Re: [RFC][PATCH v4] readahead: introduce O_RANDOM for POSIX_FADV_RANDOM

[Wu Fengguang <fengguang.wu@intel.com>]

On Tue, Jan 05, 2010 at 10:28:24AM +0800, Stephen Rothwell wrote:
> Hi Fengguang,
> 
> On Tue, 5 Jan 2010 10:26:50 +0800 Wu Fengguang <fengguang.wu@intel.com> wrote:
> >
> > Where is it? I cannot grep find one in arch/.
> > There is one defined in include/asm-generic/fcntl.h:
> > 
> > #ifndef O_SYNC
> > #define __O_SYNC        04000000
> > #define O_SYNC          (__O_SYNC|O_DSYNC)
> > #endif
> > 
> > However it has one less '0' :)
> 
> Search for 0x800000 ...

Thanks, I got it..

Does that mean __O_SYNC would be _accidentally_ masked out in
__dentry_open() by the newly introduced fanotify bit?

        f->f_flags = (flags & ~(FMODE_EXEC | FMODE_NONOTIFY));

The above line is added in commit f67cee7b50b004357be383,
and can be fixed by the below patch.

Eric, what do you think?

Thanks,
Fengguang
---

 include/asm-generic/fcntl.h |    2 +-
 include/linux/fs.h          |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- linux.orig/include/asm-generic/fcntl.h	2010-01-05 10:42:36.000000000 +0800
+++ linux/include/asm-generic/fcntl.h	2010-01-05 10:42:57.000000000 +0800
@@ -5,7 +5,7 @@
 
 /*
  * FMODE_EXEC is 0x20
- * FMODE_NONOTIFY is 0x800000
+ * FMODE_NONOTIFY is 0x1000000
  * These cannot be used by userspace O_* until internal and external open
  * flags are split.
  * -Eric Paris
--- linux.orig/include/linux/fs.h	2010-01-05 10:40:33.000000000 +0800
+++ linux/include/linux/fs.h	2010-01-05 10:42:07.000000000 +0800
@@ -88,7 +88,7 @@ struct inodes_stat_t {
 #define FMODE_NOCMTIME		((__force fmode_t)2048)
 
 /* File was opened by fanotify and shouldn't generate fanotify events */
-#define FMODE_NONOTIFY		((__force fmode_t)8388608)
+#define FMODE_NONOTIFY		((__force fmode_t)0x1000000)
 
 /*
  * The below are the various read and write types that we support. Some of