Four folio-related fixes for 5.19:

- Mark a folio accessed at the right time (Yu Kuai)
 
  - Fix a race for folios being replaced in the middle of a read (Brian Foster)
 
  - Clear folio->private in more places (Xiubo Li)
 
  - Take the invalidate_lock in page_cache_ra_order() (Alistair Popple)
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Merge tag 'folio-5.19b' of git://git.infradead.org/users/willy/pagecache

Pull pagecache fixes from Matthew Wilcox:
 "Four folio-related fixes for 5.19:

   - Mark a folio accessed at the right time (Yu Kuai)

   - Fix a race for folios being replaced in the middle of a read (Brian
     Foster)

   - Clear folio->private in more places (Xiubo Li)

   - Take the invalidate_lock in page_cache_ra_order() (Alistair Popple)"

* tag 'folio-5.19b' of git://git.infradead.org/users/willy/pagecache:
  filemap: Fix serialization adding transparent huge pages to page cache
  mm: Clear page->private when splitting or migrating a page
  filemap: Handle sibling entries in filemap_get_read_batch()
  filemap: Correct the conditions for marking a folio as accessed

mm/filemap.c

@@ -2385,6 +2385,8 @@ static void filemap_get_read_batch(struct address_space *mapping,
 			continue;
 		if (xas.xa_index > max || xa_is_value(folio))
 			break;
+		if (xa_is_sibling(folio))
+			break;
 		if (!folio_try_get_rcu(folio))
 			goto retry;
 
@@ -2629,6 +2631,13 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
 	return err;
 }
 
+static inline bool pos_same_folio(loff_t pos1, loff_t pos2, struct folio *folio)
+{
+	unsigned int shift = folio_shift(folio);
+
+	return (pos1 >> shift == pos2 >> shift);
+}
+
 /**
  * filemap_read - Read data from the page cache.
  * @iocb: The iocb to read.
@@ -2700,11 +2709,11 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
 		writably_mapped = mapping_writably_mapped(mapping);
 
 		/*
-		 * When a sequential read accesses a page several times, only
+		 * When a read accesses the same folio several times, only
 		 * mark it as accessed the first time.
 		 */
-		if (iocb->ki_pos >> PAGE_SHIFT !=
-		    ra->prev_pos >> PAGE_SHIFT)
+		if (!pos_same_folio(iocb->ki_pos, ra->prev_pos - 1,
+							fbatch.folios[0]))
 			folio_mark_accessed(fbatch.folios[0]);
 
 		for (i = 0; i < folio_batch_count(&fbatch); i++) {

mm/huge_memory.c

@@ -2377,6 +2377,7 @@ static void __split_huge_page_tail(struct page *head, int tail,
 			page_tail);
 	page_tail->mapping = head->mapping;
 	page_tail->index = head->index + tail;
+	page_tail->private = 0;
 
 	/* Page flags must be visible before we make the page non-compound. */
 	smp_wmb();

mm/migrate.c

@@ -1106,6 +1106,7 @@ static int unmap_and_move(new_page_t get_new_page,
 	if (!newpage)
 		return -ENOMEM;
 
+	newpage->private = 0;
 	rc = __unmap_and_move(page, newpage, force, mode);
 	if (rc == MIGRATEPAGE_SUCCESS)
 		set_page_owner_migrate_reason(newpage, reason);

mm/readahead.c

@@ -510,6 +510,7 @@ void page_cache_ra_order(struct readahead_control *ractl,
 			new_order--;
 	}
 
+	filemap_invalidate_lock_shared(mapping);
 	while (index <= limit) {
 		unsigned int order = new_order;
 
@@ -536,6 +537,7 @@ void page_cache_ra_order(struct readahead_control *ractl,
 	}
 
 	read_pages(ractl);
+	filemap_invalidate_unlock_shared(mapping);
 
 	/*
 	 * If there were already pages in the page cache, then we may have