C++ (Cpp) xfs_buf_get_uncached Examples

Example #1

File: xfs_ag.c Project: AlexShiLucky/linux

static struct xfs_buf *
xfs_get_aghdr_buf(
	struct xfs_mount	*mp,
	xfs_daddr_t		blkno,
	size_t			numblks,
	int			flags,
	const struct xfs_buf_ops *ops)
{
	struct xfs_buf		*bp;

	bp = xfs_buf_get_uncached(mp->m_ddev_targp, numblks, flags);
	if (!bp)
		return NULL;

	xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
	bp->b_bn = blkno;
	bp->b_maps[0].bm_bn = blkno;
	bp->b_ops = ops;

	return bp;
}

Example #2

File: xfs_bmap_util.c Project: Astralix/mainline-dss11

/*
 * Zero file bytes between startoff and endoff inclusive.
 * The iolock is held exclusive and no blocks are buffered.
 *
 * This function is used by xfs_free_file_space() to zero
 * partial blocks when the range to free is not block aligned.
 * When unreserving space with boundaries that are not block
 * aligned we round up the start and round down the end
 * boundaries and then use this function to zero the parts of
 * the blocks that got dropped during the rounding.
 */
STATIC int
xfs_zero_remaining_bytes(
	xfs_inode_t		*ip,
	xfs_off_t		startoff,
	xfs_off_t		endoff)
{
	xfs_bmbt_irec_t		imap;
	xfs_fileoff_t		offset_fsb;
	xfs_off_t		lastoffset;
	xfs_off_t		offset;
	xfs_buf_t		*bp;
	xfs_mount_t		*mp = ip->i_mount;
	int			nimap;
	int			error = 0;

	/*
	 * Avoid doing I/O beyond eof - it's not necessary
	 * since nothing can read beyond eof.  The space will
	 * be zeroed when the file is extended anyway.
	 */
	if (startoff >= XFS_ISIZE(ip))
		return 0;

	if (endoff > XFS_ISIZE(ip))
		endoff = XFS_ISIZE(ip);

	bp = xfs_buf_get_uncached(XFS_IS_REALTIME_INODE(ip) ?
					mp->m_rtdev_targp : mp->m_ddev_targp,
				  BTOBB(mp->m_sb.sb_blocksize), 0);
	if (!bp)
		return XFS_ERROR(ENOMEM);

	xfs_buf_unlock(bp);

	for (offset = startoff; offset <= endoff; offset = lastoffset + 1) {
		uint lock_mode;

		offset_fsb = XFS_B_TO_FSBT(mp, offset);
		nimap = 1;

		lock_mode = xfs_ilock_data_map_shared(ip);
		error = xfs_bmapi_read(ip, offset_fsb, 1, &imap, &nimap, 0);
		xfs_iunlock(ip, lock_mode);

		if (error || nimap < 1)
			break;
		ASSERT(imap.br_blockcount >= 1);
		ASSERT(imap.br_startoff == offset_fsb);
		lastoffset = XFS_FSB_TO_B(mp, imap.br_startoff + 1) - 1;
		if (lastoffset > endoff)
			lastoffset = endoff;
		if (imap.br_startblock == HOLESTARTBLOCK)
			continue;
		ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
		if (imap.br_state == XFS_EXT_UNWRITTEN)
			continue;
		XFS_BUF_UNDONE(bp);
		XFS_BUF_UNWRITE(bp);
		XFS_BUF_READ(bp);
		XFS_BUF_SET_ADDR(bp, xfs_fsb_to_db(ip, imap.br_startblock));

		if (XFS_FORCED_SHUTDOWN(mp)) {
			error = XFS_ERROR(EIO);
			break;
		}
		xfs_buf_iorequest(bp);
		error = xfs_buf_iowait(bp);
		if (error) {
			xfs_buf_ioerror_alert(bp,
					"xfs_zero_remaining_bytes(read)");
			break;
		}
		memset(bp->b_addr +
			(offset - XFS_FSB_TO_B(mp, imap.br_startoff)),
		      0, lastoffset - offset + 1);
		XFS_BUF_UNDONE(bp);
		XFS_BUF_UNREAD(bp);
		XFS_BUF_WRITE(bp);

		if (XFS_FORCED_SHUTDOWN(mp)) {
			error = XFS_ERROR(EIO);
			break;
		}
		xfs_buf_iorequest(bp);
		error = xfs_buf_iowait(bp);
		if (error) {
			xfs_buf_ioerror_alert(bp,
					"xfs_zero_remaining_bytes(write)");
			break;
		}
	}
	xfs_buf_free(bp);
	return error;
}