Thomas Gleixner | 20c8ccb | 2019-06-04 10:11:32 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 2 | /* |
| 3 | * Copyright (c) 2013 |
| 4 | * Phillip Lougher <phillip@squashfs.org.uk> |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 5 | */ |
| 6 | |
| 7 | #include <linux/fs.h> |
| 8 | #include <linux/vfs.h> |
| 9 | #include <linux/kernel.h> |
| 10 | #include <linux/slab.h> |
| 11 | #include <linux/string.h> |
| 12 | #include <linux/pagemap.h> |
| 13 | #include <linux/mutex.h> |
| 14 | |
| 15 | #include "squashfs_fs.h" |
| 16 | #include "squashfs_fs_sb.h" |
| 17 | #include "squashfs_fs_i.h" |
| 18 | #include "squashfs.h" |
| 19 | #include "page_actor.h" |
| 20 | |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 21 | /* Read separately compressed datablock directly into page cache */ |
Phillip Lougher | a3f94cb | 2018-08-02 16:45:15 +0100 | [diff] [blame] | 22 | int squashfs_readpage_block(struct page *target_page, u64 block, int bsize, |
| 23 | int expected) |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 24 | |
| 25 | { |
| 26 | struct inode *inode = target_page->mapping->host; |
| 27 | struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info; |
| 28 | |
Phillip Lougher | 12427de | 2023-11-13 16:09:01 +0000 | [diff] [blame] | 29 | loff_t file_end = (i_size_read(inode) - 1) >> PAGE_SHIFT; |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 30 | int mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1; |
Phillip Lougher | 12427de | 2023-11-13 16:09:01 +0000 | [diff] [blame] | 31 | loff_t start_index = target_page->index & ~mask; |
| 32 | loff_t end_index = start_index | mask; |
Phillip Lougher | 1bb1a07 | 2022-06-11 04:21:33 +0100 | [diff] [blame] | 33 | int i, n, pages, bytes, res = -ENOMEM; |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 34 | struct page **page; |
| 35 | struct squashfs_page_actor *actor; |
| 36 | void *pageaddr; |
| 37 | |
| 38 | if (end_index > file_end) |
| 39 | end_index = file_end; |
| 40 | |
| 41 | pages = end_index - start_index + 1; |
| 42 | |
Fabian Frederick | 1469488 | 2014-08-06 16:03:50 -0700 | [diff] [blame] | 43 | page = kmalloc_array(pages, sizeof(void *), GFP_KERNEL); |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 44 | if (page == NULL) |
| 45 | return res; |
| 46 | |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 47 | /* Try to grab all the pages covered by the Squashfs block */ |
Phillip Lougher | 1bb1a07 | 2022-06-11 04:21:33 +0100 | [diff] [blame] | 48 | for (i = 0, n = start_index; n <= end_index; n++) { |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 49 | page[i] = (n == target_page->index) ? target_page : |
| 50 | grab_cache_page_nowait(target_page->mapping, n); |
| 51 | |
Phillip Lougher | 1bb1a07 | 2022-06-11 04:21:33 +0100 | [diff] [blame] | 52 | if (page[i] == NULL) |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 53 | continue; |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 54 | |
| 55 | if (PageUptodate(page[i])) { |
| 56 | unlock_page(page[i]); |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 57 | put_page(page[i]); |
Phillip Lougher | 1bb1a07 | 2022-06-11 04:21:33 +0100 | [diff] [blame] | 58 | continue; |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 59 | } |
Phillip Lougher | 1bb1a07 | 2022-06-11 04:21:33 +0100 | [diff] [blame] | 60 | |
| 61 | i++; |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 62 | } |
| 63 | |
Phillip Lougher | 1bb1a07 | 2022-06-11 04:21:33 +0100 | [diff] [blame] | 64 | pages = i; |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 65 | |
Phillip Lougher | f268eed | 2022-06-11 04:21:32 +0100 | [diff] [blame] | 66 | /* |
| 67 | * Create a "page actor" which will kmap and kunmap the |
| 68 | * page cache pages appropriately within the decompressor |
| 69 | */ |
Phillip Lougher | 1bb1a07 | 2022-06-11 04:21:33 +0100 | [diff] [blame] | 70 | actor = squashfs_page_actor_init_special(msblk, page, pages, expected); |
Phillip Lougher | f268eed | 2022-06-11 04:21:32 +0100 | [diff] [blame] | 71 | if (actor == NULL) |
| 72 | goto out; |
| 73 | |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 74 | /* Decompress directly into the page cache buffers */ |
| 75 | res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor); |
Phillip Lougher | f268eed | 2022-06-11 04:21:32 +0100 | [diff] [blame] | 76 | |
Phillip Lougher | 1f13dff | 2022-08-22 22:54:30 +0100 | [diff] [blame] | 77 | squashfs_page_actor_free(actor); |
Phillip Lougher | f268eed | 2022-06-11 04:21:32 +0100 | [diff] [blame] | 78 | |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 79 | if (res < 0) |
| 80 | goto mark_errored; |
| 81 | |
Phillip Lougher | a3f94cb | 2018-08-02 16:45:15 +0100 | [diff] [blame] | 82 | if (res != expected) { |
| 83 | res = -EIO; |
| 84 | goto mark_errored; |
| 85 | } |
| 86 | |
Phillip Lougher | 1bb1a07 | 2022-06-11 04:21:33 +0100 | [diff] [blame] | 87 | /* Last page (if present) may have trailing bytes not filled */ |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 88 | bytes = res % PAGE_SIZE; |
Phillip Lougher | 1bb1a07 | 2022-06-11 04:21:33 +0100 | [diff] [blame] | 89 | if (page[pages - 1]->index == end_index && bytes) { |
| 90 | pageaddr = kmap_local_page(page[pages - 1]); |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 91 | memset(pageaddr + bytes, 0, PAGE_SIZE - bytes); |
Phillip Lougher | 1bb1a07 | 2022-06-11 04:21:33 +0100 | [diff] [blame] | 92 | kunmap_local(pageaddr); |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 93 | } |
| 94 | |
| 95 | /* Mark pages as uptodate, unlock and release */ |
| 96 | for (i = 0; i < pages; i++) { |
| 97 | flush_dcache_page(page[i]); |
| 98 | SetPageUptodate(page[i]); |
| 99 | unlock_page(page[i]); |
| 100 | if (page[i] != target_page) |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 101 | put_page(page[i]); |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 102 | } |
| 103 | |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 104 | kfree(page); |
| 105 | |
| 106 | return 0; |
| 107 | |
| 108 | mark_errored: |
Matthew Wilcox (Oracle) | bbf45b7 | 2024-04-20 03:50:18 +0100 | [diff] [blame] | 109 | /* Decompression failed. Target_page is |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 110 | * dealt with by the caller |
| 111 | */ |
| 112 | for (i = 0; i < pages; i++) { |
Phillip Lougher | 6d56540 | 2013-11-24 00:40:49 +0000 | [diff] [blame] | 113 | if (page[i] == NULL || page[i] == target_page) |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 114 | continue; |
| 115 | flush_dcache_page(page[i]); |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 116 | unlock_page(page[i]); |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 117 | put_page(page[i]); |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 118 | } |
| 119 | |
| 120 | out: |
Phillip Lougher | 0d455c1 | 2013-11-13 02:04:19 +0000 | [diff] [blame] | 121 | kfree(page); |
| 122 | return res; |
| 123 | } |