Commit Graph

49 Commits

Author SHA1 Message Date
Mikulas Patocka
bda8efec5c dm io: use fixed initial mempool size
Replace the arbitrary calculation of an initial io struct mempool size
with a constant.

The code calculated the number of reserved structures based on the request
size and used a "magic" multiplication constant of 4.  This patch changes
it to reserve a fixed number - itself still chosen quite arbitrarily.
Further testing might show if there is a better number to choose.

Note that if there is no memory pressure, we can still allocate an
arbitrary number of "struct io" structures.  One structure is enough to
process the whole request.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-05-29 13:03:09 +01:00
Linus Torvalds
44bbd7ac26 Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm
* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm:
  dm stripe: implement merge method
  dm mpath: allow table load with no priority groups
  dm mpath: fail message ioctl if specified path is not valid
  dm ioctl: add flag to wipe buffers for secure data
  dm ioctl: prepare for crypt key wiping
  dm crypt: wipe keys string immediately after key is set
  dm: add flakey target
  dm: fix opening log and cow devices for read only tables
2011-03-25 20:51:44 -07:00
Milan Broz
024d37e95e dm: fix opening log and cow devices for read only tables
If a table is read-only, also open any log and cow devices it uses read-only.

Previously, even read-only devices were opened read-write internally.
After patch 75f1dc0d07
  block: check bdev_read_only() from blkdev_get()
was applied, loading such tables began to fail.  The patch
was reverted by e51900f7d3
  block: revert block_dev read-only check
but this patch fixes this part of the code to work with the original patch.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-03-24 13:52:14 +00:00
Akinobu Mita
bb5cda3d70 dm: use little-endian bitops
As a preparation for removing ext2 non-atomic bit operations from
asm/bitops.h.  This converts ext2 non-atomic bit operations to
little-endian bit operations.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Alasdair Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:46:20 -07:00
Dan Carpenter
dbc883f157 dm log: use PTR_ERR value instead of ENOMEM
It's nicer to return the PTR_ERR() value instead of just returning
-ENOMEM.  In the current code the PTR_ERR() value is always equal to
-ENOMEM so this doesn't actually affect anything, but still...

In addition, dm_dirty_log_create() doesn't check for a specific -ENOMEM
return.  So this change is safe relative to potential for a non -ENOMEM
return in the future.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-01-13 20:00:00 +00:00
Tejun Heo
d87f4c14f2 dm: implement REQ_FLUSH/FUA support for bio-based dm
This patch converts bio-based dm to support REQ_FLUSH/FUA instead of
now deprecated REQ_HARDBARRIER.

* -EOPNOTSUPP handling logic dropped.

* Preflush is handled as before but postflush is dropped and replaced
  with passing down REQ_FUA to member request_queues.  This replaces
  one array wide cache flush w/ member specific FUA writes.

* __split_and_process_bio() now calls __clone_and_map_flush() directly
  for flushes and guarantees all FLUSH bio's going to targets are zero
`  length.

* It's now guaranteed that all FLUSH bio's which are passed onto dm
  targets are zero length.  bio_empty_barrier() tests are replaced
  with REQ_FLUSH tests.

* Empty WRITE_BARRIERs are replaced with WRITE_FLUSHes.

* Dropped unlikely() around REQ_FLUSH tests.  Flushes are not unlikely
  enough to be marked with unlikely().

* Block layer now filters out REQ_FLUSH/FUA bio's if the request_queue
  doesn't support cache flushing.  Advertise REQ_FLUSH | REQ_FUA
  capability.

* Request based dm isn't converted yet.  dm_init_request_based_queue()
  resets flush support to 0 for now.  To avoid disturbing request
  based dm code, dm->flush_error is added for bio based dm while
  requested based dm continues to use dm->barrier_error.

