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342 lines
9.3 KiB
342 lines
9.3 KiB
/*
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* This file is part of UBIFS.
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*
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* Copyright (C) 2006-2008 Nokia Corporation
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Authors: Artem Bityutskiy (Битюцкий Артём)
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* Adrian Hunter
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*/
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/*
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* This file contains miscellaneous helper functions.
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*/
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#ifndef __UBIFS_MISC_H__
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#define __UBIFS_MISC_H__
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/**
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* ubifs_zn_dirty - check if znode is dirty.
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* @znode: znode to check
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*
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* This helper function returns %1 if @znode is dirty and %0 otherwise.
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*/
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static inline int ubifs_zn_dirty(const struct ubifs_znode *znode)
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{
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return !!test_bit(DIRTY_ZNODE, &znode->flags);
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}
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/**
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* ubifs_wake_up_bgt - wake up background thread.
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* @c: UBIFS file-system description object
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*/
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static inline void ubifs_wake_up_bgt(struct ubifs_info *c)
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{
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if (c->bgt && !c->need_bgt) {
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c->need_bgt = 1;
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wake_up_process(c->bgt);
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}
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}
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/**
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* ubifs_tnc_find_child - find next child in znode.
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* @znode: znode to search at
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* @start: the zbranch index to start at
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*
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* This helper function looks for znode child starting at index @start. Returns
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* the child or %NULL if no children were found.
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*/
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static inline struct ubifs_znode *
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ubifs_tnc_find_child(struct ubifs_znode *znode, int start)
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{
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while (start < znode->child_cnt) {
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if (znode->zbranch[start].znode)
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return znode->zbranch[start].znode;
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start += 1;
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}
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return NULL;
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}
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/**
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* ubifs_inode - get UBIFS inode information by VFS 'struct inode' object.
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* @inode: the VFS 'struct inode' pointer
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*/
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static inline struct ubifs_inode *ubifs_inode(const struct inode *inode)
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{
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return container_of(inode, struct ubifs_inode, vfs_inode);
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}
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/**
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* ubifs_ro_mode - switch UBIFS to read read-only mode.
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* @c: UBIFS file-system description object
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* @err: error code which is the reason of switching to R/O mode
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*/
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static inline void ubifs_ro_mode(struct ubifs_info *c, int err)
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{
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if (!c->ro_media) {
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c->ro_media = 1;
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ubifs_warn("switched to read-only mode, error %d", err);
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dbg_dump_stack();
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}
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}
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/**
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* ubifs_compr_present - check if compressor was compiled in.
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* @compr_type: compressor type to check
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*
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* This function returns %1 of compressor of type @compr_type is present, and
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* %0 if not.
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*/
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static inline int ubifs_compr_present(int compr_type)
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{
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ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
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return !!ubifs_compressors[compr_type]->capi_name;
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}
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/**
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* ubifs_compr_name - get compressor name string by its type.
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* @compr_type: compressor type
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*
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* This function returns compressor type string.
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*/
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static inline const char *ubifs_compr_name(int compr_type)
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{
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ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
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return ubifs_compressors[compr_type]->name;
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}
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/**
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* ubifs_wbuf_sync - synchronize write-buffer.
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* @wbuf: write-buffer to synchronize
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*
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* This is the same as as 'ubifs_wbuf_sync_nolock()' but it does not assume
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* that the write-buffer is already locked.
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*/
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static inline int ubifs_wbuf_sync(struct ubifs_wbuf *wbuf)
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{
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int err;
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mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
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err = ubifs_wbuf_sync_nolock(wbuf);
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mutex_unlock(&wbuf->io_mutex);
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return err;
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}
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/**
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* ubifs_leb_unmap - unmap an LEB.
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* @c: UBIFS file-system description object
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* @lnum: LEB number to unmap
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*
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* This function returns %0 on success and a negative error code on failure.
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*/
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static inline int ubifs_leb_unmap(const struct ubifs_info *c, int lnum)
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{
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int err;
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if (c->ro_media)
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return -EROFS;
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err = ubi_leb_unmap(c->ubi, lnum);
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if (err) {
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ubifs_err("unmap LEB %d failed, error %d", lnum, err);
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return err;
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}
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return 0;
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}
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/**
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* ubifs_leb_write - write to a LEB.
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* @c: UBIFS file-system description object
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* @lnum: LEB number to write
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* @buf: buffer to write from
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* @offs: offset within LEB to write to
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* @len: length to write
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* @dtype: data type
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*
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* This function returns %0 on success and a negative error code on failure.
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*/
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static inline int ubifs_leb_write(const struct ubifs_info *c, int lnum,
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const void *buf, int offs, int len, int dtype)
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{
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int err;
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if (c->ro_media)
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return -EROFS;
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err = ubi_leb_write(c->ubi, lnum, buf, offs, len, dtype);
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if (err) {
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ubifs_err("writing %d bytes at %d:%d, error %d",
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len, lnum, offs, err);
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return err;
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}
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return 0;
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}
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/**
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* ubifs_leb_change - atomic LEB change.
