120c8ccb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
20d455c12SPhillip Lougher /*
30d455c12SPhillip Lougher * Copyright (c) 2013
40d455c12SPhillip Lougher * Phillip Lougher <phillip@squashfs.org.uk>
50d455c12SPhillip Lougher */
60d455c12SPhillip Lougher
70d455c12SPhillip Lougher #include <linux/fs.h>
80d455c12SPhillip Lougher #include <linux/vfs.h>
90d455c12SPhillip Lougher #include <linux/kernel.h>
100d455c12SPhillip Lougher #include <linux/slab.h>
110d455c12SPhillip Lougher #include <linux/string.h>
120d455c12SPhillip Lougher #include <linux/pagemap.h>
130d455c12SPhillip Lougher #include <linux/mutex.h>
140d455c12SPhillip Lougher
150d455c12SPhillip Lougher #include "squashfs_fs.h"
160d455c12SPhillip Lougher #include "squashfs_fs_sb.h"
170d455c12SPhillip Lougher #include "squashfs_fs_i.h"
180d455c12SPhillip Lougher #include "squashfs.h"
190d455c12SPhillip Lougher #include "page_actor.h"
200d455c12SPhillip Lougher
210d455c12SPhillip Lougher /* Read separately compressed datablock directly into page cache */
squashfs_readpage_block(struct page * target_page,u64 block,int bsize,int expected)22a3f94cb9SPhillip Lougher int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
23a3f94cb9SPhillip Lougher int expected)
240d455c12SPhillip Lougher
250d455c12SPhillip Lougher {
267f73fcdeSPhillip Lougher struct folio *folio = page_folio(target_page);
270d455c12SPhillip Lougher struct inode *inode = target_page->mapping->host;
280d455c12SPhillip Lougher struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
2912427de9SPhillip Lougher loff_t file_end = (i_size_read(inode) - 1) >> PAGE_SHIFT;
3009cbfeafSKirill A. Shutemov int mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1;
317f73fcdeSPhillip Lougher loff_t start_index = folio->index & ~mask;
3212427de9SPhillip Lougher loff_t end_index = start_index | mask;
331bb1a07aSPhillip Lougher int i, n, pages, bytes, res = -ENOMEM;
347f73fcdeSPhillip Lougher struct page **page, *last_page;
350d455c12SPhillip Lougher struct squashfs_page_actor *actor;
360d455c12SPhillip Lougher void *pageaddr;
370d455c12SPhillip Lougher
380d455c12SPhillip Lougher if (end_index > file_end)
390d455c12SPhillip Lougher end_index = file_end;
400d455c12SPhillip Lougher
410d455c12SPhillip Lougher pages = end_index - start_index + 1;
420d455c12SPhillip Lougher
4314694888SFabian Frederick page = kmalloc_array(pages, sizeof(void *), GFP_KERNEL);
440d455c12SPhillip Lougher if (page == NULL)
450d455c12SPhillip Lougher return res;
460d455c12SPhillip Lougher
470d455c12SPhillip Lougher /* Try to grab all the pages covered by the Squashfs block */
481bb1a07aSPhillip Lougher for (i = 0, n = start_index; n <= end_index; n++) {
497f73fcdeSPhillip Lougher page[i] = (n == folio->index) ? target_page :
500d455c12SPhillip Lougher grab_cache_page_nowait(target_page->mapping, n);
510d455c12SPhillip Lougher
521bb1a07aSPhillip Lougher if (page[i] == NULL)
530d455c12SPhillip Lougher continue;
540d455c12SPhillip Lougher
550d455c12SPhillip Lougher if (PageUptodate(page[i])) {
560d455c12SPhillip Lougher unlock_page(page[i]);
5709cbfeafSKirill A. Shutemov put_page(page[i]);
581bb1a07aSPhillip Lougher continue;
