lkml.org 
[lkml]   [2021]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 08/18] MM: Add AS_CAN_DIO mapping flag
On Fri, Dec 17, 2021 at 10:48:23AM +1100, NeilBrown wrote:
> Currently various places test if direct IO is possible on a file by
> checking for the existence of the direct_IO address space operation.
> This is a poor choice, as the direct_IO operation may not be used - it is
> only used if the generic_file_*_iter functions are called for direct IO
> and some filesystems - particularly NFS - don't do this.
>
> Instead, introduce a new mapping flag: AS_CAN_DIO and change the various
> places to check this (avoiding a pointer dereference).
> unlock_new_inode() will set this flag if ->direct_IO is present, so
> filesystems do not need to be changed.
>
> NFS *is* changed, to set the flag explicitly and discard the direct_IO
> entry in the address_space_operations for files.

For other can flags related to file operations we usuall stash them into
file->f_mode. Any reason to treat this different?

\
 
 \ /
  Last update: 2021-12-21 09:46    [W:0.220 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site