On Wed, Jul 26, 2017 at 11:26:28AM +0300, Nikolay Borisov wrote:
> Userspace transactions were introduced in commit
> 6bf13c0cc833 ("Btrfs: transaction ioctls") to provide semantics that Ceph's
> object store required. However, things have changed significantly since then,
> to the point where btrfs is no longer suitable as a backend for ceph and in fact
> it's actively advised against such usages. Considering this, there doesn't
> seem to be a widespread, legit use case of userspace transaction. They also
> clutter the file->private pointer.
>
> So to end the agony let's nuke the userspace transaction ioctls. As a first
> step let's give time for people to voice their objection by just WARN()ining
> when the userspace transaction is used.
>
> Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
> ---
> fs/btrfs/ioctl.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index fa1b78cf25f6..10d78d71df96 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -4000,6 +4000,12 @@ static long btrfs_ioctl_trans_start(struct file *file)
> struct btrfs_trans_handle *trans;
> int ret;
>
> + btrfs_warn(fs_info, "Userspace transaction mechanism is considered
> + deprecated and slated to be removed in the near future "
> + "(1 or 2 releases). If you have a valid use case please
> + speak up on the mailing list");
> + WARN_ON_ONCE(1);
> +
> ret = -EPERM;
> if (!capable(CAP_SYS_ADMIN))
> goto out;
The warning must go after the permission checks and warn really just only once,
so we need to keep the local state anyway.
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3967,17 +3967,22 @@ static long btrfs_ioctl_trans_start(struct file *file)
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
int ret;
-
- btrfs_warn(fs_info, "Userspace transaction mechanism is considered
- deprecated and slated to be removed in the near future "
- "(1 or 2 releases). If you have a valid use case please
- speak up on the mailing list");
- WARN_ON_ONCE(1);
+ static bool warned = false;
ret = -EPERM;
if (!capable(CAP_SYS_ADMIN))
goto out;
+ if (!warned) {
+ btrfs_warn(fs_info,
+ "Userspace transaction mechanism is considered "
+ "deprecated and slated to be removed in 4.17. "
+ "If you have a valid use case please "
+ "speak up on the mailing list");
+ WARN_ON(1);
+ warned = true;
+ }
+
ret = -EINPROGRESS;
if (file->private_data)
goto out;
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
