Re: [PATCH 1/3] mm/filemap: initialize fsdata with iocb->ki_flags

["Theodore Ts'o" <tytso@mit.edu>]

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.  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.

Mmm, nice!  I agree, that's probably the way to go.

There might be some callers if write_begin() that might require some
restructing because they don't have an iocb.  For example,
shmem_pwrite() in drivers/gpu/i915/gem/i915_gem_shmem.c came up when I
did a quick grep.

     	      	     	    	     	     - Ted