Pull ceph updates from Sage Weil:
 "The bulk of this pull is a series from Alex that refactors and cleans
  up the RBD code to lay the groundwork for supporting the new image
  format and evolving feature set.  There are also some cleanups in
  libceph, and for ceph there's fixed validation of file striping
  layouts and a bugfix in the code handling a shrinking MDS cluster."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (71 commits)
  ceph: avoid 32-bit page index overflow
  ceph: return EIO on invalid layout on GET_DATALOC ioctl
  rbd: BUG on invalid layout
  ceph: propagate layout error on osd request creation
  libceph: check for invalid mapping
  ceph: convert to use le32_add_cpu()
  ceph: Fix oops when handling mdsmap that decreases max_mds
  rbd: update remaining header fields for v2
  rbd: get snapshot name for a v2 image
  rbd: get the snapshot context for a v2 image
  rbd: get image features for a v2 image
  rbd: get the object prefix for a v2 rbd image
  rbd: add code to get the size of a v2 rbd image
  rbd: lay out header probe infrastructure
  rbd: encapsulate code that gets snapshot info
  rbd: add an rbd features field
  rbd: don't use index in __rbd_add_snap_dev()
  rbd: kill create_snap sysfs entry
  rbd: define rbd_dev_image_id()
  rbd: define some new format constants
  ...

There's no reason to call rcu_barrier() on every
deactivate_locked_super().  We only need to make sure that all delayed rcu
free inodes are flushed before we destroy related cache.

Removing rcu_barrier() from deactivate_locked_super() affects some fast
paths.  E.g.  on my machine exit_group() of a last process in IPC
namespace takes 0.07538s.  rcu_barrier() takes 0.05188s of that time.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

A recent change to /sbin/mountall causes any trailing '/' character
in the "device" (or fs_spec) field in /etc/fstab to be stripped.  As
a result, an entry for a ceph mount that intends to mount the root
of the name space ends up with now path portion, and the ceph mount
option processing code rejects this.

That is, an entry in /etc/fstab like:
    cephserver:port:/ /mnt ceph defaults 0 0
provides to the ceph code just "cephserver:port:" as the "device,"
and that gets rejected.

Although this is a bug in /sbin/mountall, we can have the ceph mount
code support an empty/nonexistent path, interpreting it to mean the
root of the name space.

RFC 5952 offers recommendations for how to express IPv6 addresses,
and recommends the usage found in RFC 3986 (which specifies the
format for URI's) for representing both IPv4 and IPv6 addresses that
include port numbers.  (See in particular the definition of
"authority" found in the Appendix of RFC 3986.)

According to those standards, no host specification will ever
contain a '/' character.  As a result, it is sufficient to scan a
provided "device" from an /etc/fstab entry for the first '/'
character, and if it's found, treat that as the beginning of the
path.  If no '/' character is present, we can treat the entire
string as the monitor host specification(s), and assume the path
to be the root of the name space.  We'll still require a ':' to
separate the host portion from the (possibly empty) path portion.

This means that we can more formally define how ceph will interpret
the "device" it's provided when processing a mount request:

    "device" will look like:
        <server_spec>[,<server_spec>...]:[<path>]
    where
        <server_spec> is <ip>[:<port>]
        <path> is optional, but if present must begin with '/'

This addresses http://tracker.newdream.net/issues/2919

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>

Pull Ceph changes from Sage Weil:
 "Lots of stuff this time around:

   - lots of cleanup and refactoring in the libceph messenger code, and
     many hard to hit races and bugs closed as a result.
   - lots of cleanup and refactoring in the rbd code from Alex Elder,
     mostly in preparation for the layering functionality that will be
     coming in 3.7.
   - some misc rbd cleanups from Josh Durgin that are finally going
     upstream
   - support for CRUSH tunables (used by newer clusters to improve the
     data placement)
   - some cleanup in our use of d_parent that Al brought up a while back
   - a random collection of fixes across the tree

  There is another patch coming that fixes up our ->atomic_open()
  behavior, but I'm going to hammer on it a bit more before sending it."

