1 files changed, 63 insertions, 25 deletions

diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
index 07d279fd5d67..26fa170090b8 100644
--- a/fs/erofs/compress.h
+++ b/fs/erofs/compress.h
@@ -1,60 +1,98 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Copyright (C) 2019 HUAWEI, Inc.
- *             http://www.huawei.com/
- * Created by Gao Xiang <gaoxiang25@huawei.com>
+ *             https://www.huawei.com/
  */
 #ifndef __EROFS_FS_COMPRESS_H
 #define __EROFS_FS_COMPRESS_H
 
 #include "internal.h"
 
-enum {
-	Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
-	Z_EROFS_COMPRESSION_RUNTIME_MAX
-};
-
 struct z_erofs_decompress_req {
 	struct super_block *sb;
 	struct page **in, **out;
 
-	unsigned short pageofs_out;
+	unsigned short pageofs_in, pageofs_out;
 	unsigned int inputsize, outputsize;
 
 	/* indicate the algorithm will be used for decompression */
 	unsigned int alg;
-	bool inplace_io, partial_decoding;
+	bool inplace_io, partial_decoding, fillgaps;
+};
+
+struct z_erofs_decompressor {
+	int (*decompress)(struct z_erofs_decompress_req *rq,
+			  struct page **pagepool);
+	char *name;
 };
 
+/* some special page->private (unsigned long, see below) */
+#define Z_EROFS_SHORTLIVED_PAGE		(-1UL << 2)
+#define Z_EROFS_PREALLOCATED_PAGE	(-2UL << 2)
+
 /*
- * - 0x5A110C8D ('sallocated', Z_EROFS_MAPPING_STAGING) -
- * used to mark temporary allocated pages from other
- * file/cached pages and NULL mapping pages.
+ * For all pages in a pcluster, page->private should be one of
+ * Type                         Last 2bits      page->private
+ * short-lived page             00              Z_EROFS_SHORTLIVED_PAGE
+ * preallocated page (tryalloc) 00              Z_EROFS_PREALLOCATED_PAGE
+ * cached/managed page          00              pointer to z_erofs_pcluster
+ * online page (file-backed,    01/10/11        sub-index << 2 | count
+ *              some pages can be used for inplace I/O)
+ *
+ * page->mapping should be one of
+ * Type                 page->mapping
+ * short-lived page     NULL
+ * preallocated page    NULL
+ * cached/managed page  non-NULL or NULL (invalidated/truncated page)
+ * online page          non-NULL
+ *
+ * For all managed pages, PG_private should be set with 1 extra refcount,
+ * which is used for page reclaim / migration.
  */
-#define Z_EROFS_MAPPING_STAGING         ((void *)0x5A110C8D)
 
-/* check if a page is marked as staging */
-static inline bool z_erofs_page_is_staging(struct page *page)
+/*
+ * short-lived pages are pages directly from buddy system with specific
+ * page->private (no need to set PagePrivate since these are non-LRU /
+ * non-movable pages and bypass reclaim / migration code).
+ */
+static inline bool z_erofs_is_shortlived_page(struct page *page)
 {
-	return page->mapping == Z_EROFS_MAPPING_STAGING;
+	if (page->private != Z_EROFS_SHORTLIVED_PAGE)
+		return false;
+
+	DBG_BUGON(page->mapping);
+	return true;
 }
 
-static inline bool z_erofs_put_stagingpage(struct list_head *pagepool,
-					   struct page *page)
+static inline bool z_erofs_put_shortlivedpage(struct page **pagepool,
+					      struct page *page)
 {
-	if (!z_erofs_page_is_staging(page))
+	if (!z_erofs_is_shortlived_page(page))
 		return false;
 
-	/* staging pages should not be used by others at the same time */
-	if (page_ref_count(page) > 1)
+	/* short-lived pages should not be used by others at the same time */
+	if (page_ref_count(page) > 1) {
 		put_page(page);
-	else
-		list_add(&page->lru, pagepool);
+	} else {
+		/* follow the pcluster rule above. */
+		erofs_pagepool_add(pagepool, page);
+	}
 	return true;
 }
 
+#define MNGD_MAPPING(sbi)	((sbi)->managed_cache->i_mapping)
+static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi,
+					 struct page *page)
+{
+	return page->mapping == MNGD_MAPPING(sbi);
+}
+
+int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
+			 unsigned int padbufsize);
 int z_erofs_decompress(struct z_erofs_decompress_req *rq,
-		       struct list_head *pagepool);
+		       struct page **pagepool);
 
+/* prototypes for specific algorithms */
+int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
+			    struct page **pagepool);
 #endif
-