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86 lines
2.4 KiB
86 lines
2.4 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* Copyright (C) 2019 HUAWEI, Inc. |
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* https://www.huawei.com/ |
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*/ |
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#ifndef __EROFS_FS_COMPRESS_H |
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#define __EROFS_FS_COMPRESS_H |
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#include "internal.h" |
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enum { |
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Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX, |
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Z_EROFS_COMPRESSION_RUNTIME_MAX |
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}; |
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struct z_erofs_decompress_req { |
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struct super_block *sb; |
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struct page **in, **out; |
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unsigned short pageofs_out; |
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unsigned int inputsize, outputsize; |
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/* indicate the algorithm will be used for decompression */ |
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unsigned int alg; |
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bool inplace_io, partial_decoding; |
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}; |
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/* some special page->private (unsigned long, see below) */ |
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#define Z_EROFS_SHORTLIVED_PAGE (-1UL << 2) |
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#define Z_EROFS_PREALLOCATED_PAGE (-2UL << 2) |
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/* |
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* For all pages in a pcluster, page->private should be one of |
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* Type Last 2bits page->private |
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* short-lived page 00 Z_EROFS_SHORTLIVED_PAGE |
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* preallocated page (tryalloc) 00 Z_EROFS_PREALLOCATED_PAGE |
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* cached/managed page 00 pointer to z_erofs_pcluster |
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* online page (file-backed, 01/10/11 sub-index << 2 | count |
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* some pages can be used for inplace I/O) |
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* |
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* page->mapping should be one of |
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* Type page->mapping |
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* short-lived page NULL |
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* preallocated page NULL |
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* cached/managed page non-NULL or NULL (invalidated/truncated page) |
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* online page non-NULL |
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* |
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* For all managed pages, PG_private should be set with 1 extra refcount, |
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* which is used for page reclaim / migration. |
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*/ |
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/* |
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* short-lived pages are pages directly from buddy system with specific |
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* page->private (no need to set PagePrivate since these are non-LRU / |
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* non-movable pages and bypass reclaim / migration code). |
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*/ |
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static inline bool z_erofs_is_shortlived_page(struct page *page) |
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{ |
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if (page->private != Z_EROFS_SHORTLIVED_PAGE) |
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return false; |
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DBG_BUGON(page->mapping); |
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return true; |
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} |
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static inline bool z_erofs_put_shortlivedpage(struct list_head *pagepool, |
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struct page *page) |
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{ |
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if (!z_erofs_is_shortlived_page(page)) |
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return false; |
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/* short-lived pages should not be used by others at the same time */ |
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if (page_ref_count(page) > 1) { |
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put_page(page); |
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} else { |
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/* follow the pcluster rule above. */ |
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set_page_private(page, 0); |
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list_add(&page->lru, pagepool); |
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} |
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return true; |
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} |
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int z_erofs_decompress(struct z_erofs_decompress_req *rq, |
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struct list_head *pagepool); |
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#endif
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