An error occurring on a ceph connection is treated as a fault,
causing the connection to be reset.  The initial part of this fault
handling has to be done while holding the connection mutex, but
it must then be dropped for the last part.

Separate the part of this fault handling that executes without the
lock into its own function, con_fault_finish().  Move the call to
this new function, as well as call that drops the connection mutex,
into ceph_fault().  Rename that function con_fault() to reflect that
it's only handling the connection part of the fault handling.

The motivation for this was a warning from sparse about the locking
being done here.  Rearranging things this way keeps all the mutex
manipulation within ceph_fault(), and this stops sparse from
complaining.

This partially resolves:
    http://tracker.ceph.com/issues/4184Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Collect the code that tests for and implements a backoff delay for a
ceph connection into a new function, ceph_backoff().

Make the debug output messages in that part of the code report
things consistently by reporting a message in the socket closed
case, and by making the one for PREOPEN state report the connection
pointer like the rest.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Eliminate most of the problems in the libceph code that cause sparse
to issue warnings.
    - Convert functions that are never referenced externally to have
      static scope.
    - Pass NULL rather than 0 for a pointer argument in one spot in
      ceph_monc_delete_snapid()

This partially resolves:
    http://tracker.ceph.com/issues/4184Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Fix the causes for sparse warnings reported in the ceph file system
code.  Here there are only two (and they're sort of silly but
they're easy to fix).

This partially resolves:
    http://tracker.ceph.com/issues/4184Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Fengguang Wu reminded me that there were outstanding sparse reports
in the ceph and rbd code.  This patch fixes these problems in rbd
that lead to those reports:
    - Convert functions that are never referenced externally to have
      static scope.
    - Add a lockdep annotation to rbd_request_fn(), because it
      releases a lock before acquiring it again.

This partially resolves:
    http://tracker.ceph.com/issues/4184Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Define and use functions that encapsulate operations performed on
a connection's flags.

This resolves:
    http://tracker.ceph.com/issues/4234Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Add dout() calls to facilitate tracing of image and object requests.
Change a few existing calls so they use __func__ rather than the
hard-coded function name.  Have calls always add ":" after the name
of the function, and prefix pointer values with a consistent tag
indicating what it represents.  (Note that there remain some older
dout() calls that are left untouched by this patch.)

Issue a warning if rbd_osd_write_callback() ever gets a short write.

This resolves:
    http://tracker.ceph.com/issues/4235Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Let's go shopping!

I'm afraid this may not have gotten it right:
    07741308  rbd: add barriers near done flag operations

The smp_wmb() should have been done *before* setting the done flag,
to ensure all other data was valid before marking the object request
done.

Switch to use atomic_inc_return() here to set the done flag, which
allows us to verify we don't mark something done more than once.
Doing this also implies general barriers before and after the call.

And although a read memory barrier might have been sufficient before
reading the done flag, convert this to a full memory barrier just
to put this issue to bed.

This resolves:
    http://tracker.ceph.com/issues/4238Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

The old request code simply ignored zero-length requests.  We should
still operate that same way to avoid any changes in behavior.  We
can implement handling for special zero-length requests separately
(see http://tracker.ceph.com/issues/4236).

Add some assertions based on this new constraint.

This resolves:
    http://tracker.ceph.com/issues/4237Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Different versions of glibc are broken in different ways, but the short of
it is that for the time being, frsize should == bsize, and be used as the
multiple for the blocks, free, and available fields.  This mirrors what is
done for NFS.  The previous reporting of the page size for frsize meant
that newer glibc and df would report a very small value for the fs size.

Fixes http://tracker.ceph.com/issues/3793.
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>

The return values provided for ceph_copy_to_page_vector() and
ceph_copy_from_page_vector() serve no purpose, so get rid of them.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

The result of ceph_copy_from_page_vector() is simply the length
argument it is provided.

This is called by rbd_obj_method_sync(), which returns the result if
it's non-negative.  But we always either ignore or overwrite that
return value.  So explicitly ignore what's returned by the copy
function, and have rbd_obj_method_sync() always return either a
negative errno or 0.

We also return the result of ceph_copy_from_page_vector() in
rbd_obj_read_sync().  There we still want to return the number of
bytes transferred, but we can use the value we already have in hand
rather than what ceph_copy_from_page_vector() provides.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

In rbd_obj_read_sync(), verify the number of bytes transferred won't
exceed what can be represented by a size_t before using it to
indicate the number of bytes to copy to the result buffer.

(The real motivation for this is to prepare for the next patch.)
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

The functions used for working with ceph page vectors are defined
with char pointers, but they're really intended to operate on
untyped data.  Change the types of these function parameters
to (void *) to reflect this.

(Note that the functions now assume void pointer arithmetic works
like arithmetic on char pointers.)
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

There are three ceph page vector functions declared in
"fs/ceph/super.h" that don't belong there.  They're
probably left over from some long-ago code reorganization.

They're properly declared in "include/linux/ceph/libceph.h"
so just delete the ones in "super.h".

This and the next few commits resolve:
    http://tracker.ceph.com/issues/4053Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Add support for CEPH_OSD_OP_STAT operations in the osd client
and in rbd.

This operation sends no data to the osd; everything required is
encoded in identity of the target object.

The result will be ENOENT if the object doesn't exist.  If it does
exist and no other error occurs the server returns the size and last
modification time of the target object as output data (in little
endian format).  The size is a 64 bit unsigned and the time is
ceph_timespec structure (two unsigned 32-bit integers, representing
a seconds and nanoseconds value).

This resolves:
    http://tracker.ceph.com/issues/4007Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

The for_each_obj_request*() macros should parenthesize their uses of
the ireq parameter.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Simplify the way the data length recorded in a message header is
calculated in ceph_osdc_build_request().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Pull input subsystem fixes from Dmitry Torokhov:
 "Two small driver fixups and a documentation update for managed input
  devices"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: wacom - fix wacom_set_report retry logic
  Input: document that unregistering managed devices is not necessary
  Input: lm8323 - fix checking PWM interrupt status

Update ceph_mds_state_name() and ceph_mds_op_name() to include the
newly-added definitions in "ceph_fs.h", and to match its counterpart
in the user space code.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Update most of "include/linux/ceph/ceph_fs.h" to match its user
space counterpart in "src/include/ceph_fs.h" in the ceph tree.

Everything that has changed is either:
    - added definitions (therefore no real effect on existing code)
    - deleting unused symbols
    - added or revised comments

There were some differences between the struct definitions for
ceph_mon_subscribe_item and the open field of ceph_mds_request_args;
those differences remain.

This and the next commit resolve:
    http://tracker.ceph.com/issues/4165Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

In osd_req_encode_op() there are a few cases that handle osd
opcodes that are never used in the kernel.  The presence of
this code gives the impression it's correct (which really can't
be assumed), and may impose some unnecessary restrictions on
some upcoming refactoring of this code.

So delete this effectively dead code, and report uses of the
previously handled cases as unsupported.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

If osd_req_encode_op() is given any opcode it doesn't recognize
it reports an error.

This patch fleshes out that routine to distinguish between
well-defined but unsupported values and values that are simply
bogus.

This and the next commit are related to:
    http://tracker.ceph.com/issues/4126Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Update ceph_osd_op_name() to include the newly-added definitions in
"rados.h", and to match its counterpart in the user space code.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Add the definition of ceph_osd_state_name(), to match its
counterpart in user space.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Update most of "include/linux/ceph/rados.h" to match its user space
counterpart in "src/include/rados.h" in the ceph tree.

Almost everything that has changed is either:
    - added or revised comments
    - added definitions (therefore no real effect on existing code)
    - defining the same value a different way (e.g., "1 << 0" vs "1")

The only exceptions are:
    - The declaration of ceph_osd_state_name() was excluded; that
      will be inserted in the next patch.
    - ceph_osd_op_mode_read() and ceph_osd_op_mode_modify() are
      defined differently, but they were never used in the kernel
    - CEPH_OSD_FLAG_PEERSTAT is now CEPH_OSD_FLAG_PEERSTAT_OLD, but
      that was never used in the kernel

Anything that was present in this file but not in its user space
counterpart was left intact here.  I left the definitions of
EOLDSNAPC and EBLACKLISTED using numerical values here; I'm
not sure the right way to go with those.

