logfile.c

linux 内核源代码

			err = -EINVAL;
			goto err_out;
		}
	}
	/*
	 * If the restart page is modified by chkdsk or there are no active
	 * logfile clients, the logfile is consistent.  Otherwise, need to
	 * check the log client records for consistency, too.
	 */
	err = 0;
	if (ntfs_is_rstr_record(rp->magic) &&
			ra->client_in_use_list != LOGFILE_NO_CLIENT) {
		if (!ntfs_check_log_client_array(vi, trp)) {
			err = -EINVAL;
			goto err_out;
		}
	}
	if (lsn) {
		if (ntfs_is_rstr_record(rp->magic))
			*lsn = sle64_to_cpu(ra->current_lsn);
		else /* if (ntfs_is_chkd_record(rp->magic)) */
			*lsn = sle64_to_cpu(rp->chkdsk_lsn);
	}
	ntfs_debug("Done.");
	if (wrp)
		*wrp = trp;
	else {
err_out:
		ntfs_free(trp);
	}
	return err;
}

/**
 * ntfs_check_logfile - check the journal for consistency
 * @log_vi:	struct inode of loaded journal $LogFile to check
 * @rp:		[OUT] on success this is a copy of the current restart page
 *
 * Check the $LogFile journal for consistency and return 'true' if it is
 * consistent and 'false' if not.  On success, the current restart page is
 * returned in *@rp.  Caller must call ntfs_free(*@rp) when finished with it.
 *
 * At present we only check the two restart pages and ignore the log record
 * pages.
 *
 * Note that the MstProtected flag is not set on the $LogFile inode and hence
 * when reading pages they are not deprotected.  This is because we do not know
 * if the $LogFile was created on a system with a different page size to ours
 * yet and mst deprotection would fail if our page size is smaller.
 */
bool ntfs_check_logfile(struct inode *log_vi, RESTART_PAGE_HEADER **rp)
{
	s64 size, pos;
	LSN rstr1_lsn, rstr2_lsn;
	ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
	struct address_space *mapping = log_vi->i_mapping;
	struct page *page = NULL;
	u8 *kaddr = NULL;
	RESTART_PAGE_HEADER *rstr1_ph = NULL;
	RESTART_PAGE_HEADER *rstr2_ph = NULL;
	int log_page_size, log_page_mask, err;
	bool logfile_is_empty = true;
	u8 log_page_bits;

