[PATCH] reiserfs: reiserfs: check for files > 2GB on 3.5.x disks

When a filesystem has been converted from 3.5.x to 3.6.x, we need an extra
check during file write to make sure we are not trying to make a 3.5.x file
> 2GB.
Signed-off-by: NChris Mason <mason@suse.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

fs/reiserfs/file.c

@@ -1287,6 +1287,23 @@ static ssize_t reiserfs_file_write(struct file *file,	/* the file we are going t
 	struct reiserfs_transaction_handle th;
 	th.t_trans_id = 0;
 
+	/* If a filesystem is converted from 3.5 to 3.6, we'll have v3.5 items
+	* lying around (most of the disk, in fact). Despite the filesystem
+	* now being a v3.6 format, the old items still can't support large
+	* file sizes. Catch this case here, as the rest of the VFS layer is
+	* oblivious to the different limitations between old and new items.
+	* reiserfs_setattr catches this for truncates. This chunk is lifted
+	* from generic_write_checks. */
+	if (get_inode_item_key_version (inode) == KEY_FORMAT_3_5 &&
+	    *ppos + count > MAX_NON_LFS) {
+		if (*ppos >= MAX_NON_LFS) {
+			send_sig(SIGXFSZ, current, 0);
+			return -EFBIG;
+		}
+		if (count > MAX_NON_LFS - (unsigned long)*ppos)
+			count = MAX_NON_LFS - (unsigned long)*ppos;
+	}
+
 	if (file->f_flags & O_DIRECT) {	// Direct IO needs treatment
 		ssize_t result, after_file_end = 0;
 		if ((*ppos + count >= inode->i_size)