rbd: expose the correct size of the device in sysfs

If an image was mapped to a snapshot, the size of the head version
would be shown. Protect capacity with header_rwsem, since it may
change.

Signed-off-by: Josh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit a51aa0c042fa39946dd017d5f91a073300a71577)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rbd: set image size when header is updated

The image may have been resized.

Signed-off-by: Josh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit 93a24e084d67ba2fcb9a4c289135825b623ec864)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rbd: use reference counting for the snap context

This prevents a race between requests with a given snap context and
header updates that free it. The osd client was already expecting the
snap context to be reference counted, since it get()s it in
ceph_osdc_build_request and put()s it when the request completes.

Also remove the second down_read()/up_read() on header_rwsem in
rbd_do_request, which wasn't actually preventing this race or
protecting any other data.

Signed-off-by: Josh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit d1d25646543134d756a02ffe4e02073faa761f2c)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rbd: send header version when notifying

Previously the original header version was sent. Now, we update it
when the header changes.

Signed-off-by: Josh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit a71b891bc7d77a070e723c8c53d1dd73cf931555)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ceph: tolerate (and warn on) extraneous dentry from mds

If the MDS gives us a dentry and we weren't prepared to handle it,
WARN_ON_ONCE instead of crashing.

Reported-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit 6c5e50fa614fea5325a2973be06f7ec6f1055316)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rbd: drop dev reference on error in rbd_open()

If a read-only rbd device is opened for writing in rbd_open(), it
returns without dropping the just-acquired device reference.

Fix this by moving the read-only check before getting the reference.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
(cherry picked from commit 340c7a2b2c9a2da640af28a8c196356484ac8b50)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ceph: propagate layout error on osd request creation

If we are creating an osd request and get an invalid layout, return
an EINVAL to the caller.  We switch up the return to have an error
code instead of NULL implying -ENOMEM.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit 6816282dab3a72efe8c0d182c1bc2960d87f4322)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: socket can close in any connection state

A connection's socket can close for any reason, independent of the
state of the connection (and without irrespective of the connection
mutex).  As a result, the connectino can be in pretty much any state
at the time its socket is closed.

Handle those other cases at the top of con_work().  Pull this whole
block of code into a separate function to reduce the clutter.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(cherry picked from commit 7bb21d68c535ad8be38e14a715632ae398b37ac1)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: report connection fault with warning

When a connection's socket disconnects, or if there's a protocol
error of some kind on the connection, a fault is signaled and
the connection is reset (closed and reopened, basically).  We
currently get an error message on the log whenever this occurs.

A ceph connection will attempt to reestablish a socket connection
repeatedly if a fault occurs.  This means that these error messages
will get repeatedly added to the log, which is undesirable.

Change the error message to be a warning, so they don't get
logged by default.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(cherry picked from commit 28362986f8743124b3a0fda20a8ed3e80309cce1)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: init osd->o_node in create_osd()

The red-black node node in the ceph osd structure is not initialized
in create_osd().  Because this node can be the subject of a
RB_EMPTY_NODE() call later on, we should ensure the node is
initialized properly for that.  Add a call to RB_CLEAR_NODE()
initialize it.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(cherry picked from commit f407731d12214e7686819018f3a1e9d7b6f83a02)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: init event->node in ceph_osdc_create_event()

The red-black node node in the ceph osd event structure is not
initialized in create_osdc_create_event().  Because this node can
be the subject of a RB_EMPTY_NODE() call later on, we should ensure
the node is initialized properly for that.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(cherry picked from commit 3ee5234df68d253c415ba4f2db72ad250d9c21a9)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: don't use rb_init_node() in ceph_osdc_alloc_request()

The red-black node in the ceph osd request structure is initialized
in ceph_osdc_alloc_request() using rbd_init_node().  We do need to
initialize this, because in __unregister_request() we call
RB_EMPTY_NODE(), which expects the node it's checking to have
been initialized.  But rb_init_node() is apparently overkill, and
may in fact be on its way out.  So use RB_CLEAR_NODE() instead.

For a little more background, see this commit:
    4c199a93 rbtree: empty nodes have no color"

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(cherry picked from commit a978fa20fb657548561dddbfb605fe43654f0825)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: register request before unregister linger

In kick_requests(), we need to register the request before we
unregister the linger request.  Otherwise the unregister will
reset the request's osd pointer to NULL.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(cherry picked from commit c89ce05e0c5a01a256100ac6a6019f276bdd1ca6)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: move linger requests sooner in kick_requests()

The kick_requests() function is called by ceph_osdc_handle_map()
when an osd map change has been indicated.  Its purpose is to
re-queue any request whose target osd is different from what it
was when it was originally sent.

It is structured as two loops, one for incomplete but registered
requests, and a second for handling completed linger requests.
As a special case, in the first loop if a request marked to linger
has not yet completed, it is moved from the request list to the
linger list.  This is as a quick and dirty way to have the second
loop handle sending the request along with all the other linger
requests.

Because of the way it's done now, however, this quick and dirty
solution can result in these incomplete linger requests never
getting re-sent as desired.  The problem lies in the fact that
the second loop only arranges for a linger request to be sent
if it appears its target osd has changed.  This is the proper
handling for *completed* linger requests (it avoids issuing
the same linger request twice to the same osd).

