diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 318be78..a67cc19 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1280,6 +1280,7 @@ struct btrfs_root {
 	int send_in_progress;
 	struct btrfs_subvolume_writers *subv_writers;
 	atomic_t will_be_snapshotted;
+	atomic_t snapshot_force_cow;
 
 	/* For qgroup metadata reserved space */
 	spinlock_t qgroup_meta_rsv_lock;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5124c15..05dc3c1 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1187,6 +1187,7 @@ static void __setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
 	atomic_set(&root->log_batch, 0);
 	refcount_set(&root->refs, 1);
 	atomic_set(&root->will_be_snapshotted, 0);
+	atomic_set(&root->snapshot_force_cow, 0);
 	root->log_transid = 0;
 	root->log_transid_committed = -1;
 	root->last_log_commit = 0;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3f51ddc..c6d8c5d 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1271,7 +1271,7 @@ static noinline int run_delalloc_nocow(struct inode *inode,
 	u64 disk_num_bytes;
 	u64 ram_bytes;
 	int extent_type;
-	int ret, err;
+	int ret;
 	int type;
 	int nocow;
 	int check_prev = 1;
@@ -1403,11 +1403,8 @@ static noinline int run_delalloc_nocow(struct inode *inode,
 			 * if there are pending snapshots for this root,
 			 * we fall into common COW way.
 			 */
-			if (!nolock) {
-				err = btrfs_start_write_no_snapshotting(root);
-				if (!err)
-					goto out_check;
-			}
+			if (!nolock && atomic_read(&root->snapshot_force_cow))
+				goto out_check;
 			/*
 			 * force cow if csum exists in the range.
 			 * this ensure that csum for a given extent are
@@ -1416,9 +1413,6 @@ static noinline int run_delalloc_nocow(struct inode *inode,
 			ret = csum_exist_in_range(fs_info, disk_bytenr,
 						  num_bytes);
 			if (ret) {
-				if (!nolock)
-					btrfs_end_write_no_snapshotting(root);
-
 				/*
 				 * ret could be -EIO if the above fails to read
 				 * metadata.
@@ -1431,11 +1425,8 @@ static noinline int run_delalloc_nocow(struct inode *inode,
 				WARN_ON_ONCE(nolock);
 				goto out_check;
 			}
-			if (!btrfs_inc_nocow_writers(fs_info, disk_bytenr)) {
-				if (!nolock)
-					btrfs_end_write_no_snapshotting(root);
+			if (!btrfs_inc_nocow_writers(fs_info, disk_bytenr))
 				goto out_check;
-			}
 			nocow = 1;
 		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 			extent_end = found_key.offset +
@@ -1448,8 +1439,6 @@ static noinline int run_delalloc_nocow(struct inode *inode,
 out_check:
 		if (extent_end <= start) {
 			path->slots[0]++;
-			if (!nolock && nocow)
-				btrfs_end_write_no_snapshotting(root);
 			if (nocow)
 				btrfs_dec_nocow_writers(fs_info, disk_bytenr);
 			goto next_slot;
@@ -1471,8 +1460,6 @@ static noinline int run_delalloc_nocow(struct inode *inode,
 					     end, page_started, nr_written, 1,
 					     NULL);
 			if (ret) {
-				if (!nolock && nocow)
-					btrfs_end_write_no_snapshotting(root);
 				if (nocow)
 					btrfs_dec_nocow_writers(fs_info,
 								disk_bytenr);
@@ -1492,8 +1479,6 @@ static noinline int run_delalloc_nocow(struct inode *inode,
 					  ram_bytes, BTRFS_COMPRESS_NONE,
 					  BTRFS_ORDERED_PREALLOC);
 			if (IS_ERR(em)) {
-				if (!nolock && nocow)
-					btrfs_end_write_no_snapshotting(root);
 				if (nocow)
 					btrfs_dec_nocow_writers(fs_info,
 								disk_bytenr);
@@ -1532,8 +1517,6 @@ static noinline int run_delalloc_nocow(struct inode *inode,
 					     EXTENT_CLEAR_DATA_RESV,
 					     PAGE_UNLOCK | PAGE_SET_PRIVATE2);
 
-		if (!nolock && nocow)
-			btrfs_end_write_no_snapshotting(root);
 		cur_offset = extent_end;
 
 		/*
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d3a5d2a..85c4284 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -747,6 +747,7 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
 	struct btrfs_pending_snapshot *pending_snapshot;
 	struct btrfs_trans_handle *trans;
 	int ret;
+	bool snapshot_force_cow = false;
 
 	if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
 		return -EINVAL;
@@ -763,6 +764,11 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
 		goto free_pending;
 	}
 
+	/*
+	 * Force new buffered writes to reserve space even when NOCOW is
+	 * possible. This is to avoid later writeback (running dealloc) to
+	 * fallback to COW mode and unexpectedly fail with ENOSPC.
+	 */
 	atomic_inc(&root->will_be_snapshotted);
 	smp_mb__after_atomic();
 	/* wait for no snapshot writes */
@@ -773,6 +779,14 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
 	if (ret)
 		goto dec_and_free;
 
+	/*
+	 * All previous writes have started writeback in NOCOW mode, so now
+	 * we force future writes to fallback to COW mode during snapshot
+	 * creation.
+	 */
+	atomic_inc(&root->snapshot_force_cow);
+	snapshot_force_cow = true;
+
 	btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1);
 
 	btrfs_init_block_rsv(&pending_snapshot->block_rsv,
@@ -837,6 +851,8 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
 fail:
 	btrfs_subvolume_release_metadata(fs_info, &pending_snapshot->block_rsv);
 dec_and_free:
+	if (snapshot_force_cow)
+		atomic_dec(&root->snapshot_force_cow);
 	if (atomic_dec_and_test(&root->will_be_snapshotted))
 		wake_up_var(&root->will_be_snapshotted);
 free_pending: