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authorJan Kara <jack@suse.cz>2016-11-10 16:02:11 +0100
committerJan Kara <jack@suse.cz>2017-04-10 17:37:36 +0200
commitabc77577a669f424c5d0c185b9994f2621c52aa4 (patch)
treea7e18bc2c8229a8a634d899445c33958f8967876 /include/linux/fsnotify_backend.h
parentf09b04a03e0239f65bd964a1de758e53cf6349e8 (diff)
fsnotify: Provide framework for dropping SRCU lock in ->handle_event
fanotify wants to drop fsnotify_mark_srcu lock when waiting for response from userspace so that the whole notification subsystem is not blocked during that time. This patch provides a framework for safely getting mark reference for a mark found in the object list which pins the mark in that list. We can then drop fsnotify_mark_srcu, wait for userspace response and then safely continue iteration of the object list once we reaquire fsnotify_mark_srcu. Reviewed-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'include/linux/fsnotify_backend.h')
-rw-r--r--include/linux/fsnotify_backend.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index a483614b25d0..5bb6d988b9f6 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -80,6 +80,7 @@ struct fsnotify_event;
struct fsnotify_mark;
struct fsnotify_event_private_data;
struct fsnotify_fname;
+struct fsnotify_iter_info;
/*
* Each group much define these ops. The fsnotify infrastructure will call
@@ -163,6 +164,8 @@ struct fsnotify_group {
struct fsnotify_event *overflow_event; /* Event we queue when the
* notification list is too
* full */
+ atomic_t user_waits; /* Number of tasks waiting for user
+ * response */
/* groups can define private fields here or use the void *private */
union {
@@ -368,6 +371,8 @@ extern void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, un
extern void fsnotify_get_mark(struct fsnotify_mark *mark);
extern void fsnotify_put_mark(struct fsnotify_mark *mark);
extern void fsnotify_unmount_inodes(struct super_block *sb);
+extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info);
+extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info);
/* put here because inotify does some weird stuff when destroying watches */
extern void fsnotify_init_event(struct fsnotify_event *event,