1 files changed, 50 insertions, 29 deletions

diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 9062adfa2fb9..12c4177f7703 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -22,6 +22,7 @@
  * Overload PG_private_2 to give us PG_fscache - this is used to indicate that
  * a page is currently backed by a local disk cache
  */
+#define folio_test_fscache(folio)	folio_test_private_2(folio)
 #define PageFsCache(page)		PagePrivate2((page))
 #define SetPageFsCache(page)		SetPagePrivate2((page))
 #define ClearPageFsCache(page)		ClearPagePrivate2((page))
@@ -29,60 +30,80 @@
 #define TestClearPageFsCache(page)	TestClearPagePrivate2((page))
 
 /**
- * set_page_fscache - Set PG_fscache on a page and take a ref
- * @page: The page.
+ * folio_start_fscache - Start an fscache write on a folio.
+ * @folio: The folio.
  *
- * Set the PG_fscache (PG_private_2) flag on a page and take the reference
- * needed for the VM to handle its lifetime correctly.  This sets the flag and
- * takes the reference unconditionally, so care must be taken not to set the
- * flag again if it's already set.
+ * Call this function before writing a folio to a local cache.  Starting a
+ * second write before the first one finishes is not allowed.
  */
-static inline void set_page_fscache(struct page *page)
+static inline void folio_start_fscache(struct folio *folio)
 {
-	set_page_private_2(page);
+	VM_BUG_ON_FOLIO(folio_test_private_2(folio), folio);
+	folio_get(folio);
+	folio_set_private_2(folio);
 }
 
 /**
- * end_page_fscache - Clear PG_fscache and release any waiters
- * @page: The page
- *
- * Clear the PG_fscache (PG_private_2) bit on a page and wake up any sleepers
- * waiting for this.  The page ref held for PG_private_2 being set is released.
+ * folio_end_fscache - End an fscache write on a folio.
+ * @folio: The folio.
  *
- * This is, for example, used when a netfs page is being written to a local
- * disk cache, thereby allowing writes to the cache for the same page to be
- * serialised.
+ * Call this function after the folio has been written to the local cache.
+ * This will wake any sleepers waiting on this folio.
  */
-static inline void end_page_fscache(struct page *page)
+static inline void folio_end_fscache(struct folio *folio)
 {
-	end_page_private_2(page);
+	folio_end_private_2(folio);
 }
 
 /**
- * wait_on_page_fscache - Wait for PG_fscache to be cleared on a page
- * @page: The page to wait on
+ * folio_wait_fscache - Wait for an fscache write on this folio to end.
+ * @folio: The folio.
  *
- * Wait for PG_fscache (aka PG_private_2) to be cleared on a page.
+ * If this folio is currently being written to a local cache, wait for
+ * the write to finish.  Another write may start after this one finishes,
+ * unless the caller holds the folio lock.
  */
-static inline void wait_on_page_fscache(struct page *page)
+static inline void folio_wait_fscache(struct folio *folio)
 {
-	wait_on_page_private_2(page);
+	folio_wait_private_2(folio);
 }
 
 /**
- * wait_on_page_fscache_killable - Wait for PG_fscache to be cleared on a page
- * @page: The page to wait on
+ * folio_wait_fscache_killable - Wait for an fscache write on this folio to end.
+ * @folio: The folio.
  *
- * Wait for PG_fscache (aka PG_private_2) to be cleared on a page or until a
- * fatal signal is received by the calling task.
+ * If this folio is currently being written to a local cache, wait
+ * for the write to finish or for a fatal signal to be received.
+ * Another write may start after this one finishes, unless the caller
+ * holds the folio lock.
  *
  * Return:
  * - 0 if successful.
  * - -EINTR if a fatal signal was encountered.
  */
+static inline int folio_wait_fscache_killable(struct folio *folio)
+{
+	return folio_wait_private_2_killable(folio);
+}
+
+static inline void set_page_fscache(struct page *page)
+{
+	folio_start_fscache(page_folio(page));
+}
+
+static inline void end_page_fscache(struct page *page)
+{
+	folio_end_private_2(page_folio(page));
+}
+
+static inline void wait_on_page_fscache(struct page *page)
+{
+	folio_wait_private_2(page_folio(page));
+}
+
 static inline int wait_on_page_fscache_killable(struct page *page)
 {
-	return wait_on_page_private_2_killable(page);
+	return folio_wait_private_2_killable(page_folio(page));
 }
 
 enum netfs_read_source {
@@ -102,6 +123,7 @@ struct netfs_cache_resources {
 	const struct netfs_cache_ops	*ops;
 	void				*cache_priv;
 	void				*cache_priv2;
+	unsigned int			debug_id;	/* Cookie debug ID */
 };
 
 /*
@@ -137,7 +159,6 @@ struct netfs_read_request {
 	struct list_head	subrequests;	/* Requests to fetch I/O from disk or net */
 	void			*netfs_priv;	/* Private data for the netfs */
 	unsigned int		debug_id;
-	unsigned int		cookie_debug_id;
 	atomic_t		nr_rd_ops;	/* Number of read ops in progress */
 	atomic_t		nr_wr_ops;	/* Number of write ops in progress */
 	size_t			submitted;	/* Amount submitted for I/O so far */