2005-04-16 18:20:36 -04:00
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/*
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* Copyright (C) 2001 Sistina Software (UK) Limited.
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* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the LGPL.
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*/
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#ifndef _LINUX_DEVICE_MAPPER_H
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#define _LINUX_DEVICE_MAPPER_H
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2006-06-26 03:27:33 -04:00
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#ifdef __KERNEL__
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2005-04-16 18:20:36 -04:00
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struct dm_target;
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struct dm_table;
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struct dm_dev;
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2006-06-26 03:27:33 -04:00
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struct mapped_device;
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2005-04-16 18:20:36 -04:00
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typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
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union map_info {
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void *ptr;
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unsigned long long ll;
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};
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/*
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* In the constructor the target parameter will already have the
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* table, type, begin and len fields filled in.
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*/
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typedef int (*dm_ctr_fn) (struct dm_target *target,
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unsigned int argc, char **argv);
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/*
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* The destructor doesn't need to free the dm_target, just
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* anything hidden ti->private.
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*/
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typedef void (*dm_dtr_fn) (struct dm_target *ti);
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/*
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* The map function must return:
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* < 0: error
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* = 0: The target will handle the io by resubmitting it later
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2006-12-08 05:41:05 -05:00
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* = 1: simple remap complete
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[PATCH] dm: suspend: add noflush pushback
In device-mapper I/O is sometimes queued within targets for later processing.
For example the multipath target can be configured to store I/O when no paths
are available instead of returning it -EIO.
This patch allows the device-mapper core to instruct a target to transfer the
contents of any such in-target queue back into the core. This frees up the
resources used by the target so the core can replace that target with an
alternative one and then resend the I/O to it. Without this patch the only
way to change the target in such circumstances involves returning the I/O with
an error back to the filesystem/application. In the multipath case, this
patch will let us add new paths for existing I/O to try after all the existing
paths have failed.
DMF_NOFLUSH_SUSPENDING
----------------------
If the DM_NOFLUSH_FLAG ioctl option is specified at suspend time, the
DMF_NOFLUSH_SUSPENDING flag is set in md->flags during dm_suspend(). It
is always cleared before dm_suspend() returns.
The flag must be visible while the target is flushing pending I/Os so it
is set before presuspend where the flush starts and unset after the wait
for md->pending where the flush ends.
Target drivers can check this flag by calling dm_noflush_suspending().
DM_MAPIO_REQUEUE / DM_ENDIO_REQUEUE
-----------------------------------
A target's map() function can now return DM_MAPIO_REQUEUE to request the
device mapper core queue the bio.
Similarly, a target's end_io() function can return DM_ENDIO_REQUEUE to request
the same. This has been labelled 'pushback'.
The __map_bio() and clone_endio() functions in the core treat these return
values as errors and call dec_pending() to end the I/O.
dec_pending
-----------
dec_pending() saves the pushback request in struct dm_io->error. Once all
the split clones have ended, dec_pending() will put the original bio on
the md->pushback list. Note that this supercedes any I/O errors.
It is possible for the suspend with DM_NOFLUSH_FLAG to be aborted while
in progress (e.g. by user interrupt). dec_pending() checks for this and
returns -EIO if it happened.
pushdback list and pushback_lock
--------------------------------
The bio is queued on md->pushback temporarily in dec_pending(), and after
all pending I/Os return, md->pushback is merged into md->deferred in
dm_suspend() for re-issuing at resume time.
md->pushback_lock protects md->pushback.
The lock should be held with irq disabled because dec_pending() can be
called from interrupt context.
Queueing bios to md->pushback in dec_pending() must be done atomically
with the check for DMF_NOFLUSH_SUSPENDING flag. So md->pushback_lock is
held when checking the flag. Otherwise dec_pending() may queue a bio to
md->pushback after the interrupted dm_suspend() flushes md->pushback.
Then the bio would be left in md->pushback.
Flag setting in dm_suspend() can be done without md->pushback_lock because
the flag is checked only after presuspend and the set value is already
made visible via the target's presuspend function.
The flag can be checked without md->pushback_lock (e.g. the first part of
the dec_pending() or target drivers), because the flag is checked again
with md->pushback_lock held when the bio is really queued to md->pushback
as described above. So even if the flag is cleared after the lockless
checkings, the bio isn't left in md->pushback but returned to applications
with -EIO.
