C++ BBTOB函数代码示例

/*
 * Mark bytes first through last inclusive as dirty in the buf
 * item's bitmap.
 */
void
xfs_buf_item_log(
	xfs_buf_log_item_t	*bip,
	uint			first,
	uint			last)
{
	int			i;
	uint			start;
	uint			end;
	struct xfs_buf		*bp = bip->bli_buf;

	/*
	 * walk each buffer segment and mark them dirty appropriately.
	 */
	start = 0;
	for (i = 0; i < bip->bli_format_count; i++) {
		if (start > last)
			break;
		end = start + BBTOB(bp->b_maps[i].bm_len);
		if (first > end) {
			start += BBTOB(bp->b_maps[i].bm_len);
			continue;
		}
		if (first < start)
			first = start;
		if (end > last)
			end = last;

		xfs_buf_item_log_segment(first, end,
					 &bip->bli_formats[i].blf_data_map[0]);

		start += bp->b_maps[i].bm_len;
	}
}

/*
 * initialize a buffer full of dquots and log the whole thing
 */
STATIC void
xfs_qm_init_dquot_blk(
	xfs_trans_t	*tp,
	xfs_mount_t	*mp,
	xfs_dqid_t	id,
	uint		type,
	xfs_buf_t	*bp)
{
	xfs_dqblk_t	*d;
	int		curid, i;

	ASSERT(tp);
	ASSERT(XFS_BUF_ISBUSY(bp));
	ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);

	d = (xfs_dqblk_t *)XFS_BUF_PTR(bp);

	/*
	 * ID of the first dquot in the block - id's are zero based.
	 */
	curid = id - (id % XFS_QM_DQPERBLK(mp));
	ASSERT(curid >= 0);
	memset(d, 0, BBTOB(XFS_QI_DQCHUNKLEN(mp)));
	for (i = 0; i < XFS_QM_DQPERBLK(mp); i++, d++, curid++)
		xfs_qm_dqinit_core(curid, type, d);
	xfs_trans_dquot_buf(tp, bp,
			    (type & XFS_DQ_USER ? XFS_BLI_UDQUOT_BUF :
			    ((type & XFS_DQ_PROJ) ? XFS_BLI_PDQUOT_BUF :
			     XFS_BLI_GDQUOT_BUF)));
	xfs_trans_log_buf(tp, bp, 0, BBTOB(XFS_QI_DQCHUNKLEN(mp)) - 1);
}

/* Convert an xfs_fsmap to an fsmap. */
void
xfs_fsmap_from_internal(
	struct fsmap		*dest,
	struct xfs_fsmap	*src)
{
	dest->fmr_device = src->fmr_device;
	dest->fmr_flags = src->fmr_flags;
	dest->fmr_physical = BBTOB(src->fmr_physical);
	dest->fmr_owner = src->fmr_owner;
	dest->fmr_offset = BBTOB(src->fmr_offset);
	dest->fmr_length = BBTOB(src->fmr_length);
	dest->fmr_reserved[0] = 0;
	dest->fmr_reserved[1] = 0;
	dest->fmr_reserved[2] = 0;
}

void
xfs_symlink_local_to_remote(
	struct xfs_trans	*tp,
	struct xfs_buf		*bp,
	struct xfs_inode	*ip,
	struct xfs_ifork	*ifp)
{
	struct xfs_mount	*mp = ip->i_mount;
	char			*buf;

	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);

	if (!xfs_sb_version_hascrc(&mp->m_sb)) {
		bp->b_ops = NULL;
		memcpy(bp->b_addr, ifp->if_u1.if_data, ifp->if_bytes);
		xfs_trans_log_buf(tp, bp, 0, ifp->if_bytes - 1);
		return;
	}

