Commit efc0e69c authored by Nikolay Borisov's avatar Nikolay Borisov Committed by David Sterba
Browse files

btrfs: introduce exclusive operation BALANCE_PAUSED state 



Current set of exclusive operation states is not sufficient to handle
all practical use cases. In particular there is a need to be able to add
a device to a filesystem that have paused balance. Currently there is no
way to distinguish between a running and a paused balance. Fix this by
introducing BTRFS_EXCLOP_BALANCE_PAUSED which is going to be set in 2
occasions:

1. When a filesystem is mounted with skip_balance and there is an
   unfinished balance it will now be into BALANCE_PAUSED instead of
   simply BALANCE state.

2. When a running balance is paused.

Signed-off-by: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent d96b3424

fs/btrfs/ctree.h

+4 −0
Original line number Diff line number Diff line
@@ -611,6 +611,7 @@ enum { 
 */

enum btrfs_exclusive_operation {

	BTRFS_EXCLOP_NONE,

	BTRFS_EXCLOP_BALANCE_PAUSED,

	BTRFS_EXCLOP_BALANCE,

	BTRFS_EXCLOP_DEV_ADD,

	BTRFS_EXCLOP_DEV_REMOVE,
@@ -3321,6 +3322,9 @@ bool btrfs_exclop_start_try_lock(struct btrfs_fs_info *fs_info, 
				 enum btrfs_exclusive_operation type);

void btrfs_exclop_start_unlock(struct btrfs_fs_info *fs_info);

void btrfs_exclop_finish(struct btrfs_fs_info *fs_info);

void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,

			  enum btrfs_exclusive_operation op);





/* file.c */

int __init btrfs_auto_defrag_init(void);

fs/btrfs/ioctl.c

+24 −0
Original line number Diff line number Diff line
@@ -414,6 +414,29 @@ void btrfs_exclop_finish(struct btrfs_fs_info *fs_info) 
	sysfs_notify(&fs_info->fs_devices->fsid_kobj, NULL, "exclusive_operation");

}



void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,

			  enum btrfs_exclusive_operation op)

{

	switch (op) {

	case BTRFS_EXCLOP_BALANCE_PAUSED:

		spin_lock(&fs_info->super_lock);

		ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||

		       fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD);

		fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE_PAUSED;

		spin_unlock(&fs_info->super_lock);

		break;

	case BTRFS_EXCLOP_BALANCE:

		spin_lock(&fs_info->super_lock);

		ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);

		fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE;

		spin_unlock(&fs_info->super_lock);

		break;

	default:

		btrfs_warn(fs_info,

			"invalid exclop balance operation %d requested", op);

	}

}



static int btrfs_ioctl_getversion(struct file *file, int __user *arg)

{

	struct inode *inode = file_inode(file);
@@ -4056,6 +4079,7 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg) 
			spin_lock(&fs_info->balance_lock);

			bctl->flags |= BTRFS_BALANCE_RESUME;

			spin_unlock(&fs_info->balance_lock);

			btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE);



			goto do_balance;

		}

fs/btrfs/volumes.c

+8 −2
Original line number Diff line number Diff line
@@ -4394,8 +4394,10 @@ int btrfs_balance(struct btrfs_fs_info *fs_info, 
	ret = __btrfs_balance(fs_info);



	mutex_lock(&fs_info->balance_mutex);

	if (ret == -ECANCELED && atomic_read(&fs_info->balance_pause_req))

	if (ret == -ECANCELED && atomic_read(&fs_info->balance_pause_req)) {

		btrfs_info(fs_info, "balance: paused");

		btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE_PAUSED);

	}

	/*

	 * Balance can be canceled by:

	 *
@@ -4471,6 +4473,10 @@ int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info) 
		return 0;

	}



	spin_lock(&fs_info->super_lock);

	ASSERT(fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED);

	fs_info->exclusive_operation = BTRFS_EXCLOP_BALANCE;

	spin_unlock(&fs_info->super_lock);

	/*

	 * A ro->rw remount sequence should continue with the paused balance

	 * regardless of who pauses it, system or the user as of now, so set
@@ -4539,7 +4545,7 @@ int btrfs_recover_balance(struct btrfs_fs_info *fs_info) 
	 * is in a paused state and must have fs_info::balance_ctl properly

	 * set up.

	 */

	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE))

	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE_PAUSED))

		btrfs_warn(fs_info,

	"balance: cannot set exclusive op status, resume manually");