linux-toradex.git/drivers/md/raid5.c, branch v3.7

md/raid5: Make sure we clear R5_Discard when discard is finished.

2012-11-21T22:14:13+00:00

commit 9e44476851e91c86c98eb92b9bc27fb801f89072
    MD: raid5 avoid unnecessary zero page for trim

change raid5 to clear R5_Discard when the complete request is
handled rather than when submitting the per-device discard request.
However it did not clear R5_Discard for the parity device.

This means that if the stripe_head was reused before it expired from
the cache, the setting would be wrong and a hang would result.

Also if the R5_Uptodate bit happens to be set, R5_Discard again
won't be cleared.  But R5_Uptodate really should be clear at this point.

So make sure R5_Discard is cleared in all cases, and clear
R5_Uptodate when a 'discard' completes.

Signed-off-by: NeilBrown

md/raid5: move resolving of reconstruct_state earlier in

2012-11-21T22:14:09+00:00

stripe_handle.

The chunk of code in stripe_handle which responds to a
*_result value in reconstruct_state is really the completion
of some processing that happened outside of handle_stripe
(possibly asynchronously) and so should be one of the first
things done in handle_stripe().

After the next patch it will be important that it happens before
handle_stripe_clean_event(), as that will clear some dev->flags
bit that this code tests.

Signed-off-by: NeilBrown

md/raid5: round discard alignment up to power of 2.

2012-11-20T08:42:56+00:00

blkdev_issue_discard currently assumes that the granularity
is a power of 2.  So in raid5, round the chosen number up to
avoid embarrassment.

Cc: Shaohua Li 
Signed-off-by: NeilBrown

Merge tag 'md-3.7' of git://neil.brown.name/md

2012-10-13T20:22:01+00:00

Pull md updates from NeilBrown:
 - "discard" support, some dm-raid improvements and other assorted bits
   and pieces.

* tag 'md-3.7' of git://neil.brown.name/md: (29 commits)
  md: refine reporting of resync/reshape delays.
  md/raid5: be careful not to resize_stripes too big.
  md: make sure manual changes to recovery checkpoint are saved.
  md/raid10: use correct limit variable
  md: writing to sync_action should clear the read-auto state.
  Subject: [PATCH] md:change resync_mismatches to atomic64_t to avoid races
  md/raid5: make sure to_read and to_write never go negative.
  md: When RAID5 is dirty, force reconstruct-write instead of read-modify-write.
  md/raid5: protect debug message against NULL derefernce.
  md/raid5: add some missing locking in handle_failed_stripe.
  MD: raid5 avoid unnecessary zero page for trim
  MD: raid5 trim support
  md/bitmap:Don't use IS_ERR to judge alloc_page().
  md/raid1: Don't release reference to device while handling read error.
  raid: replace list_for_each_continue_rcu with new interface
  add further __init annotations to crypto/xor.c
  DM RAID: Fix for "sync" directive ineffectiveness
  DM RAID: Fix comparison of index and quantity for "rebuild" parameter
  DM RAID: Add rebuild capability for RAID10
  DM RAID: Move 'rebuild' checking code to its own function
  ...

md/raid5: be careful not to resize_stripes too big.

2012-10-11T03:24:13+00:00

When a RAID5 is reshaping, conf->raid_disks is increased
before mddev->delta_disks becomes zero.
This can result in check_reshape calling resize_stripes with a
number that is too large.  This particularly happens
when md_check_recovery calls ->check_reshape().

If we use ->previous_raid_disks, we don't risk this.

Signed-off-by: NeilBrown

Subject: [PATCH] md:change resync_mismatches to atomic64_t to avoid races

2012-10-11T03:17:59+00:00

Now that multiple threads can handle stripes, it is safer to
use an atomic64_t for resync_mismatches, to avoid update races.

Signed-off-by: Jianpeng Ma 
Signed-off-by: NeilBrown

md/raid5: make sure to_read and to_write never go negative.

2012-10-11T02:50:13+00:00

to_read and to_write are part of the result of analysing
a stripe before handling it.
Their use is to avoid some loops and tests if the values are
known to be zero.  Thus it is not a problem if they are a
little bit larger than they should be.

So decrementing them in handle_failed_stripe serves little value, and
due to races it could cause some loops to be skipped incorrectly.

So remove those decrements.

Reported-by: "Jianpeng Ma" 
Signed-off-by: NeilBrown

md: When RAID5 is dirty, force reconstruct-write instead of read-modify-write.

2012-10-11T02:50:12+00:00

Signed-off-by: Alex Lyakas 
Suggested-by: Yair Hershko 
Signed-off-by: NeilBrown

md/raid5: protect debug message against NULL derefernce.

2012-10-11T02:50:12+00:00

The pr_debug in add_stripe_bio could race with something
changing *bip, so it is best to hold the lock until
after the pr_debug.

Reported-by: "Jianpeng Ma" 
Signed-off-by: NeilBrown

md/raid5: add some missing locking in handle_failed_stripe.

2012-10-11T02:50:12+00:00

We really should hold the stripe_lock while accessing
'toread' else we could race with add_stripe_bio and corrupt
a list.

Reported-by: "Jianpeng Ma" 
Signed-off-by: NeilBrown