diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9025bab58e81..8b41ec42f405 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -712,6 +712,28 @@ struct btrfs_fs_devices;
 struct btrfs_balance_control;
 struct btrfs_delayed_root;
 
+/*
+ * Block group or device which contains an active swapfile. Used for preventing
+ * unsafe operations while a swapfile is active.
+ *
+ * These are sorted on (ptr, inode) (note that a block group or device can
+ * contain more than one swapfile). We compare the pointer values because we
+ * don't actually care what the object is, we just need a quick check whether
+ * the object exists in the rbtree.
+ */
+struct btrfs_swapfile_pin {
+	struct rb_node node;
+	void *ptr;
+	struct inode *inode;
+	/*
+	 * If true, ptr points to a struct btrfs_block_group_cache. Otherwise,
+	 * ptr points to a struct btrfs_device.
+	 */
+	bool is_block_group;
+};
+
+bool btrfs_pinned_by_swapfile(struct btrfs_fs_info *fs_info, void *ptr);
+
 #define BTRFS_FS_BARRIER			1
 #define BTRFS_FS_CLOSING_START			2
 #define BTRFS_FS_CLOSING_DONE			3
@@ -1114,6 +1136,10 @@ struct btrfs_fs_info {
 	u32 sectorsize;
 	u32 stripesize;
 
+	/* Block groups and devices containing active swapfiles. */
+	spinlock_t swapfile_pins_lock;
+	struct rb_root swapfile_pins;
+
 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 	spinlock_t ref_verify_lock;
 	struct rb_root block_tree;
@@ -1274,6 +1300,9 @@ struct btrfs_root {
 	u64 qgroup_meta_rsv_pertrans;
 	u64 qgroup_meta_rsv_prealloc;
 
+	/* Number of active swapfiles */
+	atomic_t nr_swapfiles;
+
 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 	u64 alloc_bytenr;
 #endif
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 2aa48aecc52b..46092e67f61a 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -407,6 +407,13 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 	if (IS_ERR(src_device))
 		return PTR_ERR(src_device);
 
+	if (btrfs_pinned_by_swapfile(fs_info, src_device)) {
+		btrfs_warn_in_rcu(fs_info,
+	  "cannot replace device %s (devid %llu) due to active swapfile",
+			btrfs_dev_name(src_device), src_device->devid);
+		return -ETXTBSY;
+	}
+
 	ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
 					    src_device, &tgt_device);
 	if (ret)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 6d776717d8b3..c1d127decc8d 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1178,6 +1178,7 @@ static void __setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
 	refcount_set(&root->refs, 1);
 	atomic_set(&root->will_be_snapshotted, 0);
 	atomic_set(&root->snapshot_force_cow, 0);
+	atomic_set(&root->nr_swapfiles, 0);
 	root->log_transid = 0;
 	root->log_transid_committed = -1;
 	root->last_log_commit = 0;
@@ -2745,6 +2746,9 @@ int open_ctree(struct super_block *sb,
 	fs_info->sectorsize = 4096;
 	fs_info->stripesize = 4096;
 
+	spin_lock_init(&fs_info->swapfile_pins_lock);
+	fs_info->swapfile_pins = RB_ROOT;
+
 	ret = btrfs_alloc_stripe_hash_table(fs_info);
 	if (ret) {
 		err = ret;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 802a628e9f7d..36d8dcc7a475 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -290,6 +290,11 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 	} else if (fsflags & FS_COMPR_FL) {
 		const char *comp;
 
+		if (IS_SWAPFILE(inode)) {
+			ret = -ETXTBSY;
+			goto out_unlock;
+		}
+
 		binode->flags |= BTRFS_INODE_COMPRESS;
 		binode->flags &= ~BTRFS_INODE_NOCOMPRESS;
 
@@ -754,6 +759,12 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
 	if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
 		return -EINVAL;
 
+	if (atomic_read(&root->nr_swapfiles)) {
+		btrfs_warn(fs_info,
+			   "cannot snapshot subvolume with active swapfile");
+		return -ETXTBSY;
+	}
+
 	pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_KERNEL);
 	if (!pending_snapshot)
 		return -ENOMEM;
@@ -1505,9 +1516,13 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
 		}
 
 		inode_lock(inode);
-		if (do_compress)
-			BTRFS_I(inode)->defrag_compress = compress_type;
-		ret = cluster_pages_for_defrag(inode, pages, i, cluster);
+		if (IS_SWAPFILE(inode)) {
+			ret = -ETXTBSY;
+		} else {
+			if (do_compress)
+				BTRFS_I(inode)->defrag_compress = compress_type;
+			ret = cluster_pages_for_defrag(inode, pages, i, cluster);
+		}
 		if (ret < 0) {
 			inode_unlock(inode);
 			goto out_ra;
@@ -3577,6 +3592,11 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
 		goto out_unlock;
 	}
 
