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1da177e4 LT |
1 | /* |
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 | ||
52 | static struct dentry * vxfs_lookup(struct inode *, struct dentry *, struct nameidata *); | |
53 | static int vxfs_readdir(struct file *, void *, filldir_t); | |
54 | ||
754661f1 | 55 | const struct inode_operations vxfs_dir_inode_ops = { |
1da177e4 LT |
56 | .lookup = vxfs_lookup, |
57 | }; | |
58 | ||
4b6f5d20 | 59 | const struct file_operations vxfs_dir_operations = { |
ca572727 B |
60 | .llseek = generic_file_llseek, |
61 | .read = generic_read_dir, | |
1da177e4 LT |
62 | .readdir = vxfs_readdir, |
63 | }; | |
64 | ||
65 | ||
8cb681b9 | 66 | static inline u_long |
1da177e4 LT |
67 | dir_pages(struct inode *inode) |
68 | { | |
69 | return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
70 | } | |
71 | ||
8cb681b9 | 72 | static inline u_long |
1da177e4 LT |
73 | dir_blocks(struct inode *ip) |
74 | { | |
75 | u_long bsize = ip->i_sb->s_blocksize; | |
76 | return (ip->i_size + bsize - 1) & ~(bsize - 1); | |
77 | } | |
78 | ||
79 | /* | |
80 | * NOTE! unlike strncmp, vxfs_match returns 1 for success, 0 for failure. | |
81 | * | |
82 | * len <= VXFS_NAMELEN and de != NULL are guaranteed by caller. | |
83 | */ | |
8cb681b9 | 84 | static inline int |
1da177e4 LT |
85 | vxfs_match(int len, const char * const name, struct vxfs_direct *de) |
86 | { | |
87 | if (len != de->d_namelen) | |
88 | return 0; | |
89 | if (!de->d_ino) | |
90 | return 0; | |
91 | return !memcmp(name, de->d_name, len); | |
92 | } | |
93 | ||
8cb681b9 | 94 | static inline struct vxfs_direct * |
1da177e4 LT |
95 | vxfs_next_entry(struct vxfs_direct *de) |
96 | { | |
97 | return ((struct vxfs_direct *)((char*)de + de->d_reclen)); | |
98 | } | |
99 | ||
100 | /** | |
101 | * vxfs_find_entry - find a mathing directory entry for a dentry | |
102 | * @ip: directory inode | |
103 | * @dp: dentry for which we want to find a direct | |
104 | * @ppp: gets filled with the page the return value sits in | |
105 | * | |
106 | * Description: | |
107 | * vxfs_find_entry finds a &struct vxfs_direct for the VFS directory | |
108 | * cache entry @dp. @ppp will be filled with the page the return | |
109 | * value resides in. | |
110 | * | |
111 | * Returns: | |
112 | * The wanted direct on success, else a NULL pointer. | |
113 | */ | |
114 | static struct vxfs_direct * | |
115 | vxfs_find_entry(struct inode *ip, struct dentry *dp, struct page **ppp) | |
116 | { | |
117 | u_long npages, page, nblocks, pblocks, block; | |
118 | u_long bsize = ip->i_sb->s_blocksize; | |
119 | const char *name = dp->d_name.name; | |
120 | int namelen = dp->d_name.len; | |
121 | ||
122 | npages = dir_pages(ip); | |
123 | nblocks = dir_blocks(ip); | |
124 | pblocks = VXFS_BLOCK_PER_PAGE(ip->i_sb); | |
125 | ||
126 | for (page = 0; page < npages; page++) { | |
127 | caddr_t kaddr; | |
128 | struct page *pp; | |
129 | ||
130 | pp = vxfs_get_page(ip->i_mapping, page); | |
