RepoMirrors/ceph
1
0
Fork 0
mirror of https://github.com/ceph/ceph synced 2025-01-11 21:50:26 +00:00
Code Issues Packages Projects Releases Wiki Activity

rgw_file: interned RGWFileHandle objects need parent refs

Browse Source 
RGW NFS fhcache/RGWFileHandle operators assume existence of the
full chain of parents from any object to the its fs_root--this is
a consequence of the weakly-connected namespace design goal, and
not a defect.

This change ensures the invariant by taking a parent ref when
objects are interned (when a parent ref is guaranteed).  Parent
refs are returned when objects are destroyed--essentially by the
invariant, such a ref must exist.

The extra ref is omitted when parent->is_root(), as that node is
not in the LRU cache.

Fixes: http://tracker.ceph.com/issues/18650

Signed-off-by: Matt Benjamin <mbenjamin@redhat.com>
This commit is contained in:
Matt Benjamin 2016-12-30 23:30:16 -05:00
parent 748f0a6fb9
commit 0e5299f3f4
2 changed files with 18 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
src/rgw/rgw_file.cc
View File

@ -716,6 +716,19 @@ namespace rgw {
} while (! (stop || shutdown));
} /* RGWLibFS::gc */
RGWFileHandle::~RGWFileHandle() {
if (parent && (! parent->is_root())) {
/* safe because if parent->unref causes its deletion,
* there are a) by refcnt, no other objects/paths pointing
* to it and b) by the semantics of valid iteration of
* fh_lru (observed, e.g., by cohort_lru<T,...>::drain())
* no unsafe iterators reaching it either--n.b., this constraint
* is binding oncode which may in future attempt to e.g.,
* cause the eviction of objects in LRU order */
(void) get_fs()->fh_lru.unref(parent, cohort::lru::FLAG_NONE);
}
}
void RGWFileHandle::encode_attrs(ceph::buffer::list& ux_key1,
ceph::buffer::list& ux_attrs1)
{

6
src/rgw/rgw_file.h
View File

@ -640,7 +640,7 @@ namespace rgw {
typedef cohort::lru::TreeX<RGWFileHandle, FhTree, FhLT, FhEQ, fh_key,
std::mutex> FHCache;
virtual ~RGWFileHandle() {}
virtual ~RGWFileHandle();
class Factory : public cohort::lru::ObjectFactory
{
@ -958,6 +958,10 @@ namespace rgw {
/* inserts, releasing latch */
fh_cache.insert_latched(fh, lat, RGWFileHandle::FHCache::FLAG_UNLOCK);
get<1>(fhr) |= RGWFileHandle::FLAG_CREATE;
/* ref parent (non-initial ref cannot fail on valid object) */
if (! parent->is_root()) {
(void) fh_lru.ref(parent, cohort::lru::FLAG_NONE);
}
goto out; /* !LATCHED */
} else {
lat.lock->unlock();