raid0_make_request() should use a private bio_set rather than the
shared fs_bio_set, which is only meant for filesystems to use.

raid0_make_request() shouldn't loop around using the bio_set
multiple times as that can deadlock.

So use mddev->bio_set and pass the tail to generic_make_request()
instead of looping on it.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

Copy & paste from the REQ_OP_WRITE_SAME code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Include information about PPL location and size into mdp_superblock_1
and copy it to/from rdev. Because PPL is mutually exclusive with bitmap,
put it in place of 'bitmap_offset'. Add a new flag MD_FEATURE_PPL for
'feature_map', analogically to MD_FEATURE_BITMAP_OFFSET. Add MD_HAS_PPL
to mddev->flags to indicate that PPL is enabled on an array.
Signed-off-by: NArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: NShaohua Li <shli@fb.com>

This makes md do the same thing as dm for write same IO failure. Please
see 7eee4ae2(dm: disable WRITE SAME if it fails) for details why we need
this.

We did a little bit different than dm. Instead of disabling writesame in
the first IO error, we disable it till next writesame IO coming after
the first IO error. This way we don't need to clone a bio.

Also reported here: https://bugzilla.kernel.org/show_bug.cgi?id=118581Suggested-by: NNeilBrown <neilb@suse.com>
Acked-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

We will want to have struct backing_dev_info allocated separately from
struct request_queue. As the first step add pointer to backing_dev_info
to request_queue and convert all users touching it. No functional
changes in this patch.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

Commit 6995f0b2 (md: takeover should clear unrelated bits) clear
unrelated bits, but it's quite fragile. To avoid error in the future,
define a macro for unsupported mddev flags for each raid type and use it
to clear unsupported mddev flags. This should be less error-prone.
Suggested-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

When we change level from raid1 to raid5, the MD_FAILFAST_SUPPORTED bit
will be accidentally set, but raid5 doesn't support it. The same is true
for the MD_HAS_JOURNAL bit.

Fix: 46533ff7 (md: Use REQ_FAILFAST_* on metadata writes where appropriate)
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

The block tracing infrastructure (accessed with blktrace/blkparse)
supports the tracing of mapping bios from one device to another.
This is currently used when a bio in a partition is mapped to the
whole device, when bios are mapped by dm, and for mapping in md/raid5.
Other md personalities do not include this tracing yet, so add it.

When a read-error is detected we redirect the request to a different device.
This could justifiably be seen as a new mapping for the originial bio,
or a secondary mapping for the bio that errors.  This patch uses
the second option.

When md is used under dm-raid, the mappings are not traced as we do
not have access to the block device number of the parent.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

This makes md/raid0 much less verbose as the messages about
the array geometry are now pr_debug()
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

Since commit 63a4cc24, bio->bi_rw contains flags in the lower
portion and the op code in the higher portions. This means that
old code that relies on manually setting bi_rw is most likely
going to be broken. Instead of letting that brokeness linger,
rename the member, to force old and out-of-tree code to break
at compile time instead of at runtime.

No intended functional changes in this commit.
Signed-off-by: NJens Axboe <axboe@fb.com>

To avoid confusion between REQ_OP_FLUSH, which is handled by
request_fn drivers, and upper layers requesting the block layer
perform a flush sequence along with possibly a WRITE, this patch
renames REQ_FLUSH to REQ_PREFLUSH.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Separate the op from the rq_flag_bits and have md
set/get the bio using bio_set_op_attrs/bio_op.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Remove the final printk. All preceding output is already properly
newline-terminated and the printk isn't even KERN_CONT to begin with,
so it only adds one empty line to the log.
Signed-off-by: NMichal Pecio <michal.pecio@gmail.com>
Signed-off-by: NShaohua Li <shli@fb.com>

If this function fails the callers expect that *private_conf is set to
an ERR_PTR() but that isn't true for the first error path where we can't
allocate "conf".  It leads to some uninitialized variable bugs.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NShaohua Li <shli@fb.com>

This patch fix multiple spelling typos found in
various part of kernel.
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Calling e.g. blk_queue_max_hw_sectors() after calls to
disk_stack_limits() discards the settings determined by
disk_stack_limits().
So we need to make those calls first.