131 | if (IS_ERR(pp)) | |
132 | continue; | |
133 | kaddr = (caddr_t)page_address(pp); | |
134 | ||
135 | for (block = 0; block <= nblocks && block <= pblocks; block++) { | |
136 | caddr_t baddr, limit; | |
137 | struct vxfs_dirblk *dbp; | |
138 | struct vxfs_direct *de; | |
139 | ||
140 | baddr = kaddr + (block * bsize); | |
141 | limit = baddr + bsize - VXFS_DIRLEN(1); | |
142 | ||
143 | dbp = (struct vxfs_dirblk *)baddr; | |
144 | de = (struct vxfs_direct *)(baddr + VXFS_DIRBLKOV(dbp)); | |
145 | ||
146 | for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) { | |
147 | if (!de->d_reclen) | |
148 | break; | |
149 | if (!de->d_ino) | |
150 | continue; | |
151 | if (vxfs_match(namelen, name, de)) { | |
152 | *ppp = pp; | |
153 | return (de); | |
154 | } | |
155 | } | |
156 | } | |
157 | vxfs_put_page(pp); | |
158 | } | |
159 | ||
160 | return NULL; | |
161 | } | |
162 | ||
163 | /** | |
164 | * vxfs_inode_by_name - find inode number for dentry | |
165 | * @dip: directory to search in | |
166 | * @dp: dentry we seach for | |
167 | * | |
168 | * Description: | |
169 | * vxfs_inode_by_name finds out the inode number of | |
170 | * the path component described by @dp in @dip. | |
171 | * | |
172 | * Returns: | |
173 | * The wanted inode number on success, else Zero. | |
174 | */ | |
175 | static ino_t | |
176 | vxfs_inode_by_name(struct inode *dip, struct dentry *dp) | |
177 | { | |
178 | struct vxfs_direct *de; | |
179 | struct page *pp; | |
180 | ino_t ino = 0; | |
181 | ||
182 | de = vxfs_find_entry(dip, dp, &pp); | |
183 | if (de) { | |
184 | ino = de->d_ino; | |
185 | kunmap(pp); | |
186 | page_cache_release(pp); | |
187 | } | |
188 | ||
189 | return (ino); | |
190 | } | |
191 | ||
192 | /** | |
193 | * vxfs_lookup - lookup pathname component | |
194 | * @dip: dir in which we lookup | |
195 | * @dp: dentry we lookup | |
196 | * @nd: lookup nameidata | |
197 | * | |
198 | * Description: | |
199 | * vxfs_lookup tries to lookup the pathname component described | |
200 | * by @dp in @dip. | |
201 | * | |
202 | * Returns: | |
203 | * A NULL-pointer on success, else an negative error code encoded | |
204 | * in the return pointer. | |
205 | */ | |
206 | static struct dentry * | |
207 | vxfs_lookup(struct inode *dip, struct dentry *dp, struct nameidata *nd) | |
208 | { | |
209 | struct inode *ip = NULL; | |
210 | ino_t ino; | |
211 | ||
212 | if (dp->d_name.len > VXFS_NAMELEN) | |
213 | return ERR_PTR(-ENAMETOOLONG); | |
214 | ||
215 | lock_kernel(); | |
216 | ino = vxfs_inode_by_name(dip, dp); | |
217 | if (ino) { | |
d0b07948 DH |
218 | ip = vxfs_iget(dip->i_sb, ino); |
219 | if (IS_ERR(ip)) { | |
1da177e4 | 220 | unlock_kernel(); |
d0b07948 | 221 | return ERR_CAST(ip); |
1da177e4 LT |
222 | } |
223 | } | |
224 | unlock_kernel(); | |
225 | d_add(dp, ip); | |
226 | return NULL; | |
227 | } | |
228 | ||
229 | /** | |
230 | * vxfs_readdir - read a directory | |
231 | * @fp: the directory to read | |
232 | * @retp: return buffer | |
