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TOMOYO Linux Cross Reference
Linux/fs/sysv/namei.c

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  1 /*
  2  *  linux/fs/sysv/namei.c
  3  *
  4  *  minix/namei.c
  5  *  Copyright (C) 1991, 1992  Linus Torvalds
  6  *
  7  *  coh/namei.c
  8  *  Copyright (C) 1993  Pascal Haible, Bruno Haible
  9  *
 10  *  sysv/namei.c
 11  *  Copyright (C) 1993  Bruno Haible
 12  *  Copyright (C) 1997, 1998  Krzysztof G. Baranowski
 13  */
 14 
 15 #include <linux/pagemap.h>
 16 #include "sysv.h"
 17 
 18 static int add_nondir(struct dentry *dentry, struct inode *inode)
 19 {
 20         int err = sysv_add_link(dentry, inode);
 21         if (!err) {
 22                 d_instantiate(dentry, inode);
 23                 return 0;
 24         }
 25         inode_dec_link_count(inode);
 26         iput(inode);
 27         return err;
 28 }
 29 
 30 static int sysv_hash(const struct dentry *dentry, struct qstr *qstr)
 31 {
 32         /* Truncate the name in place, avoids having to define a compare
 33            function. */
 34         if (qstr->len > SYSV_NAMELEN) {
 35                 qstr->len = SYSV_NAMELEN;
 36                 qstr->hash = full_name_hash(qstr->name, qstr->len);
 37         }
 38         return 0;
 39 }
 40 
 41 const struct dentry_operations sysv_dentry_operations = {
 42         .d_hash         = sysv_hash,
 43 };
 44 
 45 static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
 46 {
 47         struct inode * inode = NULL;
 48         ino_t ino;
 49 
 50         if (dentry->d_name.len > SYSV_NAMELEN)
 51                 return ERR_PTR(-ENAMETOOLONG);
 52         ino = sysv_inode_by_name(dentry);
 53 
 54         if (ino) {
 55                 inode = sysv_iget(dir->i_sb, ino);
 56                 if (IS_ERR(inode))
 57                         return ERR_CAST(inode);
 58         }
 59         d_add(dentry, inode);
 60         return NULL;
 61 }
 62 
 63 static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev)
 64 {
 65         struct inode * inode;
 66         int err;
 67 
 68         if (!old_valid_dev(rdev))
 69                 return -EINVAL;
 70 
 71         inode = sysv_new_inode(dir, mode);
 72         err = PTR_ERR(inode);
 73 
 74         if (!IS_ERR(inode)) {
 75                 sysv_set_inode(inode, rdev);
 76                 mark_inode_dirty(inode);
 77                 err = add_nondir(dentry, inode);
 78         }
 79         return err;
 80 }
 81 
 82 static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, bool excl)
 83 {
 84         return sysv_mknod(dir, dentry, mode, 0);
 85 }
 86 
 87 static int sysv_symlink(struct inode * dir, struct dentry * dentry, 
 88         const char * symname)
 89 {
 90         int err = -ENAMETOOLONG;
 91         int l = strlen(symname)+1;
 92         struct inode * inode;
 93 
 94         if (l > dir->i_sb->s_blocksize)
 95                 goto out;
 96 
 97         inode = sysv_new_inode(dir, S_IFLNK|0777);
 98         err = PTR_ERR(inode);
 99         if (IS_ERR(inode))
100                 goto out;
101         
102         sysv_set_inode(inode, 0);
103         err = page_symlink(inode, symname, l);
104         if (err)
105                 goto out_fail;
106 
107         mark_inode_dirty(inode);
108         err = add_nondir(dentry, inode);
109 out:
110         return err;
111 
112 out_fail:
113         inode_dec_link_count(inode);
114         iput(inode);
115         goto out;
116 }
117 
118 static int sysv_link(struct dentry * old_dentry, struct inode * dir, 
119         struct dentry * dentry)
120 {
121         struct inode *inode = d_inode(old_dentry);
122 
123         inode->i_ctime = CURRENT_TIME_SEC;
124         inode_inc_link_count(inode);
125         ihold(inode);
126 
127         return add_nondir(dentry, inode);
128 }
129 
130 static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
131 {
132         struct inode * inode;
133         int err;
134 
135         inode_inc_link_count(dir);
136 
137         inode = sysv_new_inode(dir, S_IFDIR|mode);
138         err = PTR_ERR(inode);
139         if (IS_ERR(inode))
140                 goto out_dir;
141 
142         sysv_set_inode(inode, 0);
143 
144         inode_inc_link_count(inode);
145 
146         err = sysv_make_empty(inode, dir);
147         if (err)
148                 goto out_fail;
149 
150         err = sysv_add_link(dentry, inode);
151         if (err)
152                 goto out_fail;
153 
154         d_instantiate(dentry, inode);
155 out:
156         return err;
157 
158 out_fail:
159         inode_dec_link_count(inode);
160         inode_dec_link_count(inode);
161         iput(inode);
162 out_dir:
163         inode_dec_link_count(dir);
164         goto out;
165 }
166 
167 static int sysv_unlink(struct inode * dir, struct dentry * dentry)
168 {
169         struct inode * inode = d_inode(dentry);
170         struct page * page;
171         struct sysv_dir_entry * de;
172         int err = -ENOENT;
173 
174         de = sysv_find_entry(dentry, &page);
175         if (!de)
176                 goto out;
177 
178         err = sysv_delete_entry (de, page);
179         if (err)
180                 goto out;
181 
182         inode->i_ctime = dir->i_ctime;
183         inode_dec_link_count(inode);
184 out:
185         return err;
186 }
187 
188 static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
189 {
190         struct inode *inode = d_inode(dentry);
191         int err = -ENOTEMPTY;
192 
193         if (sysv_empty_dir(inode)) {
194                 err = sysv_unlink(dir, dentry);
195                 if (!err) {
196                         inode->i_size = 0;
197                         inode_dec_link_count(inode);
198                         inode_dec_link_count(dir);
199                 }
200         }
201         return err;
202 }
203 
204 /*
205  * Anybody can rename anything with this: the permission checks are left to the
206  * higher-level routines.
207  */
208 static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
209                   struct inode * new_dir, struct dentry * new_dentry)
210 {
211         struct inode * old_inode = d_inode(old_dentry);
212         struct inode * new_inode = d_inode(new_dentry);
213         struct page * dir_page = NULL;
214         struct sysv_dir_entry * dir_de = NULL;
215         struct page * old_page;
216         struct sysv_dir_entry * old_de;
217         int err = -ENOENT;
218 
219         old_de = sysv_find_entry(old_dentry, &old_page);
220         if (!old_de)
221                 goto out;
222 
223         if (S_ISDIR(old_inode->i_mode)) {
224                 err = -EIO;
225                 dir_de = sysv_dotdot(old_inode, &dir_page);
226                 if (!dir_de)
227                         goto out_old;
228         }
229 
230         if (new_inode) {
231                 struct page * new_page;
232                 struct sysv_dir_entry * new_de;
233 
234                 err = -ENOTEMPTY;
235                 if (dir_de && !sysv_empty_dir(new_inode))
236                         goto out_dir;
237 
238                 err = -ENOENT;
239                 new_de = sysv_find_entry(new_dentry, &new_page);
240                 if (!new_de)
241                         goto out_dir;
242                 sysv_set_link(new_de, new_page, old_inode);
243                 new_inode->i_ctime = CURRENT_TIME_SEC;
244                 if (dir_de)
245                         drop_nlink(new_inode);
246                 inode_dec_link_count(new_inode);
247         } else {
248                 err = sysv_add_link(new_dentry, old_inode);
249                 if (err)
250                         goto out_dir;
251                 if (dir_de)
252                         inode_inc_link_count(new_dir);
253         }
254 
255         sysv_delete_entry(old_de, old_page);
256         mark_inode_dirty(old_inode);
257 
258         if (dir_de) {
259                 sysv_set_link(dir_de, dir_page, new_dir);
260                 inode_dec_link_count(old_dir);
261         }
262         return 0;
263 
264 out_dir:
265         if (dir_de) {
266                 kunmap(dir_page);
267                 page_cache_release(dir_page);
268         }
269 out_old:
270         kunmap(old_page);
271         page_cache_release(old_page);
272 out:
273         return err;
274 }
275 
276 /*
277  * directories can handle most operations...
278  */
279 const struct inode_operations sysv_dir_inode_operations = {
280         .create         = sysv_create,
281         .lookup         = sysv_lookup,
282         .link           = sysv_link,
283         .unlink         = sysv_unlink,
284         .symlink        = sysv_symlink,
285         .mkdir          = sysv_mkdir,
286         .rmdir          = sysv_rmdir,
287         .mknod          = sysv_mknod,
288         .rename         = sysv_rename,
289         .getattr        = sysv_getattr,
290 };
291 

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