copy_complete()'s processing of out_of_order_list can result in
quadratic complexity in the worst case. As such it was the source of
consuming too much cpu and the source of significant loss in
performance.
Fix this by converting out_of_order_list to an rbtree. This improved
a dm-snapshot test copy workload from 32 seconds to 4 seconds.
Signed-off-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Brett Hull <bhull@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
policy_hint_size starts as 0 during __write_initial_superblock(). It
isn't until the policy is loaded that policy_hint_size is set in-core
(cmd->policy_hint_size). But it never got recorded in the on-disk
superblock because __commit_transaction() didn't deal with transfering
the in-core cmd->policy_hint_size to the on-disk superblock.
The in-core cmd->policy_hint_size gets initialized by metadata_open()'s
__begin_transaction_flags() which re-reads all superblock fields.
Because the superblock's policy_hint_size was never properly stored, when
the cache was created, hints_array_available() would always return false
when re-activating a previously created cache. This means
__load_mappings() always considered the hints invalid and never made use
of the hints (these hints served to optimize).
Another detremental side-effect of this oversight is the cache_check
utility would fail with: "invalid hint width: 0"
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Now both check_for_space() and do_no_space_timeout() will read & write
pool->pf.error_if_no_space. If these functions run concurrently, as
shown in the following case, the default setting of "queue_if_no_space"
can get lost.
precondition:
* error_if_no_space = false (aka "queue_if_no_space")
* pool is in Out-of-Data-Space (OODS) mode
* no_space_timeout worker has been queued
CPU 0: CPU 1:
// delete a thin device
process_delete_mesg()
// check_for_space() invoked by commit()
set_pool_mode(pool, PM_WRITE)
pool->pf.error_if_no_space = \
pt->requested_pf.error_if_no_space
// timeout, pool is still in OODS mode
do_no_space_timeout
// "queue_if_no_space" config is lost
pool->pf.error_if_no_space = true
pool->pf.mode = new_mode
Fix it by stopping no_space_timeout worker when switching to write mode.
Fixes: bcc696fac1 ("dm thin: stay in out-of-data-space mode once no_space_timeout expires")
Cc: stable@vger.kernel.org
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
During raid5 replacement, the stripes can be marked with R5_NeedReplace
flag. Data can be read from being-replaced devices and written to
replacing spares without reading all other devices. (It's 'replace'
mode. s.replacing = 1) If a being-replaced device is dropped, the
replacement progress will be interrupted and resumed with pure recovery
mode. However, existing stripes before being interrupted cannot read
from the dropped device anymore. It prints lots of WARN_ON messages.
And it results in data corruption because existing stripes write
problematic data into its replacement device and update the progress.
\# Erase disks (1MB + 2GB)
dd if=/dev/zero of=/dev/sda bs=1MB count=2049
dd if=/dev/zero of=/dev/sdb bs=1MB count=2049
dd if=/dev/zero of=/dev/sdc bs=1MB count=2049
dd if=/dev/zero of=/dev/sdd bs=1MB count=2049
mdadm -C /dev/md0 -amd -R -l5 -n3 -x0 /dev/sd[abc] -z 2097152
\# Ensure array stores non-zero data
dd if=/root/data_4GB.iso of=/dev/md0 bs=1MB
\# Start replacement
mdadm /dev/md0 -a /dev/sdd
mdadm /dev/md0 --replace /dev/sda
Then, Hot-plug out /dev/sda during recovery, and wait for recovery done.
echo check > /sys/block/md0/md/sync_action
cat /sys/block/md0/md/mismatch_cnt # it will be greater than 0.
Soon after you hot-plug out /dev/sda, you will see many WARN_ON
messages. The replacement recovery will be interrupted shortly. After
the recovery finishes, it will result in data corruption.
Actually, it's just an unhandled case of replacement. In commit
<f94c0b6658c7> (md/raid5: fix interaction of 'replace' and 'recovery'.),
if a NeedReplace device is not UPTODATE then that is an error, the
commit just simply print WARN_ON but also mark these corrupted stripes
with R5_WantReplace. (it means it's ready for writes.)
To fix this case, we can leverage 'sync and replace' mode mentioned in
commit <9a3e1101b827> (md/raid5: detect and handle replacements during
recovery.). We can add logics to detect and use 'sync and replace' mode
for these stripes.
Reported-by: Alex Chen <alexchen@synology.com>
Reviewed-by: Alex Wu <alexwu@synology.com>
Reviewed-by: Chung-Chiang Cheng <cccheng@synology.com>
Signed-off-by: BingJing Chang <bingjingc@synology.com>
Signed-off-by: Shaohua Li <shli@fb.com>
bitmap API (include/linux/bitmap.h) has 'bitmap' prefix for its methods.
On the other hand MD bitmap API is special case.
