xref: /openbmc/linux/fs/reiserfs/dir.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 <linux/reiserfs_fs.h>
9 #include <linux/stat.h>
10 #include <linux/buffer_head.h>
11 #include <asm/uaccess.h>
12 
13 extern struct reiserfs_key MIN_KEY;
14 
15 static int reiserfs_readdir(struct file *, void *, filldir_t);
16 static int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry,
17 			      int datasync);
18 
19 const struct file_operations reiserfs_dir_operations = {
20 	.read = generic_read_dir,
21 	.readdir = reiserfs_readdir,
22 	.fsync = reiserfs_dir_fsync,
23 	.ioctl = reiserfs_ioctl,
24 #ifdef CONFIG_COMPAT
25 	.compat_ioctl = reiserfs_compat_ioctl,
26 #endif
27 };
28 
29 static int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry,
30 			      int datasync)
31 {
32 	struct inode *inode = dentry->d_inode;
33 	int err;
34 	reiserfs_write_lock(inode->i_sb);
35 	err = reiserfs_commit_for_inode(inode);
36 	reiserfs_write_unlock(inode->i_sb);
37 	if (err < 0)
38 		return err;
39 	return 0;
40 }
41 
42 #define store_ih(where,what) copy_item_head (where, what)
43 
44 //
45 static int reiserfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
46 {
47 	struct inode *inode = filp->f_path.dentry->d_inode;
48 	struct cpu_key pos_key;	/* key of current position in the directory (key of directory entry) */
49 	INITIALIZE_PATH(path_to_entry);
50 	struct buffer_head *bh;
51 	int item_num, entry_num;
52 	const struct reiserfs_key *rkey;
53 	struct item_head *ih, tmp_ih;
54 	int search_res;
55 	char *local_buf;
56 	loff_t next_pos;
57 	char small_buf[32];	/* avoid kmalloc if we can */
58 	struct reiserfs_dir_entry de;
59 	int ret = 0;
60 
61 	reiserfs_write_lock(inode->i_sb);
62 
63 	reiserfs_check_lock_depth(inode->i_sb, "readdir");
64 
65 	/* form key for search the next directory entry using f_pos field of
66 	   file structure */
67 	make_cpu_key(&pos_key, inode,
68 		     (filp->f_pos) ? (filp->f_pos) : DOT_OFFSET, TYPE_DIRENTRY,
69 		     3);
70 	next_pos = cpu_key_k_offset(&pos_key);
71 
72 	/*  reiserfs_warning (inode->i_sb, "reiserfs_readdir 1: f_pos = %Ld", filp->f_pos); */
73 
74 	path_to_entry.reada = PATH_READA;
75 	while (1) {
76 	      research:
77 		/* search the directory item, containing entry with specified key */
78 		search_res =
79 		    search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
80 					&de);
81 		if (search_res == IO_ERROR) {
82 			// FIXME: we could just skip part of directory which could
83 			// not be read
84 			ret = -EIO;
85 			goto out;
86 		}
87 		entry_num = de.de_entry_num;
88 		bh = de.de_bh;
89 		item_num = de.de_item_num;
90 		ih = de.de_ih;
91 		store_ih(&tmp_ih, ih);
92 
93 		/* we must have found item, that is item of this directory, */
94 		RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
95 		       "vs-9000: found item %h does not match to dir we readdir %K",
96 		       ih, &pos_key);
97 		RFALSE(item_num > B_NR_ITEMS(bh) - 1,
98 		       "vs-9005 item_num == %d, item amount == %d",
99 		       item_num, B_NR_ITEMS(bh));
100 
101 		/* and entry must be not more than number of entries in the item */
102 		RFALSE(I_ENTRY_COUNT(ih) < entry_num,
103 		       "vs-9010: entry number is too big %d (%d)",
104 		       entry_num, I_ENTRY_COUNT(ih));
105 
106 		if (search_res == POSITION_FOUND
107 		    || entry_num < I_ENTRY_COUNT(ih)) {
108 			/* go through all entries in the directory item beginning from the entry, that has been found */
109 			struct reiserfs_de_head *deh =
110 			    B_I_DEH(bh, ih) + entry_num;
111 
112 			for (; entry_num < I_ENTRY_COUNT(ih);
113 			     entry_num++, deh++) {
114 				int d_reclen;
115 				char *d_name;
116 				off_t d_off;
117 				ino_t d_ino;
118 
119 				if (!de_visible(deh))
120 					/* it is hidden entry */
121 					continue;
122 				d_reclen = entry_length(bh, ih, entry_num);
123 				d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
124 				if (!d_name[d_reclen - 1])
125 					d_reclen = strlen(d_name);
126 
127 				if (d_reclen >
128 				    REISERFS_MAX_NAME(inode->i_sb->
129 						      s_blocksize)) {
130 					/* too big to send back to VFS */
131 					continue;
132 				}
133 
134 				/* Ignore the .reiserfs_priv entry */
135 				if (reiserfs_xattrs(inode->i_sb) &&
136 				    !old_format_only(inode->i_sb) &&
137 				    filp->f_path.dentry == inode->i_sb->s_root &&
138 				    REISERFS_SB(inode->i_sb)->priv_root &&
139 				    REISERFS_SB(inode->i_sb)->priv_root->d_inode
140 				    && deh_objectid(deh) ==
141 				    le32_to_cpu(INODE_PKEY
142 						(REISERFS_SB(inode->i_sb)->
143 						 priv_root->d_inode)->
144 						k_objectid)) {
145 					continue;
146 				}
147 
148 				d_off = deh_offset(deh);
149 				filp->f_pos = d_off;
