Robustify ceph-rbdnamer and adapt udev rules

Below is a patch which makes the ceph-rbdnamer script more robust and
fixes a problem with the rbd udev rules.

On our setup we encountered a symlink which was linked to the wrong rbd:

  /dev/rbd/mypool/myrbd -> /dev/rbd1

While that link should have gone to /dev/rbd3 (on which a
partition /dev/rbd3p1 was present).

Now the old udev rule passes %n to the ceph-rbdnamer script, the problem
with %n is that %n results in a value of 3 (for rbd3), but in a value of
1 (for rbd3p1), so it seems it can't be depended upon for rbdnaming.

In the patch below the ceph-rbdnamer script is made more robust and it
now it can be called in various ways:

  /usr/bin/ceph-rbdnamer /dev/rbd3
  /usr/bin/ceph-rbdnamer /dev/rbd3p1
  /usr/bin/ceph-rbdnamer rbd3
  /usr/bin/ceph-rbdnamer rbd3p1
  /usr/bin/ceph-rbdnamer 3

Even with all these different styles of calling the modified script, it
should now return the same rbdname. This change "has" to be combined
with calling it from udev with %k though.

With that fixed, we hit the second problem. We ended up with:

  /dev/rbd/mypool/myrbd -> /dev/rbd3p1

So the rbdname was symlinked to the partition on the rbd instead of the
rbd itself. So what probably went wrong is udev discovering the disk and
running ceph-rbdnamer which resolved it to myrbd so the following
symlink was created:

  /dev/rbd/mypool/myrbd -> /dev/rbd3

However partitions would be discovered next and ceph-rbdnamer would be
run with rbd3p1 (%k) as parameter, resulting in the name myrbd too, with
the previous correct symlink being overwritten with a faulty one:

  /dev/rbd/mypool/myrbd -> /dev/rbd3p1

The solution to the problem is in differentiating between disks and
partitions in udev and handling them slightly differently. So with the
patch below partitions now get their own symlinks in the following style
(which is fairly consistent with other udev rules):

  /dev/rbd/mypool/myrbd-part1 -> /dev/rbd3p1

Please let me know any feedback you have on this patch or the approach
used.

Regards,
Pascal de Bruijn
Unilogic B.V.

Signed-off-by: Pascal de Bruijn <pascal@unilogicnetworks.net>
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Merge branch 'next'
log: simplify log logic a bit

Whether an entry is eligible to log/dump is independent of the channel it
is sent to.  Some channels impose additional restrictions.

Signed-off-by: Sage Weil <sage@inktank.com>
doc: discuss choice of pg_num

Signed-off-by: Sage Weil <sage@inktank.com>
doc/internals/osd_internals: fix indentation errors

Signed-off-by: Samuel Just <sam.just@inktank.com>
doc/dev: add osd_internals to toc

Signed-off-by: Samuel Just <sam.just@inktank.com>
osd: default 'osd_preserve_trimmed_log = false'

This option makes the osd skip zeroing old trimmed regions of the log.  The
data is never read, since the xattrs indicate which part of the log is
valid.  We've never actually used this to debug a problem, and it consumes
space, so let's disable it.

Signed-off-by: Sage Weil <sage@inktank.com>
librados: simplify locking slightly

No reason to hold mylock_all here.

Signed-off-by: Sage Weil <sage@inktank.com>
doc/dev/osd_internals: add newlines before numbered lists

Signed-off-by: Samuel Just <sam.just@inktank.com>
OSD: handle_osd_ping: use service->get_osdmap()

This way, we avoid grabbing the map_lock.  Furthermore,
get curmap at the beginning of the method to ensure that
we send the message using the same map used to check
is_up.

This should also fix #2798, which was caused by
an osd being marked up between service.get_osdmap()
and OSD::osdmap.

Signed-off-by: Samuel Just <sam.just@inktank.com>
OSD: use service.get_osdmap() in heartbeat(), don't grab map_lock

service.get_osdmap() gives us sufficiently consist
access to the map state.

Signed-off-by: Samuel Just <sam.just@inktank.com>
client: fix leak of client_lock when not initialized

Backport: argonaut
Signed-off-by: Sage Weil <sage@inktank.com>
client: fix readdir locking

Several of the readdir-related methods were not taking client_lock.

Fixes: #1737
Backport: argonaut
Signed-off-by: Sage Weil <sage@inktank.com>
Merge branch 'next'
doc: Overhauled Swift API documentation.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: favicon.ico should be new Ceph icon.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Fixed heading text.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
ObjectCacher: fix cache_bytes_hit accounting

Misses are not hits!

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
qa/workunits/suites/pjd.sh: bash -x

This will let us see what test is failing, exactly, and what its inputs
were.  Hoping to help find #2187.

Signed-off-by: Sage Weil <sage@inktank.com>
OSD: publish_map in init to initialize OSDService map

Other areas rely on OSDService::get_map() to function, possibly before
activate_map is first called.  In particular, with handle_osd_ping,
not initializing the map member results in:

ceph version 0.48argonaut-413-g90ddc5a (commit:90ddc5ae51627e7656459085d7e15105c8b8316d)
 1: /tmp/cephtest/binary/usr/local/bin/ceph-osd() [0x71ba9a]
 2: (()+0xfcb0) [0x7fcd8243dcb0]
 3: (OSD::handle_osd_ping(MOSDPing*)+0x74d) [0x5dbdfd]
 4: (OSD::heartbeat_dispatch(Message*)+0x22b) [0x5dc70b]
 5: (SimpleMessenger::DispatchQueue::entry()+0x92b) [0x7b5b3b]
 6: (SimpleMessenger::dispatch_entry()+0x24) [0x7b6914]
 7: (SimpleMessenger::DispatchThread::entry()+0xd) [0x7762fd]
 8: (()+0x7e9a) [0x7fcd82435e9a]
 9: (clone()+0x6d) [0x7fcd809ea4bd]
 NOTE: a copy of the executable, or `objdump -rdS <executable>` is needed to interpret this.

Signed-off-by: Samuel Just <sam.just@inktank.com>