dm mpath: check if scsi_dh module already loaded before trying to load
[zen-stable.git] / fs / ubifs / misc.h
blobee7cb5ebb6e8910f851469bce4dcb205785cb85c
1 /*
2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation
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.
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.
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
19 * Authors: Artem Bityutskiy (Битюцкий Артём)
20 * Adrian Hunter
24 * This file contains miscellaneous helper functions.
27 #ifndef __UBIFS_MISC_H__
28 #define __UBIFS_MISC_H__
30 /**
31 * ubifs_zn_dirty - check if znode is dirty.
32 * @znode: znode to check
34 * This helper function returns %1 if @znode is dirty and %0 otherwise.
36 static inline int ubifs_zn_dirty(const struct ubifs_znode *znode)
38 return !!test_bit(DIRTY_ZNODE, &znode->flags);
41 /**
42 * ubifs_zn_obsolete - check if znode is obsolete.
43 * @znode: znode to check
45 * This helper function returns %1 if @znode is obsolete and %0 otherwise.
47 static inline int ubifs_zn_obsolete(const struct ubifs_znode *znode)
49 return !!test_bit(OBSOLETE_ZNODE, &znode->flags);
52 /**
53 * ubifs_zn_cow - check if znode has to be copied on write.
54 * @znode: znode to check
56 * This helper function returns %1 if @znode is has COW flag set and %0
57 * otherwise.
59 static inline int ubifs_zn_cow(const struct ubifs_znode *znode)
61 return !!test_bit(COW_ZNODE, &znode->flags);
64 /**
65 * ubifs_wake_up_bgt - wake up background thread.
66 * @c: UBIFS file-system description object
68 static inline void ubifs_wake_up_bgt(struct ubifs_info *c)
70 if (c->bgt && !c->need_bgt) {
71 c->need_bgt = 1;
72 wake_up_process(c->bgt);
76 /**
77 * ubifs_tnc_find_child - find next child in znode.
78 * @znode: znode to search at
79 * @start: the zbranch index to start at
81 * This helper function looks for znode child starting at index @start. Returns
82 * the child or %NULL if no children were found.
84 static inline struct ubifs_znode *
85 ubifs_tnc_find_child(struct ubifs_znode *znode, int start)
87 while (start < znode->child_cnt) {
88 if (znode->zbranch[start].znode)
89 return znode->zbranch[start].znode;
90 start += 1;
93 return NULL;
96 /**
97 * ubifs_inode - get UBIFS inode information by VFS 'struct inode' object.
98 * @inode: the VFS 'struct inode' pointer
100 static inline struct ubifs_inode *ubifs_inode(const struct inode *inode)
102 return container_of(inode, struct ubifs_inode, vfs_inode);
106 * ubifs_compr_present - check if compressor was compiled in.
107 * @compr_type: compressor type to check
109 * This function returns %1 of compressor of type @compr_type is present, and
110 * %0 if not.
112 static inline int ubifs_compr_present(int compr_type)
114 ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
115 return !!ubifs_compressors[compr_type]->capi_name;
119 * ubifs_compr_name - get compressor name string by its type.
120 * @compr_type: compressor type
122 * This function returns compressor type string.
124 static inline const char *ubifs_compr_name(int compr_type)
126 ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
127 return ubifs_compressors[compr_type]->name;
131 * ubifs_wbuf_sync - synchronize write-buffer.
132 * @wbuf: write-buffer to synchronize
134 * This is the same as as 'ubifs_wbuf_sync_nolock()' but it does not assume
135 * that the write-buffer is already locked.
137 static inline int ubifs_wbuf_sync(struct ubifs_wbuf *wbuf)
139 int err;
141 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
142 err = ubifs_wbuf_sync_nolock(wbuf);
143 mutex_unlock(&wbuf->io_mutex);
144 return err;
148 * ubifs_encode_dev - encode device node IDs.
149 * @dev: UBIFS device node information
150 * @rdev: device IDs to encode
152 * This is a helper function which encodes major/minor numbers of a device node
153 * into UBIFS device node description. We use standard Linux "new" and "huge"
154 * encodings.
156 static inline int ubifs_encode_dev(union ubifs_dev_desc *dev, dev_t rdev)
158 if (new_valid_dev(rdev)) {
159 dev->new = cpu_to_le32(new_encode_dev(rdev));
160 return sizeof(dev->new);
161 } else {
162 dev->huge = cpu_to_le64(huge_encode_dev(rdev));
163 return sizeof(dev->huge);
168 * ubifs_add_dirt - add dirty space to LEB properties.
