From: Olaf Faaland <faaland1@llnl.gov>
Date: Tue, 27 Oct 2015 00:51:46 +0000 (-0700)
Subject: LU-7345 obdclass: annotate locks in __local_file_create
X-Git-Tag: 2.7.63~2
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=953e9e5e75ca12a5ef72bfe844c1216341af12c9

LU-7345 obdclass: annotate locks in __local_file_create

dt_write_lock() is called for both the child and the parent dt_objects
when a directory is created.  This triggers a false positive in
lockdep when running with CONFIG_LOCKDEP=y, as the structure
containing the lock and the name of the lock is the same, and so it
appears to be a recursive lock attempt based on lock class.

This gives the two locks different subclasses so lockdep can
differentiate between them.

Also, osd-zfs osd_object_{read,write}_lock() functions currently
ignore the subclass (role) provided by the caller, calling down_read()
instead of down_read_nested() for example.

Make osd_zfs use the _nested variants so the role takes effect.

Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Change-Id: Iab79feadfbd7d1a5a06749ecb9f6888b55a78d73
Reviewed-on: http://review.whamcloud.com/16957
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---

diff --git a/lustre/obdclass/local_storage.c b/lustre/obdclass/local_storage.c
index d124690..317c776 100644
--- a/lustre/obdclass/local_storage.c
+++ b/lustre/obdclass/local_storage.c
@@ -368,7 +368,7 @@ static struct dt_object *__local_file_create(const struct lu_env *env,
 	if (rc)
 		GOTO(trans_stop, rc);
 
-	dt_write_lock(env, dto, 0);
+	dt_write_lock(env, dto, LOS_CHILD);
 	if (dt_object_exists(dto))
 		GOTO(unlock, rc = 0);
 
@@ -399,7 +399,7 @@ static struct dt_object *__local_file_create(const struct lu_env *env,
 
 	rec->rec_fid = fid;
 	rec->rec_type = dto->do_lu.lo_header->loh_attr;
-	dt_write_lock(env, parent, 0);
+	dt_write_lock(env, parent, LOS_PARENT);
 	rc = dt_insert(env, parent, (const struct dt_rec *)rec,
 		       (const struct dt_key *)name, th, 1);
 	if (dti->dti_dof.dof_type == DFT_DIR)
diff --git a/lustre/obdclass/local_storage.h b/lustre/obdclass/local_storage.h
index 7ff6faa..caf26bf 100644
--- a/lustre/obdclass/local_storage.h
+++ b/lustre/obdclass/local_storage.h
@@ -91,4 +91,12 @@ struct los_ondisk {
 
 #define LOS_MAGIC	0xdecafbee
 
+/**
+ * Used in __local_file_create() for object lock role
+ **/
+enum los_object_role {
+	LOS_PARENT,
+	LOS_CHILD,
+};
+
 #endif
diff --git a/lustre/osd-zfs/osd_object.c b/lustre/osd-zfs/osd_object.c
index 5c2d1f5..2dc0370 100644
--- a/lustre/osd-zfs/osd_object.c
+++ b/lustre/osd-zfs/osd_object.c
@@ -660,7 +660,7 @@ static void osd_object_read_lock(const struct lu_env *env,
 
 	LASSERT(osd_invariant(obj));
 
-	down_read(&obj->oo_sem);
+	down_read_nested(&obj->oo_sem, role);
 }
 
 static void osd_object_write_lock(const struct lu_env *env,
@@ -670,7 +670,7 @@ static void osd_object_write_lock(const struct lu_env *env,
 
 	LASSERT(osd_invariant(obj));
 
-	down_write(&obj->oo_sem);
+	down_write_nested(&obj->oo_sem, role);
 }
 
 static void osd_object_read_unlock(const struct lu_env *env,