But although the linger requests added to the list in the first loop
may have been sent, they have not yet completed, so they need to be
re-sent regardless of whether their target osd has changed.

The first required fix is we need to avoid calling __map_request()
on any incomplete linger request.  Otherwise the subsequent
__map_request() call in the second loop will find the target osd
has not changed and will therefore not re-send the request.

Second, we need to be sure that a sent but incomplete linger request
gets re-sent.  If the target osd is the same with the new osd map as
it was when the request was originally sent, this won't happen.
This can be fixed through careful handling when we move these
requests from the request list to the linger list, by unregistering
the request *before* it is registered as a linger request.  This
works because a side-effect of unregistering the request is to make
the request's r_osd pointer be NULL, and *that* will ensure the
second loop actually re-sends the linger request.

Processing of such a request is done at that point, so continue with
the next one once it's been moved.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(cherry picked from commit ab60b16d3c31b9bd9fd5b39f97dc42c52a50b67d)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: always reset osds when kicking

When ceph_osdc_handle_map() is called to process a new osd map,
kick_requests() is called to ensure all affected requests are
updated if necessary to reflect changes in the osd map.  This
happens in two cases:  whenever an incremental map update is
processed; and when a full map update (or the last one if there is
more than one) gets processed.

In the former case, the kick_requests() call is followed immediately
by a call to reset_changed_osds() to ensure any connections to osds
affected by the map change are reset.  But for full map updates
this isn't done.

Both cases should be doing this osd reset.

Rather than duplicating the reset_changed_osds() call, move it into
the end of kick_requests().

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(cherry picked from commit e6d50f67a6b1a6252a616e6e629473b5c4277218)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: WARN, don't BUG on unexpected connection states

A number of assertions in the ceph messenger are implemented with
BUG_ON(), killing the system if connection's state doesn't match
what's expected.  At this point our state model is (evidently) not
well understood enough for these assertions to trigger a BUG().
Convert all BUG_ON(con->state...) calls to be WARN_ON(con->state...)
so we learn about these issues without killing the machine.

We now recognize that a connection fault can occur due to a socket
closure at any time, regardless of the state of the connection.  So
there is really nothing we can assert about the state of the
connection at that point so eliminate that assertion.

Reported-by: Ugis <ugis22@gmail.com>
Tested-by: Ugis <ugis22@gmail.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(cherry picked from commit 122070a2ffc91f87fe8e8493eb0ac61986c5557c)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: fix protocol feature mismatch failure path

We should not set con->state to CLOSED here; that happens in
ceph_fault() in the caller, where it first asserts that the state
is not yet CLOSED.  Avoids a BUG when the features don't match.

Since the fail_protocol() has become a trivial wrapper, replace
calls to it with direct calls to reset_connection().

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit 0fa6ebc600bc8e830551aee47a0e929e818a1868)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: fix osdmap decode error paths

Ensure that we set the err value correctly so that we do not pass a 0
value to ERR_PTR and confuse the calling code.  (In particular,
osd_client.c handle_map() will BUG(!newmap)).

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit 0ed7285e0001b960c888e5455ae982025210ed3d)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: avoid using freed osd in __kick_osd_requests()

If an osd has no requests and no linger requests, __reset_osd()
will just remove it with a call to __remove_osd().  That drops
a reference to the osd, and therefore the osd may have been free
by the time __reset_osd() returns.  That function offers no
indication this may have occurred, and as a result the osd will
continue to be used even when it's no longer valid.

Change__reset_osd() so it returns an error (ENODEV) when it
deletes the osd being reset.  And change __kick_osd_requests() so it
returns immediately (before referencing osd again) if __reset_osd()
returns *any* error.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
(cherry picked from commit 685a7555ca69030739ddb57a47f0ea8ea80196a4)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rbd: kill create_snap sysfs entry

Josh proposed the following change, and I don't think I could
explain it any better than he did:

    From: Josh Durgin <josh.durgin@inktank.com>
    Date: Tue, 24 Jul 2012 14:22:11 -0700
    To: ceph-devel <ceph-devel@vger.kernel.org>
    Message-ID: <500F1203.9050605@inktank.com>
    From: Josh Durgin <josh.durgin@inktank.com>


    Right now the kernel still has one piece of rbd management
    duplicated from the rbd command line tool: snapshot creation.
    There's nothing special about snapshot creation that makes it
    advantageous to do from the kernel, so I'd like to remove the
    create_snap sysfs interface.  That is,
	/sys/bus/rbd/devices/<id>/create_snap
    would be removed.

    Does anyone rely on the sysfs interface for creating rbd
    snapshots?  If so, how hard would it be to replace with:

	rbd snap create pool/image@snap

    Is there any benefit to the sysfs interface that I'm missing?

    Josh

This patch implements this proposal, removing the code that
implements the "snap_create" sysfs interface for rbd images.
As a result, quite a lot of other supporting code goes away.

[elder@inktank.com: commented out rbd_req_sync_exec() to avoid warning]

Suggested-by: Josh Durgin <josh.durgin@inktank.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
(based on commit 02cdb02ceab1f3dd9ac2bc899fc51f0e0e744782)