Re: [PATCHv2 1/1] vfs: renumber FMODE_NONOTIFY and add to uniqueness check

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

Hello Andrew,

could you, please, consider the patch proposed in
https://lkml.org/lkml/2014/11/24/196
for inclusion into the mm-tree.

This 2nd version of the patch considers the review comments in the 
thread starting at https://lkml.org/lkml/2014/11/21/141.

Best regards

Heinrich Schuchardt


On 24.11.2014 12:30, Jan Kara wrote:
> On Mon 24-11-14 11:23:19, David Drysdale wrote:
>> Fix clashing values for O_PATH and FMODE_NONOTIFY on sparc.
>> The clashing O_PATH value was added in 5229645bdc35f1cc43eb ("vfs: add
>> nonconflicting values for O_PATH") but this can't be changed as it
>> is user-visible.
>>
>> FMODE_NONOTIFY is only used internally in the kernel, but it is in
>> the same numbering space as the other O_* flags, as indicated by the
>> comment at the top of include/uapi/asm-generic/fcntl.h (and its use
>> in fs/notify/fanotify/fanotify_user.c).  So renumber it to avoid
>> the clash.
>>
>> All of this has happened before (12ed2e36c98aec6c4155, "fanotify:
>> FMODE_NONOTIFY and __O_SYNC in sparc conflict"), and all of this
>> will happen again -- so update the uniqueness check in fcntl_init()
>> to include __FMODE_NONOTIFY.
>>
>> Signed-off-by: David Drysdale <drysdale@google.com>
>> Acked-by: David S. Miller <davem@davemloft.net>
>    Looks good. You can add:
> Acked-by: Jan Kara <jack@suse.cz>
>
> 								Honza
>
>> ---
>>   fs/fcntl.c                       | 5 +++--
>>   include/linux/fs.h               | 2 +-
>>   include/uapi/asm-generic/fcntl.h | 2 +-
>>   3 files changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/fcntl.c b/fs/fcntl.c
>> index 99d440a4a6ba..ee85cd4e136a 100644
>> --- a/fs/fcntl.c
>> +++ b/fs/fcntl.c
>> @@ -740,14 +740,15 @@ static int __init fcntl_init(void)
>>   	 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
>>   	 * is defined as O_NONBLOCK on some platforms and not on others.
>>   	 */
>> -	BUILD_BUG_ON(20 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
>> +	BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
>>   		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	|
>> -		__FMODE_EXEC	| O_PATH	| __O_TMPFILE
>> +		__FMODE_EXEC	| O_PATH	| __O_TMPFILE	|
>> +		__FMODE_NONOTIFY
>>   		));
>>
>>   	fasync_cache = kmem_cache_create("fasync_cache",
>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>> index 9ab779e8a63c..fc1c2488adbc 100644
>> --- a/include/linux/fs.h
>> +++ b/include/linux/fs.h
>> @@ -134,7 +134,7 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
>>   #define FMODE_CAN_WRITE         ((__force fmode_t)0x40000)
>>
>>   /* File was opened by fanotify and shouldn't generate fanotify events */
>> -#define FMODE_NONOTIFY		((__force fmode_t)0x1000000)
>> +#define FMODE_NONOTIFY		((__force fmode_t)0x4000000)
>>
>>   /*
>>    * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
>> diff --git a/include/uapi/asm-generic/fcntl.h b/include/uapi/asm-generic/fcntl.h
>> index 7543b3e51331..e063effe0cc1 100644
>> --- a/include/uapi/asm-generic/fcntl.h
>> +++ b/include/uapi/asm-generic/fcntl.h
>> @@ -5,7 +5,7 @@
>>
>>   /*
>>    * FMODE_EXEC is 0x20
>> - * FMODE_NONOTIFY is 0x1000000
>> + * FMODE_NONOTIFY is 0x4000000
>>    * These cannot be used by userspace O_* until internal and external open
>>    * flags are split.
>>    * -Eric Paris
>> --
>> 2.1.0.rc2.206.gedb03e5
>>