xref: /openbmc/linux/fs/ubifs/misc.h (revision 25985edc)
1 /*
2  * This file is part of UBIFS.
3  *
4  * Copyright (C) 2006-2008 Nokia Corporation
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License version 2 as published by
8  * the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  *
15  * You should have received a copy of the GNU General Public License along with
16  * this program; if not, write to the Free Software Foundation, Inc., 51
17  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18  *
19  * Authors: Artem Bityutskiy (Битюцкий Артём)
20  *          Adrian Hunter
21  */
22 
23 /*
24  * This file contains miscellaneous helper functions.
25  */
26 
27 #ifndef __UBIFS_MISC_H__
28 #define __UBIFS_MISC_H__
29 
30 /**
31  * ubifs_zn_dirty - check if znode is dirty.
32  * @znode: znode to check
33  *
34  * This helper function returns %1 if @znode is dirty and %0 otherwise.
35  */
36 static inline int ubifs_zn_dirty(const struct ubifs_znode *znode)
37 {
38 	return !!test_bit(DIRTY_ZNODE, &znode->flags);
39 }
40 
41 /**
42  * ubifs_wake_up_bgt - wake up background thread.
43  * @c: UBIFS file-system description object
44  */
45 static inline void ubifs_wake_up_bgt(struct ubifs_info *c)
46 {
47 	if (c->bgt && !c->need_bgt) {
48 		c->need_bgt = 1;
49 		wake_up_process(c->bgt);
50 	}
51 }
52 
53 /**
54  * ubifs_tnc_find_child - find next child in znode.
55  * @znode: znode to search at
56  * @start: the zbranch index to start at
57  *
58  * This helper function looks for znode child starting at index @start. Returns
59  * the child or %NULL if no children were found.
60  */
61 static inline struct ubifs_znode *
62 ubifs_tnc_find_child(struct ubifs_znode *znode, int start)
63 {
64 	while (start < znode->child_cnt) {
65 		if (znode->zbranch[start].znode)
66 			return znode->zbranch[start].znode;
67 		start += 1;
68 	}
69 
70 	return NULL;
71 }
72 
73 /**
74  * ubifs_inode - get UBIFS inode information by VFS 'struct inode' object.
75  * @inode: the VFS 'struct inode' pointer
76  */
77 static inline struct ubifs_inode *ubifs_inode(const struct inode *inode)
78 {
79 	return container_of(inode, struct ubifs_inode, vfs_inode);
80 }
81 
82 /**
83  * ubifs_compr_present - check if compressor was compiled in.
84  * @compr_type: compressor type to check
85  *
86  * This function returns %1 of compressor of type @compr_type is present, and
87  * %0 if not.
88  */
89 static inline int ubifs_compr_present(int compr_type)
90 {
91 	ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
92 	return !!ubifs_compressors[compr_type]->capi_name;
93 }
94 
95 /**
96  * ubifs_compr_name - get compressor name string by its type.
97  * @compr_type: compressor type
98  *
99  * This function returns compressor type string.
100  */
101 static inline const char *ubifs_compr_name(int compr_type)
102 {
103 	ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
104 	return ubifs_compressors[compr_type]->name;
105 }
106 
107 /**
108  * ubifs_wbuf_sync - synchronize write-buffer.
109  * @wbuf: write-buffer to synchronize
110  *
111  * This is the same as as 'ubifs_wbuf_sync_nolock()' but it does not assume
112  * that the write-buffer is already locked.
113  */
114 static inline int ubifs_wbuf_sync(struct ubifs_wbuf *wbuf)
115 {
116 	int err;
117 
118 	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
119 	err = ubifs_wbuf_sync_nolock(wbuf);
120 	mutex_unlock(&wbuf->io_mutex);
121 	return err;
122 }
123 
124 /**
125  * ubifs_leb_unmap - unmap an LEB.
126  * @c: UBIFS file-system description object
127  * @lnum: LEB number to unmap
128  *
129  * This function returns %0 on success and a negative error code on failure.
130  */
131 static inline int ubifs_leb_unmap(const struct ubifs_info *c, int lnum)
132 {
133 	int err;
134 
135 	ubifs_assert(!c->ro_media && !c->ro_mount);
136 	if (c->ro_error)
137 		return -EROFS;
138 	err = ubi_leb_unmap(c->ubi, lnum);
139 	if (err) {
140 		ubifs_err("unmap LEB %d failed, error %d", lnum, err);
141 		return err;
142 	}
143 
144 	return 0;
145 }
146 
147 /**
148  * ubifs_leb_write - write to a LEB.
149  * @c: UBIFS file-system description object
150  * @lnum: LEB number to write
151  * @buf: buffer to write from
152  * @offs: offset within LEB to write to
153  * @len: length to write
154  * @dtype: data type
155  *
156  * This function returns %0 on success and a negative error code on failure.
157  */
158 static inline int ubifs_leb_write(const struct ubifs_info *c, int lnum,
159 				  const void *buf, int offs, int len, int dtype)
160 {
161 	int err;
162 
163 	ubifs_assert(!c->ro_media && !c->ro_mount);
164 	if (c->ro_error)
165 		return -EROFS;
166 	err = ubi_leb_write(c->ubi, lnum, buf, offs, len, dtype);
167 	if (err) {
168 		ubifs_err("writing %d bytes at %d:%d, error %d",
169 			  len, lnum, offs, err);
170 		return err;
171 	}
172 
173 	return 0;
174 }
175 
176 /**
177  * ubifs_leb_change - atomic LEB change.
178  * @c: UBIFS file-system description object
179  * @lnum: LEB number to write
180  * @buf: buffer to write from
181  * @len: length to write
182  * @dtype: data type
183  *
184  * This function returns %0 on success and a negative error code on failure.
185  */
186 static inline int ubifs_leb_change(const struct ubifs_info *c, int lnum,
187 				   const void *buf, int len, int dtype)
188 {
189 	int err;
190 
191 	ubifs_assert(!c->ro_media && !c->ro_mount);
192 	if (c->ro_error)
193 		return -EROFS;
194 	err = ubi_leb_change(c->ubi, lnum, buf, len, dtype);
195 	if (err) {
196 		ubifs_err("changing %d bytes in LEB %d, error %d",
197 			  len, lnum, err);
198 		return err;
199 	}
200 
201 	return 0;
202 }
203 
204 /**
205  * ubifs_encode_dev - encode device node IDs.
206  * @dev: UBIFS device node information
207  * @rdev: device IDs to encode
208  *
209  * This is a helper function which encodes major/minor numbers of a device node
210  * into UBIFS device node description. We use standard Linux "new" and "huge"
211  * encodings.
212  */
213 static inline int ubifs_encode_dev(union ubifs_dev_desc *dev, dev_t rdev)
214 {
215 	if (new_valid_dev(rdev)) {
216 		dev->new = cpu_to_le32(new_encode_dev(rdev));
217 		return sizeof(dev->new);
218 	} else {
219 		dev->huge = cpu_to_le64(huge_encode_dev(rdev));
220 		return sizeof(dev->huge);
221 	}
222 }
223 
224 /**
225  * ubifs_add_dirt - add dirty space to LEB properties.
226  * @c: the UBIFS file-system description object
227  * @lnum: LEB to add dirty space for
228  * @dirty: dirty space to add
229  *
230  * This is a helper function which increased amount of dirty LEB space. Returns
231  * zero in case of success and a negative error code in case of failure.
232  */
233 static inline int ubifs_add_dirt(struct ubifs_info *c, int lnum, int dirty)
234 {
235 	return ubifs_update_one_lp(c, lnum, LPROPS_NC, dirty, 0, 0);
236 }
237 
238 /**
239  * ubifs_return_leb - return LEB to lprops.
