From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-bk0-f51.google.com ([209.85.214.51]:60381 "EHLO mail-bk0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756097Ab3AFSoZ (ORCPT ); Sun, 6 Jan 2013 13:44:25 -0500 Received: by mail-bk0-f51.google.com with SMTP id ik5so7951228bkc.24 for ; Sun, 06 Jan 2013 10:44:24 -0800 (PST) Message-ID: <50E9C617.7010303@gmail.com> Date: Sun, 06 Jan 2013 19:44:39 +0100 From: Goffredo Baroncelli Reply-To: kreijack@inwind.it MIME-Version: 1.0 To: Jeff Liu CC: linux-btrfs@vger.kernel.org, anand.jain@oracle.com, miaox@cn.fujitsu.com, dsterba@suse.cz Subject: Re: [RFC PATCH v9 1/2] Btrfs: Add a new ioctl to get the label of a mounted file system References: <50E79461.3090802@oracle.com> In-Reply-To: <50E79461.3090802@oracle.com> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi Jeff, On 01/05/2013 03:48 AM, Jeff Liu wrote: > Add a new ioctl(2) BTRFS_IOC_GET_FSLABLE, so that we can get the label upon a mounted filesystem. > > Signed-off-by: Jie Liu > Signed-off-by: Anand Jain > Cc: Miao Xie > Cc: Goffredo Baroncelli > Cc: David Sterba > > --- > fs/btrfs/ioctl.c | 21 +++++++++++++++++++++ > fs/btrfs/ioctl.h | 2 ++ > 2 files changed, 23 insertions(+) > > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index 8fcf9a5..ef2f55a 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -3699,6 +3699,25 @@ out: > return ret; > } > May be that it was already discussed, and I am missing something, but if we check the label length we should terminate the string with a zero in case this is too long... However this is a minor bug, please push this patch forward.. > +static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg) > +{ > + struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root; > + const char *label = root->fs_info->super_copy->label; > + size_t len = strnlen(label, BTRFS_LABEL_SIZE); > + int ret; + int label_is_too_long = 0; > + > + if (len == BTRFS_LABEL_SIZE) { > + pr_warn("btrfs: label is too long, return the first %zu bytes\n", > + --len); + label_is_too_long = 1; > + } > + > + mutex_lock(&root->fs_info->volume_mutex); > + ret = copy_to_user(arg, label, len); + if (!ret && label_is_too_long) + ret = copy_to_user(arg+BTRFS_LABEL_SIZE, "", 1); > + mutex_unlock(&root->fs_info->volume_mutex); > + > + return ret ? -EFAULT : 0; > +} > + > long btrfs_ioctl(struct file *file, unsigned int > cmd, unsigned long arg) > { > @@ -3797,6 +3816,8 @@ long btrfs_ioctl(struct file *file, unsigned int > return btrfs_ioctl_qgroup_create(root, argp); > case BTRFS_IOC_QGROUP_LIMIT: > return btrfs_ioctl_qgroup_limit(root, argp); > + case BTRFS_IOC_GET_FSLABEL: > + return btrfs_ioctl_get_fslabel(file, argp); > } > > return -ENOTTY; > diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h > index 731e287..5b2cbef 100644 > --- a/fs/btrfs/ioctl.h > +++ b/fs/btrfs/ioctl.h > @@ -451,6 +451,8 @@ struct btrfs_ioctl_send_args { > struct btrfs_ioctl_qgroup_create_args) > #define BTRFS_IOC_QGROUP_LIMIT _IOR(BTRFS_IOCTL_MAGIC, 43, \ > struct btrfs_ioctl_qgroup_limit_args) > +#define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 49, \ > + char[BTRFS_LABEL_SIZE]) > #define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \ > struct btrfs_ioctl_get_dev_stats) > #endif -- gpg @keyserver.linux.it: Goffredo Baroncelli (kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5