On Mon, Jan 29, 2024 at 05:49:34PM +0100, Christoph Hellwig wrote: > On Tue, Jan 23, 2024 at 02:26:48PM +0100, Christian Brauner wrote: > > Make it possible to detected a block device that was opened with > > restricted write access solely based on its file operations that it was > > opened with. This avoids wasting an FMODE_* flag. > > > > def_blk_fops isn't needed to check whether something is a block device > > checking the inode type is enough for that. And def_blk_fops_restricted > > can be kept private to the block layer. > > I agree with not wasting a FMODE_* flag, but I also really hate > duplicating the file operations. I don't think it's that bad and is temporary until we can unconditionally disable writing to mounted block devices. Until then we can place all of this under #if IS_ENABLED(CONFIG_BLK_DEV_WRITE_MOUNTED) in a single location in block/fops.c so its nicely encapsulated and confined. > I went to search for a good place to stash this information and ended up > at the f_version field in struct file. That one is never touched by the > VFS proper but just the file system and a few lseek helpers. The > latter currently happen to be used by block devices unfortunately, > but it seem like moving the f_version clearing into the few filesystem > actualy using it would be good code hygiene anyway. Kinda like choosing between pest and cholera. I think that the f_op solution is nicer. Overloading f_version is not something I feel I have the stomach for. The cleanup itself might still be worth it ofc.
