xref: /openbmc/linux/fs/reiserfs/dir.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
3  */
4 
5 #include <linux/config.h>
6 #include <linux/string.h>
7 #include <linux/errno.h>
8 #include <linux/fs.h>
9 #include <linux/reiserfs_fs.h>
10 #include <linux/stat.h>
11 #include <linux/smp_lock.h>
12 #include <linux/buffer_head.h>
13 #include <asm/uaccess.h>
14 
15 extern struct reiserfs_key MIN_KEY;
16 
17 static int reiserfs_readdir(struct file *, void *, filldir_t);
18 static int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry,
19 			      int datasync);
20 
21 struct file_operations reiserfs_dir_operations = {
22 	.read = generic_read_dir,
23 	.readdir = reiserfs_readdir,
24 	.fsync = reiserfs_dir_fsync,
25 	.ioctl = reiserfs_ioctl,
26 };
27 
28 static int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry,
29 			      int datasync)
30 {
31 	struct inode *inode = dentry->d_inode;
32 	int err;
33 	reiserfs_write_lock(inode->i_sb);
34 	err = reiserfs_commit_for_inode(inode);
35 	reiserfs_write_unlock(inode->i_sb);
36 	if (err < 0)
37 		return err;
38 	return 0;
39 }
40 
41 #define store_ih(where,what) copy_item_head (where, what)
42 
43 //
44 static int reiserfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
45 {
46 	struct inode *inode = filp->f_dentry->d_inode;
47 	struct cpu_key pos_key;	/* key of current position in the directory (key of directory entry) */
48 	INITIALIZE_PATH(path_to_entry);
49 	struct buffer_head *bh;
50 	int item_num, entry_num;
51 	const struct reiserfs_key *rkey;
52 	struct item_head *ih, tmp_ih;
53 	int search_res;
54 	char *local_buf;
55 	loff_t next_pos;
56 	char small_buf[32];	/* avoid kmalloc if we can */
57 	struct reiserfs_dir_entry de;
58 	int ret = 0;
59 
60 	reiserfs_write_lock(inode->i_sb);
61 
62 	reiserfs_check_lock_depth(inode->i_sb, "readdir");
63 
64 	/* form key for search the next directory entry using f_pos field of
65 	   file structure */
66 	make_cpu_key(&pos_key, inode,
67 		     (filp->f_pos) ? (filp->f_pos) : DOT_OFFSET, TYPE_DIRENTRY,
68 		     3);
69 	next_pos = cpu_key_k_offset(&pos_key);
70 
71 	/*  reiserfs_warning (inode->i_sb, "reiserfs_readdir 1: f_pos = %Ld", filp->f_pos); */
72 
73 	path_to_entry.reada = PATH_READA;
74 	while (1) {
75 	      research:
76 		/* search the directory item, containing entry with specified key */
77 		search_res =
78 		    search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
79 					&de);
80 		if (search_res == IO_ERROR) {
81 			// FIXME: we could just skip part of directory which could
82 			// not be read
83 			ret = -EIO;
84 			goto out;
85 		}
86 		entry_num = de.de_entry_num;
87 		bh = de.de_bh;
88 		item_num = de.de_item_num;
89 		ih = de.de_ih;
90 		store_ih(&tmp_ih, ih);
91 
92 		/* we must have found item, that is item of this directory, */
93 		RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
94 		       "vs-9000: found item %h does not match to dir we readdir %K",
95 		       ih, &pos_key);
96 		RFALSE(item_num > B_NR_ITEMS(bh) - 1,
97 		       "vs-9005 item_num == %d, item amount == %d",
98 		       item_num, B_NR_ITEMS(bh));
99 
100 		/* and entry must be not more than number of entries in the item */
101 		RFALSE(I_ENTRY_COUNT(ih) < entry_num,
102 		       "vs-9010: entry number is too big %d (%d)",
103 		       entry_num, I_ENTRY_COUNT(ih));
104 
105 		if (search_res == POSITION_FOUND
106 		    || entry_num < I_ENTRY_COUNT(ih)) {
107 			/* go through all entries in the directory item beginning from the entry, that has been found */
108 			struct reiserfs_de_head *deh =
109 			    B_I_DEH(bh, ih) + entry_num;
110 
111 			for (; entry_num < I_ENTRY_COUNT(ih);
112 			     entry_num++, deh++) {
113 				int d_reclen;
114 				char *d_name;
115 				off_t d_off;
116 				ino_t d_ino;
117 
118 				if (!de_visible(deh))
119 					/* it is hidden entry */
120 					continue;
121 				d_reclen = entry_length(bh, ih, entry_num);
122 				d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
123 				if (!d_name[d_reclen - 1])
124 					d_reclen = strlen(d_name);
125 
126 				if (d_reclen >
127 				    REISERFS_MAX_NAME(inode->i_sb->
128 						      s_blocksize)) {
129 					/* too big to send back to VFS */
130 					continue;
131 				}
132 
133 				/* Ignore the .reiserfs_priv entry */
134 				if (reiserfs_xattrs(inode->i_sb) &&
135 				    !old_format_only(inode->i_sb) &&
136 				    filp->f_dentry == inode->i_sb->s_root &&
137 				    REISERFS_SB(inode->i_sb)->priv_root &&
138 				    REISERFS_SB(inode->i_sb)->priv_root->d_inode
139 				    && deh_objectid(deh) ==
140 				    le32_to_cpu(INODE_PKEY
141 						(REISERFS_SB(inode->i_sb)->
142 						 priv_root->d_inode)->
143 						k_objectid)) {
144 					continue;
145 				}
146 
147 				d_off = deh_offset(deh);
148 				filp->f_pos = d_off;
149 				d_ino = deh_objectid(deh);
150 				if (d_reclen <= 32) {
151 					local_buf = small_buf;
152 				} else {
