On Wed, Jan 06, 2010 at 11:48:14PM +0800, Christoph Hellwig wrote:
> On Wed, Jan 06, 2010 at 02:55:26PM +0800, Wu Fengguang wrote:
> > The O_* bit numbers are defined in 20+ arch/*, and hence can silently
> > overlap. Add a boot time check to ensure the uniqueness as suggested
> > by David Miller.
>
> The right fix is to stop overlyaing the FMODE_ flags into the O_
> namespace. Al has been working towards this.
I thinks they are orthogonal problems -- this patch watches for the
possible conflicting O_* in so many archs.
Anyway here is the new version without the FMODE_ and O_RANDOM.
Thanks,
Fengguang
---
fs: O_* bit numbers uniqueness check
The O_* bit numbers are defined in 20+ arch/*, and hence can silently
overlap. Add a boot time check to ensure the uniqueness as suggested
by David Miller.
v4: use the nice hweight_long() as suggested by Jamie
split O_SYNC to (__O_SYNC | O_DSYNC) as suggested by Andreas
take away FMODE_* and O_RANDOM
v3: change to BUILD_BUG_ON() as suggested by Roland
CC: David Miller <davem@xxxxxxxxxxxxx>
CC: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
CC: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
CC: Christoph Hellwig <hch@xxxxxxxxxxxxx>
CC: Eric Paris <eparis@xxxxxxxxxx>
CC: Roland Dreier <rdreier@xxxxxxxxx>
CC: Jamie Lokier <jamie@xxxxxxxxxxxxx>
CC: Andreas Schwab <schwab@xxxxxxxxxxxxxx>
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
fs/fcntl.c | 14 ++++++++++++--
include/asm-generic/fcntl.h | 2 ++
2 files changed, 14 insertions(+), 2 deletions(-)
--- linux.orig/fs/fcntl.c 2010-01-09 11:02:57.000000000 +0800
+++ linux/fs/fcntl.c 2010-01-09 21:36:16.000000000 +0800
@@ -709,11 +709,21 @@ void kill_fasync(struct fasync_struct **
}
EXPORT_SYMBOL(kill_fasync);
-static int __init fasync_init(void)
+static int __init fcntl_init(void)
{
+ /* please add new bits here to ensure allocation uniqueness */
+ BUILD_BUG_ON(17 != hweight_long(
+ O_RDONLY | O_WRONLY | O_RDWR |
+ O_CREAT | O_EXCL | O_NOCTTY |
+ O_TRUNC | O_APPEND | O_NONBLOCK |
+ __O_SYNC | O_DSYNC | FASYNC |
+ O_DIRECT | O_LARGEFILE | O_DIRECTORY |
+ O_NOFOLLOW | O_NOATIME | O_CLOEXEC
+ ));
+
fasync_cache = kmem_cache_create("fasync_cache",
sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
return 0;
}
-module_init(fasync_init)
+module_init(fcntl_init)
--- linux.orig/include/asm-generic/fcntl.h 2010-01-09 11:02:57.000000000 +0800
+++ linux/include/asm-generic/fcntl.h 2010-01-09 12:23:17.000000000 +0800
@@ -4,6 +4,8 @@
#include <linux/types.h>
/*
+ * When introducing new O_* bits, please check its uniqueness in fcntl_init().
+ *
* FMODE_EXEC is 0x20
* FMODE_NONOTIFY is 0x1000000
* These cannot be used by userspace O_* until internal and external open
--
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