	ntfs_debug("Entering.");
	/* An empty $LogFile must have been clean before it got emptied. */
	if (NVolLogFileEmpty(vol))
		goto is_empty;
	size = i_size_read(log_vi);
	/* Make sure the file doesn't exceed the maximum allowed size. */
	if (size > MaxLogFileSize)
		size = MaxLogFileSize;
	/*
	 * Truncate size to a multiple of the page cache size or the default
	 * log page size if the page cache size is between the default log page
	 * log page size if the page cache size is between the default log page
	 * size and twice that.
	 */
	if (PAGE_CACHE_SIZE >= DefaultLogPageSize && PAGE_CACHE_SIZE <=
			DefaultLogPageSize * 2)
		log_page_size = DefaultLogPageSize;
	else
		log_page_size = PAGE_CACHE_SIZE;
	log_page_mask = log_page_size - 1;
	/*
	 * Use ntfs_ffs() instead of ffs() to enable the compiler to
	 * optimize log_page_size and log_page_bits into constants.
	 */
	log_page_bits = ntfs_ffs(log_page_size) - 1;
	size &= ~(s64)(log_page_size - 1);
	/*
	 * Ensure the log file is big enough to store at least the two restart
	 * pages and the minimum number of log record pages.
	 */
	if (size < log_page_size * 2 || (size - log_page_size * 2) >>
			log_page_bits < MinLogRecordPages) {
		ntfs_error(vol->sb, "$LogFile is too small.");
		return false;
	}
	/*
	 * Read through the file looking for a restart page.  Since the restart
	 * page header is at the beginning of a page we only need to search at
	 * what could be the beginning of a page (for each page size) rather
	 * than scanning the whole file byte by byte.  If all potential places
	 * contain empty and uninitialzed records, the log file can be assumed
	 * to be empty.
	 */
	for (pos = 0; pos < size; pos <<= 1) {
		pgoff_t idx = pos >> PAGE_CACHE_SHIFT;
		if (!page || page->index != idx) {
			if (page)
				ntfs_unmap_page(page);
			page = ntfs_map_page(mapping, idx);
			if (IS_ERR(page)) {
				ntfs_error(vol->sb, "Error mapping $LogFile "
						"page (index %lu).", idx);
				goto err_out;
			}
		}
		kaddr = (u8*)page_address(page) + (pos & ~PAGE_CACHE_MASK);
		/*
		 * A non-empty block means the logfile is not empty while an
		 * empty block after a non-empty block has been encountered
		 * means we are done.
		 */
		if (!ntfs_is_empty_recordp((le32*)kaddr))
			logfile_is_empty = false;
		else if (!logfile_is_empty)
			break;
		/*
		 * A log record page means there cannot be a restart page after
		 * this so no need to continue searching.
		 */
		if (ntfs_is_rcrd_recordp((le32*)kaddr))
			break;
		/* If not a (modified by chkdsk) restart page, continue. */
		if (!ntfs_is_rstr_recordp((le32*)kaddr) &&
				!ntfs_is_chkd_recordp((le32*)kaddr)) {
			if (!pos)
				pos = NTFS_BLOCK_SIZE >> 1;
			continue;
		}
		/*
		 * Check the (modified by chkdsk) restart page for consistency
		 * and get a copy of the complete multi sector transfer
		 * deprotected restart page.
		 */
		err = ntfs_check_and_load_restart_page(log_vi,
				(RESTART_PAGE_HEADER*)kaddr, pos,
				!rstr1_ph ? &rstr1_ph : &rstr2_ph,
				!rstr1_ph ? &rstr1_lsn : &rstr2_lsn);
		if (!err) {
			/*
			 * If we have now found the first (modified by chkdsk)
			 * restart page, continue looking for the second one.
			 */
			if (!pos) {
				pos = NTFS_BLOCK_SIZE >> 1;
				continue;
			}
			/*
			 * We have now found the second (modified by chkdsk)
			 * restart page, so we can stop looking.
			 */
			break;
		}
		/*
		 * Error output already done inside the function.  Note, we do
		 * not abort if the restart page was invalid as we might still
		 * find a valid one further in the file.
		 */
		if (err != -EINVAL) {
			ntfs_unmap_page(page);
			goto err_out;
		}
		/* Continue looking. */
		if (!pos)
			pos = NTFS_BLOCK_SIZE >> 1;
	}
	if (page)
		ntfs_unmap_page(page);
	if (logfile_is_empty) {
		NVolSetLogFileEmpty(vol);
is_empty:
		ntfs_debug("Done.  ($LogFile is empty.)");
		return true;
	}
	if (!rstr1_ph) {
		BUG_ON(rstr2_ph);
		ntfs_error(vol->sb, "Did not find any restart pages in "
				"$LogFile and it was not empty.");
		return false;
	}
	/* If both restart pages were found, use the more recent one. */
	if (rstr2_ph) {
		/*
		 * If the second restart area is more recent, switch to it.
		 * Otherwise just throw it away.
		 */
		if (rstr2_lsn > rstr1_lsn) {
			ntfs_debug("Using second restart page as it is more "
					"recent.");
			ntfs_free(rstr1_ph);
			rstr1_ph = rstr2_ph;
			/* rstr1_lsn = rstr2_lsn; */
		} else {
			ntfs_debug("Using first restart page as it is more "
					"recent.");
			ntfs_free(rstr2_ph);
		}
		rstr2_ph = NULL;
	}
	/* All consistency checks passed. */
	if (rp)
		*rp = rstr1_ph;
	else
		ntfs_free(rstr1_ph);
	ntfs_debug("Done.");
	return true;
err_out:
	if (rstr1_ph)
		ntfs_free(rstr1_ph);
	return false;
}

