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Linux/fs/reiserfs/dir.c

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  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 "reiserfs.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, loff_t start, loff_t end,
 18                               int datasync);
 19 
 20 const struct file_operations reiserfs_dir_operations = {
 21         .llseek = generic_file_llseek,
 22         .read = generic_read_dir,
 23         .readdir = reiserfs_readdir,
 24         .fsync = reiserfs_dir_fsync,
 25         .unlocked_ioctl = reiserfs_ioctl,
 26 #ifdef CONFIG_COMPAT
 27         .compat_ioctl = reiserfs_compat_ioctl,
 28 #endif
 29 };
 30 
 31 static int reiserfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
 32                               int datasync)
 33 {
 34         struct inode *inode = filp->f_mapping->host;
 35         int err;
 36 
 37         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 38         if (err)
 39                 return err;
 40 
 41         mutex_lock(&inode->i_mutex);
 42         reiserfs_write_lock(inode->i_sb);
 43         err = reiserfs_commit_for_inode(inode);
 44         reiserfs_write_unlock(inode->i_sb);
 45         mutex_unlock(&inode->i_mutex);
 46         if (err < 0)
 47                 return err;
 48         return 0;
 49 }
 50 
 51 #define store_ih(where,what) copy_item_head (where, what)
 52 
 53 static inline bool is_privroot_deh(struct dentry *dir,
 54                                    struct reiserfs_de_head *deh)
 55 {
 56         struct dentry *privroot = REISERFS_SB(dir->d_sb)->priv_root;
 57         return (dir == dir->d_parent && privroot->d_inode &&
 58                 deh->deh_objectid == INODE_PKEY(privroot->d_inode)->k_objectid);
 59 }
 60 
 61 int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
 62                            filldir_t filldir, loff_t *pos)
 63 {
 64         struct inode *inode = dentry->d_inode;
 65         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
 66         INITIALIZE_PATH(path_to_entry);
 67         struct buffer_head *bh;
 68         int item_num, entry_num;
 69         const struct reiserfs_key *rkey;
 70         struct item_head *ih, tmp_ih;
 71         int search_res;
 72         char *local_buf;
 73         loff_t next_pos;
 74         char small_buf[32];     /* avoid kmalloc if we can */
 75         struct reiserfs_dir_entry de;
 76         int ret = 0;
 77 
 78         reiserfs_write_lock(inode->i_sb);
 79 
 80         reiserfs_check_lock_depth(inode->i_sb, "readdir");
 81 
 82         /* form key for search the next directory entry using f_pos field of
 83            file structure */
 84         make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
 85         next_pos = cpu_key_k_offset(&pos_key);
 86 
 87         path_to_entry.reada = PATH_READA;
 88         while (1) {
 89               research:
 90                 /* search the directory item, containing entry with specified key */
 91                 search_res =
 92                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
 93                                         &de);
 94                 if (search_res == IO_ERROR) {
 95                         // FIXME: we could just skip part of directory which could
 96                         // not be read
 97                         ret = -EIO;
 98                         goto out;
 99                 }
100                 entry_num = de.de_entry_num;
101                 bh = de.de_bh;
102                 item_num = de.de_item_num;
103                 ih = de.de_ih;
104                 store_ih(&tmp_ih, ih);
105 
106                 /* we must have found item, that is item of this directory, */
107                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
108                        "vs-9000: found item %h does not match to dir we readdir %K",
109                        ih, &pos_key);
110                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
111                        "vs-9005 item_num == %d, item amount == %d",
112                        item_num, B_NR_ITEMS(bh));
113 
114                 /* and entry must be not more than number of entries in the item */
115                 RFALSE(I_ENTRY_COUNT(ih) < entry_num,
116                        "vs-9010: entry number is too big %d (%d)",
117                        entry_num, I_ENTRY_COUNT(ih));
118 
119                 if (search_res == POSITION_FOUND
120                     || entry_num < I_ENTRY_COUNT(ih)) {
121                         /* go through all entries in the directory item beginning from the entry, that has been found */
122                         struct reiserfs_de_head *deh =
123                             B_I_DEH(bh, ih) + entry_num;
124 
125                         for (; entry_num < I_ENTRY_COUNT(ih);
126                              entry_num++, deh++) {
127                                 int d_reclen;
128                                 char *d_name;
129                                 off_t d_off;
130                                 ino_t d_ino;
131 
132                                 if (!de_visible(deh))
133                                         /* it is hidden entry */
134                                         continue;
135                                 d_reclen = entry_length(bh, ih, entry_num);
136                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
137 
138                                 if (d_reclen <= 0 ||
139                                     d_name + d_reclen > bh->b_data + bh->b_size) {
140                                         /* There is corrupted data in entry,
141                                          * We'd better stop here */
142                                         pathrelse(&path_to_entry);
143                                         ret = -EIO;
144                                         goto out;
145                                 }
146 
147                                 if (!d_name[d_reclen - 1])
148                                         d_reclen = strlen(d_name);
149 
150                                 if (d_reclen >
151                                     REISERFS_MAX_NAME(inode->i_sb->
152                                                       s_blocksize)) {
153                                         /* too big to send back to VFS */
154                                         continue;
155                                 }
156 
157                                 /* Ignore the .reiserfs_priv entry */
158                                 if (is_privroot_deh(dentry, deh))
159                                         continue;
160 
161                                 d_off = deh_offset(deh);
162                                 *pos = d_off;
163                                 d_ino = deh_objectid(deh);
164                                 if (d_reclen <= 32) {
165                                         local_buf = small_buf;
166                                 } else {
167                                         local_buf = kmalloc(d_reclen,
168                                                             GFP_NOFS);
169                                         if (!local_buf) {
170                                                 pathrelse(&path_to_entry);
171                                                 ret = -ENOMEM;
172                                                 goto out;
173                                         }
174                                         if (item_moved(&tmp_ih, &path_to_entry)) {
175                                                 kfree(local_buf);
176                                                 goto research;
177                                         }
178                                 }
179                                 // Note, that we copy name to user space via temporary
180                                 // buffer (local_buf) because filldir will block if
181                                 // user space buffer is swapped out. At that time
182                                 // entry can move to somewhere else
183                                 memcpy(local_buf, d_name, d_reclen);
184 
185                                 /*
186                                  * Since filldir might sleep, we can release
187                                  * the write lock here for other waiters
188                                  */
189                                 reiserfs_write_unlock(inode->i_sb);
190                                 if (filldir
191                                     (dirent, local_buf, d_reclen, d_off, d_ino,
192                                      DT_UNKNOWN) < 0) {
193                                         reiserfs_write_lock(inode->i_sb);
194                                         if (local_buf != small_buf) {
195                                                 kfree(local_buf);
196                                         }
197                                         goto end;
198                                 }
199                                 reiserfs_write_lock(inode->i_sb);
200                                 if (local_buf != small_buf) {
201                                         kfree(local_buf);
202                                 }
203                                 // next entry should be looked for with such offset
204                                 next_pos = deh_offset(deh) + 1;
205 
206                                 if (item_moved(&tmp_ih, &path_to_entry)) {
207                                         goto research;
208                                 }
209                         }       /* for */
210                 }
211 
212                 if (item_num != B_NR_ITEMS(bh) - 1)
213                         // end of directory has been reached
214                         goto end;
215 
216                 /* item we went through is last item of node. Using right
217                    delimiting key check is it directory end */
218                 rkey = get_rkey(&path_to_entry, inode->i_sb);
219                 if (!comp_le_keys(rkey, &MIN_KEY)) {
220                         /* set pos_key to key, that is the smallest and greater
221                            that key of the last entry in the item */
222                         set_cpu_key_k_offset(&pos_key, next_pos);
223                         continue;
224                 }
225 
226                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
227                         // end of directory has been reached
228                         goto end;
229                 }
230 
231                 /* directory continues in the right neighboring block */
232                 set_cpu_key_k_offset(&pos_key,
233                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
234 
235         }                       /* while */
236 
237 end:
238         *pos = next_pos;
239         pathrelse(&path_to_entry);
240         reiserfs_check_path(&path_to_entry);
241 out:
242         reiserfs_write_unlock(inode->i_sb);
243         return ret;
244 }
245 
246 static int reiserfs_readdir(struct file *file, void *dirent, filldir_t filldir)
247 {
248         struct dentry *dentry = file->f_path.dentry;
249         return reiserfs_readdir_dentry(dentry, dirent, filldir, &file->f_pos);
250 }
251 
252 /* compose directory item containing "." and ".." entries (entries are
253    not aligned to 4 byte boundary) */
254 /* the last four params are LE */
255 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
256                             __le32 par_dirid, __le32 par_objid)
257 {
258         struct reiserfs_de_head *deh;
259 
260         memset(body, 0, EMPTY_DIR_SIZE_V1);
261         deh = (struct reiserfs_de_head *)body;
262 
263         /* direntry header of "." */
264         put_deh_offset(&(deh[0]), DOT_OFFSET);
265         /* these two are from make_le_item_head, and are are LE */
266         deh[0].deh_dir_id = dirid;
267         deh[0].deh_objectid = objid;
268         deh[0].deh_state = 0;   /* Endian safe if 0 */
269         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
270         mark_de_visible(&(deh[0]));
271 
272         /* direntry header of ".." */
273         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
274         /* key of ".." for the root directory */
275         /* these two are from the inode, and are are LE */
276         deh[1].deh_dir_id = par_dirid;
277         deh[1].deh_objectid = par_objid;
278         deh[1].deh_state = 0;   /* Endian safe if 0 */
279         put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
280         mark_de_visible(&(deh[1]));
281 
282         /* copy ".." and "." */
283         memcpy(body + deh_location(&(deh[0])), ".", 1);
284         memcpy(body + deh_location(&(deh[1])), "..", 2);
285 }
286 
287 /* compose directory item containing "." and ".." entries */
288 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
289                          __le32 par_dirid, __le32 par_objid)
290 {
291         struct reiserfs_de_head *deh;
292 
293         memset(body, 0, EMPTY_DIR_SIZE);
294         deh = (struct reiserfs_de_head *)body;
295 
296         /* direntry header of "." */
297         put_deh_offset(&(deh[0]), DOT_OFFSET);
298         /* these two are from make_le_item_head, and are are LE */
299         deh[0].deh_dir_id = dirid;
300         deh[0].deh_objectid = objid;
301         deh[0].deh_state = 0;   /* Endian safe if 0 */
302         put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
303         mark_de_visible(&(deh[0]));
304 
305         /* direntry header of ".." */
306         put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
307         /* key of ".." for the root directory */
308         /* these two are from the inode, and are are LE */
309         deh[1].deh_dir_id = par_dirid;
310         deh[1].deh_objectid = par_objid;
311         deh[1].deh_state = 0;   /* Endian safe if 0 */
312         put_deh_location(&(deh[1]),
313                          deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
314         mark_de_visible(&(deh[1]));
315 
316         /* copy ".." and "." */
317         memcpy(body + deh_location(&(deh[0])), ".", 1);
318         memcpy(body + deh_location(&(deh[1])), "..", 2);
319 }
320 

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