Commit Graph

1120 Commits

Author SHA1 Message Date
Jonathan Brassow
49beb2b87a dm exception store: move cow pointer
Move COW device from snapshot to exception store.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:33 +01:00
Jonathan Brassow
d021684951 dm exception store: move chunk_fields
Move chunk fields from snapshot to exception store.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:32 +01:00
Jonathan Brassow
0cea9c7827 dm exception store: move dm_target pointer
Move target pointer from snapshot to exception store.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:32 +01:00
Jonathan Brassow
493df71c64 dm exception store: introduce registry
Move exception stores into a registry.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:31 +01:00
Jonathan Brassow
7513c2a761 dm raid1: add is_remote_recovering hook for clusters
The logging API needs an extra function to make cluster mirroring
possible.  This new function allows us to check whether a mirror
region is being recovered on another machine in the cluster.  This
helps us prevent simultaneous recovery I/O and process I/O to the
same locations on disk.

Cluster-aware log modules will implement this function.  Single
machine log modules will not.  So, there is no performance
penalty for single machine mirrors.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Acked-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:30 +01:00
Jonathan Brassow
b2a1146529 dm exception store: separate type from instance
Introduce struct dm_exception_store_type.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:30 +01:00
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
Johannes Weiner
b81d6cf79b dm crypt: use kzfree
Use kzfree() instead of memset() + kfree().

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:28 +01:00
Cheng Renquan
45194e4f89 dm target: remove struct tt_internal
The tt_internal is really just a list_head to manage registered target_type
in a double linked list,

Here embed the list_head into target_type directly,
1. to avoid kmalloc/kfree;
2. then tt_internal is really unneeded;

Cc: stable@kernel.org
Signed-off-by: Cheng Renquan <crquan@gmail.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Reviewed-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:28 +01:00
Alasdair G Kergon
570b9d968b dm table: fix upgrade mode race
upgrade_mode() sets bdev to NULL temporarily, and does not have any
locking to exclude anything from seeing that NULL.

In dm_table_any_congested() bdev_get_queue() can dereference that NULL and
cause a reported oops.

Fix this by not changing that field during the mode upgrade.

Cc: stable@kernel.org
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:28 +01:00
Jun'ichi Nomura
aea9058801 dm: path selector use module refcount directly
Fix refcount corruption in dm-path-selector

Refcounting with non-atomic ops under shared lock will corrupt the counter
in multi-processor system and may trigger BUG_ON().
Use module refcount.
# same approach as dm-target-use-module-refcount-directly.patch here
# https://www.redhat.com/archives/dm-devel/2008-December/msg00075.html

Typical oops:
  kernel BUG at linux-2.6.29-rc3/drivers/md/dm-path-selector.c:90!
  Pid: 11148, comm: dmsetup Not tainted 2.6.29-rc3-nm #1
  dm_put_path_selector+0x4d/0x61 [dm_multipath]
  Call Trace:
   [<ffffffffa031d3f9>] free_priority_group+0x33/0xb3 [dm_multipath]
   [<ffffffffa031d4aa>] free_multipath+0x31/0x67 [dm_multipath]
   [<ffffffffa031d50d>] multipath_dtr+0x2d/0x32 [dm_multipath]
   [<ffffffffa015d6c2>] dm_table_destroy+0x64/0xd8 [dm_mod]
   [<ffffffffa015b73a>] __unbind+0x46/0x4b [dm_mod]
   [<ffffffffa015b79f>] dm_swap_table+0x60/0x14d [dm_mod]
   [<ffffffffa015f963>] dev_suspend+0xfd/0x177 [dm_mod]
   [<ffffffffa0160250>] dm_ctl_ioctl+0x24c/0x29c [dm_mod]
   [<ffffffff80288cd3>] ? get_page_from_freelist+0x49c/0x61d
   [<ffffffffa015f866>] ? dev_suspend+0x0/0x177 [dm_mod]
   [<ffffffff802bf05c>] vfs_ioctl+0x2a/0x77
   [<ffffffff802bf4f1>] do_vfs_ioctl+0x448/0x4a0
   [<ffffffff802bf5a0>] sys_ioctl+0x57/0x7a
   [<ffffffff8020c05b>] system_call_fastpath+0x16/0x1b

Cc: stable@kernel.org
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:27 +01:00
Cheng Renquan
5642b8a61a dm target: use module refcount directly
The tt_internal's 'use' field is superfluous: the module's refcount can do
the work properly.  An acceptable side-effect is that this increases the
reference counts reported by 'lsmod'.

