Skip to content

K
kernel_linux

OpenHarmony / kernel_linux
上一次同步 3 年多

通知 13
Star 8
Fork 2
K
kernel_linux
切换分支/标签
  1. 03 6月, 2012 3 次提交
    • M
      dm mpath: allow ioctls to trigger pg init · 35991652
      由 Mikulas Patocka 提交于 
      After the failure of a group of paths, any alternative paths that
need initialising do not become available until further I/O is sent to
the device.  Until this has happened, ioctls return -EAGAIN.

With this patch, new paths are made available in response to an ioctl
too.  The processing of the ioctl gets delayed until this has happened.

Instead of returning an error, we submit a work item to kmultipathd
(that will potentially activate the new path) and retry in ten
milliseconds.

Note that the patch doesn't retry an ioctl if the ioctl itself fails due
to a path failure.  Such retries should be handled intelligently by the
code that generated the ioctl in the first place, noting that some SCSI
commands should not be retried because they are not idempotent (XOR write
commands).  For commands that could be retried, there is a danger that
if the device rejected the SCSI command, the path could be errorneously
marked as failed, and the request would be retried on another path which
might fail too.  It can be determined if the failure happens on the
device or on the SCSI controller, but there is no guarantee that all
SCSI drivers set these flags correctly.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      35991652
    • M
      dm mpath: delay retry of bypassed pg · f220fd4e
      由 Mike Christie 提交于 
      If I/O needs retrying and only bypassed priority groups are available,
set the pg_init_delay_retry flag to wait before retrying.

If, for example, the reason for the bypass is that the controller is
getting reset or there is a firmware upgrade happening, retrying right
away would cause a flood of log messages and retries for what could be a
few seconds or even several minutes.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Acked-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      f220fd4e
    • M
      dm mpath: reduce size of struct multipath · 1fbdd2b3
      由 Mike Snitzer 提交于 
      Move multipath structure's 'lock' and 'queue_size' members to eliminate
two 4-byte holes.  Also use a bit within a single unsigned int for each
existing flag (saves 8-bytes).  This allows future flags to be added
without each consuming an unsigned int.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Acked-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      1fbdd2b3
  3. 12 5月, 2012 1 次提交
  5. 29 3月, 2012 2 次提交
  7. 15 1月, 2012 1 次提交
  9. 02 8月, 2011 2 次提交
  11. 27 7月, 2011 1 次提交
  13. 29 5月, 2011 1 次提交
  15. 24 3月, 2011 2 次提交
    • M
      dm mpath: allow table load with no priority groups · a490a07a
      由 Mike Snitzer 提交于 
      This patch adjusts the multipath target to allow a table with both 0
priority groups and 0 for the initial priority group number.

If any mpath device is held open when all paths in the last priority
group have failed, userspace multipathd will attempt to reload the
associated DM table to reflect the fact that the device no longer has
any priority groups.  But the reload attempt always failed because the
multipath target did not allow 0 priority groups.

All multipath target messages related to priority group (enable_group,
disable_group, switch_group) will handle a priority group of 0 (will
cause error).

When reloading a multipath table with 0 priority groups, userspace
multipathd must be updated to specify an initial priority group number
of 0 (rather than 1).
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Cc: Babu Moger <babu.moger@lsi.com>
Acked-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      a490a07a
    • M
      dm mpath: fail message ioctl if specified path is not valid · 19040c0b
      由 Mike Snitzer 提交于 
      Fail the reinstate_path and fail_path message ioctl if the specified
path is not valid.

The message ioctl would succeed for the 'reinistate_path' and
'fail_path' messages even if action was not taken because the
specified device was not a valid path of the multipath device.

Before, when /dev/vdb is not a path of mpathb:
$ dmsetup message mpathb 0 reinstate_path /dev/vdb
$ echo $?
0

After:
$ dmsetup message mpathb 0 reinstate_path /dev/vdb
device-mapper: message ioctl failed: Invalid argument
Command failed
$ echo $?
1
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      19040c0b
  17. 13 2月, 2011 1 次提交
  19. 14 1月, 2011 4 次提交
  21. 12 8月, 2010 2 次提交
  23. 06 3月, 2010 7 次提交
  25. 11 12月, 2009 4 次提交
  27. 05 12月, 2009 1 次提交
  29. 23 8月, 2009 1 次提交
  31. 24 7月, 2009 1 次提交
  33. 22 6月, 2009 6 次提交
    • K
      dm mpath: change to be request based · f40c67f0
      由 Kiyoshi Ueda 提交于 
      This patch converts dm-multipath target to request-based from bio-based.

Basically, the patch just converts the I/O unit from struct bio
to struct request.
In the course of the conversion, it also changes the I/O queueing
mechanism.  The change in the I/O queueing is described in details
as follows.

I/O queueing mechanism change
-----------------------------
In I/O submission, map_io(), there is no mechanism change from
bio-based, since the clone request is ready for retry as it is.
However, in I/O complition, do_end_io(), there is a mechanism change
from bio-based, since the clone request is not ready for retry.

