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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [fs/] [ext2/] [namei.c] - Blame information for rev 1275

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Line No. Rev Author Line
1 1275 phoenix 
/*
2 
 * linux/fs/ext2/namei.c
3 
 *
4 
 * Rewrite to pagecache. Almost all code had been changed, so blame me
5 
 * if the things go wrong. Please, send bug reports to viro@math.psu.edu
6 
 *
7 
 * Stuff here is basically a glue between the VFS and generic UNIXish
8 
 * filesystem that keeps everything in pagecache. All knowledge of the
9 
 * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
10 
 * and it's easier to debug that way. In principle we might want to
11 
 * generalize that a bit and turn it into a library. Or not.
12 
 *
13 
 * The only non-static object here is ext2_dir_inode_operations.
14 
 *
15 
 * TODO: get rid of kmap() use, add readahead.
16 
 *
17 
 * Copyright (C) 1992, 1993, 1994, 1995
18 
 * Remy Card (card@masi.ibp.fr)
19 
 * Laboratoire MASI - Institut Blaise Pascal
20 
 * Universite Pierre et Marie Curie (Paris VI)
21 
 *
22 
 *  from
23 
 *
24 
 *  linux/fs/minix/namei.c
25 
 *
26 
 *  Copyright (C) 1991, 1992  Linus Torvalds
27 
 *
28 
 *  Big-endian to little-endian byte-swapping/bitmaps by
29 
 *        David S. Miller (davem@caip.rutgers.edu), 1995
30 
 */
31 
 
32 
#include <linux/fs.h>
33 
#include <linux/ext2_fs.h>
34 
#include <linux/pagemap.h>
35 
 
36 
/*
37 
 * Couple of helper functions - make the code slightly cleaner.
38 
 */
39 
 
40 
static inline void ext2_inc_count(struct inode *inode)
41 
{
42 
        inode->i_nlink++;
43 
        mark_inode_dirty(inode);
44 
}
45 
 
46 
static inline void ext2_dec_count(struct inode *inode)
47 
{
48 
        inode->i_nlink--;
49 
        mark_inode_dirty(inode);
50 
}
51 
 
52 
static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
53 
{
54 
        int err = ext2_add_link(dentry, inode);
55 
        if (!err) {
56 
                d_instantiate(dentry, inode);
57 
                return 0;
58 
        }
59 
        ext2_dec_count(inode);
60 
        iput(inode);
61 
        return err;
62 
}
63 
 
64 
/*
65 
 * Methods themselves.
66 
 */
67 
 
68 
static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry)
69 
{
70 
        struct inode * inode;
71 
        ino_t ino;
72 
 
73 
        if (dentry->d_name.len > EXT2_NAME_LEN)
74 
                return ERR_PTR(-ENAMETOOLONG);
75 
 
76 
        ino = ext2_inode_by_name(dir, dentry);
77 
        inode = NULL;
78 
        if (ino) {
79 
                inode = iget(dir->i_sb, ino);
80 
                if (!inode)
81 
                        return ERR_PTR(-EACCES);
82 
        }
83 
        d_add(dentry, inode);
84 
        return NULL;
85 
}
86 
 
87 
/*
88 
 * By the time this is called, we already have created
89 
 * the directory cache entry for the new file, but it
90 
 * is so far negative - it has no inode.
91 
 *
92 
 * If the create succeeds, we fill in the inode information
93 
 * with d_instantiate().
94 
 */
95 
static int ext2_create (struct inode * dir, struct dentry * dentry, int mode)
96 
{
97 
        struct inode * inode = ext2_new_inode (dir, mode);
98 
        int err = PTR_ERR(inode);
99 
        if (!IS_ERR(inode)) {
100 
                inode->i_op = &ext2_file_inode_operations;
101 
                inode->i_fop = &ext2_file_operations;
102 
                inode->i_mapping->a_ops = &ext2_aops;
103 
                mark_inode_dirty(inode);
104 
                err = ext2_add_nondir(dentry, inode);
105 
        }
106 
        return err;
107 
}
108 
 