Lightly tested linear, stripe, raid1, snap and crypt targets.  Please
proceed with caution as I'm not familiar with the code base.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: dm-devel@redhat.com
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-09-10 12:35:38 +02:00
Nikanth Karthikesan
8215d6ec5f dm table: remove unused dm_get_device range parameters
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>
2010-03-06 02:32:27 +00:00
Mikulas Patocka
64b30c46e8 dm raid1: report flush errors separately in status
Report flush errors as 'F' instead of 'D' for log and mirror devices.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:52:02 +00:00
Mikulas Patocka
076010e2e6 dm log: use flush callback fn
Call the flush callback from the log.

If flush failed, we have no alternative but to mark the whole log as dirty.
Also we set the variable flush_failed to prevent any bits ever being marked as
clean again.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:52:01 +00:00
Mikulas Patocka
87a8f240e9 dm log: add flush callback fn
Introduce a callback pointer from the log to dm-raid1 layer.

Before some region is set as "in-sync", we need to flush hardware cache on
all the disks. But the log module doesn't have access to the mirror_set
structure. So it will use this callback.

So far the callback is unused, it will be used in further patches.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:52:01 +00:00
Mikulas Patocka
5adc78d0d2 dm log: introduce flush_failed variable
Introduce "flush failed" variable.  When a flush before clearing a bit
in the log fails, we don't know anything about which which regions are
in-sync and which not.

So we need to set all regions as not-in-sync and set the variable
"flush_failed" to prevent setting the in-sync bit in the future.

A target reload is the only way to get out of this situation.

The variable will be set in following patches.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:52:00 +00:00
Mikulas Patocka
20a34a8ecc dm log: add flush_header function
Introduce flush_header and use it to flush the log device.

Note that we don't have to flush if all the regions transition
from "dirty" to "clean" state.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:52:00 +00:00
Mikulas Patocka
b09acf1aa7 dm raid1: split touched state into two
Split the variable "touched" into two, "touched_dirtied" and
"touched_cleaned", set when some region was dirtied or cleaned.

This will be used to optimize flushes.

After a transition from "dirty" to "clean" state we don't have flush hardware
cache on the log device. After a transition from "clean" to "dirty" the cache
must be flushed.

Before a transition from "clean" to "dirty" state we don't have to flush all
the raid legs. Before a transition from "dirty" to "clean" we must flush all
the legs to make sure that they are really in sync.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:51:59 +00:00
Mike Snitzer
18d8594dd9 dm log: fix create_log_context to use logical_block_size of log device
create_log_context() must use the logical_block_size from the log disk,
where the I/O happens, not the target's logical_block_size.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22 10:12:33 +01:00
Mikulas Patocka
5657e8fa45 dm: use i_size_read
Use i_size_read() instead of reading i_size.

If someone changes the size of the device simultaneously, i_size_read
is guaranteed to return a valid value (either the old one or the new one).

i_size can return some intermediate invalid value (on 32-bit computers
with 64-bit i_size, the reads to both halves of i_size can be interleaved
with updates to i_size, resulting in garbage being returned).

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22 10:12:14 +01:00
Martin K. Petersen
e1defc4ff0 block: Do away with the notion of hardsect_size
Until now we have had a 1:1 mapping between storage device physical
block size and the logical block sized used when addressing the device.
With SATA 4KB drives coming out that will no longer be the case.  The
sector size will be 4KB but the logical block size will remain
512-bytes.  Hence we need to distinguish between the physical block size
and the logical ditto.

This patch renames hardsect_size to logical_block_size.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:54 +02:00
Mike Snitzer
ec44ab9d66 dm log: remove struct dm_dirty_log_internal
Remove the 'dm_dirty_log_internal' structure.  The resulting cleanup
eliminates extra memory allocations.  Therefore exposing the internal
list_head to the external 'dm_dirty_log_type' structure is a worthwhile
compromise.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:30 +01:00
Mike Snitzer
84e67c9319 dm log: use standard kernel module refcount
Avoid private module usage accounting by removing 'use' from
dm_dirty_log_internal.  The standard module reference counting is
sufficient.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:29 +01:00
Milan Broz
ac1f0ac22c dm log: ensure log bitmap fits on log device
Check that the log bitmap will fit within the log device.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-01-06 03:05:02 +00:00
Milan Broz
2045e88edb dm log: move region_size validation
Move log size validation from mirror target to log constructor.

