blob: 554eb455722cbb3812837d3bc1b7b64290ebcc30 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (c) 2000-2001 Christoph Hellwig.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions, and the following disclaimer,
10 * without modification.
11 * 2. The name of the author may not be used to endorse or promote products
12 * derived from this software without specific prior written permission.
13 *
14 * Alternatively, this software may be distributed under the terms of the
15 * GNU General Public License ("GPL").
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
21 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30/*
31 * Veritas filesystem driver - lookup and other directory related code.
32 */
33#include <linux/fs.h>
34#include <linux/time.h>
35#include <linux/mm.h>
36#include <linux/highmem.h>
37#include <linux/kernel.h>
38#include <linux/pagemap.h>
39#include <linux/smp_lock.h>
40
41#include "vxfs.h"
42#include "vxfs_dir.h"
43#include "vxfs_inode.h"
44#include "vxfs_extern.h"
45
46/*
47 * Number of VxFS blocks per page.
48 */
49#define VXFS_BLOCK_PER_PAGE(sbp) ((PAGE_CACHE_SIZE / (sbp)->s_blocksize))
50
51
52static struct dentry * vxfs_lookup(struct inode *, struct dentry *, struct nameidata *);
53static int vxfs_readdir(struct file *, void *, filldir_t);
54
55struct inode_operations vxfs_dir_inode_ops = {
56 .lookup = vxfs_lookup,
57};
58
59struct file_operations vxfs_dir_operations = {
60 .readdir = vxfs_readdir,
61};
62
63
Pekka Enberg8cb681b2005-06-30 02:59:05 -070064static inline u_long
Linus Torvalds1da177e2005-04-16 15:20:36 -070065dir_pages(struct inode *inode)
66{
67 return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
68}
69
Pekka Enberg8cb681b2005-06-30 02:59:05 -070070static inline u_long
Linus Torvalds1da177e2005-04-16 15:20:36 -070071dir_blocks(struct inode *ip)
72{
73 u_long bsize = ip->i_sb->s_blocksize;
74 return (ip->i_size + bsize - 1) & ~(bsize - 1);
75}
76
77/*
78 * NOTE! unlike strncmp, vxfs_match returns 1 for success, 0 for failure.
79 *
80 * len <= VXFS_NAMELEN and de != NULL are guaranteed by caller.
81 */
Pekka Enberg8cb681b2005-06-30 02:59:05 -070082static inline int
Linus Torvalds1da177e2005-04-16 15:20:36 -070083vxfs_match(int len, const char * const name, struct vxfs_direct *de)
84{
85 if (len != de->d_namelen)
86 return 0;
87 if (!de->d_ino)
88 return 0;
89 return !memcmp(name, de->d_name, len);
90}
91
Pekka Enberg8cb681b2005-06-30 02:59:05 -070092static inline struct vxfs_direct *
Linus Torvalds1da177e2005-04-16 15:20:36 -070093vxfs_next_entry(struct vxfs_direct *de)
94{
95 return ((struct vxfs_direct *)((char*)de + de->d_reclen));
96}
97
98/**
99 * vxfs_find_entry - find a mathing directory entry for a dentry
100 * @ip: directory inode
101 * @dp: dentry for which we want to find a direct
102 * @ppp: gets filled with the page the return value sits in
103 *
104 * Description:
105 * vxfs_find_entry finds a &struct vxfs_direct for the VFS directory
106 * cache entry @dp. @ppp will be filled with the page the return
107 * value resides in.
108 *
109 * Returns:
110 * The wanted direct on success, else a NULL pointer.
111 */
112static struct vxfs_direct *
113vxfs_find_entry(struct inode *ip, struct dentry *dp, struct page **ppp)
114{
115 u_long npages, page, nblocks, pblocks, block;
116 u_long bsize = ip->i_sb->s_blocksize;
117 const char *name = dp->d_name.name;
118 int namelen = dp->d_name.len;
119
120 npages = dir_pages(ip);
121 nblocks = dir_blocks(ip);
122 pblocks = VXFS_BLOCK_PER_PAGE(ip->i_sb);
123
124 for (page = 0; page < npages; page++) {
125 caddr_t kaddr;
126 struct page *pp;
127
128 pp = vxfs_get_page(ip->i_mapping, page);
129 if (IS_ERR(pp))
130 continue;
131 kaddr = (caddr_t)page_address(pp);
132
133 for (block = 0; block <= nblocks && block <= pblocks; block++) {
134 caddr_t baddr, limit;
135 struct vxfs_dirblk *dbp;
136 struct vxfs_direct *de;
137
138 baddr = kaddr + (block * bsize);
139 limit = baddr + bsize - VXFS_DIRLEN(1);
140
141 dbp = (struct vxfs_dirblk *)baddr;
142 de = (struct vxfs_direct *)(baddr + VXFS_DIRBLKOV(dbp));
143
144 for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
145 if (!de->d_reclen)
146 break;
147 if (!de->d_ino)
148 continue;
149 if (vxfs_match(namelen, name, de)) {
150 *ppp = pp;
151 return (de);
152 }
153 }
154 }
155 vxfs_put_page(pp);
156 }
157
158 return NULL;
159}
160
161/**
162 * vxfs_inode_by_name - find inode number for dentry
163 * @dip: directory to search in
164 * @dp: dentry we seach for
165 *
166 * Description:
167 * vxfs_inode_by_name finds out the inode number of
168 * the path component described by @dp in @dip.