In do_end_io() of bio-based, the clone bio has all needed memory
for resubmission.  So the target driver can queue it and resubmit
it later without memory allocations.
The mechanism has almost no overhead.

On the other hand, in do_end_io() of request-based, the clone request
doesn't have clone bios, so the target driver can't resubmit it
as it is.  To resubmit the clone request, memory allocation for
clone bios is needed, and it takes some overheads.
To avoid the overheads just for queueing, the target driver doesn't
queue the clone request inside itself.
Instead, the target driver asks dm core for queueing and remapping
the original request of the clone request, since the overhead for
queueing is just a freeing memory for the clone request.

As a result, the target driver doesn't need to record/restore
the information of the original request for resubmitting
the clone request.  So dm_bio_details in dm_mpath_io is removed.

multipath_busy()
---------------------
The target driver returns "busy", only when the following case:
  o The target driver will map I/Os, if map() function is called
  and
  o The mapped I/Os will wait on underlying device's queue due to
    their congestions, if map() function is called now.

In other cases, the target driver doesn't return "busy".
Otherwise, dm core will keep the I/Os and the target driver can't
do what it wants.
(e.g. the target driver can't map I/Os now, so wants to kill I/Os.)
Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      f40c67f0
    • M
      dm target:s introduce iterate devices fn · af4874e0
      由 Mike Snitzer 提交于 
      Add .iterate_devices to 'struct target_type' to allow a function to be
called for all devices in a DM target.  Implemented it for all targets
except those in dm-snap.c (origin and snapshot).

(The raid1 version number jumps to 1.12 because we originally reserved
1.1 to 1.11 for 'block_on_error' but ended up using 'handle_errors'
instead.)
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Cc: martin.petersen@oracle.com
      af4874e0
    • K
      dm mpath: add start_io and nr_bytes to path selectors · 02ab823f
      由 Kiyoshi Ueda 提交于 
      This patch makes two additions to the dm path selector interface for
dynamic load balancers:
  o a new hook, start_io()
  o a new parameter 'nr_bytes' to select_path()/start_io()/end_io()
    to pass the size of the I/O

start_io() is called when a target driver actually submits I/O
to the selected path.
Path selectors can use it to start accounting of the I/O.
(e.g. counting the number of in-flight I/Os.)
The start_io hook is based on the patch posted by Stefan Bader:
https://www.redhat.com/archives/dm-devel/2005-October/msg00050.html

nr_bytes, the size of the I/O, is so path selectors can take the
size of the I/O into account when deciding which path to use.
dm-service-time uses it to estimate service time, for example.
(Added the nr_bytes member to dm_mpath_io instead of using existing
 details.bi_size, since request-based dm patch deletes it.)
Signed-off-by: NStefan Bader <stefan.bader@canonical.com>
Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      02ab823f
    • M
      dm mpath: support barriers · 8627921f
      由 Mikulas Patocka 提交于 
      Flush support for dm-multipath target.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      8627921f
    • M
      dm mpath: flush keventd queue in destructor · 53b351f9
      由 Mikulas Patocka 提交于 
      The commit fe9cf30e moves dm table event
submission from kmultipath queue to kernel kevent queue to avoid a
deadlock.

There is a possibility of race condition because kevent queue is not flushed
in the multipath destructor. The scenario is:
- some event happens and is queued to keventd
- keventd thread is delayed due to scheuling latency or some other work
- multipath device is destroyed
- keventd now attempts to process work_struct that is residing in already
  released memory.

The patch flushes the keventd queue in multipath constructor.
I've already fixed similar bug in dm-raid1.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Cc: stable@kernel.org
      53b351f9
    • C
      dm mpath: call activate fn for each path in pg_init · e54f77dd
      由 Chandra Seetharaman 提交于 
      Fixed a problem affecting reinstatement of passive paths.

Before we moved the hardware handler from dm to SCSI, it performed a pg_init
for a path group and didn't maintain any state about each path in hardware
handler code.

But in SCSI dh, such state is now maintained, as we want to fail I/O early on a
path if it is not the active path.

All the hardware handlers have a state now and set to active or some form of
inactive.  They have prep_fn() which uses this state to fail the I/O without
it ever being sent to the device.

So in effect when dm-multipath calls scsi_dh_activate(), activate is
sent to only one path and the "state" of that path is changed appropriately
to "active" while other paths in the same path group are never changed
as they never got an "activate".

In order make sure all the paths in a path group gets their state set
properly when a pg_init happens, we need to call scsi_dh_activate() on
all paths in a path group.

Doing this at the hardware handler layer is not a good option as we
want the multipath layer to define the relationship between path and path
groups and not the hardware handler.

Attached patch sends an "activate" on each path in a path group when a
path group is switched. It also sends an activate when a path is reinstated.
Signed-off-by: NChandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      e54f77dd