Other notes on the current patch
--------------------------------
- md->pushback is added to the struct mapped_device instead of using
md->deferred directly because md->io_lock which protects md->deferred is
rw_semaphore and can't be used in interrupt context like dec_pending(),
and md->io_lock protects the DMF_BLOCK_IO flag of md->flags too.
- Don't issue lock_fs() in dm_suspend() if the DM_NOFLUSH_FLAG
ioctl option is specified, because I/Os generated by lock_fs() would be
pushed back and never return if there were no valid devices.
- If an error occurs in dm_suspend() after the DMF_NOFLUSH_SUSPENDING
flag is set, md->pushback must be flushed because I/Os may be queued to
the list already. (flush_and_out label in dm_suspend())
Test results
------------
I have tested using multipath target with the next patch.
The following tests are for regression/compatibility:
- I/Os succeed when valid paths exist;
- I/Os fail when there are no valid paths and queue_if_no_path is not
set;
- I/Os are queued in the multipath target when there are no valid paths and
queue_if_no_path is set;
- The queued I/Os above fail when suspend is issued without the
DM_NOFLUSH_FLAG ioctl option. I/Os spanning 2 multipath targets also
fail.
The following tests are for the normal code path of new pushback feature:
- Queued I/Os in the multipath target are flushed from the target
but don't return when suspend is issued with the DM_NOFLUSH_FLAG
ioctl option;
- The I/Os above are queued in the multipath target again when
resume is issued without path recovery;
- The I/Os above succeed when resume is issued after path recovery
or table load;
- Queued I/Os in the multipath target succeed when resume is issued
with the DM_NOFLUSH_FLAG ioctl option after table load. I/Os
spanning 2 multipath targets also succeed.
The following tests are for the error paths of the new pushback feature:
- When the bdget_disk() fails in dm_suspend(), the
DMF_NOFLUSH_SUSPENDING flag is cleared and I/Os already queued to the
pushback list are flushed properly.
- When suspend with the DM_NOFLUSH_FLAG ioctl option is interrupted,
o I/Os which had already been queued to the pushback list
at the time don't return, and are re-issued at resume time;
o I/Os which hadn't been returned at the time return with EIO.
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>
Cc: dm-devel@redhat.com
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 05:41:09 -05:00
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* = 2: The target wants to push back the io
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2005-04-16 18:20:36 -04:00
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*/
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typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
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union map_info *map_context);
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/*
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* Returns:
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* < 0 : error (currently ignored)
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* 0 : ended successfully
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* 1 : for some reason the io has still not completed (eg,
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* multipath target might want to requeue a failed io).
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[PATCH] dm: suspend: add noflush pushback
In device-mapper I/O is sometimes queued within targets for later processing.
For example the multipath target can be configured to store I/O when no paths
are available instead of returning it -EIO.
This patch allows the device-mapper core to instruct a target to transfer the
contents of any such in-target queue back into the core. This frees up the
resources used by the target so the core can replace that target with an
alternative one and then resend the I/O to it. Without this patch the only
way to change the target in such circumstances involves returning the I/O with
an error back to the filesystem/application. In the multipath case, this
patch will let us add new paths for existing I/O to try after all the existing
paths have failed.
DMF_NOFLUSH_SUSPENDING
----------------------
If the DM_NOFLUSH_FLAG ioctl option is specified at suspend time, the
DMF_NOFLUSH_SUSPENDING flag is set in md->flags during dm_suspend(). It
is always cleared before dm_suspend() returns.
The flag must be visible while the target is flushing pending I/Os so it
is set before presuspend where the flush starts and unset after the wait
for md->pending where the flush ends.
Target drivers can check this flag by calling dm_noflush_suspending().
DM_MAPIO_REQUEUE / DM_ENDIO_REQUEUE
-----------------------------------
A target's map() function can now return DM_MAPIO_REQUEUE to request the
device mapper core queue the bio.
Similarly, a target's end_io() function can return DM_ENDIO_REQUEUE to request
the same. This has been labelled 'pushback'.
