lkml.org 
[lkml]   [2020]   [Jun]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] vfs: don't unnecessarily clone write access for writable fds
On Thu, Jun 11, 2020 at 09:05:34AM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> There's no need for mnt_want_write_file() to increment mnt_writers when
> the file is already open for writing, provided that
> mnt_drop_write_file() is changed to conditionally decrement it.
>
> We seem to have ended up in the current situation because
> mnt_want_write_file() used to be paired with mnt_drop_write(), due to
> mnt_drop_write_file() not having been added yet. So originally
> mnt_want_write_file() had to always increment mnt_writers.
>
> But later mnt_drop_write_file() was added, and all callers of
> mnt_want_write_file() were paired with it. This makes the compatibility
> between mnt_want_write_file() and mnt_drop_write() no longer necessary.
>
> Therefore, make __mnt_want_write_file() and __mnt_drop_write_file() skip
> incrementing mnt_writers on files already open for writing. This
> removes the only caller of mnt_clone_write(), so remove that too.
>
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Al, any thoughts on this patch?

- Eric

\
 
 \ /
  Last update: 2020-06-29 22:37    [W:0.030 / U:6.824 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site