osd: fix the snapshot reads of evicted tiering pool

reset ssc->exsits in finish_ctx() if the ctx->cache_evict is true, and
the head is removed.

Fixes: #12748
Signed-off-by: Kefu Chai <kchai@redhat.com>
(cherry picked from commit b61f3e43f1c9d43daa0dedd7cbd0fe5787cbdfbb)

Merge pull request #6157 from dachary/wip-13040-hammer

common/Thread:pthread_attr_destroy(thread_attr) when done with it

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #6155 from dachary/wip-13171-hammer

objecter: cancellation bugs

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #6152 from dachary/wip-13233-hammer

mon: include min_last_epoch_clean as part of PGMap::print_summary and PGMap::dump

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #6146 from dachary/wip-13337-hammer

segfault in agent_work

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #6145 from dachary/wip-13338-hammer

filestore: fix peek_queue for OpSequencer

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #6144 from dachary/wip-13339-hammer

mon: check for store writeablility before participating in election

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #5891 from Abhishekvrshny/wip-13035-hammer

requeue_scrub when kick_object_context_blocked

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #5890 from Abhishekvrshny/wip-13037-hammer

hit set clear repops fired in same epoch as map change -- segfault since they fall into the new interval even though the repops are cleared

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #6322 from sponce/WIP-13210-hammer

tests : BACKPORT #13210 Fixed broken Makefiles after integration of ttng into rados

Reviewed-by: Kefu Chai <kchai@redhat.com>

Merge pull request #5810 from Abhishekvrshny/wip-12948-hammer

Heavy memory shuffling in rados bench

Reviewed-by: Kefu Chai <kchai@redhat.com>

Merge pull request #5530 from SUSE/wip-12587-hammer

FileStore calls syncfs(2) even it is not supported

Reviewed-by: Kefu Chai <kchai@redhat.com>

Merge pull request #5889 from Abhishekvrshny/wip-13042-hammer

ThreadPool add/remove work queue methods not thread safe

Reviewed-by: Josh Durgin <jdurgin@redhat.com>

Merge pull request #6151 from dachary/wip-13245-hammer

client nonce collision due to unshared pid namespaces

Reviewed-by: Josh Durgin <jdurgin@redhat.com>

Merge pull request #6159 from dachary/wip-13341-hammer

ceph upstart script rbdmap.conf incorrectly processes parameters

Reviewed-by: Loic Dachary <ldachary@redhat.com>

Merge pull request #6154 from dachary/wip-13195-hammer

should recalc the min_last_epoch_clean when decode PGMap

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #6132 from SUSE/wip-13307-hammer

dumpling incrementals do not work properly on hammer and newer

Reviewed-by: Loic Dachary <ldachary@redhat.com>

Merge pull request #6097 from dillaman/wip-13045-hammer

librbd: diff_iterate needs to handle holes in parent images

Reviewed-by: Loic Dachary <ldachary@redhat.com>

Merge pull request #6060 from XinzeChi/wip-hammer-outdata-set

bug fix: osd: avoid multi set osd_op.outdata in tier pool

Reviewed-by: Loic Dachary <ldachary@redhat.com>

Merge pull request #5897 from tchaikov/wip-12940-hammer

IO error on kvm/rbd with an erasure coded pool tier

Reviewed-by: Loic Dachary <ldachary@redhat.com>

Merge pull request #5787 from SUSE/wip-12923-hammer

logrotate reload error on Ubuntu 14.04

Reviewed-by: Loic Dachary <ldachary@redhat.com>

Merge pull request #5766 from dachary/wip-12590-hammer

ceph mds add_data_pool check for EC pool is wrong

Reviewed-by: Greg Farnum <gfarnum@redhat.com>

Merge pull request #5361 from ceph/wip-11786.hammer

mon: MonitorDBStore: get_next_key() only if prefix matches

Reviewed-by: Loic Dachary <ldachary@redhat.com>

0.94.5

Merge pull request #6348 from dillaman/wip-13567-hammer

librbd: potential assertion failure during cache read

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #6362 from liewegas/wip-shut-up-osd-hammer