169 *
170 * Returns:
171 * The wanted inode number on success, else Zero.
172 */
173static ino_t
174vxfs_inode_by_name(struct inode *dip, struct dentry *dp)
175{
176 struct vxfs_direct *de;
177 struct page *pp;
178 ino_t ino = 0;
179
180 de = vxfs_find_entry(dip, dp, &pp);
181 if (de) {
182 ino = de->d_ino;
183 kunmap(pp);
184 page_cache_release(pp);
185 }
186
187 return (ino);
188}
189
190/**
191 * vxfs_lookup - lookup pathname component
192 * @dip: dir in which we lookup
193 * @dp: dentry we lookup
194 * @nd: lookup nameidata
195 *
196 * Description:
197 * vxfs_lookup tries to lookup the pathname component described
198 * by @dp in @dip.
199 *
200 * Returns:
201 * A NULL-pointer on success, else an negative error code encoded
202 * in the return pointer.
203 */
204static struct dentry *
205vxfs_lookup(struct inode *dip, struct dentry *dp, struct nameidata *nd)
206{
207 struct inode *ip = NULL;
208 ino_t ino;
209
210 if (dp->d_name.len > VXFS_NAMELEN)
211 return ERR_PTR(-ENAMETOOLONG);
212
213 lock_kernel();
214 ino = vxfs_inode_by_name(dip, dp);
215 if (ino) {
216 ip = iget(dip->i_sb, ino);
217 if (!ip) {
218 unlock_kernel();
219 return ERR_PTR(-EACCES);
220 }
221 }
222 unlock_kernel();
223 d_add(dp, ip);
224 return NULL;
225}
226
227/**
228 * vxfs_readdir - read a directory
229 * @fp: the directory to read
230 * @retp: return buffer
231 * @filler: filldir callback
232 *
233 * Description:
234 * vxfs_readdir fills @retp with directory entries from @fp
235 * using the VFS supplied callback @filler.
236 *
237 * Returns:
238 * Zero.
239 */
240static int
241vxfs_readdir(struct file *fp, void *retp, filldir_t filler)
242{
243 struct inode *ip = fp->f_dentry->d_inode;
244 struct super_block *sbp = ip->i_sb;
245 u_long bsize = sbp->s_blocksize;
246 u_long page, npages, block, pblocks, nblocks, offset;
247 loff_t pos;
248
249 switch ((long)fp->f_pos) {
250 case 0:
251 if (filler(retp, ".", 1, fp->f_pos, ip->i_ino, DT_DIR) < 0)
252 goto out;
253 fp->f_pos++;
254 /* fallthrough */
255 case 1:
256 if (filler(retp, "..", 2, fp->f_pos, VXFS_INO(ip)->vii_dotdot, DT_DIR) < 0)
257 goto out;
258 fp->f_pos++;
259 /* fallthrough */
260 }
261
262 pos = fp->f_pos - 2;
263
264 if (pos > VXFS_DIRROUND(ip->i_size)) {
265 unlock_kernel();
266 return 0;
267 }
268
269 npages = dir_pages(ip);
270 nblocks = dir_blocks(ip);
271 pblocks = VXFS_BLOCK_PER_PAGE(sbp);
272
273 page = pos >> PAGE_CACHE_SHIFT;
274 offset = pos & ~PAGE_CACHE_MASK;
275 block = (u_long)(pos >> sbp->s_blocksize_bits) % pblocks;
276
277 for (; page < npages; page++, block = 0) {
278 caddr_t kaddr;
279 struct page *pp;
280
281 pp = vxfs_get_page(ip->i_mapping, page);
282 if (IS_ERR(pp))
283 continue;
284 kaddr = (caddr_t)page_address(pp);
285
286 for (; block <= nblocks && block <= pblocks; block++) {
287 caddr_t baddr, limit;
288 struct vxfs_dirblk *dbp;
289 struct vxfs_direct *de;
290
291 baddr = kaddr + (block * bsize);
292 limit = baddr + bsize - VXFS_DIRLEN(1);
293
294 dbp = (struct vxfs_dirblk *)baddr;
295 de = (struct vxfs_direct *)
296 (offset ?
297 (kaddr + offset) :
298 (baddr + VXFS_DIRBLKOV(dbp)));
299
300 for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
301 int over;
302
303 if (!de->d_reclen)
304 break;
305 if (!de->d_ino)
306 continue;
307
308 offset = (caddr_t)de - kaddr;
309 over = filler(retp, de->d_name, de->d_namelen,
310 ((page << PAGE_CACHE_SHIFT) | offset) + 2,
311 de->d_ino, DT_UNKNOWN);
312 if (over) {
313 vxfs_put_page(pp);
314 goto done;
315 }
316 }
317 offset = 0;
318 }
319 vxfs_put_page(pp);
320 offset = 0;
321 }
322
323done:
324 fp->f_pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2;
325out:
326 unlock_kernel();
327 return 0;
328}