1/*
  2 *  linux/fs/ext4/symlink.c
  3 *
  4 * Only fast symlinks left here - the rest is done by generic code. AV, 1999
  5 *
  6 * Copyright (C) 1992, 1993, 1994, 1995
  7 * Remy Card (card@masi.ibp.fr)
  8 * Laboratoire MASI - Institut Blaise Pascal
  9 * Universite Pierre et Marie Curie (Paris VI)
 10 *
 11 *  from
 12 *
 13 *  linux/fs/minix/symlink.c
 14 *
 15 *  Copyright (C) 1991, 1992  Linus Torvalds
 16 *
 17 *  ext4 symlink handling code
 18 */
 19
 20#include <linux/fs.h>
 
 21#include <linux/namei.h>
 22#include "ext4.h"
 23#include "xattr.h"
 24
 25#ifdef CONFIG_EXT4_FS_ENCRYPTION
 26static const char *ext4_encrypted_get_link(struct dentry *dentry,
 27					   struct inode *inode,
 28					   struct delayed_call *done)
 29{
 30	struct page *cpage = NULL;
 31	char *caddr, *paddr = NULL;
 32	struct ext4_str cstr, pstr;
 33	struct ext4_encrypted_symlink_data *sd;
 34	loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
 35	int res;
 36	u32 plen, max_size = inode->i_sb->s_blocksize;
 37
 38	if (!dentry)
 39		return ERR_PTR(-ECHILD);
 40
 41	res = ext4_get_encryption_info(inode);
 42	if (res)
 43		return ERR_PTR(res);
 44
 45	if (ext4_inode_is_fast_symlink(inode)) {
 46		caddr = (char *) EXT4_I(inode)->i_data;
 47		max_size = sizeof(EXT4_I(inode)->i_data);
 48	} else {
 49		cpage = read_mapping_page(inode->i_mapping, 0, NULL);
 50		if (IS_ERR(cpage))
 51			return ERR_CAST(cpage);
 52		caddr = page_address(cpage);
 53		caddr[size] = 0;
 54	}
 55
 56	/* Symlink is encrypted */
 57	sd = (struct ext4_encrypted_symlink_data *)caddr;
 58	cstr.name = sd->encrypted_path;
 59	cstr.len  = le16_to_cpu(sd->len);
 60	if ((cstr.len +
 61	     sizeof(struct ext4_encrypted_symlink_data) - 1) >
 62	    max_size) {
 63		/* Symlink data on the disk is corrupted */
 64		res = -EFSCORRUPTED;
 65		goto errout;
 66	}
 67	plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ?
 68		EXT4_FNAME_CRYPTO_DIGEST_SIZE*2 : cstr.len;
 69	paddr = kmalloc(plen + 1, GFP_NOFS);
 70	if (!paddr) {
 71		res = -ENOMEM;
 72		goto errout;
 73	}
 74	pstr.name = paddr;
 75	pstr.len = plen;
 76	res = _ext4_fname_disk_to_usr(inode, NULL, &cstr, &pstr);
 77	if (res < 0)
 78		goto errout;
 79	/* Null-terminate the name */
 80	if (res <= plen)
 81		paddr[res] = '\0';
 82	if (cpage)
 83		put_page(cpage);
 84	set_delayed_call(done, kfree_link, paddr);
 85	return paddr;
 86errout:
 87	if (cpage)
 88		put_page(cpage);
 89	kfree(paddr);
 90	return ERR_PTR(res);
 91}
 92
 93const struct inode_operations ext4_encrypted_symlink_inode_operations = {
 94	.readlink	= generic_readlink,
 95	.get_link	= ext4_encrypted_get_link,
 96	.setattr	= ext4_setattr,
 97	.setxattr	= generic_setxattr,
 98	.getxattr	= generic_getxattr,
 99	.listxattr	= ext4_listxattr,
100	.removexattr	= generic_removexattr,
101};
102#endif
103
104const struct inode_operations ext4_symlink_inode_operations = {
105	.readlink	= generic_readlink,
106	.get_link	= page_get_link,
 
107	.setattr	= ext4_setattr,
108	.setxattr	= generic_setxattr,
109	.getxattr	= generic_getxattr,
110	.listxattr	= ext4_listxattr,
111	.removexattr	= generic_removexattr,
112};
113
114const struct inode_operations ext4_fast_symlink_inode_operations = {
115	.readlink	= generic_readlink,
116	.get_link	= simple_get_link,
117	.setattr	= ext4_setattr,
118	.setxattr	= generic_setxattr,
119	.getxattr	= generic_getxattr,
120	.listxattr	= ext4_listxattr,
121	.removexattr	= generic_removexattr,
122};

 1/*
 2 *  linux/fs/ext4/symlink.c
 3 *
 4 * Only fast symlinks left here - the rest is done by generic code. AV, 1999
 5 *
 6 * Copyright (C) 1992, 1993, 1994, 1995
 7 * Remy Card (card@masi.ibp.fr)
 8 * Laboratoire MASI - Institut Blaise Pascal
 9 * Universite Pierre et Marie Curie (Paris VI)
10 *
11 *  from
12 *
13 *  linux/fs/minix/symlink.c
14 *
15 *  Copyright (C) 1991, 1992  Linus Torvalds
16 *
17 *  ext4 symlink handling code
18 */
19
20#include <linux/fs.h>
21#include <linux/jbd2.h>
22#include <linux/namei.h>
23#include "ext4.h"
24#include "xattr.h"
25
26static void *ext4_follow_link(struct dentry *dentry, struct nameidata *nd)
 
 
 
27{
28	struct ext4_inode_info *ei = EXT4_I(dentry->d_inode);
29	nd_set_link(nd, (char *) ei->i_data);
30	return NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
31}
32
 
 
 
 
 
 
 
 
 
 
 
33const struct inode_operations ext4_symlink_inode_operations = {
34	.readlink	= generic_readlink,
35	.follow_link	= page_follow_link_light,
36	.put_link	= page_put_link,
37	.setattr	= ext4_setattr,
38	.setxattr	= generic_setxattr,
39	.getxattr	= generic_getxattr,
40	.listxattr	= ext4_listxattr,
41	.removexattr	= generic_removexattr,
42};
43
44const struct inode_operations ext4_fast_symlink_inode_operations = {
45	.readlink	= generic_readlink,
46	.follow_link	= ext4_follow_link,
47	.setattr	= ext4_setattr,
48	.setxattr	= generic_setxattr,
49	.getxattr	= generic_getxattr,
50	.listxattr	= ext4_listxattr,
51	.removexattr	= generic_removexattr,
52};