+	if (IS_SWAPFILE(src) || IS_SWAPFILE(dst)) {
+		ret = -ETXTBSY;
+		goto out_unlock;
+	}
+
 	tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
 	chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
 	if (chunk_count == 0)
@@ -4253,6 +4273,11 @@ static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
 		goto out_unlock;
 	}
 
+	if (IS_SWAPFILE(src) || IS_SWAPFILE(inode)) {
+		ret = -ETXTBSY;
+		goto out_unlock;
+	}
+
 	/* determine range to clone */
 	ret = -EINVAL;
 	if (off + len > src->i_size || off + len < off)
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index a3f75b8926d4..5471eea1c0fd 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4223,6 +4223,7 @@ static void describe_relocation(struct btrfs_fs_info *fs_info,
  */
 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
 {
+	struct btrfs_block_group_cache *bg;
 	struct btrfs_root *extent_root = fs_info->extent_root;
 	struct reloc_control *rc;
 	struct inode *inode;
@@ -4231,14 +4232,23 @@ int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
 	int rw = 0;
 	int err = 0;
 
+	bg = btrfs_lookup_block_group(fs_info, group_start);
+	if (!bg)
+		return -ENOENT;
+
+	if (btrfs_pinned_by_swapfile(fs_info, bg)) {
+		btrfs_put_block_group(bg);
+		return -ETXTBSY;
+	}
+
 	rc = alloc_reloc_control();
-	if (!rc)
+	if (!rc) {
+		btrfs_put_block_group(bg);
 		return -ENOMEM;
+	}
 
 	rc->extent_root = extent_root;
-
-	rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
-	BUG_ON(!rc->block_group);
+	rc->block_group = bg;
 
 	ret = btrfs_inc_block_group_ro(rc->block_group);
 	if (ret) {
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 303ae9de85b1..0f7925e34232 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1900,6 +1900,14 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path,
 		goto out;
 	}
 
+	if (btrfs_pinned_by_swapfile(fs_info, device)) {
+		btrfs_warn_in_rcu(fs_info,
+		  "cannot remove device %s (devid %llu) due to active swapfile",
+				  rcu_str_deref(device->name), device->devid);
+		ret = -ETXTBSY;
+		goto out;
+	}
+
 	if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
 		ret = BTRFS_ERROR_DEV_TGT_REPLACE;
 		goto out;
@@ -3638,10 +3646,15 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 
 		ret = btrfs_relocate_chunk(fs_info, found_key.offset);
 		mutex_unlock(&fs_info->delete_unused_bgs_mutex);
-		if (ret && ret != -ENOSPC)
-			goto error;
 		if (ret == -ENOSPC) {
 			enospc_errors++;
+		} else if (ret == -ETXTBSY) {
+			btrfs_info(fs_info,
+	   "skipping relocation of block group %llu due to active swapfile",
+				   found_key.offset);
+			ret = 0;
+		} else if (ret) {
+			goto error;
 		} else {
 			spin_lock(&fs_info->balance_lock);
 			bctl->stat.completed++;
@@ -4433,10 +4446,16 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 
 		ret = btrfs_relocate_chunk(fs_info, chunk_offset);
 		mutex_unlock(&fs_info->delete_unused_bgs_mutex);
-		if (ret && ret != -ENOSPC)
-			goto done;
-		if (ret == -ENOSPC)
+		if (ret == -ENOSPC) {
 			failed++;
+		} else if (ret) {
+			if (ret == -ETXTBSY) {
+				btrfs_warn(fs_info,
+		   "could not shrink block group %llu due to active swapfile",
+					   chunk_offset);
+			}
+			goto done;
+		}
 	} while (key.offset-- > 0);
 
 	if (failed && !retried) {
@@ -7572,3 +7591,27 @@ int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info)
 	btrfs_free_path(path);
 	return ret;
 }
+
+/*
+ * Check whether the given block group or device is pinned by any inode being
+ * used as a swapfile.
+ */
+bool btrfs_pinned_by_swapfile(struct btrfs_fs_info *fs_info, void *ptr)
+{
+	struct btrfs_swapfile_pin *sp;
+	struct rb_node *node;
+
+	spin_lock(&fs_info->swapfile_pins_lock);
+	node = fs_info->swapfile_pins.rb_node;
+	while (node) {
+		sp = rb_entry(node, struct btrfs_swapfile_pin, node);
+		if (ptr < sp->ptr)
+			node = node->rb_left;
+		else if (ptr > sp->ptr)
+			node = node->rb_right;
+		else
+			break;
+	}
+	spin_unlock(&fs_info->swapfile_pins_lock);
+	return node != NULL;
+}