Commit Graph

217 Commits

Author SHA1 Message Date
Goldwyn Rodrigues
c40f341f1e md-cluster: Use a small window for resync
Suspending the entire device for resync could take too long. Resync
in small chunks.

cluster's resync window (32M) is maintained in r1conf as
cluster_sync_low and cluster_sync_high and processed in
raid1's sync_request(). If the current resync is outside the cluster
resync window:

1. Set the cluster_sync_low to curr_resync_completed.
2. Check if the sync will fit in the new window, if not issue a
   wait_barrier() and set cluster_sync_low to sector_nr.
3. Set cluster_sync_high to cluster_sync_low + resync_window.
4. Send a message to all nodes so they may add it in their suspension
   list.

bitmap_cond_end_sync is modified to allow to force a sync inorder
to get the curr_resync_completed uptodate with the sector passed.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-10-12 01:32:05 -05:00
Goldwyn Rodrigues
3c462c880b md: Increment version for clustered bitmaps
Add BITMAP_MAJOR_CLUSTERED as 5, in order to prevent older kernels
to assemble a clustered device.

In order to maximize compatibility, the major version is set to
BITMAP_MAJOR_CLUSTERED *only* if the bitmap is clustered.

Added MD_FEATURE_CLUSTERED in order to return error for older
kernels which would assemble MD even if the bitmap is corrupted.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-12 01:31:33 -05:00
NeilBrown
da6fb7a9e5 md/bitmap: don't pass -1 to bitmap_storage_alloc.
Passing -1 to bitmap_storage_alloc() causes page->index to be set to
-1, which is quite problematic.

So only pass ->cluster_slot if mddev_is_clustered().

Fixes: b97e92574c ("Use separate bitmaps for each nodes in the cluster")
Cc: stable@vger.kernel.org (v4.1+)
Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-02 17:24:13 +10:00
Linus Torvalds
aca105a697 Some md fixes for 4.2
Several are tagged for -stable.
 A few aren't because they are not very, serious or
 because they are in the 'experimental' cluster code.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2
 
 iQIcBAABCAAGBQJVsbRgAAoJEDnsnt1WYoG54BcQAJlVxcGdMXNAbFAfhToH+cwY
 DcCKmnXiu3TCcK/gtr0SlUKIhv7kPE2HaGbTko3g5/uTk7SCuMSWRbjpQJr1u98U
 9VUPZV0RGLEcQXgsjG3sobEtdSYMSn1/BpdJpmsn/Q6cyTheiEJA9fEghn9F0Iw9
 3Ctc56aL0nKsnpeRTvWmKR3F995L2Ene+pIHPbSqTlQcGU+DdxQL/iY9YspMzeih
 6SWQICo59+pGSRQdKaU968nZ1a8hJCvhV2NbW0JsJMo9iGo5htCJLdxZatscZV6E
 xAppCRymW/Nl0n59wCOBhUp+0skVhtYZ1UmNdx/vUA7vcZJX85vIG7WGaaSQAmlF
 Y4nNMSaX6SWbt/oVgq+JiD39T1oFZN5N5Fh9juqcp3fshiWLO74cnTwea1LtkQZX
 LfW2HhajDUgoJqoXL6ppKDK8l7alQdcaoYn0C6SfqRZ+PLB5ERrSBHNZpKDbI9aw
 CFW93lHTtlwtwZn0S7k06mCG8ilO4iPthUVaJEeI1kUWVKY0Ju4xnVTt/7jCroUa
 Km14KdWeZsS8j9/xr6FYBjarjuh7M9SoflgUK84txE+PIZsSczyrErpBkMf2YBWQ
 0KduqQabXa1XYWGtZ7Uhj6iOOGNBcTcZsww8cBEDOJEDyCtSs5w/iPmsFCEGUuo2
 YTz6qKpYPgB1VzK2PoBG
 =6ZCK
 -----END PGP SIGNATURE-----

Merge tag 'md/4.2-fixes' of git://neil.brown.name/md

Pull md fixes from Neil Brown:
 "Some md fixes for 4.2

  Several are tagged for -stable.
  A few aren't because they are not very, serious or because they are in
  the 'experimental' cluster code"

