From e77fbf990316d47968a793d8aa920fd62385aec9 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 22 Oct 2021 16:53:36 +0200 Subject: btrfs: send: prepare for v2 protocol This is preparatory work for send protocol update to version 2 and higher. We have many pending protocol update requests but still don't have the basic protocol rev in place, the first thing that must happen is to do the actual versioning support. The protocol version is u32 and is a new member in the send ioctl struct. Validity of the version field is backed by a new flag bit. Old kernels would fail when a higher version is requested. Version protocol 0 will pick the highest supported version, BTRFS_SEND_STREAM_VERSION, that's also exported in sysfs. The version is still unchanged and will be increased once we have new incompatible commands or stream updates. Reviewed-by: Nikolay Borisov Signed-off-by: David Sterba --- include/uapi/linux/btrfs.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index d7d3cfead056..738619994e26 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -771,10 +771,16 @@ struct btrfs_ioctl_received_subvol_args { */ #define BTRFS_SEND_FLAG_OMIT_END_CMD 0x4 +/* + * Read the protocol version in the structure + */ +#define BTRFS_SEND_FLAG_VERSION 0x8 + #define BTRFS_SEND_FLAG_MASK \ (BTRFS_SEND_FLAG_NO_FILE_DATA | \ BTRFS_SEND_FLAG_OMIT_STREAM_HEADER | \ - BTRFS_SEND_FLAG_OMIT_END_CMD) + BTRFS_SEND_FLAG_OMIT_END_CMD | \ + BTRFS_SEND_FLAG_VERSION) struct btrfs_ioctl_send_args { __s64 send_fd; /* in */ @@ -782,7 +788,8 @@ struct btrfs_ioctl_send_args { __u64 __user *clone_sources; /* in */ __u64 parent_root; /* in */ __u64 flags; /* in */ - __u64 reserved[4]; /* in */ + __u32 version; /* in */ + __u8 reserved[28]; /* in */ }; /* -- cgit v1.2.3