/**
 * ntfs_is_logfile_clean - check in the journal if the volume is clean
 * @log_vi:	struct inode of loaded journal $LogFile to check
 * @rp:		copy of the current restart page
 *
 * Analyze the $LogFile journal and return 'true' if it indicates the volume was
 * shutdown cleanly and 'false' if not.
 *
 * At present we only look at the two restart pages and ignore the log record
 * pages.  This is a little bit crude in that there will be a very small number
 * of cases where we think that a volume is dirty when in fact it is clean.
 * This should only affect volumes that have not been shutdown cleanly but did
 * not have any pending, non-check-pointed i/o, i.e. they were completely idle
 * at least for the five seconds preceeding the unclean shutdown.
 *
 * This function assumes that the $LogFile journal has already been consistency
 * checked by a call to ntfs_check_logfile() and in particular if the $LogFile
 * is empty this function requires that NVolLogFileEmpty() is true otherwise an
 * empty volume will be reported as dirty.
 */
bool ntfs_is_logfile_clean(struct inode *log_vi, const RESTART_PAGE_HEADER *rp)
{
	ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
	RESTART_AREA *ra;

	ntfs_debug("Entering.");
	/* An empty $LogFile must have been clean before it got emptied. */
	if (NVolLogFileEmpty(vol)) {
		ntfs_debug("Done.  ($LogFile is empty.)");
		return true;
	}
	BUG_ON(!rp);
	if (!ntfs_is_rstr_record(rp->magic) &&
			!ntfs_is_chkd_record(rp->magic)) {
		ntfs_error(vol->sb, "Restart page buffer is invalid.  This is "
				"probably a bug in that the $LogFile should "
				"have been consistency checked before calling "
				"this function.");
		return false;
	}
	ra = (RESTART_AREA*)((u8*)rp + le16_to_cpu(rp->restart_area_offset));
	/*
	 * If the $LogFile has active clients, i.e. it is open, and we do not
	 * have the RESTART_VOLUME_IS_CLEAN bit set in the restart area flags,
	 * we assume there was an unclean shutdown.
	 */
	if (ra->client_in_use_list != LOGFILE_NO_CLIENT &&
			!(ra->flags & RESTART_VOLUME_IS_CLEAN)) {
		ntfs_debug("Done.  $LogFile indicates a dirty shutdown.");
		return false;
	}
	/* $LogFile indicates a clean shutdown. */
	ntfs_debug("Done.  $LogFile indicates a clean shutdown.");
	return true;
}

/**
 * ntfs_empty_logfile - empty the contents of the $LogFile journal
 * @log_vi:	struct inode of loaded journal $LogFile to empty
 *
 * Empty the contents of the $LogFile journal @log_vi and return 'true' on
 * success and 'false' on error.
 *
 * This function assumes that the $LogFile journal has already been consistency
 * checked by a call to ntfs_check_logfile() and that ntfs_is_logfile_clean()
 * has been used to ensure that the $LogFile is clean.
 */
bool ntfs_empty_logfile(struct inode *log_vi)
{
	VCN vcn, end_vcn;
	ntfs_inode *log_ni = NTFS_I(log_vi);
	ntfs_volume *vol = log_ni->vol;
	struct super_block *sb = vol->sb;
	runlist_element *rl;
	unsigned long flags;
	unsigned block_size, block_size_bits;
	int err;
	bool should_wait = true;