* tag 'md/4.2-fixes' of git://neil.brown.name/md:
  md/raid5: clear R5_NeedReplace when no longer needed.
  Fix read-balancing during node failure
  md-cluster: fix bitmap sub-offset in bitmap_read_sb
  md: Return error if request_module fails and returns positive value
  md: Skip cluster setup in case of error while reading bitmap
  md/raid1: fix test for 'was read error from last working device'.
  md: Skip cluster setup for dm-raid
  md: flush ->event_work before stopping array.
  md/raid10: always set reshape_safe when initializing reshape_position.
  md/raid5: avoid races when changing cache size.
2015-07-25 11:24:58 -07:00
Goldwyn Rodrigues
33e38ac688 md-cluster: fix bitmap sub-offset in bitmap_read_sb
bitmap_read_sb is modifying mddev->bitmap_info.offset. This works for
the first bitmap read. However, when multiple bitmaps need to be opened
by the same node, it ends up corrupting the offset. Fix it by using a
local variable.

Also, bitmap_read_sb is not required in bitmap_copy_from_slot since
it is called in bitmap_create. Remove bitmap_read_sb().

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-07-24 13:37:55 +10:00
Goldwyn Rodrigues
f735727319 md: Skip cluster setup in case of error while reading bitmap
If the bitmap read fails, the error code set is -EINVAL. However,
we don't check for errors and go ahead with cluster_setup.
Skip the cluster setup in case of error.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-07-24 13:37:48 +10:00
Goldwyn Rodrigues
d3b178adb3 md: Skip cluster setup for dm-raid
There is a bug that the bitmap superblock isn't initialised properly for
dm-raid, so a new field can have garbage in new fields.
(dm-raid does initialisation in the kernel - md initialised the
 superblock in mdadm).

This means that for dm-raid we cannot currently trust the new ->nodes
field. So:
 - use __GFP_ZERO to initialise the superblock properly for all new
    arrays
 - initialise all fields in bitmap_info in bitmap_new_disk_sb
 - ignore ->nodes for dm arrays (yes, this is a hack)

This bug exposes dm-raid to bug in the (still experimental) md-cluster
code, so it is suitable for -stable.  It does cause crashes.

References: https://bugzilla.kernel.org/show_bug.cgi?id=100491
Cc: stable@vger.kernel.org (v4.1)
Signed-off-By: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.com>
2015-07-23 09:22:00 +10:00
Linus Torvalds
1dc51b8288 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull more vfs updates from Al Viro:
 "Assorted VFS fixes and related cleanups (IMO the most interesting in
  that part are f_path-related things and Eric's descriptor-related
  stuff).  UFS regression fixes (it got broken last cycle).  9P fixes.
  fs-cache series, DAX patches, Jan's file_remove_suid() work"

[ I'd say this is much more than "fixes and related cleanups".  The
  file_table locking rule change by Eric Dumazet is a rather big and
  fundamental update even if the patch isn't huge.   - Linus ]

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits)
  9p: cope with bogus responses from server in p9_client_{read,write}
  p9_client_write(): avoid double p9_free_req()
  9p: forgetting to cancel request on interrupted zero-copy RPC
  dax: bdev_direct_access() may sleep
  block: Add support for DAX reads/writes to block devices
  dax: Use copy_from_iter_nocache
  dax: Add block size note to documentation
  fs/file.c: __fget() and dup2() atomicity rules
  fs/file.c: don't acquire files->file_lock in fd_install()
  fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation
  vfs: avoid creation of inode number 0 in get_next_ino
  namei: make set_root_rcu() return void
  make simple_positive() public
  ufs: use dir_pages instead of ufs_dir_pages()
  pagemap.h: move dir_pages() over there
  remove the pointless include of lglock.h
  fs: cleanup slight list_entry abuse
  xfs: Correctly lock inode when removing suid and file capabilities
  fs: Call security_ops->inode_killpriv on truncate
  fs: Provide function telling whether file_remove_privs() will do anything
  ...
2015-07-04 19:36:06 -07:00
Miklos Szeredi
2726d56620 vfs: add seq_file_path() helper
Turn
	seq_path(..., &file->f_path, ...);
into
	seq_file_path(..., file, ...);

