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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> | |
1da177e4 LT |
39 | |
40 | #include "vxfs.h" | |
41 | #include "vxfs_dir.h" | |
42 | #include "vxfs_inode.h" | |
43 | #include "vxfs_extern.h" | |
44 | ||
45 | /* | |
46 | * Number of VxFS blocks per page. | |
47 | */ | |
48 | #define VXFS_BLOCK_PER_PAGE(sbp) ((PAGE_CACHE_SIZE / (sbp)->s_blocksize)) | |
49 | ||
50 | ||
00cd8dd3 | 51 | static struct dentry * vxfs_lookup(struct inode *, struct dentry *, unsigned int); |
9b5d5a17 | 52 | static int vxfs_readdir(struct file *, struct dir_context *); |
1da177e4 | 53 | |
754661f1 | 54 | const struct inode_operations vxfs_dir_inode_ops = { |
1da177e4 LT |
55 | .lookup = vxfs_lookup, |
56 | }; | |
57 | ||
4b6f5d20 | 58 | const struct file_operations vxfs_dir_operations = { |
ca572727 B |
59 | .llseek = generic_file_llseek, |
60 | .read = generic_read_dir, | |
9b5d5a17 | 61 | .iterate = vxfs_readdir, |
1da177e4 LT |
62 | }; |
63 | ||
8cb681b9 | 64 | static inline u_long |
1da177e4 LT |
65 | dir_blocks(struct inode *ip) |
66 | { | |
67 | u_long bsize = ip->i_sb->s_blocksize; | |
68 | return (ip->i_size + bsize - 1) & ~(bsize - 1); | |
69 | } | |
70 | ||
71 | /* | |
72 | * NOTE! unlike strncmp, vxfs_match returns 1 for success, 0 for failure. | |
73 | * | |
74 | * len <= VXFS_NAMELEN and de != NULL are guaranteed by caller. | |
75 | */ | |
8cb681b9 | 76 | static inline int |
1da177e4 LT |
77 | vxfs_match(int len, const char * const name, struct vxfs_direct *de) |
78 | { | |
79 | if (len != de->d_namelen) | |
80 | return 0; | |
81 | if (!de->d_ino) | |
82 | return 0; | |
83 | return !memcmp(name, de->d_name, len); | |
84 | } | |
85 | ||
8cb681b9 | 86 | static inline struct vxfs_direct * |
1da177e4 LT |
87 | vxfs_next_entry(struct vxfs_direct *de) |
88 | { | |
89 | return ((struct vxfs_direct *)((char*)de + de->d_reclen)); | |
90 | } | |
91 | ||
92 | /** | |
93 | * vxfs_find_entry - find a mathing directory entry for a dentry | |
94 | * @ip: directory inode | |
95 | * @dp: dentry for which we want to find a direct | |
96 | * @ppp: gets filled with the page the return value sits in | |
97 | * | |
98 | * Description: | |
99 | * vxfs_find_entry finds a &struct vxfs_direct for the VFS directory | |
100 | * cache entry @dp. @ppp will be filled with the page the return | |
101 | * value resides in. | |
102 | * | |
103 | * Returns: | |
104 | * The wanted direct on success, else a NULL pointer. | |
105 | */ | |
106 | static struct vxfs_direct * | |
107 | vxfs_find_entry(struct inode *ip, struct dentry *dp, struct page **ppp) | |
108 | { | |
109 | u_long npages, page, nblocks, pblocks, block; | |
110 | u_long bsize = ip->i_sb->s_blocksize; | |
111 | const char *name = dp->d_name.name; | |
112 | int namelen = dp->d_name.len; | |
113 | ||
114 | npages = dir_pages(ip); | |
115 | nblocks = dir_blocks(ip); | |
116 | pblocks = VXFS_BLOCK_PER_PAGE(ip->i_sb); | |
117 | ||
118 | for (page = 0; page < npages; page++) { | |
