Enable discard support in the DM multipath target.
This discard support depends on a few discard-specific fixes to the
block layer's request stacking driver methods.
Discard requests are optional so don't allow a failed discard to trigger
path failures. If there is a real problem with a given path the
barriers associated with the discard (either before or after the
discard) will cause path failure. That said, unconditionally passing
discard failures up the stack is not ideal. This must be fixed once DM
has more information about the nature of the underlying storage failure.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
multipath_ctr() forgets to return an error after detecting
missing path parameters. Fix this.
Signed-off-by: Patrick LoPresti <lopresti@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Remove unused parameters(start and len) of dm_get_device()
and fix the callers.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch pulls the pg_init path activation code out of
process_queued_ios() into a new function.
No functional change.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
When suspending the device we must wait for all I/O to complete, but
pg-init may be still in progress even after flushing the workqueue
for kmpath_handlerd in multipath_postsuspend.
This patch waits for pg-init completion correctly in
multipath_postsuspend().
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
m->queue_io is set to block processing I/Os, and it needs to be kept
while pg-init, which issues multiple path activations, is in progress.
But m->queue is cleared when a path activation completes without error
in pg_init_done(), even while other path activations are in progress.
That may cause undesired -EIO on paths which are not complete activation.
This patch fixes that by not clearing m->queue_io until all path
activations complete.
(Before the hardware handlers were moved into the SCSI layer, pg_init
only used one path.)
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
'suspended' flag in struct multipath was introduced to check whether
the multipath target is in suspended state, but the same check is
done through dm_suspended() now, so remove the flag and related code.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch adds two minor fixes while processing device mapper path activation.
Skip failed paths while calling activate_path. If the path is already failed
then activate_path will fail for sure. We don't have to call in that case. In
some case this might cause prolonged retries unnecessarily.
Change the misleading message if the path being activated fails with SCSI_DH_NOSYS.
Signed-off-by: Babu Moger <babu.moger@lsi.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch removes some unnecessary argument casting. There is no
functional change with this patch.
Passes 'struct pgpath' through to pg_init_done() instead of the enclosed
'struct dm_path'.
Tested the changes with LSI storage..
CC: Chandra Seetharaman <chandra.seetharaman@us.ibm.com>
Signed-off-by: Babu Moger <babu.moger@lsi.com>
Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch rejects messages that can generate I/O while the device
itself is suspended.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Cc: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Reject messages that can generate I/O while the device itself
is suspended.
Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Add a mutex to allow possible creators of new work to synchronize with
flushing work queues.
Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch stops the remaining dm-mpath activity during the suspend
sequence by flushing workqueues in postsuspend function.
The current dm-mpath target may not be quiet even after suspend completes
because some workqueues (e.g. device_handler's work, event handling)
are not flushed during the suspend sequence, even though suspended
devices/targets are supposed to be quiet in this state.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Make scsi_dh_activate() function asynchronous, by taking in two additional
parameters, one is the callback function and the other is the data to call
the callback function with.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Use scsi_dh_set_params() set parameters provided. Save the parameters in
parse_hw_handler() and use it in parse_path().
Reported-by: Eddie Williams <Eddie.Williams@steeleye.com>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Tested-by: Eddie Williams <Eddie.Williams@steeleye.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Incorrect device area lengths are being passed to device_area_is_valid().
The regression appeared in 2.6.31-rc1 through commit
754c5fc7eb.
With the dm-stripe target, the size of the target (ti->len) was used
instead of the stripe_width (ti->len/#stripes). An example of a
consequent incorrect error message is:
device-mapper: table: 254:0: sdb too small for target
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: martin.petersen@oracle.com
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: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The commit fe9cf30eb8 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: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: stable@kernel.org
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: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
When specifying a different hardware handler via multipath
features we should be able to override the built-in defaults.
The problem here is the hardware table from scsi_dh is compiled
in and cannot be changed from userland. The multipath.conf OTOH
is purely user-defined and, what's more, the user might have a valid
reason for modifying it.