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-06-23 18:01:07 -04:00
Miklos Szeredi
9bf39ab2ad vfs: add file_path() helper
Turn
	d_path(&file->f_path, ...);
into
	file_path(file, ...);

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-06-23 18:00:05 -04:00
NeilBrown
8532e34390 md/bitmap: remove rcu annotation from pointer arithmetic.
Evaluating  "&mddev->disks" is simple pointer arithmetic, so
it does not need 'rcu' annotations - no dereferencing is happening.

Also enhance the comment to explain that 'rdev' in that case
is not actually a pointer to an rdev.

Reported-by: Patrick Marlier <patrick.marlier@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-05-21 09:14:41 +10:00
Goldwyn Rodrigues
97f6cd39da md-cluster: re-add capabilities
When "re-add" is writted to /sys/block/mdXX/md/dev-YYY/state,
the clustered md:

1. Sends RE_ADD message with the desc_nr. Nodes receiving the message
   clear the Faulty bit in their respective rdev->flags.
2. The node initiating re-add, gathers the bitmaps of all nodes
   and copies them into the local bitmap. It does not clear the bitmap
   from which it is copying.
3. Initiating node schedules a md recovery to sync the devices.

Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-04-22 07:59:39 +10:00
Goldwyn Rodrigues
124eb761ed md: Fix bitmap offset calculations
The calculations of bitmap offset is incorrect with respect to bits to bytes
conversion.

Also, remove an irrelevant duplicate message.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-03-25 13:07:55 +11:00
Stephen Rothwell
3b0e6aacbf md/bitmap: use sector_div for sector_t divisions
neilb: modified to not corrupt ->resync_max_sectors.

sector_div usage fixed by Guoqing Jiang <gqjiang@suse.com>

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-03-04 13:08:16 +11:00
NeilBrown
935f3d4fc6 md/bitmap: fix incorrect DIV_ROUND_UP usage.
DIV_ROUTND_UP doesn't work on "long long", - and it should be
sector_t anyway.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-03-04 12:54:29 +11:00
Goldwyn Rodrigues
11dd35daaa Copy set bits from another slot
bitmap_copy_from_slot reads the bitmap from the slot mentioned.
It then copies the set bits to the node local bitmap.

This is helper function for the resync operation on node failure.

bitmap_set_memory_bits() currently assumes it is only run at startup and that
they bitmap is currently empty.  So if it finds that a region is already
marked as dirty, it won't mark it dirty again. Change bitmap_set_memory_bits()
to always set the NEEDED_MASK bit if 'needed' is set.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:59:05 -06:00
Goldwyn Rodrigues
f9209a3235 bitmap_create returns bitmap pointer
This is done to have multiple bitmaps open at the same time.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 09:57:57 -06:00
Goldwyn Rodrigues
b97e92574c Use separate bitmaps for each nodes in the cluster
On-disk format:

0                    4k                     8k                    12k
-------------------------------------------------------------------
| idle                | md super            | bm super [0] + bits |
| bm bits[0, contd]   | bm super[1] + bits  | bm bits[1, contd]   |
| bm super[2] + bits  | bm bits [2, contd]  | bm super[3] + bits  |
| bm bits [3, contd]  |                     |                     |

Bitmap super has a field nodes, which defines the maximum number
of nodes the device can use. While reading the bitmap super, if
the cluster finds out that the number of nodes is > 0:
1. Requests the md-cluster module.
2. Calls md_cluster_ops->join(), which sets up clustering such as
   joining DLM lockspace.

Since the first time, the first bitmap is read. After the call
to the cluster_setup, the bitmap offset is adjusted and the
superblock is re-read. This also ensures the bitmap is read
the bitmap lock (when bitmap lock is introduced in later patches)

Questions:
1. cluster name is repeated in all bitmap supers. Is that okay?