119 | caddr_t kaddr; | |
120 | struct page *pp; | |
121 | ||
122 | pp = vxfs_get_page(ip->i_mapping, page); | |
123 | if (IS_ERR(pp)) | |
124 | continue; | |
125 | kaddr = (caddr_t)page_address(pp); | |
126 | ||
127 | for (block = 0; block <= nblocks && block <= pblocks; block++) { | |
128 | caddr_t baddr, limit; | |
129 | struct vxfs_dirblk *dbp; | |
130 | struct vxfs_direct *de; | |
131 | ||
132 | baddr = kaddr + (block * bsize); | |
133 | limit = baddr + bsize - VXFS_DIRLEN(1); | |
134 | ||
135 | dbp = (struct vxfs_dirblk *)baddr; | |
136 | de = (struct vxfs_direct *)(baddr + VXFS_DIRBLKOV(dbp)); | |
137 | ||
138 | for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) { | |
139 | if (!de->d_reclen) | |
140 | break; | |
141 | if (!de->d_ino) | |
142 | continue; | |
143 | if (vxfs_match(namelen, name, de)) { | |
144 | *ppp = pp; | |
145 | return (de); | |
146 | } | |
147 | } | |
148 | } | |
149 | vxfs_put_page(pp); | |
150 | } | |
151 | ||
152 | return NULL; | |
153 | } | |
154 | ||
155 | /** | |
156 | * vxfs_inode_by_name - find inode number for dentry | |
157 | * @dip: directory to search in | |
25985edc | 158 | * @dp: dentry we search for |
1da177e4 LT |
159 | * |
160 | * Description: | |
161 | * vxfs_inode_by_name finds out the inode number of | |
162 | * the path component described by @dp in @dip. | |
163 | * | |
164 | * Returns: | |
165 | * The wanted inode number on success, else Zero. | |
166 | */ | |
167 | static ino_t | |
168 | vxfs_inode_by_name(struct inode *dip, struct dentry *dp) | |
169 | { | |
170 | struct vxfs_direct *de; | |
171 | struct page *pp; | |
172 | ino_t ino = 0; | |
173 | ||
174 | de = vxfs_find_entry(dip, dp, &pp); | |
175 | if (de) { | |
176 | ino = de->d_ino; | |
177 | kunmap(pp); | |
178 | page_cache_release(pp); | |
179 | } | |
180 | ||
181 | return (ino); | |
182 | } | |
183 | ||
184 | /** | |
185 | * vxfs_lookup - lookup pathname component | |
186 | * @dip: dir in which we lookup | |
187 | * @dp: dentry we lookup | |
ddae82d8 | 188 | * @flags: lookup flags |
1da177e4 LT |
189 | * |
190 | * Description: | |
191 | * vxfs_lookup tries to lookup the pathname component described | |
192 | * by @dp in @dip. | |
193 | * | |
194 | * Returns: | |
eaf593c3 | 195 | * A NULL-pointer on success, else a negative error code encoded |
1da177e4 LT |
196 | * in the return pointer. |
197 | */ | |
198 | static struct dentry * | |
00cd8dd3 | 199 | vxfs_lookup(struct inode *dip, struct dentry *dp, unsigned int flags) |
1da177e4 LT |
200 | { |
201 | struct inode *ip = NULL; | |
202 | ino_t ino; | |
203 | ||
204 | if (dp->d_name.len > VXFS_NAMELEN) | |
205 | return ERR_PTR(-ENAMETOOLONG); | |
206 | ||
1da177e4 LT |
207 | ino = vxfs_inode_by_name(dip, dp); |
208 | if (ino) { | |
d0b07948 | 209 | ip = vxfs_iget(dip->i_sb, ino); |
6d7bccc2 | 210 | if (IS_ERR(ip)) |
d0b07948 | 211 | return ERR_CAST(ip); |
1da177e4 | 212 | } |
1da177e4 LT |
213 | d_add(dp, ip); |
214 | return NULL; | |
215 | } | |
216 | ||
217 | /** | |
