linux.git/drivers/md/dm.c, branch v2.6.24

dm: trigger change uevent on rename

2007-12-20T17:32:11+00:00

Insert a missing KOBJ_CHANGE notification when a device is renamed.

Cc: Scott James Remnant 
Signed-off-by: Alasdair G Kergon

dm: table detect io beyond device

2007-12-20T17:32:08+00:00

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:

dm: uevent generate events

2007-10-20T01:01:26+00:00

This patch adds support for the dm_path_event dm_send_event functions which
create and send udev events.

Signed-off-by: Mike Anderson 
Signed-off-by: Alasdair G Kergon

dm: add uevent to core

2007-10-20T01:01:24+00:00

This patch adds a uevent skeleton to device-mapper.

Signed-off-by: Mike Anderson 
Signed-off-by: Alasdair G Kergon

dm: tidy bio_io_error usage

2007-10-20T01:01:09+00:00

Use bio_io_error() in only two places and tidy the code,
preparing for later patches.

There is no functional change in this patch.

Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm: fix thaw_bdev

2007-10-20T01:01:05+00:00

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 
Cc: stable@kernel.org

block: convert blkdev_issue_flush() to use empty barriers

2007-10-16T09:05:02+00:00

Then we can get rid of ->issue_flush_fn() and all the driver private
implementations of that.

Signed-off-by: Jens Axboe

Drop 'size' argument from bio_endio and bi_end_io

2007-10-10T07:25:57+00:00

As bi_end_io is only called once when the reqeust is complete,
the 'size' argument is now redundant.  Remove it.

Now there is no need for bio_endio to subtract the size completed
from bi_size.  So don't do that either.

While we are at it, change bi_end_io to return void.

Signed-off-by: Neil Brown 
Signed-off-by: Jens Axboe

Fix remap handling by blktrace

2007-08-11T20:34:48+00:00

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

2007-07-24T07:28:11+00:00

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