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  1. 16 6月, 2009 1 次提交
  3. 09 4月, 2009 1 次提交
  5. 17 3月, 2009 2 次提交
  7. 06 1月, 2009 2 次提交
    • M
      dm table: rework reference counting · d5816876
      由 Mikulas Patocka 提交于 
      Rework table reference counting.

The existing code uses a reference counter. When the last reference is
dropped and the counter reaches zero, the table destructor is called.
Table reference counters are acquired/released from upcalls from other
kernel code (dm_any_congested, dm_merge_bvec, dm_unplug_all).
If the reference counter reaches zero in one of the upcalls, the table
destructor is called from almost random kernel code.

This leads to various problems:
* dm_any_congested being called under a spinlock, which calls the
  destructor, which calls some sleeping function.
* the destructor attempting to take a lock that is already taken by the
  same process.
* stale reference from some other kernel code keeps the table
  constructed, which keeps some devices open, even after successful
  return from "dmsetup remove". This can confuse lvm and prevent closing
  of underlying devices or reusing device minor numbers.

The patch changes reference counting so that the table destructor can be
called only at predetermined places.

The table has always exactly one reference from either mapped_device->map
or hash_cell->new_map. After this patch, this reference is not counted
in table->holders.  A pair of dm_create_table/dm_destroy_table functions
is used for table creation/destruction.

Temporary references from the other code increase table->holders. A pair
of dm_table_get/dm_table_put functions is used to manipulate it.

When the table is about to be destroyed, we wait for table->holders to
reach 0. Then, we call the table destructor.  We use active waiting with
msleep(1), because the situation happens rarely (to one user in 5 years)
and removing the device isn't performance-critical task: the user doesn't
care if it takes one tick more or not.

This way, the destructor is called only at specific points
(dm_table_destroy function) and the above problems associated with lazy
destruction can't happen.

Finally remove the temporary protection added to dm_any_congested().
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      d5816876
    • M
      dm ioctl: allow dm_copy_name_and_uuid to return only one field · 23d39f63
      由 Milan Broz 提交于 
      Allow NULL buffer in dm_copy_name_and_uuid if you only want to return one of
the fields.

(Required by a following patch that adds these fields to sysfs.)
Signed-off-by: NMilan Broz <mbroz@redhat.com>
Reviewed-by: NAlasdair G Kergon <agk@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      23d39f63
  9. 21 10月, 2008 1 次提交
  11. 10 10月, 2008 1 次提交
  13. 09 10月, 2008 2 次提交
    • T
      block: move policy from disk to part0 · b7db9956
      由 Tejun Heo 提交于 
      Move disk->policy to part0->policy.  Implement and use get_disk_ro().
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      b7db9956
    • T
      block: don't depend on consecutive minor space · f331c029
      由 Tejun Heo 提交于 
      * Implement disk_devt() and part_devt() and use them to directly
  access devt instead of computing it from ->major and ->first_minor.

  Note that all references to ->major and ->first_minor outside of
  block layer is used to determine devt of the disk (the part0) and as
  ->major and ->first_minor will continue to represent devt for the
  disk, converting these users aren't strictly necessary.  However,
  convert them for consistency.

* Implement disk_max_parts() to avoid directly deferencing
  genhd->minors.

* Update bdget_disk() such that it doesn't assume consecutive minor
  space.

* Move devt computation from register_disk() to add_disk() and make it
  the only one (all other usages use the initially determined value).

These changes clean up the code and will help disk->part dereference
fix and extended block device numbers.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      f331c029
  15. 08 2月, 2008 3 次提交
  17. 21 12月, 2007 2 次提交
    • A
      dm: trigger change uevent on rename · 69267a30
      由 Alasdair G Kergon 提交于 
      Insert a missing KOBJ_CHANGE notification when a device is renamed.

Cc: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      69267a30
    • J
      dm: table detect io beyond device · 512875bd
      由 Jun'ichi Nomura 提交于 
      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:
      512875bd
  19. 20 10月, 2007 3 次提交
    • M
      dm: export name and uuid · 96a1f7db
      由 Mike Anderson 提交于 
      This patch adds a function to obtain a copy of a mapped device's name and uuid.
Signed-off-by: NMike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      96a1f7db
    • J
      dm io:ctl remove vmalloc void cast · bb56acf8
      由 Jesper Juhl 提交于 
      In drivers/md/dm-ioctl.c::copy_params() there's a call to vmalloc()
where we currently cast the return value, but that's pretty pointless
given that vmalloc() returns "void *".
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      bb56acf8
    • M
      dm io:ctl use constant struct size · 027d50f9
      由 Milan Broz 提交于 
      Make size of dm_ioctl struct always 312 bytes on all supported
architectures.

This change retains compatibility with already-compiled code because
it uses an embedded offset to locate the payload that follows the
structure.

On 64-bit architectures there is no change at all; on 32-bit
we are increasing the size of dm-ioctl from 308 to 312 bytes.

Currently with 32-bit userspace / 64-bit kernel on x86_64
some ioctls (including rename, message) are incorrectly rejected
by the comparison against 'param + 1'.  This breaks userspace
lvrename and multipath 'fail_if_no_path' changes, for example.

(BTW Device-mapper uses its own versioning and ignores the ioctl
size bits.  Only the generic ioctl compat code on mixed arches
checks them, and that will continue to accept both sizes for now,
but we intend to list 308 as deprecated and eventually remove it.)
Signed-off-by: NMilan Broz <mbroz@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Cc: Guido Guenther <agx@sigxcpu.org>
Cc: Kevin Corry <kevcorry@us.ibm.com>
Cc: stable@kernel.org
      027d50f9
  21. 13 2月, 2007 1 次提交
  23. 09 12月, 2006 2 次提交
  25. 09 11月, 2006 1 次提交
    • A
      [PATCH] dm: fix find_device race · bfc5ecdf
      由 Alasdair G Kergon 提交于 
      There is a race between dev_create() and find_device().

If the mdptr has not yet been stored against a device, find_device() needs to
behave as though no device was found.  It already returns NULL, but there is a
dm_put() missing: it must drop the reference dm_get_md() took.

The bug was introduced by dm-fix-mapped-device-ref-counting.patch.

It manifests itself if another dm ioctl attempts to reference a newly-created
device while the device creation ioctl is still running.  The consequence is
that the device cannot be removed until the machine is rebooted.  Certain udev
configurations can lead to this happening.
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Cc: <dm-devel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      bfc5ecdf
  27. 27 6月, 2006 9 次提交
  29. 28 3月, 2006 3 次提交
  31. 02 2月, 2006 1 次提交
  33. 15 1月, 2006 1 次提交
  35. 07 1月, 2006 3 次提交
  37. 23 11月, 2005 1 次提交
    • A
      [PATCH] device-mapper: list_versions fix · c4cc6635
      由 Alasdair G Kergon 提交于 
      In some circumstances the LIST_VERSIONS output is truncated because the size
calculation forgets about a 'uint32_t' in each structure - but the inclusion
of the whole of ALIGN_MASK frequently compensates for the omission.

This is a quick workaround to use an upper bound.  (The code ought to be fixed
to supply the actual size.)

Running 'dmsetup targets' may demonstrate the problem: when I run it, the last
line comes out as 'erro' instead of 'error'.  Consequently, 'lvcreate --type
error' doesn't work.
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      c4cc6635