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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 | |
55 | const struct inode_operations vxfs_dir_inode_ops = { |
56 | .lookup = vxfs_lookup, |
57 | }; |
58 | |
59 | const struct file_operations vxfs_dir_operations = { |
60 | .readdir = vxfs_readdir, |
61 | }; |
62 | |
63 | |
64 | static inline u_long |
65 | dir_pages(struct inode *inode) |
66 | { |
67 | return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
68 | } |
69 | |
70 | static inline u_long |
71 | dir_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 | */ |
82 | static inline int |
83 | vxfs_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 | |
92 | static inline struct vxfs_direct * |
93 | vxfs_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 | */ |
112 | static struct vxfs_direct * |
113 | vxfs_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 | */ |
173 | static ino_t |
174 | vxfs_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 | */ |
204 | static struct dentry * |
205 | vxfs_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 = vxfs_iget(dip->i_sb, ino); |
217 | if (IS_ERR(ip)) { |
218 | unlock_kernel(); |
219 | return ERR_CAST(ip); |
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 | */ |
240 | static int |
241 | vxfs_readdir(struct file *fp, void *retp, filldir_t filler) |
242 | { |
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; |
248 | |
249 | lock_kernel(); |
250 | |
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 */ |
262 | } |
263 | |
264 | pos = fp->f_pos - 2; |
265 | |
266 | if (pos > VXFS_DIRROUND(ip->i_size)) { |
267 | unlock_kernel(); |
268 | return 0; |
269 | } |
270 | |
271 | npages = dir_pages(ip); |
272 | nblocks = dir_blocks(ip); |
273 | pblocks = VXFS_BLOCK_PER_PAGE(sbp); |
274 | |
275 | page = pos >> PAGE_CACHE_SHIFT; |
276 | offset = pos & ~PAGE_CACHE_MASK; |
277 | block = (u_long)(pos >> sbp->s_blocksize_bits) % pblocks; |
278 | |
279 | for (; page < npages; page++, block = 0) { |
280 | caddr_t kaddr; |
281 | struct page *pp; |
282 | |
283 | pp = vxfs_get_page(ip->i_mapping, page); |
284 | if (IS_ERR(pp)) |
285 | continue; |
286 | kaddr = (caddr_t)page_address(pp); |
287 | |
288 | for (; block <= nblocks && block <= pblocks; block++) { |
289 | caddr_t baddr, limit; |
290 | struct vxfs_dirblk *dbp; |
291 | struct vxfs_direct *de; |
292 | |
293 | baddr = kaddr + (block * bsize); |
294 | limit = baddr + bsize - VXFS_DIRLEN(1); |
295 | |
296 | dbp = (struct vxfs_dirblk *)baddr; |
297 | de = (struct vxfs_direct *) |
298 | (offset ? |
299 | (kaddr + offset) : |
300 | (baddr + VXFS_DIRBLKOV(dbp))); |
301 | |
302 | for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) { |
303 | int over; |
304 | |
305 | if (!de->d_reclen) |
306 | break; |
307 | if (!de->d_ino) |
308 | continue; |
309 | |
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; |
317 | } |
318 | } |
319 | offset = 0; |
320 | } |
321 | vxfs_put_page(pp); |
322 | offset = 0; |
323 | } |
324 | |
325 | done: |
326 | fp->f_pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2; |
327 | out: |
328 | unlock_kernel(); |
329 | return 0; |
330 | } |
331 |
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