[RFC PATCH] f2fs: Convert f2fs_write_cache_pages() to use filemap_get_folios_tag()

["Vishal Moola (Oracle)" <vishal.moola@gmail.com>]

Converted the function to use a folio_batch instead of pagevec. This is in
preparation for the removal of find_get_pages_range_tag().

Also modified f2fs_all_cluster_page_ready to take in a folio_batch instead
of pagevec. This does NOT support large folios. The function currently
only utilizes folios of size 1 so this shouldn't cause any issues right
now.

This version of the patch limits the number of pages fetched to
F2FS_ONSTACK_PAGES. If that ever happens, update the start index here
since filemap_get_folios_tag() updates the index to be after the last
found folio, not necessarily the last used page.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
---

Let me know if you prefer this version and I'll include it in v5
of the patch series when I rebase it after the merge window.

---
 fs/f2fs/data.c | 86 ++++++++++++++++++++++++++++++++++----------------
 1 file changed, 59 insertions(+), 27 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index a71e818cd67b..1703e353f0e0 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2939,6 +2939,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 	int ret = 0;
 	int done = 0, retry = 0;
 	struct page *pages[F2FS_ONSTACK_PAGES];
+	struct folio_batch fbatch;
 	struct f2fs_sb_info *sbi = F2FS_M_SB(mapping);
 	struct bio *bio = NULL;
 	sector_t last_block;
@@ -2959,6 +2960,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 		.private = NULL,
 	};
 #endif
+	int nr_folios, p, idx;
 	int nr_pages;
 	pgoff_t index;
 	pgoff_t end;		/* Inclusive */
@@ -2969,6 +2971,8 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 	int submitted = 0;
 	int i;
 
+	folio_batch_init(&fbatch);
+
 	if (get_dirty_pages(mapping->host) <=
 				SM_I(F2FS_M_SB(mapping))->min_hot_blocks)
 		set_inode_flag(mapping->host, FI_HOT_DATA);
@@ -2994,13 +2998,38 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 		tag_pages_for_writeback(mapping, index, end);
 	done_index = index;
 	while (!done && !retry && (index <= end)) {
-		nr_pages = find_get_pages_range_tag(mapping, &index, end,
-				tag, F2FS_ONSTACK_PAGES, pages);
-		if (nr_pages == 0)
+		nr_pages = 0;
+again:
+		nr_folios = filemap_get_folios_tag(mapping, &index, end,
+				tag, &fbatch);
+		if (nr_folios == 0) {
+			if (nr_pages)
+				goto write;
 			break;
+		}
 
+		for (i = 0; i < nr_folios; i++) {
+			struct folio* folio = fbatch.folios[i];
+
+			idx = 0;
+			p = folio_nr_pages(folio);
+add_more:
+			pages[nr_pages] = folio_page(folio,idx);
+			folio_ref_inc(folio);
+			if (++nr_pages == F2FS_ONSTACK_PAGES) {
+				index = folio->index + idx + 1;
+				folio_batch_release(&fbatch);
+				goto write;
+			}
+			if (++idx < p)
+				goto add_more;
+		}
+		folio_batch_release(&fbatch);
+		goto again;
+write:
 		for (i = 0; i < nr_pages; i++) {
 			struct page *page = pages[i];
+			struct folio *folio = page_folio(page);
 			bool need_readd;
 readd:
 			need_readd = false;
@@ -3017,7 +3046,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 				}
 
 				if (!f2fs_cluster_can_merge_page(&cc,
-								page->index)) {
+								folio->index)) {
 					ret = f2fs_write_multi_pages(&cc,
 						&submitted, wbc, io_type);
 					if (!ret)
@@ -3026,27 +3055,28 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 				}
 
 				if (unlikely(f2fs_cp_error(sbi)))
-					goto lock_page;
+					goto lock_folio;
 
 				if (!f2fs_cluster_is_empty(&cc))
-					goto lock_page;
+					goto lock_folio;
 
 				if (f2fs_all_cluster_page_ready(&cc,
 					pages, i, nr_pages, true))
-					goto lock_page;
+					goto lock_folio;
 
 				ret2 = f2fs_prepare_compress_overwrite(
 							inode, &pagep,
-							page->index, &fsdata);
+							folio->index, &fsdata);
 				if (ret2 < 0) {
 					ret = ret2;
 					done = 1;
 					break;
 				} else if (ret2 &&
 					(!f2fs_compress_write_end(inode,
-						fsdata, page->index, 1) ||
+						fsdata, folio->index, 1) ||
 					 !f2fs_all_cluster_page_ready(&cc,
-						pages, i, nr_pages, false))) {
+						pages, i, nr_pages,
+						false))) {
 					retry = 1;
 					break;
 				}
@@ -3059,46 +3089,47 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 				break;
 			}
 #ifdef CONFIG_F2FS_FS_COMPRESSION
-lock_page:
+lock_folio:
 #endif
-			done_index = page->index;
+			done_index = folio->index;
 retry_write:
-			lock_page(page);
+			folio_lock(folio);
 
-			if (unlikely(page->mapping != mapping)) {
+			if (unlikely(folio->mapping != mapping)) {
 continue_unlock:
-				unlock_page(page);
+				folio_unlock(folio);
 				continue;
 			}
 
-			if (!PageDirty(page)) {
+			if (!folio_test_dirty(folio)) {
 				/* someone wrote it for us */
 				goto continue_unlock;
 			}
 
-			if (PageWriteback(page)) {
+			if (folio_test_writeback(folio)) {
 				if (wbc->sync_mode != WB_SYNC_NONE)
-					f2fs_wait_on_page_writeback(page,
+					f2fs_wait_on_page_writeback(
+							&folio->page,
 							DATA, true, true);
 				else
 					goto continue_unlock;
 			}
 
-			if (!clear_page_dirty_for_io(page))
+			if (!folio_clear_dirty_for_io(folio))
 				goto continue_unlock;
 
 #ifdef CONFIG_F2FS_FS_COMPRESSION
 			if (f2fs_compressed_file(inode)) {
-				get_page(page);
-				f2fs_compress_ctx_add_page(&cc, page);
+				folio_get(folio);
+				f2fs_compress_ctx_add_page(&cc, &folio->page);
 				continue;
 			}
 #endif
-			ret = f2fs_write_single_data_page(page, &submitted,
-					&bio, &last_block, wbc, io_type,
-					0, true);
+			ret = f2fs_write_single_data_page(&folio->page,
+					&submitted, &bio, &last_block,
+					wbc, io_type, 0, true);
 			if (ret == AOP_WRITEPAGE_ACTIVATE)
-				unlock_page(page);
+				folio_unlock(folio);
 #ifdef CONFIG_F2FS_FS_COMPRESSION
 result:
 #endif
@@ -3122,7 +3153,8 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 					}
 					goto next;
 				}
-				done_index = page->index + 1;
+				done_index = folio->index +
+					folio_nr_pages(folio);
 				done = 1;
 				break;
 			}
@@ -3136,7 +3168,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 			if (need_readd)
 				goto readd;
 		}
-		release_pages(pages, nr_pages);
+		release_pages(pages,nr_pages);
 		cond_resched();
 	}
 #ifdef CONFIG_F2FS_FS_COMPRESSION
-- 
2.38.1