(EG EMC Clariion can well be run in PNR mode even though ALUA is
active, or the user might want to try ALUA on any as-of-yet unknown
devices)
So _not_ allowing multipath to override the device handler setting
will just add to the confusion and makes error tracking even more
difficult.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
It's used by DM and MD and generally useful, so move the bio list
helpers into bio.h.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
The same workqueue is used both for sending uevents and processing queued I/O.
Deadlock has been reported in RHEL5 when sending a uevent was blocked waiting
for the queued I/O to be processed. Use scheduled_work() for the asynchronous
uevents instead.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Change dm_unregister_target to return void and use BUG() for error
reporting.
dm_unregister_target can only fail because of programming bug in the
target driver. It can't fail because of user's behavior or disk errors.
This patch changes unregister_target to return void and use BUG if
someone tries to unregister non-registered target or unregister target
that is in use.
This patch removes code duplication (testing of error codes in all dm
targets) and reports bugs in just one place, in dm_unregister_target. In
some target drivers, these return codes were ignored, which could lead
to a situation where bugs could be missed.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Currently dm ignores the parameters provided to hardware handlers
without providing any notifications to the user.
This patch just prints a warning message so that the user knows that
the arguments are ignored.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Path activation code is called even when the pgpath is NULL. This could
lead to a panic in activate_path(). Such a panic is seen in -rt kernel.
This problem has been there before the pg_init() was moved to a
workqueue.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Change #include "dm.h" to #include <linux/device-mapper.h> in all targets.
Targets should not need direct access to internal DM structures.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Analog of blkdev_driver_ioctl() with sane arguments. For
now uses fake struct file, by the end of the series it won't
and blkdev_driver_ioctl() will become a wrapper around it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Multipath is best at handling transport errors. If it gets a device
error then there is not much the multipath layer can do. It will just
access the same device but from a different path.
This patch breaks up failfast into device, transport and driver errors.
The multipath layers (md and dm mutlipath) only ask the lower levels to
fast fail transport errors. The user of failfast, read ahead, will ask
to fast fail on all errors.
Note that blk_noretry_request will return true if any failfast bit
is set. This allows drivers that do not support the multipath failfast
bits to continue to fail on any failfast error like before. Drivers
like scsi that are able to fail fast specific errors can check
for the specific fail fast type. In the next patch I will convert
scsi.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This patch moves 'is_active' from struct dm_path to struct pgpath
as it does not need exporting.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch allows path errors from the multipath ctr function to
propagate up to userspace as errno values from the ioctl() call.
This is in response to
https://www.redhat.com/archives/dm-devel/2008-May/msg00000.html
and
https://bugzilla.redhat.com/show_bug.cgi?id=444421
The patch only lets through the errors that it needs to in order to
get the path errors from parse_path().
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Moving the path activation to workqueue along with scsi_dh patches introduced
a race. It is due to the fact that the current_pgpath (in the multipath data
structure) can be modified if changes happen in any of the paths leading to
the lun. If the changes lead to current_pgpath being set to NULL, then it
leads to the invalid access which results in the panic below.
This patch fixes that by storing the pgpath to activate in the multipath data
structure and properly protecting it.
Note that if activate_path is called twice in succession with different pgpath,
with the second one being called before the first one is done, then activate
path will be called twice for the second pgpath, which is fine.
Unable to handle kernel paging request for data at address 0x00000020
Faulting instruction address: 0xd000000000aa1844
cpu 0x1: Vector: 300 (Data Access) at [c00000006b987a80]
pc: d000000000aa1844: .activate_path+0x30/0x218 [dm_multipath]
lr: c000000000087a2c: .run_workqueue+0x114/0x204
sp: c00000006b987d00
msr: 8000000000009032
dar: 20
dsisr: 40000000
current = 0xc0000000676bb3f0
paca = 0xc0000000006f3680
pid = 2528, comm = kmpath_handlerd
enter ? for help
[c00000006b987da0] c000000000087a2c .run_workqueue+0x114/0x204
[c00000006b987e40] c000000000088b58 .worker_thread+0x120/0x144
[c00000006b987f00] c00000000008ca70 .kthread+0x78/0xc4
[c00000006b987f90] c000000000027cc8 .kernel_thread+0x4c/0x68
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
multipath keeps a separate device table which may be
more current than the built-in one.