osd/ReplicatedPG: remove stray debug line

Reviewed-by: Loic Dachary <ldachary@redhat.com>

osd/ReplicatedPG: remove stray debug line

This snuck in

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit ff9600a6cef613d40e875597b6392778df1bb04c)

librbd: potential assertion failure during cache read

It's possible for a cache read from a clone to trigger a writeback if a
previous read op determined the object doesn't exist in the clone,
followed by a cached write to the non-existent clone object, followed
by another read request to the same object.  This causes the cache to
flush the pending writeback ops while not holding the owner lock.

Fixes: #13559
Backport: hammer
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit 4692c330bd992a06b97b5b8975ab71952b22477a)

tests: reproduce crash during read-induced CoW

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit 382219b6bba09156f8cf3d420c6348738e7ed4c6)

Merge pull request #6330 from dachary/wip-13550-hammer

qemu workunit refers to apt-mirror.front.sepia.ceph.com

Reviewed-by: Jason Dillaman <dillaman@redhat.com>

radosstriper : Fixed broken Makefiles after integration of lttng

Fixes: #13210, backport of #6322 into hammer
Signed-off-by: Sebastien Ponce <sebastien.ponce@cern.ch>

qa: Use public qemu repo

This would allow some external tests outside of sepia lab

Signed-off-by: Yuan Zhou <yuan.zhou@intel.com>
(cherry picked from commit 4731c1e35539c9506ff3fe3141553fad099d0eee)

0.94.4

Merge pull request #6287 from jcsp/wip-test-fixes

git path backports for hammer

use git://git.ceph.com

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 34c467ba06345eacd2fd0e79c162dfd0b22f0486)

qa: http://ceph.com/qa -> http://download.ceph.com/qa

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit d4d65fbd6ad15320339751c604613ac63511e645)

Merge pull request #6161 from dachary/wip-13227-hammer

With root as default user, unable to have multiple RGW instances running

Reviewed-by: Sage Weil <sage@redhat.com>
Reviewed-by: Yehuda Sadeh <ysadehwe@redhat.com>
Reviewed-by: Ken Dreyer <kdreyer@redhat.com>

init-radosgw.sysv: remove

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 9d8c115b0ab05cfc1db6670d1d367737e61fe0ea)

Merge pull request #6166 from dachary/wip-13046-hammer

RGW : setting max number of buckets for user via ceph.conf option

Merge pull request #6039 from ceph/wip-13015-hammer

rgw: don't preserve acls when copying object

Merge pull request #6042 from dreamhost/wip-hammer-crossftp

rgw: remove trailing :port from host for purposes of subdomain matching

Merge pull request #6160 from dachary/wip-13228-hammer

rgw: segments are read during HEAD on Swift DLO

Merge pull request #6162 from dachary/wip-13226-hammer

Keystone Fernet tokens break auth

Merge pull request #6163 from dachary/wip-13054-hammer

rgw: region data still exist in region-map after region-map update

Merge pull request #6164 from dachary/wip-13053-hammer

rgw: GWWatcher::handle_error -> common/Mutex.cc: 95: FAILED assert(r == 0)

Merge pull request #5718 from dachary/wip-12859-hammer

testGetContentType and testHead failed

Merge pull request #5860 from lebauce/wip-12960-hammer

rgw: add delimiter to prefix only when path is specified

Merge pull request #6165 from dachary/wip-13052-hammer

rgw: init_rados failed leads to repeated delete

Merge pull request #6201 from dachary/wip-13410-hammer

TEST_crush_rule_create_erasure consistently fails on i386 builder

Reviewed-by: Kefu Chai <kchai@redhat.com>

Merge pull request #5885 from Abhishekvrshny/wip-13034-hammer

osd: copy-from doesn't preserve truncate_{seq,size}

Reviewed-by: Sage Weil <sage@redhat.com>

tests: robust test for the pool create crushmap test

The test that goes with f1e86be589803596e86acc964ac5c5c03b4038d8 to
verify that a bugous crush ruleset will prevent the creation of a pool
trying to use it was fragile. I depends on the implementation of the
erasure code lrc plugin and turns out to not work on i386.

