btrfs: send: enable support for stream v2 and compressed writes

Now that the new support is implemented, allow the ioctl to accept v2
and the compressed flag, and update the version in sysfs.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/send.c

@@ -701,8 +701,7 @@ static int send_header(struct send_ctx *sctx)
 	struct btrfs_stream_header hdr;
 
 	strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC);
-	hdr.version = cpu_to_le32(BTRFS_SEND_STREAM_VERSION);
-
+	hdr.version = cpu_to_le32(sctx->proto);
 	return write_buf(sctx->send_filp, &hdr, sizeof(hdr),
 					&sctx->send_off);
 }
@@ -7755,6 +7754,10 @@ long btrfs_ioctl_send(struct inode *inode, struct btrfs_ioctl_send_args *arg)
 	} else {
 		sctx->proto = 1;
 	}
+	if ((arg->flags & BTRFS_SEND_FLAG_COMPRESSED) && sctx->proto < 2) {
+		ret = -EINVAL;
+		goto out;
+	}
 
 	sctx->send_filp = fget(arg->send_fd);
 	if (!sctx->send_filp) {

fs/btrfs/send.h

@@ -10,7 +10,7 @@
 #include "ctree.h"
 
 #define BTRFS_SEND_STREAM_MAGIC "btrfs-stream"
-#define BTRFS_SEND_STREAM_VERSION 1
+#define BTRFS_SEND_STREAM_VERSION 2
 
 /*
  * In send stream v1, no command is larger than 64K. In send stream v2, no limit

include/uapi/linux/btrfs.h

@@ -788,7 +788,8 @@ struct btrfs_ioctl_received_subvol_args {
 	(BTRFS_SEND_FLAG_NO_FILE_DATA | \
 	 BTRFS_SEND_FLAG_OMIT_STREAM_HEADER | \
 	 BTRFS_SEND_FLAG_OMIT_END_CMD | \
-	 BTRFS_SEND_FLAG_VERSION)
+	 BTRFS_SEND_FLAG_VERSION | \
+	 BTRFS_SEND_FLAG_COMPRESSED)
 
 struct btrfs_ioctl_send_args {
 	__s64 send_fd;			/* in */