Change the label of a mounted file system through the new ioctl BTRFS_IOCTL_FS_SETLABEL.
Signed-off-by: Jie Liu <jeff....@oracle.com> Signed-off-by: Anand Jain <anand.j...@oracle.com> --- btrfslabel.c | 84 ++++++++++++++++++++++++++++++++++------------------------ ioctl.h | 2 ++ 2 files changed, 51 insertions(+), 35 deletions(-) diff --git a/btrfslabel.c b/btrfslabel.c index 761a312..65388e5 100644 --- a/btrfslabel.c +++ b/btrfslabel.c @@ -46,25 +46,52 @@ #define GET_LABEL 3 #define SET_LABEL 4 -static void change_label_unmounted(char *dev, char *nLabel) +static int set_label_unmounted(const char *dev, const char *label) { - struct btrfs_root *root; - struct btrfs_trans_handle *trans; - - /* Open the super_block at the default location - * and as read-write. - */ - root = open_ctree(dev, 0, 1); - if (!root) /* errors are printed by open_ctree() */ - return; - - trans = btrfs_start_transaction(root, 1); - strncpy(root->fs_info->super_copy.label, nLabel, BTRFS_LABEL_SIZE); - root->fs_info->super_copy.label[BTRFS_LABEL_SIZE-1] = 0; - btrfs_commit_transaction(trans, root); - - /* Now we close it since we are done. */ - close_ctree(root); + struct btrfs_trans_handle *trans; + struct btrfs_root *root; + int ret; + + ret = check_mounted(dev); + if (ret < 0) { + fprintf(stderr, "FATAL: error checking %s mount status\n", dev); + return -1; + } + + /* Open the super_block at the default location + * and as read-write. + */ + root = open_ctree(dev, 0, 1); + if (!root) /* errors are printed by open_ctree() */ + return -1; + + trans = btrfs_start_transaction(root, 1); + strncpy(root->fs_info->super_copy.label, label, BTRFS_LABEL_SIZE); + root->fs_info->super_copy.label[BTRFS_LABEL_SIZE-1] = 0; + btrfs_commit_transaction(trans, root); + + /* Now we close it since we are done. */ + close_ctree(root); + return 0; +} + +static int set_label_mounted(const char *mount_path, const char *label) +{ + int fd; + + fd = open(mount_path, O_RDONLY | O_NOATIME); + if (fd < 0) { + fprintf(stderr, "ERROR: unable access to '%s'\n", mount_path); + return -1; + } + + if (ioctl(fd, BTRFS_IOC_SET_FSLABEL, label) < 0) { + fprintf(stderr, "ERROR: unable get label %s\n", strerror(errno)); + close(fd); + return -1; + } + + return 0; } static int get_label_unmounted(const char *dev) @@ -125,22 +152,9 @@ int get_label(const char *btrfs_dev) get_label_mounted(btrfs_dev); } -int set_label(char *btrfs_dev, char *nLabel) +int set_label(char *btrfs_dev, char *label) { - - int ret; - ret = check_mounted(btrfs_dev); - if (ret < 0) - { - fprintf(stderr, "FATAL: error checking %s mount status\n", btrfs_dev); - return -1; - } - - if(ret != 0) - { - fprintf(stderr, "FATAL: the filesystem has to be unmounted\n"); - return -2; - } - change_label_unmounted(btrfs_dev, nLabel); - return 0; + return is_existing_blk_or_reg_file(btrfs_dev) ? + set_label_unmounted(btrfs_dev, label) : + set_label_mounted(btrfs_dev, label); } diff --git a/ioctl.h b/ioctl.h index ed6784d..07259f9 100644 --- a/ioctl.h +++ b/ioctl.h @@ -434,4 +434,6 @@ struct btrfs_ioctl_clone_range_args { struct btrfs_ioctl_qgroup_limit_args) #define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 53, \ char[BTRFS_LABEL_SIZE]) +#define BTRFS_IOC_SET_FSLABEL _IOW(BTRFS_IOCTL_MAGIC, 54, \ + char[BTRFS_LABEL_SIZE]) #endif -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html