From 49bac897683340457a0ab1f76b924a1220bdb604 Mon Sep 17 00:00:00 2001 From: Johannes Thumshirn Date: Mon, 13 Jul 2020 21:29:00 +0900 Subject: [PATCH] btrfs: add metadata_uuid to FS_INFO ioctl Add retrieval of the filesystem's metadata UUID to the fsinfo ioctl. This is driven by setting the BTRFS_FS_INFO_FLAG_METADATA_UUID flag in btrfs_ioctl_fs_info_args::flags. Reviewed-by: Nikolay Borisov Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ioctl.c | 6 ++++++ include/uapi/linux/btrfs.h | 5 ++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 55dd20d0f9cb..b4ddf51ae377 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3252,6 +3252,12 @@ static long btrfs_ioctl_fs_info(struct btrfs_fs_info *fs_info, fi_args->flags |= BTRFS_FS_INFO_FLAG_GENERATION; } + if (flags_in & BTRFS_FS_INFO_FLAG_METADATA_UUID) { + memcpy(&fi_args->metadata_uuid, fs_devices->metadata_uuid, + sizeof(fi_args->metadata_uuid)); + fi_args->flags |= BTRFS_FS_INFO_FLAG_METADATA_UUID; + } + if (copy_to_user(arg, fi_args, sizeof(*fi_args))) ret = -EFAULT; diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index 9b82e01c191d..2c39d15a2beb 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -252,6 +252,8 @@ struct btrfs_ioctl_dev_info_args { /* Request information about filesystem generation */ #define BTRFS_FS_INFO_FLAG_GENERATION (1 << 1) +/* Request information about filesystem metadata UUID */ +#define BTRFS_FS_INFO_FLAG_METADATA_UUID (1 << 2) struct btrfs_ioctl_fs_info_args { __u64 max_id; /* out */ @@ -265,7 +267,8 @@ struct btrfs_ioctl_fs_info_args { __u16 csum_size; /* out */ __u64 flags; /* in/out */ __u64 generation; /* out */ - __u8 reserved[960]; /* pad to 1k */ + __u8 metadata_uuid[BTRFS_FSID_SIZE]; /* out */ + __u8 reserved[944]; /* pad to 1k */ }; /*