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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 <linux/uaccess.h>
 13 
 14 extern const struct reiserfs_key MIN_KEY;
 15 
 16 static int reiserfs_readdir(struct file *, struct dir_context *);
 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         .iterate_shared = 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 = file_write_and_wait_range(filp, start, end);
 38         if (err)
 39                 return err;
 40 
 41         inode_lock(inode);
 42         reiserfs_write_lock(inode->i_sb);
 43         err = reiserfs_commit_for_inode(inode);
 44         reiserfs_write_unlock(inode->i_sb);
 45         inode_unlock(inode);
 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 inode *dir, struct reiserfs_de_head *deh)
 54 {
 55         struct dentry *privroot = REISERFS_SB(dir->i_sb)->priv_root;
 56         return (d_really_is_positive(privroot) &&
 57                 deh->deh_objectid == INODE_PKEY(d_inode(privroot))->k_objectid);
 58 }
 59 
 60 int reiserfs_readdir_inode(struct inode *inode, struct dir_context *ctx)
 61 {
 62 
 63         /* key of current position in the directory (key of directory entry) */
 64         struct cpu_key pos_key;
 65 
 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         int depth;
 78 
 79         reiserfs_write_lock(inode->i_sb);
 80 
 81         reiserfs_check_lock_depth(inode->i_sb, "readdir");
 82 
 83         /*
 84          * form key for search the next directory entry using
 85          * f_pos field of file structure
 86          */
 87         make_cpu_key(&pos_key, inode, ctx->pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
 88         next_pos = cpu_key_k_offset(&pos_key);
 89 
 90         path_to_entry.reada = PATH_READA;
 91         while (1) {
 92 research:
 93                 /*
 94                  * search the directory item, containing entry with
 95                  * specified key
 96                  */
 97                 search_res =
 98                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
 99                                         &de);
100                 if (search_res == IO_ERROR) {
101                         /*
102                          * FIXME: we could just skip part of directory
103                          * which could not be read
104                          */
105                         ret = -EIO;
106                         goto out;
107                 }
108                 entry_num = de.de_entry_num;
109                 bh = de.de_bh;
110                 item_num = de.de_item_num;
111                 ih = de.de_ih;
112                 store_ih(&tmp_ih, ih);
113 
114                 /* we must have found item, that is item of this directory, */
115                 RFALSE(COMP_SHORT_KEYS(&ih->ih_key, &pos_key),
116                        "vs-9000: found item %h does not match to dir we readdir %K",
117                        ih, &pos_key);
118                 RFALSE(item_num > B_NR_ITEMS(bh) - 1,
119                        "vs-9005 item_num == %d, item amount == %d",
120                        item_num, B_NR_ITEMS(bh));
121 
122                 /*
123                  * and entry must be not more than number of entries
124                  * in the item
125                  */
126                 RFALSE(ih_entry_count(ih) < entry_num,
127                        "vs-9010: entry number is too big %d (%d)",
128                        entry_num, ih_entry_count(ih));
129 
130                 /*
131                  * go through all entries in the directory item beginning
132                  * from the entry, that has been found
133                  */
134                 if (search_res == POSITION_FOUND
135                     || entry_num < ih_entry_count(ih)) {
136                         struct reiserfs_de_head *deh =
137                             B_I_DEH(bh, ih) + entry_num;
138 
139                         for (; entry_num < ih_entry_count(ih);
140                              entry_num++, deh++) {
141                                 int d_reclen;
142                                 char *d_name;
143                                 ino_t d_ino;
144                                 loff_t cur_pos = deh_offset(deh);
145 
146                                 /* it is hidden entry */
147                                 if (!de_visible(deh))
148                                         continue;
149                                 d_reclen = entry_length(bh, ih, entry_num);
150                                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
151 
152                                 if (d_reclen <= 0 ||
153                                     d_name + d_reclen > bh->b_data + bh->b_size) {
154                                         /*
155                                          * There is corrupted data in entry,
156                                          * We'd better stop here
157                                          */
158                                         pathrelse(&path_to_entry);
159                                         ret = -EIO;
160                                         goto out;
161                                 }
162 
163                                 if (!d_name[d_reclen - 1])
164                                         d_reclen = strlen(d_name);
165 
166                                 /* too big to send back to VFS */
167                                 if (d_reclen >
168                                     REISERFS_MAX_NAME(inode->i_sb->
169                                                       s_blocksize)) {
170                                         continue;
171                                 }
172 
173                                 /* Ignore the .reiserfs_priv entry */
174                                 if (is_privroot_deh(inode, deh))
175                                         continue;
176 
177                                 ctx->pos = deh_offset(deh);
178                                 d_ino = deh_objectid(deh);
179                                 if (d_reclen <= 32) {
180                                         local_buf = small_buf;
181                                 } else {
182                                         local_buf = kmalloc(d_reclen,
183                                                             GFP_NOFS);
184                                         if (!local_buf) {
185                                                 pathrelse(&path_to_entry);
186                                                 ret = -ENOMEM;
187                                                 goto out;
188                                         }
189                                         if (item_moved(&tmp_ih, &path_to_entry)) {
190                                                 kfree(local_buf);
191                                                 goto research;
