On Wed, May 14, 2025 at 02:38:05PM +0100, Matthew Wilcox wrote: > On Tue, May 13, 2025 at 11:51:25PM -0400, Theodore Ts'o wrote: > > I understand that it would be a lot more inconvenient change the > > function signature of write_begin() to pass through iocb->ki_fags via > > a new parameter. But I think that probably is the best way to go. > > I'd suggest that passing in iocb rather than file is the way to go. > Most callers of ->write_begin already pass NULL as the first argument so > would not need to change. i915/gem passes a non-NULL file, but it only > operates on shmem and shmem does not use the file argument, so they can > pass NULL instead. i915/gem needs to stop using write_begin/end and just do an iter_write. Someone who has the hardware and/or CI setup needs to figure out if vfs_write and kernel_write is fine, or this is magic enough to skip checks and protection and go straight to callig ->iter_write. > fs/buffer.c simply passes through the file passed > to write_begin and can be changed to pass through the iocb passed in. > exfat_extend_valid_size() has an iocb in its caller and can pass in the > iocb instead. generic_perform_write() has an iocb. And we really need to stop theading this through the address_space ops because it's not a generic method but a callback for the file system..
