md supports multiple different RAID level, each being implemented by a
'personality' (which is often in a separate module).
These personalities have fairly artificial 'numbers'. The numbers
are use to:
1- provide an index into an array where the various personalities
are recorded
2- identify the module (via an alias) which implements are particular
personality.
Neither of these uses really justify the existence of personality numbers.
The array can be replaced by a linked list which is searched (array lookup
only happens very rarely). Module identification can be done using an alias
based on level rather than 'personality' number.
The current 'raid5' modules support two level (4 and 5) but only one
personality. This slight awkwardness (which was handled in the mapping from
level to personality) can be better handled by allowing raid5 to register 2
personalities.
With this change in place, the core md module does not need to have an
exhaustive list of all possible personalities, so other personalities can be
added independently.
This patch also moves the check for chunksize being non-zero into the ->run
routines for the personalities that need it, rather than having it in core-md.
This has a side effect of allowing 'faulty' and 'linear' not to have a
chunk-size set.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- replace open-coded hash chain with hlist macros
- Fix hash-table size at one page - it is already quite generous, so there
will never be a need to use multiple pages, so no need for __get_free_pages
No functional change.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Replace multiple kmalloc/memset pairs with kzalloc calls.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Substitute:
page_cache_get -> get_page
page_cache_release -> put_page
PAGE_CACHE_SHIFT -> PAGE_SHIFT
PAGE_CACHE_SIZE -> PAGE_SIZE
PAGE_CACHE_MASK -> PAGE_MASK
__free_page -> put_page
because we aren't using the page cache, we are just using pages.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There is this "FIXME" comment with a typo in it!! that been annoying me for
days, so I just had to remove it.
conf->disks[i].rdev should only be accessed if
- we know we hold a reference or
- the mddev->reconfig_sem is down or
- we have a rcu_readlock
handle_stripe was referencing rdev in three places without any of these. For
the first two, get an rcu_readlock. For the last, the same access
(md_sync_acct call) is made a little later after the rdev has been claimed
under and rcu_readlock, if R5_Syncio is set. So just use that access...
However R5_Syncio isn't really needed as the 'syncing' variable contains the
same information. So use that instead.
Issues, comment, and fix are identical in raid5 and raid6.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is important because bitmap_create uses
mddev->resync_max_sectors
and that doesn't have a valid value until after the array
has been initialised (with pers->run()).
[It doesn't make a difference for current personalities that
support bitmaps, but will make a difference for raid10]
This has the added advantage of meaning with can move the thread->timeout
manipulation inside the bitmap.c code instead of sprinkling identical code
throughout all personalities.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
See patch to md.txt for more details
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Resync code:
A test that isn't needed,
a 'compute_block' that makes more sense
elsewhere (And then doesn't need a test),
a couple of BUG_ONs to confirm the change makes sense.
Printks:
A few were missing KERN_*
Also fix a typo in a comment..
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The raid5 stripe cache was recently changed from fixed size (NR_STRIPES) to
variable size (conf->max_nr_stripes). However there are two places that still
use the constant and as a result, reducing the size of the stripe cache can
result in a deadlock.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
bitmap_unplug actually writes data (bits) to storage, so we shouldn't be
holding a spinlock...
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1/ I really should be using the __ATTR macros for defining attributes, so
that the .owner field get set properly, otherwise modules can be removed
while sysfs files are open. This also involves some name changes of _show
routines.
2/ Always lock the mddev (against reconfiguration) for all sysfs attribute
access. This easily avoid certain races and is completely consistant with
other interfaces (ioctl and /proc/mdstat both always lock against
reconfiguration).
3/ raid5 attributes must check that the 'conf' structure actually exists
(the array could have been stopped while an attribute file was open).
4/ A missing 'kfree' from when the raid5_conf_t was converted to have a
kobject embedded, and then converted back again.
Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A sync of raid5 usually ignore blocks which the bitmap says are in-sync. But
a user-request check or repair should not ignore these.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This has the advantage of removing the confusion caused by 'rdev_t' and
'mddev_t' both having 'in_sync' fields.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Two refinements to the 'attempt-overwrite-on-read-error' mechanism.
1/ If the array is read-only, don't attempt an over-write.
2/ If there are more than max_nr_stripes read errors on a device with
no success, fail the drive. This will make sure a dead
drive will be eventually kicked even when we aren't trying
to rewrite (which would normally kick a dead drive more quickly.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There isn't really a need for raid5 attributes to be an a subdirectory,
so this patch moves them from
/sys/block/mdX/md/raid5/attribute
to
/sys/block/mdX/md/attribute
This suggests that all md personalities should co-operate about
namespace usage, but that shouldn't be a problem.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
With this, raid5 can be asked to check parity without repairing it. It also
keeps a count of the number of incorrect parity blocks found (mismatches) and
reports them through sysfs.
