buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);

CRA Git | Maintained and supported by SUSTech CRA and CCSE