The __map_bio() and clone_endio() functions in the core treat these return
values as errors and call dec_pending() to end the I/O.
dec_pending
-----------
dec_pending() saves the pushback request in struct dm_io->error. Once all
the split clones have ended, dec_pending() will put the original bio on
the md->pushback list. Note that this supercedes any I/O errors.
It is possible for the suspend with DM_NOFLUSH_FLAG to be aborted while
in progress (e.g. by user interrupt). dec_pending() checks for this and
returns -EIO if it happened.
pushdback list and pushback_lock
--------------------------------
The bio is queued on md->pushback temporarily in dec_pending(), and after
all pending I/Os return, md->pushback is merged into md->deferred in
dm_suspend() for re-issuing at resume time.
md->pushback_lock protects md->pushback.
The lock should be held with irq disabled because dec_pending() can be
called from interrupt context.
Queueing bios to md->pushback in dec_pending() must be done atomically
with the check for DMF_NOFLUSH_SUSPENDING flag. So md->pushback_lock is
held when checking the flag. Otherwise dec_pending() may queue a bio to
md->pushback after the interrupted dm_suspend() flushes md->pushback.
Then the bio would be left in md->pushback.
Flag setting in dm_suspend() can be done without md->pushback_lock because
the flag is checked only after presuspend and the set value is already
made visible via the target's presuspend function.
The flag can be checked without md->pushback_lock (e.g. the first part of
the dec_pending() or target drivers), because the flag is checked again
with md->pushback_lock held when the bio is really queued to md->pushback
as described above. So even if the flag is cleared after the lockless
checkings, the bio isn't left in md->pushback but returned to applications
with -EIO.
Other notes on the current patch
--------------------------------
- md->pushback is added to the struct mapped_device instead of using
md->deferred directly because md->io_lock which protects md->deferred is
rw_semaphore and can't be used in interrupt context like dec_pending(),
and md->io_lock protects the DMF_BLOCK_IO flag of md->flags too.
- Don't issue lock_fs() in dm_suspend() if the DM_NOFLUSH_FLAG
ioctl option is specified, because I/Os generated by lock_fs() would be
pushed back and never return if there were no valid devices.
- If an error occurs in dm_suspend() after the DMF_NOFLUSH_SUSPENDING
flag is set, md->pushback must be flushed because I/Os may be queued to
the list already. (flush_and_out label in dm_suspend())
Test results
------------
I have tested using multipath target with the next patch.
The following tests are for regression/compatibility:
- I/Os succeed when valid paths exist;
- I/Os fail when there are no valid paths and queue_if_no_path is not
set;
- I/Os are queued in the multipath target when there are no valid paths and
queue_if_no_path is set;
- The queued I/Os above fail when suspend is issued without the
DM_NOFLUSH_FLAG ioctl option. I/Os spanning 2 multipath targets also
fail.
The following tests are for the normal code path of new pushback feature:
- Queued I/Os in the multipath target are flushed from the target
but don't return when suspend is issued with the DM_NOFLUSH_FLAG
ioctl option;
- The I/Os above are queued in the multipath target again when
resume is issued without path recovery;
- The I/Os above succeed when resume is issued after path recovery
or table load;
- Queued I/Os in the multipath target succeed when resume is issued
with the DM_NOFLUSH_FLAG ioctl option after table load. I/Os
spanning 2 multipath targets also succeed.
The following tests are for the error paths of the new pushback feature:
- When the bdget_disk() fails in dm_suspend(), the
DMF_NOFLUSH_SUSPENDING flag is cleared and I/Os already queued to the
pushback list are flushed properly.
- When suspend with the DM_NOFLUSH_FLAG ioctl option is interrupted,
o I/Os which had already been queued to the pushback list
at the time don't return, and are re-issued at resume time;
o I/Os which hadn't been returned at the time return with EIO.