Fixes: 199dc6ed ("md/raid0: update queue parameter in a safer location.")
Cc: stable@vger.kernel.org (v2.6.35+ - please apply with 199dc6ed).
Reported-by: NJes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NNeilBrown <neilb@suse.com>

As generic_make_request() is now able to handle arbitrarily sized bios,
it's no longer necessary for each individual block driver to define its
own ->merge_bvec_fn() callback. Remove every invocation completely.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: drbd-user@lists.linbit.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@kernel.org>
Cc: ceph-devel@vger.kernel.org
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: NeilBrown <neilb@suse.de> (for the 'md' bits)
Acked-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NKent Overstreet <kent.overstreet@gmail.com>
[dpark: also remove ->merge_bvec_fn() in dm-thin as well as
 dm-era-target, and resolve merge conflicts]
Signed-off-by: NDongsu Park <dpark@posteo.net>
Signed-off-by: NMing Lin <ming.l@ssi.samsung.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

When a (e.g.) RAID5 array is reshaped to RAID0, the updating
of queue parameters (e.g. max number of sectors per bio) is
done in the wrong place.
It should be part of ->run, but it is actually part of ->takeover.
This means it happens before level_store() calls:

	blk_set_stacking_limits(&mddev->queue->limits);

and so it ineffective.  This can lead to errors from underlying
devices.

So move all the relevant settings out of create_stripe_zones()
and into raid0_run().

As this can lead to a bug-on it is suitable for any -stable
kernel which supports reshape to RAID0.  So 2.6.35 or later.
As the bug has been present for five years there is no urgency,
so no need to rush into -stable.

Fixes: 9af204cf ("md: Add support for Raid5->Raid0 and Raid10->Raid0 takeover")
Cc: stable@vger.kernel.org (v2.6.35+ - please delay until after -final release).
Reported-by: NYi Zhang <yizhan@redhat.com>
Signed-off-by: NNeilBrown <neilb@suse.com>

Currently we have two different ways to signal an I/O error on a BIO:

 (1) by clearing the BIO_UPTODATE flag
 (2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario.  Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

The variable "sector" in "raid0_make_request()" was improperly updated
by a call to "sector_div()" which modifies its first argument in place.
Commit 47d68979 restored this variable
after the call for later re-use.  Unfortunetly the restore was done after
the referenced variable "bio" was advanced.  This lead to the original
value and the restored value being different.  Here we move this line to
the proper place.

One observed side effect of this bug was discarding a file though
unlinking would cause an unrelated file's contents to be discarded.
Signed-off-by: NNeilBrown <neilb@suse.de>
Fixes: 47d68979 ("md/raid0: fix bug with chunksize not a power of 2.")
Cc: stable@vger.kernel.org (any that received above backport)
URL: https://bugzilla.kernel.org/show_bug.cgi?id=98501

This patch is a prerequisite for dm-raid "raid0" support to allow
dm-raid to access the MD RAID0 personality doing unconditional
accesses to mddev->queue, which is NULL in case of dm-raid stacked on
top of MD.

Most of the conditional mddev->queue accesses made it to upstream but
this missing one, which prohibits md raid0 to set disk stack limits
(being done in dm core in case of md underneath dm).
Signed-off-by: NHeinz Mauelshagen <heinzm@redhat.com>
Tested-by: NHeinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

md raid0: access mddev->queue (request queue member) conditionally because it is not set when accessed from dm-raid

The patch makes 3 references to mddev->queue in the raid0 personality
conditional in order to allow for it to be accessed from dm-raid.
Mandatory, because md instances underneath dm-raid don't manage
a request queue of their own which'd lead to oopses without the patch.
Signed-off-by: NHeinz Mauelshagen <heinzm@redhat.com>
Tested-by: NHeinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

Since commit 20d0189b
in v3.14-rc1 RAID0 has performed incorrect calculations
when the chunksize is not a power of 2.

This happens because "sector_div()" modifies its first argument, but
this wasn't taken into account in the patch.

So restore that first arg before re-using the variable.
Reported-by: NJoe Landman <joe.landman@gmail.com>
Reported-by: NDave Chinner <david@fromorbit.com>
Fixes: 20d0189b
Cc: stable@vger.kernel.org (3.14 and later).
Signed-off-by: NNeilBrown <neilb@suse.de>

If ->run() fails, it can either free the data structures it
allocated, or leave that task to ->free() which will be called
on failures.