Removed PAGE_SIZE restriction we no longer think necessary.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-01-06 03:05:01 +00:00
Takahiro Yasui
6f3af01cb0 dm log: avoid reinitialising io_req on every operation
rw_header function updates three members of io_req data every time
when I/O is processed. bi_rw and notify.fn are never modified once
they get initialized, and so they can be set in advance.

header_to_disk() can also be pulled out of write_header() since only one
caller needs it and write_header() can be replaced by rw_header()
directly.

Signed-off-by: Takahiro Yasui <tyasui@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-01-06 03:04:59 +00:00
Takahiro Yasui
c7a2bd19b7 dm log: fix dm_io_client leak on error paths
In create_log_context function, dm_io_client_destroy function needs
to be called, when memory allocation of disk_header, sync_bits and
recovering_bits failed, but dm_io_client_destroy is not called.

Cc: stable@kernel.org
Signed-off-by: Takahiro Yasui <tyasui@redhat.com>
Acked-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-01-06 03:04:56 +00:00
Mikulas Patocka
586e80e6ee dm: remove dm header from targets
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>
2008-10-21 17:44:59 +01:00
Adrian Bunk
c8da2f8dd8 dm log: make dm_dirty_log init and exit static
dm_dirty_log_{init,exit}() can now become static.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-07-21 12:00:27 +01:00
Alasdair G Kergon
a765e20eeb dm: move include files
Publish the dm-io, dm-log and dm-kcopyd headers in include/linux.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-04-25 13:26:55 +01:00
Jonathan Brassow
2a23aa1ddb dm log: make module use tracking internal
Remove internal module reference fields from the interface.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-04-25 13:26:48 +01:00
Alasdair G Kergon
b8206bc3de dm log: move register functions
Reorder a couple of functions in the file so the next patch is readable.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-04-25 13:26:47 +01:00
Heinz Mauelshagen
416cd17b19 dm log: clean interface
Clean up the dm-log interface to prepare for publishing it in include/linux.

Signed-off-by: Heinz Mauelshagen <hjm@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-04-25 13:26:46 +01:00
Heinz Mauelshagen
22a1ceb1e6 dm io: clean interface
Clean up the dm-io interface to prepare for publishing it in include/linux.

Signed-off-by: Heinz Mauelshagen <hjm@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-04-25 13:26:43 +01:00
Heinz Mauelshagen
769aef30f0 dm log: move dirty region log code into separate module
Move the dirty region log code into a separate module so
other targets can share the code.

Signed-off-by: Heinz Mauelshagen <hjm@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-04-25 13:26:39 +01:00
Heinz Mauelshagen
b7fd54a70f dm log: generalise name in messages
Change dm-log.c messages from "mirror log" to "dirty region log" as
a new dm target wants to share this code.

Signed-off-by: Heinz Mauelshagen <hjm@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-04-25 13:26:38 +01:00
Jonathan Brassow
fb8b284806 dm log: auto load modules
If the log type is not recognised, attempt to load the module
'dm-log-<type>.ko'.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-02-08 02:11:19 +00:00
Jonathan Brassow
6b3df0d7a5 dm log: split suspend
There are now two phases to a suspend in device-mapper -
presuspend and postsuspend.  This patch removes the
single 'suspend' in the logging API and replaces it with
'presuspend' and 'postsuspend' functions to align it
better with core device-mapper.

A subsequent patch will make use of 'presuspend'.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2007-10-20 02:01:21 +01:00
Jonathan Brassow
ba8b45cea5 dm log: fix resume failed log device
This patch removes the possibility of having uninitialized log state if the
log device has failed.