153 					local_buf =
154 					    reiserfs_kmalloc(d_reclen, GFP_NOFS,
155 							     inode->i_sb);
156 					if (!local_buf) {
157 						pathrelse(&path_to_entry);
158 						ret = -ENOMEM;
159 						goto out;
160 					}
161 					if (item_moved(&tmp_ih, &path_to_entry)) {
162 						reiserfs_kfree(local_buf,
163 							       d_reclen,
164 							       inode->i_sb);
165 						goto research;
166 					}
167 				}
168 				// Note, that we copy name to user space via temporary
169 				// buffer (local_buf) because filldir will block if
170 				// user space buffer is swapped out. At that time
171 				// entry can move to somewhere else
172 				memcpy(local_buf, d_name, d_reclen);
173 				if (filldir
174 				    (dirent, local_buf, d_reclen, d_off, d_ino,
175 				     DT_UNKNOWN) < 0) {
176 					if (local_buf != small_buf) {
177 						reiserfs_kfree(local_buf,
178 							       d_reclen,
179 							       inode->i_sb);
180 					}
181 					goto end;
182 				}
183 				if (local_buf != small_buf) {
184 					reiserfs_kfree(local_buf, d_reclen,
185 						       inode->i_sb);
186 				}
187 				// next entry should be looked for with such offset
188 				next_pos = deh_offset(deh) + 1;
189 
190 				if (item_moved(&tmp_ih, &path_to_entry)) {
191 					goto research;
192 				}
193 			}	/* for */
194 		}
195 
196 		if (item_num != B_NR_ITEMS(bh) - 1)
197 			// end of directory has been reached
198 			goto end;
199 
200 		/* item we went through is last item of node. Using right
201 		   delimiting key check is it directory end */
202 		rkey = get_rkey(&path_to_entry, inode->i_sb);
203 		if (!comp_le_keys(rkey, &MIN_KEY)) {
204 			/* set pos_key to key, that is the smallest and greater
205 			   that key of the last entry in the item */
206 			set_cpu_key_k_offset(&pos_key, next_pos);
207 			continue;
208 		}
209 
210 		if (COMP_SHORT_KEYS(rkey, &pos_key)) {
211 			// end of directory has been reached
212 			goto end;
213 		}
214 
215 		/* directory continues in the right neighboring block */
216 		set_cpu_key_k_offset(&pos_key,
217 				     le_key_k_offset(KEY_FORMAT_3_5, rkey));
218 
219 	}			/* while */
220 
221       end:
222 	filp->f_pos = next_pos;
223 	pathrelse(&path_to_entry);
224 	reiserfs_check_path(&path_to_entry);
225       out:
226 	reiserfs_write_unlock(inode->i_sb);
227 	return ret;
228 }
229 
230 /* compose directory item containing "." and ".." entries (entries are
231    not aligned to 4 byte boundary) */
232 /* the last four params are LE */
233 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
234 			    __le32 par_dirid, __le32 par_objid)
235 {
236 	struct reiserfs_de_head *deh;
237 
238 	memset(body, 0, EMPTY_DIR_SIZE_V1);
239 	deh = (struct reiserfs_de_head *)body;
240 
241 	/* direntry header of "." */
242 	put_deh_offset(&(deh[0]), DOT_OFFSET);
243 	/* these two are from make_le_item_head, and are are LE */
244 	deh[0].deh_dir_id = dirid;
245 	deh[0].deh_objectid = objid;
246 	deh[0].deh_state = 0;	/* Endian safe if 0 */
247 	put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
248 	mark_de_visible(&(deh[0]));
249 
250 	/* direntry header of ".." */
251 	put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
252 	/* key of ".." for the root directory */
253 	/* these two are from the inode, and are are LE */
254 	deh[1].deh_dir_id = par_dirid;
255 	deh[1].deh_objectid = par_objid;
256 	deh[1].deh_state = 0;	/* Endian safe if 0 */
257 	put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
258 	mark_de_visible(&(deh[1]));
259 
260 	/* copy ".." and "." */
261 	memcpy(body + deh_location(&(deh[0])), ".", 1);
262 	memcpy(body + deh_location(&(deh[1])), "..", 2);
263 }
264 
265 /* compose directory item containing "." and ".." entries */
266 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
267 			 __le32 par_dirid, __le32 par_objid)
268 {
269 	struct reiserfs_de_head *deh;
270 
271 	memset(body, 0, EMPTY_DIR_SIZE);
272 	deh = (struct reiserfs_de_head *)body;
273 
274 	/* direntry header of "." */
275 	put_deh_offset(&(deh[0]), DOT_OFFSET);
276 	/* these two are from make_le_item_head, and are are LE */
277 	deh[0].deh_dir_id = dirid;
278 	deh[0].deh_objectid = objid;
279 	deh[0].deh_state = 0;	/* Endian safe if 0 */
280 	put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
281 	mark_de_visible(&(deh[0]));
282 
283 	/* direntry header of ".." */
284 	put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
285 	/* key of ".." for the root directory */
286 	/* these two are from the inode, and are are LE */
287 	deh[1].deh_dir_id = par_dirid;
288 	deh[1].deh_objectid = par_objid;
289 	deh[1].deh_state = 0;	/* Endian safe if 0 */
290 	put_deh_location(&(deh[1]),
291 			 deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
292 	mark_de_visible(&(deh[1]));
293 
294 	/* copy ".." and "." */
295 	memcpy(body + deh_location(&(deh[0])), ".", 1);
296 	memcpy(body + deh_location(&(deh[1])), "..", 2);
297 }
298