linux-toradex.git/include/linux/raid, branch v2.6.17.12

[PATCH] md: make sure 64bit fields in version-1 metadata are 64-bit aligned

2006-04-11T13:18:30+00:00

reshape_position is a 64bit field that was not 64bit aligned.  So swap with
new_level.

NOTE: this is a user-visible change.  However:
  - The bad code has not appeared in a released kernel
  - This code is still marked 'experimental'
  - This only affects version-1 superblock, which are not in wide use
  - These field are only used (rather than simply reported) by user-space
    tools in extemely rare circumstances : after a reshape crashes in the
    first second of the reshape process.

So I believe that, at this stage, the change is safe.  Especially if people
heed the 'help' message on use mdadm-2.4.1.

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

[PATCH] md: Convert reconfig_sem to reconfig_mutex

2006-03-27T16:45:03+00:00

... being careful that mutex_trylock is inverted wrt down_trylock

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

[PATCH] md: Support suspending of IO to regions of an md array

2006-03-27T16:45:02+00:00

This allows user-space to access data safely.  This is needed for raid5
reshape as user-space needs to take a backup of the first few stripes before
allowing reshape to commence.

It will also be useful in cluster-aware raid1 configurations so that all
cluster members can leave a section of the array untouched while a
resync/recovery happens.

A 'start' and 'end' of the suspended range are written to 2 sysfs attributes.
Note that only one range can be suspended at a time.

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

[PATCH] md: Split reshape handler in check_reshape and start_reshape

2006-03-27T16:45:02+00:00

check_reshape checks validity and does things that can be done instantly -
like adding devices to raid1.  start_reshape initiates a restriping process to
convert the whole array.

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

[PATCH] md: Only checkpoint expansion progress occasionally

2006-03-27T16:45:02+00:00

Instead of checkpointing at each stripe, only checkpoint when a new write
would overwrite uncheckpointed data.  Block any write to the uncheckpointed
area.  Arbitrarily checkpoint at least every 3Meg.

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

[PATCH] md: Checkpoint and allow restart of raid5 reshape

2006-03-27T16:45:01+00:00

We allow the superblock to record an 'old' and a 'new' geometry, and a
position where any conversion is up to.  The geometry allows for changing
chunksize, layout and level as well as number of devices.

When using verion-0.90 superblock, we convert the version to 0.91 while the
conversion is happening so that an old kernel will refuse the assemble the
array.  For version-1, we use a feature bit for the same effect.

When starting an array we check for an incomplete reshape and restart the
reshape process if needed.  If the reshape stopped at an awkward time (like
when updating the first stripe) we refuse to assemble the array, and let
user-space worry about it.

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

[PATCH] md: Final stages of raid5 expand code

2006-03-27T16:45:01+00:00

This patch adds raid5_reshape and end_reshape which will start and finish the
reshape processes.

raid5_reshape is only enabled in CONFIG_MD_RAID5_RESHAPE is set, to discourage
accidental use.

Read the 'help' for the CONFIG_MD_RAID5_RESHAPE entry.

and Make sure that you have backups, just in case.

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

[PATCH] md: Core of raid5 resize process

2006-03-27T16:45:01+00:00

This patch provides the core of the resize/expand process.

sync_request notices if a 'reshape' is happening and acts accordingly.

It allocated new stripe_heads for the next chunk-wide-stripe in the target
geometry, marking them STRIPE_EXPANDING.

Then it finds which stripe heads in the old geometry can provide data needed
by these and marks them STRIPE_EXPAND_SOURCE.  This causes stripe_handle to
read all blocks on those stripes.

Once all blocks on a STRIPE_EXPAND_SOURCE stripe_head are read, any that are
needed are copied into the corresponding STRIPE_EXPANDING stripe_head.  Once a
STRIPE_EXPANDING stripe_head is full, it is marks STRIPE_EXPAND_READY and then
is written out and released.

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

[PATCH] md: Infrastructure to allow normal IO to continue while array is expanding

2006-03-27T16:45:01+00:00

We need to allow that different stripes are of different effective sizes, and
use the appropriate size.  Also, when a stripe is being expanded, we must
block any IO attempts until the stripe is stable again.

Key elements in this change are:
 - each stripe_head gets a 'disk' field which is part of the key,
   thus there can sometimes be two stripe heads of the same area of
   the array, but covering different numbers of devices.  One of these
   will be marked STRIPE_EXPANDING and so won't accept new requests.
 - conf->expand_progress tracks how the expansion is progressing and
   is used to determine whether the target part of the array has been
   expanded yet or not.

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

[PATCH] md: Allow stripes to be expanded in preparation for expanding an array

2006-03-27T16:45:01+00:00

Before a RAID-5 can be expanded, we need to be able to expand the stripe-cache
data structure.

This requires allocating new stripes in a new kmem_cache.  If this succeeds,
we copy cache pages over and release the old stripes and kmem_cache.

We then allocate new pages.  If that fails, we leave the stripe cache at it's
new size.  It isn't worth the effort to shrink it back again.

Unfortuanately this means we need two kmem_cache names as we, for a short
period of time, we have two kmem_caches.  So they are raid5/%s and
raid5/%s-alt

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