240  * @c: the UBIFS file-system description object
241  * @lnum: LEB to return
242  *
243  * This helper function cleans the "taken" flag of a logical eraseblock in the
244  * lprops. Returns zero in case of success and a negative error code in case of
245  * failure.
246  */
247 static inline int ubifs_return_leb(struct ubifs_info *c, int lnum)
248 {
249 	return ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
250 				   LPROPS_TAKEN, 0);
251 }
252 
253 /**
254  * ubifs_idx_node_sz - return index node size.
255  * @c: the UBIFS file-system description object
256  * @child_cnt: number of children of this index node
257  */
258 static inline int ubifs_idx_node_sz(const struct ubifs_info *c, int child_cnt)
259 {
260 	return UBIFS_IDX_NODE_SZ + (UBIFS_BRANCH_SZ + c->key_len) * child_cnt;
261 }
262 
263 /**
264  * ubifs_idx_branch - return pointer to an index branch.
265  * @c: the UBIFS file-system description object
266  * @idx: index node
267  * @bnum: branch number
268  */
269 static inline
270 struct ubifs_branch *ubifs_idx_branch(const struct ubifs_info *c,
271 				      const struct ubifs_idx_node *idx,
272 				      int bnum)
273 {
274 	return (struct ubifs_branch *)((void *)idx->branches +
275 				       (UBIFS_BRANCH_SZ + c->key_len) * bnum);
276 }
277 
278 /**
279  * ubifs_idx_key - return pointer to an index key.
280  * @c: the UBIFS file-system description object
281  * @idx: index node
282  */
283 static inline void *ubifs_idx_key(const struct ubifs_info *c,
284 				  const struct ubifs_idx_node *idx)
285 {
286 	return (void *)((struct ubifs_branch *)idx->branches)->key;
287 }
288 
289 /**
290  * ubifs_current_time - round current time to time granularity.
291  * @inode: inode
292  */
293 static inline struct timespec ubifs_current_time(struct inode *inode)
294 {
295 	return (inode->i_sb->s_time_gran < NSEC_PER_SEC) ?
296 		current_fs_time(inode->i_sb) : CURRENT_TIME_SEC;
297 }
298 
299 /**
300  * ubifs_tnc_lookup - look up a file-system node.
301  * @c: UBIFS file-system description object
302  * @key: node key to lookup
303  * @node: the node is returned here
304  *
305  * This function look up and reads node with key @key. The caller has to make
306  * sure the @node buffer is large enough to fit the node. Returns zero in case
307  * of success, %-ENOENT if the node was not found, and a negative error code in
308  * case of failure.
309  */
310 static inline int ubifs_tnc_lookup(struct ubifs_info *c,
311 				   const union ubifs_key *key, void *node)
312 {
313 	return ubifs_tnc_locate(c, key, node, NULL, NULL);
314 }
315 
316 /**
317  * ubifs_get_lprops - get reference to LEB properties.
318  * @c: the UBIFS file-system description object
319  *
320  * This function locks lprops. Lprops have to be unlocked by
321  * 'ubifs_release_lprops()'.
322  */
323 static inline void ubifs_get_lprops(struct ubifs_info *c)
324 {
325 	mutex_lock(&c->lp_mutex);
326 }
327 
328 /**
329  * ubifs_release_lprops - release lprops lock.
330  * @c: the UBIFS file-system description object
331  *
332  * This function has to be called after each 'ubifs_get_lprops()' call to
333  * unlock lprops.
334  */
335 static inline void ubifs_release_lprops(struct ubifs_info *c)
336 {
337 	ubifs_assert(mutex_is_locked(&c->lp_mutex));
338 	ubifs_assert(c->lst.empty_lebs >= 0 &&
339 		     c->lst.empty_lebs <= c->main_lebs);
340 	mutex_unlock(&c->lp_mutex);
341 }
342 
343 #endif /* __UBIFS_MISC_H__ */
344