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>
Cc: dm-devel@redhat.com
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 05:41:09 -05:00
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* 2 : The target wants to push back the io
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2005-04-16 18:20:36 -04:00
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*/
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typedef int (*dm_endio_fn) (struct dm_target *ti,
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struct bio *bio, int error,
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union map_info *map_context);
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2006-10-03 04:15:43 -04:00
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typedef void (*dm_flush_fn) (struct dm_target *ti);
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2005-04-16 18:20:36 -04:00
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typedef void (*dm_presuspend_fn) (struct dm_target *ti);
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typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
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2006-10-03 04:15:36 -04:00
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typedef int (*dm_preresume_fn) (struct dm_target *ti);
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2005-04-16 18:20:36 -04:00
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typedef void (*dm_resume_fn) (struct dm_target *ti);
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typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
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char *result, unsigned int maxlen);
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typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
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2006-10-03 04:15:15 -04:00
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typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode,
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struct file *filp, unsigned int cmd,
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unsigned long arg);
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2005-04-16 18:20:36 -04:00
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void dm_error(const char *message);
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2006-10-03 04:15:42 -04:00
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/*
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* Combine device limits.
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*/
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void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
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2005-04-16 18:20:36 -04:00
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/*
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* Constructors should call these functions to ensure destination devices
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* are opened/closed correctly.
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* FIXME: too many arguments.
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*/
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int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
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sector_t len, int mode, struct dm_dev **result);
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void dm_put_device(struct dm_target *ti, struct dm_dev *d);
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/*
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* Information about a target type
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*/
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struct target_type {
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const char *name;
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struct module *module;
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2006-06-26 03:27:33 -04:00
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unsigned version[3];
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2005-04-16 18:20:36 -04:00
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dm_ctr_fn ctr;
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dm_dtr_fn dtr;
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dm_map_fn map;
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dm_endio_fn end_io;
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2006-10-03 04:15:43 -04:00
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dm_flush_fn flush;
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2005-04-16 18:20:36 -04:00
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dm_presuspend_fn presuspend;
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dm_postsuspend_fn postsuspend;
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2006-10-03 04:15:36 -04:00
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dm_preresume_fn preresume;
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2005-04-16 18:20:36 -04:00
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dm_resume_fn resume;
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dm_status_fn status;
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dm_message_fn message;
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2006-10-03 04:15:15 -04:00
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dm_ioctl_fn ioctl;
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2005-04-16 18:20:36 -04:00
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};
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struct io_restrictions {
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2006-02-01 06:04:55 -05:00
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unsigned int max_sectors;
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2005-04-16 18:20:36 -04:00
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unsigned short max_phys_segments;
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unsigned short max_hw_segments;
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unsigned short hardsect_size;
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unsigned int max_segment_size;
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unsigned long seg_boundary_mask;
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2006-03-27 04:17:49 -05:00
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unsigned char no_cluster; /* inverted so that 0 is default */
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2005-04-16 18:20:36 -04:00
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};
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struct dm_target {
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struct dm_table *table;
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struct target_type *type;
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/* target limits */
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sector_t begin;
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sector_t len;
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/* FIXME: turn this into a mask, and merge with io_restrictions */
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/* Always a power of 2 */
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sector_t split_io;
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/*
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* These are automatically filled in by
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* dm_table_get_device.
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*/
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struct io_restrictions limits;
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/* target specific data */
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void *private;
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/* Used to provide an error string from the ctr */
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char *error;
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};
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int dm_register_target(struct target_type *t);
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int dm_unregister_target(struct target_type *t);
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2006-06-26 03:27:33 -04:00
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/*-----------------------------------------------------------------
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* Functions for creating and manipulating mapped devices.
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* Drop the reference with dm_put when you finish with the object.
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*---------------------------------------------------------------*/
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/*
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* DM_ANY_MINOR chooses the next available minor number.
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*/
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#define DM_ANY_MINOR (-1)
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int dm_create(int minor, struct mapped_device **md);
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/*
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* Reference counting for md.
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*/
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struct mapped_device *dm_get_md(dev_t dev);
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void dm_get(struct mapped_device *md);
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void dm_put(struct mapped_device *md);
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/*
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* An arbitrary pointer may be stored alongside a mapped device.
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*/
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void dm_set_mdptr(struct mapped_device *md, void *ptr);
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void *dm_get_mdptr(struct mapped_device *md);
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/*
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* A device can still be used while suspended, but I/O is deferred.
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*/
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2006-12-08 05:41:04 -05:00
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int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
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2006-06-26 03:27:33 -04:00
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int dm_resume(struct mapped_device *md);
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/*
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* Event functions.