109 
static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, int rdev)
110 
{
111 
        struct inode * inode = ext2_new_inode (dir, mode);
112 
        int err = PTR_ERR(inode);
113 
        if (!IS_ERR(inode)) {
114 
                init_special_inode(inode, mode, rdev);
115 
                mark_inode_dirty(inode);
116 
                err = ext2_add_nondir(dentry, inode);
117 
        }
118 
        return err;
119 
}
120 
 
121 
static int ext2_symlink (struct inode * dir, struct dentry * dentry,
122 
        const char * symname)
123 
{
124 
        struct super_block * sb = dir->i_sb;
125 
        int err = -ENAMETOOLONG;
126 
        unsigned l = strlen(symname)+1;
127 
        struct inode * inode;
128 
 
129 
        if (l > sb->s_blocksize)
130 
                goto out;
131 
 
132 
        inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO);
133 
        err = PTR_ERR(inode);
134 
        if (IS_ERR(inode))
135 
                goto out;
136 
 
137 
        if (l > sizeof (inode->u.ext2_i.i_data)) {
138 
                /* slow symlink */
139 
                inode->i_op = &page_symlink_inode_operations;
140 
                inode->i_mapping->a_ops = &ext2_aops;
141 
                err = block_symlink(inode, symname, l);
142 
                if (err)
143 
                        goto out_fail;
144 
        } else {
145 
                /* fast symlink */
146 
                inode->i_op = &ext2_fast_symlink_inode_operations;
147 
                memcpy((char*)&inode->u.ext2_i.i_data,symname,l);
148 
                inode->i_size = l-1;
149 
        }
150 
        mark_inode_dirty(inode);
151 
 
152 
        err = ext2_add_nondir(dentry, inode);
153 
out:
154 
        return err;
155 
 
156 
out_fail:
157 
        ext2_dec_count(inode);
158 
        iput (inode);
159 
        goto out;
160 
}
161 
 
162 
static int ext2_link (struct dentry * old_dentry, struct inode * dir,
163 
        struct dentry *dentry)
164 
{
165 
        struct inode *inode = old_dentry->d_inode;
166 
 
167 
        if (S_ISDIR(inode->i_mode))
168 
                return -EPERM;
169 
 
170 
        if (inode->i_nlink >= EXT2_LINK_MAX)
171 
                return -EMLINK;
172 
 
173 
        inode->i_ctime = CURRENT_TIME;
174 
        ext2_inc_count(inode);
175 
        atomic_inc(&inode->i_count);
176 
 
177 
        return ext2_add_nondir(dentry, inode);
178 
}
179 
 
180 
static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
181 
{
182 
        struct inode * inode;
183 
        int err = -EMLINK;
184 
 
185 
        if (dir->i_nlink >= EXT2_LINK_MAX)
186 
                goto out;
187 
 
188 
        ext2_inc_count(dir);
189 
 
190 
        inode = ext2_new_inode (dir, S_IFDIR | mode);
191 
        err = PTR_ERR(inode);
192 
        if (IS_ERR(inode))
193 
                goto out_dir;
194 
 
195 
        inode->i_op = &ext2_dir_inode_operations;
196 
        inode->i_fop = &ext2_dir_operations;
197 
        inode->i_mapping->a_ops = &ext2_aops;
198 
 
199 
        ext2_inc_count(inode);
200 
 
201 
        err = ext2_make_empty(inode, dir);
202 
        if (err)
203 
                goto out_fail;
204 
 
205 
        err = ext2_add_link(dentry, inode);
206 
        if (err)
207 
                goto out_fail;
208 
 
209 
        d_instantiate(dentry, inode);
210 
out:
211 
        return err;
212 
 
213 
out_fail:
214 
        ext2_dec_count(inode);
215 
        ext2_dec_count(inode);
216 
        iput(inode);
217 
out_dir:
218 
        ext2_dec_count(dir);
219 
        goto out;
220 
}
221 
 
222 
static int ext2_unlink(struct inode * dir, struct dentry *dentry)
223 
{
224 
        struct inode * inode = dentry->d_inode;
225 
        struct ext2_dir_entry_2 * de;
226 
        struct page * page;
227 
        int err = -ENOENT;
228 
 
229 
        de = ext2_find_entry (dir, dentry, &page);
230 
        if (!de)
231 
                goto out;
232 
 
233 
        err = ext2_delete_entry (de, page);
234 
        if (err)
235 
                goto out;
236 
 
237 
        inode->i_ctime = dir->i_ctime;
238 
        ext2_dec_count(inode);
239 
        err = 0;
240 
out:
241 
        return err;
242 
}
243 
 
244 
static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
245 
{
246 
        struct inode * inode = dentry->d_inode;
247 
        int err = -ENOTEMPTY;
248 
 
249 
        if (ext2_empty_dir(inode)) {
250 
                err = ext2_unlink(dir, dentry);
251 
                if (!err) {
252 
                        inode->i_size = 0;
253 
                        ext2_dec_count(inode);
254 
                        ext2_dec_count(dir);
255 
                }
256 
        }
257 
        return err;
258 
}
259 
 
260 
static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
261 
        struct inode * new_dir, struct dentry * new_dentry )
262 
{
263 
        struct inode * old_inode = old_dentry->d_inode;
264 
        struct inode * new_inode = new_dentry->d_inode;
265 
        struct page * dir_page = NULL;
266 
        struct ext2_dir_entry_2 * dir_de = NULL;
267 
        struct page * old_page;
268 
        struct ext2_dir_entry_2 * old_de;
269 
        int err = -ENOENT;
270 
 
271 
        old_de = ext2_find_entry (old_dir, old_dentry, &old_page);
272 
        if (!old_de)
273 
                goto out;
274 
 
275 
        if (S_ISDIR(old_inode->i_mode)) {
276 
                err = -EIO;
277 
                dir_de = ext2_dotdot(old_inode, &dir_page);
278 
                if (!dir_de)
279 
                        goto out_old;
280 
        }
281 
 
282 
        if (new_inode) {
283 
                struct page *new_page;
284 
                struct ext2_dir_entry_2 *new_de;
285 
 
286 
                err = -ENOTEMPTY;
287 
                if (dir_de && !ext2_empty_dir (new_inode))
288 
                        goto out_dir;
289 
 
290 
                err = -ENOENT;
291 
                new_de = ext2_find_entry (new_dir, new_dentry, &new_page);
292 
                if (!new_de)
293 
                        goto out_dir;
294 
                ext2_inc_count(old_inode);
295 
                ext2_set_link(new_dir, new_de, new_page, old_inode);
296 
                new_inode->i_ctime = CURRENT_TIME;
297 
                if (dir_de)
298 
                        new_inode->i_nlink--;
299 
                ext2_dec_count(new_inode);
300 
        } else {
301 
                if (dir_de) {
302 
                        err = -EMLINK;
303 
                        if (new_dir->i_nlink >= EXT2_LINK_MAX)
304 
                                goto out_dir;
305 
                }
306 
                ext2_inc_count(old_inode);
307 
                err = ext2_add_link(new_dentry, old_inode);
308 
                if (err) {
309 
                        ext2_dec_count(old_inode);
310 
                        goto out_dir;
311 
                }
312 
                if (dir_de)
313 
                        ext2_inc_count(new_dir);
314 
        }
315 
 
316 
        ext2_delete_entry (old_de, old_page);
317 
        ext2_dec_count(old_inode);
318 
 
319 
        if (dir_de) {
320 
                ext2_set_link(old_inode, dir_de, dir_page, new_dir);
321 
                ext2_dec_count(old_dir);
322 
        }
323 
        return 0;
324 
 
325 
 
326 
out_dir:
327 
        if (dir_de) {
328 
                kunmap(dir_page);
329 
                page_cache_release(dir_page);
330 
        }
331 
out_old:
332 
        kunmap(old_page);
333 
        page_cache_release(old_page);
334 
out:
335 
        return err;
336 
}
337 
 
338 
struct inode_operations ext2_dir_inode_operations = {
339 
        create:         ext2_create,
340 
        lookup:         ext2_lookup,
341 
        link:           ext2_link,
342 
        unlink:         ext2_unlink,
343 
        symlink:        ext2_symlink,
344 
        mkdir:          ext2_mkdir,
345 
        rmdir:          ext2_rmdir,
346 
        mknod:          ext2_mknod,
347 
        rename:         ext2_rename,
348 
};

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