When a mirror resumes operation, it calls 'resume' on the logging module.  If
disk based logging is being used, the log device is read to fill in the log
state.  If the log device has failed, we cannot simply return, because this
would leave the in-memory log state uninitialized.  Instead, we assume all
regions are out-of-sync and reset the log state.  Failure to do this could
result in the logging code reporting a region as in-sync, even though it
isn't; which could result in a corrupted mirror.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:48 -07:00
Heinz Mauelshagen
5d234d1e03 dm log: update dm io interface
This patch ports dm-log.c to the new dm-io interface in order to make it
scalable to have a large number of persistent dirty logs active in parallel.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Cc: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:47 -07:00
Jonathan E Brassow
315dcc226f dm log: report fault status
This patch reports the status of the log device so that userspace can detect
the error and take appropriate action.

Signed-off-by: Jonathan E Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:47 -07:00
Jonathan E Brassow
01d03a660e dm log: fault detection
This patch gives the disk logging code the ability to store the fact that an
error occured on the log device.  In addition, an event is raised when an
error is encountered during I/O to the log device.

Signed-off-by: Jonathan E Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:47 -07:00
Jonathan E Brassow
88b20a1a71 [PATCH] dm: raid1: reset sync_search on resume
Reset sync_search on resume.  The effect is to retry syncing all out-of-sync
regions when a mirror is resumed, including ones that previously failed.

Signed-off-by: Jonathan E Brassow <jbrassow@redhat.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 08:29:09 -08:00
Jonathan E Brassow
f3ee6b2f62 [PATCH] dm: log: rename complete_resync_work
The complete_resync_work function only provides the ability to change an
out-of-sync region to in-sync.  This patch enhances the function to allow us
to change the status from in-sync to out-of-sync as well, something that is
needed when a mirror write to one of the devices or an initial resync on a
given region fails.

Signed-off-by: Jonathan E Brassow <jbrassow@redhat.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 08:29:09 -08:00
Alasdair G Kergon
72d9486169 [PATCH] dm: improve error message consistency
Tidy device-mapper error messages to include context information
automatically.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:36 -07:00
Alasdair G Kergon
8a835f11bc [PATCH] dm mirror log: sync_count fix
When a mirror is reduced in size, clear the part of the bitmap that is no
longer used.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:35 -07:00
Alasdair G Kergon
29121bd0b0 [PATCH] dm mirror log: bitset_size fix
Fix the 'sizeof' in the region log bitmap size calculation: it's uint32_t, not
unsigned long - this breaks on some archs.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:35 -07:00
Alasdair G Kergon
b7cca195c4 [PATCH] dm mirror log: refactor context
Refactor the code that creates the core and disk log contexts to avoid the
repeated allocation of clean_bits introduced by the last patch.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:35 -07:00
Kevin Corry
702ca6f0be [PATCH] dm mirror log: sector size fix
On-disk logs for dm-mirror devices are currently hard-coded to use 512 byte
hard-sector-sizes.  This patch fixes dm-log so it will work with devices with
non-512-byte hard-sector-sizes.

To maintain full compatibility, instead of moving the clean-bits bitset to a
bitset, and enlarges the disk-header buffer to encompass both the header and
the bitset.  The I/O routines for the bitset are removed, and the I/O routines
for the disk-header now also read/write the bitset.

Signed-off-by: Kevin Corry <kevcorry@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:35 -07:00
Stefan Bader
1113a7e92e [PATCH] device-mapper log bitset: fix big endian find_next_zero_bit
This is a fix to the device-mapper-log-bitset-fix-endian patch that
switched to ext2_* versions of the set and clear bit functions.  The
find_next_zero_bit function also has to be the ext2 one.  Otherwise the
mirror target tries to recover non-existent regions beyond the end of
device.

Signed-off-by: Stefan Bader <shbader@de.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-02 15:07:13 -08:00
Patrick Caulfield
a4fc4717fc [PATCH] device-mapper log bitset: fix endian
Clean up the code responsible for the on-disk mirror logs by using the
set_le_bit test_le_bit functions of ext2.  That makes the BE machines keep the
bitmap internally in LE order - it does mean you can't use any other type of
operations on the bitmap words but that looks to be OK in this instance.  The
efficiency tradeoff is very minimal as you would expect for something that
ext2 uses.

