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  42  * ubifs_zn_obsolete - check if znode is obsolete.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  45  * This helper function returns %1 if @znode is obsolete and %0 otherwise.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  *
 109  * This function returns %1 of compressor of type @compr_type is present, and
 110  * %0 if not.
 111  */
 112 static inline int ubifs_compr_present(int compr_type)
 113 {
 114         ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
 115         return !!ubifs_compressors[compr_type]->capi_name;
 116 }
 117
 118 /**
 119  * ubifs_compr_name - get compressor name string by its type.
 120  * @compr_type: compressor type
 121  *
 122  * This function returns compressor type string.
 123  */
 124 static inline const char *ubifs_compr_name(int compr_type)
 125 {
 126         ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
 127         return ubifs_compressors[compr_type]->name;
 128 }
 129
 130 /**
 131  * ubifs_wbuf_sync - synchronize write-buffer.
 132  * @wbuf: write-buffer to synchronize
 133  *
 134  * This is the same as as 'ubifs_wbuf_sync_nolock()' but it does not assume
 135  * that the write-buffer is already locked.
 136  */
 137 static inline int ubifs_wbuf_sync(struct ubifs_wbuf *wbuf)
 138 {
 139         int err;
 140
 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;
 145 }
 146
 147 /**
 148  * ubifs_encode_dev - encode device node IDs.
 149  * @dev: UBIFS device node information
 150  * @rdev: device IDs to encode
 151  *
 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.
 155  */
 156 static inline int ubifs_encode_dev(union ubifs_dev_desc *dev, dev_t rdev)
 157 {
 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);
 164         }
 165 }
 166
 167 /**
 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
 172  *
 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.
 175  */
 176 static inline int ubifs_add_dirt(struct ubifs_info *c, int lnum, int dirty)
 177 {
 178         return ubifs_update_one_lp(c, lnum, LPROPS_NC, dirty, 0, 0);
 179 }
 180
 181 /**
 182  * ubifs_return_leb - return LEB to lprops.
 183  * @c: the UBIFS file-system description object
 184  * @lnum: LEB to return
 185  *
 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.
 189  */
 190 static inline int ubifs_return_leb(struct ubifs_info *c, int lnum)
 191 {
 192         return ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
 193                                    LPROPS_TAKEN, 0);
 194 }
 195
 196 /**
 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
 200  */
 201 static inline int ubifs_idx_node_sz(const struct ubifs_info *c, int child_cnt)
 202 {
 203         return UBIFS_IDX_NODE_SZ + (UBIFS_BRANCH_SZ + c->key_len) * child_cnt;
 204 }
 205
 206 /**
 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
 211  */
 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)
 216 {
 217         return (struct ubifs_branch *)((void *)idx->branches +
 218                                        (UBIFS_BRANCH_SZ + c->key_len) * bnum);
 219 }
 220
 221 /**
 222  * ubifs_idx_key - return pointer to an index key.
 223  * @c: the UBIFS file-system description object
 224  * @idx: index node
 225  */
 226 static inline void *ubifs_idx_key(const struct ubifs_info *c,
 227                                   const struct ubifs_idx_node *idx)
 228 {
 229         return (void *)((struct ubifs_branch *)idx->branches)->key;
 230 }
 231
 232 /**
 233  * ubifs_current_time - round current time to time granularity.
 234  * @inode: inode
 235  */
 236 static inline struct timespec ubifs_current_time(struct inode *inode)
 237 {
 238         return (inode->i_sb->s_time_gran < NSEC_PER_SEC) ?
 239                 current_fs_time(inode->i_sb) : CURRENT_TIME_SEC;
 240 }
 241
 242 /**
 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
 247  *
 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.
 252  */
 253 static inline int ubifs_tnc_lookup(struct ubifs_info *c,
 254                                    const union ubifs_key *key, void *node)
 255 {
 256         return ubifs_tnc_locate(c, key, node, NULL, NULL);
 257 }
 258
 259 /**
 260  * ubifs_get_lprops - get reference to LEB properties.
 261  * @c: the UBIFS file-system description object
 262  *
 263  * This function locks lprops. Lprops have to be unlocked by
 264  * 'ubifs_release_lprops()'.
 265  */
 266 static inline void ubifs_get_lprops(struct ubifs_info *c)
 267 {
 268         mutex_lock(&c->lp_mutex);
 269 }
 270
 271 /**
 272  * ubifs_release_lprops - release lprops lock.
 273  * @c: the UBIFS file-system description object
 274  *
 275  * This function has to be called after each 'ubifs_get_lprops()' call to
 276  * unlock lprops.
 277  */
 278 static inline void ubifs_release_lprops(struct ubifs_info *c)
 279 {
 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);
 284 }
 285
 286 /**
 287  * ubifs_next_log_lnum - switch to the next log LEB.
 288  * @c: UBIFS file-system description object
 289  * @lnum: current log LEB
 290  *
 291  * This helper function returns the log LEB number which goes next after LEB
 292  * 'lnum'.
 293  */
 294 static inline int ubifs_next_log_lnum(const struct ubifs_info *c, int lnum)
 295 {
 296         lnum += 1;
 297         if (lnum > c->log_last)
 298                 lnum = UBIFS_LOG_LNUM;
 299
 300         return lnum;
 301 }
 302
 303 #endif /* __UBIFS_MISC_H__ */