	/*
	 * As this symlink fits in an inode literal area, it must also fit in
	 * the smallest buffer the filesystem supports.
	 */
	ASSERT(BBTOB(bp->b_length) >=
			ifp->if_bytes + sizeof(struct xfs_dsymlink_hdr));

	bp->b_ops = &xfs_symlink_buf_ops;

	buf = bp->b_addr;
	buf += xfs_symlink_hdr_set(mp, ip->i_ino, 0, ifp->if_bytes, bp);
	memcpy(buf, ifp->if_u1.if_data, ifp->if_bytes);
	xfs_trans_log_buf(tp, bp, 0, sizeof(struct xfs_dsymlink_hdr) +
					ifp->if_bytes - 1);
}

/*
 * This function is called to verify that our callers have logged
 * all the bytes that they changed.
 *
 * It does this by comparing the original copy of the buffer stored in
 * the buf log item's bli_orig array to the current copy of the buffer
 * and ensuring that all bytes which mismatch are set in the bli_logged
 * array of the buf log item.
 */
STATIC void
xfs_buf_item_log_check(
	xfs_buf_log_item_t	*bip)
{
	char		*orig;
	char		*buffer;
	int		x;
	xfs_buf_t	*bp;

	ASSERT(bip->bli_orig != NULL);
	ASSERT(bip->bli_logged != NULL);

	bp = bip->bli_buf;
	ASSERT(bp->b_length > 0);
	ASSERT(bp->b_addr != NULL);
	orig = bip->bli_orig;
	buffer = bp->b_addr;
	for (x = 0; x < BBTOB(bp->b_length); x++) {
		if (orig[x] != buffer[x] && !btst(bip->bli_logged, x)) {
			xfs_emerg(bp->b_mount,
				"%s: bip %x buffer %x orig %x index %d",
				__func__, bip, bp, orig, x);
			ASSERT(0);
		}
	}
}

/* Initialize a new AG btree root block with zero entries. */
int
xrep_init_btblock(
	struct xfs_scrub		*sc,
	xfs_fsblock_t			fsb,
	struct xfs_buf			**bpp,
	xfs_btnum_t			btnum,
	const struct xfs_buf_ops	*ops)
{
	struct xfs_trans		*tp = sc->tp;
	struct xfs_mount		*mp = sc->mp;
	struct xfs_buf			*bp;

	trace_xrep_init_btblock(mp, XFS_FSB_TO_AGNO(mp, fsb),
			XFS_FSB_TO_AGBNO(mp, fsb), btnum);

	ASSERT(XFS_FSB_TO_AGNO(mp, fsb) == sc->sa.agno);
	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, XFS_FSB_TO_DADDR(mp, fsb),
			XFS_FSB_TO_BB(mp, 1), 0);
	xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
	xfs_btree_init_block(mp, bp, btnum, 0, 0, sc->sa.agno, 0);
	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_BTREE_BUF);
	xfs_trans_log_buf(tp, bp, 0, bp->b_length);
	bp->b_ops = ops;
	*bpp = bp;

	return 0;
}

/*
 * Warnings specifically for verifier errors.  Differentiate CRC vs. invalid
 * values, and omit the stack trace unless the error level is tuned high.
 */
void
xfs_verifier_error(
	struct xfs_buf		*bp)
{
	xfs_alert(NULL, "Metadata %s detected at %s block 0x%llx/0x%x",
		  bp->b_error == -EFSBADCRC ? "CRC error" : "corruption",
		  bp->b_ops->name, bp->b_bn, BBTOB(bp->b_length));
}

/*
 * Allocate a new buf log item to go with the given buffer.
 * Set the buffer's b_fsprivate field to point to the new
 * buf log item.  If there are other item's attached to the
 * buffer (see xfs_buf_attach_iodone() below), then put the
 * buf log item at the front.
 */
void
xfs_buf_item_init(
	xfs_buf_t	*bp,
	xfs_mount_t	*mp)
{
	xfs_log_item_t		*lip = bp->b_fspriv;
	xfs_buf_log_item_t	*bip;
	int			chunks;
	int			map_size;
	int			error;
	int			i;

