fs/ubifs/misc.h

   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  42  * ubifs_zn_obsolete - check if znode is obsolete.
  43  * @znode: znode to check
  44  *
  45  * This helper function returns %1 if @znode is obsolete and %0 otherwise.
  46  */
  47 static inline int ubifs_zn_obsolete(const struct ubifs_znode *znode)
  48 {
  49         return !!test_bit(OBSOLETE_ZNODE, &znode->flags);
  50 }
  51
  52 /**
  53  * ubifs_zn_cow - check if znode has to be copied on write.
  54  * @znode: znode to check
  55  *
  56  * This helper function returns %1 if @znode is has COW flag set and %0
  57  * otherwise.
  58  */
  59 static inline int ubifs_zn_cow(const struct ubifs_znode *znode)
  60 {
  61         return !!test_bit(COW_ZNODE, &znode->flags);
  62 }
  63
  64 /**
  65  * ubifs_wake_up_bgt - wake up background thread.
  66  * @c: UBIFS file-system description object
  67  */
  68 static inline void ubifs_wake_up_bgt(struct ubifs_info *c)
  69 {
  70         if (c->bgt && !c->need_bgt) {
  71                 c->need_bgt = 1;
  72                 wake_up_process(c->bgt);
  73         }
  74 }
  75
  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
  80  *
  81  * This helper function looks for znode child starting at index @start. Returns
  82  * the child or %NULL if no children were found.
  83  */
  84 static inline struct ubifs_znode *
  85 ubifs_tnc_find_child(struct ubifs_znode *znode, int start)
  86 {
  87         while (start < znode->child_cnt) {
  88                 if (znode->zbranch[start].znode)
  89                         return znode->zbranch[start].znode;
  90                 start += 1;
  91         }
  92
  93         return NULL;
  94 }
  95
  96 /**
  97  * ubifs_inode - get UBIFS inode information by VFS 'struct inode' object.
  98  * @inode: the VFS 'struct inode' pointer
  99  */
 100 static inline struct ubifs_inode *ubifs_inode(const struct inode *inode)
 101 {
 102         return container_of(inode, struct ubifs_inode, vfs_inode);
 103 }
 104
 105 /**
 106  * ubifs_compr_present - check if compressor was compiled in.
 107  * @compr_type: compressor type to check
 108  * @c: the UBIFS file-system description object
 109  *
 110  * This function returns %1 of compressor of type @compr_type is present, and
 111  * %0 if not.
 112  */
 113 static inline int ubifs_compr_present(struct ubifs_info *c, int compr_type)
 114 {
 115         ubifs_assert(c, compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
 116         return !!ubifs_compressors[compr_type]->capi_name;
 117 }
 118
 119 /**
 120  * ubifs_compr_name - get compressor name string by its type.
 121  * @compr_type: compressor type
 122  * @c: the UBIFS file-system description object
 123  *
 124  * This function returns compressor type string.
 125  */
 126 static inline const char *ubifs_compr_name(struct ubifs_info *c, int compr_type)
 127 {
 128         ubifs_assert(c, compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
 129         return ubifs_compressors[compr_type]->name;
 130 }
 131
 132 /**
 133  * ubifs_wbuf_sync - synchronize write-buffer.
 134  * @wbuf: write-buffer to synchronize
 135  *
 136  * This is the same as as 'ubifs_wbuf_sync_nolock()' but it does not assume
 137  * that the write-buffer is already locked.
 138  */
 139 static inline int ubifs_wbuf_sync(struct ubifs_wbuf *wbuf)
 140 {
 141         int err;
 142
 143         mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
 144         err = ubifs_wbuf_sync_nolock(wbuf);
 145         mutex_unlock(&wbuf->io_mutex);
 146         return err;
 147 }
 148
 149 /**
 150  * ubifs_encode_dev - encode device node IDs.
 151  * @dev: UBIFS device node information
 152  * @rdev: device IDs to encode
 153  *
 154  * This is a helper function which encodes major/minor numbers of a device node
 155  * into UBIFS device node description. We use standard Linux "new" and "huge"
 156  * encodings.
 157  */
 158 static inline int ubifs_encode_dev(union ubifs_dev_desc *dev, dev_t rdev)
 159 {
 160         dev->new = cpu_to_le32(new_encode_dev(rdev));
 161         return sizeof(dev->new);
 162 }
 163
 164 /**
 165  * ubifs_add_dirt - add dirty space to LEB properties.
 166  * @c: the UBIFS file-system description object
 167  * @lnum: LEB to add dirty space for
 168  * @dirty: dirty space to add
 169  *
 170  * This is a helper function which increased amount of dirty LEB space. Returns
 171  * zero in case of success and a negative error code in case of failure.
