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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /fs/squashfs/file_direct.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/squashfs/file_direct.c')
-rw-r--r--fs/squashfs/file_direct.c124
1 files changed, 124 insertions, 0 deletions
diff --git a/fs/squashfs/file_direct.c b/fs/squashfs/file_direct.c
new file mode 100644
index 0000000000..f1ccad519e
--- /dev/null
+++ b/fs/squashfs/file_direct.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2013
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/pagemap.h>
+#include <linux/mutex.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "page_actor.h"
+
+/* Read separately compressed datablock directly into page cache */
+int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
+ int expected)
+
+{
+ struct inode *inode = target_page->mapping->host;
+ struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+
+ int file_end = (i_size_read(inode) - 1) >> PAGE_SHIFT;
+ int mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1;
+ int start_index = target_page->index & ~mask;
+ int end_index = start_index | mask;
+ int i, n, pages, bytes, res = -ENOMEM;
+ struct page **page;
+ struct squashfs_page_actor *actor;
+ void *pageaddr;
+
+ if (end_index > file_end)
+ end_index = file_end;
+
+ pages = end_index - start_index + 1;
+
+ page = kmalloc_array(pages, sizeof(void *), GFP_KERNEL);
+ if (page == NULL)
+ return res;
+
+ /* Try to grab all the pages covered by the Squashfs block */
+ for (i = 0, n = start_index; n <= end_index; n++) {
+ page[i] = (n == target_page->index) ? target_page :
+ grab_cache_page_nowait(target_page->mapping, n);
+
+ if (page[i] == NULL)
+ continue;
+
+ if (PageUptodate(page[i])) {
+ unlock_page(page[i]);
+ put_page(page[i]);
+ continue;
+ }
+
+ i++;
+ }
+
+ pages = i;
+
+ /*
+ * Create a "page actor" which will kmap and kunmap the
+ * page cache pages appropriately within the decompressor
+ */
+ actor = squashfs_page_actor_init_special(msblk, page, pages, expected);
+ if (actor == NULL)
+ goto out;
+
+ /* Decompress directly into the page cache buffers */
+ res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
+
+ squashfs_page_actor_free(actor);
+
+ if (res < 0)
+ goto mark_errored;
+
+ if (res != expected) {
+ res = -EIO;
+ goto mark_errored;
+ }
+
+ /* Last page (if present) may have trailing bytes not filled */
+ bytes = res % PAGE_SIZE;
+ if (page[pages - 1]->index == end_index && bytes) {
+ pageaddr = kmap_local_page(page[pages - 1]);
+ memset(pageaddr + bytes, 0, PAGE_SIZE - bytes);
+ kunmap_local(pageaddr);
+ }
+
+ /* Mark pages as uptodate, unlock and release */
+ for (i = 0; i < pages; i++) {
+ flush_dcache_page(page[i]);
+ SetPageUptodate(page[i]);
+ unlock_page(page[i]);
+ if (page[i] != target_page)
+ put_page(page[i]);
+ }
+
+ kfree(page);
+
+ return 0;
+
+mark_errored:
+ /* Decompression failed, mark pages as errored. Target_page is
+ * dealt with by the caller
+ */
+ for (i = 0; i < pages; i++) {
+ if (page[i] == NULL || page[i] == target_page)
+ continue;
+ flush_dcache_page(page[i]);
+ SetPageError(page[i]);
+ unlock_page(page[i]);
+ put_page(page[i]);
+ }
+
+out:
+ kfree(page);
+ return res;
+}