Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[wrt350n-kernel.git] / fs / freevxfs / vxfs_lookup.c
blobaee049cb9f84782640d365a90156f423d2a37b46
1 /*
2 * Copyright (c) 2000-2001 Christoph Hellwig.
3 * All rights reserved.
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.
14 * Alternatively, this software may be distributed under the terms of the
15 * GNU General Public License ("GPL").
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.
31 * Veritas filesystem driver - lookup and other directory related code.
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>
41 #include "vxfs.h"
42 #include "vxfs_dir.h"
43 #include "vxfs_inode.h"
44 #include "vxfs_extern.h"
47 * Number of VxFS blocks per page.
49 #define VXFS_BLOCK_PER_PAGE(sbp) ((PAGE_CACHE_SIZE / (sbp)->s_blocksize))
52 static struct dentry * vxfs_lookup(struct inode *, struct dentry *, struct nameidata *);
53 static int vxfs_readdir(struct file *, void *, filldir_t);
55 const struct inode_operations vxfs_dir_inode_ops = {
56 .lookup = vxfs_lookup,
59 const struct file_operations vxfs_dir_operations = {
60 .readdir = vxfs_readdir,
64 static inline u_long
65 dir_pages(struct inode *inode)
67 return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
70 static inline u_long
71 dir_blocks(struct inode *ip)
73 u_long bsize = ip->i_sb->s_blocksize;
74 return (ip->i_size + bsize - 1) & ~(bsize - 1);
78 * NOTE! unlike strncmp, vxfs_match returns 1 for success, 0 for failure.
80 * len <= VXFS_NAMELEN and de != NULL are guaranteed by caller.
82 static inline int
83 vxfs_match(int len, const char * const name, struct vxfs_direct *de)
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);
92 static inline struct vxfs_direct *
93 vxfs_next_entry(struct vxfs_direct *de)
95 return ((struct vxfs_direct *)((char*)de + de->d_reclen));
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
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.
109 * Returns:
110 * The wanted direct on success, else a NULL pointer.
112 static struct vxfs_direct *
113 vxfs_find_entry(struct inode *ip, struct dentry *dp, struct page **ppp)
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;
120 npages = dir_pages(ip);
121 nblocks = dir_blocks(ip);
122 pblocks = VXFS_BLOCK_PER_PAGE(ip->i_sb);
124 for (page = 0; page < npages; page++) {
125 caddr_t kaddr;
126 struct page *pp;
128 pp = vxfs_get_page(ip->i_mapping, page);
129 if (IS_ERR(pp))
130 continue;
131 kaddr = (caddr_t)page_address(pp);
133 for (block = 0; block <= nblocks && block <= pblocks; block++) {
134 caddr_t baddr, limit;
135 struct vxfs_dirblk *dbp;
136 struct vxfs_direct *de;
138 baddr = kaddr + (block * bsize);
139 limit = baddr + bsize - VXFS_DIRLEN(1);
141 dbp = (struct vxfs_dirblk *)baddr;
142 de = (struct vxfs_direct *)(baddr + VXFS_DIRBLKOV(dbp));
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);
155 vxfs_put_page(pp);
158 return NULL;
162 * vxfs_inode_by_name - find inode number for dentry
163 * @dip: directory to search in
164 * @dp: dentry we seach for
166 * Description:
167 * vxfs_inode_by_name finds out the inode number of
168 * the path component described by @dp in @dip.
170 * Returns:
171 * The wanted inode number on success, else Zero.
173 static ino_t
174 vxfs_inode_by_name(struct inode *dip, struct dentry *dp)
176 struct vxfs_direct *de;
177 struct page *pp;
178 ino_t ino = 0;
180 de = vxfs_find_entry(dip, dp, &pp);
181 if (de) {
182 ino = de->d_ino;
183 kunmap(pp);
184 page_cache_release(pp);
187 return (ino);
191 * vxfs_lookup - lookup pathname component
192 * @dip: dir in which we lookup
193 * @dp: dentry we lookup
194 * @nd: lookup nameidata
196 * Description:
197 * vxfs_lookup tries to lookup the pathname component described
198 * by @dp in @dip.