The test is modified to use a fake crushtool that always returns false
and validate that it prevents the creation of a pool, which demonstrate
it is used for crushmap validation prior to the pool creation.

http://tracker.ceph.com/issues/12419 Fixes: #12419

Signed-off-by: Loic Dachary <ldachary@redhat.com>
(cherry picked from commit e47903727b5d53f795014bf29b417d357f2bd65a)

librbd: invoking RBD::open twice will leak memory

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit a5e88fcf11ebb16d4a1405b21cf6f895b37f185e)

Merge pull request #6192 from dachary/wip-13401-hammer

mon: fix crush testing for new pools

Reviewed-by: Sage Weil <sage@redhat.com>

crush/CrushTester: test fewer inputs when running crushtool

If there are a lot of crush rules (say, 100) then the test can
take a long time.  100 values per rule should be enough to catch
most issues.

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 0f82f461b33d93d868e185912a2c7e4074d06900)

Conflicts:
src/crush/CrushTester.cc
  in hammer the crushtool validation is via a shell
       and not via an internal subprocess utility

tests: update to match crushmap validation message

http://tracker.ceph.com/issues/13182 Fixes: #13182

Signed-off-by: Loic Dachary <ldachary@redhat.com>
(cherry picked from commit 21a1e75d8a7bad89a48cd9d36902c5d609be5015)

Conflicts:
qa/workunits/cephtool/test.sh
  the test structure in hammer is different, adapt
  the relevant test.

mon/OSDMonitor: fix crush injection error message

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 1b3090d50e5bd5ca3e6e396b23d2d9826896c718)

Conflicts:
src/mon/OSDMonitor.cc
  hammer has a separate error message for EINTR
  which is in the context of the fix for error message

mon/OSDMonitor: only test crush ruleset for the newly created pool

Otherwise, we test *all* crush rules.. which might be a lot, and
which is a big waste of time and effort.

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 524b0bdcc45c2f4b95f2239c988e93250f337f3d)

Conflicts:
src/mon/OSDMonitor.cc : trivial resolution

crush/CrushTester: allow testing by ruleset

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit aa238e5ed50f44a94caf84567267e4f6be8732a2)

Conflicts:
src/crush/CrushTester.cc
          in hammer the crushtool validation is via a shell
  and not via an internal subprocess utility
src/tools/crushtool.cc
  ceph_argparse_withint is preferred to ceph_argparse_witharg

Merge pull request #5887 from Abhishekvrshny/wip-13044-hammer

LibCephFS.GetPoolId failure

Reviewed-by: Sage Weil <sage@redhat.com>

Merge pull request #6172 from dachary/wip-13354-hammer

qa/workunits/cephtool/test.sh: don't assume crash_replay_interval=45

Reviewed-by: Loic Dachary <ldachary@redhat.com>

qa/workunits/cephtool/test.sh: don't assume crash_replay_interval=45

e.g., it's 5 in teuthology's ceph.conf.

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 80b7237e5e74d12b9d8b1f96ea535c96bdff9c6f)

rgw:add --reset-regions for regionmap update

Fixes: #12964
Signed-off-by: Weijun Duan <duanweijun@h3c.com>
(cherry picked from commit 95685c19d6f1eab50b903e61273b5351bedc2980)

Conflicts:
src/rgw/rgw_admin.cc: usage is on cerr in hammer, not cout
        src/test/cli/radosgw-admin/help.t: remove extra empty line

Merge pull request #6156 from dachary/wip-13170-hammer

doc: update docs to point to download.ceph.com

Reviewed-by: Abhishek Varshney <abhishek.varshney@flipkart.com>

use simplifed messenger constructor for clients

This is all mechanical except the calculation of the nonce, which is
now always randomized for clients.

