linux-kernel - [PATCH 1/2 block#for-linus] bio, fs: update READA and SWRITE to match the corresponding BIO_RW

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4C56D259.8000504@kernel.org>
Date:	Mon, 02 Aug 2010 16:12:41 +0200
From:	Tejun Heo <tj@...nel.org>
To:	Jens Axboe <jens.axboe@...cle.com>, stable@...nel.org
CC:	Vladislav Bolkhovitin <vst@...b.net>,
	Bryan Mesich <bryan.mesich@...u.edu>,
	scst-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	linux-raid@...r.kernel.org, dm-devel@...hat.com,
	Neil Brown <neilb@...e.de>
Subject: [PATCH 1/2 block#for-linus] bio, fs: update READA and SWRITE to match
 the corresponding BIO_RW_* bits

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 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 READA and SWRITE.

This patch updates 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.

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@...nel.org>
Reported-and-bisected-by: Vladislav Bolkhovitin <vst@...b.net>
Root-caused-by: Neil Brown <neilb@...e.de>
Cc: Jens Axobe <axboe@...nel.dk>
Cc: stable@...nel.org
---
Aieee... thanks for root causing it Neil.  That was a stupid bug.  I
knew that READ/WRITE were hardcoded but forgot about READA.  :-(
Moving BIO_RW_AHEAD back to bit 1 might be a better solution but I'm
afraid that would cause more confusions downstream.  This patch
updates READA and SWRITE to match BIO_RW_AHEAD and should also appear
in -stable releases.  The next patch will create bio_types.h and
define all constants in terms of BIO_RW_*.

Thanks.

 include/linux/fs.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: work/include/linux/fs.h
===================================================================
--- work.orig/include/linux/fs.h
+++ work/include/linux/fs.h
@@ -148,8 +148,8 @@ struct inodes_stat_t {
 #define RWA_MASK	2
 #define READ 0
 #define WRITE 1
-#define READA 2		/* read-ahead  - don't block if no resources */
-#define SWRITE 3	/* for ll_rw_block() - wait for buffer lock */
+#define READA 16	/* read-ahead  - don't block if no resources */
+#define SWRITE 17	/* for ll_rw_block() - wait for buffer lock */
 #define READ_SYNC	(READ | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG))
 #define READ_META	(READ | (1 << BIO_RW_META))
 #define WRITE_SYNC_PLUG	(WRITE | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_NOIDLE))
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/