diff --git a/fs/locks.c b/fs/locks.c
index 9edfec4..ebe9a30 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -605,12 +605,86 @@ static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *s
 	return (locks_conflict(caller_fl, sys_fl));
 }
 
-/* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
+static unsigned int
+deny_flags_to_cmd(unsigned int flags)
+{
+	unsigned int cmd = LOCK_MAND;
+
+	if (!(flags & O_DENYREAD))
+		cmd |= LOCK_READ;
+	if (!(flags & O_DENYWRITE))
+		cmd |= LOCK_WRITE;
+
+	return cmd;
+}
+
+/*
+ * locks_mand_conflict - Determine if there's a share reservation conflict
+ * @caller_fl: lock we're attempting to acquire
+ * @sys_fl: lock already present on system that we're checking against
+ *
+ * Check to see if there's a share_reservation conflict. LOCK_READ/LOCK_WRITE
+ * tell us whether the reservation allows other readers and writers.
+ *
+ * We only check against other LOCK_MAND locks, so applications that want to
+ * use share mode locking will only conflict against one another. "normal"
+ * applications that open files won't be affected by and won't themselves
+ * affect the share reservations.
+ */
+static int
+locks_mand_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
+{
+	unsigned char caller_type = caller_fl->fl_type;
+	unsigned char sys_type = sys_fl->fl_type;
+	fmode_t caller_fmode = caller_fl->fl_file->f_mode;
+	fmode_t sys_fmode = sys_fl->fl_file->f_mode;
+
+	/* they can only conflict if they're both LOCK_MAND */
+	if (!(caller_type & LOCK_MAND) || !(sys_type & LOCK_MAND))
+		return 0;
+
+	if (!(caller_type & LOCK_READ) && (sys_fmode & FMODE_READ))
+		return 1;
+	if (!(caller_type & LOCK_WRITE) && (sys_fmode & FMODE_WRITE))
+		return 1;
+	if (!(sys_type & LOCK_READ) && (caller_fmode & FMODE_READ))
+		return 1;
+	if (!(sys_type & LOCK_WRITE) && (caller_fmode & FMODE_WRITE))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Determine if lock sys_fl blocks lock caller_fl. O_DENY* flags specific
+ * checking before calling the locks_conflict().
+ */
+static int
+deny_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
+{
+	/*
+	 * FLOCK locks referring to the same filp do not conflict with
+	 * each other.
+	 */
+	if (!IS_FLOCK(sys_fl))
+		return 0;
+	if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
+		return locks_mand_conflict(caller_fl, sys_fl);
+	if (caller_fl->fl_file == sys_fl->fl_file)
+		return 0;
+
+	return locks_conflict(caller_fl, sys_fl);
+}
+
+/*
+ * Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
  * checking before calling the locks_conflict().
  */
-static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
+static int
+flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
 {
-	/* FLOCK locks referring to the same filp do not conflict with
+	/*
+	 * FLOCK locks referring to the same filp do not conflict with
 	 * each other.
 	 */
 	if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file))
@@ -789,6 +863,32 @@ out:
 	return error;
 }
 
+/*
+ * Determine if a file is allowed to be opened with specified access and deny
+ * modes. Lock the file and return 0 if checks passed, otherwise return a error
+ * code.
+ */
+int
+deny_lock_file(struct file *filp)
+{
+	struct file_lock *lock;
+	int error = 0;
+
+	if (!(filp->f_flags & O_DENYMAND))
+		return error;
+
+	error = flock_make_lock(filp, &lock, deny_flags_to_cmd(filp->f_flags));
+	if (error)
+		return error;
+
+	error = flock_lock_file(filp, lock, deny_locks_conflict);
+	if (error == -EAGAIN)
+		error = -ETXTBSY;
+
+	locks_free_lock(lock);
+	return error;
+}
+
 static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
 {
 	struct file_lock *fl;
diff --git a/fs/namei.c b/fs/namei.c
index 5f4cdf3..bf3bb34 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2569,9 +2569,14 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
 	 * here.
 	 */
 	error = may_open(&file->f_path, acc_mode, open_flag);
-	if (error)
+	if (error) {
 		fput(file);
+		goto out;
+	}
 
+	error = deny_lock_file(file);
+	if (error)
+		fput(file);
 out:
 	dput(dentry);
 	return error;
@@ -2908,6 +2913,9 @@ opened:
 		if (error)
 			goto exit_fput;
 	}
+	error = deny_lock_file(file);
+	if (error)
+		goto exit_fput;
 out:
 	if (got_write)
 		mnt_drop_write(nd->path.mnt);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 70a766ae..b8ed06e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1004,6 +1004,7 @@ extern int lease_modify(struct file_lock **, int);
 extern int lock_may_read(struct inode *, loff_t start, unsigned long count);
 extern int lock_may_write(struct inode *, loff_t start, unsigned long count);
 extern void locks_delete_block(struct file_lock *waiter);
+extern int deny_lock_file(struct file *);
 extern void lock_flocks(void);
 extern void unlock_flocks(void);
 #else /* !CONFIG_FILE_LOCKING */
@@ -1152,6 +1153,11 @@ static inline void locks_delete_block(struct file_lock *waiter)
 {
 }
 
+static inline int deny_lock_file(struct file *filp)
+{
+	return 0;
+}
+
 static inline void lock_flocks(void)
 {
 }