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*/
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uint32_t dm_get_event_nr(struct mapped_device *md);
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int dm_wait_event(struct mapped_device *md, int event_nr);
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/*
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* Info functions.
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*/
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2006-06-26 03:27:35 -04:00
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const char *dm_device_name(struct mapped_device *md);
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2006-06-26 03:27:33 -04:00
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struct gendisk *dm_disk(struct mapped_device *md);
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int dm_suspended(struct mapped_device *md);
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[PATCH] dm: suspend: add noflush pushback
In device-mapper I/O is sometimes queued within targets for later processing.
For example the multipath target can be configured to store I/O when no paths
are available instead of returning it -EIO.
This patch allows the device-mapper core to instruct a target to transfer the
contents of any such in-target queue back into the core. This frees up the
resources used by the target so the core can replace that target with an
alternative one and then resend the I/O to it. Without this patch the only
way to change the target in such circumstances involves returning the I/O with
an error back to the filesystem/application. In the multipath case, this
patch will let us add new paths for existing I/O to try after all the existing
paths have failed.
DMF_NOFLUSH_SUSPENDING
----------------------
If the DM_NOFLUSH_FLAG ioctl option is specified at suspend time, the
DMF_NOFLUSH_SUSPENDING flag is set in md->flags during dm_suspend(). It
is always cleared before dm_suspend() returns.
The flag must be visible while the target is flushing pending I/Os so it
is set before presuspend where the flush starts and unset after the wait
for md->pending where the flush ends.
Target drivers can check this flag by calling dm_noflush_suspending().
DM_MAPIO_REQUEUE / DM_ENDIO_REQUEUE
-----------------------------------
A target's map() function can now return DM_MAPIO_REQUEUE to request the
device mapper core queue the bio.
Similarly, a target's end_io() function can return DM_ENDIO_REQUEUE to request
the same. This has been labelled 'pushback'.
The __map_bio() and clone_endio() functions in the core treat these return
values as errors and call dec_pending() to end the I/O.
dec_pending
-----------
dec_pending() saves the pushback request in struct dm_io->error. Once all
the split clones have ended, dec_pending() will put the original bio on
the md->pushback list. Note that this supercedes any I/O errors.
It is possible for the suspend with DM_NOFLUSH_FLAG to be aborted while
in progress (e.g. by user interrupt). dec_pending() checks for this and
returns -EIO if it happened.
pushdback list and pushback_lock
--------------------------------
The bio is queued on md->pushback temporarily in dec_pending(), and after
all pending I/Os return, md->pushback is merged into md->deferred in
dm_suspend() for re-issuing at resume time.
md->pushback_lock protects md->pushback.
The lock should be held with irq disabled because dec_pending() can be
called from interrupt context.
Queueing bios to md->pushback in dec_pending() must be done atomically
with the check for DMF_NOFLUSH_SUSPENDING flag. So md->pushback_lock is
held when checking the flag. Otherwise dec_pending() may queue a bio to
md->pushback after the interrupted dm_suspend() flushes md->pushback.
Then the bio would be left in md->pushback.
Flag setting in dm_suspend() can be done without md->pushback_lock because
the flag is checked only after presuspend and the set value is already
made visible via the target's presuspend function.
The flag can be checked without md->pushback_lock (e.g. the first part of
the dec_pending() or target drivers), because the flag is checked again
with md->pushback_lock held when the bio is really queued to md->pushback
as described above. So even if the flag is cleared after the lockless
checkings, the bio isn't left in md->pushback but returned to applications
with -EIO.
Other notes on the current patch
--------------------------------
- md->pushback is added to the struct mapped_device instead of using
md->deferred directly because md->io_lock which protects md->deferred is
rw_semaphore and can't be used in interrupt context like dec_pending(),
and md->io_lock protects the DMF_BLOCK_IO flag of md->flags too.
- Don't issue lock_fs() in dm_suspend() if the DM_NOFLUSH_FLAG
ioctl option is specified, because I/Os generated by lock_fs() would be
pushed back and never return if there were no valid devices.
- If an error occurs in dm_suspend() after the DMF_NOFLUSH_SUSPENDING
flag is set, md->pushback must be flushed because I/Os may be queued to
the list already. (flush_and_out label in dm_suspend())
Test results
------------
I have tested using multipath target with the next patch.
