bcachefs: support FS_IOC_SETFSLABEL

Implement support for FS_IOC_SETFSLABEL ioctl to set filesystem
label.

Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/fs-ioctl.c b/fs/bcachefs/fs-ioctl.c
index c82c25e7f45ae55ee75b7a57eed29a6477a68145..aea8132d2c40e585eabd923a9138035f87827455 100644 (file)
--- a/fs/bcachefs/fs-ioctl.c
+++ b/fs/bcachefs/fs-ioctl.c
@@ -301,6 +301,41 @@ static int bch2_ioc_getlabel(struct bch_fs *c, char __user *user_label)
        return ret ? -EFAULT : 0;
 }
 
+static int bch2_ioc_setlabel(struct bch_fs *c,
+                            struct file *file,
+                            struct bch_inode_info *inode,
+                            const char __user *user_label)
+{
+       int ret;
+       char label[BCH_SB_LABEL_SIZE];
+
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
+
+       if (copy_from_user(label, user_label, sizeof(label)))
+               return -EFAULT;
+
+       if (strnlen(label, BCH_SB_LABEL_SIZE) == BCH_SB_LABEL_SIZE) {
+               bch_err(c,
+                       "unable to set label with more than %d bytes",
+                       BCH_SB_LABEL_SIZE - 1);
+               return -EINVAL;
+       }
+
+       ret = mnt_want_write_file(file);
+       if (ret)
+               return ret;
+
+       mutex_lock(&c->sb_lock);
+       strscpy(c->disk_sb.sb->label, label, BCH_SB_LABEL_SIZE);
+       mutex_unlock(&c->sb_lock);
+
+       ret = bch2_write_super(c);
+
+       mnt_drop_write_file(file);
+       return ret;
+}
+
 static int bch2_ioc_goingdown(struct bch_fs *c, u32 __user *arg)
 {
        u32 flags;
@@ -539,6 +574,10 @@ long bch2_fs_file_ioctl(struct file *file, unsigned cmd, unsigned long arg)
                ret = bch2_ioc_getlabel(c, (void __user *) arg);
                break;
 
+       case FS_IOC_SETFSLABEL:
+               ret = bch2_ioc_setlabel(c, file, inode, (const void __user *) arg);
+               break;
+
        case FS_IOC_GOINGDOWN:
                ret = bch2_ioc_goingdown(c, (u32 __user *) arg);
                break;
@@ -584,6 +623,7 @@ long bch2_compat_fs_ioctl(struct file *file, unsigned cmd, unsigned long arg)
                cmd = FS_IOC_GETVERSION;
                break;
        case FS_IOC_GETFSLABEL:
+       case FS_IOC_SETFSLABEL:
                break;
        default:
                return -ENOIOCTLCMD;