fs/ntfs3: implement NTFS3_IOC_SHUTDOWN ioctl

Add support for the NTFS3_IOC_SHUTDOWN ioctl, allowing userspace to
request a filesystem shutdown. The ioctl number is shared with other
filesystems such as ext4, exfat, and f2fs.

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index 60eb90bff9550658c1d123370268af6abd02da4d..b9484f48db34f8feb1983e9d812f2336b5ff7266 100644 (file)
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -19,6 +19,12 @@
 #include "ntfs.h"
 #include "ntfs_fs.h"
 
+/*
+ * cifx, btrfs, exfat, ext4, f2fs use this constant.
+ * Hope this value will become common to all fs.
+ */
+#define NTFS3_IOC_SHUTDOWN _IOR('X', 125, __u32)
+
 static int ntfs_ioctl_fitrim(struct ntfs_sb_info *sbi, unsigned long arg)
 {
        struct fstrim_range __user *user_range;
@@ -73,13 +79,47 @@ static int ntfs_ioctl_set_volume_label(struct ntfs_sb_info *sbi, u8 __user *buf)
        return ntfs_set_label(sbi, user, len);
 }
 
+/*
+ * ntfs_force_shutdown - helper function. Called from ioctl
+ */
+static int ntfs_force_shutdown(struct super_block *sb, u32 flags)
+{
+       int err;
+       struct ntfs_sb_info *sbi = sb->s_fs_info;
+
+       if (unlikely(ntfs3_forced_shutdown(sb)))
+               return 0;
+
+       /* No additional options yet (flags). */
+       err = bdev_freeze(sb->s_bdev);
+       if (err)
+               return err;
+       set_bit(NTFS_FLAGS_SHUTDOWN_BIT, &sbi->flags);
+       bdev_thaw(sb->s_bdev);
+       return 0;
+}
+
+static int ntfs_ioctl_shutdown(struct super_block *sb, unsigned long arg)
+{
+       u32 flags;
+
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
+
+       if (get_user(flags, (__u32 __user *)arg))
+               return -EFAULT;
+
+       return ntfs_force_shutdown(sb, flags);
+}
+
 /*
  * ntfs_ioctl - file_operations::unlocked_ioctl
  */
 long ntfs_ioctl(struct file *filp, u32 cmd, unsigned long arg)
 {
        struct inode *inode = file_inode(filp);
-       struct ntfs_sb_info *sbi = inode->i_sb->s_fs_info;
+       struct super_block *sb = inode->i_sb;
+       struct ntfs_sb_info *sbi = sb->s_fs_info;
 
        /* Avoid any operation if inode is bad. */
        if (unlikely(is_bad_ni(ntfs_i(inode))))
@@ -92,6 +132,8 @@ long ntfs_ioctl(struct file *filp, u32 cmd, unsigned long arg)
                return ntfs_ioctl_get_volume_label(sbi, (u8 __user *)arg);
        case FS_IOC_SETFSLABEL:
                return ntfs_ioctl_set_volume_label(sbi, (u8 __user *)arg);
+       case NTFS3_IOC_SHUTDOWN:
+               return ntfs_ioctl_shutdown(sb, arg);
        }
        return -ENOTTY; /* Inappropriate ioctl for device. */
 }