Remove the superfluous test when removing a target module.

[Crash possible without this on SMP - agk]

Cc: stable@kernel.org
Signed-off-by: Cheng Renquan <crquan@gmail.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Reviewed-by: Alasdair G Kergon <agk@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
2009-04-02 19:55:27 +01:00
Mikulas Patocka
35bf659b00 dm snapshot: avoid having two exceptions for the same chunk
We need to check if the exception was completed after dropping the lock.

After regaining the lock, __find_pending_exception checks if the exception
was already placed into &s->pending hash.

But we don't check if the exception was already completed and placed into
&s->complete hash. If the process waiting in alloc_pending_exception was
delayed at this point because of a scheduling latency and the exception
was meanwhile completed, we'd miss that and allocate another pending
exception for already completed chunk.

It would lead to a situation where two records for the same chunk exist
and potential data corruption because multiple snapshot I/Os to the
affected chunk could be redirected to different locations in the
snapshot.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:26 +01:00
Mikulas Patocka
c66213921c dm snapshot: avoid dropping lock in __find_pending_exception
It is uncommon and bug-prone to drop a lock in a function that is called with
the lock held, so this is moved to the caller.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:25 +01:00
Mikulas Patocka
2913808eb5 dm snapshot: refactor __find_pending_exception
Move looking-up of a pending exception from __find_pending_exception to another
function.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:25 +01:00
Mikulas Patocka
b64b6bf4fd dm io: make sync_io uninterruptible
If someone sends signal to a process performing synchronous dm-io call,
the kernel may crash.

The function sync_io attempts to exit with -EINTR if it has pending signal,
however the structure "io" is allocated on stack, so already submitted io
requests end up touching unallocated stack space and corrupting kernel memory.

sync_io sets its state to TASK_UNINTERRUPTIBLE, so the signal can't break out
of io_schedule() --- however, if the signal was pending before sync_io entered
while (1) loop, the corruption of kernel memory will happen.

There is no way to cancel in-progress IOs, so the best solution is to ignore
signals at this point.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:24 +01:00
Mikulas Patocka
95f8fac8dc dm raid1: switch read_record from kmalloc to slab to save memory
With my previous patch to save bi_io_vec, the size of dm_raid1_read_record
is significantly increased (the vector list takes 3072 bytes on 32-bit machines
and 4096 bytes on 64-bit machines).

The structure dm_raid1_read_record used to be allocated with kmalloc,
but kmalloc aligns the size on the next power-of-two so an object
slightly greater than 4096 will allocate 8192 bytes of memory and half of
that memory will be wasted.

This patch turns kmalloc into a slab cache which doesn't have this
padding so it will reduce the memory consumed.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:24 +01:00
Mikulas Patocka
a920f6b3ac dm: preserve bi_io_vec when resubmitting bios
Device mapper saves and restores various fields in the bio, but it doesn't save
bi_io_vec.  If the device driver modifies this after a partially successful
request, dm-raid1 and dm-multipath may attempt to resubmit a bio that has
bi_size inconsistent with the size of vector.

To make requests resubmittable in dm-raid1 and dm-multipath, we must save
and restore the bio vector as well.

To reduce the memory overhead involved in this, we do not save the pages in a
vector and use a 16-bit field size if the page size is less than 65536.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:23 +01:00
Milan Broz
b35f8caa08 dm crypt: wait for endio to complete before destruction
The following oops has been reported when dm-crypt runs over a loop device.

