linux-toradex.git/drivers/md/bitmap.c, branch v3.2.46

md/bitmap: prevent bitmap_daemon_work running while initialising bitmap

2012-04-22T22:30:58+00:00

commit afbaa90b80b1ec66e5137cc3824746bfdf559b18 upstream.

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.

Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

md/bitmap: ensure to load bitmap when creating via sysfs.

2012-04-02T16:52:46+00:00

commit 4474ca42e2577563a919fd3ed782e2ec55bf11a2 upstream.

When commit 69e51b449d383e (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.
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

md/bitmap: It is OK to clear bits during recovery.

2011-12-22T22:57:48+00:00

commit d0a4bb492772ce5c4bdfba3744a99ed6f6fb238f 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

md/lock: ensure updates to page_attrs are properly locked.

2011-11-22T23:18:52+00:00

Page attributes are set using __set_bit rather than set_bit as
it normally called under a spinlock so the extra atomicity is not
needed.

However there are two places where we might set or clear page
attributes without holding the spinlock.
So add the spinlock in those cases.

This might be the cause of occasional reports that bits a aren't
getting clear properly - theory is that BITMAP_PAGE_PENDING gets lost
when BITMAP_PAGE_NEEDWRITE is set or cleared.  This is an
inconvenience, not a threat to data safety.

Signed-off-by: NeilBrown

md/bitmap remove fault injection options.

2011-10-11T05:49:56+00:00

These are too hard to use to be much more than noise.

Signed-off-by: NeilBrown

md: remove typedefs: mddev_t -> struct mddev

2011-10-11T05:47:53+00:00

Having mddev_t and 'struct mddev_s' is ugly and not preferred

Signed-off-by: NeilBrown

md: removing typedefs: mdk_rdev_t -> struct md_rdev

2011-10-11T05:45:26+00:00

The typedefs are just annoying. 'mdk' probably refers to 'md_k.h'
which used to be an include file that defined this thing.

Signed-off-by: NeilBrown

md: remove PRINTK and dprintk debugging and use pr_debug

2011-10-07T03:23:17+00:00

Being able to dynamically enable these make them much more useful.

Signed-off-by: NeilBrown

md/bitmap: improve handling of 'allclean'.

2011-09-21T05:37:46+00:00

The 'allclean' flag is used to cache the fact that there is nothing to
do, so we can avoid waking up and scanning the bitmap regularly.

The two sorts of pages that might need the attention of the bitmap
daemon are BITMAP_PAGE_PENDING and BITMAP_PAGE_NEEDWRITE pages.

So make sure allclean reflects exactly when there are none of those.
So:
  set it before scanning all pages with either bit set.
  clear it whenever these bits are set
  clear it when we desire not to clear one of these bits.
  don't clear it any other time.

Signed-off-by: NeilBrown

md/bitmap: rename and tidy up BITMAP_PAGE_CLEAN

2011-09-21T05:37:46+00:00

The flag 'BITMAP_PAGE_CLEAN' has a confusing name as it doesn't mean
that the page is clean, but rather that there are counters in the page
which allow bits in the bitmap to be cleared - i.e. maybe cleaning can
happen.

So change it to BITMAP_PAGE_PENDING and fix some irregularities:
 - Don't set it in bitmap_init_from_disk as bitmap_set_memory_bits
   sets it when needed
 - in bitmap_daemon_work, if we find a counter that is '1', but
   need_sync is set, then set BITMAP_PAGE_PENDING again (it was
   recently cleared) to ensure we don't forget about this bit.

Signed-off-by: NeilBrown