This allows us to remove bits_to_core(), bits_to_disk() and log->disk_bits.

Also increment the mirror log disk version transparently to avoid sharing with
older kernels that suffered from the 64-bit BE bug.

Signed-off-by: Patrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01 08:53:10 -08:00
Darrick J. Wong
ac81b2ee45 [PATCH] make dm-mirror not issue invalid resync requests
I've been attempting to set up a (Host)RAID mirror with dm_mirror on
2.6.14.3, and I've been having a strange little problem.  The configuration
in question is a set of 9GB SCSI disks that have 17942584 sectors.  I set
up the dm_mirror table as such:

0 17942528 mirror core 2 2048 nosync 2 8:48 0 8:64 0

If I'm not mistaken, this sets up a 9GB RAID1 mriror with 1MB stripes
across both SCSI disks.  The sector count of the dm device is less than the
size of the disks, so we shouldn't fall off the end.  However, I always get
the messages like this in dmesg when I set up the dm table:

attempt to access beyond end of device
sdd: rw=0, want=17958656, limit=17942584

Clearly, something is trying to read sectors past the end of the drive.  I
traced it down to the __rh_recovery_prepare function in dm-raid1.c, which
gets called when we're putting the mirror set together.  This function
calls the dirty region log's get_resync_work function to see if there's any
resync that needs to be done, and queues up any areas that are out of sync.
 The log's get_resync_work function is actually a pointer to the
core_get_resync_work function in dm-log.c.

The core_get_resync_work function queries a bitset lc->sync_bits to find
out if there are any regions that are out of date (i.e.  the bit is 0),
which is where the problem occurs.  If every bit in lc->sync_bits is 1
(which is the case when we've just configured a new RAID1 with the nosync
option), the find_next_zero_bit does NOT return the size parameter
(lc->region_count in this case), it returns the size parameter rounded up
to the nearest multiple of 32!  I don't know if this is intentional, but
i386 and x86_64 both exhibit this behavior.

In any case, the statement "if (*region == lc->region_count)" looks like
it's supposed to catch the case where are no regions to resync and
return 0.  Since find_next_zero_bit apparently has a habit of returning
a value that's larger than lc->region_count, the enclosed patch changes
the equality test to a greater-than test so that we don't try to resync
areas outside of the RAID1 region.  Seeing as the HostRAID metadata
lives just past the end of the RAID1 data, mucking around in that area
is not a good idea.

I suppose another way to fix this would be to amend find_next_zero_bit so
that it doesn't return values larger than "size", but I don't know if
there's a reason for the current behavior.

Signed-Off-By: Darrick J. Wong <djwong@us.ibm.com>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:34:01 -08:00
Alasdair G Kergon
0e56822d30 [PATCH] device-mapper: mirror log bitset fix
The linux bitset operators (test_bit, set_bit etc) work on arrays of "unsigned
long".  dm-log uses such bitsets but treats them as arrays of uint32_t, only
allocating and zeroing a multiple of 4 bytes (as 'clean_bits' is a uint32_t).

The patch below fixes this problem.

The problem is specific to 64-bit big endian machines such as s390x or ppc-64
and can prevent pvmove terminating.

In the simplest case, if "region_count" were (say) 30, then
bitset_size (below) would be 4 and bitset_uint32_count would be 1.
Thus the memory for this butset, after allocation and zeroing would
be
   0 0 0 0 X X X X
On a bigendian 64bit machine, bit 0 for this bitset is in the 8th
byte! (and every bit that dm-log would use would be in the X area).

   0 0 0 0 X X X X
                 ^
                 here

which hasn't been cleared properly.

As the dm-raid1 code only syncs and counts regions which have a 0 in the
'sync_bits' bitset, and only finishes when it has counted high enough, a large
number of 1's among those 'X's will cause the sync to not complete.

It is worth noting that the code uses the same bitsets for in-memory and
on-disk logs.  As these bitsets are host-endian and host-sized, this means
that they cannot safely be moved between computers with

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-22 09:14:31 -08:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00