Merge branch 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull fsnotify updates from Jan Kara:
 "The branch contains mainly a rework of fsnotify infrastructure fixing
  a shortcoming that we have waited for response to fanotify permission
  events with SRCU read lock held and when the process consuming events
  was slow to respond the kernel has stalled.

  It also contains several cleanups of unnecessary indirections in
  fsnotify framework and a bugfix from Amir fixing leakage of kernel
  internal errno to userspace"

* 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: (37 commits)
  fanotify: don't expose EOPENSTALE to userspace
  fsnotify: remove a stray unlock
  fsnotify: Move ->free_mark callback to fsnotify_ops
  fsnotify: Add group pointer in fsnotify_init_mark()
  fsnotify: Drop inode_mark.c
  fsnotify: Remove fsnotify_find_{inode|vfsmount}_mark()
  fsnotify: Remove fsnotify_detach_group_marks()
  fsnotify: Rename fsnotify_clear_marks_by_group_flags()
  fsnotify: Inline fsnotify_clear_{inode|vfsmount}_mark_group()
  fsnotify: Remove fsnotify_recalc_{inode|vfsmount}_mask()
  fsnotify: Remove fsnotify_set_mark_{,ignored_}mask_locked()
  fanotify: Release SRCU lock when waiting for userspace response
  fsnotify: Pass fsnotify_iter_info into handle_event handler
  fsnotify: Provide framework for dropping SRCU lock in ->handle_event
  fsnotify: Remove special handling of mark destruction on group shutdown
  fsnotify: Detach mark from object list when last reference is dropped
  fsnotify: Move queueing of mark for destruction into fsnotify_put_mark()
  inotify: Do not drop mark reference under idr_lock
  fsnotify: Free fsnotify_mark_connector when there is no mark attached
  fsnotify: Lock object list with connector lock
  ...

2 files changed, 64 insertions, 35 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 30e5c14bd743..5d62d2c47939 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -546,6 +546,8 @@ is_uncached_acl(struct posix_acl *acl)
 #define IOP_XATTR	0x0008
 #define IOP_DEFAULT_READLINK	0x0010
 
+struct fsnotify_mark_connector;
+
 /*
  * Keep mostly read-only and often accessed (especially for
  * the RCU path lookup and 'stat' data) fields at the beginning
@@ -645,7 +647,7 @@ struct inode {
 
 #ifdef CONFIG_FSNOTIFY
 	__u32			i_fsnotify_mask; /* all events this inode cares about */
-	struct hlist_head	i_fsnotify_marks;
+	struct fsnotify_mark_connector __rcu	*i_fsnotify_marks;
 #endif
 
 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index e6e689b5569e..c6c69318752b 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
@@ -98,10 +99,13 @@ struct fsnotify_ops {
 			    struct fsnotify_mark *inode_mark,
 			    struct fsnotify_mark *vfsmount_mark,
 			    u32 mask, const void *data, int data_type,
-			    const unsigned char *file_name, u32 cookie);
+			    const unsigned char *file_name, u32 cookie,
+			    struct fsnotify_iter_info *iter_info);
 	void (*free_group_priv)(struct fsnotify_group *group);
 	void (*freeing_mark)(struct fsnotify_mark *mark, struct fsnotify_group *group);
 	void (*free_event)(struct fsnotify_event *event);
+	/* called on final put+free to free memory */
+	void (*free_mark)(struct fsnotify_mark *mark);
 };
 
 /*
@@ -163,6 +167,8 @@ 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 {
@@ -195,6 +201,30 @@ struct fsnotify_group {
 #define FSNOTIFY_EVENT_INODE	2
 