200 * Returns:
201 * A NULL-pointer on success, else an negative error code encoded
202 * in the return pointer.
204 static struct dentry *
205 vxfs_lookup(struct inode *dip, struct dentry *dp, struct nameidata *nd)
207 struct inode *ip = NULL;
208 ino_t ino;
210 if (dp->d_name.len > VXFS_NAMELEN)
211 return ERR_PTR(-ENAMETOOLONG);
213 lock_kernel();
214 ino = vxfs_inode_by_name(dip, dp);
215 if (ino) {
216 ip = vxfs_iget(dip->i_sb, ino);
217 if (IS_ERR(ip)) {
218 unlock_kernel();
219 return ERR_CAST(ip);
222 unlock_kernel();
223 d_add(dp, ip);
224 return NULL;
228 * vxfs_readdir - read a directory
229 * @fp: the directory to read
230 * @retp: return buffer
231 * @filler: filldir callback
233 * Description:
234 * vxfs_readdir fills @retp with directory entries from @fp
235 * using the VFS supplied callback @filler.
237 * Returns:
238 * Zero.
240 static int
241 vxfs_readdir(struct file *fp, void *retp, filldir_t filler)
243 struct inode *ip = fp->f_path.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;
249 lock_kernel();
251 switch ((long)fp->f_pos) {
252 case 0:
253 if (filler(retp, ".", 1, fp->f_pos, ip->i_ino, DT_DIR) < 0)
254 goto out;
255 fp->f_pos++;
256 /* fallthrough */
257 case 1:
258 if (filler(retp, "..", 2, fp->f_pos, VXFS_INO(ip)->vii_dotdot, DT_DIR) < 0)
259 goto out;
260 fp->f_pos++;
261 /* fallthrough */
264 pos = fp->f_pos - 2;
266 if (pos > VXFS_DIRROUND(ip->i_size)) {
267 unlock_kernel();
268 return 0;
271 npages = dir_pages(ip);
272 nblocks = dir_blocks(ip);
273 pblocks = VXFS_BLOCK_PER_PAGE(sbp);
275 page = pos >> PAGE_CACHE_SHIFT;
276 offset = pos & ~PAGE_CACHE_MASK;
277 block = (u_long)(pos >> sbp->s_blocksize_bits) % pblocks;
279 for (; page < npages; page++, block = 0) {
280 caddr_t kaddr;
281 struct page *pp;
283 pp = vxfs_get_page(ip->i_mapping, page);
284 if (IS_ERR(pp))
285 continue;
286 kaddr = (caddr_t)page_address(pp);
288 for (; block <= nblocks && block <= pblocks; block++) {
289 caddr_t baddr, limit;
290 struct vxfs_dirblk *dbp;
291 struct vxfs_direct *de;
293 baddr = kaddr + (block * bsize);
294 limit = baddr + bsize - VXFS_DIRLEN(1);
296 dbp = (struct vxfs_dirblk *)baddr;
297 de = (struct vxfs_direct *)
298 (offset ?
299 (kaddr + offset) :
300 (baddr + VXFS_DIRBLKOV(dbp)));
302 for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
303 int over;
305 if (!de->d_reclen)
306 break;
307 if (!de->d_ino)
308 continue;
310 offset = (caddr_t)de - kaddr;
311 over = filler(retp, de->d_name, de->d_namelen,
312 ((page << PAGE_CACHE_SHIFT) | offset) + 2,
313 de->d_ino, DT_UNKNOWN);
314 if (over) {
315 vxfs_put_page(pp);
316 goto done;
319 offset = 0;
321 vxfs_put_page(pp);
322 offset = 0;
325 done:
326 fp->f_pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2;
327 out:
328 unlock_kernel();
329 return 0;