btrfs: adjust statfs calculations according to raid profiles (ba7b6e62) · Commits · 戴 / test

fs/btrfs/super.c

+45 −6

Original line number	Diff line number	Diff line
		@@ -1672,6 +1672,21 @@ static int btrfs_calc_avail_data_space(struct btrfs_root root, u64 free_bytes)
		return 0;
		}

		/*
		* Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
		*
		* If there's a redundant raid level at DATA block groups, use the respective
		* multiplier to scale the sizes.
		*
		* Unused device space usage is based on simulating the chunk allocator
		* algorithm that respects the device sizes, order of allocations and the
		* 'alloc_start' value, this is a close approximation of the actual use but
		* there are other factors that may change the result (like a new metadata
		* chunk).
		*
		* FIXME: not accurate for mixed block groups, total and free/used are ok,
		* available appears slightly larger.
		*/
		static int btrfs_statfs(struct dentry dentry, struct kstatfs buf)
		{
		struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
		@@ -1682,6 +1697,8 @@ static int btrfs_statfs(struct dentry dentry, struct kstatfs buf)
		u64 total_free_data = 0;
		int bits = dentry->d_sb->s_blocksize_bits;
		__be32 fsid = (__be32 )fs_info->fsid;
		unsigned factor = 1;
		struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
		int ret;

		/* holding chunk_muext to avoid allocating new chunks */
		@@ -1689,30 +1706,52 @@ static int btrfs_statfs(struct dentry dentry, struct kstatfs buf)
		rcu_read_lock();
		list_for_each_entry_rcu(found, head, list) {
		if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
		int i;

		total_free_data += found->disk_total - found->disk_used;
		total_free_data -=
		btrfs_account_ro_block_groups_free_space(found);

		for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
		if (!list_empty(&found->block_groups[i])) {
		switch (i) {
		case BTRFS_RAID_DUP:
		case BTRFS_RAID_RAID1:
		case BTRFS_RAID_RAID10:
		factor = 2;
		}
		}
		}
		}

		total_used += found->disk_used;
		}

		rcu_read_unlock();

		buf->f_namelen = BTRFS_NAME_LEN;
		buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
		buf->f_bfree = buf->f_blocks - (total_used >> bits);
		buf->f_bsize = dentry->d_sb->s_blocksize;
		buf->f_type = BTRFS_SUPER_MAGIC;
		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);

		/* Account global block reserve as used, it's in logical size already */
		spin_lock(&block_rsv->lock);
		buf->f_bfree -= block_rsv->size >> bits;
		spin_unlock(&block_rsv->lock);

		buf->f_bavail = total_free_data;
		ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
		if (ret) {
		mutex_unlock(&fs_info->chunk_mutex);
		return ret;
		}
		buf->f_bavail += total_free_data;
		buf->f_bavail += div_u64(total_free_data, factor);
		buf->f_bavail = buf->f_bavail >> bits;
		mutex_unlock(&fs_info->chunk_mutex);

		buf->f_type = BTRFS_SUPER_MAGIC;
		buf->f_bsize = dentry->d_sb->s_blocksize;
		buf->f_namelen = BTRFS_NAME_LEN;

		/* We treat it as constant endianness (it doesn't matter _which_)
		because we want the fsid to come out the same whether mounted
		on a big-endian or little-endian host */

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