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Diffstat (limited to 'fs/btrfs/super.c')
-rw-r--r--fs/btrfs/super.c72
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;