Fix up conflicts due to commits that were already committed earlier in
drivers/block/rbd.c, net/ceph/{messenger.c, osd_client.c}

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (132 commits)
  rbd: create rbd_refresh_helper()
  rbd: return obj version in __rbd_refresh_header()
  rbd: fixes in rbd_header_from_disk()
  rbd: always pass ops array to rbd_req_sync_op()
  rbd: pass null version pointer in add_snap()
  rbd: make rbd_create_rw_ops() return a pointer
  rbd: have __rbd_add_snap_dev() return a pointer
  libceph: recheck con state after allocating incoming message
  libceph: change ceph_con_in_msg_alloc convention to be less weird
  libceph: avoid dropping con mutex before fault
  libceph: verify state after retaking con lock after dispatch
  libceph: revoke mon_client messages on session restart
  libceph: fix handling of immediate socket connect failure
  ceph: update MAINTAINERS file
  libceph: be less chatty about stray replies
  libceph: clear all flags on con_close
  libceph: clean up con flags
  libceph: replace connection state bits with states
  libceph: drop unnecessary CLOSED check in socket state change callback
  libceph: close socket directly from ceph_con_close()
  ...

This is simply cleanup that will keep things more closely synced with the
userland code.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

Pass mount flags to sget() so that it can use them in initialising a new
superblock before the set function is called.  They could also be passed to the
compare function.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull Ceph updates for 3.4-rc1 from Sage Weil:
 "Alex has been busy.  There are a range of rbd and libceph cleanups,
  especially surrounding device setup and teardown, and a few critical
  fixes in that code.  There are more cleanups in the messenger code,
  virtual xattrs, a fix for CRC calculation/checks, and lots of other
  miscellaneous stuff.

  There's a patch from Amon Ott to make inos behave a bit better on
  32-bit boxes, some decode check fixes from Xi Wang, and network
  throttling fix from Jim Schutt, and a couple RBD fixes from Josh
  Durgin.

  No new functionality, just a lot of cleanup and bug fixing."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (65 commits)
  rbd: move snap_rwsem to the device, rename to header_rwsem
  ceph: fix three bugs, two in ceph_vxattrcb_file_layout()
  libceph: isolate kmap() call in write_partial_msg_pages()
  libceph: rename "page_shift" variable to something sensible
  libceph: get rid of zero_page_address
  libceph: only call kernel_sendpage() via helper
  libceph: use kernel_sendpage() for sending zeroes
  libceph: fix inverted crc option logic
  libceph: some simple changes
  libceph: small refactor in write_partial_kvec()
  libceph: do crc calculations outside loop
  libceph: separate CRC calculation from byte swapping
  libceph: use "do" in CRC-related Boolean variables
  ceph: ensure Boolean options support both senses
  libceph: a few small changes
  libceph: make ceph_tcp_connect() return int
  libceph: encapsulate some messenger cleanup code
  libceph: make ceph_msgr_wq private
  libceph: encapsulate connection kvec operations
  libceph: move prepare_write_banner()
  ...

Many ceph-related Boolean options offer the ability to both enable
and disable a feature.  For all those that don't offer this, add
a new option so that they do.

Note that ceph_show_options()--which reports mount options currently
in effect--only reports the option if it is different from the
default value.

Signed-off-by: Alex Elder <elder@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>

ceph_parse_options() takes the address of a pointer as an argument
and uses it to return the address of an allocated structure if
successful.  With this interface is not evident at call sites that
the pointer is always initialized.  Change the interface to return
the address instead (or a pointer-coded error code) to make the
validity of the returned pointer obvious.

Signed-off-by: Alex Elder <elder@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>

All names defined in the directory and file virtual extended
attribute tables are constant, and the size of each is known at
compile time.  So there's no need to compute their length every
time any file's attribute is listed.

Record the length of each string and use it when needed to determine
the space need to represent them.  In addition, compute the
aggregate size of strings in each table just once at initialization
time.

Signed-off-by: Alex Elder <elder@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>