Messages in this thread | | | Date | Thu, 13 Nov 2014 22:14:41 +0000 | From | Al Viro <> | Subject | Re: [PATCH] btrfs: Don't check for file->private_data on open(). It is set by the core. |
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On Wed, Nov 12, 2014 at 07:34:50PM +0100, Martin Kepplinger wrote:
> > Btrfs uses this in the transaction start ioctl to record the transaction > > handle being started. Ceph is the main user of the ioctl, and we could > > setup a hash table if needed. But which call path in miscdevice is > > doing this? > > > > With your patch in place, btrfs would end up overwriting the miscdevice > > private_data field, which would probably cause problems. > > > > -chris > > > > I think i was mistaken, sorry. misc_open() used to set > file->private_data _only_ if you use set .open in struct file_operations. > > In current -next this changed and file->private_data is set to struct > miscdevice on a (userspace's) open call (misc_open()) just in any case. > > You do set .open so this wouldn't affect you and this patch can be ignored.
More to the point, this function is not reachable from anything in file_operations of any miscdevice. btrfs_ioctl != btrfs_control_ioctl...
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