| Message ID | 50E79468.7050407@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Reviewed-by: Goffredo Baroncelli <kreijack@inwind.it> On 01/05/2013 03:48 AM, Jeff Liu wrote: > With this new ioctl(2) BTRFS_IOC_SET_FSLABEL, we can set/change the label of a mounted file system. > > Signed-off-by: Jie Liu <jeff.liu@oracle.com> > Signed-off-by: Anand Jain <anand.jain@oracle.com> > Reviewed-by: Miao Xie <miaox@cn.fujitsu.com> > Reviewed-by: Goffredo Baroncelli <kreijack@inwind.it> > Reviewed-by: David Sterba <dsterba@suse.cz> > > --- > fs/btrfs/ioctl.c | 42 ++++++++++++++++++++++++++++++++++++++++++ > fs/btrfs/ioctl.h | 2 ++ > 2 files changed, 44 insertions(+) > > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index ef2f55a..8e676c3 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -3718,6 +3718,46 @@ static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg) > return ret ? -EFAULT : 0; > } > > +static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg) > +{ > + struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root; > + struct btrfs_super_block *super_block = root->fs_info->super_copy; > + struct btrfs_trans_handle *trans; > + char label[BTRFS_LABEL_SIZE]; > + int ret; > + > + if (!capable(CAP_SYS_ADMIN)) > + return -EPERM; > + > + if (copy_from_user(label, arg, sizeof(label))) > + return -EFAULT; > + > + if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) { > + pr_err("btrfs: unable to set label with more than %d bytes\n", > + BTRFS_LABEL_SIZE - 1); > + return -EINVAL; > + } > + > + ret = mnt_want_write_file(file); > + if (ret) > + return ret; > + > + mutex_lock(&root->fs_info->volume_mutex); > + trans = btrfs_start_transaction(root, 0); > + if (IS_ERR(trans)) { > + ret = PTR_ERR(trans); > + goto out_unlock; > + } > + > + strcpy(super_block->label, label); > + ret = btrfs_end_transaction(trans, root); > + > +out_unlock: > + mutex_unlock(&root->fs_info->volume_mutex); > + mnt_drop_write_file(file); > + return ret; > +} > + > long btrfs_ioctl(struct file *file, unsigned int > cmd, unsigned long arg) > { > @@ -3818,6 +3858,8 @@ long btrfs_ioctl(struct file *file, unsigned int > return btrfs_ioctl_qgroup_limit(root, argp); > case BTRFS_IOC_GET_FSLABEL: > return btrfs_ioctl_get_fslabel(file, argp); > + case BTRFS_IOC_SET_FSLABEL: > + return btrfs_ioctl_set_fslabel(file, argp); > } > > return -ENOTTY; > diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h > index 5b2cbef..2abe239 100644 > --- a/fs/btrfs/ioctl.h > +++ b/fs/btrfs/ioctl.h > @@ -453,6 +453,8 @@ struct btrfs_ioctl_send_args { > struct btrfs_ioctl_qgroup_limit_args) > #define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 49, \ > char[BTRFS_LABEL_SIZE]) > +#define BTRFS_IOC_SET_FSLABEL _IOW(BTRFS_IOCTL_MAGIC, 50, \ > + char[BTRFS_LABEL_SIZE]) > #define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \ > struct btrfs_ioctl_get_dev_stats) > #endif
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index ef2f55a..8e676c3 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3718,6 +3718,46 @@ static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg) return ret ? -EFAULT : 0; } +static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg) +{ + struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root; + struct btrfs_super_block *super_block = root->fs_info->super_copy; + struct btrfs_trans_handle *trans; + char label[BTRFS_LABEL_SIZE]; + int ret; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (copy_from_user(label, arg, sizeof(label))) + return -EFAULT; + + if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) { + pr_err("btrfs: unable to set label with more than %d bytes\n", + BTRFS_LABEL_SIZE - 1); + return -EINVAL; + } + + ret = mnt_want_write_file(file); + if (ret) + return ret; + + mutex_lock(&root->fs_info->volume_mutex); + trans = btrfs_start_transaction(root, 0); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + goto out_unlock; + } + + strcpy(super_block->label, label); + ret = btrfs_end_transaction(trans, root); + +out_unlock: + mutex_unlock(&root->fs_info->volume_mutex); + mnt_drop_write_file(file); + return ret; +} + long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -3818,6 +3858,8 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_qgroup_limit(root, argp); case BTRFS_IOC_GET_FSLABEL: return btrfs_ioctl_get_fslabel(file, argp); + case BTRFS_IOC_SET_FSLABEL: + return btrfs_ioctl_set_fslabel(file, argp); } return -ENOTTY; diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h index 5b2cbef..2abe239 100644 --- a/fs/btrfs/ioctl.h +++ b/fs/btrfs/ioctl.h @@ -453,6 +453,8 @@ struct btrfs_ioctl_send_args { struct btrfs_ioctl_qgroup_limit_args) #define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 49, \ char[BTRFS_LABEL_SIZE]) +#define BTRFS_IOC_SET_FSLABEL _IOW(BTRFS_IOCTL_MAGIC, 50, \ + char[BTRFS_LABEL_SIZE]) #define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \ struct btrfs_ioctl_get_dev_stats) #endif