233 | * @filler: filldir callback | |
234 | * | |
235 | * Description: | |
236 | * vxfs_readdir fills @retp with directory entries from @fp | |
237 | * using the VFS supplied callback @filler. | |
238 | * | |
239 | * Returns: | |
240 | * Zero. | |
241 | */ | |
242 | static int | |
243 | vxfs_readdir(struct file *fp, void *retp, filldir_t filler) | |
244 | { | |
6a90cd24 | 245 | struct inode *ip = fp->f_path.dentry->d_inode; |
1da177e4 LT |
246 | struct super_block *sbp = ip->i_sb; |
247 | u_long bsize = sbp->s_blocksize; | |
248 | u_long page, npages, block, pblocks, nblocks, offset; | |
249 | loff_t pos; | |
250 | ||
bc65ac6a JT |
251 | lock_kernel(); |
252 | ||
1da177e4 LT |
253 | switch ((long)fp->f_pos) { |
254 | case 0: | |
255 | if (filler(retp, ".", 1, fp->f_pos, ip->i_ino, DT_DIR) < 0) | |
256 | goto out; | |
257 | fp->f_pos++; | |
258 | /* fallthrough */ | |
259 | case 1: | |
260 | if (filler(retp, "..", 2, fp->f_pos, VXFS_INO(ip)->vii_dotdot, DT_DIR) < 0) | |
261 | goto out; | |
262 | fp->f_pos++; | |
263 | /* fallthrough */ | |
264 | } | |
265 | ||
266 | pos = fp->f_pos - 2; | |
267 | ||
268 | if (pos > VXFS_DIRROUND(ip->i_size)) { | |
269 | unlock_kernel(); | |
270 | return 0; | |
271 | } | |
272 | ||
273 | npages = dir_pages(ip); | |
274 | nblocks = dir_blocks(ip); | |
275 | pblocks = VXFS_BLOCK_PER_PAGE(sbp); | |
276 | ||
277 | page = pos >> PAGE_CACHE_SHIFT; | |
278 | offset = pos & ~PAGE_CACHE_MASK; | |
279 | block = (u_long)(pos >> sbp->s_blocksize_bits) % pblocks; | |
280 | ||
281 | for (; page < npages; page++, block = 0) { | |
282 | caddr_t kaddr; | |
283 | struct page *pp; | |
284 | ||
285 | pp = vxfs_get_page(ip->i_mapping, page); | |
286 | if (IS_ERR(pp)) | |
287 | continue; | |
288 | kaddr = (caddr_t)page_address(pp); | |
289 | ||
290 | for (; block <= nblocks && block <= pblocks; block++) { | |
291 | caddr_t baddr, limit; | |
292 | struct vxfs_dirblk *dbp; | |
293 | struct vxfs_direct *de; | |
294 | ||
295 | baddr = kaddr + (block * bsize); | |
296 | limit = baddr + bsize - VXFS_DIRLEN(1); | |
297 | ||
298 | dbp = (struct vxfs_dirblk *)baddr; | |
299 | de = (struct vxfs_direct *) | |
300 | (offset ? | |
301 | (kaddr + offset) : | |
302 | (baddr + VXFS_DIRBLKOV(dbp))); | |
303 | ||
304 | for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) { | |
305 | int over; | |
306 | ||
307 | if (!de->d_reclen) | |
308 | break; | |
309 | if (!de->d_ino) | |
310 | continue; | |
311 | ||
312 | offset = (caddr_t)de - kaddr; | |
313 | over = filler(retp, de->d_name, de->d_namelen, | |
314 | ((page << PAGE_CACHE_SHIFT) | offset) + 2, | |
315 | de->d_ino, DT_UNKNOWN); | |
316 | if (over) { | |
317 | vxfs_put_page(pp); | |
318 | goto done; | |
319 | } | |
320 | } | |
321 | offset = 0; | |
322 | } | |
323 | vxfs_put_page(pp); | |
324 | offset = 0; | |
325 | } | |
326 | ||
327 | done: | |
328 | fp->f_pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2; | |
329 | out: | |
330 | unlock_kernel(); | |
331 | return 0; | |
332 | } |