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:30:11 -06:00
Goldwyn Rodrigues
cf921cc19c Add node recovery callbacks
DLM offers callbacks when a node fails and the lock remastery
is performed:

1. recover_prep: called when DLM discovers a node is down
2. recover_slot: called when DLM identifies the node and recovery
		can start
3. recover_done: called when all nodes have completed recover_slot

recover_slot() and recover_done() are also called when the node joins
initially in order to inform the node with its slot number. These slot
numbers start from one, so we deduct one to make it start with zero
which the cluster-md code uses.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:30:11 -06:00
Goldwyn Rodrigues
c4ce867fda Introduce md_cluster_info
md_cluster_info stores the cluster information in the MD device.

The join() is called when mddev detects it is a clustered device.
The main responsibilities are:
	1. Setup a DLM lockspace
	2. Setup all initial locks such as super block locks and bitmap lock (will come later)

The leave() clears up the lockspace and all the locks held.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2015-02-23 07:28:42 -06:00
NeilBrown
b7b17c9b67 md: remove mddev_lock() from md_attr_show()
Most attributes can be read safely without any locking.
A race might lead to a slightly out-dated value, but nothing wrong.

We already have locking in some places where needed.
All that remains is can_clear_show(), behind_writes_used_show()
and action_show() which are easily fixed.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:55 +11:00
NeilBrown
978a7a47ca md/bitmap: protect clearing of ->bitmap by mddev->lock
This makes it safe to inspect the struct while holding only
the spinlock.

Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-06 09:32:55 +11:00
NeilBrown
d959014334 md/bitmap: fix a might_sleep() warning.
commit 8eb23b9f35
    sched: Debug nested sleeps

causes false-positive warnings in RAID5 code.

This annotation removes them and adds a comment
explaining why there is no real problem.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2015-02-02 17:08:03 +11:00
NeilBrown
4b5060ddae md/bitmap: always wait for writes on unplug.
If two threads call bitmap_unplug at the same time, then
one might schedule all the writes, and the other might
decide that it doesn't need to wait.  But really it does.

It rarely hurts to wait when it isn't absolutely necessary,
and the current code doesn't really focus on 'absolutely necessary'
anyway.  So just wait always.

This can potentially lead to data corruption if a crash happens
at an awkward time and data was written before the bitmap was
updated.  It is very unlikely, but this should go to -stable
just to be safe.  Appropriate for any -stable.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@vger.kernel.org (please delay until 3.18 is released)
2014-10-09 10:07:04 +11:00
NeilBrown
f2e06c5884 md/bitmap: remove confusing code from filemap_get_page.
file_page_index(store, 0) is *always* 0.
This is because the bitmap sb, at 256 bytes, is *always* less than
one page.
So subtracting it has no effect and the code should be removed.

Reported-by: Goldwyn Rodrigues <rgoldwyn@suse.de>
Signed-off-by: NeilBrown <neilb@suse.de>
2014-05-29 16:59:47 +10:00
NeilBrown
035328c202 md/bitmap: don't abuse i_writecount for bitmap files.
md bitmap code currently tries to use i_writecount to stop any other
process from writing to out bitmap file.  But that is really an abuse
and has bit-rotted so locking is all wrong.

So discard that - root should be allowed to shoot self in foot.

Still use it in a much less intrusive way to stop the same file being
used as bitmap on two different array, and apply other checks to
ensure the file is at least vaguely usable for bitmap storage
(is regular, is open for write.  Support for ->bmap is already checked
elsewhere).

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NeilBrown <neilb@suse.de>
2014-04-09 12:26:59 +10:00
Tejun Heo
324a56e16e kernfs: s/sysfs_dirent/kernfs_node/ and rename its friends accordingly
kernfs has just been separated out from sysfs and we're already in
full conflict mode.  Nothing can make the situation any worse.  Let's
take the chance to name things properly.

This patch performs the following renames.

