linux.git/drivers/md/raid1.c, branch v2.6.21.7

md: Fix bug in error handling during raid1 repair.

2007-08-04T16:10:23+00:00

If raid1/repair (which reads all block and fixes any differences
it finds) hits a read error, it doesn't reset the bio for writing
before writing correct data back, so the read error isn't fixed,
and the device probably gets a zero-length write which it might
complain about.

Signed-off-by: Neil Brown 
Signed-off-by: Chris Wright 
Signed-off-by: Greg Kroah-Hartman

[PATCH] md: Avoid a possibility that a read error can wrongly propagate through md/raid1 to a filesystem.

2007-05-23T21:32:48+00:00

When a raid1 has only one working drive, we want read error to
propagate up to the filesystem as there is no point failing the last
drive in an array.

Currently the code perform this check is racy.  If a write and a read
a both submitted to a device on a 2-drive raid1, and the write fails
followed by the read failing, the read will see that there is only one
working drive and will pass the failure up, even though the one
working drive is actually the *other* one.

So, tighten up the locking.

Signed-off-by: Neil Brown 
Signed-off-by: Chris Wright

[PATCH] md: fix potential memalloc deadlock in md

2007-01-26T21:51:00+00:00

If a GFP_KERNEL allocation is attempted in md while the mddev_lock is held,
it is possible for a deadlock to eventuate.

This happens if the array was marked 'clean', and the memalloc triggers a
write-out to the md device.

For the writeout to succeed, the array must be marked 'dirty', and that
requires getting the mddev_lock.

So, before attempting a GFP_KERNEL allocation while holding the lock, make
sure the array is marked 'dirty' (unless it is currently read-only).

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

[PATCH] md: make 'repair' actually work for raid1

2007-01-26T21:50:59+00:00

When 'repair' finds a block that is different one the various parts of the
mirror.  it is meant to write a chosen good version to the others.  However it
currently writes out the original data to each.  The memcpy to make all the
data the same is missing.

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: assorted md and raid1 one-liners

2006-12-10T17:57:21+00:00

Fix few bugs that meant that:
  - superblocks weren't alway written at exactly the right time (this
    could show up if the array was not written to - writting to the array
    causes lots of superblock updates and so hides these errors).

  - restarting device recovery after a clean shutdown (version-1 metadata
    only) didn't work as intended (or at all).

1/ Ensure superblock is updated when a new device is added.
2/ Remove an inappropriate test on MD_RECOVERY_SYNC in md_do_sync.
   The body of this if takes one of two branches depending on whether
   MD_RECOVERY_SYNC is set, so testing it in the clause of the if
   is wrong.
3/ Flag superblock for updating after a resync/recovery finishes.
4/ If we find the neeed to restart a recovery in the middle (version-1
   metadata only) make sure a full recovery (not just as guided by
   bitmaps) does get done.

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: 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