Pull ceph bug-fixes from Sage Weil:
 "These include a couple fixes to the new fscache code that went in
  during the last cycle (which will need to go stable@ shortly as well),
  a couple client-side directory fragmentation fixes, a fix for a race
  in the cap release queuing path, and a couple race fixes in the
  request abort and resend code.

  Obviously some of this could have gone into 3.12 final, but I
  preferred to overtest rather than send things in for a late -rc, and
  then my travel schedule intervened"

* 'for-linus-bugs' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: allocate non-zero page to fscache in readpage()
  ceph: wake up 'safe' waiters when unregistering request
  ceph: cleanup aborted requests when re-sending requests.
  ceph: handle race between cap reconnect and cap release
  ceph: set caps count after composing cap reconnect message
  ceph: queue cap release in __ceph_remove_cap()
  ceph: handle frag mismatch between readdir request and reply
  ceph: remove outdated frag information
  ceph: hung on ceph fscache invalidate in some cases

ceph_osdc_readpages() returns number of bytes read, currently,
the code only allocate full-zero page into fscache, this patch
fixes this.

Signed-off-by: Li Wang <liwang@ubuntukylin.com>
Reviewed-by: Milosz Tanski <milosz@adfin.com>
Reviewed-by: Sage Weil <sage@inktank.com>

We also need to wake up 'safe' waiters if error occurs or request
aborted. Otherwise sync(2)/fsync(2) may hang forever.

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

Aborted requests usually get cleared when the reply is received.
If MDS crashes, no reply will be received. So we need to cleanup
aborted requests when re-sending requests.

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

When a cap get released while composing the cap reconnect message.
We should skip queuing the release message if the cap hasn't been
added to the cap reconnect message.

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

It's possible that some caps get released while composing the cap
reconnect message.

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

call __queue_cap_release() in __ceph_remove_cap(), this avoids
acquiring s_cap_lock twice.

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

If client has outdated directory fragments information, it may request
readdir an non-existent directory fragment. In this case, the MDS finds
an approximate directory fragment and sends its contents back to the
client. When receiving a reply with fragment that is different than the
requested one, the client need to reset the 'readdir offset'.

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

If directory fragments change, fill_inode() inserts new frags into
the fragtree, but it does not remove outdated frags from the fragtree.
This patch fixes it.

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

Provide the ability to enable and disable fscache cookies.  A disabled cookie
will reject or ignore further requests to:

	Acquire a child cookie
	Invalidate and update backing objects
	Check the consistency of a backing object
	Allocate storage for backing page
	Read backing pages
	Write to backing pages

but still allows:

	Checks/waits on the completion of already in-progress objects
	Uncaching of pages
	Relinquishment of cookies

Two new operations are provided:

 (1) Disable a cookie:

	void fscache_disable_cookie(struct fscache_cookie *cookie,
				    bool invalidate);

     If the cookie is not already disabled, this locks the cookie against other
     dis/enablement ops, marks the cookie as being disabled, discards or
     invalidates any backing objects and waits for cessation of activity on any
     associated object.

     This is a wrapper around a chunk split out of fscache_relinquish_cookie(),
     but it reinitialises the cookie such that it can be reenabled.

     All possible failures are handled internally.  The caller should consider
     calling fscache_uncache_all_inode_pages() afterwards to make sure all page
     markings are cleared up.

 (2) Enable a cookie:

	void fscache_enable_cookie(struct fscache_cookie *cookie,
				   bool (*can_enable)(void *data),
				   void *data)

     If the cookie is not already enabled, this locks the cookie against other
     dis/enablement ops, invokes can_enable() and, if the cookie is not an
     index cookie, will begin the procedure of acquiring backing objects.

     The optional can_enable() function is passed the data argument and returns
     a ruling as to whether or not enablement should actually be permitted to
     begin.

     All possible failures are handled internally.  The cookie will only be
     marked as enabled if provisional backing objects are allocated.

A later patch will introduce these to NFS.  Cookie enablement during nfs_open()
is then contingent on i_writecount <= 0.  can_enable() checks for a race
between open(O_RDONLY) and open(O_WRONLY/O_RDWR).  This simplifies NFS's cookie
handling and allows us to get rid of open(O_RDONLY) accidentally introducing
caching to an inode that's open for writing already.

One operation has its API modified:

 (3) Acquire a cookie.

	struct fscache_cookie *fscache_acquire_cookie(
		struct fscache_cookie *parent,
		const struct fscache_cookie_def *def,
		void *netfs_data,
		bool enable);

     This now has an additional argument that indicates whether the requested
     cookie should be enabled by default.  It doesn't need the can_enable()
     function because the caller must prevent multiple calls for the same netfs
     object and it doesn't need to take the enablement lock because no one else
     can get at the cookie before this returns.

Signed-off-by: David Howells <dhowells@redhat.com