So we should make sure to always call ->attach whenever
a multipath map with hardware handler is instantiated.
And we should call ->detach on removal, too.
[sekharan: update as per comments from agk]
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Return a specific error message if there are an invalid number of multipath
arguments.
This invalid command returns an "Unknown error" because the ti->error field is
not set
dmsetup create --table '0 2 multipath 0 0 1 1 round-robin 0 1 1 /dev/sdh' mpath0
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Free path selector if the arguments are invalid.
This command (note that it is invalid) causes reference leak on module
"dm_round_robin" and prevents the module from being removed.
dmsetup create --table '0 2 multipath 0 0 1 1 round-robin /dev/sdh' mpath0
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Do not automatically "select" SCSI_DH for dm-multipath. If SCSI_DH
doesn't exist,just do not allow hardware handlers to be used.
Handle SCSI_DH being a module also. Make sure it doesn't allow DM_MULTIPATH
to be compiled in when SCSI_DH is a module.
[jejb: added comment for Kconfig syntax]
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This patch just removes the dm layer's path initialization completion
routine. This is separated from the other patch(scsi_dh: Use SCSI
device handler in dm-multipath) Just to make that patch more readable.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Before this patch set (SCSI hardware handlers), initialization of a
path was done asynchronously. Doing that requires a workqueue in each
device/hardware handler module and leads to unneccessary complication
in the device handler code, making it difficult to read the code and
follow the state diagram.
Moving that workqueue to this level makes the device handler code simpler.
Hence, the workqueue is moved to dm level.
A new workqueue is added instead of adding it to the existing workqueue
(kmpathd) for the following reasons:
1. Device activation has to happen faster, stacking them along
with the other workqueue might lead to unnecessary delay
in the activation of the path.
2. The effect could be felt the other way too. i.e the current
events that are handled by the existing workqueue might get
a delayed response.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This patch converts dm-mpath to use scsi device handlers instead of
dm's hardware handlers.
This patch does not add any new functionality. Old behaviors remain and
userspace tools work as is except that arguments supplied with hardware
handler are ignored.
One behavioral exception is: Activation of a path is synchronous in this
patch, opposed to the older behavior of being asynchronous (changed in
patch 07: scsi_dh: Add a single threaded workqueue for initializing a path)
Note: There is no need to get a reference for the device handler module
(as it was done in the dm hardware handler case) here as the reference
is held when the device was first found. Instead we check and make sure
that support for the specified device is present at table load time.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This patch adds calls to dm_path_event for a failed path and a reinstated
path.
Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch allows a failed path group initialisation command to be retried.
It adds a generic MP_RETRY flag and a "pg_init_retries" feature to
device-mapper multipath which limits the number of retries.
1. A hw handler sends a path initialization command to the storage and
the command completes with an error code indicating the command
should be retried.
2. The hardware handler calls dm_pg_init_complete() with MP_RETRY
set in err_flags to ask the dm multipath core to retry.
3. If the retry limit has not been exceeded, pg_init() is retried.
Otherwise fail_path() is called.
If you are using the userspace multipath-tools or device-mapper-multipath
package, you can set pg_init_retries in the 'device' section of your
/etc/multipath.conf file. For example:
features "2 pg_init_retries 7"
The number of PG retries attempted is reported in the 'dmsetup status' output.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Acked-by: Mike Christie <michaelc@cs.wisc.edu>
Acked-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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 <neilb@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Mike Snitzer