Fixes: #13032
Signed-off-by: Josh Durgin <jdurgin@redhat.com>
(cherry picked from commit a3a8c85b79afef67681c32c57b591c0e0a87a349)

msg: add simplified messenger constructor

Several callers create messengers using exactly the same parameters:

- reading the ms type from cct that is also passed in
- a default entity_name_t::CLIENT
- the default features

Additionally, the nonce should be randomized and not depend on
e.g. pid, as it does in several callers now. Clients running in
containers can easily have pid collisions, leading to hangs, so
randomize the nonce in this simplified constructor rather than
duplicating that logic in every caller.

Daemons have meaningful entity_name_ts, and monitors currently depend
on using 0 as a nonce, so make this simple constructer
client-specific.

Related: #13032
Signed-off-by: Josh Durgin <jdurgin@redhat.com>
(cherry picked from commit e3785b0b5fbff870adbd5f121021b671912386cf)

Conflicts:
   src/msg/Messenger.cc: Messenger::create only has 5 arguments in
   hammer. Since the last one is zero, it does not change the
   semantic.

rgw : setting max number of buckets for users via ceph.conf option

This patch adds a new option "rgw_user_max_buckets" for setting
max number of buckets for users via ceph.conf.

Fixes #12714

Signed-off-by: Vikhyat Umrao <vumrao@redhat.com>
(cherry picked from commit f65267c96cbd4cd25036b6bf399692e77bbb9436)

Conflicts:
src/rgw/rgw_admin.cc: usage is on cerr in hammer, not cout

rgw: init_rados failed leads to repeated delete

Fixes: #12978
Signed-off-by: Xiaowei Chen <chen.xiaowei@h3c.com>
(cherry picked from commit ab4232baa7bcc86e90746e13312ac9bda1772872)

rgw: delete finisher only after finalizing watches

Fixes: #12208
The watch error path might try to schedule a finisher work, delete finisher
only after watch destruction.

Signed-off-by: Yehuda Sadeh <yehuda@redhat.com>
(cherry picked from commit 97aed59fb9e865d30d31d2b7f4e93fc9727c96fa)

rgw: be more flexible with iso8601 timestamps

make parsing 8601 more flexible by not restricting the length of seconds
to 5, this allows timestamp to be specified both as ms or us. Newer
keystone backends such as fernet token backend default to microseconds
when publishing iso8601 timestamps, so this allows these timestamps to
be allowed when specifying the token expiry time.

Fixes: #12761
Reported-by: Ian Unruh <ianunruh@gmail.com>
Signed-off-by: Abhishek Lekshmanan <abhishek.lekshmanan@ril.com>
(cherry picked from commit 136242b5612b8bbf260910b1678389361e86d22a)

init-radosgw: specify pid file to start-stop-daemon

This fixes restart when multiple instances are running.

Fixes: #12407
Tested-by: Pavan Rallabhandi <pavan.rallabhandi@sandisk.com>
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit e17c8e1a7a06db0e2680dedc7e954021610320d1)

rgw: fix radosgw start-up script.

radosgw init script is unable to start radosgw daemon.
as it is relies on requiretty being disabled.
once init script start this daemon with sudo it fails
to start the daemon.

changing 'sudo' to 'su', it will fix this issue and
will also help running radosgw daemon with our new
"ceph" UID project.

Fixes: #10927
Signed-off-by: Vikhyat Umrao <vumrao@redhat.com>
(cherry picked from commit c83542296aeb8f5dd96f5d9e09327e7a89370742)

init-radosgw: unify init-radosgw[.sysv]

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 1c45f512a91ee49e9253ba6fd3857af9bd2ae57a)

init-radosgw: look in /var/lib/ceph/radosgw

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit a4bb992426b39188e750fce9198052ca0d510117)

doc: rgw: fix typo in comments

Signed-off-by: Nathan Cutler <ncutler@suse.cz>
(cherry picked from commit 05cf0db22dc3a9cb2bf4b86b8f240683c23f41ac)

rgw: init script waits until the radosgw stops

Fixes: #11140
Init script waits in stop action until the radowgw daemons stop.

