fs/ntfs3: grow log scratch buffer for page size changes

The linux-next fix starts log replay with DefaultLogPageSize so 64K kernels can mount smaller NTFS volumes. log_replay() may later adopt an on-disk sys_page_size/page_size that is larger than the initial 4K value.

one_page_buf is allocated before that adjustment, and read_log_page() uses it for unaligned page reads sized by log->page_size. Grow one_page_buf before assigning a larger validated page size so later reads have a scratch buffer large enough for the adopted log page size.

Change-Id: I4a1491fa96b2d6b810278f58160ed070900b2ad5
Signed-off-by: Jamie Nguyen <jamien@nvidia.com>

Author: test

fs/ntfs3/fslog.c

@@ -3924,13 +3924,32 @@ int log_replay(struct ntfs_inode *ni, bool *initialized)
 	 */
 	t32 = le32_to_cpu(log->rst_info.r_page->sys_page_size);
 	if (log->page_size != t32) {
+		u32 new_page_size;
+
 		log->l_size = log->orig_file_size;
-		log->page_size = norm_file_page(t32, &log->l_size,
-						t32 == DefaultLogPageSize);
+		new_page_size = norm_file_page(t32, &log->l_size,
+					       t32 == DefaultLogPageSize);
+		if (new_page_size != t32) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		if (new_page_size > log->page_size) {
+			void *one_page_buf;
+
+			one_page_buf = krealloc(log->one_page_buf, new_page_size,
+						GFP_NOFS);
+			if (!one_page_buf) {
+				err = -ENOMEM;
+				goto out;
+			}
+			log->one_page_buf = one_page_buf;
+		}
+
+		log->page_size = new_page_size;
 	}
 
-	if (log->page_size != t32 ||
-	    log->page_size != le32_to_cpu(log->rst_info.r_page->page_size)) {
+	if (log->page_size != le32_to_cpu(log->rst_info.r_page->page_size)) {
 		err = -EINVAL;
 		goto out;
 	}