169 * @c: the UBIFS file-system description object
170 * @lnum: LEB to add dirty space for
171 * @dirty: dirty space to add
173 * This is a helper function which increased amount of dirty LEB space. Returns
174 * zero in case of success and a negative error code in case of failure.
176 static inline int ubifs_add_dirt(struct ubifs_info *c, int lnum, int dirty)
178 return ubifs_update_one_lp(c, lnum, LPROPS_NC, dirty, 0, 0);
182 * ubifs_return_leb - return LEB to lprops.
183 * @c: the UBIFS file-system description object
184 * @lnum: LEB to return
186 * This helper function cleans the "taken" flag of a logical eraseblock in the
187 * lprops. Returns zero in case of success and a negative error code in case of
188 * failure.
190 static inline int ubifs_return_leb(struct ubifs_info *c, int lnum)
192 return ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
193 LPROPS_TAKEN, 0);
197 * ubifs_idx_node_sz - return index node size.
198 * @c: the UBIFS file-system description object
199 * @child_cnt: number of children of this index node
201 static inline int ubifs_idx_node_sz(const struct ubifs_info *c, int child_cnt)
203 return UBIFS_IDX_NODE_SZ + (UBIFS_BRANCH_SZ + c->key_len) * child_cnt;
207 * ubifs_idx_branch - return pointer to an index branch.
208 * @c: the UBIFS file-system description object
209 * @idx: index node
210 * @bnum: branch number
212 static inline
213 struct ubifs_branch *ubifs_idx_branch(const struct ubifs_info *c,
214 const struct ubifs_idx_node *idx,
215 int bnum)
217 return (struct ubifs_branch *)((void *)idx->branches +
218 (UBIFS_BRANCH_SZ + c->key_len) * bnum);
222 * ubifs_idx_key - return pointer to an index key.
223 * @c: the UBIFS file-system description object
224 * @idx: index node
226 static inline void *ubifs_idx_key(const struct ubifs_info *c,
227 const struct ubifs_idx_node *idx)
229 return (void *)((struct ubifs_branch *)idx->branches)->key;
233 * ubifs_current_time - round current time to time granularity.
234 * @inode: inode
236 static inline struct timespec ubifs_current_time(struct inode *inode)
238 return (inode->i_sb->s_time_gran < NSEC_PER_SEC) ?
239 current_fs_time(inode->i_sb) : CURRENT_TIME_SEC;
243 * ubifs_tnc_lookup - look up a file-system node.
244 * @c: UBIFS file-system description object
245 * @key: node key to lookup
246 * @node: the node is returned here
248 * This function look up and reads node with key @key. The caller has to make
249 * sure the @node buffer is large enough to fit the node. Returns zero in case
250 * of success, %-ENOENT if the node was not found, and a negative error code in
251 * case of failure.
253 static inline int ubifs_tnc_lookup(struct ubifs_info *c,
254 const union ubifs_key *key, void *node)
256 return ubifs_tnc_locate(c, key, node, NULL, NULL);
260 * ubifs_get_lprops - get reference to LEB properties.
261 * @c: the UBIFS file-system description object
263 * This function locks lprops. Lprops have to be unlocked by
264 * 'ubifs_release_lprops()'.
266 static inline void ubifs_get_lprops(struct ubifs_info *c)
268 mutex_lock(&c->lp_mutex);
272 * ubifs_release_lprops - release lprops lock.
273 * @c: the UBIFS file-system description object
275 * This function has to be called after each 'ubifs_get_lprops()' call to
276 * unlock lprops.
278 static inline void ubifs_release_lprops(struct ubifs_info *c)
280 ubifs_assert(mutex_is_locked(&c->lp_mutex));
281 ubifs_assert(c->lst.empty_lebs >= 0 &&
282 c->lst.empty_lebs <= c->main_lebs);
283 mutex_unlock(&c->lp_mutex);
287 * ubifs_next_log_lnum - switch to the next log LEB.
288 * @c: UBIFS file-system description object
289 * @lnum: current log LEB
291 * This helper function returns the log LEB number which goes next after LEB
292 * 'lnum'.
294 static inline int ubifs_next_log_lnum(const struct ubifs_info *c, int lnum)
296 lnum += 1;
297 if (lnum > c->log_last)
298 lnum = UBIFS_LOG_LNUM;
300 return lnum;
303 #endif /* __UBIFS_MISC_H__ */