[PATCH 1/4] btrfs-progs: get_fsid_fd() for getting fsid using fd

Goldwyn Rodrigues
2020-08-03T20:30:27Z

Add a function get_fsid_fd() to use an open file fd to get the
fsid of the mounted filesystem.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
common/utils.c | 30 ++++++++++++++++--------------
common/utils.h | 1 +
2 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/common/utils.c b/common/utils.c
index 9742c2e1..dbe1e806 100644
--- a/common/utils.c
+++ b/common/utils.c
@@ -1097,32 +1097,34 @@ out:
return ret;
}

+int get_fsid_fd(int fd, u8 *fsid)
+{
+ int ret;
+ struct btrfs_ioctl_fs_info_args args;
+
+ ret = ioctl(fd, BTRFS_IOC_FS_INFO, &args);
+ if (ret < 0)
+ return -errno;
+
+ memcpy(fsid, args.fsid, BTRFS_FSID_SIZE);
+ return 0;
+}
+
int get_fsid(const char *path, u8 *fsid, int silent)
{
int ret;
int fd;
- struct btrfs_ioctl_fs_info_args args;

fd = open(path, O_RDONLY);
if (fd < 0) {
- ret = -errno;
if (!silent)
error("failed to open %s: %m", path);
- goto out;
- }
-
- ret = ioctl(fd, BTRFS_IOC_FS_INFO, &args);
- if (ret < 0) {
- ret = -errno;
- goto out;
+ return -errno;
}

- memcpy(fsid, args.fsid, BTRFS_FSID_SIZE);
- ret = 0;
+ ret = get_fsid_fd(fd, fsid);
+ close(fd);

-out:
- if (fd != -1)
- close(fd);
return ret;
}

diff --git a/common/utils.h b/common/utils.h
index 43e7f471..e34bb5a4 100644
--- a/common/utils.h
+++ b/common/utils.h
@@ -75,6 +75,7 @@ void close_file_or_dir(int fd, DIR *dirstream);
int get_fs_info(const char *path, struct btrfs_ioctl_fs_info_args *fi_args,
struct btrfs_ioctl_dev_info_args **di_ret);
int get_fsid(const char *path, u8 *fsid, int silent);
+int get_fsid_fd(int fd, u8 *fsid);

int get_label(const char *btrfs_dev, char *label);
int set_label(const char *btrfs_dev, const char *label);
--
2.26.2