 172  */
 173 static inline int ubifs_add_dirt(struct ubifs_info *c, int lnum, int dirty)
 174 {
 175         return ubifs_update_one_lp(c, lnum, LPROPS_NC, dirty, 0, 0);
 176 }
 177
 178 /**
 179  * ubifs_return_leb - return LEB to lprops.
 180  * @c: the UBIFS file-system description object
 181  * @lnum: LEB to return
 182  *
 183  * This helper function cleans the "taken" flag of a logical eraseblock in the
 184  * lprops. Returns zero in case of success and a negative error code in case of
 185  * failure.
 186  */
 187 static inline int ubifs_return_leb(struct ubifs_info *c, int lnum)
 188 {
 189         return ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
 190                                    LPROPS_TAKEN, 0);
 191 }
 192
 193 /**
 194  * ubifs_idx_node_sz - return index node size.
 195  * @c: the UBIFS file-system description object
 196  * @child_cnt: number of children of this index node
 197  */
 198 static inline int ubifs_idx_node_sz(const struct ubifs_info *c, int child_cnt)
 199 {
 200         return UBIFS_IDX_NODE_SZ + (UBIFS_BRANCH_SZ + c->key_len + c->hash_len)
 201                                    * child_cnt;
 202 }
 203
 204 /**
 205  * ubifs_idx_branch - return pointer to an index branch.
 206  * @c: the UBIFS file-system description object
 207  * @idx: index node
 208  * @bnum: branch number
 209  */
 210 static inline
 211 struct ubifs_branch *ubifs_idx_branch(const struct ubifs_info *c,
 212                                       const struct ubifs_idx_node *idx,
 213                                       int bnum)
 214 {
 215         return (struct ubifs_branch *)((void *)idx->branches +
 216                         (UBIFS_BRANCH_SZ + c->key_len + c->hash_len) * bnum);
 217 }
 218
 219 /**
 220  * ubifs_idx_key - return pointer to an index key.
 221  * @c: the UBIFS file-system description object
 222  * @idx: index node
 223  */
 224 static inline void *ubifs_idx_key(const struct ubifs_info *c,
 225                                   const struct ubifs_idx_node *idx)
 226 {
 227         return (void *)((struct ubifs_branch *)idx->branches)->key;
 228 }
 229
 230 /**
 231  * ubifs_tnc_lookup - look up a file-system node.
 232  * @c: UBIFS file-system description object
 233  * @key: node key to lookup
 234  * @node: the node is returned here
 235  *
 236  * This function look up and reads node with key @key. The caller has to make
 237  * sure the @node buffer is large enough to fit the node. Returns zero in case
 238  * of success, %-ENOENT if the node was not found, and a negative error code in
 239  * case of failure.
 240  */
 241 static inline int ubifs_tnc_lookup(struct ubifs_info *c,
 242                                    const union ubifs_key *key, void *node)
 243 {
 244         return ubifs_tnc_locate(c, key, node, NULL, NULL);
 245 }
 246
 247 /**
 248  * ubifs_get_lprops - get reference to LEB properties.
 249  * @c: the UBIFS file-system description object
 250  *
 251  * This function locks lprops. Lprops have to be unlocked by
 252  * 'ubifs_release_lprops()'.
 253  */
 254 static inline void ubifs_get_lprops(struct ubifs_info *c)
 255 {
 256         mutex_lock(&c->lp_mutex);
 257 }
 258
 259 /**
 260  * ubifs_release_lprops - release lprops lock.
 261  * @c: the UBIFS file-system description object
 262  *
 263  * This function has to be called after each 'ubifs_get_lprops()' call to
 264  * unlock lprops.
 265  */
 266 static inline void ubifs_release_lprops(struct ubifs_info *c)
 267 {
 268         ubifs_assert(c, mutex_is_locked(&c->lp_mutex));
 269         ubifs_assert(c, c->lst.empty_lebs >= 0 &&
 270                      c->lst.empty_lebs <= c->main_lebs);
 271         mutex_unlock(&c->lp_mutex);
 272 }
 273
 274 /**
 275  * ubifs_next_log_lnum - switch to the next log LEB.
 276  * @c: UBIFS file-system description object
 277  * @lnum: current log LEB
 278  *
 279  * This helper function returns the log LEB number which goes next after LEB
 280  * 'lnum'.
 281  */
 282 static inline int ubifs_next_log_lnum(const struct ubifs_info *c, int lnum)
 283 {
 284         lnum += 1;
 285         if (lnum > c->log_last)
 286                 lnum = UBIFS_LOG_LNUM;
 287
 288         return lnum;
 289 }
 290
 291 const char *ubifs_assert_action_name(struct ubifs_info *c);
 292
 293 #endif /* __UBIFS_MISC_H__ */