Subject: [PATCH 02/10] ext2: Convert ext2_check_page to ext2_check_folio

From: "Matthew Wilcox (Oracle)" <[email-masked]>
Date: Thu, 21 Sep 2023 12:31:23 -0400

Support in this function for large folios is limited to supporting
filesystems with block size > PAGE_SIZE.  This new functionality will only
be supported on machines without HIGHMEM, so the problem of kmap_local
only being able to map a single page in the folio can be ignored.
We will not use large folios for ext2 directories on HIGHMEM machines.

Signed-off-by: Matthew Wilcox (Oracle) <[email-masked]>
---
 fs/ext2/dir.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index b335f17f682f..03867381eec2 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -96,19 +96,19 @@ static void ext2_commit_chunk(struct page *page, loff_t pos, unsigned len)
 	unlock_page(page);
 }
 
-static bool ext2_check_page(struct page *page, int quiet, char *kaddr)
+static bool ext2_check_folio(struct folio *folio, int quiet, char *kaddr)
 {
-	struct inode *dir = page->mapping->host;
+	struct inode *dir = folio->mapping->host;
 	struct super_block *sb = dir->i_sb;
 	unsigned chunk_size = ext2_chunk_size(dir);
 	u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
 	unsigned offs, rec_len;
-	unsigned limit = PAGE_SIZE;
+	unsigned limit = folio_size(folio);
 	ext2_dirent *p;
 	char *error;
 
-	if ((dir->i_size >> PAGE_SHIFT) == page->index) {
-		limit = dir->i_size & ~PAGE_MASK;
+	if (dir->i_size < folio_pos(folio) + limit) {
+		limit = offset_in_folio(folio, dir->i_size);
 		if (limit & (chunk_size - 1))
 			goto Ebadsize;
 		if (!limit)
@@ -132,7 +132,7 @@ static bool ext2_check_page(struct page *page, int quiet, char *kaddr)
 	if (offs != limit)
 		goto Eend;
 out:
-	SetPageChecked(page);
+	folio_set_checked(folio);
 	return true;
 
 	/* Too bad, we had an error */
@@ -160,22 +160,22 @@ static bool ext2_check_page(struct page *page, int quiet, char *kaddr)
 bad_entry:
 	if (!quiet)
 		ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - "
-			"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
-			dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
+			"offset=%llu, inode=%lu, rec_len=%d, name_len=%d",
+			dir->i_ino, error, folio_pos(folio) + offs,
 			(unsigned long) le32_to_cpu(p->inode),
 			rec_len, p->name_len);
 	goto fail;
 Eend:
 	if (!quiet) {
 		p = (ext2_dirent *)(kaddr + offs);
-		ext2_error(sb, "ext2_check_page",
+		ext2_error(sb, "ext2_check_folio",
 			"entry in directory #%lu spans the page boundary"
-			"offset=%lu, inode=%lu",
-			dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
+			"offset=%llu, inode=%lu",
+			dir->i_ino, folio_pos(folio) + offs,
 			(unsigned long) le32_to_cpu(p->inode));
 	}
 fail:
-	SetPageError(page);
+	folio_set_error(folio);
 	return false;
 }
 
@@ -195,9 +195,9 @@ static void *ext2_get_page(struct inode *dir, unsigned long n,
 
 	if (IS_ERR(folio))
 		return ERR_CAST(folio);
-	page_addr = kmap_local_folio(folio, n & (folio_nr_pages(folio) - 1));
+	page_addr = kmap_local_folio(folio, 0);
 	if (unlikely(!folio_test_checked(folio))) {
-		if (!ext2_check_page(&folio->page, quiet, page_addr))
+		if (!ext2_check_folio(folio, quiet, page_addr))
 			goto fail;
 	}
 	*page = &folio->page;
-- 
2.40.1