...
[   70.381058] Process loop0 (pid: 4268, ti=cf3b2000 task=cf1cc1f0 task.ti=cf3b2000)
...
[   70.381058] Call Trace:
[   70.381058]  [<d0d76601>] ? crypt_dec_pending+0x5e/0x62 [dm_crypt]
[   70.381058]  [<d0d767b8>] ? crypt_endio+0xa2/0xaa [dm_crypt]
[   70.381058]  [<d0d76716>] ? crypt_endio+0x0/0xaa [dm_crypt]
[   70.381058]  [<c01a2f24>] ? bio_endio+0x2b/0x2e
[   70.381058]  [<d0806530>] ? dec_pending+0x224/0x23b [dm_mod]
[   70.381058]  [<d08066e4>] ? clone_endio+0x79/0xa4 [dm_mod]
[   70.381058]  [<d080666b>] ? clone_endio+0x0/0xa4 [dm_mod]
[   70.381058]  [<c01a2f24>] ? bio_endio+0x2b/0x2e
[   70.381058]  [<c02bad86>] ? loop_thread+0x380/0x3b7
[   70.381058]  [<c02ba8a1>] ? do_lo_send_aops+0x0/0x165
[   70.381058]  [<c013754f>] ? autoremove_wake_function+0x0/0x33
[   70.381058]  [<c02baa06>] ? loop_thread+0x0/0x3b7

When a table is being replaced, it waits for I/O to complete
before destroying the mempool, but the endio function doesn't
call mempool_free() until after completing the bio.

Fix it by swapping the order of those two operations.

The same problem occurs in dm.c with md referenced after dec_pending.
Again, we swap the order.

Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-03-16 17:44:36 +00:00
Huang Ying
b2174eebd1 dm crypt: fix kcryptd_async_done parameter
In the async encryption-complete function (kcryptd_async_done), the
crypto_async_request passed in may be different from the one passed to
crypto_ablkcipher_encrypt/decrypt.  Only crypto_async_request->data is
guaranteed to be same as the one passed in.  The current
kcryptd_async_done uses the passed-in crypto_async_request directly
which may cause the AES-NI-based AES algorithm implementation to panic.

This patch fixes this bug by only using crypto_async_request->data,
which points to dm_crypt_request, the crypto_async_request passed in.
The original data (convert_context) is gotten from dm_crypt_request.

[mbroz@redhat.com: reworked]
Cc: stable@kernel.org
Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-03-16 17:44:33 +00:00
Mikulas Patocka
d659e6cc98 dm io: respect BIO_MAX_PAGES limit
dm-io calls bio_get_nr_vecs to get the maximum number of pages to use
for a given device.  It allocates one additional bio_vec to use
internally but failed to respect BIO_MAX_PAGES, so fix this.

This was the likely cause of:
  https://bugzilla.redhat.com/show_bug.cgi?id=173153

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-03-16 17:44:30 +00:00
Mikulas Patocka
f80a557008 dm table: rework reference counting fix
Fix an error introduced in dm-table-rework-reference-counting.patch.

When there is failure after table initialization, we need to use
dm_table_destroy, not dm_table_put, to free the table.

dm_table_put may be used only after dm_table_get.

Cc: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-03-16 17:44:26 +00:00
Milan Broz
bc0fd67feb dm ioctl: validate name length when renaming
When renaming a mapped device validate the length of the new name.

The rename ioctl accepted any correctly-terminated string enclosed
within the data passed from userspace.  The other ioctls enforce a
size limit of DM_NAME_LEN.  If the name is changed and becomes longer
than that, the device can no longer be addressed by name.

Fix it by properly checking for device name length (including
terminating zero).

Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-03-16 16:56:01 +00:00
Dan Williams
5fd3a17ed4 md: fix deadlock when stopping arrays
Resolve a deadlock when stopping redundant arrays, i.e. ones that
require a call to sysfs_remove_group when shutdown.  The deadlock is
summarized below:

Thread1                Thread2
-------                -------
read sysfs attribute   stop array
                       take mddev lock
                       sysfs_remove_group
sysfs_get_active
wait for mddev lock
                       wait for active

