dir.c revision cf776a7a4dafa330dd371a6a301ddf9e38747d93 
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
14extern const struct reiserfs_key MIN_KEY;
15
16static int reiserfs_readdir(struct file *, struct dir_context *);
17static int reiserfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
18			      int datasync);
19
20const struct file_operations reiserfs_dir_operations = {
21	.llseek = generic_file_llseek,
22	.read = generic_read_dir,
23	.iterate = 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
31static 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
53static 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 (privroot->d_inode &&
57	        deh->deh_objectid == INODE_PKEY(privroot->d_inode)->k_objectid);
58}
59
60int 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) {
92research:
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
263end:
264	ctx->pos = next_pos;
265	pathrelse(&path_to_entry);
266	reiserfs_check_path(&path_to_entry);
267out:
268	reiserfs_write_unlock(inode->i_sb);
269	return ret;
270}
271
272static 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 */
281void 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 */
315void 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