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>
This new 'struct bitmap_storage' reflects the external storage of the
bitmap.
Having this clearly defined will make it easier to change the storage
used while the array is active.
Signed-off-by: NeilBrown <neilb@suse.de>
Most often we have the page number, not the page. And that is what
the *_page_attr() functions really want. So change the arguments to
take that number.
Signed-off-by: NeilBrown <neilb@suse.de>
Instead of allocating pages in read_sb_page, read_page and
bitmap_read_sb, allocate them all in bitmap_init_from disk.
Also replace the hack of calling "attach_page_buffers(page, NULL)" to
ensure that free_buffer() won't complain, by putting a test for
PagePrivate in free_buffer().
Signed-off-by: NeilBrown <neilb@suse.de>
An md bitmap comprises two parts
- internal counting of active writes per 'chunk'.
- external storage of whether there are any active writes on
each chunk
The second requires the first, but the first doesn't require the
second.
Not having backing storage means that the bitmap cannot expedite
resync after a crash, but it still allows us to expedite the recovery
of a recently-removed device.
So: allow a bitmap to exist even if there is no backing device.
In that case we default to 128M chunks.
A particular value of this is that we can remove and re-add a bitmap
(possibly of a different granularity) on a degraded array, and not
lose the information needed to fast-recover the missing device.
We don't actually activate these bitmaps yet - that will come
in a later patch.
Signed-off-by: NeilBrown <neilb@suse.de>
If we are to allow bitmaps to be resized when the array is resized,
we need to know how much space there is.
So create an attribute to store this information and set appropriate
defaults.
It can be set more precisely via sysfs, or future metadata extensions
may allow it to be recorded.
Signed-off-by: NeilBrown <neilb@suse.de>
There are two different 'pending' concepts in the handling of the
write intent bitmap.
Firstly, a 'page' from the bitmap (which container PAGE_SIZE*8 bits)
may have changes (bits cleared) that should be written in due course.
There is no hurry for these and the page will transition from
PENDING to NEEDWRITE and will then be written, though if it ever
becomes DIRTY it will be written much sooner and PENDING will be
cleared.
Secondly, a page of counters - which contains PAGE_SIZE/2 counters, one
for each bit, can usefully have a 'pending' flag which indicates if
any of the counters are low (2 or 1) and ready to be processed by
bitmap_daemon_work(). If this flag is clear we can skip the whole
page.
These two concepts are currently combined in the bitmap-file flag.
This causes a tighter connection between the counters and the bitmap
file than I would like - as I want to add some flexibility to the
bitmap file.
So introduce a new flag with the page-of-counters, and rewrite
bitmap_daemon_work() so that it handles the two different 'pending'
concepts separately.
This also allows us to clear BITMAP_PAGE_PENDING when we write out
a dirty page, which may occasionally reduce the number of times we
write a page.
Signed-off-by: NeilBrown <neilb@suse.de>
commit 61a0d80c "md/bitmap: discard CHUNK_BLOCK_SHIFT macro"
replaced CHUNK_BLOCK_RATIO() by the same text that was
replacing CHUNK_BLOCK_SHIFT() - which is clearly wrong.
The result is that 'chunks' is often too small by 1,
which can sometimes result in a crash (not sure how).
So use the correct replacement, and get rid of CHUNK_BLOCK_RATIO
which is no longe used.
Reported-by: Karl Newman <siliconfiend@gmail.com>
Tested-by: Karl Newman <siliconfiend@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
If a bitmap is added while the array is active, it is possible
for bitmap_daemon_work to run while the bitmap is being
initialised.
This is particularly a problem if bitmap_daemon_work sees
bitmap->filemap as non-NULL before it has been filled in properly.
So hold bitmap_info.mutex while filling in ->filemap
to prevent problems.
This patch is suitable for any -stable kernel, though it might not
apply cleanly before about 3.1.
Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
bitmap_new_disk_sb() would still create V3 bitmap superblock
with host-endian layout.
Perhaps I'm confused, but shouldn't bitmap_new_disk_sb() be
creating a V4 bitmap superblock instead, that is portable,
as per comment in bitmap.h?
Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Pull md updates for 3.4 from Neil Brown:
"Mostly tidying up code in preparation for some bigger changes next
time.
A few bug fixes tagged for -stable.
Main functionality change is that some RAID10 arrays can now grow to
use extra space that may have been made available on the individual
devices."
Fixed up trivial conflicts with the k[un]map_atomic() cleanups in
drivers/md/bitmap.c.
