From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Liu Subject: [PATCH] Btrfs: added new ioctl to set fs label Date: Thu, 01 Sep 2011 16:47:47 +0800 Message-ID: <4E5F46B3.50607@oracle.com> Reply-To: jeff.liu@oracle.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: chris.mason@oracle.com To: linux-btrfs@vger.kernel.org Return-path: List-ID: Hello, I'd like to introduce a new ioctl to set file system label. With this feature, we can execute `btrfs filesystem label [label] [path]` through btrfs tools to set or change the label. Signed-off-by: Jie Liu --- fs/btrfs/ctree.h | 6 ++++++ fs/btrfs/ioctl.c | 37 +++++++++++++++++++++++++++++++++++++ fs/btrfs/ioctl.h | 2 ++ 3 files changed, 45 insertions(+), 0 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 03912c5..2889b5e 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1259,6 +1259,12 @@ struct btrfs_ioctl_defrag_range_args { }; +struct btrfs_ioctl_fs_label_args { + /* label length in bytes */ + __u32 len; + char label[BTRFS_LABEL_SIZE]; +}; + /* * inode items have the data typically returned from stat and store other * info about object characteristics. There is one for every file and dir in diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 970977a..9e01628 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -268,6 +268,41 @@ static int btrfs_ioctl_getversion(struct file *file, int __user *arg) return put_user(inode->i_generation, arg); } +static int btrfs_ioctl_fs_setlabel(struct btrfs_root *root, void __user *arg) +{ + struct btrfs_super_block *super_block = &(root->fs_info->super_copy); + struct btrfs_ioctl_fs_label_args *label_args; + struct btrfs_trans_handle *trans; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (btrfs_root_readonly(root)) + return -EROFS; + + label_args = memdup_user(arg, sizeof(*label_args)); + if (IS_ERR(label_args)) + return PTR_ERR(label_args); + + if (label_args->len >= sizeof(label_args->label)) + return -EINVAL; + + mutex_lock(&root->fs_info->volume_mutex); + trans = btrfs_start_transaction(root, 0); + if (IS_ERR(trans)) + return PTR_ERR(trans); + + if (snprintf(super_block->label, BTRFS_LABEL_SIZE, "%s", + label_args->label) != label_args->len) + return -EFAULT; + + btrfs_end_transaction(trans, root); + mutex_unlock(&root->fs_info->volume_mutex); + + kfree(label_args); + return 0; +} + static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg) { struct btrfs_root *root = fdentry(file)->d_sb->s_fs_info; @@ -2876,6 +2911,8 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_fs_info(root, argp); case BTRFS_IOC_DEV_INFO: return btrfs_ioctl_dev_info(root, argp); + case BTRFS_IOC_FS_SETLABEL: + return btrfs_ioctl_fs_setlabel(root, argp); case BTRFS_IOC_BALANCE: return btrfs_balance(root->fs_info->dev_root); case BTRFS_IOC_CLONE: diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h index ad1ea78..1e0ca2a 100644 --- a/fs/btrfs/ioctl.h +++ b/fs/btrfs/ioctl.h @@ -248,4 +248,6 @@ struct btrfs_ioctl_space_args { struct btrfs_ioctl_dev_info_args) #define BTRFS_IOC_FS_INFO _IOR(BTRFS_IOCTL_MAGIC, 31, \ struct btrfs_ioctl_fs_info_args) +#define BTRFS_IOC_FS_SETLABEL _IOW(BTRFS_IOCTL_MAGIC, 32, \ + struct btrfs_ioctl_fs_label_args) #endif -- 1.7.4.1