 /*
+ * Inode / vfsmount point to this structure which tracks all marks attached to
+ * the inode / vfsmount. The reference to inode / vfsmount is held by this
+ * structure. We destroy this structure when there are no more marks attached
+ * to it. The structure is protected by fsnotify_mark_srcu.
+ */
+struct fsnotify_mark_connector {
+	spinlock_t lock;
+#define FSNOTIFY_OBJ_TYPE_INODE		0x01
+#define FSNOTIFY_OBJ_TYPE_VFSMOUNT	0x02
+#define FSNOTIFY_OBJ_ALL_TYPES		(FSNOTIFY_OBJ_TYPE_INODE | \
+					 FSNOTIFY_OBJ_TYPE_VFSMOUNT)
+	unsigned int flags;	/* Type of object [lock] */
+	union {	/* Object pointer [lock] */
+		struct inode *inode;
+		struct vfsmount *mnt;
+	};
+	union {
+		struct hlist_head list;
+		/* Used listing heads to free after srcu period expires */
+		struct fsnotify_mark_connector *destroy_next;
+	};
+};
+
+/*
  * A mark is simply an object attached to an in core inode which allows an
  * fsnotify listener to indicate they are either no longer interested in events
  * of a type matching mask or only interested in those events.
@@ -223,22 +253,16 @@ struct fsnotify_mark {
 	struct list_head g_list;
 	/* Protects inode / mnt pointers, flags, masks */
 	spinlock_t lock;
-	/* List of marks for inode / vfsmount [obj_lock] */
+	/* List of marks for inode / vfsmount [connector->lock, mark ref] */
 	struct hlist_node obj_list;
-	union {	/* Object pointer [mark->lock, group->mark_mutex] */
-		struct inode *inode;	/* inode this mark is associated with */
-		struct vfsmount *mnt;	/* vfsmount this mark is associated with */
-	};
+	/* Head of list of marks for an object [mark ref] */
+	struct fsnotify_mark_connector *connector;
 	/* Events types to ignore [mark->lock, group->mark_mutex] */
 	__u32 ignored_mask;
-#define FSNOTIFY_MARK_FLAG_INODE		0x01
-#define FSNOTIFY_MARK_FLAG_VFSMOUNT		0x02
-#define FSNOTIFY_MARK_FLAG_OBJECT_PINNED	0x04
-#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY	0x08
-#define FSNOTIFY_MARK_FLAG_ALIVE		0x10
-#define FSNOTIFY_MARK_FLAG_ATTACHED		0x20
+#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY	0x01
+#define FSNOTIFY_MARK_FLAG_ALIVE		0x02
+#define FSNOTIFY_MARK_FLAG_ATTACHED		0x04
 	unsigned int flags;		/* flags [mark->lock] */
-	void (*free_mark)(struct fsnotify_mark *mark); /* called on final put+free */
 };
 
 #ifdef CONFIG_FSNOTIFY
@@ -315,23 +339,18 @@ extern struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group
 
 /* functions used to manipulate the marks attached to inodes */
 
-/* run all marks associated with a vfsmount and update mnt->mnt_fsnotify_mask */
-extern void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt);
-/* run all marks associated with an inode and update inode->i_fsnotify_mask */
-extern void fsnotify_recalc_inode_mask(struct inode *inode);
-extern void fsnotify_init_mark(struct fsnotify_mark *mark, void (*free_mark)(struct fsnotify_mark *mark));
-/* find (and take a reference) to a mark associated with group and inode */
-extern struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, struct inode *inode);
-/* find (and take a reference) to a mark associated with group and vfsmount */
-extern struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, struct vfsmount *mnt);
-/* set the ignored_mask of a mark */
-extern void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask);
-/* set the mask of a mark (might pin the object into memory */
-extern void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask);
-/* attach the mark to both the group and the inode */
-extern int fsnotify_add_mark(struct fsnotify_mark *mark, struct fsnotify_group *group,
-			     struct inode *inode, struct vfsmount *mnt, int allow_dups);
-extern int fsnotify_add_mark_locked(struct fsnotify_mark *mark, struct fsnotify_group *group,
+/* Calculate mask of events for a list of marks */
+extern void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn);
+extern void fsnotify_init_mark(struct fsnotify_mark *mark,
+			       struct fsnotify_group *group);
+/* Find mark belonging to given group in the list of marks */
+extern struct fsnotify_mark *fsnotify_find_mark(
+				struct fsnotify_mark_connector __rcu **connp,
+				struct fsnotify_group *group);
+/* attach the mark to the inode or vfsmount */
+extern int fsnotify_add_mark(struct fsnotify_mark *mark, struct inode *inode,
+			     struct vfsmount *mnt, int allow_dups);
+extern int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
 				    struct inode *inode, struct vfsmount *mnt, int allow_dups);
 /* given a group and a mark, flag mark to be freed when all references are dropped */
 extern void fsnotify_destroy_mark(struct fsnotify_mark *mark,
@@ -340,15 +359,23 @@ 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);
+/* run all the marks in a group, and clear all of the marks attached to given object type */
+extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group, unsigned int type);
 /* 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);
+static inline void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
+{
+	fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_VFSMOUNT);
+}
 /* run all the marks in a group, and clear all of the inode marks */
-extern void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group);
-/* run all the marks in a group, and clear all of the marks where mark->flags & flags is true*/
-extern void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, unsigned int flags);
+static inline void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group)
+{
+	fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_INODE);
+}
 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,