192                                         }
193                                 }
194 
195                                 /*
196                                  * Note, that we copy name to user space via
197                                  * temporary buffer (local_buf) because
198                                  * filldir will block if user space buffer is
199                                  * swapped out. At that time entry can move to
200                                  * somewhere else
201                                  */
202                                 memcpy(local_buf, d_name, d_reclen);
203 
204                                 /*
205                                  * Since filldir might sleep, we can release
206                                  * the write lock here for other waiters
207                                  */
208                                 depth = reiserfs_write_unlock_nested(inode->i_sb);
209                                 if (!dir_emit
210                                     (ctx, local_buf, d_reclen, d_ino,
211                                      DT_UNKNOWN)) {
212                                         reiserfs_write_lock_nested(inode->i_sb, depth);
213                                         if (local_buf != small_buf) {
214                                                 kfree(local_buf);
215                                         }
216                                         goto end;
217                                 }
218                                 reiserfs_write_lock_nested(inode->i_sb, depth);
219                                 if (local_buf != small_buf) {
220                                         kfree(local_buf);
221                                 }
222 
223                                 /* deh_offset(deh) may be invalid now. */
224                                 next_pos = cur_pos + 1;
225 
226                                 if (item_moved(&tmp_ih, &path_to_entry)) {
227                                         set_cpu_key_k_offset(&pos_key,
228                                                              next_pos);
229                                         goto research;
230                                 }
231                         }       /* for */
232                 }
233 
234                 /* end of directory has been reached */
235                 if (item_num != B_NR_ITEMS(bh) - 1)
236                         goto end;
237 
238                 /*
239                  * item we went through is last item of node. Using right
240                  * delimiting key check is it directory end
241                  */
242                 rkey = get_rkey(&path_to_entry, inode->i_sb);
243                 if (!comp_le_keys(rkey, &MIN_KEY)) {
244                         /*
245                          * set pos_key to key, that is the smallest and greater
246                          * that key of the last entry in the item
247                          */
248                         set_cpu_key_k_offset(&pos_key, next_pos);
249                         continue;
250                 }
251 
252                 /* end of directory has been reached */
253                 if (COMP_SHORT_KEYS(rkey, &pos_key)) {
254                         goto end;
255                 }
256 
257                 /* directory continues in the right neighboring block */
258                 set_cpu_key_k_offset(&pos_key,
259                                      le_key_k_offset(KEY_FORMAT_3_5, rkey));
260 
261         }                       /* while */
262 
263 end:
264         ctx->pos = next_pos;
265         pathrelse(&path_to_entry);
266         reiserfs_check_path(&path_to_entry);
267 out:
268         reiserfs_write_unlock(inode->i_sb);
269         return ret;
270 }
271 
272 static int reiserfs_readdir(struct file *file, struct dir_context *ctx)
273 {
274         return reiserfs_readdir_inode(file_inode(file), ctx);
275 }
276 
277 /*
278  * compose directory item containing "." and ".." entries (entries are
279  * not aligned to 4 byte boundary)
280  */
281 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
282                             __le32 par_dirid, __le32 par_objid)
283 {
284         struct reiserfs_de_head *dot, *dotdot;
285 
286         memset(body, 0, EMPTY_DIR_SIZE_V1);
287         dot = (struct reiserfs_de_head *)body;
288         dotdot = dot + 1;
289 
290         /* direntry header of "." */
291         put_deh_offset(dot, DOT_OFFSET);
292         /* these two are from make_le_item_head, and are are LE */
293         dot->deh_dir_id = dirid;
294         dot->deh_objectid = objid;
295         dot->deh_state = 0;     /* Endian safe if 0 */
296         put_deh_location(dot, EMPTY_DIR_SIZE_V1 - strlen("."));
297         mark_de_visible(dot);
298 
299         /* direntry header of ".." */
300         put_deh_offset(dotdot, DOT_DOT_OFFSET);
301         /* key of ".." for the root directory */
302         /* these two are from the inode, and are are LE */
303         dotdot->deh_dir_id = par_dirid;
304         dotdot->deh_objectid = par_objid;
305         dotdot->deh_state = 0;  /* Endian safe if 0 */
306         put_deh_location(dotdot, deh_location(dot) - strlen(".."));
307         mark_de_visible(dotdot);
308 
309         /* copy ".." and "." */
310         memcpy(body + deh_location(dot), ".", 1);
311         memcpy(body + deh_location(dotdot), "..", 2);
312 }
313 
314 /* compose directory item containing "." and ".." entries */
315 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
316                          __le32 par_dirid, __le32 par_objid)
317 {
318         struct reiserfs_de_head *dot, *dotdot;
319 
320         memset(body, 0, EMPTY_DIR_SIZE);
321         dot = (struct reiserfs_de_head *)body;
322         dotdot = dot + 1;
323 
324         /* direntry header of "." */
325         put_deh_offset(dot, DOT_OFFSET);
326         /* these two are from make_le_item_head, and are are LE */
327         dot->deh_dir_id = dirid;
328         dot->deh_objectid = objid;
329         dot->deh_state = 0;     /* Endian safe if 0 */
330         put_deh_location(dot, EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
331         mark_de_visible(dot);
332 
333         /* direntry header of ".." */
334         put_deh_offset(dotdot, DOT_DOT_OFFSET);
335         /* key of ".." for the root directory */
336         /* these two are from the inode, and are are LE */
337         dotdot->deh_dir_id = par_dirid;
338         dotdot->deh_objectid = par_objid;
339         dotdot->deh_state = 0;  /* Endian safe if 0 */
340         put_deh_location(dotdot, deh_location(dot) - ROUND_UP(strlen("..")));
341         mark_de_visible(dotdot);
342 
343         /* copy ".." and "." */
344         memcpy(body + deh_location(dot), ".", 1);
345         memcpy(body + deh_location(dotdot), "..", 2);
346 }
347 

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