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Commit fdfb1e4f authored by Li Zefan's avatar Li Zefan Committed by Chris Mason
Browse files

Btrfs: Make async snapshot ioctl more generic 



If we had reserved some bytes in struct btrfs_ioctl_vol_args, we
wouldn't have to create a new structure for async snapshot creation.

Here we convert async snapshot ioctl to use a more generic ABI, as
we'll add more ioctls for snapshots/subvolumes in the future, readonly
snapshots for example.

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 914ee295

fs/btrfs/ioctl.c

+27 −17
Original line number Diff line number Diff line
@@ -947,31 +947,41 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file, 


static noinline int btrfs_ioctl_snap_create(struct file *file,

					    void __user *arg, int subvol,

					    int async)

					    int v2)

{

	struct btrfs_ioctl_vol_args *vol_args = NULL;

	struct btrfs_ioctl_async_vol_args *async_vol_args = NULL;

	struct btrfs_ioctl_vol_args_v2 *vol_args_v2 = NULL;

	char *name;

	u64 fd;

	u64 transid = 0;

	int ret;



	if (async) {

		async_vol_args = memdup_user(arg, sizeof(*async_vol_args));

		if (IS_ERR(async_vol_args))

			return PTR_ERR(async_vol_args);

	if (v2) {

		u64 transid = 0;

		u64 *ptr = NULL;



		vol_args_v2 = memdup_user(arg, sizeof(*vol_args_v2));

		if (IS_ERR(vol_args_v2))

			return PTR_ERR(vol_args_v2);



		if (vol_args_v2->flags & ~BTRFS_SUBVOL_CREATE_ASYNC) {

			ret = -EINVAL;

			goto out;

		}



		name = vol_args_v2->name;

		fd = vol_args_v2->fd;

		vol_args_v2->name[BTRFS_SUBVOL_NAME_MAX] = '\0';



		name = async_vol_args->name;

		fd = async_vol_args->fd;

		async_vol_args->name[BTRFS_SNAPSHOT_NAME_MAX] = '\0';

		if (vol_args_v2->flags & BTRFS_SUBVOL_CREATE_ASYNC)

			ptr = &transid;



		ret = btrfs_ioctl_snap_create_transid(file, name, fd,

						      subvol, &transid);

						      subvol, ptr);



		if (ret == 0 &&

		if (ret == 0 && ptr &&

		    copy_to_user(arg +

				 offsetof(struct btrfs_ioctl_async_vol_args,

					  transid), &transid, sizeof(transid)))

				 offsetof(struct btrfs_ioctl_vol_args_v2,

					  transid), ptr, sizeof(*ptr)))

			ret = -EFAULT;

	} else {

		vol_args = memdup_user(arg, sizeof(*vol_args));
@@ -984,9 +994,9 @@ static noinline int btrfs_ioctl_snap_create(struct file *file, 
		ret = btrfs_ioctl_snap_create_transid(file, name, fd,

						      subvol, NULL);

	}



out:

	kfree(vol_args);

	kfree(async_vol_args);

	kfree(vol_args_v2);



	return ret;

}
@@ -2248,7 +2258,7 @@ long btrfs_ioctl(struct file *file, unsigned int 
		return btrfs_ioctl_getversion(file, argp);

	case BTRFS_IOC_SNAP_CREATE:

		return btrfs_ioctl_snap_create(file, argp, 0, 0);

	case BTRFS_IOC_SNAP_CREATE_ASYNC:

	case BTRFS_IOC_SNAP_CREATE_V2:

		return btrfs_ioctl_snap_create(file, argp, 0, 1);

	case BTRFS_IOC_SUBVOL_CREATE:

		return btrfs_ioctl_snap_create(file, argp, 1, 0);

fs/btrfs/ioctl.h

+9 −5
Original line number Diff line number Diff line
@@ -30,11 +30,15 @@ struct btrfs_ioctl_vol_args { 
	char name[BTRFS_PATH_NAME_MAX + 1];

};



#define BTRFS_SNAPSHOT_NAME_MAX 4079

struct btrfs_ioctl_async_vol_args {

#define BTRFS_SUBVOL_CREATE_ASYNC	(1ULL << 0)



#define BTRFS_SUBVOL_NAME_MAX 4039

struct btrfs_ioctl_vol_args_v2 {

	__s64 fd;

	__u64 transid;

	char name[BTRFS_SNAPSHOT_NAME_MAX + 1];

	__u64 flags;

	__u64 unused[4];

	char name[BTRFS_SUBVOL_NAME_MAX + 1];

};



#define BTRFS_INO_LOOKUP_PATH_MAX 4080
@@ -187,6 +191,6 @@ struct btrfs_ioctl_space_args { 
				    struct btrfs_ioctl_space_args)

#define BTRFS_IOC_START_SYNC _IOR(BTRFS_IOCTL_MAGIC, 24, __u64)

#define BTRFS_IOC_WAIT_SYNC  _IOW(BTRFS_IOCTL_MAGIC, 22, __u64)

#define BTRFS_IOC_SNAP_CREATE_ASYNC _IOW(BTRFS_IOCTL_MAGIC, 23, \

				   struct btrfs_ioctl_async_vol_args)

#define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \

				   struct btrfs_ioctl_vol_args_v2)

#endif