Adding 'md' prefix to it to avoid name space collision.
No functional changes intended.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Shaohua Li <shli@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
bitmap API (include/linux/bitmap.h) has 'bitmap' prefix for its methods.
On the other hand DM bitmap API is special case.
Adding 'dm' prefix to it to avoid potential name space collision.
No functional changes intended.
Suggested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
dm_kcopyd_copy() only ever returns 0 so there is no need for callers to
account for possible failure. Same goes for dm_kcopyd_zero().
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Function persistent_memory_claim doesn't need to get local pointer
dummy_addr from direct_access. Using NULL instead of having to pass
in a useless local pointer that caller then just throw away.
Suggested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
The metadata low watermark threshold is set by the kernel. But the
kernel depends on userspace to extend the thinpool metadata device when
the threshold is crossed.
Since the metadata low watermark threshold is not visible to userspace,
upon receiving an event, userspace cannot tell that the kernel wants the
metadata device extended, instead of some other eventing condition.
Making it visible (but not settable) enables userspace to affirmatively
know the kernel is asking for a metadata device extension, by comparing
metadata_low_watermark against nr_free_blocks_metadata, also reported in
status.
Current solutions like dmeventd have their own thresholds for extending
the data and metadata devices, and both devices are checked against
their thresholds on each event. This lessens the value of the kernel-set
threshold, since userspace will either extend the metadata device sooner,
when receiving another event; or will receive the metadata lowater event
and do nothing, if dmeventd's threshold is less than the kernel's.
(This second case is dangerous. The metadata lowater event will not be
re-sent, so no further event will be generated before the metadata
device is out if space, unless some other event causes userspace to
recheck its thresholds.)
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This is a small simplification of dm-crypt - use wake_up_process()
instead of a wait queue in a case where only one process may be
waiting. dm-writecache uses a similar pattern.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
When using external metadata device and internal hash, recalculate the
checksums when the device is created - so that dm-integrity doesn't
have to overwrite the device. The superblock stores the last position
when the recalculation ended, so that it is properly restarted.
Integrity tags that haven't been recalculated yet are ignored.
Also bump the target version.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Flush the journal on suspend when using separate data and metadata devices,
so that the metadata device can be discarded and the table can be reloaded
with a linear target pointing to the data device.
NOTE: the journal is deliberately not flushed when using the same device
for metadata and data, so that the journal replay code is tested.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Use version "2" in the superblock when data and metadata devices are
separate, so that the device is not accidentally read by older kernel
version.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Add the ability to store DM integrity metadata on a separate device.
This feature is activated with the option "meta_device:/dev/device".
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
A small refactoring. Add the variable ic->start to the result
returned by get_data_sector() and not in the callers. This is a
prerequisite for the commit that adds the ability to use an external
metadata device.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
dm-integrity locks a range of sectors to prevent concurrent I/O or journal
writeback. These locks were not fair - so that many small overlapping I/Os
could starve a large I/O indefinitely.
Fix this by making the range locks fair. The ranges that are waiting are
added to the list "wait_list". If a new I/O overlaps some of the waiting
I/Os, it is not dispatched, but it is also added to that wait list.
Entries on the wait list are processed in first-in-first-out order, so
that an I/O can't starve indefinitely.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Decouple how dm_integrity_map_continue() responds to being out of free
sectors and when add_new_range() fails.
This has no functional change, but helps prepare for the next commit.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Early alpha processors can't write a byte or short atomically - they
read 8 bytes, modify the byte or two bytes in registers and write back
8 bytes.
The modification of the variable "suspending" may race with
modification of the variable "failed". Fix this by changing
"suspending" to an int.
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Add a new class for dm-delay that delays flush requests. Previously,
flushes were delayed as writes, but it caused problems if the user
needed to create a device with one or a few slow sectors for the purpose
of testing - all flushes would be forwarded to this device and delayed,
and that skews the test results. Fix this by allowing to select 0 delay
for flushes.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
dm-delay has a lot of code that is repeated for delaying read and write
bios. Repetitive code is generally bad; refactor out the repetitive
code in preperation for adding another delay class for flush bios.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
More than one io_mode feature can be requested when creating a dm cache
device (as is: last one wins). The io_mode selections are incompatible
with one another, we should force them to be selected exclusively. Add
a counter to check for more than one io_mode selection.
Fixes: 629d0a8a1a ("dm cache metadata: add "metadata2" feature")
Signed-off-by: John Pittman <jpittman@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The get_seconds function is deprecated now since it returns a 32-bit
value that will eventually overflow, and we are replacing it throughout
the kernel with ktime_get_seconds() or ktime_get_real_seconds() that
return a time64_t.
bcache uses get_seconds() to read the current system time and store it in
the superblock as well as in uuid_entry structures that are user visible.
Unfortunately, the two structures in are still limited to 32 bits, so this
won't fix any real problems but will still overflow in year 2106. Let's
at least document that properly, in case we get an updated format in the
future it can be fixed. We still have a long time before the overflow
and checking the tools at https://github.com/koverstreet/bcache-tools
reveals no access to any of them.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fixes an error condition reported by checkpatch.pl which is caused by
assigning a variable in an if condition.
Signed-off-by: Florian Schmaus <flo@geekplace.eu>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fixes an error condition reported by checkpatch.pl which is caused by
assigning a variable in an if condition.
Signed-off-by: Florian Schmaus <flo@geekplace.eu>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Free the cache_set->flush_bree heap memory on journal free.
Signed-off-by: Wang Sheng-Hui <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fixes an error condition reported by checkpatch.pl which is caused by
assigning a variable in an if condition.
Signed-off-by: Florian Schmaus <flo@geekplace.eu>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
I attached several backend devices in the same cache set, and produced lots
of dirty data by running small rand I/O writes in a long time, then I
continue run I/O in the others cached devices, and stopped a cached device,
after a mean while, I register the stopped device again, I see the running
I/O in the others cached devices dropped significantly, sometimes even
jumps to zero.
In currently code, bcache would traverse each keys and btree node to count
the dirty data under read locker, and the writes threads can not get the
btree write locker, and when there is a lot of keys and btree node in the
registering device, it would last several seconds, so the write I/Os in
others cached device are blocked and declined significantly.
In this patch, when a device registering to a ache set, which exist others
cached devices with running I/Os, we get the amount of dirty data of the
device in an incremental way, and do not block other cached devices all the
time.
Patch v2: Rename some variables and macros name as Coly suggested.
Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch base on "[PATCH] bcache: finish incremental GC".
Since incremental GC would stop 100ms when front side I/O comes, so when
there are many btree nodes, if GC only processes constant (100) nodes each
time, GC would last a long time, and the front I/Os would run out of the
buckets (since no new bucket can be allocated during GC), and I/Os be
blocked again.
So GC should not process constant nodes, but varied nodes according to the
number of btree nodes. In this patch, GC is divided into constant (100)
times, so when there are many btree nodes, GC can process more nodes each
time, otherwise GC will process less nodes each time (but no less than
MIN_GC_NODES).
Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In GC thread, we record the latest GC key in gc_done, which is expected
to be used for incremental GC, but in currently code, we didn't realize
it. When GC runs, front side IO would be blocked until the GC over, it
would be a long time if there is a lot of btree nodes.
This patch realizes incremental GC, the main ideal is that, when there
are front side I/Os, after GC some nodes (100), we stop GC, release locker
of the btree node, and go to process the front side I/Os for some times
(100 ms), then go back to GC again.
By this patch, when we doing GC, I/Os are not blocked all the time, and
there is no obvious I/Os zero jump problem any more.
Patch v2: Rename some variables and macros name as Coly suggested.
Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently we calculate the total amount of flash only devices dirty data
by adding the dirty data of each flash only device under registering
locker. It is very inefficient.
In this patch, we add a member flash_dev_dirty_sectors in struct cache_set
to record the total amount of flash only devices dirty data in real time,
so we didn't need to calculate the total amount of dirty data any more.
Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The function name mentioned doesn't exist, and the code next to it
doesn't match the description either.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We immediately overwrite the biovec array, so instead just allocate
a new bio and copy over the disk, setor and size.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is no need to invoke release_inactive_stripe_list() with interrupts
disabled. All call sites, except raid5_release_stripe(), unlock
->device_lock and enable interrupts before invoking the function.
Make it consistent.
Cc: Shaohua Li <shli@kernel.org>
Cc: linux-raid@vger.kernel.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Shaohua Li <shli@fb.com>
Pull device mapper fix from Mike Snitzer:
"Fix DM writecache target to allow an optional offset to the start of
the data and metadata area.
This allows userspace tools (e.g. LVM2) to place a header and metadata
at the front of the writecache device for its use"
* tag 'for-4.18/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm writecache: support optional offset for start of device
Add and use a new op_stat_group() function for indexing partition stat
fields rather than indexing them by rq_data_dir() or bio_data_dir().
This function works similarly to op_is_sync() in that it takes the
request::cmd_flags or bio::bi_opf flags and determines which stats
should et updated.
In addition, the second parameter to generic_start_io_acct() and
generic_end_io_acct() is now a REQ_OP rather than simply a read or
write bit and it uses op_stat_group() on the parameter to determine
the stat group.
Note that the partition in_flight counts are not part of the per-cpu
statistics and as such are not indexed via this function. It's now
indexed by op_is_write().
tj: Refreshed on top of v4.17. Updated to pass around REQ_OP.
Signed-off-by: Michael Callahan <michaelcallahan@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Matias Bjorling <mb@lightnvm.io>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Alasdair Kergon <agk@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a part_stat_read_accum macro to genhd.h to read and sum across
field entries. For example to sum up the number read and write
sectors completed. In addition to being ar reasonable cleanup by
itself this will make it easier to add new stat fields in the future.
tj: Refreshed on top of v4.17.
Signed-off-by: Michael Callahan <michaelcallahan@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pointer bio is being assigned but is never used hence it is redundant
and can be removed.
Cleans up clang warning:
warning: variable 'bio' set but not used [-Wunused-but-set-variable]
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Shaohua Li <shli@fb.com>
If we close an array which resync thread is running,
then we don't need the node to send msg since another
node would launch the resync thread to continue the
rest works. Also send a message is time consuming,
we should avoid it.
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
When resync or recovery is happening in one node,
other nodes don't show the appropriate info now.
For example, when create an array in master node
without "--assume-clean", then assemble the array
in slave nodes, you can see "resync=PENDING" when
read /proc/mdstat in slave nodes. However, the info
is confusing since "PENDING" status is introduced
for start array in read-only mode.
We introduce RESYNCING_REMOTE flag to indicate that
resync thread is running in remote node. The flags
is set when node receive RESYNCING msg. And we clear
the REMOTE flag in following cases:
1. resync or recover is finished in master node,
which means slaves receive msg with both lo
and hi are set to 0.
2. node continues resync/recovery in recover_bitmaps.
3. when resync_finish is called.
Then we show accurate information in status_resync
by check REMOTE flags and with other conditions.
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
When one node leaves cluster or stops the resyncing
(resync or recovery) array, then other nodes need to
call recover_bitmaps to continue the unfinished task.
But we need to clear suspend_area later after other
nodes copy the resync information to their bitmap
(by call bitmap_copy_from_slot). Otherwise, all nodes
could write to the suspend_area even the suspend_area
is not handled by any node, because area_resyncing
returns 0 at the beginning of raid1_write_request.
Which means one node could write suspend_area while
another node is resyncing the same area, then data
could be inconsistent.
So let's clear suspend_area later to avoid above issue
with the protection of bm lock. Also it is straightforward
to clear suspend_area after nodes have copied the resync
info to bitmap.
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Add an optional parameter "start_sector" to allow the start of the
device to be offset by the specified number of 512-byte sectors. The
sectors below this offset are not used by the writecache device and are
left to be used for disk labels and/or userspace metadata (e.g. lvm).
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Pull MD fixes from Shaohua Li:
"Two small fixes for MD:
- an error handling fix from me
- a recover bug fix for raid10 from BingJing"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
md/raid10: fix that replacement cannot complete recovery after reassemble
MD: cleanup resources in failure
Currently device_supports_dax() just checks to see if the QUEUE_FLAG_DAX
flag is set on the device's request queue to decide whether or not the
device supports filesystem DAX. Really we should be using
bdev_dax_supported() like filesystems do at mount time. This performs
other tests like checking to make sure the dax_direct_access() path works.
We also explicitly clear QUEUE_FLAG_DAX on the DM device's request queue if
any of the underlying devices do not support DAX. This makes the handling
of QUEUE_FLAG_DAX consistent with the setting/clearing of most other flags
in dm_table_set_restrictions().
Now that bdev_dax_supported() explicitly checks for QUEUE_FLAG_DAX, this
will ensure that filesystems built upon DM devices will only be able to
mount with DAX if all underlying devices also support DAX.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Fixes: commit 545ed20e6d ("dm: add infrastructure for DAX support")
Cc: stable@vger.kernel.org
Acked-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
During assemble, the spare marked for replacement is not checked.
conf->fullsync cannot be updated to be 1. As a result, recovery will
treat it as a clean array. All recovering sectors are skipped. Original
device is replaced with the not-recovered spare.
mdadm -C /dev/md0 -l10 -n4 -pn2 /dev/loop[0123]
mdadm /dev/md0 -a /dev/loop4
mdadm /dev/md0 --replace /dev/loop0
mdadm -S /dev/md0 # stop array during recovery
mdadm -A /dev/md0 /dev/loop[01234]
After reassemble, you can see recovery go on, but it completes
immediately. In fact, recovery is not actually processed.
To solve this problem, we just add the missing logics for replacment
spares. (In raid1.c or raid5.c, they have already been checked.)
Reported-by: Alex Chen <alexchen@synology.com>
Reviewed-by: Alex Wu <alexwu@synology.com>
Reviewed-by: Chung-Chiang Cheng <cccheng@synology.com>
Signed-off-by: BingJing Chang <bingjingc@synology.com>
Signed-off-by: Shaohua Li <shli@fb.com>
