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>
---
I rebased the patch on Sage''s fix, so you don''t have to rebase
it
by yourself.
---
fs/btrfs/ioctl.c | 44 +++++++++++++++++++++++++++-----------------
fs/btrfs/ioctl.h | 14 +++++++++-----
2 files changed, 36 insertions(+), 22 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 7cc2e8e..f87552a 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -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);
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 17c99eb..c344d12 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -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
--
1.6.3
--
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