1 files changed, 57 insertions, 0 deletions
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 81b0485fd22a..14d5d75f4b6e 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -812,6 +812,7 @@ struct afs_operation {
 			pgoff_t		last;		/* last page in mapping to deal with */
 			unsigned	first_offset;	/* offset into mapping[first] */
 			unsigned	last_to;	/* amount of mapping[last] */
+			bool		laundering;	/* Laundering page, PG_writeback not set */
 		} store;
 		struct {
 			struct iattr	*attr;
@@ -857,6 +858,62 @@ struct afs_vnode_cache_aux {
 	u64			data_version;
 } __packed;
 
+/*
+ * We use page->private to hold the amount of the page that we've written to,
+ * splitting the field into two parts.  However, we need to represent a range
+ * 0...PAGE_SIZE, so we reduce the resolution if the size of the page
+ * exceeds what we can encode.
+ */
+#ifdef CONFIG_64BIT
+#define __AFS_PAGE_PRIV_MASK	0x7fffffffUL
+#define __AFS_PAGE_PRIV_SHIFT	32
+#define __AFS_PAGE_PRIV_MMAPPED	0x80000000UL
+#else
+#define __AFS_PAGE_PRIV_MASK	0x7fffUL
+#define __AFS_PAGE_PRIV_SHIFT	16
+#define __AFS_PAGE_PRIV_MMAPPED	0x8000UL
+#endif
+
+static inline unsigned int afs_page_dirty_resolution(void)
+{
+	int shift = PAGE_SHIFT - (__AFS_PAGE_PRIV_SHIFT - 1);
+	return (shift > 0) ? shift : 0;
+}
+
+static inline size_t afs_page_dirty_from(unsigned long priv)
+{
+	unsigned long x = priv & __AFS_PAGE_PRIV_MASK;
+
+	/* The lower bound is inclusive */
+	return x << afs_page_dirty_resolution();
+}
+
+static inline size_t afs_page_dirty_to(unsigned long priv)
+{
+	unsigned long x = (priv >> __AFS_PAGE_PRIV_SHIFT) & __AFS_PAGE_PRIV_MASK;
+
+	/* The upper bound is immediately beyond the region */
+	return (x + 1) << afs_page_dirty_resolution();
+}
+
+static inline unsigned long afs_page_dirty(size_t from, size_t to)
+{
+	unsigned int res = afs_page_dirty_resolution();
+	from >>= res;
+	to = (to - 1) >> res;
+	return (to << __AFS_PAGE_PRIV_SHIFT) | from;
+}
+
+static inline unsigned long afs_page_dirty_mmapped(unsigned long priv)
+{
+	return priv | __AFS_PAGE_PRIV_MMAPPED;
+}
+
+static inline bool afs_is_page_dirty_mmapped(unsigned long priv)
+{
+	return priv & __AFS_PAGE_PRIV_MMAPPED;
+}
+
 #include <trace/events/afs.h>
 
 /*****************************************************************************/