f2fs: move grabing orphan pages out of protection region

Move grabing orphan block page out of protection region, and grab all
the orphan block pages ahead.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: remove unnecessary code pointed by Chao Yu]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/checkpoint.c

@@ -303,22 +303,25 @@ static void write_orphan_inodes(struct f2fs_sb_info *sbi, block_t start_blk)
 {
 	struct list_head *head;
 	struct f2fs_orphan_block *orphan_blk = NULL;
-	struct page *page = NULL;
 	unsigned int nentries = 0;
-	unsigned short index = 1;
-	unsigned short orphan_blocks;
+	unsigned short index;
+	unsigned short orphan_blocks = (unsigned short)((sbi->n_orphans +
+		(F2FS_ORPHANS_PER_BLOCK - 1)) / F2FS_ORPHANS_PER_BLOCK);
+	struct page *page = NULL;
+	struct page *pages[orphan_blocks];
 	struct orphan_inode_entry *orphan = NULL;
 
-	orphan_blocks = (unsigned short)((sbi->n_orphans +
-		(F2FS_ORPHANS_PER_BLOCK - 1)) / F2FS_ORPHANS_PER_BLOCK);
+	for (index = 0; index < orphan_blocks; index++)
+		pages[index] = grab_meta_page(sbi, start_blk + index);
 
+	index = 1;
 	mutex_lock(&sbi->orphan_inode_mutex);
 	head = &sbi->orphan_inode_list;
 
 	/* loop for each orphan inode entry and write them in Jornal block */
 	list_for_each_entry(orphan, head, list) {
 		if (!page) {
-			page = grab_meta_page(sbi, start_blk);
+			page = pages[index - 1];
 			orphan_blk =
 				(struct f2fs_orphan_block *)page_address(page);
 			memset(orphan_blk, 0, sizeof(*orphan_blk));
@@ -338,7 +341,6 @@ static void write_orphan_inodes(struct f2fs_sb_info *sbi, block_t start_blk)
 			set_page_dirty(page);
 			f2fs_put_page(page, 1);
 			index++;
-			start_blk++;
 			nentries = 0;
 			page = NULL;
 		}