LU-9785 lov: take lov layout lock for I/O with ignore_layout

A rule of thumb for taking lov layout configuration lock is if I/O
is initiated from LLITE layer, it should grab the lock. If an I/O
starts from the OSC layer, it won't be necessary because if the OSC
object exists, layout reconfiguration will move forward.

Right now CIT_MISC + ci_ignore_layout can identify the I/O from the
OSC layer, I just use this in lov_io_init() for this purpose. In the
future, an explicit bit may be defined for this.

Lustre-commit: e43b0e5c0ccbacd8adf30713babd865b5a7c58c7
Lustre-change: https://review.whamcloud.com/29638

Signed-off-by: Jinshan Xiong <jinshan.xiong@gmail.com>
Change-Id: I2fe37a957b5fb4161c4c723062f6469b915c1dd5
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-on: https://review.whamcloud.com/33965
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/lov/lov_object.c b/lustre/lov/lov_object.c
index e26769c..bae68bb 100644 (file)
--- a/lustre/lov/lov_object.c
+++ b/lustre/lov/lov_object.c
@@ -1062,8 +1062,13 @@ int lov_io_init(const struct lu_env *env, struct cl_object *obj,
               PFID(lu_object_fid(&obj->co_lu)), io, io->ci_type,
               io->ci_ignore_layout, io->ci_verify_layout);
 
+       /* IO type CIT_MISC with ci_ignore_layout set are usually invoked from
+        * the OSC layer. It shouldn't take lov layout conf lock in that case,
+        * because as long as the OSC object exists, the layout can't be
+        * reconfigured. */
        return LOV_2DISPATCH_MAYLOCK(cl2lov(obj), llo_io_init,
-                                    !io->ci_ignore_layout, env, obj, io);
+                       !(io->ci_ignore_layout && io->ci_type == CIT_MISC),
+                       env, obj, io);
 }
 
 /**