This and the next two commits resolve:
    http://tracker.ceph.com/issues/4164Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

There are no actual users of ceph_osdc_wait_event().  This would
have been one-shot events, but we no longer support those so just
get rid of this function.

Since this leaves nothing else that waits for the completion of an
event, we can get rid of the completion in a struct ceph_osd_event.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

There is only one caller of ceph_osdc_create_event(), and it
provides 0 as its "one_shot" argument.  Get rid of that argument and
just use 0 in its place.

Replace the code in handle_watch_notify() that executes if one_shot
is nonzero in the event with a BUG_ON() call.

While modifying "osd_client.c", give handle_watch_notify() static
scope.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

There is no caller of ceph_calc_raw_layout() outside of libceph, so
there's no need to export from the module.

Furthermore, there is only one caller, in calc_layout(), and it
is not much more than a simple wrapper for that function.

So get rid of ceph_calc_raw_layout() and embed it instead within
calc_layout().

While touching "osd_client.c", get rid of the unnecessary forward
declaration of __send_request().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

The only callers of ceph_osdc_init() and ceph_osdc_stop()
ceph_create_client() and ceph_destroy_client() (respectively)
and they are in the same kernel module as those two functions.
There's therefore no need to export those interfaces, so don't.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Two of the three callers of the osd client's send_queued() function
already hold the osd client mutex and drop it before the call.

Change send_queued() so it assumes the caller holds the mutex, and
update all callers accordingly.  Rename it __send_queued() to match
the convention used elsewhere in the file with respect to the lock.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

The "num_reply" parameter to ceph_osdc_new_request() is never
used inside that function, so get rid of it.

Note that ceph_sync_write() passes 2 for that argument, while all
other callers pass 1.  It doesn't matter, but perhaps someone should
verify this doesn't indicate a problem.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

There is only one caller of ceph_osdc_writepages(), and it always
passes 0 as its "flags" argument.  Get rid of that argument and
replace its use in ceph_osdc_writepages() with 0.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

There is only one caller of ceph_osdc_writepages(), and it always
passes 0 as its "dosync" argument.  Get rid of that argument and
replace its use in ceph_osdc_writepages() with 0.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

There is only one caller of ceph_osdc_writepages(), and it always
passes the value true as its "nofail" argument.  Get rid of that
argument and replace its use in ceph_osdc_writepages() with the
constant value true.

This and a number of cleanup patches that follow resolve:
    http://tracker.ceph.com/issues/4126Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

The layout of struct ceph_osd_req_op leaves lots of holes.
Rearranging things a little for better field alignment
reduces the size by a third.

This resolves:
    http://tracker.ceph.com/issues/4163Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Commit c060f943 ("mm: use aligned zone start for pfn_to_bitidx
calculation") fixed out calculation of the index into the pageblock
bitmap when a !SPARSEMEM zome was not aligned to pageblock_nr_pages.

However, the _allocation_ of that bitmap had never taken this alignment
requirement into accout, so depending on the exact size and alignment of
the zone, the use of that index could then access past the allocation,
resulting in some very subtle memory corruption.

This was reported (and bisected) by Ingo Molnar: one of his random
config builds would hang with certain very specific kernel command line
options.

In the meantime, commit c060f943 has been marked for stable, so this
fix needs to be back-ported to the stable kernels that backported the
commit to use the right alignment.
Bisected-and-tested-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'stable/for-linus-3.8-rc7-tag-two' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull xen fixes from Konrad Rzeszutek Wilk:
 "Two fixes:

   - A simple bug-fix for redundant NULL check.

   - CVE-2013-0228/XSA-42: x86/xen: don't assume %ds is usable in
     xen_iret for 32-bit PVOPS

  and two reverts:

   - Revert the PVonHVM kexec.  The patch introduces a regression with
     older hypervisor stacks, such as Xen 4.1."

* tag 'stable/for-linus-3.8-rc7-tag-two' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  Revert "xen PVonHVM: use E820_Reserved area for shared_info"
  Revert "xen/PVonHVM: fix compile warning in init_hvm_pv_info"
  xen: remove redundant NULL check before unregister_and_remove_pcpu().
  x86/xen: don't assume %ds is usable in xen_iret for 32-bit PVOPS.