Hello, This patch set is trying to make Btrfs support get/set label for a mounted file sytem via ioctl(2). There are a couple of changes according to Miao's comments which were shown as following. Changes of V5->V4 in kernel: - Revise the ioctl number of BTRFS_IOC_GET_FSLABEL/BTRFS_IOC_SET_FSLABEL to 49/50 separately. - Replace btrfs_root_readonly() check up with mnt_want_write_file(). - Validate the input label length, return -EINVAL if the specified length is exceeding "BTRFS_LABEL_SIZE -1". Changes of V5->V4 in user space: - Revise the ioctl number accordingly. - Don't proceed to get/set the label upon a mounted file system if the dev patch is specified, i.e. btrfs filesystem label /dev/sdaX [new label] Instead, alert the user to execute this command against the mount point, i.e. btrfs filesystem label /btrfs_mount_path [new label] - Validate the input label length for changing the label upon an unmounted file system as well. We does not check it up currently, the command just keeping silent and truncate the label characters which are beyond "BTRFS_LABEL_SIZE - 1". Tests: ====== /dev/sda6 on /btrfs type btrfs (rw) jeff@koala:~/oss/btrfs-progs$ sudo ./btrfs filesystem label /btrfs btrfs_label Failure if the length is exceeding 255. jeff@koala:~/oss/btrfs-progs$ sudo ./btrfs filesystem label /btrfs `perl -e 'print "A"x256'` ERROR: unable to set label Invalid argument Otherwise, that's ok. jeff@koala:~/oss/btrfs-progs$ sudo ./btrfs filesystem label /btrfs `perl -e 'print "A"x255'` jeff@koala:~/oss/btrfs-progs$ sudo ./btrfs filesystem label /btrfs AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA The old versions can be found at: v4: http://permalink.gmane.org/gmane.comp.file-systems.btrfs/21618 v3: https://patchwork.kernel.org/patch/1124642/ v2: http://permalink.gmane.org/gmane.comp.file-systems.btrfs/12877 v1: http://permalink.gmane.org/gmane.comp.file-systems.btrfs/12872 Thanks, -Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
