staging/lustre/ptlrpc: Fix race during exp_flock_hash creation

During race exp_flock_hash can be created 2 times.
It is created & assigned without any lock.

Move hash initialization from ldlm_flock_blocking_link()
to ldlm_init_export()

Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2835
Lustre-change: http://review.whamcloud.com/5471
Signed-off-by: Andriy Skulysh <Andriy_Skulysh@xyratex.com>
Reviewed-by: Alexander Boyko <Alexander_Boyko@xyratex.com>
Reviewed-by: Vitaly Fertman <Vitaly_Fertman@xyratex.com>
Tested-by: Kyrylo Shatskyy <kyrylo_shatskyy@xyratex.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Reviewed-by: Prakash Surya <surya1@llnl.gov>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c b/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c
index 456d5aa76960f7aa4c62f498d1331f6f8900f479..c9aae132f98ae254bd213657a4304a940c9040fc 100644 (file)
--- a/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c
+++ b/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c
@@ -95,20 +95,12 @@ ldlm_flocks_overlap(struct ldlm_lock *lock, struct ldlm_lock *new)
                lock->l_policy_data.l_flock.start));
 }
 
-static inline int ldlm_flock_blocking_link(struct ldlm_lock *req,
-                                          struct ldlm_lock *lock)
+static inline void ldlm_flock_blocking_link(struct ldlm_lock *req,
+                                           struct ldlm_lock *lock)
 {
-       int rc = 0;
-
        /* For server only */
        if (req->l_export == NULL)
-               return 0;
-
-       if (unlikely(req->l_export->exp_flock_hash == NULL)) {
-               rc = ldlm_init_flock_export(req->l_export);
-               if (rc)
-                       goto error;
-       }
+               return;
 
        LASSERT(hlist_unhashed(&req->l_exp_flock_hash));
 
@@ -121,8 +113,6 @@ static inline int ldlm_flock_blocking_link(struct ldlm_lock *req,
        cfs_hash_add(req->l_export->exp_flock_hash,
                     &req->l_policy_data.l_flock.owner,
                     &req->l_exp_flock_hash);
-error:
-       return rc;
 }
 
 static inline void ldlm_flock_blocking_unlink(struct ldlm_lock *req)
@@ -250,7 +240,6 @@ ldlm_process_flock_lock(struct ldlm_lock *req, __u64 *flags, int first_enq,
        int overlaps = 0;
        int splitted = 0;
        const struct ldlm_callback_suite null_cbs = { NULL };
-       int rc;
 
        CDEBUG(D_DLMTRACE, "flags %#llx owner "LPU64" pid %u mode %u start "
               LPU64" end "LPU64"\n", *flags,
@@ -328,12 +317,8 @@ reprocess:
 
                        /* add lock to blocking list before deadlock
                         * check to prevent race */
-                       rc = ldlm_flock_blocking_link(req, lock);
-                       if (rc) {
-                               ldlm_flock_destroy(req, mode, *flags);
-                               *err = rc;
-                               return LDLM_ITER_STOP;
-                       }
+                       ldlm_flock_blocking_link(req, lock);
+
                        if (ldlm_flock_deadlock(req, lock)) {
                                ldlm_flock_blocking_unlink(req);
                                ldlm_flock_destroy(req, mode, *flags);
@@ -813,6 +798,9 @@ static cfs_hash_ops_t ldlm_export_flock_ops = {
 
 int ldlm_init_flock_export(struct obd_export *exp)
 {
+       if (strcmp(exp->exp_obd->obd_type->typ_name, LUSTRE_MDT_NAME) != 0)
+               return 0;
+
        exp->exp_flock_hash =
                cfs_hash_create(obd_uuid2str(&exp->exp_client_uuid),
                                HASH_EXP_LOCK_CUR_BITS,

diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_lockd.c b/drivers/staging/lustre/lustre/ldlm/ldlm_lockd.c
index bbf42914b76532d415ced9c909188795bbfb10b9..85f5e7e42486a5c415e0bef4313ac140ea622628 100644 (file)
--- a/drivers/staging/lustre/lustre/ldlm/ldlm_lockd.c
+++ b/drivers/staging/lustre/lustre/ldlm/ldlm_lockd.c
@@ -964,6 +964,7 @@ static cfs_hash_ops_t ldlm_export_lock_ops = {
 
 int ldlm_init_export(struct obd_export *exp)
 {
+       int rc;
        exp->exp_lock_hash =
                cfs_hash_create(obd_uuid2str(&exp->exp_client_uuid),
                                HASH_EXP_LOCK_CUR_BITS,
@@ -977,7 +978,14 @@ int ldlm_init_export(struct obd_export *exp)
        if (!exp->exp_lock_hash)
                return -ENOMEM;
 
+       rc = ldlm_init_flock_export(exp);
+       if (rc)
+               GOTO(err, rc);
+
        return 0;
+err:
+       ldlm_destroy_export(exp);
+       return rc;
 }
 EXPORT_SYMBOL(ldlm_init_export);