	/*
	 * Check to see if there is already a buf log item for
	 * this buffer.  If there is, it is guaranteed to be
	 * the first.  If we do already have one, there is
	 * nothing to do here so return.
	 */
	ASSERT(bp->b_target->bt_mount == mp);
	if (lip != NULL && lip->li_type == XFS_LI_BUF)
		return;

	bip = kmem_zone_zalloc(xfs_buf_item_zone, KM_SLEEP);
	xfs_log_item_init(mp, &bip->bli_item, XFS_LI_BUF, &xfs_buf_item_ops);
	bip->bli_buf = bp;
	xfs_buf_hold(bp);

	/*
	 * chunks is the number of XFS_BLF_CHUNK size pieces the buffer
	 * can be divided into. Make sure not to truncate any pieces.
	 * map_size is the size of the bitmap needed to describe the
	 * chunks of the buffer.
	 *
	 * Discontiguous buffer support follows the layout of the underlying
	 * buffer. This makes the implementation as simple as possible.
	 */
	error = xfs_buf_item_get_format(bip, bp->b_map_count);
	ASSERT(error == 0);

	for (i = 0; i < bip->bli_format_count; i++) {
		chunks = DIV_ROUND_UP(BBTOB(bp->b_maps[i].bm_len),
				      XFS_BLF_CHUNK);
		map_size = DIV_ROUND_UP(chunks, NBWORD);

		bip->bli_formats[i].blf_type = XFS_LI_BUF;
		bip->bli_formats[i].blf_blkno = bp->b_maps[i].bm_bn;
		bip->bli_formats[i].blf_len = bp->b_maps[i].bm_len;
		bip->bli_formats[i].blf_map_size = map_size;
	}

	/*
	 * Put the buf item into the list of items attached to the
	 * buffer at the front.
	 */
	if (bp->b_fspriv)
		bip->bli_item.li_bio_list = bp->b_fspriv;
	bp->b_fspriv = bip;
}

xfs_buf_t *
xfs_buf_get_flags(xfs_buftarg_t *target, xfs_daddr_t blkno, size_t len, int flags)
{
	struct buf *bp = NULL;
	KASSERT((target != NULL), ("got NULL buftarg_t"));
	bp = getblk(target->specvp, blkno, BBTOB(len), 0, 0, 0);
	if (bp != NULL)
		xfs_buf_set_target(bp, target);
	return (bp);
}

/*
 * initialize a buffer full of dquots and log the whole thing
 */
STATIC void
xfs_qm_init_dquot_blk(
	xfs_trans_t	*tp,
	xfs_mount_t	*mp,
	xfs_dqid_t	id,
	uint		type,
	xfs_buf_t	*bp)
{
	struct xfs_quotainfo	*q = mp->m_quotainfo;
	xfs_dqblk_t	*d;
	int		curid, i;

	ASSERT(tp);
	ASSERT(xfs_buf_islocked(bp));

	d = bp->b_addr;

	/*
	 * ID of the first dquot in the block - id's are zero based.
	 */
	curid = id - (id % q->qi_dqperchunk);
	ASSERT(curid >= 0);
	memset(d, 0, BBTOB(q->qi_dqchunklen));
	for (i = 0; i < q->qi_dqperchunk; i++, d++, curid++) {
		d->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);
		d->dd_diskdq.d_version = XFS_DQUOT_VERSION;
		d->dd_diskdq.d_id = cpu_to_be32(curid);
		d->dd_diskdq.d_flags = type;
		if (xfs_sb_version_hascrc(&mp->m_sb)) {
			uuid_copy(&d->dd_uuid, &mp->m_sb.sb_uuid);
			xfs_update_cksum((char *)d, sizeof(struct xfs_dqblk),
					 XFS_DQUOT_CRC_OFF);
		}
	}