However:
  md.c calls ->free() even if ->private_data is NULL, which
     causes problems in some personalities.
  raid0.c frees the data, but doesn't clear ->private_data,
     which will become a problem when we fix md.c

So better fix both these issues at once.
Reported-by: NRichard W.M. Jones <rjones@redhat.com>
Fixes: 5aa61f42
URL: https://bugzilla.kernel.org/show_bug.cgi?id=94381Signed-off-by: NNeilBrown <neilb@suse.de>

Now that the ->stop function only frees the private data,
rename is accordingly.

Also pass in the private pointer as an arg rather than using
mddev->private.  This flexibility will be useful in level_store().

Finally, don't clear ->private.  It doesn't make sense to clear
it seeing that isn't what we free, and it is no longer necessary
to clear ->private (it was some time ago before  ->to_remove was
introduced).

Setting ->to_remove in ->free() is a bit of a wart, but not a
big problem at the moment.
Signed-off-by: NNeilBrown <neilb@suse.de>

Each md personality has a 'stop' operation which does two
things:
 1/ it finalizes some aspects of the array to ensure nothing
    is accessing the ->private data
 2/ it frees the ->private data.

All the steps in '1' can apply to all arrays and so can be
performed in common code.

This is useful as in the case where we change the personality which
manages an array (in level_store()), it would be helpful to do
step 1 early, and step 2 later.

So split the 'step 1' functionality out into a new mddev_detach().
Signed-off-by: NNeilBrown <neilb@suse.de>

There is no locking around calls to merge_bvec_fn(), so
it is possible that calls which coincide with a level (or personality)
change could go wrong.

So create a central dispatch point for these functions and use
rcu_read_lock().
If the array is suspended, reject any merge that can be rejected.
If not, we know it is safe to call the function.
Signed-off-by: NNeilBrown <neilb@suse.de>

There is currently no locking around calls to the 'congested'
bdi function.  If called at an awkward time while an array is
being converted from one level (or personality) to another, there
is a tiny chance of running code in an unreferenced module etc.

So add a 'congested' function to the md_personality operations
structure, and call it with appropriate locking from a central
'mddev_congested'.

When the array personality is changing the array will be 'suspended'
so no IO is processed.
If mddev_congested detects this, it simply reports that the
array is congested, which is a safe guess.
As mddev_suspend calls synchronize_rcu(), mddev_congested can
avoid races by included the whole call inside an rcu_read_lock()
region.
This require that the congested functions for all subordinate devices
can be run under rcu_lock.  Fortunately this is the case.
Signed-off-by: NNeilBrown <neilb@suse.de>

My editor shows much of this is RED.
Signed-off-by: NNeilBrown <neilb@suse.de>

If an array has a bitmap, then it cannot be converted to raid0.
Reported-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

The new bio_split() can split arbitrary bios - it's not restricted to
single page bios, like the old bio_split() (previously renamed to
bio_pair_split()). It also has different semantics - it doesn't allocate
a struct bio_pair, leaving it up to the caller to handle completions.

Then convert the existing bio_pair_split() users to the new bio_split()
- and also nvme, which was open coding bio splitting.

(We have to take that BUG_ON() out of bio_integrity_trim() because this
bio_split() needs to use it, and there's no reason it has to be used on
bios marked as cloned; BIO_CLONED doesn't seem to have clearly
documented semantics anyways.)
Signed-off-by: NKent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Neil Brown <neilb@suse.de>

This is prep work for introducing a more general bio_split().
Signed-off-by: NKent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: NeilBrown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Peter Osterlund <petero2@telia.com>
Cc: Sage Weil <sage@inktank.com>

When we start sharing biovecs, keeping bi_vcnt accurate for splits is
going to be error prone - and unnecessary, if we refactor some code.

So bio_segments() has to go - but most of the existing users just needed
to know if the bio had multiple segments, which is easier - add a
bio_multiple_segments() for them.

