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