kernel_optimize_test/net/ceph
Alex Elder 26be88087a libceph: change how "safe" callback is used
An osd request currently has two callbacks.  They inform the
initiator of the request when we've received confirmation for the
target osd that a request was received, and when the osd indicates
all changes described by the request are durable.

The only time the second callback is used is in the ceph file system
for a synchronous write.  There's a race that makes some handling of
this case unsafe.  This patch addresses this problem.  The error
handling for this callback is also kind of gross, and this patch
changes that as well.

In ceph_sync_write(), if a safe callback is requested we want to add
the request on the ceph inode's unsafe items list.  Because items on
this list must have their tid set (by ceph_osd_start_request()), the
request added *after* the call to that function returns.  The
problem with this is that there's a race between starting the
request and adding it to the unsafe items list; the request may
already be complete before ceph_sync_write() even begins to put it
on the list.

To address this, we change the way the "safe" callback is used.
Rather than just calling it when the request is "safe", we use it to
notify the initiator the bounds (start and end) of the period during
which the request is *unsafe*.  So the initiator gets notified just
before the request gets sent to the osd (when it is "unsafe"), and
again when it's known the results are durable (it's no longer
unsafe).  The first call will get made in __send_request(), just
before the request message gets sent to the messenger for the first
time.  That function is only called by __send_queued(), which is
always called with the osd client's request mutex held.

We then have this callback function insert the request on the ceph
inode's unsafe list when we're told the request is unsafe.  This
will avoid the race because this call will be made under protection
of the osd client's request mutex.  It also nicely groups the setup
and cleanup of the state associated with managing unsafe requests.

The name of the "safe" callback field is changed to "unsafe" to
better reflect its new purpose.  It has a Boolean "unsafe" parameter
to indicate whether the request is becoming unsafe or is now safe.
Because the "msg" parameter wasn't used, we drop that.

This resolves the original problem reportedin:
    http://tracker.ceph.com/issues/4706

Reported-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
2013-05-01 21:18:52 -07:00
..
crush crush: avoid recursion if we have already collided 2013-01-17 12:42:39 -06:00
armor.c libceph: Fix base64-decoding when input ends in newline. 2011-03-15 09:14:02 -07:00
auth_none.c ceph: messenger: reduce args to create_authorizer 2012-05-17 08:18:12 -05:00
auth_none.h
auth_x_protocol.h
auth_x.c libceph: wrap auth ops in wrapper functions 2013-05-01 21:17:14 -07:00
auth_x.h libceph: add update_authorizer auth method 2013-05-01 21:17:13 -07:00
auth.c libceph: wrap auth methods in a mutex 2013-05-01 21:17:15 -07:00
buffer.c net: allow GFP_HIGHMEM in __vmalloc() 2010-11-21 10:04:04 -08:00
ceph_common.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2013-02-28 17:43:09 -08:00
ceph_fs.c ceph: fix file mode calculation 2011-07-19 11:25:04 -07:00
ceph_hash.c net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
ceph_strings.c libceph: update ceph_osd_op_name() 2013-02-18 12:20:18 -06:00
crypto.c libceph: eliminate sparse warnings 2013-02-25 15:37:18 -06:00
crypto.h libceph: fix crypto key null deref, memory leak 2012-08-02 09:19:20 -07:00
debugfs.c libceph: keep source rather than message osd op array 2013-05-01 21:18:12 -07:00
Kconfig net/ceph: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:39:33 -08:00
Makefile Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-12-08 13:47:38 -08:00
messenger.c libceph: add, don't set data for a message 2013-05-01 21:18:34 -07:00
mon_client.c libceph: wrap auth ops in wrapper functions 2013-05-01 21:17:14 -07:00
msgpool.c libceph: initialize msgpool message types 2012-07-30 09:29:50 -07:00
osd_client.c libceph: change how "safe" callback is used 2013-05-01 21:18:52 -07:00
osdmap.c libceph: define ceph_decode_pgid() only once 2013-05-01 21:17:52 -07:00
pagelist.c ceph: use list_move_tail instead of list_del/list_add_tail 2012-10-01 14:30:49 -05:00
pagevec.c libceph: drop return value from page vector copy routines 2013-02-19 19:14:05 -06:00