[v1,09/38] fsnotify: add a srcu barrier for fsnotify

Commit Message

Jeff Layton Nov. 17, 2015, 11:52 a.m. UTC

For nfsd, we'll need to be able to ensure that all fsnotify_mark
callbacks have run before we can tear down the nfsd_file_mark_cache.
That's simple now that we're using call_srcu directly. Just use
srcu_barrier to ensure that all the callbacks have completed.

Signed-off-by: Jeff Layton <[e-mail]>
---
 fs/notify/mark.c                 | 7 +++++++
 include/linux/fsnotify_backend.h | 2 ++
 2 files changed, 9 insertions(+)

Patch

diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 00e7072d3c95..6b6b99447348 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -204,6 +204,13 @@  void fsnotify_free_mark(struct fsnotify_mark *mark)
 		group->ops->freeing_mark(mark, group);
 }
 
+void
+fsnotify_srcu_barrier(void)
+{
+	srcu_barrier(&fsnotify_mark_srcu);
+}
+EXPORT_SYMBOL_GPL(fsnotify_srcu_barrier);
+
 void fsnotify_destroy_mark(struct fsnotify_mark *mark,
 			   struct fsnotify_group *group)
 {
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 1c582747b410..b211eda20842 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -360,6 +360,8 @@  extern void fsnotify_destroy_mark(struct fsnotify_mark *mark,
 extern void fsnotify_detach_mark(struct fsnotify_mark *mark);
 /* free mark */
 extern void fsnotify_free_mark(struct fsnotify_mark *mark);
+/* wait for all in-flight fsnotify srcu callbacks to run */
+extern void fsnotify_srcu_barrier(void);
 /* run all the marks in a group, and clear all of the vfsmount marks */
 extern void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group);
 /* run all the marks in a group, and clear all of the inode marks */