Signed-off-by: Dmitry Yatsushkevich <dyatsushkevich@mirantis.com>
(cherry picked from commit 1cca0c1e91a1e18f82f4d22855e96b2fc947f5ea)

rgw: don't read actual data on user manifest HEAD

Fixes: #12780
We unconditionally read all the data, which is not needed
when doing HEAD operation on user manifest objects.

Signed-off-by: Yehuda Sadeh <yehuda@redhat.com>
Signed-off-by: Radoslaw Zarzynski <rzarzynski@mirantis.com>
(cherry picked from commit 4a8b08d1dd2511e28e999f1625103fb919fb5465)

init-rbdmap: fix CMDPARAMS

Fixes: #13214
Reported-by: Wyllys Ingersoll <wyllys.ingersoll@keepertech.com>
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 02113ac449cd7631f1c9a3840c94bbf253c052bd)

Common/Thread: pthread_attr_destroy(thread_attr) when done with it
When a thread attributes object is no longer required, it should be destroyed using the
pthread_attr_destroy() function. Destroying a thread attributes object has no effect on threads that were created using that object.

Fixes: #12570
Signed-off-by: zqkqkz zheng.qiankun@h3c.com
(cherry picked from commit 9471bb838a420ef5f439191d87e5388fecccb9e6)

Thread.cc: remove malloc/free pair

There's no need for mallocing pthread_attr_t in Thread::try_create(),
it can be located on stack as it is freed in same function. This reduces
pressure put on memory manager.

Signed-off-by: Piotr Dałek <piotr.dalek@ts.fujitsu.com>
(cherry picked from commit 614ac0f4e375f3dd008c8937d3f89f6005d6e0a0)

doc: remove mention of ceph-extra as a requirement

Signed-off-by: Alfredo Deza <adeza@redhat.com>
(cherry picked from commit a6f07e9fa3bd5e50a2d8cfa387b44a39d383fa65)

doc: remove ceph-extras

Signed-off-by: Alfredo Deza <adeza@redhat.com>
(cherry picked from commit c0ef84fd22aac58b6ec8e58eb4f8dffed306d39e)

doc: correct links to download.ceph.com

Signed-off-by: Alfredo Deza <adeza@redhat.com>
(cherry picked from commit 387d7800359154950431d0984c756f43f21dd9b4)

doc: Added "Hammer" in the list of major releases.

Fixes: #12771
Signed-off-by: ritz303 <ritz_303@yahoo.com>
(cherry picked from commit 582f0f64455079290ad3b4ae7338b716e170911f)

osdc/Objecter: optimize Objecter::tick.

Set bool value is better than insert same value into set<>.

Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>
(cherry picked from commit ee204044d9e69ea44b533c05cec154974039264c)

osdc/Objecter: remove the unuseful code.

Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>
(cherry picked from commit 80f10e3e59dadda2dca4eb62c68af972b701b316)

osdc/Objecter: Don't forget call _op_cancel_map_check when cancel linger op.

Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>
(cherry picked from commit 7cc963b1c6ab37bf33638dc6eca7848d93f7908f)

osdc/Objecter: In _cancel_linger_op, it should make num_unacked/num_committed decrease.

Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>
(cherry picked from commit 36b62710ddef0ffaee25837a92ca1ac9b353ff05)

osdc/Objeter: When cancel op, decrease num_unacked/num_uncommitted.

Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>
(cherry picked from commit 064e8585a04edb3d87b38db6bed03e965cfcb359)

osdc/Objecter: For func op_cancel_writes it can directly call op_cancel.

