Commit a7e99c69 authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

Btrfs: allow for canceling restriper 



Implement an ioctl for canceling restriper.  Currently we wait until
relocation of the current block group is finished, in future this can be
done by triggering a commit.  Balance item is deleted and no memory
about the interrupted balance is kept.

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent 837d5b6e

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -1216,6 +1216,7 @@ struct btrfs_fs_info { 
	struct mutex balance_mutex;

	atomic_t balance_running;

	atomic_t balance_pause_req;

	atomic_t balance_cancel_req;

	struct btrfs_balance_control *balance_ctl;

	wait_queue_head_t balance_wait_q;

fs/btrfs/disk-io.c

+1 −0
Original line number Diff line number Diff line
@@ -2006,6 +2006,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, 
	mutex_init(&fs_info->balance_mutex);

	atomic_set(&fs_info->balance_running, 0);

	atomic_set(&fs_info->balance_pause_req, 0);

	atomic_set(&fs_info->balance_cancel_req, 0);

	fs_info->balance_ctl = NULL;

	init_waitqueue_head(&fs_info->balance_wait_q);

fs/btrfs/ioctl.c

+4 −0
Original line number Diff line number Diff line
@@ -3076,6 +3076,8 @@ void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, 
		bargs->state |= BTRFS_BALANCE_STATE_RUNNING;

	if (atomic_read(&fs_info->balance_pause_req))

		bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;

	if (atomic_read(&fs_info->balance_cancel_req))

		bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;



	memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));

	memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
@@ -3157,6 +3159,8 @@ static long btrfs_ioctl_balance_ctl(struct btrfs_root *root, int cmd) 
	switch (cmd) {

	case BTRFS_BALANCE_CTL_PAUSE:

		return btrfs_pause_balance(root->fs_info);

	case BTRFS_BALANCE_CTL_CANCEL:

		return btrfs_cancel_balance(root->fs_info);

	}



	return -EINVAL;

fs/btrfs/ioctl.h

+2 −0
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ struct btrfs_ioctl_fs_info_args { 


/* balance control ioctl modes */

#define BTRFS_BALANCE_CTL_PAUSE		1

#define BTRFS_BALANCE_CTL_CANCEL	2



/*

 * this is packed, because it should be exactly the same as its disk
@@ -142,6 +143,7 @@ struct btrfs_balance_progress { 


#define BTRFS_BALANCE_STATE_RUNNING	(1ULL << 0)

#define BTRFS_BALANCE_STATE_PAUSE_REQ	(1ULL << 1)

#define BTRFS_BALANCE_STATE_CANCEL_REQ	(1ULL << 2)



struct btrfs_ioctl_balance_args {

	__u64 flags;				/* in/out */

fs/btrfs/volumes.c

+44 −3
Original line number Diff line number Diff line
@@ -2492,7 +2492,8 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info) 
	key.type = BTRFS_CHUNK_ITEM_KEY;



	while (1) {

		if (atomic_read(&fs_info->balance_pause_req)) {

		if (atomic_read(&fs_info->balance_pause_req) ||

		    atomic_read(&fs_info->balance_cancel_req)) {

			ret = -ECANCELED;

			goto error;

		}
@@ -2560,7 +2561,10 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info) 


static inline int balance_need_close(struct btrfs_fs_info *fs_info)

{

	return atomic_read(&fs_info->balance_pause_req) == 0;

	/* cancel requested || normal exit path */

	return atomic_read(&fs_info->balance_cancel_req) ||

		(atomic_read(&fs_info->balance_pause_req) == 0 &&

		 atomic_read(&fs_info->balance_cancel_req) == 0);

}



static void __cancel_balance(struct btrfs_fs_info *fs_info)
@@ -2586,7 +2590,8 @@ int btrfs_balance(struct btrfs_balance_control *bctl, 
	int ret;



	if (btrfs_fs_closing(fs_info) ||

	    atomic_read(&fs_info->balance_pause_req)) {

	    atomic_read(&fs_info->balance_pause_req) ||

	    atomic_read(&fs_info->balance_cancel_req)) {

		ret = -EINVAL;

		goto out;

	}
@@ -2832,6 +2837,42 @@ int btrfs_pause_balance(struct btrfs_fs_info *fs_info) 
	return ret;

}



int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)

{

	mutex_lock(&fs_info->balance_mutex);

	if (!fs_info->balance_ctl) {

		mutex_unlock(&fs_info->balance_mutex);

		return -ENOTCONN;

	}



	atomic_inc(&fs_info->balance_cancel_req);

	/*

	 * if we are running just wait and return, balance item is

	 * deleted in btrfs_balance in this case

	 */

	if (atomic_read(&fs_info->balance_running)) {

		mutex_unlock(&fs_info->balance_mutex);

		wait_event(fs_info->balance_wait_q,

			   atomic_read(&fs_info->balance_running) == 0);

		mutex_lock(&fs_info->balance_mutex);

	} else {

		/* __cancel_balance needs volume_mutex */

		mutex_unlock(&fs_info->balance_mutex);

		mutex_lock(&fs_info->volume_mutex);

		mutex_lock(&fs_info->balance_mutex);



		if (fs_info->balance_ctl)

			__cancel_balance(fs_info);



		mutex_unlock(&fs_info->volume_mutex);

	}



	BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));

	atomic_dec(&fs_info->balance_cancel_req);

	mutex_unlock(&fs_info->balance_mutex);

	return 0;

}



/*

 * shrinking a device means finding all of the device extents past

 * the new size, and then following the back refs to the chunks.