3 files changed, 27 insertions, 4 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5f7ac5b548a4..3f4d59464965 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1265,6 +1265,7 @@ extern int send_sigurg(struct file *file);
 #define SB_I_RETIRED	0x00000800	/* superblock shouldn't be reused */
 #define SB_I_NOUMASK	0x00001000	/* VFS does not apply umask */
 #define SB_I_NOIDMAP	0x00002000	/* No idmapped mounts on this superblock */
+#define SB_I_ALLOW_HSM	0x00004000	/* Allow HSM events on this superblock */
 
 /* Possible states of 'frozen' field */
 enum {
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 8d1849137a96..d91aa064f0e4 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -144,12 +144,29 @@ static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,
 	 */
 	lockdep_assert_once(file_write_not_started(file));
 
-	if (!(perm_mask & MAY_READ))
+	if (!(perm_mask & (MAY_READ | MAY_WRITE | MAY_ACCESS)))
 		return 0;
 
 	if (likely(!FMODE_FSNOTIFY_PERM(file->f_mode)))
 		return 0;
 
+	/*
+	 * read()/write() and other types of access generate pre-content events.
+	 */
+	if (unlikely(FMODE_FSNOTIFY_HSM(file->f_mode))) {
+		int ret = fsnotify_path(&file->f_path, FS_PRE_ACCESS);
+
+		if (ret)
+			return ret;
+	}
+
+	if (!(perm_mask & MAY_READ))
+		return 0;
+
+	/*
+	 * read() also generates the legacy FS_ACCESS_PERM event, so content
+	 * scanners can inspect the content filled by pre-content event.
+	 */
 	return fsnotify_path(&file->f_path, FS_ACCESS_PERM);
 }
 
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index c38762b62bf1..9bda354b5538 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -57,6 +57,8 @@
 #define FS_OPEN_EXEC_PERM	0x00040000	/* open/exec event in a permission hook */
 /* #define FS_DIR_MODIFY	0x00080000 */	/* Deprecated (reserved) */
 
+#define FS_PRE_ACCESS		0x00100000	/* Pre-content access hook */
+
 /*
  * Set on inode mark that cares about things that happen to its children.
  * Always set for dnotify and inotify.
@@ -78,11 +80,14 @@
  */
 #define ALL_FSNOTIFY_DIRENT_EVENTS (FS_CREATE | FS_DELETE | FS_MOVE | FS_RENAME)
 
+/* Content events can be used to inspect file content */
+#define FSNOTIFY_CONTENT_PERM_EVENTS (FS_OPEN_PERM | FS_OPEN_EXEC_PERM | \
+				      FS_ACCESS_PERM)
 /* Pre-content events can be used to fill file content */
-#define FSNOTIFY_PRE_CONTENT_EVENTS 0
+#define FSNOTIFY_PRE_CONTENT_EVENTS  (FS_PRE_ACCESS)
 
-#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM | \
-				  FS_OPEN_EXEC_PERM)
+#define ALL_FSNOTIFY_PERM_EVENTS (FSNOTIFY_CONTENT_PERM_EVENTS | \
+				  FSNOTIFY_PRE_CONTENT_EVENTS)
 
 /*
  * This is a list of all events that may get sent to a parent that is watching