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Btrfs: add basic restriper infrastructure

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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>
This commit is contained in:
Ilya Dryomov
2012-01-16 22:04:47 +02:00
parent 10ea00f55a
commit c9e9f97bdf
6 changed files with 281 additions and 41 deletions
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120
fs/btrfs/volumes.c
View File

@ -1282,7 +1282,6 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
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 @@ error_close:
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 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
}
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 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
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 @@ error:
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 @@ error:
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 @@ static u64 div_factor(u64 num, int factor)
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 @@ int btrfs_balance(struct btrfs_root *dev_root)
* 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 @@ int btrfs_balance(struct btrfs_root *dev_root)
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;
}