os/bluestore:Fix size calculation in bitallocator

[chhabaramesh]

Internal size and external size are different got Bitallocator.
Hence creating separate function.

Signed-off-by: Ramesh Chander Ramesh.Chander@sandisk.com

[chhabaramesh]

Passed all three tests:

1. unit test bit_alloc
2. unit test alloc
3. ceph_test_objectstore:

[==========] Running 8 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 8 tests from Allocator/AllocTest

....
[----------] Global test environment tear-down
[==========] 8 tests from 1 test case ran. (0 ms total)
[ PASSED ] 8 tests.

[==========] Running 6 tests from 2 test cases.
[----------] Global test environment set-up.
[----------] 5 tests from BitAllocator

.....
[ OK ] BitAllocator.test_bmap_alloc_concurrent (9344 ms)
[----------] 5 tests from BitAllocator (71344 ms total)

[----------] 1 test from BitAllocator2
[ RUN ] BitAllocator2.test_bmap_alloc
[ OK ] BitAllocator2.test_bmap_alloc (0 ms)
[----------] 1 test from BitAllocator2 (0 ms total)

[----------] Global test environment tear-down
[==========] 6 tests from 2 test cases ran. (71344 ms total)
[ PASSED ] 6 tests.

2016-07-20 23:25:35.969472 7ffff7fd4680 -1 WARNING: the following dangerous and experimental features are enabled: *
[==========] Running 236 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 236 tests from ObjectStore/StoreTest
[ RUN ] ObjectStore/StoreTest.collect_metadata/0

......
==> rm -r store_test_temp_dir
[ OK ] ObjectStore/StoreTest.TooManyBlobsTest/3 (100 ms)
[----------] 236 tests from ObjectStore/StoreTest (1315409 ms total)

[----------] Global test environment tear-down
[==========] 236 tests from 1 test case ran. (1315409 ms total)
[ PASSED ] 236 tests.

[chhabaramesh]

@markhpc , this is fix for unit test case failure for allocator.

[xiexingguo]

looks good to me:-)

[xiexingguo]

One more question:

this adjustment is required to return correct blocks in stats.

How does this fix also address this?

[tchaikov]

could be a const method.

[chhabaramesh]

now since we have separate function for get_free in BitMapAllocator, caller of get_free will not get m_extra_blocks. Rest internal function will consider m_extra_blocks.

allocator::get_free is used by bluestore stats.

[xiexingguo]

Got it. Thanks for the explanation.

[tchaikov]

could use auto here.

[chhabaramesh]

@tchaikov , addressed all comments and tested again.

[dmick]

This definitely should have been two commits. @chhabaramesh, please try to limit commits to one issue and make them smaller. @tchaikov, please try to request that in review.

[chhabaramesh]

@dmick sure, will do suggested for future pull requests.

[tchaikov]

@dmick sure, will do. thanks for the reminder.