LU-3581 osc: Lustre returns EINTR from writes when SA_RESTART is set

When Lustre is in a read or write system call and receives a
SIGALRM, it will return EINTR if interrupted in osc_enter_cache.
This prevents the system call from being restarted if
SA_RESTART is set in the handler.

This patch changes behavior in this location to return ERESTARTSYS
when a signal arrives during the call to l_wait_event.

Signed-off-by: Patrick Farrell <paf@cray.com>
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: I95423c5d572974352173f3c5c94d980385bfef29
Reviewed-on: http://review.whamcloud.com/7002
Reviewed-by: Rahul Deshmukh <rahul_deshmukh@xyratex.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Cory Spitz <spitzcor@cray.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>

diff --git a/lustre/osc/osc_cache.c b/lustre/osc/osc_cache.c
index bd7a674..8d9888f 100644 (file)
--- a/lustre/osc/osc_cache.c
+++ b/lustre/osc/osc_cache.c
@@ -1551,13 +1551,24 @@ static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
 
                /* l_wait_event is interrupted by signal, or timed out */
                if (rc < 0) {
 
                /* l_wait_event is interrupted by signal, or timed out */
                if (rc < 0) {

-                       if (rc == -ETIMEDOUT) {
+                       switch (rc) {
+                       case -ETIMEDOUT:

                                OSC_DUMP_GRANT(D_ERROR, cli,
                                                "try to reserve %d.\n", bytes);
                                osc_extent_tree_dump(D_ERROR, osc);
                                rc = -EDQUOT;
                                OSC_DUMP_GRANT(D_ERROR, cli,
                                                "try to reserve %d.\n", bytes);
                                osc_extent_tree_dump(D_ERROR, osc);
                                rc = -EDQUOT;

+                               break;
+                       case -EINTR:
+                               /* Ensures restartability - LU-3581 */
+                               rc = -ERESTARTSYS;
+                               break;
+                       default:
+                               CDEBUG(D_CACHE, "%s: event for cache space @"
+                                      " %p never arrived due to %d\n",
+                                      cli->cl_import->imp_obd->obd_name,
+                                      &ocw, rc);
+                               break;

                        }
                        }

-

                        cfs_list_del_init(&ocw.ocw_entry);
                        GOTO(out, rc);
                }
                        cfs_list_del_init(&ocw.ocw_entry);
                        GOTO(out, rc);
                }