diff options
| -rw-r--r-- | fs/btrfs/super.c | 72 |
1 files changed, 47 insertions, 25 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 54bd91ece35b..dc337d14ef5c 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1644,8 +1644,20 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes) int i = 0, nr_devices; int ret; + /* + * We aren't under the device list lock, so this is racey-ish, but good + * enough for our purposes. + */ nr_devices = fs_info->fs_devices->open_devices; - BUG_ON(!nr_devices); + if (!nr_devices) { + smp_mb(); + nr_devices = fs_info->fs_devices->open_devices; + ASSERT(nr_devices); + if (!nr_devices) { + *free_bytes = 0; + return 0; + } + } devices_info = kmalloc_array(nr_devices, sizeof(*devices_info), GFP_NOFS); @@ -1670,11 +1682,17 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes) else min_stripe_size = BTRFS_STRIPE_LEN; - list_for_each_entry(device, &fs_devices->devices, dev_list) { + if (fs_info->alloc_start) + mutex_lock(&fs_devices->device_list_mutex); + rcu_read_lock(); + list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) { if (!device->in_fs_metadata || !device->bdev || device->is_tgtdev_for_dev_replace) continue; + if (i >= nr_devices) + break; + avail_space = device->total_bytes - device->bytes_used; /* align with stripe_len */ @@ -1689,24 +1707,32 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes) 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) + if (fs_info->alloc_start && + fs_info->alloc_start + BTRFS_STRIPE_LEN <= + device->total_bytes) { + rcu_read_unlock(); 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; - } + /* + * 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); + mutex_unlock(&fs_devices->device_list_mutex); + return ret; + } - /* calc the free space in [0, skip_space - 1] */ - skip_space -= used_space; + rcu_read_lock(); + + /* 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 @@ -1725,6 +1751,9 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes) i++; } + rcu_read_unlock(); + if (fs_info->alloc_start) + mutex_unlock(&fs_devices->device_list_mutex); nr_devices = i; @@ -1787,8 +1816,6 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) * holding chunk_muext to avoid allocating new chunks, holding * device_list_mutex to avoid the device being removed */ - mutex_lock(&fs_info->fs_devices->device_list_mutex); - mutex_lock(&fs_info->chunk_mutex); rcu_read_lock(); list_for_each_entry_rcu(found, head, list) { if (found->flags & BTRFS_BLOCK_GROUP_DATA) { @@ -1826,15 +1853,10 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 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); - mutex_unlock(&fs_info->fs_devices->device_list_mutex); + if (ret) return ret; - } buf->f_bavail += div_u64(total_free_data, factor); buf->f_bavail = buf->f_bavail >> bits; - mutex_unlock(&fs_info->chunk_mutex); - mutex_unlock(&fs_info->fs_devices->device_list_mutex); buf->f_type = BTRFS_SUPER_MAGIC; buf->f_bsize = dentry->d_sb->s_blocksize; |