	xfs_trans_dquot_buf(tp, bp,
			    (type & XFS_DQ_USER ? XFS_BLF_UDQUOT_BUF :
			    ((type & XFS_DQ_PROJ) ? XFS_BLF_PDQUOT_BUF :
			     XFS_BLF_GDQUOT_BUF)));
	xfs_trans_log_buf(tp, bp, 0, BBTOB(q->qi_dqchunklen) - 1);
}

xfs_buf_t *
xfs_buf_read_flags(xfs_buftarg_t *target, xfs_daddr_t blkno, size_t len, int flags)
{
	struct buf *bp;
	KASSERT((target != NULL), ("got NULL buftarg_t"));

	if (bread(target->specvp, blkno, BBTOB(len), NOCRED, &bp)) {
		printf("bread failed specvp %p blkno %qd BBTOB(len) %ld\n",
		       target->specvp, blkno, (long)BBTOB(len));
		bp = NULL;
	}

	/* not really sure what B_MANAGED really does for us
	 * maybe we should drop this and just stick with a locked buf
	 */

	if (flags & B_MANAGED)
		bp->b_flags |= B_MANAGED;
	xfs_buf_set_target(bp, target);
	return (bp);
}

int
xfs_calc_dquots_per_chunk(
	struct xfs_mount	*mp,
	unsigned int		nbblks)	/* basic block units */
{
	unsigned int	ndquots;

	ASSERT(nbblks > 0);
	ndquots = BBTOB(nbblks);
	do_div(ndquots, sizeof(xfs_dqblk_t));

	return ndquots;
}

/*
 * Call fiemap helper to fill in user data.
 * Returns positive errors to xfs_getbmap.
 */
STATIC int
xfs_fiemap_format(
	void			**arg,
	struct getbmapx		*bmv,
	int			*full)
{
	int			error;
	struct fiemap_extent_info *fieinfo = *arg;
	u32			fiemap_flags = 0;
	u64			logical, physical, length;

	/* Do nothing for a hole */
	if (bmv->bmv_block == -1LL)
		return 0;

	logical = BBTOB(bmv->bmv_offset);
	physical = BBTOB(bmv->bmv_block);
	length = BBTOB(bmv->bmv_length);

	if (bmv->bmv_oflags & BMV_OF_PREALLOC)
		fiemap_flags |= FIEMAP_EXTENT_UNWRITTEN;
	else if (bmv->bmv_oflags & BMV_OF_DELALLOC) {
		fiemap_flags |= (FIEMAP_EXTENT_DELALLOC |
				 FIEMAP_EXTENT_UNKNOWN);
		physical = 0;   /* no block yet */
	}
	if (bmv->bmv_oflags & BMV_OF_LAST)
		fiemap_flags |= FIEMAP_EXTENT_LAST;

	error = fiemap_fill_next_extent(fieinfo, logical, physical,
					length, fiemap_flags);
	if (error > 0) {
		error = 0;
		*full = 1;	/* user array now full */
	}

	return -error;
}

void
xfs_buf_readahead(
		  xfs_buftarg_t		*target,
		  xfs_daddr_t		ioff,
		  size_t		isize,
		  xfs_buf_flags_t	flags)
{
	daddr_t rablkno;
	int rabsize;

	rablkno = ioff;
	rabsize = BBTOB(isize);
	breada(target->specvp, &rablkno, &rabsize, 1, NOCRED);
}

static void
xfs_dir3_block_read_verify(
	struct xfs_buf	*bp)
{
	struct xfs_mount	*mp = bp->b_target->bt_mount;

	if ((xfs_sb_version_hascrc(&mp->m_sb) &&
	     !xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
					  XFS_DIR3_DATA_CRC_OFF)) ||
	    !xfs_dir3_block_verify(bp)) {
		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
		xfs_buf_ioerror(bp, EFSCORRUPTED);
	}
}