150 				d_ino = deh_objectid(deh);
151 				if (d_reclen <= 32) {
152 					local_buf = small_buf;
153 				} else {
154 					local_buf = kmalloc(d_reclen,
155 							    GFP_NOFS);
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 						kfree(local_buf);
163 						goto research;
164 					}
165 				}
166 				// Note, that we copy name to user space via temporary
167 				// buffer (local_buf) because filldir will block if
168 				// user space buffer is swapped out. At that time
169 				// entry can move to somewhere else
170 				memcpy(local_buf, d_name, d_reclen);
171 				if (filldir
172 				    (dirent, local_buf, d_reclen, d_off, d_ino,
173 				     DT_UNKNOWN) < 0) {
174 					if (local_buf != small_buf) {
175 						kfree(local_buf);
176 					}
177 					goto end;
178 				}
179 				if (local_buf != small_buf) {
180 					kfree(local_buf);
181 				}
182 				// next entry should be looked for with such offset
183 				next_pos = deh_offset(deh) + 1;
184 
185 				if (item_moved(&tmp_ih, &path_to_entry)) {
186 					goto research;
187 				}
188 			}	/* for */
189 		}
190 
191 		if (item_num != B_NR_ITEMS(bh) - 1)
192 			// end of directory has been reached
193 			goto end;
194 
195 		/* item we went through is last item of node. Using right
196 		   delimiting key check is it directory end */
197 		rkey = get_rkey(&path_to_entry, inode->i_sb);
198 		if (!comp_le_keys(rkey, &MIN_KEY)) {
199 			/* set pos_key to key, that is the smallest and greater
200 			   that key of the last entry in the item */
201 			set_cpu_key_k_offset(&pos_key, next_pos);
202 			continue;
203 		}
204 
205 		if (COMP_SHORT_KEYS(rkey, &pos_key)) {
206 			// end of directory has been reached
207 			goto end;
208 		}
209 
210 		/* directory continues in the right neighboring block */
211 		set_cpu_key_k_offset(&pos_key,
212 				     le_key_k_offset(KEY_FORMAT_3_5, rkey));
213 
214 	}			/* while */
215 
216       end:
217 	filp->f_pos = next_pos;
218 	pathrelse(&path_to_entry);
219 	reiserfs_check_path(&path_to_entry);
220       out:
221 	reiserfs_write_unlock(inode->i_sb);
222 	return ret;
223 }
224 
225 /* compose directory item containing "." and ".." entries (entries are
226    not aligned to 4 byte boundary) */
227 /* the last four params are LE */
228 void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
229 			    __le32 par_dirid, __le32 par_objid)
230 {
231 	struct reiserfs_de_head *deh;
232 
233 	memset(body, 0, EMPTY_DIR_SIZE_V1);
234 	deh = (struct reiserfs_de_head *)body;
235 
236 	/* direntry header of "." */
237 	put_deh_offset(&(deh[0]), DOT_OFFSET);
238 	/* these two are from make_le_item_head, and are are LE */
239 	deh[0].deh_dir_id = dirid;
240 	deh[0].deh_objectid = objid;
241 	deh[0].deh_state = 0;	/* Endian safe if 0 */
242 	put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
243 	mark_de_visible(&(deh[0]));
244 
245 	/* direntry header of ".." */
246 	put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
247 	/* key of ".." for the root directory */
248 	/* these two are from the inode, and are are LE */
249 	deh[1].deh_dir_id = par_dirid;
250 	deh[1].deh_objectid = par_objid;
251 	deh[1].deh_state = 0;	/* Endian safe if 0 */
252 	put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
253 	mark_de_visible(&(deh[1]));
254 
255 	/* copy ".." and "." */
256 	memcpy(body + deh_location(&(deh[0])), ".", 1);
257 	memcpy(body + deh_location(&(deh[1])), "..", 2);
258 }
259 
260 /* compose directory item containing "." and ".." entries */
261 void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
262 			 __le32 par_dirid, __le32 par_objid)
263 {
264 	struct reiserfs_de_head *deh;
265 
266 	memset(body, 0, EMPTY_DIR_SIZE);
267 	deh = (struct reiserfs_de_head *)body;
268 
269 	/* direntry header of "." */
270 	put_deh_offset(&(deh[0]), DOT_OFFSET);
271 	/* these two are from make_le_item_head, and are are LE */
272 	deh[0].deh_dir_id = dirid;
273 	deh[0].deh_objectid = objid;
274 	deh[0].deh_state = 0;	/* Endian safe if 0 */
275 	put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
276 	mark_de_visible(&(deh[0]));
277 
278 	/* direntry header of ".." */
279 	put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
280 	/* key of ".." for the root directory */
281 	/* these two are from the inode, and are are LE */
282 	deh[1].deh_dir_id = par_dirid;
283 	deh[1].deh_objectid = par_objid;
284 	deh[1].deh_state = 0;	/* Endian safe if 0 */
285 	put_deh_location(&(deh[1]),
286 			 deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
287 	mark_de_visible(&(deh[1]));
288 
289 	/* copy ".." and "." */
290 	memcpy(body + deh_location(&(deh[0])), ".", 1);
291 	memcpy(body + deh_location(&(deh[1])), "..", 2);
292 }
293