Signed-off-by: Neil Brown <neilb@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
/sys/block/mdX/md/raid5/
contains raid5-related attributes.
Currently
stripe_cache_size
is number of entries in stripe cache, and is settable.
stripe_cache_active
is number of active entries, and in only readable.
Signed-off-by: Neil Brown <neilb@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch changes the behaviour of raid5 when it gets a read error.
Instead of just failing the device, it tried to find out what should have
been there, and writes it over the bad block. For some media-errors, this
has a reasonable chance of fixing the error. If the write succeeds, and a
subsequent read succeeds as well, raid5 decided the address is OK and
conitnues.
Instead of failing a drive on read-error, we attempt to re-write the block,
and then re-read. If that all works, we allow the device to remain in the
array.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use schedule_timeout_interruptible() instead of
set_current_state()/schedule_timeout() to reduce kernel size.
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Instead of having ->read_sectors and ->write_sectors, combine the two
into ->sectors[2] and similar for the other fields. This saves a branch
several places in the io path, since we don't have to care for what the
actual io direction is. On my x86-64 box, that's 200 bytes less text in
just the core (not counting the various drivers).
Signed-off-by: Jens Axboe <axboe@suse.de>
Most awkward part of this is delaying write requests until bitmap updates have
been flushed.
To achieve this, we have a sequence number (seq_flush) which is incremented
each time the raid5 is unplugged.
If the raid thread notices that this has changed, it flushes bitmap changes,
and assigned the value of seq_flush to seq_write.
When a write request arrives, it is given the number from seq_write, and that
write request may not complete until seq_flush is larger than the saved seq
number.
We have a new queue for storing stripes which are waiting for a bitmap flush
and an extra flag for stripes to record if the write was 'degraded' and so
should not clear the a bit in the bitmap.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
md does not yet support BIO_RW_BARRIER, so be honest about it and fail
(-EOPNOTSUPP) any such requests.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The default resync_max_sector is set to "mddev->size << 1". If the
raid-personality-module updates mddev->size, it must update
resync_max_sectors too.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Without this, and attempt to 'grow' an array will claim to have synced the
extra part without actually having done anything.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Before completing a 'write' the md superblock might need to be updated.
This is best done by the md_thread.
The current code schedules this up and queues the write request for later
handling by the md_thread.
However some personalities (Raid5/raid6) will deadlock if the md_thread
tries to submit requests to its own array.
So this patch changes things so the processes submitting the request waits
for the superblock to be written and then submits the request itself.
This fixes a recently-created deadlock in raid5/raid6
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1/ change the return value (which is number-of-sectors synced)
from 'int' to 'sector_t'.
The number of sectors is usually easily small enough to fit
in an int, but if resync needs to abort, it may want to return
the total number of remaining sectors, which could be large.
Also errors cannot be returned as negative numbers now, so use
0 instead
2/ Add a 'skipped' return parameter to allow the array to report
that it skipped the sectors. This allows md to take this into account
in the speed calculations.
Currently there is no important skipping, but the bitmap-based-resync
that is coming will use this.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When md marks the superblock dirty before a write, it calls
generic_make_request (to write the superblock) from within
generic_make_request (to write the first dirty block), which could cause
problems later.
With this patch, the superblock write is always done by the helper thread, and
write request are delayed until that write completes.
Also, the locking around marking the array dirty and writing the superblock is
improved to avoid possible races.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
md_enter_safemode checks if it is time to mark the md superblock as 'clean'.
i.e. if all writes have completed and a suitable delay has passed.
This is currently called from md_handle_safemode which in-turn is called
(almost) every time md_check_recovery is called, and from the end of
md_do_sync which causes the mddev->thread to run, which will always call
md_check_recovery as well.
So it doesn't need to be a separate function and fits quite well into
md_check_recovery.
The "almost" is because multipathd calls md_check_recovery but not
md_handle_safemode. This is OK because the code from md_enter_safemode is a
no-op if mddev->safemode == 0, which it always is for a multipathd (providing
we don't allow it to be set to 2 on a signal...)
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We we set the too early, they may still be in place and possibly get called
even though the array didn't get set up properly.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch changes calls to synchronize_kernel(), deprecated in the earlier
"Deprecate synchronize_kernel, GPL replacement" patch to instead call the new
synchronize_rcu() and synchronize_sched() APIs.
Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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!
NeilBrown