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Commit 02db0844 authored by Josef Bacik's avatar Josef Bacik Committed by Chris Mason
Browse files

Btrfs: add DEVICE_READY ioctl 



This will be used in conjunction with btrfs device ready <dev>.  This is
needed for initrd's to have a nice and lightweight way to tell if all of the
devices needed for a file system are in the cache currently.  This keeps
them from having to do mount+sleep loops waiting for devices to show up.
Thanks,

Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
parent 96c3f433

fs/btrfs/ioctl.h

+2 −1
Original line number Diff line number Diff line
@@ -363,7 +363,8 @@ struct btrfs_ioctl_get_dev_stats { 
					struct btrfs_ioctl_ino_path_args)

#define BTRFS_IOC_LOGICAL_INO _IOWR(BTRFS_IOCTL_MAGIC, 36, \

					struct btrfs_ioctl_ino_path_args)

#define BTRFS_IOC_DEVICES_READY _IOR(BTRFS_IOCTL_MAGIC, 39, \

				     struct btrfs_ioctl_vol_args)

#define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \

				      struct btrfs_ioctl_get_dev_stats)



#endif

fs/btrfs/super.c

+7 −0
Original line number Diff line number Diff line
@@ -1462,6 +1462,13 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, 
		ret = btrfs_scan_one_device(vol->name, FMODE_READ,

					    &btrfs_fs_type, &fs_devices);

		break;

	case BTRFS_IOC_DEVICES_READY:

		ret = btrfs_scan_one_device(vol->name, FMODE_READ,

					    &btrfs_fs_type, &fs_devices);

		if (ret)

			break;

		ret = !(fs_devices->num_devices == fs_devices->total_devices);

		break;

	}



	kfree(vol);

fs/btrfs/volumes.c

+8 −1
Original line number Diff line number Diff line
@@ -429,6 +429,7 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig) 
	mutex_init(&fs_devices->device_list_mutex);

	fs_devices->latest_devid = orig->latest_devid;

	fs_devices->latest_trans = orig->latest_trans;

	fs_devices->total_devices = orig->total_devices;

	memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));



	/* We have held the volume lock, it is safe to get the devices. */
@@ -739,6 +740,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, 
	int ret;

	u64 devid;

	u64 transid;

	u64 total_devices;



	flags |= FMODE_EXCL;

	bdev = blkdev_get_by_path(path, flags, holder);
@@ -760,6 +762,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, 
	disk_super = (struct btrfs_super_block *)bh->b_data;

	devid = btrfs_stack_device_id(&disk_super->dev_item);

	transid = btrfs_super_generation(disk_super);

	total_devices = btrfs_super_num_devices(disk_super);

	if (disk_super->label[0])

		printk(KERN_INFO "device label %s ", disk_super->label);

	else
@@ -767,7 +770,8 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, 
	printk(KERN_CONT "devid %llu transid %llu %s\n",

	       (unsigned long long)devid, (unsigned long long)transid, path);

	ret = device_list_add(path, disk_super, devid, fs_devices_ret);



	if (!ret && fs_devices_ret)

		(*fs_devices_ret)->total_devices = total_devices;

	brelse(bh);

error_close:

	mutex_unlock(&uuid_mutex);
@@ -1433,6 +1437,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path) 
	list_del_rcu(&device->dev_list);



	device->fs_devices->num_devices--;

	device->fs_devices->total_devices--;



	if (device->missing)

		root->fs_info->fs_devices->missing_devices--;
@@ -1550,6 +1555,7 @@ static int btrfs_prepare_sprout(struct btrfs_root *root) 
	fs_devices->seeding = 0;

	fs_devices->num_devices = 0;

	fs_devices->open_devices = 0;

	fs_devices->total_devices = 0;

	fs_devices->seed = seed_devices;



	generate_random_uuid(fs_devices->fsid);
@@ -1749,6 +1755,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path) 
	root->fs_info->fs_devices->num_devices++;

	root->fs_info->fs_devices->open_devices++;

	root->fs_info->fs_devices->rw_devices++;

	root->fs_info->fs_devices->total_devices++;

	if (device->can_discard)

		root->fs_info->fs_devices->num_can_discard++;

	root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;

fs/btrfs/volumes.h

+1 −0
Original line number Diff line number Diff line
@@ -126,6 +126,7 @@ struct btrfs_fs_devices { 
	u64 missing_devices;

	u64 total_rw_bytes;

	u64 num_can_discard;

	u64 total_devices;

	struct block_device *latest_bdev;



	/* all of the devices in the FS, protected by a mutex