Hi Chris,
Is this ioctl change destined for 2.6.37? If it (or something similar)
looks good it should probably be merged (independent of the rest of the
series) this time around before we're stuck with the current version.
Thanks-
sage
On Mon, 29 Nov 2010, Li Zefan wrote:
> So we don't have to add new structures as we create more ioctls
> for snapshots.
>
> Now to create async snapshot, set BTRFS_SNAPSHOT_CREATE_ASYNC bit of
> vol_arg_v2->flags, and then call ioctl(BTRFS_IOCT_SNAP_CREATE_V2).
>
> Note: this changes the async snapshot ioctl ABI, which was merged
> in .37 merge window, so we have to make this change into .37.
>
> Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
> ---
> fs/btrfs/ioctl.c | 34 +++++++++++++++++++++-------------
> fs/btrfs/ioctl.h | 12 ++++++++----
> 2 files changed, 29 insertions(+), 17 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 463d91b..d3f1a60 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -935,23 +935,31 @@ out:
>
> static noinline int btrfs_ioctl_snap_create(struct file *file,
> void __user *arg, int subvol,
> - int async)
> + bool 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;
> + bool async = false;
> 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) {
> + vol_args_v2 = memdup_user(arg, sizeof(*vol_args_v2));
> + if (IS_ERR(vol_args_v2))
> + return PTR_ERR(vol_args_v2);
>
> - 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_SNAPSHOT_CREATE_ASYNC) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + name = vol_args_v2->name;
> + fd = vol_args_v2->fd;
> + vol_args_v2->name[BTRFS_SNAPSHOT_NAME_MAX] = '\0';
> + if (vol_args_v2->flags & BTRFS_SNAPSHOT_CREATE_ASYNC)
> + async = true;
> } else {
> vol_args = memdup_user(arg, sizeof(*vol_args));
> if (IS_ERR(vol_args))
> @@ -966,13 +974,13 @@ static noinline int btrfs_ioctl_snap_create(struct file *file,
>
> if (!ret && async) {
> if (copy_to_user(arg +
> - offsetof(struct btrfs_ioctl_async_vol_args,
> + offsetof(struct btrfs_ioctl_vol_args_v2,
> transid), &transid, sizeof(transid)))
> return -EFAULT;
> }
> -
> +out:
> kfree(vol_args);
> - kfree(async_vol_args);
> + kfree(vol_args_v2);
>
> return ret;
> }
> @@ -2235,7 +2243,7 @@ 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);
> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
> index 17c99eb..bc70584 100644
> --- a/fs/btrfs/ioctl.h
> +++ b/fs/btrfs/ioctl.h
> @@ -30,10 +30,14 @@ 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_SNAPSHOT_CREATE_ASYNC (1ULL << 0)
> +
> +#define BTRFS_SNAPSHOT_NAME_MAX 4039
> +struct btrfs_ioctl_vol_args_v2 {
> __s64 fd;
> __u64 transid;
> + __u64 flags;
> + __u64 unused[4];
> char name[BTRFS_SNAPSHOT_NAME_MAX + 1];
> };
>
> @@ -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
> --
> 1.6.3
>
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