590d455c12SPhillip Lougher }
600d455c12SPhillip Lougher
611bb1a07aSPhillip Lougher i++;
620d455c12SPhillip Lougher }
630d455c12SPhillip Lougher
641bb1a07aSPhillip Lougher pages = i;
651bb1a07aSPhillip Lougher
66f268eeddSPhillip Lougher /*
67f268eeddSPhillip Lougher * Create a "page actor" which will kmap and kunmap the
68f268eeddSPhillip Lougher * page cache pages appropriately within the decompressor
69f268eeddSPhillip Lougher */
702258e22fSPhillip Lougher actor = squashfs_page_actor_init_special(msblk, page, pages, expected,
712258e22fSPhillip Lougher start_index << PAGE_SHIFT);
72f268eeddSPhillip Lougher if (actor == NULL)
73f268eeddSPhillip Lougher goto out;
74f268eeddSPhillip Lougher
750d455c12SPhillip Lougher /* Decompress directly into the page cache buffers */
760d455c12SPhillip Lougher res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
77f268eeddSPhillip Lougher
787f73fcdeSPhillip Lougher last_page = squashfs_page_actor_free(actor);
79f268eeddSPhillip Lougher
800d455c12SPhillip Lougher if (res < 0)
810d455c12SPhillip Lougher goto mark_errored;
820d455c12SPhillip Lougher
83*84e0e03bSPhillip Lougher if (res != expected || IS_ERR(last_page)) {
84a3f94cb9SPhillip Lougher res = -EIO;
85a3f94cb9SPhillip Lougher goto mark_errored;
86a3f94cb9SPhillip Lougher }
87a3f94cb9SPhillip Lougher
881bb1a07aSPhillip Lougher /* Last page (if present) may have trailing bytes not filled */
8909cbfeafSKirill A. Shutemov bytes = res % PAGE_SIZE;
907f73fcdeSPhillip Lougher if (end_index == file_end && last_page && bytes) {
917f73fcdeSPhillip Lougher pageaddr = kmap_local_page(last_page);
9209cbfeafSKirill A. Shutemov memset(pageaddr + bytes, 0, PAGE_SIZE - bytes);
931bb1a07aSPhillip Lougher kunmap_local(pageaddr);
940d455c12SPhillip Lougher }
950d455c12SPhillip Lougher
960d455c12SPhillip Lougher /* Mark pages as uptodate, unlock and release */
970d455c12SPhillip Lougher for (i = 0; i < pages; i++) {
980d455c12SPhillip Lougher flush_dcache_page(page[i]);
990d455c12SPhillip Lougher SetPageUptodate(page[i]);
1000d455c12SPhillip Lougher unlock_page(page[i]);
1010d455c12SPhillip Lougher if (page[i] != target_page)
10209cbfeafSKirill A. Shutemov put_page(page[i]);
1030d455c12SPhillip Lougher }
1040d455c12SPhillip Lougher
1050d455c12SPhillip Lougher kfree(page);
1060d455c12SPhillip Lougher
1070d455c12SPhillip Lougher return 0;
1080d455c12SPhillip Lougher
1090d455c12SPhillip Lougher mark_errored:
110bbf45b7eSMatthew Wilcox (Oracle) /* Decompression failed. Target_page is
1110d455c12SPhillip Lougher * dealt with by the caller
1120d455c12SPhillip Lougher */
1130d455c12SPhillip Lougher for (i = 0; i < pages; i++) {
1146d565409SPhillip Lougher if (page[i] == NULL || page[i] == target_page)
1150d455c12SPhillip Lougher continue;
1160d455c12SPhillip Lougher flush_dcache_page(page[i]);
1170d455c12SPhillip Lougher unlock_page(page[i]);
11809cbfeafSKirill A. Shutemov put_page(page[i]);
1190d455c12SPhillip Lougher }
1200d455c12SPhillip Lougher
1210d455c12SPhillip Lougher out:
1220d455c12SPhillip Lougher kfree(page);
1230d455c12SPhillip Lougher return res;
1240d455c12SPhillip Lougher }
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