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_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 /**
 344  * ubifs_next_log_lnum - switch to the next log LEB.
 345  * @c: UBIFS file-system description object
 346  * @lnum: current log LEB
 347  *
 348  * This helper function returns the log LEB number which goes next after LEB
 349  * 'lnum'.
 350  */
 351 static inline int ubifs_next_log_lnum(const struct ubifs_info *c, int lnum)
 352 {
 353         lnum += 1;
 354         if (lnum > c->log_last)
 355                 lnum = UBIFS_LOG_LNUM;
 356
 357         return lnum;
 358 }
 359
 360 #endif /* __UBIFS_MISC_H__ */