cregit-Linux how code gets into the kernel

Release 4.10 fs/squashfs/symlink.c

Directory: fs/squashfs
 * Squashfs - a compressed read only filesystem for Linux
 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
 * Phillip Lougher <>
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2,
 * or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * symlink.c

 * This file implements code to handle symbolic links.
 * The data contents of symbolic links are stored inside the symbolic
 * link inode within the inode table.  This allows the normally small symbolic
 * link to be compressed as part of the inode table, achieving much greater
 * compression than if the symbolic link was compressed individually.

#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>

#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "xattr.h"

static int squashfs_symlink_readpage(struct file *file, struct page *page) { struct inode *inode = page->mapping->host; struct super_block *sb = inode->i_sb; struct squashfs_sb_info *msblk = sb->s_fs_info; int index = page->index << PAGE_SHIFT; u64 block = squashfs_i(inode)->start; int offset = squashfs_i(inode)->offset; int length = min_t(int, i_size_read(inode) - index, PAGE_SIZE); int bytes, copied; void *pageaddr; struct squashfs_cache_entry *entry; TRACE("Entered squashfs_symlink_readpage, page index %ld, start block " "%llx, offset %x\n", page->index, block, offset); /* * Skip index bytes into symlink metadata. */ if (index) { bytes = squashfs_read_metadata(sb, NULL, &block, &offset, index); if (bytes < 0) { ERROR("Unable to read symlink [%llx:%x]\n", squashfs_i(inode)->start, squashfs_i(inode)->offset); goto error_out; } } /* * Read length bytes from symlink metadata. Squashfs_read_metadata * is not used here because it can sleep and we want to use * kmap_atomic to map the page. Instead call the underlying * squashfs_cache_get routine. As length bytes may overlap metadata * blocks, we may need to call squashfs_cache_get multiple times. */ for (bytes = 0; bytes < length; offset = 0, bytes += copied) { entry = squashfs_cache_get(sb, msblk->block_cache, block, 0); if (entry->error) { ERROR("Unable to read symlink [%llx:%x]\n", squashfs_i(inode)->start, squashfs_i(inode)->offset); squashfs_cache_put(entry); goto error_out; } pageaddr = kmap_atomic(page); copied = squashfs_copy_data(pageaddr + bytes, entry, offset, length - bytes); if (copied == length - bytes) memset(pageaddr + length, 0, PAGE_SIZE - length); else block = entry->next_index; kunmap_atomic(pageaddr); squashfs_cache_put(entry); } flush_dcache_page(page); SetPageUptodate(page); unlock_page(page); return 0; error_out: SetPageError(page); unlock_page(page); return 0; }


phillip lougherphillip lougher33699.12%150.00%
kirill a. shutemovkirill a. shutemov30.88%150.00%

const struct address_space_operations squashfs_symlink_aops = { .readpage = squashfs_symlink_readpage }; const struct inode_operations squashfs_symlink_inode_ops = { .get_link = page_get_link, .listxattr = squashfs_listxattr };

Overall Contributors

phillip lougherphillip lougher39898.76%466.67%
kirill a. shutemovkirill a. shutemov30.74%116.67%
al viroal viro20.50%116.67%
Directory: fs/squashfs
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