rbd: fetch object order before using it

rbd_dev_v2_header_onetime() fetches striping information, and
checks whether the image can be read by compariing the stripe unit
to the object size. It determines the object size by shifting
the object order, which is 0 at this point since it has not been
read yet. Move the call to get the image size and object order
before rbd_dev_v2_header_onetime() so it is set before use.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
rbd: Use min_t() to fix comparison of distinct pointer types warning

drivers/block/rbd.c: In function ‘zero_pages’:
drivers/block/rbd.c:1102: warning: comparison of distinct pointer types lacks a cast

Remove the hackish casts and use min_t() to fix this.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Alex Elder <elder@inktank.com>
ceph: fix up comment for ceph_count_locks() as to which lock to hold

Signed-off-by: Jim Schutt <jaschut@sandia.gov>
Reviewed-by: Alex Elder <elder@inktank.com>
rbd: drop original request earlier for existence check

The reference to the original request dropped at the end of
rbd_img_obj_exists_callback() corresponds to the reference taken
in rbd_img_obj_exists_submit() to account for the stat request
referring to it.  Move the put of that reference up right after
clearing that pointer to make its purpose more obvious.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
ceph: improve error handling in ceph_mdsmap_decode

This patch makes the following improvements to the error handling
in the ceph_mdsmap_decode function:

- Add a NULL check for return value from kcalloc
- Make use of the variable err

Signed-off-by: Emil Goode <emilgoode@gmail.com>
Signed-off-by: Sage Weil <sage@inktank.com>
ceph: tidy ceph_mdsmap_decode() a little

I introduced a new temporary variable "info" instead of
"m->m_info[mds]".  Also I reversed the if condition and pulled
everything in one indent level.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Alex Elder <elder@inktank.com>
rbd: wait for safe callback for write requests

When a request is sent to the osd, the sender can indicate what
"level" of completion desired before the request is acknowledged.
There will always be at least an acknowledgement sent to indicate
the osd had received the message.  But for a write request the
sender may request that the acknowledgement indicate when the write
operation is durable on the osd.  The osd marks a response with the
ONDISK flag to signal this in its acknowledgement.

When a request is acknowledged a callback function is run and an
event is completed that a caller can wait for.  When the ONDISK flag
is set in an acknowledgement, an additional callback is used to
allow the caller to record when a request has been sent to an osd
(making it "unsafe"), and when an acknowledgement indicating such a
request has been made durable on the osd (so it is no longer
unsafe).  A "safe completion" is signaled to unblock any waiters.

With that as background...

Currently the rbd client waits only for the acknowledgement response
for all requests, which isn't safe for writes.  Fix that by defining
and using a different callback function that marks write requests
done only when the ONDISK notification arrives.

This resolves:
    http://tracker.ceph.com/issues/5146

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
libceph: add lingering request reference when registered

When an osd request is set to linger, the osd client holds onto the
request so it can be re-submitted following certain osd map changes.
The osd client holds a reference to the request until it is
unregistered.  This is used by rbd for watch requests.

Currently, the reference is taken when the request is marked with
the linger flag.  This means that if an error occurs after that
time but before the the request completes successfully, that
reference is leaked.

There's really no reason to take the reference until the request is
registered in the the osd client's list of lingering requests, and
that only happens when the lingering (watch) request completes
successfully.

So take that reference only when it gets registered following
succesful completion, and drop it (as before) when the request
gets unregistered.  This avoids the reference problem on error
in rbd.

Rearrange ceph_osdc_unregister_linger_request() to avoid using
the request pointer after it may have been freed.

And hold an extra reference in kick_requests() while handling
a linger request that has not yet been registered, to ensure
it doesn't go away.

This resolves:
    http://tracker.ceph.com/issues/3859

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
rbd: flush dcache after zeroing page data

Neither zero_bio_chain() nor zero_pages() contains a call to flush
caches after zeroing a portion of a page.  This can cause problems
on architectures that have caches that allow virtual address
aliasing.

This resolves:
    http://tracker.ceph.com/issues/4777

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
rbd: clean up a few things in the refresh path

This includes a few relatively small fixes I found while examining
the code that refreshes image information.

This resolves:
    http://tracker.ceph.com/issues/5040

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
rbd: protect against duplicate client creation

If more than one rbd image has the same ceph cluster configuration
(same options, same set of monitors, same keys) they normally share
a single rbd client.

When an image is getting mapped, rbd looks to see if an existing
client can be used, and creates a new one if not.

The lookup and creation are not done under a common lock though, so
mapping two images concurrently could lead to duplicate clients
getting set up needlessly.  This isn't a major problem, but it's
wasteful and different from what's intended.

This patch fixes that by using the control mutex to protect
both the lookup and (if needed) creation of the client.  It
was previously used just when creating.

This resolves:
    http://tracker.ceph.com/issues/3094

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
libceph: print more info for short message header

If an osd client response message arrives that has a front section
that's too big for the buffer set aside to receive it, a warning
gets reported and a new buffer is allocated.

The warning says nothing about which connection had the problem.
Add the peer type and number to what gets reported, to be a bit more
informative.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
rbd: set removing flag while holding list lock

When unmapping a device, its id is supplied, and that is used to
look up which rbd device should be unmapped.  Looking up the
device involves searching the rbd device list while holding
a spinlock that protects access to that list.

Currently all of this is done under protection of the control lock,
but that protection is going away soon.  To ensure the rbd_dev is
still valid (still on the list) while setting its REMOVING flag, do
so while still holding the list lock.  To do so, get rid of
__rbd_get_dev(), and open code what it did in the one place it
was used.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
rbd: protect against concurrent unmaps

Make sure two concurrent unmap operations on the same rbd device
won't collide, by only proceeding with the removal and cleanup of a
device if is not already underway.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
rbd: don't hold ctl_mutex to get/put device

When an rbd device is first getting mapped, its device registration
is protected the control mutex.  There is no need to do that though,
because the device has already been assigned an id that's guaranteed
to be unique.

An unmap of an rbd device won't proceed if the device has a non-zero
open count or is already being unmapped.  So there's no need to hold
the control mutex in that case either.

Finally, an rbd device can't be opened if it is being removed, and
it won't go away if there is a non-zero open count.  So here too
there's no need to hold the control mutex while getting or putting a
reference to an rbd device's Linux device structure.

Drop the mutex calls in these cases.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
rbd: use rwsem to protect header updates

Updating an image header needs to be protected to ensure it's
done consistently.  However distinct headers can be updated
concurrently without a problem.  Instead of using the global
control lock to serialize headder updates, just rely on the header
semaphore.  (It's already used, this just moves it out to cover
a broader section of the code.)

That leaves the control mutex protecting only the creation of rbd
clients, so rename it.

This resolves:
    http://tracker.ceph.com/issues/5222

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
rbd: take a little credit

Add a name to the list of authors.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
libceph: fix safe completion

handle_reply() calls complete_request() only if the first OSD reply
has ONDISK flag.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
libceph: fix truncate size calculation

check the "not truncated yet" case

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
ceph: fix cap release race

ceph_encode_inode_release() can race with ceph_open() and release
caps wanted by open files. So it should call __ceph_caps_wanted()
to get the wanted caps.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>