Sysrq-w:
--------
mdmon         S 00000017  2212  4163      1
  f1982ea8 00000046 2dcf6b85 00000017 c0b23100 f2f83ed0 c0b23100 f2f8413c
  c0b23100 c0b23100 c0b1fb98 f2f8413c 00000000 f2f8413c c0b23100 f2291ecc
  00000002 c0b23100 00000000 00000017 f2f83ed0 f1982eac 00000046 c044d9dd
Call Trace:
  [<c044d9dd>] ? debug_mutex_add_waiter+0x1d/0x58
  [<c06ef451>] __mutex_lock_common+0x1d9/0x338
  [<c06ef451>] ? __mutex_lock_common+0x1d9/0x338
  [<c06ef5e3>] mutex_lock_interruptible_nested+0x33/0x3a
  [<c0634553>] ? mddev_lock+0x14/0x16
  [<c0634553>] mddev_lock+0x14/0x16
  [<c0634eda>] md_attr_show+0x2a/0x49
  [<c04e9997>] sysfs_read_file+0x93/0xf9
mdadm         D 00000017  2812  4177      1
  f0401d78 00000046 430456f8 00000017 f0401d58 f0401d20 c0b23100 f2da2c4c
  c0b23100 c0b23100 c0b1fb98 f2da2c4c 0a10fc36 00000000 c0b23100 f0401d70
  00000003 c0b23100 00000000 00000017 f2da29e0 00000001 00000002 00000000
Call Trace:
  [<c06eed1b>] schedule_timeout+0x1b/0x95
  [<c06eed1b>] ? schedule_timeout+0x1b/0x95
  [<c06eeb97>] ? wait_for_common+0x34/0xdc
  [<c044fa8a>] ? trace_hardirqs_on_caller+0x18/0x145
  [<c044fbc2>] ? trace_hardirqs_on+0xb/0xd
  [<c06eec03>] wait_for_common+0xa0/0xdc
  [<c0428c7c>] ? default_wake_function+0x0/0x12
  [<c06eeccc>] wait_for_completion+0x17/0x19
  [<c04ea620>] sysfs_addrm_finish+0x19f/0x1d1
  [<c04e920e>] sysfs_hash_and_remove+0x42/0x55
  [<c04eb4db>] sysfs_remove_group+0x57/0x86
  [<c0638086>] do_md_stop+0x13a/0x499

This has been there for a while, but is easier to trigger now that mdmon
is closely watching sysfs.

Cc: <stable@kernel.org>
Reported-by: Jacek Danecki <jacek.danecki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 00:57:25 -07:00
NeilBrown
73d5c38a95 md: avoid races when stopping resync.
There has been a race in raid10 and raid1 for a long time
which has only recently started showing up due to a scheduler changed.

When a sync_read request finishes, as soon as reschedule_retry
is called, another thread can mark the resync request as having
completed, so md_do_sync can finish, ->stop can be called, and
->conf can be freed.  So using conf after reschedule_retry is not
safe.

Similarly, when finishing a sync_write, calling md_done_sync must be
the last thing we do, as it allows a chain of events which will free
conf and other data structures.

The first of these requires action in raid10.c
The second requires action in raid1.c and raid10.c

Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
2009-02-25 13:18:47 +11:00
NeilBrown
78200d45cd md/raid10: Don't call bitmap_cond_end_sync when we are doing recovery.
For raid1/4/5/6, resync (fixing inconsistencies between devices) is
very similar to recovery (rebuilding a failed device onto a spare).
The both walk through the device addresses in order.

For raid10 it can be quite different.  resync follows the 'array'
address, and makes sure all copies are the same.  Recover walks
through 'device' addresses and recreates each missing block.

The 'bitmap_cond_end_sync' function allows the write-intent-bitmap
(When present) to be updated to reflect a partially completed resync.
It makes assumptions which mean that it does not work correctly for
raid10 recovery at all.

In particularly, it can cause bitmap-directed recovery of a raid10 to
not recovery some of the blocks that need to be recovered.

So move the call to bitmap_cond_end_sync into the resync path, rather
than being in the common "resync or recovery" path.


Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
2009-02-25 13:18:47 +11:00
NeilBrown
09b4068a7f md/raid10: Don't skip more than 1 bitmap-chunk at a time during recovery.
When doing recovery on a raid10 with a write-intent bitmap, we only
need to recovery chunks that are flagged in the bitmap.

However if we choose to skip a chunk as it isn't flag, the code
currently skips the whole raid10-chunk, thus it might not recovery
some blocks that need recovering.

This patch fixes it.

In case that is confusing, it might help to understand that there
is a 'raid10 chunk size' which guides how data is distributed across
the devices, and a 'bitmap chunk size' which says how much data
corresponds to a single bit in the bitmap.

This bug only affects cases where the bitmap chunk size is smaller
than the raid10 chunk size.



Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
2009-02-25 13:18:47 +11:00
Jens Axboe
93dbb39350 block: fix bad definition of BIO_RW_SYNC
We can't OR shift values, so get rid of BIO_RW_SYNC and use BIO_RW_SYNCIO
and BIO_RW_UNPLUG explicitly. This brings back the behaviour from before
213d9417fe.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-02-18 10:32:00 +01:00
NeilBrown
de01dfadf2 md: Ensure an md array never has too many devices.
Each different metadata format supported by md supports a
different maximum number of devices.
We really should be enforcing this maximum in the kernel, but
we aren't quite doing that properly.

We currently only enforce it at the 'hot_add' point, which is an
older interface which is not used by current userspace.

We need to also enforce it at 'add_new_disk' time for active arrays
and at 'do_md_run' time when starting a new array.

So move the test from 'hot_add' into 'bind_rdev_to_array' which is
called from both 'hot_add' and 'add_new_disk, and add a new
test in 'analyse_sbs' which is called from 'do_md_run'.

This bug (or missing feature) has been around "forever" and so
the patch is suitable for any -stable that is currently maintained.

Cc: stable@kernel.org

Signed-off-by: NeilBrown <neilb@suse.de>
2009-02-06 18:02:46 +11:00
Andre Noll
852c8bf484 md: Fix a bug in linear.c causing which_dev() to return the wrong device.
ab5bd5cbc8 introduced the following
bug in linear software raid for large arrays on 32 bit machines:

which_dev() computes the device holding a given sector by shifting
down the sector number to a 32 bit range, dividing by the array
spacing and looking up the resulting index in the hash table of
the array.

Because the computed index might be slightly too small, a loop at
the end of which_dev() increases the index until the given sector
actually falls into the range of the device associated with that index.

The changes of the above mentioned commit caused this loop to check
whether the _index_ rather than the sector number is small enough,
effectively bypassing the loop and thus possibly returning the wrong
device.

As reported by Simon Kirby, this leads to errors such as

	linear_make_request: Sector 2340486136 out of bounds on dev sdi: 156301312 sectors, offset 2109870464

Fix this bug by introducing a local variable for the index so that
the variable containing the passed sector is left unchanged.

Cc: stable@kernel.org
Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-02-06 15:10:52 +11:00
NeilBrown
4706b349f4 md: Allow read error in a single drive raid1 to be passed up.
If a raid1 only has a single working device and gets a read error, 
we choose to simply return that error up to the filesystem (or whatever)
rather than failing the whole array.

However the codes doesn't quite do that.  We attempt a readbalance
which allocates the same drive, so we retry the read - indefinitely. 

Instead:  If read_balance in the error case chooses the same drive that just
failed, treat it as a failure and don't retry.

Signed-off-by: NeilBrown <neilb@suse.de>
2009-02-06 15:06:47 +11:00
NeilBrown
4044ba58dd md: don't retry recovery of raid1 that fails due to error on source drive.
If a raid1 has only one working drive and it has a sector which
gives an error on read, then an attempt to recover onto a spare will
fail, but as the single remaining drive is not removed from the
array, the recovery will be immediately re-attempted, resulting
in an infinite recovery loop.

So detect this situation and don't retry recovery once an error
on the lone remaining drive is detected.

Allow recovery to be retried once every time a spare is added
in case the problem wasn't actually a media error.

Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:11 +11:00
NeilBrown
efeb53c0e5 md: Allow md devices to be created by name.
Using sequential numbers to identify md devices is somewhat artificial.
Using names can be a lot more user-friendly.

Also, creating md devices by opening the device special file is a bit
awkward.

So this patch provides a new option for creating and naming devices.

Writing a name such as "md_home" to
    /sys/modules/md_mod/parameters/new_array
will cause an array with that name to be created.  It will appear in
/sys/block/ /proc/partitions and /proc/mdstat as 'md_home'.
It will have an arbitrary minor number allocated.

md devices that a created by an open are destroyed on the last
close when the device is inactive.
For named md devices, they will not be destroyed until the array
is explicitly stopped, either with the STOP_ARRAY ioctl or by
writing 'clear' to /sys/block/md_XXXX/md/array_state.

The name of the array must start 'md_' to avoid conflict with
other devices.

Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:10 +11:00
NeilBrown
d3374825ce md: make devices disappear when they are no longer needed.
Currently md devices, once created, never disappear until the module
is unloaded.  This is essentially because the gendisk holds a
reference to the mddev, and the mddev holds a reference to the
gendisk, this a circular reference.

