hpfs: add fstrim support

This patch adds support for fstrim to the HPFS filesystem.

Signed-off-by: Mikulas Patocka <mikulas@twibright.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c
index 7cd00d3..037e3e5 100644
--- a/fs/hpfs/super.c
+++ b/fs/hpfs/super.c
@@ -196,6 +196,33 @@
 	return 0;
 }
 
+
+long hpfs_ioctl(struct file *file, unsigned cmd, unsigned long arg)
+{
+	switch (cmd) {
+		case FITRIM: {
+			struct fstrim_range range;
+			secno n_trimmed;
+			int r;
+			if (!capable(CAP_SYS_ADMIN))
+				return -EPERM;
+			if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range)))
+				return -EFAULT;
+			r = hpfs_trim_fs(file_inode(file)->i_sb, range.start >> 9, (range.start + range.len) >> 9, (range.minlen + 511) >> 9, &n_trimmed);
+			if (r)
+				return r;
+			range.len = (u64)n_trimmed << 9;
+			if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range)))
+				return -EFAULT;
+			return 0;
+		}
+		default: {
+			return -ENOIOCTLCMD;
+		}
+	}
+}
+
+
 static struct kmem_cache * hpfs_inode_cachep;
 
 static struct inode *hpfs_alloc_inode(struct super_block *sb)