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MD RAID5: Avoid accessing gendisk or queue structs when not available

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MD RAID5:  Fix kernel oops when RAID4/5/6 is used via device-mapper

Commit a9add5d (v3.8-rc1) added blktrace calls to the RAID4/5/6 driver.
However, when device-mapper is used to create RAID4/5/6 arrays, the
mddev->gendisk and mddev->queue fields are not setup.  Therefore, calling
things like trace_block_bio_remap will cause a kernel oops.  This patch
conditionalizes those calls on whether the proper fields exist to make
the calls.  (Device-mapper will call trace_block_bio_remap on its own.)

This patch is suitable for the 3.8.y stable kernel.

Cc: stable@vger.kernel.org (v3.8+)
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
Jonathan Brassow 2013-03-07 16:22:01 -06:00 committed by NeilBrown
parent ce7d363aaf
commit e3620a3ad5
1 changed files with 20 additions and 13 deletions
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33
drivers/md/raid5.c
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@ -674,9 +674,11 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
bi->bi_next = NULL;
if (rrdev)
set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
bi, disk_devt(conf->mddev->gendisk),
sh->dev[i].sector);
if (conf->mddev->gendisk)
trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
bi, disk_devt(conf->mddev->gendisk),
sh->dev[i].sector);
generic_make_request(bi);
}
if (rrdev) {
@ -704,9 +706,10 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
rbi->bi_io_vec[0].bv_offset = 0;
rbi->bi_size = STRIPE_SIZE;
rbi->bi_next = NULL;
trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
rbi, disk_devt(conf->mddev->gendisk),
sh->dev[i].sector);
if (conf->mddev->gendisk)
trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
rbi, disk_devt(conf->mddev->gendisk),
sh->dev[i].sector);
generic_make_request(rbi);
}
if (!rdev && !rrdev) {
@ -2835,8 +2838,10 @@ static void handle_stripe_dirtying(struct r5conf *conf,
set_bit(STRIPE_HANDLE, &sh->state);
if (rmw < rcw && rmw > 0) {
/* prefer read-modify-write, but need to get some data */
blk_add_trace_msg(conf->mddev->queue, "raid5 rmw %llu %d",
(unsigned long long)sh->sector, rmw);
if (conf->mddev->queue)
blk_add_trace_msg(conf->mddev->queue,
"raid5 rmw %llu %d",
(unsigned long long)sh->sector, rmw);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if ((dev->towrite || i == sh->pd_idx) &&
@ -2886,7 +2891,7 @@ static void handle_stripe_dirtying(struct r5conf *conf,
}
}
}
if (rcw)
if (rcw && conf->mddev->queue)
blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
(unsigned long long)sh->sector,
rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
@ -3993,9 +3998,10 @@ static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
atomic_inc(&conf->active_aligned_reads);
spin_unlock_irq(&conf->device_lock);
trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev),
align_bi, disk_devt(mddev->gendisk),
raid_bio->bi_sector);
if (mddev->gendisk)
trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev),
align_bi, disk_devt(mddev->gendisk),
raid_bio->bi_sector);
generic_make_request(align_bi);
return 1;
} else {
@ -4089,7 +4095,8 @@ static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
}
spin_unlock_irq(&conf->device_lock);
}
trace_block_unplug(mddev->queue, cnt, !from_schedule);
if (mddev->queue)
trace_block_unplug(mddev->queue, cnt, !from_schedule);
kfree(cb);
}