* s/sysfs_elem_dir/kernfs_elem_dir/
* s/sysfs_elem_symlink/kernfs_elem_symlink/
* s/sysfs_elem_attr/kernfs_elem_file/
* s/sysfs_dirent/kernfs_node/
* s/sd/kn/ in kernfs proper
* s/parent_sd/parent/
* s/target_sd/target/
* s/dir_sd/parent/
* s/to_sysfs_dirent()/rb_to_kn()/
* misc renames of local vars when they conflict with the above

Because md, mic and gpio dig into sysfs details, this patch ends up
modifying them.  All are sysfs_dirent renames and trivial.  While we
can avoid these by introducing a dummy wrapping struct sysfs_dirent
around kernfs_node, given the limited usage outside kernfs and sysfs
proper, I don't think such workaround is called for.

This patch is strictly rename only and doesn't introduce any
functional difference.

- mic / gpio renames were missing.  Spotted by kbuild test robot.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-11 15:28:36 -08:00
Tejun Heo
388975ccca sysfs: clean up sysfs_get_dirent()
The pre-existing sysfs interfaces which take explicit namespace
argument are weird in that they place the optional @ns in front of
@name which is contrary to the established convention.  For example,
we end up forcing vast majority of sysfs_get_dirent() users to do
sysfs_get_dirent(parent, NULL, name), which is silly and error-prone
especially as @ns and @name may be interchanged without causing
compilation warning.

This renames sysfs_get_dirent() to sysfs_get_dirent_ns() and swap the
positions of @name and @ns, and sysfs_get_dirent() is now a wrapper
around sysfs_get_dirent_ns().  This makes confusions a lot less
likely.

There are other interfaces which take @ns before @name.  They'll be
updated by following patches.

This patch doesn't introduce any functional changes.

v2: EXPORT_SYMBOL_GPL() wasn't updated leading to undefined symbol
    error on module builds.  Reported by build test robot.  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-09-26 15:33:18 -07:00
Jingoo Han
b29bebd66d md: replace strict_strto*() with kstrto*()
The usage of strict_strtoul() is not preferred, because
strict_strtoul() is obsolete. Thus, kstrtoul() should be
used.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2013-06-14 08:10:26 +10:00
Akinobu Mita
3f810b6c4a md: use set_bit_le and clear_bit_le
The value returned by test_and_set_bit_le() drivers/md/bitmap.c is not used.
So just use set_bit_le(). The same goes for test_and_clear_bit_le().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
2013-04-24 11:42:41 +10:00
Al Viro
496ad9aa8e new helper: file_inode(file)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-22 23:31:31 -05:00
Jianpeng Ma
582e2e056a md/bitmap:Don't use IS_ERR to judge alloc_page().
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2012-10-11 13:45:36 +11:00
Michael Wang
fd177481b4 raid: replace list_for_each_continue_rcu with new interface
This patch replaces list_for_each_continue_rcu() with
list_for_each_entry_continue_rcu() to save a few lines
of code and allow removing list_for_each_continue_rcu().

Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2012-10-11 13:43:21 +11:00
NeilBrown
f54a9d0e59 md/raid1: submit IO from originating thread instead of md thread.
queuing writes to the md thread means that all requests go through the
one processor which may not be able to keep up with very high request
rates.

So use the plugging infrastructure to submit all requests on unplug.
If a 'schedule' is needed, we fall back on the old approach of handing
the requests to the thread for it to handle.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-08-02 08:33:20 +10:00
NeilBrown
1dff2b87a3 md/bitmap: record the space available for the bitmap in the superblock.
Now that bitmaps can grow and shrink it is best if we record
how much space is available.  This means that when
we reduce the size of the bitmap we won't "lose" the space
for late when we might want to increase the size of the bitmap
again.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:34 +10:00
NeilBrown
b81a040481 md/bitmap: make sure reshape request are reflected in superblock.
As a reshape may change the sync_size and/or chunk_size, we need
to update these whenever we write out the bitmap superblock.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:26 +10:00
NeilBrown
d60b479d17 md/bitmap: add bitmap_resize function to allow bitmap resizing.
This function will allocate the new data structures and copy
bits across from old to new, allowing for the possibility that the
chunksize has changed.

Use the same function for performing the initial allocation
of the structures.  This improves test coverage.

