Btrfs: add basic restriper infrastructure
Add basic restriper infrastructure: extended balancing ioctl and all
related ioctl data structures, add data structure for tracking
restriper's state to fs_info, etc. The semantics of the old balancing
ioctl are fully preserved.
Explicitly disallow any volume operations when balance is in progress.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d5fdee5..9fc06e6b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1282,7 +1282,6 @@
bool clear_super = false;
mutex_lock(&uuid_mutex);
- mutex_lock(&root->fs_info->volume_mutex);
all_avail = root->fs_info->avail_data_alloc_bits |
root->fs_info->avail_system_alloc_bits |
@@ -1452,7 +1451,6 @@
if (bdev)
blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
out:
- mutex_unlock(&root->fs_info->volume_mutex);
mutex_unlock(&uuid_mutex);
return ret;
error_undo:
@@ -1629,7 +1627,6 @@
}
filemap_write_and_wait(bdev->bd_inode->i_mapping);
- mutex_lock(&root->fs_info->volume_mutex);
devices = &root->fs_info->fs_devices->devices;
/*
@@ -1757,8 +1754,7 @@
ret = btrfs_relocate_sys_chunks(root);
BUG_ON(ret);
}
-out:
- mutex_unlock(&root->fs_info->volume_mutex);
+
return ret;
error:
blkdev_put(bdev, FMODE_EXCL);
@@ -1766,7 +1762,7 @@
mutex_unlock(&uuid_mutex);
up_write(&sb->s_umount);
}
- goto out;
+ return ret;
}
static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
@@ -2077,6 +2073,35 @@
return ret;
}
+/*
+ * Should be called with both balance and volume mutexes held to
+ * serialize other volume operations (add_dev/rm_dev/resize) with
+ * restriper. Same goes for unset_balance_control.
+ */
+static void set_balance_control(struct btrfs_balance_control *bctl)
+{
+ struct btrfs_fs_info *fs_info = bctl->fs_info;
+
+ BUG_ON(fs_info->balance_ctl);
+
+ spin_lock(&fs_info->balance_lock);
+ fs_info->balance_ctl = bctl;
+ spin_unlock(&fs_info->balance_lock);
+}
+
+static void unset_balance_control(struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_balance_control *bctl = fs_info->balance_ctl;
+
+ BUG_ON(!fs_info->balance_ctl);
+
+ spin_lock(&fs_info->balance_lock);
+ fs_info->balance_ctl = NULL;
+ spin_unlock(&fs_info->balance_lock);
+
+ kfree(bctl);
+}
+
static u64 div_factor(u64 num, int factor)
{
if (factor == 10)
@@ -2086,29 +2111,23 @@
return num;
}
-int btrfs_balance(struct btrfs_root *dev_root)
+static int __btrfs_balance(struct btrfs_fs_info *fs_info)
{
- int ret;
- struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
+ struct btrfs_root *chunk_root = fs_info->chunk_root;
+ struct btrfs_root *dev_root = fs_info->dev_root;
+ struct list_head *devices;
struct btrfs_device *device;
u64 old_size;
u64 size_to_free;
struct btrfs_path *path;
struct btrfs_key key;
- struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
- struct btrfs_trans_handle *trans;
struct btrfs_key found_key;
-
- if (dev_root->fs_info->sb->s_flags & MS_RDONLY)
- return -EROFS;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- mutex_lock(&dev_root->fs_info->volume_mutex);
- dev_root = dev_root->fs_info->dev_root;
+ struct btrfs_trans_handle *trans;
+ int ret;
+ int enospc_errors = 0;
/* step one make some room on all the devices */
+ devices = &fs_info->fs_devices->devices;
list_for_each_entry(device, devices, dev_list) {
old_size = device->total_bytes;
size_to_free = div_factor(old_size, 1);
@@ -2151,12 +2170,14 @@
* failed
*/
if (ret == 0)
- break;
+ BUG(); /* FIXME break ? */
ret = btrfs_previous_item(chunk_root, path, 0,
BTRFS_CHUNK_ITEM_KEY);
- if (ret)
+ if (ret) {
+ ret = 0;
break;
+ }
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
@@ -2174,12 +2195,63 @@
found_key.offset);
if (ret && ret != -ENOSPC)
goto error;
+ if (ret == -ENOSPC)
+ enospc_errors++;
key.offset = found_key.offset - 1;
}
- ret = 0;
+
error:
btrfs_free_path(path);
- mutex_unlock(&dev_root->fs_info->volume_mutex);
+ if (enospc_errors) {
+ printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
+ enospc_errors);
+ if (!ret)
+ ret = -ENOSPC;
+ }
+
+ return ret;
+}
+
+static void __cancel_balance(struct btrfs_fs_info *fs_info)
+{
+ unset_balance_control(fs_info);
+}
+
+void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
+ struct btrfs_ioctl_balance_args *bargs);
+
+/*
+ * Should be called with both balance and volume mutexes held
+ */
+int btrfs_balance(struct btrfs_balance_control *bctl,
+ struct btrfs_ioctl_balance_args *bargs)
+{
+ struct btrfs_fs_info *fs_info = bctl->fs_info;
+ int ret;
+
+ if (btrfs_fs_closing(fs_info)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ set_balance_control(bctl);
+
+ mutex_unlock(&fs_info->balance_mutex);
+
+ ret = __btrfs_balance(fs_info);
+
+ mutex_lock(&fs_info->balance_mutex);
+
+ if (bargs) {
+ memset(bargs, 0, sizeof(*bargs));
+ update_ioctl_balance_args(fs_info, bargs);
+ }
+
+ __cancel_balance(fs_info);
+
+ return ret;
+out:
+ kfree(bctl);
return ret;
}