LU-3027 lov: to not modify lov lock when sublock is canceled

Otherwise it will cause wrong lock to be enqueued.

lls_ever_canceled is introduced to solve potential performance
problem by this patch.

Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Change-Id: I1ea62902c9d1a468f5952f30a8dc5dec22b8bb1c
Reviewed-on: http://review.whamcloud.com/7841
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>

diff --git a/lustre/lov/lov_cl_internal.h b/lustre/lov/lov_cl_internal.h
index 2e899ac..a34bdcf 100644 (file)
--- a/lustre/lov/lov_cl_internal.h
+++ b/lustre/lov/lov_cl_internal.h
@@ -320,7 +320,8 @@ struct lov_lock {
          * Set when sub-lock was canceled, while top-lock was being
          * used, or unused.
          */
-       unsigned int           lls_cancel_race:1;
+       unsigned int           lls_cancel_race:1,
+                               lls_ever_canceled:1;
         /**
          * An array of sub-locks
          *

diff --git a/lustre/lov/lov_lock.c b/lustre/lov/lov_lock.c
index 794354d..547bdca 100644 (file)
--- a/lustre/lov/lov_lock.c
+++ b/lustre/lov/lov_lock.c
@@ -1023,6 +1023,9 @@ static int lov_lock_fits_into(const struct lu_env *env,
        if (need->cld_enq_flags != lov->lls_orig.cld_enq_flags)
                return 0;
 
+       if (lov->lls_ever_canceled)
+               return 0;
+
         if (need->cld_mode == CLM_GROUP)
                 /*
                  * always allow to match group lock.

diff --git a/lustre/lov/lovsub_lock.c b/lustre/lov/lovsub_lock.c
index 3dcc6c2..22f35e6 100644 (file)
--- a/lustre/lov/lovsub_lock.c
+++ b/lustre/lov/lovsub_lock.c
@@ -221,7 +221,11 @@ int lov_sublock_modify(const struct lu_env *env, struct lov_lock *lov,
         pd->cld_gid  = parent_descr->cld_gid;
         lovsub_lock_descr_map(d, subobj->lso_super, subobj->lso_index, pd);
 
-       /* LU-3027: only update extent of lock */
+       /* LU-3027: only update extent of lock, plus the change in
+        * lovsub_lock_delete() that lock extent is modified after a sublock
+        * is canceled, we can make sure that the lock extent won't be updated
+        * any more. Therefore, lov_lock_fits_into() will always find feasible
+        * locks */
         lov->lls_sub[idx].sub_got.cld_start = d->cld_start;
         lov->lls_sub[idx].sub_got.cld_end = d->cld_end;
         /*
@@ -300,6 +304,7 @@ static int lovsub_lock_delete_one(const struct lu_env *env,
                 RETURN(0);
 
         result = 0;
+       lov->lls_ever_canceled = 1;
         switch (parent->cll_state) {
        case CLS_ENQUEUED:
                /* See LU-1355 for the case that a glimpse lock is
@@ -419,15 +424,12 @@ static void lovsub_lock_delete(const struct lu_env *env,
                 struct lov_lock      *lov;
                 struct lov_lock_link *scan;
                 struct lov_lock_link *temp;
-                struct lov_lock_sub  *subdata;
 
                 restart = 0;
                 cfs_list_for_each_entry_safe(scan, temp,
                                              &sub->lss_parents, lll_list) {
                         lov     = scan->lll_super;
-                        subdata = &lov->lls_sub[scan->lll_idx];
                         lovsub_parent_lock(env, lov);
-                        subdata->sub_got = subdata->sub_descr;
                         lov_lock_unlink(env, scan, sub);
                         restart = lovsub_lock_delete_one(env, child, lov);
                         lovsub_parent_unlock(env, lov);