bio, fs: update RWA_MASK, READA and SWRITE to match the corresponding BIO_RW_* bits

08-03-2010, 09:53 AM

Commit a82afdf (block: use the same failfast bits for bio and request)
moved BIO_RW_* bits around such that they match up with REQ_* bits.
Unfortunately, fs.h hard coded RW_MASK, RWA_MASK, READ, WRITE, READA
and SWRITE as 0, 1, 2 and 3, and expected them to match with BIO_RW_*
bits. READ/WRITE didn't change but BIO_RW_AHEAD was moved to bit 4
instead of bit 1, breaking RWA_MASK, READA and SWRITE.

This patch updates RWA_MASK, READA and SWRITE such that they match the
BIO_RW_* bits again. A follow up patch will update the definitions to
directly use BIO_RW_* bits so that this kind of breakage won't happen
again.

Neil also spotted missing RWA_MASK conversion.

Stable: The offending commit a82afdf was released with v2.6.32, so
this patch should be applied to all kernels since then but it must
_NOT_ be applied to kernels earlier than that.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-bisected-by: Vladislav Bolkhovitin <vst@vlnb.net>
Root-caused-by: Neil Brown <neilb@suse.de>
Cc: Jens Axobe <axboe@kernel.dk>
Cc: stable@kernel.org
---
Here's the regenerated version also w/ the missing RWA_MASK conversion
Neil spotted.

Thanks.

include/linux/fs.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

Index: work/include/linux/fs.h
================================================== =================
--- work.orig/include/linux/fs.h
+++ work/include/linux/fs.h
@@ -145,12 +145,12 @@ struct inodes_stat_t {
*
*/
#define RW_MASK 1
-#define RWA_MASK 2
+#define RWA_MASK 16

#define READ 0
#define WRITE 1
-#define READA 2 /* readahead - don't block if no resources */
-#define SWRITE 3 /* for ll_rw_block() - wait for buffer lock */
+#define READA 16 /* readahead - don't block if no resources */
+#define SWRITE 17 /* for ll_rw_block(), wait for buffer lock */

#define READ_SYNC (READ | REQ_SYNC | REQ_UNPLUG)
#define READ_META (READ | REQ_META)

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08-03-2010, 11:15 AM

On 2010-08-03 11:53, Tejun Heo wrote:
> Commit a82afdf (block: use the same failfast bits for bio and request)
> moved BIO_RW_* bits around such that they match up with REQ_* bits.
> Unfortunately, fs.h hard coded RW_MASK, RWA_MASK, READ, WRITE, READA
> and SWRITE as 0, 1, 2 and 3, and expected them to match with BIO_RW_*
> bits. READ/WRITE didn't change but BIO_RW_AHEAD was moved to bit 4
> instead of bit 1, breaking RWA_MASK, READA and SWRITE.
>
> This patch updates RWA_MASK, READA and SWRITE such that they match the
> BIO_RW_* bits again. A follow up patch will update the definitions to
> directly use BIO_RW_* bits so that this kind of breakage won't happen
> again.
>
> Neil also spotted missing RWA_MASK conversion.
>
> Stable: The offending commit a82afdf was released with v2.6.32, so
> this patch should be applied to all kernels since then but it must
> _NOT_ be applied to kernels earlier than that.
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Reported-and-bisected-by: Vladislav Bolkhovitin <vst@vlnb.net>
> Root-caused-by: Neil Brown <neilb@suse.de>
> Cc: Jens Axobe <axboe@kernel.dk>
^^^^^

(Too) common typo :-)

Anyway, applied to for-2.6.36, thanks a lot.

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08-03-2010, 11:21 AM

On 2010-08-03 13:15, Jens Axboe wrote:
> On 2010-08-03 11:53, Tejun Heo wrote:
>> Commit a82afdf (block: use the same failfast bits for bio and request)
>> moved BIO_RW_* bits around such that they match up with REQ_* bits.
>> Unfortunately, fs.h hard coded RW_MASK, RWA_MASK, READ, WRITE, READA
>> and SWRITE as 0, 1, 2 and 3, and expected them to match with BIO_RW_*
>> bits. READ/WRITE didn't change but BIO_RW_AHEAD was moved to bit 4
>> instead of bit 1, breaking RWA_MASK, READA and SWRITE.
>>
>> This patch updates RWA_MASK, READA and SWRITE such that they match the
>> BIO_RW_* bits again. A follow up patch will update the definitions to
>> directly use BIO_RW_* bits so that this kind of breakage won't happen
>> again.
>>
>> Neil also spotted missing RWA_MASK conversion.
>>
>> Stable: The offending commit a82afdf was released with v2.6.32, so
>> this patch should be applied to all kernels since then but it must
>> _NOT_ be applied to kernels earlier than that.
>>
>> Signed-off-by: Tejun Heo <tj@kernel.org>
>> Reported-and-bisected-by: Vladislav Bolkhovitin <vst@vlnb.net>
>> Root-caused-by: Neil Brown <neilb@suse.de>
>> Cc: Jens Axobe <axboe@kernel.dk>
> ^^^^^
>
> (Too) common typo :-)
>
> Anyway, applied to for-2.6.36, thanks a lot.

Irk, we have an issue:

In file included from fs/coda/psdev.c:48:
include/linux/coda_psdev.h:91:1: warning: "REQ_WRITE" redefined
In file included from include/linux/fs.h:11,
from include/linux/proc_fs.h:5,
from fs/coda/psdev.c:31:
include/linux/blk_types.h:154:1: warning: this is the location of the previous definition

And from include/linux/coda_psdev.h:

#define REQ_ASYNC 0x1
#define REQ_READ 0x2
#define REQ_WRITE 0x4
#define REQ_ABORT 0x8

which unfortunately seem to not be under __KERNEL__ protection, but
there are things like wait_queue_head_t structs there as well so should
be safe to change.

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08-03-2010, 03:52 PM

(cc'ing CODA people)
Hello,

On 08/03/2010 01:21 PM, Jens Axboe wrote:
>>> Signed-off-by: Tejun Heo <tj@kernel.org>
>>> Reported-and-bisected-by: Vladislav Bolkhovitin <vst@vlnb.net>
>>> Root-caused-by: Neil Brown <neilb@suse.de>
>>> Cc: Jens Axobe <axboe@kernel.dk>
>> ^^^^^
>>
>> (Too) common typo :-)
>>
>> Anyway, applied to for-2.6.36, thanks a lot.

Oops, I'm sorry. Heh, it reminds me of misspelling Linus's last name
as Tolvards in a number of patches. :-)

> Irk, we have an issue:
>
> In file included from fs/coda/psdev.c:48:
> include/linux/coda_psdev.h:91:1: warning: "REQ_WRITE" redefined
> In file included from include/linux/fs.h:11,
> from include/linux/proc_fs.h:5,
> from fs/coda/psdev.c:31:
> include/linux/blk_types.h:154:1: warning: this is the location of the previous definition
>
> And from include/linux/coda_psdev.h:
>
> #define REQ_ASYNC 0x1
> #define REQ_READ 0x2
> #define REQ_WRITE 0x4
> #define REQ_ABORT 0x8
>
> which unfortunately seem to not be under __KERNEL__ protection, but
> there are things like wait_queue_head_t structs there as well so should
> be safe to change.

Yeah, I hate it when symbols in non-core code doesn't have proper
prefix. Prefixing CODA_ in front of those macros should do it. Jan
Harkes, would that work for CODA?

Thanks.

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tejun

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