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 are used.
Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
---
fs/btrfs/ioctl.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index fa1b78cf25f6..5ddbacf67e95 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4000,6 +4000,8 @@ static long btrfs_ioctl_trans_start(struct file *file)
struct btrfs_trans_handle *trans;
int ret;
+ WARN_ON_ONCE(1);
+
ret = -EPERM;
if (!capable(CAP_SYS_ADMIN))
goto out;
@@ -4280,6 +4282,8 @@ long btrfs_ioctl_trans_end(struct file *file)
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
+ WARN_ON_ONCE(1);
+
trans = file->private_data;
if (!trans)
return -EINVAL;
--
2.7.4
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