It's not obvious whether the snapshot pointer whose address is
provided to __rbd_add_snap_dev() will be assigned by that function.
Change it to return the snapshot, or a pointer-coded errno in the
event of a failure.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com> 

rbd_req_sync_unwatch() only ever uses rbd_dev->header_name as the
value of its "object_name" parameter, and that value is available
within the function already.  So get rid of the parameter.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

rbd_req_sync_notify_ack() only ever uses rbd_dev->header_name as the
value of its "object_name" parameter, and that value is available
within the function already.  So get rid of the parameter.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

rbd_req_sync_notify() only ever uses rbd_dev->header_name as the
value of its "object_name" parameter, and that value is available
within the function already.  So get rid of the parameter.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

rbd_req_sync_watch() is only called in one place, and in that place
it passes rbd_dev->header_name as the value of the "object_name"
parameter.  This value is available within the function already.

Having the extra parameter leaves the impression the object name
could take on different values, but it does not.

So get rid of the parameter.  We can always add it back again if
we find we want to watch some other object in the future.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Both rbd_register_snap_dev() and __rbd_remove_snap_dev() have
rbd_dev parameters that are unused.  Remove them.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

The function rbd_header_from_disk() is only called in one spot, and
it passes GFP_KERNEL as its value for the gfp_flags parameter.

Just drop that parameter and substitute GFP_KERNEL everywhere within
that function it had been used.  (If we find we need the parameter
again in the future it's easy enough to add back again.)
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

The "snapc" parameter to in rbd_req_sync_read() is not used, so
get rid of it.
Reported-by: NJosh Durgin <josh.durgin@inktank.com>
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

The "id" field of an rbd device structure represents the unique
client-local device id mapped to the underlying rbd image.  Each rbd
image will have another id--the image id--and each snapshot has its
own id as well.  The simple name "id" no longer conveys the
information one might like to have.

Rename the device "id" field in struct rbd_dev to be "dev_id" to
make it a little more obvious what we're dealing with without having
to think more about context.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

If an rbd image header is read and it doesn't begin with the
expected magic information, a warning is displayed.  This is
a fairly simple test, but it could be extended at some point.
Fix the comparison so it actually looks at the "text" field
rather than the front of the structure.

In any case, encapsulate the validity test in its own function.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

There was a dout() call in rbd_do_request() that was reporting
the reporting the offset as the length and vice versa.  While
fixing that I did a quick scan of other dout() calls and fixed
a couple of other minor things.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

This just replaces a while loop with list_for_each_entry_safe()
in __rbd_remove_all_snaps().
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

In commit c666601a there was inadvertently added an extra
initialization of rbd_dev->header_rwsem.  This gets rid of the
duplicate.
Reported-by: NGuangliang Zhao <gzhao@suse.com>
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

The snap_seq field in an rbd_image_header structure held the value
from the rbd image header when it was last refreshed.  We now
maintain this value in the snapc->seq field.  So get rid of the
other one.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

In rbd_header_add_snap() there is code to set snapc->seq to the
just-added snapshot id.  This is the only remnant left of the
use of that field for recording which snapshot an rbd_dev was
associated with.  That functionality is no longer supported,
so get rid of that final bit of code.

Doing so means we never actually set snapc->seq any more.  On the
server, the snapshot context's sequence value represents the highest
snapshot id ever issued for a particular rbd image.  So we'll make
it have that meaning here as well.  To do so, set this value
whenever the rbd header is (re-)read.  That way it will always be
consistent with the rest of the snapshot context we maintain.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

In rbd_header_set_snap(), there is logic to make the snap context's
seq field get set to a particular snapshot id, or 0 if there is no
snapshot for the rbd image.

This seems to be an artifact of how the current snapshot id for an
rbd_dev was recorded before the rbd_dev->snap_id field began to be
used for that purpose.

There's no need to update the value of snapc->seq here any more, so
stop doing it.  Tidy up a few local variables in that function
while we're at it.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

In what appears to be an artifact of a different way of encoding
whether an rbd image maps a snapshot, __rbd_refresh_header() has
code that arranges to update the seq value in an rbd image's
snapshot context to point to the first entry in its snapshot
array if that's where it was pointing initially.

We now use rbd_dev->snap_id to record the snapshot id--using the
special value CEPH_NOSNAP to indicate the rbd_dev is not mapping a
snapshot at all.

