reiserfs: fix permissions on .reiserfs_priv
[linux-2.6.git] / fs / reiserfs / dir.c
1 /*
2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
3  */
4
5 #include <linux/string.h>
6 #include <linux/errno.h>
7 #include <linux/fs.h>
8 #include <linux/reiserfs_fs.h>
9 #include <linux/stat.h>
10 #include <linux/buffer_head.h>
11 #include <linux/slab.h>
12 #include <asm/uaccess.h>
13
14 extern const struct reiserfs_key MIN_KEY;
15
16 static int reiserfs_readdir(struct file *, void *, filldir_t);
17 static int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry,
18                               int datasync);
19
20 const struct file_operations reiserfs_dir_operations = {
21         .read = generic_read_dir,
22         .readdir = reiserfs_readdir,
23         .fsync = reiserfs_dir_fsync,
24         .unlocked_ioctl = reiserfs_ioctl,
25 #ifdef CONFIG_COMPAT
26         .compat_ioctl = reiserfs_compat_ioctl,
27 #endif
28 };
29
30 static int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry,
31                               int datasync)
32 {
33         struct inode *inode = dentry->d_inode;
34         int err;
35         reiserfs_write_lock(inode->i_sb);
36         err = reiserfs_commit_for_inode(inode);
37         reiserfs_write_unlock(inode->i_sb);
38         if (err < 0)
39                 return err;
40         return 0;
41 }
42
43 #define store_ih(where,what) copy_item_head (where, what)
44
45 static inline bool is_privroot_deh(struct dentry *dir,
46                                    struct reiserfs_de_head *deh)
47 {
48         struct dentry *privroot = REISERFS_SB(dir->d_sb)->priv_root;
49         return (dir == dir->d_parent && privroot->d_inode &&
50                 deh->deh_objectid == INODE_PKEY(privroot->d_inode)->k_objectid);
51 }
52
53 int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
54                            filldir_t filldir, loff_t *pos)
55 {
56         struct inode *inode = dentry->d_inode;
57         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
58         INITIALIZE_PATH(path_to_entry);
59         struct buffer_head *bh;
60         int item_num, entry_num;
61         const struct reiserfs_key *rkey;
62         struct item_head *ih, tmp_ih;
63         int search_res;
64         char *local_buf;
65         loff_t next_pos;
66         char small_buf[32];     /* avoid kmalloc if we can */
67         struct reiserfs_dir_entry de;
68         int ret = 0;
69
70         reiserfs_write_lock(inode->i_sb);
71
72         reiserfs_check_lock_depth(inode->i_sb, "readdir");
73
74         /* form key for search the next directory entry using f_pos field of
75            file structure */
76         make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
77         next_pos = cpu_key_k_offset(&pos_key);
78
79         path_to_entry.reada = PATH_READA;
80         while (1) {
81               research:
82                 /* search the directory item, containing entry with specified key */
83                 search_res =
84                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
85                                         &de);
86                 if (search_res == IO_ERROR) {
87                         // FIXME: we could just skip part of directory which could
88                         // not be read
89                         ret = -EIO;
90                         goto out;
91                 }
92                 entry_num = de.de_entry_num;
93                 bh = de.de_bh;
94                 item_num = de.de_item_num;
95                 ih = de.de_ih;
96                 store_ih(&tmp_ih, ih);
97
98                 /* we must have found item, that is item of this directory, */
99                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
100                        "vs-9000: found item %h does not match to dir we readdir %K",
101                        ih, &pos_key);
102                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
103                        "vs-9005 item_num == %d, item amount == %d",
104                        item_num, B_NR_ITEMS(bh));
105
106                 /* and entry must be not more than number of entries in the item */
107                 RFALSE(I_ENTRY_COUNT(ih) < entry_num,
108                        "vs-9010: entry number is too big %d (%d)",
109                        entry_num, I_ENTRY_COUNT(ih));
110
111                 if (search_res == POSITION_FOUND
112                     || entry_num < I_ENTRY_COUNT(ih)) {
113                         /* go through all entries in the directory item beginning from the entry, that has been found */
114                         struct reiserfs_de_head *deh =
115                             B_I_DEH(bh, ih) + entry_num;
116
117                         for (; entry_num < I_ENTRY_COUNT(ih);
118                              entry_num++, deh++) {
119                                 int d_reclen;
120                                 char *d_name;
121                                 off_t d_off;
122                                 ino_t d_ino;
123
124                                 if (!de_visible(deh))
125                                         /* it is hidden entry */
126                                         continue;
127                                 d_reclen = entry_length(bh, ih, entry_num);
128                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
129
130                                 if (d_reclen <= 0 ||
131                                     d_name + d_reclen > bh->b_data + bh->b_size) {
132                                         /* There is corrupted data in entry,
133                                          * We'd better stop here */
134                                         pathrelse(&path_to_entry);
135                                         ret = -EIO;
136                                         goto out;
137                                 }
138
139                                 if (!d_name[d_reclen - 1])
140                                         d_reclen = strlen(d_name);
141
142                                 if (d_reclen >
143                                     REISERFS_MAX_NAME(inode->i_sb->
144                                                       s_blocksize)) {
145                                         /* too big to send back to VFS */
146                                         continue;
147                                 }
148
149                                 /* Ignore the .reiserfs_priv entry */
150                                 if (is_privroot_deh(dentry, deh))
151                                         continue;
152
153                                 d_off = deh_offset(deh);
154                                 *pos = d_off;
155                                 d_ino = deh_objectid(deh);
156                                 if (d_reclen <= 32) {
157                                         local_buf = small_buf;
158                                 } else {
159                                         local_buf = kmalloc(d_reclen,
160                                                             GFP_NOFS);
161                                         if (!local_buf) {
162                                                 pathrelse(&path_to_entry);
163                                                 ret = -ENOMEM;
164                                                 goto out;
165                                         }
166                                         if (item_moved(&tmp_ih, &path_to_entry)) {
167                                                 kfree(local_buf);
168                                                 goto research;
169                                         }
170                                 }
171                                 // Note, that we copy name to user space via temporary
172                                 // buffer (local_buf) because filldir will block if
173                                 // user space buffer is swapped out. At that time
174                                 // entry can move to somewhere else
175                                 memcpy(local_buf, d_name, d_reclen);
176
177                                 /*
178                                  * Since filldir might sleep, we can release
179                                  * the write lock here for other waiters
180                                  */
181                                 reiserfs_write_unlock(inode->i_sb);
182                                 if (filldir
183                                     (dirent, local_buf, d_reclen, d_off, d_ino,
184                                      DT_UNKNOWN) < 0) {
185                                         reiserfs_write_lock(inode->i_sb);
186                                         if (local_buf != small_buf) {
187                                                 kfree(local_buf);
188                                         }
189                                         goto end;
190                                 }
191                                 reiserfs_write_lock(inode->i_sb);
192                                 if (local_buf != small_buf) {
193                                         kfree(local_buf);
194                                 }
195                                 // next entry should be looked for with such offset
196                                 next_pos = deh_offset(deh) + 1;
197
198                                 if (item_moved(&tmp_ih, &path_to_entry)) {
199                                         goto research;
200                                 }
201                         }       /* for */
202                 }
203
204                 if (item_num != B_NR_ITEMS(bh) - 1)
205                         // end of directory has been reached
206                         goto end;
207
208                 /* item we went through is last item of node. Using right
209                    delimiting key check is it directory end */
210                 rkey = get_rkey(&path_to_entry, inode->i_sb);
211                 if (!comp_le_keys(rkey, &MIN_KEY)) {
212                         /* set pos_key to key, that is the smallest and greater
213                            that key of the last entry in the item */
214                         set_cpu_key_k_offset(&pos_key, next_pos);
215                         continue;
216                 }
217
218                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
219                         // end of directory has been reached
220                         goto end;
221                 }
222
223                 /* directory continues in the right neighboring block */
224                 set_cpu_key_k_offset(&pos_key,
225                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
226
227         }                       /* while */
228
229 end:
230         *pos = next_pos;
231         pathrelse(&path_to_entry);
232         reiserfs_check_path(&path_to_entry);
233 out:
234         reiserfs_write_unlock(inode->i_sb);
235         return ret;
236 }
237
238 static int reiserfs_readdir(struct file *file, void *dirent, filldir_t filldir)
239 {
240         struct dentry *dentry = file->f_path.dentry;
241         return reiserfs_readdir_dentry(dentry, dirent, filldir, &file->f_pos);
242 }
243
244 /* compose directory item containing "." and ".." entries (entries are
245    not aligned to 4 byte boundary) */
246 /* the last four params are LE */
247 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
248                             __le32 par_dirid, __le32 par_objid)
249 {
250         struct reiserfs_de_head *deh;
251
252         memset(body, 0, EMPTY_DIR_SIZE_V1);
253         deh = (struct reiserfs_de_head *)body;
254
255         /* direntry header of "." */
256         put_deh_offset(&(deh[0]), DOT_OFFSET);
257         /* these two are from make_le_item_head, and are are LE */
258         deh[0].deh_dir_id = dirid;
259         deh[0].deh_objectid = objid;
260         deh[0].deh_state = 0;   /* Endian safe if 0 */
261         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
262         mark_de_visible(&(deh[0]));
263
264         /* direntry header of ".." */
265         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
266         /* key of ".." for the root directory */
267         /* these two are from the inode, and are are LE */
268         deh[1].deh_dir_id = par_dirid;
269         deh[1].deh_objectid = par_objid;
270         deh[1].deh_state = 0;   /* Endian safe if 0 */
271         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
272         mark_de_visible(&(deh[1]));
273
274         /* copy ".." and "." */
275         memcpy(body + deh_location(&(deh[0])), ".", 1);
276         memcpy(body + deh_location(&(deh[1])), "..", 2);
277 }
278
279 /* compose directory item containing "." and ".." entries */
280 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
281                          __le32 par_dirid, __le32 par_objid)
282 {
283         struct reiserfs_de_head *deh;
284
285         memset(body, 0, EMPTY_DIR_SIZE);
286         deh = (struct reiserfs_de_head *)body;
287
288         /* direntry header of "." */
289         put_deh_offset(&(deh[0]), DOT_OFFSET);
290         /* these two are from make_le_item_head, and are are LE */
291         deh[0].deh_dir_id = dirid;
292         deh[0].deh_objectid = objid;
293         deh[0].deh_state = 0;   /* Endian safe if 0 */
294         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
295         mark_de_visible(&(deh[0]));
296
297         /* direntry header of ".." */
298         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
299         /* key of ".." for the root directory */
300         /* these two are from the inode, and are are LE */
301         deh[1].deh_dir_id = par_dirid;
302         deh[1].deh_objectid = par_objid;
303         deh[1].deh_state = 0;   /* Endian safe if 0 */
304         put_deh_location(&(deh[1]),
305                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
306         mark_de_visible(&(deh[1]));
307
308         /* copy ".." and "." */
309         memcpy(body + deh_location(&(deh[0])), ".", 1);
310         memcpy(body + deh_location(&(deh[1])), "..", 2);
311 }