If we drop the reference from mddev to gendisk, then we need to ensure
that the mddev is destroyed when the gendisk is destroyed.  However it
is not possible to hook into the gendisk destruction process to enable
this.

So we drop the reference from the gendisk to the mddev and destroy the
gendisk when the mddev gets destroyed.  However this has a
complication.
Between the call
   __blkdev_get->get_gendisk->kobj_lookup->md_probe
and the call
   __blkdev_get->md_open

there is no obvious way to hold a reference on the mddev any more, so
unless something is done, it will disappear and gendisk will be
destroyed prematurely.

Also, once we decide to destroy the mddev, there will be an unlockable
moment before the gendisk is unlinked (blk_unregister_region) during
which a new reference to the gendisk can be created.  We need to
ensure that this reference can not be used.  i.e. the ->open must
fail.

So:
 1/  in md_probe we set a flag in the mddev (hold_active) which
     indicates that the array should be treated as active, even
     though there are no references, and no appearance of activity.
     This is cleared by md_release when the device is closed if it
     is no longer needed.
     This ensures that the gendisk will survive between md_probe and
     md_open.

 2/  In md_open we check if the mddev we expect to open matches
     the gendisk that we did open.
     If there is a mismatch we return -ERESTARTSYS and modify
     __blkdev_get to retry from the top in that case.
     In the -ERESTARTSYS sys case we make sure to wait until
     the old gendisk (that we succeeded in opening) is really gone so
     we loop at most once.

Some udev configurations will always open an md device when it first
appears.   If we allow an md device that was just created by an open
to disappear on an immediate close, then this can race with such udev
configurations and result in an infinite loop the device being opened
and closed, then re-open due to the 'ADD' even from the first open,
and then close and so on.
So we make sure an md device, once created by an open, remains active
at least until some md 'ioctl' has been made on it.  This means that
all normal usage of md devices will allow them to disappear promptly
when not needed, but the worst that an incorrect usage will do it
cause an inactive md device to be left in existence (it can easily be
removed).

As an array can be stopped by writing to a sysfs attribute
  echo clear > /sys/block/mdXXX/md/array_state
we need to use scheduled work for deleting the gendisk and other
kobjects.  This allows us to wait for any pending gendisk deletion to
complete by simply calling flush_scheduled_work().



Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:10 +11:00
NeilBrown
a21d15042d md: centralise all freeing of an 'mddev' in 'md_free'
md_free is the .release handler for the md kobj_type.
So it makes sense to release all the objects referenced by
the mddev in there, rather than just prior to calling kobject_put
for what we think is the last time.

Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:09 +11:00
NeilBrown
8b76539823 md: move allocation of ->queue from mddev_find to md_probe
It is more balanced to just do simple initialisation in mddev_find,
which allocates and links a new md device, and leave all the
more sophisticated allocation to md_probe (which calls mddev_find).
md_probe already allocated the gendisk.  It should allocate the
queue too.

Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:08 +11:00
Cheng Renquan
cd2ac9321c md: need another print_sb for mdp_superblock_1
md_print_devices is called in two code path: MD_BUG(...), and md_ioctl
with PRINT_RAID_DEBUG.  it will dump out all in use md devices
information;

However, it wrongly processed two types of superblock in one:

The header file <linux/raid/md_p.h> has defined two types of superblock,
struct mdp_superblock_s (typedefed with mdp_super_t) according to md with
metadata 0.90, and struct mdp_superblock_1 according to md with metadata
1.0 and later,

These two types of superblock are very different,

The md_print_devices code processed them both in mdp_super_t, that would
lead to wrong informaton dump like:

