Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758072AbZDWHj0 (ORCPT ); Thu, 23 Apr 2009 03:39:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756218AbZDWHaI (ORCPT ); Thu, 23 Apr 2009 03:30:08 -0400 Received: from sous-sol.org ([216.99.217.87]:48619 "EHLO x200.localdomain" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756285AbZDWHaE (ORCPT ); Thu, 23 Apr 2009 03:30:04 -0400 Message-Id: <20090423072437.524221582@sous-sol.org> User-Agent: quilt/0.47-1 Date: Thu, 23 Apr 2009 00:20:54 -0700 From: Chris Wright To: linux-kernel@vger.kernel.org, stable@kernel.org, jejb@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , Willy Tarreau , Rodrigo Rubira Branco , Jake Edge , Eugene Teo , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Mikulas Patocka , Alasdair G Kergon Subject: [patch 034/100] dm: preserve bi_io_vec when resubmitting bios References: <20090423072020.428683652@sous-sol.org> Content-Disposition: inline; filename=dm-preserve-bi_io_vec-when-resubmitting-bios.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2650 Lines: 91 -stable review patch. If anyone has any objections, please let us know. --------------------- From: Mikulas Patocka upstream commit: a920f6b3accc77d9dddbc98a7426be23ee479625 Device mapper saves and restores various fields in the bio, but it doesn't save bi_io_vec. If the device driver modifies this after a partially successful request, dm-raid1 and dm-multipath may attempt to resubmit a bio that has bi_size inconsistent with the size of vector. To make requests resubmittable in dm-raid1 and dm-multipath, we must save and restore the bio vector as well. To reduce the memory overhead involved in this, we do not save the pages in a vector and use a 16-bit field size if the page size is less than 65536. Cc: stable@kernel.org Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon Signed-off-by: Chris Wright --- drivers/md/dm-bio-record.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) --- a/drivers/md/dm-bio-record.h +++ b/drivers/md/dm-bio-record.h @@ -16,30 +16,56 @@ * functions in this file help the target record and restore the * original bio state. */ + +struct dm_bio_vec_details { +#if PAGE_SIZE < 65536 + __u16 bv_len; + __u16 bv_offset; +#else + unsigned bv_len; + unsigned bv_offset; +#endif +}; + struct dm_bio_details { sector_t bi_sector; struct block_device *bi_bdev; unsigned int bi_size; unsigned short bi_idx; unsigned long bi_flags; + struct dm_bio_vec_details bi_io_vec[BIO_MAX_PAGES]; }; static inline void dm_bio_record(struct dm_bio_details *bd, struct bio *bio) { + unsigned i; + bd->bi_sector = bio->bi_sector; bd->bi_bdev = bio->bi_bdev; bd->bi_size = bio->bi_size; bd->bi_idx = bio->bi_idx; bd->bi_flags = bio->bi_flags; + + for (i = 0; i < bio->bi_vcnt; i++) { + bd->bi_io_vec[i].bv_len = bio->bi_io_vec[i].bv_len; + bd->bi_io_vec[i].bv_offset = bio->bi_io_vec[i].bv_offset; + } } static inline void dm_bio_restore(struct dm_bio_details *bd, struct bio *bio) { + unsigned i; + bio->bi_sector = bd->bi_sector; bio->bi_bdev = bd->bi_bdev; bio->bi_size = bd->bi_size; bio->bi_idx = bd->bi_idx; bio->bi_flags = bd->bi_flags; + + for (i = 0; i < bio->bi_vcnt; i++) { + bio->bi_io_vec[i].bv_len = bd->bi_io_vec[i].bv_len; + bio->bi_io_vec[i].bv_offset = bd->bi_io_vec[i].bv_offset; + } } #endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/