The following tests are for regression/compatibility:
- I/Os succeed when valid paths exist;
- I/Os fail when there are no valid paths and queue_if_no_path is not
set;
- I/Os are queued in the multipath target when there are no valid paths and
queue_if_no_path is set;
- The queued I/Os above fail when suspend is issued without the
DM_NOFLUSH_FLAG ioctl option. I/Os spanning 2 multipath targets also
fail.
The following tests are for the normal code path of new pushback feature:
- Queued I/Os in the multipath target are flushed from the target
but don't return when suspend is issued with the DM_NOFLUSH_FLAG
ioctl option;
- The I/Os above are queued in the multipath target again when
resume is issued without path recovery;
- The I/Os above succeed when resume is issued after path recovery
or table load;
- Queued I/Os in the multipath target succeed when resume is issued
with the DM_NOFLUSH_FLAG ioctl option after table load. I/Os
spanning 2 multipath targets also succeed.
The following tests are for the error paths of the new pushback feature:
- When the bdget_disk() fails in dm_suspend(), the
DMF_NOFLUSH_SUSPENDING flag is cleared and I/Os already queued to the
pushback list are flushed properly.
- When suspend with the DM_NOFLUSH_FLAG ioctl option is interrupted,
o I/Os which had already been queued to the pushback list
at the time don't return, and are re-issued at resume time;
o I/Os which hadn't been returned at the time return with EIO.
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>
Cc: dm-devel@redhat.com
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 05:41:09 -05:00
|
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int dm_noflush_suspending(struct dm_target *ti);
|
2006-06-26 03:27:33 -04:00
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/*
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* Geometry functions.
|
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*/
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int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
|
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int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
|
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|
/*-----------------------------------------------------------------
|
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|
* Functions for manipulating device-mapper tables.
|
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|
|
*---------------------------------------------------------------*/
|
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|
/*
|
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|
* First create an empty table.
|
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|
*/
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|
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int dm_table_create(struct dm_table **result, int mode,
|
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|
|
unsigned num_targets, struct mapped_device *md);
|
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|
/*
|
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|
* Then call this once for each target.
|
|
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|
*/
|
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|
int dm_table_add_target(struct dm_table *t, const char *type,
|
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|
|
sector_t start, sector_t len, char *params);
|
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|
|
/*
|
|
|
|
|
* Finally call this to make the table ready for use.
|
|
|
|
|
*/
|
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|
|
|
int dm_table_complete(struct dm_table *t);
|
|
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|
|
/*
|
|
|
|
|
* Table reference counting.
|
|
|
|
|
*/
|
|
|
|
|
struct dm_table *dm_get_table(struct mapped_device *md);
|
|
|
|
|
void dm_table_get(struct dm_table *t);
|
|
|
|
|
void dm_table_put(struct dm_table *t);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Queries
|
|
|
|
|
*/
|
|
|
|
|
sector_t dm_table_get_size(struct dm_table *t);
|
|
|
|
|
unsigned int dm_table_get_num_targets(struct dm_table *t);
|
|
|
|
|
int dm_table_get_mode(struct dm_table *t);
|
|
|
|
|
struct mapped_device *dm_table_get_md(struct dm_table *t);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Trigger an event.
|
|
|
|
|
*/
|
|
|
|
|
void dm_table_event(struct dm_table *t);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* The device must be suspended before calling this method.
|
|
|
|
|
*/
|
|
|
|
|
int dm_swap_table(struct mapped_device *md, struct dm_table *t);
|
|
|
|
|
|
2006-06-26 03:27:33 -04:00
|
|
|
/*
|
|
|
|
|
* Prepare a table for a device that will error all I/O.
|
|
|
|
|
* To make it active, call dm_suspend(), dm_swap_table() then dm_resume().
|
|
|
|
|
*/
|
|
|
|
|
int dm_create_error_table(struct dm_table **result, struct mapped_device *md);
|
|
|
|
|
|
2006-06-26 03:27:33 -04:00
|
|
|
#endif /* __KERNEL__ */
|
|
|
|
|
#endif /* _LINUX_DEVICE_MAPPER_H */
|