	ntfs_debug("Entering.");
	if (NVolLogFileEmpty(vol)) {
		ntfs_debug("Done.");
		return true;
	}
	/*
	 * We cannot use ntfs_attr_set() because we may be still in the middle
	 * of a mount operation.  Thus we do the emptying by hand by first
	 * zapping the page cache pages for the $LogFile/$DATA attribute and
	 * then emptying each of the buffers in each of the clusters specified
	 * by the runlist by hand.
	 */
	block_size = sb->s_blocksize;
	block_size_bits = sb->s_blocksize_bits;
	vcn = 0;
	read_lock_irqsave(&log_ni->size_lock, flags);
	end_vcn = (log_ni->initialized_size + vol->cluster_size_mask) >>
			vol->cluster_size_bits;
	read_unlock_irqrestore(&log_ni->size_lock, flags);
	truncate_inode_pages(log_vi->i_mapping, 0);
	down_write(&log_ni->runlist.lock);
	rl = log_ni->runlist.rl;
	if (unlikely(!rl || vcn < rl->vcn || !rl->length)) {
map_vcn:
		err = ntfs_map_runlist_nolock(log_ni, vcn, NULL);
		if (err) {
			ntfs_error(sb, "Failed to map runlist fragment (error "
					"%d).", -err);
			goto err;
		}
		rl = log_ni->runlist.rl;
		BUG_ON(!rl || vcn < rl->vcn || !rl->length);
	}
	/* Seek to the runlist element containing @vcn. */
	while (rl->length && vcn >= rl[1].vcn)
		rl++;
	do {
		LCN lcn;
		sector_t block, end_block;
		s64 len;

		/*
		 * If this run is not mapped map it now and start again as the
		 * runlist will have been updated.
		 */
		lcn = rl->lcn;
		if (unlikely(lcn == LCN_RL_NOT_MAPPED)) {
			vcn = rl->vcn;
			goto map_vcn;
		}
		/* If this run is not valid abort with an error. */
		if (unlikely(!rl->length || lcn < LCN_HOLE))
			goto rl_err;
		/* Skip holes. */
		if (lcn == LCN_HOLE)
			continue;
		block = lcn << vol->cluster_size_bits >> block_size_bits;
		len = rl->length;
		if (rl[1].vcn > end_vcn)
			len = end_vcn - rl->vcn;
		end_block = (lcn + len) << vol->cluster_size_bits >>
				block_size_bits;
		/* Iterate over the blocks in the run and empty them. */
		do {
			struct buffer_head *bh;

			/* Obtain the buffer, possibly not uptodate. */
			bh = sb_getblk(sb, block);
			BUG_ON(!bh);
			/* Setup buffer i/o submission. */
			lock_buffer(bh);
			bh->b_end_io = end_buffer_write_sync;
			get_bh(bh);
			/* Set the entire contents of the buffer to 0xff. */
			memset(bh->b_data, -1, block_size);
			if (!buffer_uptodate(bh))
				set_buffer_uptodate(bh);
			if (buffer_dirty(bh))
				clear_buffer_dirty(bh);
			/*
			 * Submit the buffer and wait for i/o to complete but
			 * only for the first buffer so we do not miss really
			 * serious i/o errors.  Once the first buffer has
			 * completed ignore errors afterwards as we can assume
			 * that if one buffer worked all of them will work.
			 */
			submit_bh(WRITE, bh);
			if (should_wait) {
				should_wait = false;
				wait_on_buffer(bh);
				if (unlikely(!buffer_uptodate(bh)))
					goto io_err;
			}
			brelse(bh);
		} while (++block < end_block);
	} while ((++rl)->vcn < end_vcn);
	up_write(&log_ni->runlist.lock);
	/*
	 * Zap the pages again just in case any got instantiated whilst we were
	 * emptying the blocks by hand.  FIXME: We may not have completed
	 * writing to all the buffer heads yet so this may happen too early.
	 * We really should use a kernel thread to do the emptying
	 * asynchronously and then we can also set the volume dirty and output
	 * an error message if emptying should fail.
	 */
	truncate_inode_pages(log_vi->i_mapping, 0);
	/* Set the flag so we do not have to do it again on remount. */
	NVolSetLogFileEmpty(vol);
	ntfs_debug("Done.");
	return true;
io_err:
	ntfs_error(sb, "Failed to write buffer.  Unmount and run chkdsk.");
	goto dirty_err;
rl_err:
	ntfs_error(sb, "Runlist is corrupt.  Unmount and run chkdsk.");
dirty_err:
	NVolSetErrors(vol);
	err = -EIO;
err:
	up_write(&log_ni->runlist.lock);
	ntfs_error(sb, "Failed to fill $LogFile with 0xff bytes (error %d).",
			-err);
	return false;
}

#endif /* NTFS_RW */