diff options
Diffstat (limited to 'fs/btrfs/super.c')
| -rw-r--r-- | fs/btrfs/super.c | 146 |
1 files changed, 140 insertions, 6 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index caa5bcc..2963376 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -777,6 +777,127 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) return 0; } +/* + * The helper to calc the free space on the devices that can be used to store + * file data. + */ +static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_device_info *devices_info; + struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; + struct btrfs_device *device; + u64 skip_space; + u64 type; + u64 avail_space; + u64 used_space; + u64 min_stripe_size; + int min_stripes = 1; + int i = 0, nr_devices; + int ret; + + nr_devices = fs_info->fs_devices->rw_devices; + BUG_ON(!nr_devices); + + devices_info = kmalloc(sizeof(*devices_info) * nr_devices, + GFP_NOFS); + if (!devices_info) + return -ENOMEM; + + /* calc min stripe number for data space alloction */ + type = btrfs_get_alloc_profile(root, 1); + if (type & BTRFS_BLOCK_GROUP_RAID0) + min_stripes = 2; + else if (type & BTRFS_BLOCK_GROUP_RAID1) + min_stripes = 2; + else if (type & BTRFS_BLOCK_GROUP_RAID10) + min_stripes = 4; + + if (type & BTRFS_BLOCK_GROUP_DUP) + min_stripe_size = 2 * BTRFS_STRIPE_LEN; + else + min_stripe_size = BTRFS_STRIPE_LEN; + + list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) { + if (!device->in_fs_metadata) + continue; + + avail_space = device->total_bytes - device->bytes_used; + + /* align with stripe_len */ + do_div(avail_space, BTRFS_STRIPE_LEN); + avail_space *= BTRFS_STRIPE_LEN; + + /* + * In order to avoid overwritting the superblock on the drive, + * btrfs starts at an offset of at least 1MB when doing chunk + * allocation. + */ + skip_space = 1024 * 1024; + + /* user can set the offset in fs_info->alloc_start. */ + if (fs_info->alloc_start + BTRFS_STRIPE_LEN <= + device->total_bytes) + skip_space = max(fs_info->alloc_start, skip_space); + + /* + * btrfs can not use the free space in [0, skip_space - 1], + * we must subtract it from the total. In order to implement + * it, we account the used space in this range first. + */ + ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1, + &used_space); + if (ret) { + kfree(devices_info); + return ret; + } + + /* calc the free space in [0, skip_space - 1] */ + skip_space -= used_space; + + /* + * we can use the free space in [0, skip_space - 1], subtract + * it from the total. + */ + if (avail_space && avail_space >= skip_space) + avail_space -= skip_space; + else + avail_space = 0; + + if (avail_space < min_stripe_size) + continue; + + devices_info[i].dev = device; + devices_info[i].max_avail = avail_space; + + i++; + } + + nr_devices = i; + + btrfs_descending_sort_devices(devices_info, nr_devices); + + i = nr_devices - 1; + avail_space = 0; + while (nr_devices >= min_stripes) { + if (devices_info[i].max_avail >= min_stripe_size) { + int j; + u64 alloc_size; + + avail_space += devices_info[i].max_avail * min_stripes; + alloc_size = devices_info[i].max_avail; + for (j = i + 1 - min_stripes; j <= i; j++) + devices_info[j].max_avail -= alloc_size; + } + i--; + nr_devices--; + } + + kfree(devices_info); + *free_bytes = avail_space; + return 0; +} + static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) { struct btrfs_root *root = btrfs_sb(dentry->d_sb); @@ -784,16 +905,21 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) struct list_head *head = &root->fs_info->space_info; struct btrfs_space_info *found; u64 total_used = 0; - u64 total_used_data = 0; + u64 total_free_data = 0; int bits = dentry->d_sb->s_blocksize_bits; __be32 *fsid = (__be32 *)root->fs_info->fsid; + int ret; + /* holding chunk_muext to avoid allocating new chunks */ + mutex_lock(&root->fs_info->chunk_mutex); rcu_read_lock(); list_for_each_entry_rcu(found, head, list) { - if (found->flags & BTRFS_BLOCK_GROUP_DATA) - total_used_data += found->disk_used; - else - total_used_data += found->disk_total; + if (found->flags & BTRFS_BLOCK_GROUP_DATA) { + total_free_data += found->disk_total - found->disk_used; + total_free_data -= + btrfs_account_ro_block_groups_free_space(found); + } + total_used += found->disk_used; } rcu_read_unlock(); @@ -801,9 +927,17 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 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_bavail = buf->f_blocks - (total_used_data >> bits); buf->f_bsize = dentry->d_sb->s_blocksize; buf->f_type = BTRFS_SUPER_MAGIC; + buf->f_bavail = total_free_data; + ret = btrfs_calc_avail_data_space(root, &total_free_data); + if (ret) { + mutex_unlock(&root->fs_info->chunk_mutex); + return ret; + } + buf->f_bavail += total_free_data; + buf->f_bavail = buf->f_bavail >> bits; + mutex_unlock(&root->fs_info->chunk_mutex); /* We treat it as constant endianness (it doesn't matter _which_) because we want the fsid to come out the same whether mounted |
