Revert: "f2fs: check last page index in cached bio to decide submission"

There is one case that we can leave bio in f2fs, result in hanging
page writeback waiter.

Thread A				Thread B
- f2fs_write_cache_pages
 - f2fs_submit_page_write
 page #0 cached in bio #0 of cold log
 - f2fs_submit_page_write
 page #1 cached in bio #1 of warm log
					- f2fs_write_cache_pages
					 - f2fs_submit_page_write
					 bio is full, submit bio #1 contain page #1
 - f2fs_submit_merged_write_cond(, page #1)
 fail to submit bio #0 due to page #1 is not in any cached bios.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -322,8 +322,8 @@ static void __submit_merged_bio(struct f2fs_bio_info *io)
 	io->bio = NULL;
 }
 
-static bool __has_merged_page(struct f2fs_bio_info *io,
-				struct inode *inode, nid_t ino, pgoff_t idx)
+static bool __has_merged_page(struct f2fs_bio_info *io, struct inode *inode,
+						struct page *page, nid_t ino)
 {
 	struct bio_vec *bvec;
 	struct page *target;
@@ -332,7 +332,7 @@ static bool __has_merged_page(struct f2fs_bio_info *io,
 	if (!io->bio)
 		return false;
 
-	if (!inode && !ino)
+	if (!inode && !page && !ino)
 		return true;
 
 	bio_for_each_segment_all(bvec, io->bio, i) {
@@ -342,11 +342,10 @@ static bool __has_merged_page(struct f2fs_bio_info *io,
 		else
 			target = fscrypt_control_page(bvec->bv_page);
 
-		if (idx != target->index)
-			continue;
-
 		if (inode && inode == target->mapping->host)
 			return true;
+		if (page && page == target)
+			return true;
 		if (ino && ino == ino_of_node(target))
 			return true;
 	}
@@ -355,7 +354,8 @@ static bool __has_merged_page(struct f2fs_bio_info *io,
 }
 
 static bool has_merged_page(struct f2fs_sb_info *sbi, struct inode *inode,
-				nid_t ino, pgoff_t idx, enum page_type type)
+						struct page *page, nid_t ino,
+						enum page_type type)
 {
 	enum page_type btype = PAGE_TYPE_OF_BIO(type);
 	enum temp_type temp;
@@ -366,7 +366,7 @@ static bool has_merged_page(struct f2fs_sb_info *sbi, struct inode *inode,
 		io = sbi->write_io[btype] + temp;
 
 		down_read(&io->io_rwsem);
-		ret = __has_merged_page(io, inode, ino, idx);
+		ret = __has_merged_page(io, inode, page, ino);
 		up_read(&io->io_rwsem);
 
 		/* TODO: use HOT temp only for meta pages now. */
@@ -397,12 +397,12 @@ static void __f2fs_submit_merged_write(struct f2fs_sb_info *sbi,
 }
 
 static void __submit_merged_write_cond(struct f2fs_sb_info *sbi,
-				struct inode *inode, nid_t ino, pgoff_t idx,
-				enum page_type type, bool force)
+				struct inode *inode, struct page *page,
+				nid_t ino, enum page_type type, bool force)
 {
 	enum temp_type temp;
 
-	if (!force && !has_merged_page(sbi, inode, ino, idx, type))
+	if (!force && !has_merged_page(sbi, inode, page, ino, type))
 		return;
 
 	for (temp = HOT; temp < NR_TEMP_TYPE; temp++) {
@@ -421,10 +421,10 @@ void f2fs_submit_merged_write(struct f2fs_sb_info *sbi, enum page_type type)
 }
 
 void f2fs_submit_merged_write_cond(struct f2fs_sb_info *sbi,
-				struct inode *inode, nid_t ino, pgoff_t idx,
-				enum page_type type)
+				struct inode *inode, struct page *page,
+				nid_t ino, enum page_type type)
 {
-	__submit_merged_write_cond(sbi, inode, ino, idx, type, false);
+	__submit_merged_write_cond(sbi, inode, page, ino, type, false);
 }
 
 void f2fs_flush_merged_writes(struct f2fs_sb_info *sbi)
@@ -1952,7 +1952,7 @@ out:
 		ClearPageUptodate(page);
 
 	if (wbc->for_reclaim) {
-		f2fs_submit_merged_write_cond(sbi, inode, 0, page->index, DATA);
+		f2fs_submit_merged_write_cond(sbi, NULL, page, 0, DATA);
 		clear_inode_flag(inode, FI_HOT_DATA);
 		f2fs_remove_dirty_inode(inode);
 		submitted = NULL;
@@ -2010,10 +2010,10 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 	pgoff_t index;
 	pgoff_t end;		/* Inclusive */
 	pgoff_t done_index;
-	pgoff_t last_idx = ULONG_MAX;
 	int cycled;
 	int range_whole = 0;
 	int tag;
+	int nwritten = 0;
 
 	pagevec_init(&pvec);
 
@@ -2116,7 +2116,7 @@ continue_unlock:
 				done = 1;
 				break;
 			} else if (submitted) {
-				last_idx = page->index;
+				nwritten++;
 			}
 
 			if (--wbc->nr_to_write <= 0 &&
@@ -2138,9 +2138,9 @@ continue_unlock:
 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 		mapping->writeback_index = done_index;
 
-	if (last_idx != ULONG_MAX)
+	if (nwritten)
 		f2fs_submit_merged_write_cond(F2FS_M_SB(mapping), mapping->host,
-						0, last_idx, DATA);
+								NULL, 0, DATA);
 
 	return ret;
 }