LU-10949 mdt: lost reference on mdt_md_root

mdt_remote_object_lock_try() drops object
reference in case of an error but if the
request was sent to a server it is decreased
again via failed_lock_cleanup()

Add ldlm_created_callback. It is called after
lock creation, so we can safely add a reference
to l_ast_data and drop it only in BL AST handler.

Lustre-commit: b2368774a01eb89981e2ceb92be9673e4b403d62
Lustre-change: https://review.whamcloud.com/34181

Cray-bug-id: LUS-7013
Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Signed-off-by: Andriy Skulysh <c17819@cray.com>
Reviewed-by: Alexandr Boyko <c17825@cray.com>
Reviewed-by: Vitaly Fertman <c17818@cray.com>
Reviewed-by: Mike Pershin <mpershin@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Change-Id: I49c946278f379390634642370d15c7fe89441d86
Reviewed-on: https://review.whamcloud.com/39976
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>

diff --git a/lustre/include/lustre_dlm.h b/lustre/include/lustre_dlm.h
index 8dcdbfe..f47a8ac 100644 (file)
--- a/lustre/include/lustre_dlm.h
+++ b/lustre/include/lustre_dlm.h
@@ -592,6 +592,9 @@ typedef int (*ldlm_completion_callback)(struct ldlm_lock *lock, __u64 flags,
 /** Type for glimpse callback function of a lock. */
 typedef int (*ldlm_glimpse_callback)(struct ldlm_lock *lock, void *data);
 
+/** Type for created callback function of a lock. */
+typedef void (*ldlm_created_callback)(struct ldlm_lock *lock);
+
 /** Work list for sending GL ASTs to multiple locks. */
 struct ldlm_glimpse_work {
        struct ldlm_lock        *gl_lock; /* lock to glimpse */
@@ -1197,6 +1200,7 @@ struct ldlm_enqueue_info {
        void            *ei_cb_local_bl; /** blocking local lock callback */
        void            *ei_cb_cp;      /** lock completion callback */
        void            *ei_cb_gl;      /** lock glimpse callback */
+       ldlm_created_callback ei_cb_created;    /** lock created callback */
        void            *ei_cbdata;     /** Data to be passed into callbacks. */
        void            *ei_namespace;  /** lock namespace **/
        u64             ei_inodebits;   /** lock inode bits **/

diff --git a/lustre/ldlm/ldlm_request.c b/lustre/ldlm/ldlm_request.c
index f55ec91..566db66 100644 (file)
--- a/lustre/ldlm/ldlm_request.c
+++ b/lustre/ldlm/ldlm_request.c
@@ -944,6 +944,10 @@ int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
                                        lvb_len, lvb_type);
                if (IS_ERR(lock))
                        RETURN(PTR_ERR(lock));
+
+               if (einfo->ei_cb_created)
+                       einfo->ei_cb_created(lock);
+
                 /* for the local lock, add the reference */
                 ldlm_lock_addref_internal(lock, einfo->ei_mode);
                 ldlm_lock2handle(lock, lockh);

diff --git a/lustre/mdt/mdt_handler.c b/lustre/mdt/mdt_handler.c
index 7afbf3e..bd3bfe7 100644 (file)
--- a/lustre/mdt/mdt_handler.c
+++ b/lustre/mdt/mdt_handler.c
@@ -3115,6 +3115,11 @@ int mdt_check_resent_lock(struct mdt_thread_info *info,
        return 1;
 }
 
+static void mdt_remote_object_lock_created_cb(struct ldlm_lock *lock)
+{
+       mdt_object_get(NULL, lock->l_ast_data);
+}
+
 int mdt_remote_object_lock_try(struct mdt_thread_info *mti,
                               struct mdt_object *o, const struct lu_fid *fid,
                               struct lustre_handle *lh, enum ldlm_mode mode,
@@ -3143,8 +3148,8 @@ int mdt_remote_object_lock_try(struct mdt_thread_info *mti,
                 * if we cache lock, couple lock with mdt_object, so that object
                 * can be easily found in lock ASTs.
                 */
-               mdt_object_get(mti->mti_env, o);
                einfo->ei_cbdata = o;
+               einfo->ei_cb_created = mdt_remote_object_lock_created_cb;
        }
 
        memset(policy, 0, sizeof(*policy));
@@ -3153,8 +3158,6 @@ int mdt_remote_object_lock_try(struct mdt_thread_info *mti,
 
        rc = mo_object_lock(mti->mti_env, mdt_object_child(o), lh, einfo,
                            policy);
-       if (rc < 0 && cache)
-               mdt_object_put(mti->mti_env, o);
 
        /* Return successfully acquired bits to a caller */
        if (rc == 0) {