xref: /openbmc/linux/fs/reiserfs/dir.c (revision f21e49be)
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 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 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 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 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