There is therefore no need to check for this case, nor to update the
seq value, in __rbd_refresh_header().  Just preserve the seq value
that rbd_read_header() provides (which, at the moment, is nothing).
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Previously the original header version was sent. Now, we update it
when the header changes.
Signed-off-by: NJosh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: NAlex Elder <elder@inktank.com>

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: NJosh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: NAlex Elder <elder@inktank.com>

The image may have been resized.
Signed-off-by: NJosh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: NAlex Elder <elder@inktank.com>

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: NJosh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: NAlex Elder <elder@inktank.com>

Snapshots cannot be resized, and the new capacity of head should not
be reflected by the snapshot.
Signed-off-by: NJosh Durgin <josh.durgin@inktank.com>
Reviewed-by: NAlex Elder <elder@inktank.com>

When a snapshot is deleted, the OSD will return ENOENT when reading
from it. This is normally interpreted as a hole by rbd, which will
return zeroes. To minimize the time in which this can happen, stop
requests early when we are notified that our snapshot no longer
exists.

[elder@inktank.com: updated __rbd_init_snaps_header() logic]
Signed-off-by: NJosh Durgin <josh.durgin@inktank.com>
Reviewed-by: NAlex Elder <elder@inktank.com>

Several functions include a num_reply parameter, but it is never
used.  Just get rid of it everywhere--it seems to be something
that never got fully implemented.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Use the name "ceph_opts" consistently (rather than just "opt") for
pointers to a ceph_options structure.

Change the few spots that don't use "rbd_opts" for a rbd_options
pointer to match the rest.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Rename variables named "obj" which represent object names so they're
consistently named "object_name".

Rename the "cls" and "method" parameters in rbd_req_sync_exec()
to be "class_name" and "method_name", and make similar changes
to the names of local variables in that function representing
the lengths of those names.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

An rbd image is not a single object, but a logical construct made up
of an aggregation of objects.

Rename some fields in struct rbd_dev, in hopes of reinforcing this.
    obj         --> image_name
    obj_len     --> image_name_len
    obj_md_name --> header_name
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Most variables that represent a struct rbd_device are named
"rbd_dev", but in some cases "dev" is used instead.  Change all the
"dev" references so they use "rbd_dev" consistently, to make it
clear from the name that we're working with an RBD device (as
opposed to, for example, a struct device).  Similarly, change the
name of the "dev" field in struct rbd_notify_info to be "rbd_dev".
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

There is no need to impose a small limit the length of the snapshot
name recorded for an rbd image in a struct rbd_dev.  Remove the
limitation by allocating space for the snapshot name dynamically.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

There is no need to impose a small limit the length of the rbd image
name recorded in a struct rbd_dev.  Remove the limitation by
allocating space for the image name dynamically.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

There is no need to impose a small limit the length of the header
name recorded for an rbd image in a struct rbd_dev.  Remove the
limitation by allocating space for the header name dynamically.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

There is no need to impose a small limit the length of the object
prefix recorded for an rbd image in a struct rbd_image_header.
Remove the limitation by allocating space for the object prefix
dynamically.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

There is no need to impose a small limit the length of the pool name
recorded for an rbd image in a struct rbd_device.  Remove the
limitation by allocating space for the pool name ynamically.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Add an entry under /sys/bus/rbd/devices/<N>/ named "pool_id" that
provides the id for the pool the rbd image is assocatied with.  This
is in addition to the pool name already provided.

Rename the "poolid" field in struct rbd_device  to be "pool_id".

Update the documentation to reflect the addition of this new entry.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Each rbd image has a name that forms the basis of all data objects
backing the device.  Old (format 1) images refer to this name as the
"block name," while new (format 2) images use the term "object
prefix" for this.

Change the field name in the in-core rbd image header structure to
reflect the more modern usage.  We intentionally keep the the name
"block_name" in the on-disk definition for format 1 image headers.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NYehuda Sadeh <yehuda@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Define a new function dup_token(), to be used during argument
parsing for making dynamically-allocated copies of tokens being
parsed.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NYehuda Sadeh <yehuda@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

In rbd_req_sync_notify_ack(), a local variable was needlessly being
used to hold a null pointer.  Just pass NULL instead.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NYehuda Sadeh <yehuda@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Sparse complains about this because:
drivers/block/rbd.c:996:20: warning: cast to restricted __le32
drivers/block/rbd.c:996:20: warning: cast from restricted __le16

These are set in osd_req_encode_op() and they are le16.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NAlex Elder <elder@inktank.com>

ceph_snap_context->snaps is an u64 array
Signed-off-by: NZheng Yan <zheng.z.yan@intel.com>
Reviewed-by: NAlex Elder <elder@inktank.com>

This function rereads the entire header and handles any changes in
it, not just changes in snapshots.
Signed-off-by: NJosh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: NAlex Elder <elder@dreamhost.com>
Reviewed-by: NYehuda Sadeh <yehuda@hq.newdream.net>