kernel.git/drivers/md/dm.c, branch linux-2.6.23.y

dm: table detect io beyond device

2008-02-08T20:01:07Z

Patch 512875bd9661368da6f993205a61213b79ba1df0 in mainline. This patch fixes a panic on shrinking a DM device if there is outstanding I/O to the part of the device that is being removed. (Normally this doesn't happen - a filesystem would be resized first, for example.) The bug is that __clone_and_map() assumes dm_table_find_target() always returns a valid pointer. It may fail if a bio arrives from the block layer but its target sector is no longer included in the DM btree. This patch appends an empty entry to table->targets[] which will be returned by a lookup beyond the end of the device. After calling dm_table_find_target(), __clone_and_map() and target_message() check for this condition using dm_target_is_valid(). Sample test script to trigger oops: #!/bin/bash FILE=$(mktemp) LODEV=$(losetup -f) MAP=$(basename ${FILE}) SIZE=4M dd if=/dev/zero of=${FILE} bs=${SIZE} count=1 losetup ${LODEV} ${FILE} echo "0 $(blockdev --getsz ${LODEV}) linear ${LODEV} 0" |dmsetup create ${MAP} dmsetup suspend ${MAP} echo "0 1 linear ${LODEV} 0" |dmsetup load ${MAP} dd if=/dev/zero of=/dev/mapper/${MAP} bs=${SIZE} count=1 & echo "Wait til dd push some I/O" sleep 5 dmsetup resume ${MAP} Signed-off-by: Jun'ichi Nomura Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

dm: fix thaw_bdev

2007-11-16T17:30:21Z

patch ae9da83f6d800fe1f3b23bfbc8f7222ad1c5bb74 in mainline. This patch fixes a bd_mount_sem counter corruption bug in device-mapper. thaw_bdev() should be called only when freeze_bdev() was called for the device. Otherwise, thaw_bdev() will up bd_mount_sem and corrupt the semaphore counter. struct block_device with the corrupted semaphore may remain in slab cache and be reused later. Attached patch will fix it by calling unlock_fs() instead. unlock_fs() will determine whether it should call thaw_bdev() by checking the device is frozen or not. Easy reproducer is: #!/bin/sh while [ 1 ]; do dmsetup --notable create a dmsetup --nolockfs suspend a dmsetup remove a done It's not easy to see the effect of corrupted semaphore. So I have tested with putting printk below in bdev_alloc_inode(): if (atomic_read(&ei->bdev.bd_mount_sem.count) != 1) printk(KERN_DEBUG "Incorrect semaphore count = %d (%p)\n", atomic_read(&ei->bdev.bd_mount_sem.count), &ei->bdev); Without the patch, I saw something like: Incorrect semaphore count = 17 (f2ab91c0) With the patch, the message didn't appear. The bug was introduced in 2.6.16 with this bug fix: commit d9dde59ba03095e526640988c0fedd75e93bc8b7 Date: Fri Feb 24 13:04:24 2006 -0800 [PATCH] dm: missing bdput/thaw_bdev at removal Need to unfreeze and release bdev otherwise the bdev inode with inconsistent state is reused later and cause problem. and backported to 2.6.15.5. It occurs only in free_dev(), which is called only when the dm device is removed. The buggy code is executed only if md->suspended_bdev is non-NULL and that can happen only when the device was suspended without noflush. Signed-off-by: Jun'ichi Nomura Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman

Fix remap handling by blktrace

2007-08-11T20:34:48Z

This patch provides more information concerning REMAP operations on block IOs. The additional information provides clearer details at the user level, and supports post-processing analysis in btt. o Adds in partition remaps on the same device. o Fixed up the remap information in DM to be in the right order o Sent up mapped-from and mapped-to device information Signed-off-by: Alan D. Brunelle Signed-off-by: Jens Axboe

[BLOCK] Get rid of request_queue_t typedef

2007-07-24T07:28:11Z

Some of the code has been gradually transitioned to using the proper struct request_queue, but there's lots left. So do a full sweet of the kernel and get rid of this typedef and replace its uses with the proper type. Signed-off-by: Jens Axboe

unregister_blkdev() delete redundant messages in callers

2007-07-17T17:23:03Z

No need to warn unregister_blkdev() failure by the callers. (The previous patch makes unregister_blkdev() print error message in error case) Signed-off-by: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

dm: disable barriers

2007-07-12T22:01:08Z

This patch causes device-mapper to reject any barrier requests. This is done since most of the targets won't handle this correctly anyway. So until the situation improves it is better to reject these requests at the first place. Since barrier requests won't get to the targets, the checks there can be removed. Cc: stable@kernel.org Signed-off-by: Stefan Bader Signed-off-by: Alasdair G Kergon Signed-off-by: Linus Torvalds

dm: use kmem_cache macro

2007-07-12T22:01:08Z

Use new KMEM_CACHE() macro and make the newly-exposed structure names more meaningful. Also remove some superfluous casts and inlines (let a modern compiler be the judge). Acked-by: Christoph Lameter Signed-off-by: Alasdair G Kergon Signed-off-by: Linus Torvalds

dm mpath: log device name

2007-05-09T19:30:46Z

Make the mapped device structure accessible to hardware handlers so error messages can include the device name. Signed-off-by: Edward Goggin Signed-off-by: Alasdair G Kergon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[BLOCK] Don't pin lots of memory in mempools

2007-04-30T07:08:17Z

Currently we scale the mempool sizes depending on memory installed in the machine, except for the bio pool itself which sits at a fixed 256 entry pre-allocation. There's really no point in "optimizing" this OOM path, we just need enough preallocated to make progress. A single unit is enough, lets scale it down to 2 just to be on the safe side. This patch saves ~150kb of pinned kernel memory on a 32-bit box. Signed-off-by: Jens Axboe

[PATCH] dm-multipath: fix stall on noflush suspend/resume

2007-01-26T21:51:00Z

Allow noflush suspend/resume of device-mapper device only for the case where the device size is unchanged. Otherwise, dm-multipath devices can stall when resumed if noflush was used when suspending them, all paths have failed and queue_if_no_path is set. Explanation: 1. Something is doing fsync() on the block dev, holding inode->i_sem 2. The fsync write is blocked by all-paths-down and queue_if_no_path 3. Someone requests to suspend the dm device with noflush. Pending writes are left in queue. 4. In the middle of dm_resume(), __bind() tries to get inode->i_sem to do __set_size() and waits forever. 'noflush suspend' is a new device-mapper feature introduced in early 2.6.20. So I hope the fix being included before 2.6.20 is released. Example of reproducer: 1. Create a multipath device by dmsetup 2. Fail all paths during mkfs 3. Do dmsetup suspend --noflush and load new map with healthy paths 4. Do dmsetup resume Signed-off-by: Jun'ichi Nomura Acked-by: Alasdair G Kergon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds