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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 
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);
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 
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 */
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 */
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 }