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* @c: UBIFS file-system description object
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* @lnum: LEB number to write
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* @buf: buffer to write from
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* @len: length to write
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* @dtype: data type
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*
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* This function returns %0 on success and a negative error code on failure.
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*/
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static inline int ubifs_leb_change(const struct ubifs_info *c, int lnum,
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const void *buf, int len, int dtype)
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{
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int err;
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if (c->ro_media)
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return -EROFS;
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err = ubi_leb_change(c->ubi, lnum, buf, len, dtype);
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if (err) {
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ubifs_err("changing %d bytes in LEB %d, error %d",
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len, lnum, err);
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return err;
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}
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return 0;
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}
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/**
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* ubifs_encode_dev - encode device node IDs.
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* @dev: UBIFS device node information
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* @rdev: device IDs to encode
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*
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* This is a helper function which encodes major/minor numbers of a device node
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* into UBIFS device node description. We use standard Linux "new" and "huge"
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* encodings.
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*/
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static inline int ubifs_encode_dev(union ubifs_dev_desc *dev, dev_t rdev)
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{
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if (new_valid_dev(rdev)) {
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dev->new = cpu_to_le32(new_encode_dev(rdev));
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return sizeof(dev->new);
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} else {
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dev->huge = cpu_to_le64(huge_encode_dev(rdev));
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return sizeof(dev->huge);
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}
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}
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/**
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* ubifs_add_dirt - add dirty space to LEB properties.
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* @c: the UBIFS file-system description object
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* @lnum: LEB to add dirty space for
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* @dirty: dirty space to add
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*
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* This is a helper function which increased amount of dirty LEB space. Returns
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* zero in case of success and a negative error code in case of failure.
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*/
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static inline int ubifs_add_dirt(struct ubifs_info *c, int lnum, int dirty)
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{
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return ubifs_update_one_lp(c, lnum, LPROPS_NC, dirty, 0, 0);
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}
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/**
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* ubifs_return_leb - return LEB to lprops.
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* @c: the UBIFS file-system description object
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* @lnum: LEB to return
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*
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* This helper function cleans the "taken" flag of a logical eraseblock in the
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* lprops. Returns zero in case of success and a negative error code in case of
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* failure.
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*/
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static inline int ubifs_return_leb(struct ubifs_info *c, int lnum)
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{
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return ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
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LPROPS_TAKEN, 0);
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}
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/**
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* ubifs_idx_node_sz - return index node size.
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* @c: the UBIFS file-system description object
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* @child_cnt: number of children of this index node
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*/
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static inline int ubifs_idx_node_sz(const struct ubifs_info *c, int child_cnt)
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{
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return UBIFS_IDX_NODE_SZ + (UBIFS_BRANCH_SZ + c->key_len) * child_cnt;
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}
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/**
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* ubifs_idx_branch - return pointer to an index branch.
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* @c: the UBIFS file-system description object
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* @idx: index node
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* @bnum: branch number
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*/
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static inline
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struct ubifs_branch *ubifs_idx_branch(const struct ubifs_info *c,
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const struct ubifs_idx_node *idx,
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int bnum)
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{
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return (struct ubifs_branch *)((void *)idx->branches +
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(UBIFS_BRANCH_SZ + c->key_len) * bnum);
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}
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/**
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* ubifs_idx_key - return pointer to an index key.
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* @c: the UBIFS file-system description object
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* @idx: index node
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*/
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static inline void *ubifs_idx_key(const struct ubifs_info *c,
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const struct ubifs_idx_node *idx)
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{
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return (void *)((struct ubifs_branch *)idx->branches)->key;
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}
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/**
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* ubifs_reported_space - calculate reported free space.
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* @c: the UBIFS file-system description object
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* @free: amount of free space
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*
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* This function calculates amount of free space which will be reported to
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* user-space. User-space application tend to expect that if the file-system
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* (e.g., via the 'statfs()' call) reports that it has N bytes available, they
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* are able to write a file of size N. UBIFS attaches node headers to each data
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* node and it has to write indexind nodes as well. This introduces additional
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* overhead, and UBIFS it has to report sligtly less free space to meet the
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* above expectetion.
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*
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* This function assumes free space is made up of uncompressed data nodes and
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* full index nodes (one per data node, doubled because we always allow enough
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* space to write the index twice).
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*
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* Note, the calculation is pessimistic, which means that most of the time
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* UBIFS reports less space than it actually has.
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*/
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static inline long long ubifs_reported_space(const struct ubifs_info *c,
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uint64_t free)
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{
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int divisor, factor;
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divisor = UBIFS_MAX_DATA_NODE_SZ + (c->max_idx_node_sz << 1);
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factor = UBIFS_MAX_DATA_NODE_SZ - UBIFS_DATA_NODE_SZ;
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do_div(free, divisor);
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return free * factor;
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}
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/**
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* ubifs_current_time - round current time to time granularity.
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* @inode: inode
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*/
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static inline struct timespec ubifs_current_time(struct inode *inode)
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{
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return (inode->i_sb->s_time_gran < NSEC_PER_SEC) ?
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current_fs_time(inode->i_sb) : CURRENT_TIME_SEC;
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}
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#endif /* __UBIFS_MISC_H__ */
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