(Two of the current uses of bio_segments() are going to go away in a
couple patches, but the current implementation of bio_segments() is
unsafe as soon as we start doing driver conversions for immutable
biovecs - so implement a dumb version for bisectability, it'll go away
in a couple patches)
Signed-off-by: NKent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Neil Brown <neilb@suse.de>
Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com>
Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>

Immutable biovecs are going to require an explicit iterator. To
implement immutable bvecs, a later patch is going to add a bi_bvec_done
member to this struct; for now, this patch effectively just renames
things.
Signed-off-by: NKent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@inktank.com>
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Benny Halevy <bhalevy@tonian.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Ben Myers <bpm@sgi.com>
Cc: xfs@oss.sgi.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchand@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Peng Tao <tao.peng@emc.com>
Cc: Andy Adamson <andros@netapp.com>
Cc: fanchaoting <fanchaoting@cn.fujitsu.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Pankaj Kumar <pankaj.km@samsung.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Mel Gorman <mgorman@suse.de>6

RAID5 uses a 'per-array' value for the 'size' of each device.
RAID0 uses a 'per-device' value - it can be different for each device.

When converting a RAID5 to a RAID0 we must ensure that the per-device
size of each device matches the per-array size for the RAID5, else
the array will change size.

If the metadata cannot record a changed per-device size (as is the
case with v0.90 metadata) the array could get bigger on restart.  This
does not cause data corruption, so it not a big issue and is mainly
yet another a reason to not use 0.90.
Signed-off-by: NNeilBrown <neilb@suse.de>

In the current code bio_split() won't be seeing partially completed bios
so this doesn't change any behaviour, but this makes the code a bit
clearer as to what bio_split() actually requires.

The immediate purpose of the patch is removing unnecessary bi_idx
references, but the end goal is to allow partial completed bios to be
submitted, which along with immutable biovecs enables effecient bio
splitting.

Some of the callers were (double) checking that bios could be split, so
update their checks too.
Signed-off-by: NKent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Lars Ellenberg <drbd-dev@lists.linbit.com>
CC: Neil Brown <neilb@suse.de>
CC: Martin K. Petersen <martin.petersen@oracle.com>

Bunch of places in the code weren't using it where they could be -
this'll reduce the size of the patch that puts bi_sector/bi_size/bi_idx
into a struct bvec_iter.
Signed-off-by: NKent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: "Ed L. Cashin" <ecashin@coraid.com>
CC: Nick Piggin <npiggin@kernel.dk>
CC: Jiri Kosina <jkosina@suse.cz>
CC: Jim Paris <jim@jtan.com>
CC: Geoff Levand <geoff@infradead.org>
CC: Alasdair Kergon <agk@redhat.com>
CC: dm-devel@redhat.com
CC: Neil Brown <neilb@suse.de>
CC: Steven Rostedt <rostedt@goodmis.org>
Acked-by: NEd Cashin <ecashin@coraid.com>

Mentioning "bad disk number -1" exposes irrelevant internal detail.
Just say they are inactive and must be removed.
Signed-off-by: NNeilBrown <neilb@suse.de>

Create_stripe_zones returns an error slightly differently to
raid0_run and to raid0_takeover_*.

The error returned used by the second was wrong and an error would
result in mddev->private being set to NULL and sooner or later a
crash.

So never return NULL, return ERR_PTR(err), not NULL from
create_stripe_zones.

This bug has been present since 2.6.35 so the fix is suitable
for any kernel since then.

Cc: stable@vger.kernel.org
Signed-off-by: NNeilBrown <neilb@suse.de>

You cannot resize a RAID0 array (in terms of making the devices
bigger), but the code doesn't entirely stop you.
So:

 disable setting of the available size on each device for
 RAID0 and Linear devices.  This must not change as doing so
 can change the effective layout of data.

 Make sure that the size that raid0_size() reports is accurate,
 but rounding devices sizes to chunk sizes.  As the device sizes
 cannot change now, this isn't so important, but it is best to be
 safe.

Without this change:
  mdadm --grow /dev/md0 -z max
  mdadm --grow /dev/md0 -Z max
  then read to the end of the array

can cause a BUG in a RAID0 array.

These bugs have been present ever since it became possible
to resize any device, which is a long time.  So the fix is
suitable for any -stable kerenl.

Cc: stable@vger.kernel.org
Signed-off-by: NNeilBrown <neilb@suse.de>