218 | * vxfs_readdir - read a directory | |
219 | * @fp: the directory to read | |
220 | * @retp: return buffer | |
221 | * @filler: filldir callback | |
222 | * | |
223 | * Description: | |
224 | * vxfs_readdir fills @retp with directory entries from @fp | |
225 | * using the VFS supplied callback @filler. | |
226 | * | |
227 | * Returns: | |
228 | * Zero. | |
229 | */ | |
230 | static int | |
9b5d5a17 | 231 | vxfs_readdir(struct file *fp, struct dir_context *ctx) |
1da177e4 | 232 | { |
496ad9aa | 233 | struct inode *ip = file_inode(fp); |
1da177e4 LT |
234 | struct super_block *sbp = ip->i_sb; |
235 | u_long bsize = sbp->s_blocksize; | |
236 | u_long page, npages, block, pblocks, nblocks, offset; | |
237 | loff_t pos; | |
238 | ||
9b5d5a17 AV |
239 | if (ctx->pos == 0) { |
240 | if (!dir_emit_dot(fp, ctx)) | |
241 | return 0; | |
242 | ctx->pos = 1; | |
1da177e4 | 243 | } |
9b5d5a17 AV |
244 | if (ctx->pos == 1) { |
245 | if (!dir_emit(ctx, "..", 2, VXFS_INO(ip)->vii_dotdot, DT_DIR)) | |
246 | return 0; | |
247 | ctx->pos = 2; | |
248 | } | |
249 | pos = ctx->pos - 2; | |
1da177e4 | 250 | |
6d7bccc2 | 251 | if (pos > VXFS_DIRROUND(ip->i_size)) |
1da177e4 | 252 | return 0; |
1da177e4 LT |
253 | |
254 | npages = dir_pages(ip); | |
255 | nblocks = dir_blocks(ip); | |
256 | pblocks = VXFS_BLOCK_PER_PAGE(sbp); | |
257 | ||
258 | page = pos >> PAGE_CACHE_SHIFT; | |
259 | offset = pos & ~PAGE_CACHE_MASK; | |
260 | block = (u_long)(pos >> sbp->s_blocksize_bits) % pblocks; | |
261 | ||
262 | for (; page < npages; page++, block = 0) { | |
9b5d5a17 | 263 | char *kaddr; |
1da177e4 LT |
264 | struct page *pp; |
265 | ||
266 | pp = vxfs_get_page(ip->i_mapping, page); | |
267 | if (IS_ERR(pp)) | |
268 | continue; | |
9b5d5a17 | 269 | kaddr = (char *)page_address(pp); |
1da177e4 LT |
270 | |
271 | for (; block <= nblocks && block <= pblocks; block++) { | |
9b5d5a17 | 272 | char *baddr, *limit; |
1da177e4 LT |
273 | struct vxfs_dirblk *dbp; |
274 | struct vxfs_direct *de; | |
275 | ||
276 | baddr = kaddr + (block * bsize); | |
277 | limit = baddr + bsize - VXFS_DIRLEN(1); | |
278 | ||
279 | dbp = (struct vxfs_dirblk *)baddr; | |
280 | de = (struct vxfs_direct *) | |
281 | (offset ? | |
282 | (kaddr + offset) : | |
283 | (baddr + VXFS_DIRBLKOV(dbp))); | |
284 | ||
9b5d5a17 | 285 | for (; (char *)de <= limit; de = vxfs_next_entry(de)) { |
1da177e4 LT |
286 | if (!de->d_reclen) |
287 | break; | |
288 | if (!de->d_ino) | |
289 | continue; | |
290 | ||
9b5d5a17 AV |
291 | offset = (char *)de - kaddr; |
292 | ctx->pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2; | |
293 | if (!dir_emit(ctx, de->d_name, de->d_namelen, | |
294 | de->d_ino, DT_UNKNOWN)) { | |
1da177e4 | 295 | vxfs_put_page(pp); |
9b5d5a17 | 296 | return 0; |
1da177e4 LT |
297 | } |
298 | } | |
299 | offset = 0; | |
300 | } | |
301 | vxfs_put_page(pp); | |
302 | offset = 0; | |
303 | } | |
9b5d5a17 | 304 | ctx->pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2; |
1da177e4 LT |
305 | return 0; |
306 | } |