btrfs: Deprecate userspace transaction ioctls
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@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ move the warning past perm checks, keep the has-been-printed state;
we're ok with just one warning over all filesystems ]
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 496e873b..4cfc3d4 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3967,11 +3967,22 @@
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
int ret;
+ 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;