[PATCH v2 10/14] fsnotify: Introduce helpers to send error_events

[Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>]

Introduce helpers for filesystems interested in reporting FS_ERROR
events.

Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>

---
Changes since v1:
  - Use the inode argument (Amir)
  - Protect s_fsnotify_marks with ifdef guard
---
 fs/notify/fsnotify.c             |  2 +-
 include/linux/fsnotify.h         | 20 ++++++++++++++++++++
 include/linux/fsnotify_backend.h |  1 +
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 36205a769dde..ac05eb3fb368 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -491,7 +491,7 @@ int __fsnotify(__u32 mask, const struct fsnotify_event_info *event_info)
 		 */
 		parent = event_info->dir;
 	}
-	sb = inode->i_sb;
+	sb = event_info->sb ?: inode->i_sb;
 
 	/*
 	 * Optimization: srcu_read_lock() has a memory barrier which can
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 8c2c681b4495..c0dbc5a65381 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -326,4 +326,24 @@ static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
 		fsnotify_dentry(dentry, mask);
 }
 
+static inline int fsnotify_sb_error(struct super_block *sb, struct inode *inode,
+					int error)
+{
+#ifdef CONFIG_FSNOTIFY
+	if (sb->s_fsnotify_marks) {
+		struct fs_error_report report = {
+			.error = error,
+			.inode = inode,
+		};
+
+		return __fsnotify(FS_ERROR, &(struct fsnotify_event_info) {
+				.data = &report,
+				.data_type = FSNOTIFY_EVENT_ERROR,
+				.inode = NULL, .cookie = 0, .sb = sb
+			});
+	}
+#endif
+	return 0;
+}
+
 #endif	/* _LINUX_FS_NOTIFY_H */
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index ea5f5c7cc381..5a32c5010f45 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -138,6 +138,7 @@ struct fsnotify_event_info {
 	struct inode *dir;
 	const struct qstr *name;
 	struct inode *inode;
+	struct super_block *sb;
 	u32 cookie;
 };
 
-- 
2.31.0