diff --git a/fs/block_dev.c b/fs/block_dev.c
index 2db79b6d5e6b8e9c1ff2663ea7f9cfa863516e70..5f58e1a604a05f64c98f843b66b2317043a662e1 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -2007,6 +2007,9 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (bdev_read_only(I_BDEV(bd_inode)))
 		return -EPERM;
 
+	if (IS_SWAPFILE(bd_inode))
+		return -ETXTBSY;
+
 	if (!iov_iter_count(from))
 		return 0;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 787c8cd420a02c38b06741fb7da91abf167721b2..118021c316da0a18adb36d1f831be2929d7ef6b0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3550,4 +3550,15 @@ extern int vfs_fadvise(struct file *file, loff_t offset, loff_t len,
 extern int generic_fadvise(struct file *file, loff_t offset, loff_t len,
 			   int advice);
 
+/*
+ * Flush file data before changing attributes.  Caller must hold any locks
+ * required to prevent further writes to this file until we're done setting
+ * flags.
+ */
+static inline int inode_drain_writes(struct inode *inode)
+{
+	inode_dio_wait(inode);
+	return filemap_write_and_wait(inode->i_mapping);
+}
+
 #endif /* _LINUX_FS_H */
diff --git a/mm/filemap.c b/mm/filemap.c
index 52e888f8de49beacbf925288f82a5eeba2394707..b4f919d487d154c2a7ffee1221ffe862b338dcca 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3052,6 +3052,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
 	unsigned long limit = rlimit(RLIMIT_FSIZE);
 	loff_t pos;
 
+	if (IS_SWAPFILE(inode))
+		return -ETXTBSY;
+
 	if (!iov_iter_count(from))
 		return 0;
 
diff --git a/mm/memory.c b/mm/memory.c
index d146d4231686a4cb87293129365b3249b792b0b2..0ff363795cbd95a4af3556cdb1c7aff42e1450dd 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2226,6 +2226,10 @@ static vm_fault_t do_page_mkwrite(struct vm_fault *vmf)
 
 	vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
 
+	if (vmf->vma->vm_file &&
+	    IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host))
+		return VM_FAULT_SIGBUS;
+
 	ret = vmf->vma->vm_ops->page_mkwrite(vmf);
 	/* Restore original flags so that caller is not surprised */
 	vmf->flags = old_flags;
diff --git a/mm/mmap.c b/mm/mmap.c
index 04e34c0227755d36fff7740d1200e78c281e7e8f..3fcfed26d298cbbbb08b6338ee13ae7c3382127b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1486,8 +1486,12 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
 		case MAP_SHARED_VALIDATE:
 			if (flags & ~flags_mask)
 				return -EOPNOTSUPP;
-			if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
-				return -EACCES;
+			if (prot & PROT_WRITE) {
+				if (!(file->f_mode & FMODE_WRITE))
+					return -EACCES;
+				if (IS_SWAPFILE(file->f_mapping->host))
+					return -ETXTBSY;
+			}
 
 			/*
 			 * Make sure we don't allow writing to an append-only
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 06df64e59d9cecf68744dd383b416a2549a602f7..c03de4f1ee770222d588c731ab165ca5d7f482e2 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3384,6 +3384,17 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	if (error)
 		goto bad_swap;
 
+	/*
+	 * Flush any pending IO and dirty mappings before we start using this
+	 * swap device.
+	 */
+	inode->i_flags |= S_SWAPFILE;
+	error = inode_drain_writes(inode);
+	if (error) {
+		inode->i_flags &= ~S_SWAPFILE;
+		goto bad_swap;
+	}
+
 	mutex_lock(&swapon_mutex);
 	prio = -1;
 	if (swap_flags & SWAP_FLAG_PREFER)
@@ -3404,7 +3415,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	atomic_inc(&proc_poll_event);
 	wake_up_interruptible(&proc_poll_wait);
 
-	inode->i_flags |= S_SWAPFILE;
 	error = 0;
 	goto out;
 bad_swap: