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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: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Li Zefan 2010-12-10 06:41:56 +00:00 committed by Chris Mason
parent 914ee295af
commit fdfb1e4f6c
2 changed files with 36 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
fs/btrfs/ioctl.c
View File

@ -947,31 +947,41 @@ out:
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;
name = async_vol_args->name;
fd = async_vol_args->fd;
async_vol_args->name[BTRFS_SNAPSHOT_NAME_MAX] = '\0';
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';
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);

14
fs/btrfs/ioctl.h
View File

@ -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