f2fs: avoid to write during the recovery

This patch enhances the recovery routine not to write any data/node/meta until
its completion.
If any writes are sent to the disk, it could contaminate the written history
that will be used for further recovery.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/checkpoint.c

@@ -81,7 +81,7 @@ static int f2fs_write_meta_page(struct page *page,
 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 
 	/* Should not write any meta pages, if any IO error was occurred */
-	if (wbc->for_reclaim ||
+	if (wbc->for_reclaim || sbi->por_doing ||
 			is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)) {
 		dec_page_count(sbi, F2FS_DIRTY_META);
 		wbc->pages_skipped++;

fs/f2fs/node.c

@@ -1156,6 +1156,9 @@ static int f2fs_write_node_page(struct page *page,
 	block_t new_addr;
 	struct node_info ni;
 
+	if (sbi->por_doing)
+		goto redirty_out;
+
 	wait_on_page_writeback(page);
 
 	/* get old block addr of this node page */
@@ -1171,12 +1174,8 @@ static int f2fs_write_node_page(struct page *page,
 		return 0;
 	}
 
-	if (wbc->for_reclaim) {
-		dec_page_count(sbi, F2FS_DIRTY_NODES);
-		wbc->pages_skipped++;
-		set_page_dirty(page);
-		return AOP_WRITEPAGE_ACTIVATE;
-	}
+	if (wbc->for_reclaim)
+		goto redirty_out;
 
 	mutex_lock(&sbi->node_write);
 	set_page_writeback(page);
@@ -1186,6 +1185,12 @@ static int f2fs_write_node_page(struct page *page,
 	mutex_unlock(&sbi->node_write);
 	unlock_page(page);
 	return 0;
+
+redirty_out:
+	dec_page_count(sbi, F2FS_DIRTY_NODES);
+	wbc->pages_skipped++;
+	set_page_dirty(page);
+	return AOP_WRITEPAGE_ACTIVATE;
 }
 
 /*