1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
|
/*
* cache.c
*
* Copyright (C) 1997 by Bill Hawes
*
* Routines to support directory cacheing using the page cache.
* This cache code is almost directly taken from ncpfs.
*
* Please add a note about your changes to smbfs in the ChangeLog file.
*/
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/dirent.h>
#include <linux/smb_fs.h>
#include <linux/pagemap.h>
#include <asm/page.h>
#include "smb_debug.h"
/*
* Force the next attempt to use the cache to be a timeout.
* If we can't find the page that's fine, it will cause a refresh.
*/
void
smb_invalid_dir_cache(struct inode * dir)
{
struct smb_sb_info *server = server_from_inode(dir);
union smb_dir_cache *cache = NULL;
struct page *page = NULL;
page = grab_cache_page(&dir->i_data, 0);
if (!page)
goto out;
if (!Page_Uptodate(page))
goto out_unlock;
cache = kmap(page);
cache->head.time = jiffies - SMB_MAX_AGE(server);
kunmap(page);
SetPageUptodate(page);
out_unlock:
UnlockPage(page);
page_cache_release(page);
out:
}
/*
* Mark all dentries for 'parent' as invalid, forcing them to be re-read
*/
void
smb_invalidate_dircache_entries(struct dentry *parent)
{
struct smb_sb_info *server = server_from_dentry(parent);
struct list_head *next;
struct dentry *dentry;
spin_lock(&dcache_lock);
next = parent->d_subdirs.next;
while (next != &parent->d_subdirs) {
dentry = list_entry(next, struct dentry, d_child);
dentry->d_fsdata = NULL;
smb_age_dentry(server, dentry);
next = next->next;
}
spin_unlock(&dcache_lock);
}
static int
smb_d_validate(struct dentry *dentry)
{
unsigned long dent_addr = (unsigned long) dentry;
unsigned long min_addr = PAGE_OFFSET;
unsigned long align_mask = 0x0F;
unsigned int len;
int valid = 0;
if (dent_addr < min_addr)
goto bad_addr;
if (dent_addr > (unsigned long)high_memory - sizeof(struct dentry))
goto bad_addr;
if ((dent_addr & ~align_mask) != dent_addr)
goto bad_align;
if ((!kern_addr_valid(dent_addr)) || (!kern_addr_valid(dent_addr -1 +
sizeof(struct dentry))))
goto bad_addr;
/*
* Looks safe enough to dereference ...
*/
len = dentry->d_name.len;
if (len > SMB_MAXPATHLEN)
goto out;
/*
* Note: d_validate doesn't dereference the parent pointer ...
* just combines it with the name hash to find the hash chain.
*/
valid = d_validate(dentry, dentry->d_parent, dentry->d_name.hash, len);
out:
return valid;
bad_addr:
printk(KERN_ERR "smb_d_validate: invalid address %lx\n", dent_addr);
goto out;
bad_align:
printk(KERN_ERR "smb_d_validate: unaligned address %lx\n", dent_addr);
goto out;
}
/*
* dget, but require that fpos and parent matches what the dentry contains.
* dentry is not known to be a valid pointer at entry.
*/
struct dentry *
smb_dget_fpos(struct dentry *dentry, struct dentry *parent, unsigned long fpos)
{
struct dentry *dent = dentry;
struct list_head *next;
if (smb_d_validate(dent)) {
if (dent->d_parent == parent &&
(unsigned long)dent->d_fsdata == fpos) {
if (!dent->d_inode) {
dput(dent);
dent = NULL;
}
return dent;
}
dput(dent);
}
/* If a pointer is invalid, we search the dentry. */
spin_lock(&dcache_lock);
next = parent->d_subdirs.next;
while (next != &parent->d_subdirs) {
dent = list_entry(next, struct dentry, d_child);
if ((unsigned long)dent->d_fsdata == fpos) {
if (dent->d_inode)
dget_locked(dent);
else
dent = NULL;
goto out_unlock;
}
next = next->next;
}
dent = NULL;
out_unlock:
spin_unlock(&dcache_lock);
return dent;
}
/*
* Create dentry/inode for this file and add it to the dircache.
*/
int
smb_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
struct smb_cache_control *ctrl, struct qstr *qname,
struct smb_fattr *entry)
{
struct dentry *newdent, *dentry = filp->f_dentry;
struct inode *newino, *inode = dentry->d_inode;
struct smb_cache_control ctl = *ctrl;
int valid = 0;
ino_t ino = 0;
qname->hash = full_name_hash(qname->name, qname->len);
if (dentry->d_op && dentry->d_op->d_hash)
if (dentry->d_op->d_hash(dentry, qname) != 0)
goto end_advance;
newdent = d_lookup(dentry, qname);
if (!newdent) {
newdent = d_alloc(dentry, qname);
if (!newdent)
goto end_advance;
} else
memcpy((char *) newdent->d_name.name, qname->name,
newdent->d_name.len);
if (!newdent->d_inode) {
smb_renew_times(newdent);
entry->f_ino = iunique(inode->i_sb, 2);
newino = smb_iget(inode->i_sb, entry);
if (newino) {
smb_new_dentry(newdent);
d_add(newdent, newino);
}
} else
smb_set_inode_attr(newdent->d_inode, entry);
if (newdent->d_inode) {
ino = newdent->d_inode->i_ino;
newdent->d_fsdata = (void *) ctl.fpos;
smb_new_dentry(newdent);
}
if (ctl.idx >= SMB_DIRCACHE_SIZE) {
if (ctl.page) {
kunmap(ctl.page);
SetPageUptodate(ctl.page);
UnlockPage(ctl.page);
page_cache_release(ctl.page);
}
ctl.cache = NULL;
ctl.idx -= SMB_DIRCACHE_SIZE;
ctl.ofs += 1;
ctl.page = grab_cache_page(&inode->i_data, ctl.ofs);
if (ctl.page)
ctl.cache = kmap(ctl.page);
}
if (ctl.cache) {
ctl.cache->dentry[ctl.idx] = newdent;
valid = 1;
}
dput(newdent);
end_advance:
if (!valid)
ctl.valid = 0;
if (!ctl.filled && (ctl.fpos == filp->f_pos)) {
if (!ino)
ino = find_inode_number(dentry, qname);
if (!ino)
ino = iunique(inode->i_sb, 2);
ctl.filled = filldir(dirent, qname->name, qname->len,
filp->f_pos, ino, DT_UNKNOWN);
if (!ctl.filled)
filp->f_pos += 1;
}
ctl.fpos += 1;
ctl.idx += 1;
*ctrl = ctl;
return (ctl.valid || !ctl.filled);
}
|
