1 files changed, 56 insertions, 0 deletions

diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 698b85bb1dd4..3e50a4166283 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -20,6 +20,7 @@
 #include <linux/dirent.h>
 #include <linux/smp_lock.h>
 #include <linux/buffer_head.h>
+#include <linux/compat.h>
 #include <asm/uaccess.h>
 
 static inline loff_t fat_make_i_pos(struct super_block *sb,
@@ -741,10 +742,65 @@ static int fat_dir_ioctl(struct inode * inode, struct file * filp,
         return ret;
 }
 
+#ifdef CONFIG_COMPAT
+#define VFAT_IOCTL_READDIR_BOTH32       _IOR('r', 1, struct compat_dirent[2])
+#define VFAT_IOCTL_READDIR_SHORT32      _IOR('r', 2, struct compat_dirent[2])
+
+static long fat_compat_put_dirent32(struct dirent *d,
+                                    struct compat_dirent __user *d32)
+{
+        if (!access_ok(VERIFY_WRITE, d32, sizeof(struct compat_dirent)))
+                return -EFAULT;
+
+        __put_user(d->d_ino, &d32->d_ino);
+        __put_user(d->d_off, &d32->d_off);
+        __put_user(d->d_reclen, &d32->d_reclen);
+        if (__copy_to_user(d32->d_name, d->d_name, d->d_reclen))
+                return -EFAULT;
+
+        return 0;
+}
+
+static long fat_compat_dir_ioctl(struct file *file, unsigned cmd,
+                                 unsigned long arg)
+{
+        struct compat_dirent __user *p = compat_ptr(arg);
+        int ret;
+        mm_segment_t oldfs = get_fs();
+        struct dirent d[2];
+
+        switch (cmd) {
+        case VFAT_IOCTL_READDIR_BOTH32:
+                cmd = VFAT_IOCTL_READDIR_BOTH;
+                break;
+        case VFAT_IOCTL_READDIR_SHORT32:
+                cmd = VFAT_IOCTL_READDIR_SHORT;
+                break;
+        default:
+                return -ENOIOCTLCMD;
+        }
+
+        set_fs(KERNEL_DS);
+        lock_kernel();
+        ret = fat_dir_ioctl(file->f_dentry->d_inode, file,
+                            cmd, (unsigned long) &d);
+        unlock_kernel();
+        set_fs(oldfs);
+        if (ret >= 0) {
+                ret |= fat_compat_put_dirent32(&d[0], p);
+                ret |= fat_compat_put_dirent32(&d[1], p + 1);
+        }
+        return ret;
+}
+#endif /* CONFIG_COMPAT */
+
 const struct file_operations fat_dir_operations = {
         .read           = generic_read_dir,
         .readdir        = fat_readdir,
         .ioctl          = fat_dir_ioctl,
+#ifdef CONFIG_COMPAT
+        .compat_ioctl   = fat_compat_dir_ioctl,
+#endif
         .fsync          = file_fsync,
 };