	[ 6742.345877]
	[ 6742.345887] md:	**********************************
	[ 6742.345890] md:	* <COMPLETE RAID STATE PRINTOUT> *
	[ 6742.345892] md:	**********************************
	[ 6742.345896] md1: <ram7><ram6><ram5><ram4>
	[ 6742.345907] md: rdev ram7, SZ:00065472 F:0 S:1 DN:3
	[ 6742.345909] md: rdev superblock:
	[ 6742.345914] md:  SB: (V:0.90.0) ID:<42ef13c7.598c059a.5f9f1645.801e9ee6> CT:4919856d
	[ 6742.345918] md:     L5 S00065472 ND:4 RD:4 md1 LO:2 CS:65536
	[ 6742.345922] md:     UT:4919856d ST:1 AD:4 WD:4 FD:0 SD:0 CSUM:b7992907 E:00000001
	[ 6742.345924]      D  0:  DISK<N:0,(1,8),R:0,S:6>
	[ 6742.345930]      D  1:  DISK<N:1,(1,10),R:1,S:6>
	[ 6742.345933]      D  2:  DISK<N:2,(1,12),R:2,S:6>
	[ 6742.345937]      D  3:  DISK<N:3,(1,14),R:3,S:6>
	[ 6742.345942] md:     THIS:  DISK<N:3,(1,14),R:3,S:6>
	...
	[ 6742.346058] md0: <ram3><ram2><ram1><ram0>
	[ 6742.346067] md: rdev ram3, SZ:00065472 F:0 S:1 DN:3
	[ 6742.346070] md: rdev superblock:
	[ 6742.346073] md:  SB: (V:1.0.0) ID:<369aad81.00000000.00000000.00000000> CT:9a322a9c
	[ 6742.346077] md:     L-1507699579 S976570180 ND:48 RD:0 md0 LO:65536 CS:196610
	[ 6742.346081] md:     UT:00000018 ST:0 AD:131048 WD:0 FD:8 SD:0 CSUM:00000000 E:00000000
	[ 6742.346084]      D  0:  DISK<N:-1,(-1,-1),R:-1,S:-1>
	[ 6742.346089]      D  1:  DISK<N:-1,(-1,-1),R:-1,S:-1>
	[ 6742.346092]      D  2:  DISK<N:-1,(-1,-1),R:-1,S:-1>
	[ 6742.346096]      D  3:  DISK<N:-1,(-1,-1),R:-1,S:-1>
	[ 6742.346102] md:     THIS:  DISK<N:0,(0,0),R:0,S:0>
	...
	[ 6742.346219] md:	**********************************
	[ 6742.346221]

Here md1 is metadata 0.90.0, and md0 is metadata 1.2

After some more code to distinguish these two types of superblock, in this patch,

it will generate dump information like:

	[ 7906.755790]
	[ 7906.755799] md:	**********************************
	[ 7906.755802] md:	* <COMPLETE RAID STATE PRINTOUT> *
	[ 7906.755804] md:	**********************************
	[ 7906.755808] md1: <ram7><ram6><ram5><ram4>
	[ 7906.755819] md: rdev ram7, SZ:00065472 F:0 S:1 DN:3
	[ 7906.755821] md: rdev superblock (MJ:0):
	[ 7906.755826] md:  SB: (V:0.90.0) ID:<3fca7a0d.a612bfed.5f9f1645.801e9ee6> CT:491989f3
	[ 7906.755830] md:     L5 S00065472 ND:4 RD:4 md1 LO:2 CS:65536
	[ 7906.755834] md:     UT:491989f3 ST:1 AD:4 WD:4 FD:0 SD:0 CSUM:00fb52ad E:00000001
	[ 7906.755836]      D  0:  DISK<N:0,(1,8),R:0,S:6>
	[ 7906.755842]      D  1:  DISK<N:1,(1,10),R:1,S:6>
	[ 7906.755845]      D  2:  DISK<N:2,(1,12),R:2,S:6>
	[ 7906.755849]      D  3:  DISK<N:3,(1,14),R:3,S:6>
	[ 7906.755855] md:     THIS:  DISK<N:3,(1,14),R:3,S:6>
	...
	[ 7906.755972] md0: <ram3><ram2><ram1><ram0>
	[ 7906.755981] md: rdev ram3, SZ:00065472 F:0 S:1 DN:3
	[ 7906.755984] md: rdev superblock (MJ:1):
	[ 7906.755989] md:  SB: (V:1) (F:0) Array-ID:<5fbcf158:55aa:5fbe:9a79:1e939880dcbd>
	[ 7906.755990] md:    Name: "DG5:0" CT:1226410480
	[ 7906.755998] md:       L5 SZ130944 RD:4 LO:2 CS:128 DO:24 DS:131048 SO:8 RO:0
	[ 7906.755999] md:     Dev:00000003 UUID: 9194d744:87f7:a448:85f2:7497b84ce30a
	[ 7906.756001] md:       (F:0) UT:1226410480 Events:0 ResyncOffset:-1 CSUM:0dbcd829
	[ 7906.756003] md:         (MaxDev:384)
	...
	[ 7906.756113] md:	**********************************
	[ 7906.756116]

this md0 (metadata 1.2) information dumping is exactly according to struct
mdp_superblock_1.