When bitmap_resize is used to resize an existing bitmap, it
only copies '1' bits in, not '0' bits.
So when allocating the bitmap, ensure everything is initialised
to ZERO.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:25 +10:00
NeilBrown
15702d7fb6 md/bitmap: use DIV_ROUND_UP instead of open-code
Also take the opportunity to simplify CHUNK_BLOCK_RATIO.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:25 +10:00
NeilBrown
40cffcc0e8 md/bitmap: create a 'struct bitmap_counts' substructure of 'struct bitmap'
The new "struct bitmap_counts" contains all the fields that are
related to counting the number of active writes in each bitmap chunk.

Having this separate will make it easier to change the chunksize
or overall size of a bitmap atomically.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:24 +10:00
NeilBrown
63c68268b2 md/bitmap: make bitmap bitops atomic.
This allows us to remove spinlock protection which is
more heavy-weight than simple atomics.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:23 +10:00
NeilBrown
bdfd114073 md/bitmap: make _page_attr bitops atomic.
Using e.g. set_bit instead of __set_bit and using test_and_clear_bit
allow us to remove some locking and contract other locked ranges.

It is rare that we set or clear a lot of these bits, so gain should
outweigh any cost.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:22 +10:00
NeilBrown
fae7d326cd md/bitmap: merge bitmap_file_unmap and bitmap_file_put.
There functions really do one thing together: release the
'bitmap_storage'.  So make them just one function.

Since we removed the locking (previous patch), we don't need to zero
any fields before freeing them, so it all becomes a bit simpler.


Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:21 +10:00
NeilBrown
62f82faace md/bitmap: remove async freeing of bitmap file.
There is no real value in freeing things the moment there is an error.
It is just as good to free the bitmap file and pages when the bitmap
is explicitly removed (and replaced?) or at shutdown.

With this gone, the bitmap will only disappear when the array is
quiescent, so we can remove some locking.

As the 'filemap' doesn't disappear now, include extra checks before
trying to write any of it out.
Also remove the check for "has it disappeared" in
bitmap_daemon_write().


Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:21 +10:00
NeilBrown
7466712347 md/bitmap: convert some spin_lock_irqsave to spin_lock_irq
All of these sites can only be called from process context with
irqs enabled, so using irqsave/irqrestore just adds noise.
Remove it.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:19 +10:00
NeilBrown
b405fe91e5 md/bitmap: use set_bit, test_bit, etc for operation on bitmap->flags.
We currently use '&' and '|' which isn't the norm in the kernel
and doesn't allow easy atomicity.
So change to bit numbers and {set,clear,test}_bit.
This allows us to remove a spinlock/unlock (which was dubious anyway)
and some other simplifications.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:15 +10:00
NeilBrown
84e923453e md/bitmap: remove single-bit manipulation on sb->state
Just do single-bit manipulations on bitmap->flags and copy whole
value between that and sb->state.

This will allow next patch which changes how bit manipulations are
performed on bitmap->flags.

This does result in BITMAP_STALE not being set in sb by
bitmap_read_sb, however as the setting is determined by other
information in the 'sb' we do not lose information this way.
Normally, bitmap_load will be called shortly which will clear
BITMAP_STALE anyway.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:14 +10:00
NeilBrown
edbb79df67 md/bitmap: remove bitmap_mask_state
This function isn't really needed.  It sets or clears a flag in both
bitmap->flags and sb->state.
However both times it is called, bitmap_update_sb is called soon
afterwards which copies bitmap->flags to sb->state.
So just make changes to bitmap->flags, and open-code those rather than
hiding in a function.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:13 +10:00
NeilBrown
bc9891a885 md/bitmap: move storage allocation from bitmap_load to bitmap_create.
We should allocate memory for the storage-bitmap at create-time, not
load time.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:12 +10:00
NeilBrown
d1244cb062 md/bitmap: separate bitmap file allocation to its own function.
This will allow allocation before swapping in a new bitmap.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:12 +10:00
NeilBrown
9b1215c102 md/bitmap: store bytes in file rather than just in last page.
This number is more generally useful, and bytes-in-last-page is
easily extracted from it.

Signed-off-by: NeilBrown <neilb@suse.de>
2012-05-22 13:55:11 +10:00