Becasue we get write-lock of rwlock, so it is safe to call op_cancel
rather than _op_canchel(homeless_session for this case don't met).

Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>
(cherry picked from commit e4ce619fe17a7a9dfc18e6af0b84928aa2d88c00)

Conflicts:
      src/osdc/Objecter.cc: the last if (found) was incorrectly
      implemented as if (to_cancel.size()) after hammer. The
      conflict is because the patch tries to revert an incorrect
      if (to_cancel.size()) which is not in hammer.

Objecter: Take RLocker when call is_active.

Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>
(cherry picked from commit 89f0112e001a2561f9a5cd705898d43c8909501f)

mon/PGMap: calc min_last_epoch_clean when decode

Fixes: #13112
Signed-off-by: Kefu Chai <kchai@redhat.com>
(cherry picked from commit d0ac68bf1785b330f3202d924c2203ace9393fe6)

osd: print min_last_epoch_clean along with pg dump

Fixes: 13198
Signed-off-by: Guang Yang <yguang@yahoo-inc.com>
(cherry picked from commit f5359f2314ce3e76ed446c01889dd23550c3ac36)

OSDService::agent_entry: don't use PG::operator<< without pg lock

Fixes: #13199
Signed-off-by: Samuel Just <sjust@redhat.com>
(cherry picked from commit d422f2820d5beee15117e166546a6386120e0349)

Conflicts:
src/osd/OSD.cc: trivial resolution

filestore: fix peek_queue for OpSequencer

Fixes: #13209
Signed-off-by: Xinze Chi <xinze@xsky.com>
(cherry picked from commit 5f7b3f5cde779f1300a35a04df2cdb1299f55472)

mon/Elector: do a trivial write on every election cycle

Currently we already do a small write when the *first* election in
a round happens (to update the election epoch).  If the backend
happens to fail while we are already in the midst of elections,
however, we may continue to call elections without verifying we
are still writeable.

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit ef909ccbdc303cce8a39edef255325127832ff16)

mon/MonitorDBStore: assert/crash if there is a write error

Do this globally intead of relying on teh zillion mon callers to
check the error code.  There are no cases where we want to
tolerate a commit failure.

Fixes: #13089
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 2fb7b1f0e33ada7c9a1be3de2f7708eb0760fcef)

OSDMap: fill in known encode_features where possible

Otherwise, if we get an incremental from hammer (struct_v = 6) we will
encode the full map as if it were before CEPH_FEATURE_PGID64, which
was actually pre-argonaut.  Similarly, if struct_v >= 7, we know it
was encoded with CEPH_FEATURE_OSDMAP_ENC.

Fixes: #13234
Backport: hammer
Signed-off-by: Samuel Just <sjust@redhat.com>
(cherry picked from commit 04679c5451e353c966f6ed00b33fa97be8072a79)

rgw: set default value for env->get() call

Fixes: #13239
This fixes a regression introduced at commit abe4ec293d08b0314bf5c081ace2456073f3a22c.
The host var is a string, env->get() returns a char pointer, shouldn't
pass in NULL.

Signed-off-by: Yehuda Sadeh <yehuda@redhat.com>
(cherry picked from commit 0d5730efc0054334897315dc23ba04f30548e36e)
Signed-off-by: Robin H. Johnson <robin.johnson@dreamhost.com>

librbd: diff_iterate needs to handle holes in parent images

If a clone's parent image snapshot includes a discarded extent,
this was previously causing an assert failure.  Instead, ignore
any discard holes in the parent image.

Fixes: #12885
Backport: hammer
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit 3ccc3bb4bd35e57209852d460633e371b4d004e2)

 Conflicts:
src/librbd/DiffIterate.cc : file doesn't exist in hammer, logic is in internal.cc

tests: new test case for librbd diff_iterate over discard extents

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit d5650c9cf85188efa73b279c8f4e4723fa475308)

Conflicts:
    src/test/librbd/test_librbd.cc : diff_iterate2 doesn't exist in hammer