Signed-off-by: Cheng Renquan <crquan@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Dan Williams <dan.j.williams@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:08 +11:00
Cheng Renquan
159ec1fc06 md: use list_for_each_entry macro directly
The rdev_for_each macro defined in <linux/raid/md_k.h> is identical to
list_for_each_entry_safe, from <linux/list.h>, it should be defined to
use list_for_each_entry_safe, instead of reinventing the wheel.

But some calls to each_entry_safe don't really need a safe version,
just a direct list_for_each_entry is enough, this could save a temp
variable (tmp) in every function that used rdev_for_each.

In this patch, most rdev_for_each loops are replaced by list_for_each_entry,
totally save many tmp vars; and only in the other situations that will call
list_del to delete an entry, the safe version is used.

Signed-off-by: Cheng Renquan <crquan@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:08 +11:00
Andre Noll
ccacc7d2cf md: raid0: make hash_spacing and preshift sector-based.
This patch renames the hash_spacing and preshift members of struct
raid0_private_data to spacing and sector_shift respectively and
changes the semantics as follows:

We always have spacing = 2 * hash_spacing. In case
sizeof(sector_t) > sizeof(u32) we also have sector_shift = preshift + 1
while sector_shift = preshift = 0 otherwise.

Note that the values of nb_zone and zone are unaffected by these changes
because in the sector_div() preceeding the assignement of these two
variables both arguments double.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:08 +11:00
Andre Noll
83838ed878 md: raid0: Represent the size of strip zones in sectors.
This completes the block -> sector conversion of struct strip_zone.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:07 +11:00
Andre Noll
0825b87a7d md: raid0 create_strip_zones(): Add KERN_INFO/KERN_ERR to printk's.
This patch consists only of these trivial changes.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:07 +11:00
Andre Noll
6b8796cc3d md: raid0 create_strip_zones(): Make two local variables sector-based.
current_offset and curr_zone_offset stored the corresponding offsets
as 1K quantities. Rename them to current_start and curr_zone_start
to match the naming of struct strip_zone and store the offsets as
sector counts.

Also, add KERN_INFO to the printk() affected by this change to make
checkpatch happy.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:07 +11:00
Andre Noll
6199d3db0f md: raid0: Represent zone->zone_offset in sectors.
For the same reason as in the previous patch, rename it from zone_offset
to zone_start.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:07 +11:00
Andre Noll
019c4e2f3e md: raid0: Represent device offset in sectors.
Rename zone->dev_offset to zone->dev_start to make sure all users
have been converted.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:06 +11:00
Andre Noll
e0f0686834 md: raid0_make_request(): Replace local variable block by sector.
This change already simplifies the code a bit.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:06 +11:00
Andre Noll
a471200595 md: raid0_make_request(): Remove local variable chunk_size.
We might as well use chunk_sects instead.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:06 +11:00
Andre Noll
1b7fdf8ff7 md: raid0_make_request(): Replace chunksize_bits by chunksect_bits.
As ffz(~(2 * x)) = ffz(~x) + 1, we have

	chunksect_bits = chunksize_bits + 1.

Fixup all users accordingly.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:06 +11:00
NeilBrown
0c3573f19d md: use sysfs_notify_dirent to notify changes to md/sync_action.
There is no compelling need for this, but sysfs_notify_dirent is a
nicer interface and the change is good for consistency.

Signed-off-by: NeilBrown <neilb@suse.de>
2009-01-09 08:31:05 +11:00
NeilBrown
538452700d md: fix bitmap-on-external-file bug.
commit a2ed9615e3
fixed a bug with 'internal' bitmaps, but in the process broke
'in a file' bitmaps.  So they are broken in 2.6.28

This fixes it, and needs to go in 2.6.28-stable.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
2009-01-09 08:31:05 +11:00