3 files changed, 27 insertions, 10 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 5ff3e9a4fe5f..5beed7b30561 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -584,9 +584,10 @@ static inline struct dentry *d_real(struct dentry *dentry,
  * If dentry is on an union/overlay, then return the underlying, real inode.
  * Otherwise return d_inode().
  */
-static inline struct inode *d_real_inode(struct dentry *dentry)
+static inline struct inode *d_real_inode(const struct dentry *dentry)
 {
-	return d_backing_inode(d_real(dentry, NULL, 0));
+	/* This usage of d_real() results in const dentry */
+	return d_backing_inode(d_real((struct dentry *) dentry, NULL, 0));
 }
 
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2f6f059d739c..9347f4a2abed 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -224,6 +224,7 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 #define ATTR_KILL_PRIV	(1 << 14)
 #define ATTR_OPEN	(1 << 15) /* Truncating from open(O_TRUNC) */
 #define ATTR_TIMES_SET	(1 << 16)
+#define ATTR_TOUCH	(1 << 17)
 
 /*
  * Whiteout is represented by a char device.  The following constants define the
@@ -1064,6 +1065,18 @@ struct file_lock_context {
 
 extern void send_sigio(struct fown_struct *fown, int fd, int band);
 
+/*
+ * Return the inode to use for locking
+ *
+ * For overlayfs this should be the overlay inode, not the real inode returned
+ * by file_inode().  For any other fs file_inode(filp) and locks_inode(filp) are
+ * equal.
+ */
+static inline struct inode *locks_inode(const struct file *f)
+{
+	return f->f_path.dentry->d_inode;
+}
+
 #ifdef CONFIG_FILE_LOCKING
 extern int fcntl_getlk(struct file *, unsigned int, struct flock __user *);
 extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
@@ -1251,7 +1264,7 @@ static inline struct dentry *file_dentry(const struct file *file)
 
 static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
 {
-	return locks_lock_inode_wait(file_inode(filp), fl);
+	return locks_lock_inode_wait(locks_inode(filp), fl);
 }
 
 struct fasync_struct {
@@ -2006,7 +2019,6 @@ enum file_time_flags {
 	S_VERSION = 8,
 };
 
-extern bool atime_needs_update(const struct path *, struct inode *);
 extern void touch_atime(const struct path *);
 static inline void file_accessed(struct file *file)
 {
@@ -2155,7 +2167,7 @@ static inline int mandatory_lock(struct inode *ino)
 
 static inline int locks_verify_locked(struct file *file)
 {
-	if (mandatory_lock(file_inode(file)))
+	if (mandatory_lock(locks_inode(file)))
 		return locks_mandatory_locked(file);
 	return 0;
 }
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index eed9e853a06f..b8bcc058e031 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -29,7 +29,11 @@ static inline int fsnotify_parent(struct path *path, struct dentry *dentry, __u3
 static inline int fsnotify_perm(struct file *file, int mask)
 {
 	struct path *path = &file->f_path;
-	struct inode *inode = file_inode(file);
+	/*
+	 * Do not use file_inode() here or anywhere in this file to get the
+	 * inode.  That would break *notity on overlayfs.
+	 */
+	struct inode *inode = path->dentry->d_inode;
 	__u32 fsnotify_mask = 0;
 	int ret;
 
@@ -173,7 +177,7 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 static inline void fsnotify_access(struct file *file)
 {
 	struct path *path = &file->f_path;
-	struct inode *inode = file_inode(file);
+	struct inode *inode = path->dentry->d_inode;
 	__u32 mask = FS_ACCESS;
 
 	if (S_ISDIR(inode->i_mode))
@@ -191,7 +195,7 @@ static inline void fsnotify_access(struct file *file)
 static inline void fsnotify_modify(struct file *file)
 {
 	struct path *path = &file->f_path;
-	struct inode *inode = file_inode(file);
+	struct inode *inode = path->dentry->d_inode;
 	__u32 mask = FS_MODIFY;
 
 	if (S_ISDIR(inode->i_mode))
@@ -209,7 +213,7 @@ static inline void fsnotify_modify(struct file *file)
 static inline void fsnotify_open(struct file *file)
 {
 	struct path *path = &file->f_path;
-	struct inode *inode = file_inode(file);
+	struct inode *inode = path->dentry->d_inode;
 	__u32 mask = FS_OPEN;
 
 	if (S_ISDIR(inode->i_mode))
@@ -225,7 +229,7 @@ static inline void fsnotify_open(struct file *file)
 static inline void fsnotify_close(struct file *file)
 {
 	struct path *path = &file->f_path;
-	struct inode *inode = file_inode(file);
+	struct inode *inode = path->dentry->d_inode;
 	fmode_t mode = file->f_mode;
 	__u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;