nilfs2: add support for FS_IOC_SETFSLABEL

Implement support for FS_IOC_SETFSLABEL ioctl to write filesystem label.

Link: https://lkml.kernel.org/r/20240815074408.5550-5-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index b5c6a50d6d5dc103b999077741693646461cb8b3..297989e51ee6e64e853c248efa0f550d2e37b079 100644 (file)
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -1290,6 +1290,68 @@ static int nilfs_ioctl_get_fslabel(struct super_block *sb, void __user *argp)
        return 0;
 }
 
+/**
+ * nilfs_ioctl_set_fslabel - set the volume name of the file system
+ * @sb:   super block instance
+ * @filp: file object
+ * @argp: pointer to userspace memory that contains the volume name
+ *
+ * Return: 0 on success, or the following negative error code on failure.
+ * * %-EFAULT  - Error copying input data.
+ * * %-EINVAL  - Label length exceeds record size in superblock.
+ * * %-EIO     - I/O error.
+ * * %-EPERM   - Operation not permitted (insufficient permissions).
+ * * %-EROFS   - Read only file system.
+ */
+static int nilfs_ioctl_set_fslabel(struct super_block *sb, struct file *filp,
+                                  void __user *argp)
+{
+       char label[NILFS_MAX_VOLUME_NAME + 1];
+       struct the_nilfs *nilfs = sb->s_fs_info;
+       struct nilfs_super_block **sbp;
+       size_t len;
+       int ret;
+
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
+
+       ret = mnt_want_write_file(filp);
+       if (ret)
+               return ret;
+
+       if (copy_from_user(label, argp, NILFS_MAX_VOLUME_NAME + 1)) {
+               ret = -EFAULT;
+               goto out_drop_write;
+       }
+
+       len = strnlen(label, NILFS_MAX_VOLUME_NAME + 1);
+       if (len > NILFS_MAX_VOLUME_NAME) {
+               nilfs_err(sb, "unable to set label with more than %zu bytes",
+                         NILFS_MAX_VOLUME_NAME);
+               ret = -EINVAL;
+               goto out_drop_write;
+       }
+
+       down_write(&nilfs->ns_sem);
+       sbp = nilfs_prepare_super(sb, false);
+       if (unlikely(!sbp)) {
+               ret = -EIO;
+               goto out_unlock;
+       }
+
+       strtomem_pad(sbp[0]->s_volume_name, label, 0);
+       if (sbp[1])
+               strtomem_pad(sbp[1]->s_volume_name, label, 0);
+
+       ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
+
+out_unlock:
+       up_write(&nilfs->ns_sem);
+out_drop_write:
+       mnt_drop_write_file(filp);
+       return ret;
+}
+
 long nilfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
        struct inode *inode = file_inode(filp);
@@ -1334,6 +1396,8 @@ long nilfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                return nilfs_ioctl_trim_fs(inode, argp);
        case FS_IOC_GETFSLABEL:
                return nilfs_ioctl_get_fslabel(inode->i_sb, argp);
+       case FS_IOC_SETFSLABEL:
+               return nilfs_ioctl_set_fslabel(inode->i_sb, filp, argp);
        default:
                return -ENOTTY;
        }
@@ -1361,6 +1425,7 @@ long nilfs_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
        case NILFS_IOCTL_SET_ALLOC_RANGE:
        case FITRIM:
        case FS_IOC_GETFSLABEL:
+       case FS_IOC_SETFSLABEL:
                break;
        default:
                return -ENOIOCTLCMD;