linux.git/drivers/md/raid10.c, branch v2.6.22-rc4

[PATCH] md: fix raid10 recovery problem.

2007-03-01T22:53:36+00:00

There are two errors that can lead to recovery problems with raid10
when used in 'far' more (not the default).

Due to a '>' instead of '>=' the wrong block is located which would result in
garbage being written to some random location, quite possible outside the
range of the device, causing the newly reconstructed device to fail.

The device size calculation had some rounding errors (it didn't round when it
should) and so recovery would go a few blocks too far which would again cause
a write to a random block address and probably a device error.

The code for working with device sizes was fairly confused and spread out, so
this has been tided up a bit.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: pass down BIO_RW_SYNC in raid{1,10}

2007-01-12T02:18:21+00:00

md raidX make_request functions strip off the BIO_RW_SYNC flag, thus
introducing additional latency.

Fixing this in raid1 and raid10 seems to be straightforward enough.

For our particular usage case in DRBD, passing this flag improved some
initialization time from ~5 minutes to ~5 seconds.

Acked-by: NeilBrown 
Signed-off-by: Lars Ellenberg 
Acked-by: Jens Axboe 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: Don't assume that READ==0 and WRITE==1 - use the names explicitly

2006-12-13T17:05:48+00:00

Thanks Jens for alerting me to this.

Cc: Jens Axboe 
Cc: 
Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: fix printk format warnings, seen on powerpc64:

2006-10-28T18:30:52+00:00

drivers/md/raid1.c:1479: warning: long long unsigned int format, long unsigned int arg (arg 4)
drivers/md/raid10.c:1475: warning: long long unsigned int format, long unsigned int arg (arg 4)

Signed-off-by: Randy Dunlap 
Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: fix calculation of ->degraded for multipath and raid10

2006-10-21T20:35:05+00:00

Two less-used md personalities have bugs in the calculation of ->degraded (the
extent to which the array is degraded).

Signed-off-by: Neil Brown 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: define ->congested_fn for raid1, raid10, and multipath

2006-10-03T15:04:18+00:00

raid1, raid10 and multipath don't report their 'congested' status through
bdi_*_congested, but should.

This patch adds the appropriate functions which just check the 'congested'
status of all active members (with appropriate locking).

raid1 read_balance should be modified to prefer devices where
bdi_read_congested returns false.  Then we could use the '&' branch rather
than the '|' branch.  However that should would need some benchmarking first
to make sure it is actually a good idea.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: Improve locking around error handling

2006-10-03T15:04:18+00:00

The error handling routines don't use proper locking, and so two concurrent
errors could trigger a problem.

So:
  - use test-and-set and test-and-clear to synchonise
    the In_sync bits with the ->degraded count
  - use the spinlock to protect updates to the
    degraded count (could use an atomic_t but that
    would be a bigger change in code, and isn't
    really justified)
  - remove un-necessary locking in raid5

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: remove 'working_disks' from raid10 state

2006-10-03T15:04:17+00:00

It isn't needed as mddev->degraded contains equivalent info.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: replace magic numbers in sb_dirty with well defined bit flags

2006-10-03T15:04:17+00:00

Instead of magic numbers (0,1,2,3) in sb_dirty, we have
some flags instead:
MD_CHANGE_DEVS
   Some device state has changed requiring superblock update
   on all devices.
MD_CHANGE_CLEAN
   The array has transitions from 'clean' to 'dirty' or back,
   requiring a superblock update on active devices, but possibly
   not on spares
MD_CHANGE_PENDING
   A superblock update is underway.

We wait for an update to complete by waiting for all flags to be clear.  A
flag can be set at any time, even during an update, without risk that the
change will be lost.

Stop exporting md_update_sb - isn't needed.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] md: factor out part of raid10d into a separate function.

2006-10-03T15:04:17+00:00

raid10d has toooo many nested block, so take the fix_read_error functionality
out into a separate function.

Signed-off-by: Neil Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds