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  1. 30 8月, 2017 5 次提交
  3. 29 8月, 2017 8 次提交
  5. 26 8月, 2017 8 次提交
  7. 24 8月, 2017 15 次提交
  9. 23 8月, 2017 4 次提交
    • S
      nullb: badbblocks support · 2f54a613
      由 Shaohua Li 提交于 
      Sometime disk could have tracks broken and data there is inaccessable,
but data in other parts can be accessed in normal way. MD RAID supports
such disks. But we don't have a good way to test it, because we can't
control which part of a physical disk is bad. For a virtual disk, this
can be easily controlled.

This patch adds a new 'badblock' attribute. Configure it in this way:
echo "+1-100" > xxx/badblock, this will make sector [1-100] as bad
blocks.
echo "-20-30" > xxx/badblock, this will make sector [20-30] good

If badblocks are accessed, the nullb disk will return IO error. Other
parts of the disk can accessed in normal way.
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      2f54a613
    • S
      nullb: emulate cache · deb78b41
      由 Shaohua Li 提交于 
      Software must flush disk cache to guarantee data safety. To check if
software correctly does disk cache flush, we must know the behavior of
disk. But physical disk behavior is uncontrollable. Even software
doesn't do the flush, the disk probably does the flush. This patch tries
to emulate a cache in the test disk.

All write will go to a cache first, when the cache is full, we then
flush some data to disk storage. A flush request will flush all data of
the cache to disk storage. A FUA write will write to memory store
directly and revalidate data in cache. If there is a power failure (by
writing to power attribute, 'echo 0 > disk_name/power'), we discard all
data in the cache, but preserve the data in disk storage. Later we can
power on the disk again as usual (write 1 to 'power' attribute), then we
can check data integrity and very if software does everything correctly.

A new attribute 'cache_size' (in MB) is added to configure cache size.

Based on original patch from Kyungchan Koh
Signed-off-by: NKyungchan Koh <kkc6196@fb.com>
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      deb78b41
    • S
      nullb: bandwidth control · eff2c4f1
      由 Shaohua Li 提交于 
      In test, we usually expect controllable disk speed. For example, in a
raid array, we'd like some disks are fast and some are slow. MD RAID
actually has a feature for this. To test the feature, we'd like to make
the disk run in specific speed.

block throttling probably can be used for this purpose, but it requires
cgroup setup. Here we just implement a simple throttling mechanism in
the driver. There is slight fluctuation in the mechanism, but it's good
enough for test.

To configure the bandwidth cap, user sets the 'mbps' attribute. mbps is
MB/s.

Based on original patch from Kyungchan Koh
Signed-off-by: NKyungchan Koh <kkc6196@fb.com>
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      eff2c4f1
    • S
      nullb: support discard · 306eb6b4
      由 Shaohua Li 提交于 
      discard makes sense for memory backed disk. And also it's useful to test
if upper layer supports dicard correctly.

User configures 'discard' attribute to enable/disable dicard support.

Based on original patch from Kyungchan Koh
Signed-off-by: NKyungchan Koh <kkc6196@fb.com>
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      306eb6b4