If a Replacement is seen, file it as such.
If we see two replacements (or two normal devices) for the one slot,
abort.
Signed-off-by: NeilBrown <neilb@suse.de>
When recovery completes ->spare_active is called.
This checks if the replacement is ready and if so it fails
the original.
Signed-off-by: NeilBrown <neilb@suse.de>
In RAID1, a replacement is much like a normal device, so we just
double the size of the relevant arrays and look at all possible
devices for reads and writes.
This means that the array looks like it is now double the size in some
way - we need to be careful about that.
In particular, we checking if the array is still degraded while
creating a recovery request we need to only consider the first 'half'
- i.e. the real (non-replacement) devices.
Signed-off-by: NeilBrown <neilb@suse.de>
In general mddev->raid_disks can change unexpectedly while
conf->raid_disks will only change in a very controlled way. So change
some uses of one to the other.
The use of mddev->raid_disks will not cause actually problems but
this way is more consistent and safer in the long term.
Signed-off-by: NeilBrown <neilb@suse.de>
When attempting to add a spare to a RAID10 array, also consider
adding it as a replacement for a want_replacement device.
Signed-off-by: NeilBrown <neilb@suse.de>
If a Replacement is seen, file it as such.
If we see two replacements (or two normal devices) for the one slot,
abort.
Signed-off-by: NeilBrown <neilb@suse.de>
When recovery finish and spare_active is called, check for a
replace that might have just become fully synced and mark it
as such, marking the original as failed.
Then when the original is removed, move the replacement into
its position.
This means that 'replacement' and spontaneously become NULL in some
situations. Make sure we check for those.
It also means that 'rdev' and 'replacement' could appear to be
identical - check for that too.
Signed-off-by: NeilBrown <neilb@suse.de>
If there is a replacement device, then recover to it,
reading from any drives - maybe the one being replaced, maybe not.
Signed-off-by: NeilBrown <neilb@suse.de>
If we need to resync an array which has replacement devices,
we always write any block checked to every replacement.
If the resync was bitmap-based resync we will then complete the
replacement normally.
If it was a full resync, we mark the replacements as fully recovered
when the resync finishes so no further recovery is needed.
Signed-off-by: NeilBrown <neilb@suse.de>
When writing, we need to submit two writes, one to the original,
and one to the replacements - if there is a replacement.
If the write to the replacement results in a write error we just
fail the device. We only try to record write errors to the
original.
This only handles writing new data. Writing for resync/recovery
will come later.
Signed-off-by: NeilBrown <neilb@suse.de>
When reading (for array reads, not for recovery etc) we read from the
replacement device if it has recovered far enough.
This requires storing the chosen rdev in the 'r10_bio' so we can make
sure to drop the ref on the right device when the read finishes.
Signed-off-by: NeilBrown <neilb@suse.de>
It makes more sense to return an rdev than just an index as
read_balance() gets a reference to the rdev and so returning
the pointer make this more idiomatic.
This will be needed in a future patch when we might return
a 'replacement' rdev instead of the main rdev.
Signed-off-by: NeilBrown <neilb@suse.de>
Allow each slot in the RAID10 to have 2 devices, the want_replacement
and the replacement.
Also an r10bio to have 2 bios, and for resync/recovery allocate the
second bio if there are any replacement devices.
Signed-off-by: NeilBrown <neilb@suse.de>
Now that WantReplacement drives are replaced cleanly, mark a drive
as WantReplacement when we see a write error. It might get failed soon so
the WantReplacement flag is irrelevant, but if the write error is recorded
in the bad block log, we still want to activate any spare that might
be available.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
When attempting to add a spare to a RAID[456] array, also consider
adding it as a replacement for a want_replacement device.
This requires that common md code attempt hot_add even when the array
is not formally degraded.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
If a Replacement is seen, file it as such.
If we see two replacements (or two normal devices) for the one slot,
abort.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
When recovery completes - as reported by a call to ->spare_active,
we clear In_sync on the original and set it on the replacement.
Then when the original gets removed we move the replacement from
'replacement' to 'rdev'.
This could race with other code that is looking at these pointers,
so we use memory barriers and careful ordering to ensure that
a reader might see one device twice, but never no devices.
Then the readers guard against using both devices, which could
only happen when writing.
Signed-off-by: NeilBrown <neilb@suse.de>
During recovery we want to write to the replacement but not
the original. So we have two new flags
- R5_NeedReplace if this stripe has a replacement that needs to
be written at some stage
- R5_WantReplace if NeedReplace, and the data is available, and
a 'sync' has been requested on this stripe.
We also distinguish between 'sync and replace' which need to read
all other devices, and 'replace' which only needs to read the
devices being replaced.
Note that during resync we always write to any replacement device.
It might not need to be written to, but as we don't read to compare,
we have to write to be sure.
Signed-off-by: NeilBrown <neilb@suse.de>
When writing, we need to submit two writes, one to the original, and
one to the replacement - if there is a replacement.
If the write to the replacement results in a write error, we just fail
the device. We only try to record write errors to the original.
When writing for recovery, we shouldn't write to the original. This
will be addressed in a subsequent patch that generally addresses
recovery.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Enhance raid5_remove_disk to be able to remove ->replacement
as well as ->rdev.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
If a replacement device is present and has been recovered far enough,
then use it for reading into the stripe cache.
If we get an error we don't try to repair it, we just fail the device.
A replacement device that gives errors does not sound sensible.
This requires removing the setting of R5_ReadError when we get
a read error during a read that bypasses the cache. It was probably
a bad idea anyway as we don't know that every block in the read
caused an error, and it could cause ReadError to be set for the
replacement device, which is bad.
Signed-off-by: NeilBrown <neilb@suse.de>
We current initialise some fields of a bio when preparing a
stripe_head, and again just before submitting the request.
Remove the duplication by only setting the fields that lower level
devices don't touch in raid5_build_block, and only set the changeable
fields in ops_run_io.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Remove some #defines that are no longer used, and replace some
others with an enum.
And remove an unused field.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
NeilBrown