* tag 'md-3.4' of git://neil.brown.name/md: (22 commits)
md: Add judgement bb->unacked_exist in function md_ack_all_badblocks().
md: fix clearing of the 'changed' flags for the bad blocks list.
md/bitmap: discard CHUNK_BLOCK_SHIFT macro
md/bitmap: remove unnecessary indirection when allocating.
md/bitmap: remove some pointless locking.
md/bitmap: change a 'goto' to a normal 'if' construct.
md/bitmap: move printing of bitmap status to bitmap.c
md/bitmap: remove some unused noise from bitmap.h
md/raid10 - support resizing some RAID10 arrays.
md/raid1: handle merge_bvec_fn in member devices.
md/raid10: handle merge_bvec_fn in member devices.
md: add proper merge_bvec handling to RAID0 and Linear.
md: tidy up rdev_for_each usage.
md/raid1,raid10: avoid deadlock during resync/recovery.
md/bitmap: ensure to load bitmap when creating via sysfs.
md: don't set md arrays to readonly on shutdown.
md: allow re-add to failed arrays.
md/raid5: use atomic_dec_return() instead of atomic_dec() and atomic_read().
md: Use existed macros instead of numbers
md/raid5: removed unused 'added_devices' variable.
...
Be redefining ->chunkshift as the shift from sectors to chunks rather
than bytes to chunks, we can just use "bitmap->chunkshift" which is
shorter than the macro call, and less indirect.
Signed-off-by: NeilBrown <neilb@suse.de>
These funcitons don't add anything useful except possibly the trace
points, and I don't think they are worth the extra indirection.
So remove them.
Signed-off-by: NeilBrown <neilb@suse.de>
There is nothing gained by holding a lock while we check if a pointer
is NULL or not. If there could be a race, then it could become NULL
immediately after the unlock - but there is no race here.
So just remove the locking.
Signed-off-by: NeilBrown <neilb@suse.de>
The use of a goto makes the control flow more obscure here.
So make it a normal:
if (x) {
Y;
}
No functional change.
Signed-off-by: NeilBrown <neilb@suse.de>
The part of /proc/mdstat which describes the bitmap should really
be generated by code in bitmap.c. So move it there.
Signed-off-by: NeilBrown <neilb@suse.de>
md.h has an 'rdev_for_each()' macro for iterating the rdevs in an
mddev. However it uses the 'safe' version of list_for_each_entry,
and so requires the extra variable, but doesn't include 'safe' in the
name, which is useful documentation.
Consequently some places use this safe version without needing it, and
many use an explicity list_for_each entry.
So:
- rename rdev_for_each to rdev_for_each_safe
- create a new rdev_for_each which uses the plain
list_for_each_entry,
- use the 'safe' version only where needed, and convert all other
list_for_each_entry calls to use rdev_for_each.
Signed-off-by: NeilBrown <neilb@suse.de>
When commit 69e51b449d (md/bitmap: separate out loading a bitmap...)
created bitmap_load, it missed calling it after bitmap_create when a
bitmap is created through the sysfs interface.
So if a bitmap is added this way, we don't allocate memory properly
and can crash.
This is suitable for any -stable release since 2.6.35.
Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
For each active region corresponding to a bit in the bitmap with have
a 14bit counter (and some flags).
This counts
number of active writes + bit in the on-disk bitmap + delay-needed.
The "delay-needed" is because we always want a delay before clearing a
bit. So the number here is normally number of active writes plus 2.
If there have been no writes for a while, we drop to 1.
If still no writes we clear the bit and drop to 0.
So for consistency, when setting bit from the on-disk bitmap or by
request from user-space it is best to set the counter to '2' to start
with.
In particular we might also set the NEEDED_MASK flag at this time, and
in all other cases NEEDED_MASK is only set when the counter is 2 or
more.
Signed-off-by: NeilBrown <neilb@suse.de>
We have a variable 'mddev' in this function, but repeatedly get the
same value by dereferencing bitmap->mddev.
There is room for simplification here...
Signed-off-by: NeilBrown <neilb@suse.de>
commit d0a4bb4927 introduced a
regression which is annoying but fairly harmless.
When writing to an array that is undergoing recovery (a spare
in being integrated into the array), writing to the array will
set bits in the bitmap, but they will not be cleared when the
write completes.
For bits covering areas that have not been recovered yet this is not a
problem as the recovery will clear the bits. However bits set in
already-recovered region will stay set and never be cleared.
This doesn't risk data integrity. The only negatives are:
- next time there is a crash, more resyncing than necessary will
be done.
- the bitmap doesn't look clean, which is confusing.
While an array is recovering we don't want to update the
'events_cleared' setting in the bitmap but we do still want to clear
bits that have very recently been set - providing they were written to
the recovering device.
So split those two needs - which previously both depended on 'success'
and always clear the bit of the write went to all devices.
Signed-off-by: NeilBrown <neilb@suse.de>
NeilBrown
Andrei Warkentin
Linus Torvalds
Cong Wang