xfs_da_btree.c

linux 内核源代码

	}
	return off == bno + count;
}

/*
 * Make a dabuf.
 * Used for get_buf, read_buf, read_bufr, and reada_buf.
 */
STATIC int
xfs_da_do_buf(
	xfs_trans_t	*trans,
	xfs_inode_t	*dp,
	xfs_dablk_t	bno,
	xfs_daddr_t	*mappedbnop,
	xfs_dabuf_t	**bpp,
	int		whichfork,
	int		caller,
	inst_t		*ra)
{
	xfs_buf_t	*bp = NULL;
	xfs_buf_t	**bplist;
	int		error=0;
	int		i;
	xfs_bmbt_irec_t	map;
	xfs_bmbt_irec_t	*mapp;
	xfs_daddr_t	mappedbno;
	xfs_mount_t	*mp;
	int		nbplist=0;
	int		nfsb;
	int		nmap;
	xfs_dabuf_t	*rbp;

	mp = dp->i_mount;
	nfsb = (whichfork == XFS_DATA_FORK) ? mp->m_dirblkfsbs : 1;
	mappedbno = *mappedbnop;
	/*
	 * Caller doesn't have a mapping.  -2 means don't complain
	 * if we land in a hole.
	 */
	if (mappedbno == -1 || mappedbno == -2) {
		/*
		 * Optimize the one-block case.
		 */
		if (nfsb == 1) {
			xfs_fsblock_t	fsb;

			if ((error =
			    xfs_bmapi_single(trans, dp, whichfork, &fsb,
				    (xfs_fileoff_t)bno))) {
				return error;
			}
			mapp = ↦
			if (fsb == NULLFSBLOCK) {
				nmap = 0;
			} else {
				map.br_startblock = fsb;
				map.br_startoff = (xfs_fileoff_t)bno;
				map.br_blockcount = 1;
				nmap = 1;
			}
		} else {
			mapp = kmem_alloc(sizeof(*mapp) * nfsb, KM_SLEEP);
			nmap = nfsb;
			if ((error = xfs_bmapi(trans, dp, (xfs_fileoff_t)bno,
					nfsb,
					XFS_BMAPI_METADATA |
						XFS_BMAPI_AFLAG(whichfork),
					NULL, 0, mapp, &nmap, NULL, NULL)))
				goto exit0;
		}
	} else {
		map.br_startblock = XFS_DADDR_TO_FSB(mp, mappedbno);
		map.br_startoff = (xfs_fileoff_t)bno;
		map.br_blockcount = nfsb;
		mapp = ↦
		nmap = 1;
	}
	if (!xfs_da_map_covers_blocks(nmap, mapp, bno, nfsb)) {
		error = mappedbno == -2 ? 0 : XFS_ERROR(EFSCORRUPTED);
		if (unlikely(error == EFSCORRUPTED)) {
			if (xfs_error_level >= XFS_ERRLEVEL_LOW) {
				cmn_err(CE_ALERT, "xfs_da_do_buf: bno %lld\n",
					(long long)bno);
				cmn_err(CE_ALERT, "dir: inode %lld\n",
					(long long)dp->i_ino);
				for (i = 0; i < nmap; i++) {
					cmn_err(CE_ALERT,
						"[%02d] br_startoff %lld br_startblock %lld br_blockcount %lld br_state %d\n",
						i,
						(long long)mapp[i].br_startoff,
						(long long)mapp[i].br_startblock,
						(long long)mapp[i].br_blockcount,
						mapp[i].br_state);
				}
			}
			XFS_ERROR_REPORT("xfs_da_do_buf(1)",
					 XFS_ERRLEVEL_LOW, mp);
		}
		goto exit0;
	}
	if (caller != 3 && nmap > 1) {
		bplist = kmem_alloc(sizeof(*bplist) * nmap, KM_SLEEP);
		nbplist = 0;
	} else
		bplist = NULL;
	/*
	 * Turn the mapping(s) into buffer(s).
	 */
	for (i = 0; i < nmap; i++) {
		int	nmapped;

		mappedbno = XFS_FSB_TO_DADDR(mp, mapp[i].br_startblock);
		if (i == 0)
			*mappedbnop = mappedbno;
		nmapped = (int)XFS_FSB_TO_BB(mp, mapp[i].br_blockcount);
		switch (caller) {
		case 0:
			bp = xfs_trans_get_buf(trans, mp->m_ddev_targp,
				mappedbno, nmapped, 0);
			error = bp ? XFS_BUF_GETERROR(bp) : XFS_ERROR(EIO);
			break;
		case 1:
		case 2:
			bp = NULL;
			error = xfs_trans_read_buf(mp, trans, mp->m_ddev_targp,
				mappedbno, nmapped, 0, &bp);
			break;
		case 3:
			xfs_baread(mp->m_ddev_targp, mappedbno, nmapped);
			error = 0;
			bp = NULL;
			break;
		}
		if (error) {
			if (bp)
				xfs_trans_brelse(trans, bp);
			goto exit1;
		}
		if (!bp)
			continue;
		if (caller == 1) {
			if (whichfork == XFS_ATTR_FORK) {
				XFS_BUF_SET_VTYPE_REF(bp, B_FS_ATTR_BTREE,
						XFS_ATTR_BTREE_REF);
			} else {
				XFS_BUF_SET_VTYPE_REF(bp, B_FS_DIR_BTREE,
						XFS_DIR_BTREE_REF);
			}
		}
		if (bplist) {
			bplist[nbplist++] = bp;
		}
	}
	/*
	 * Build a dabuf structure.
	 */
	if (bplist) {
		rbp = xfs_da_buf_make(nbplist, bplist, ra);
	} else if (bp)
		rbp = xfs_da_buf_make(1, &bp, ra);
	else
		rbp = NULL;
	/*
	 * For read_buf, check the magic number.
	 */
	if (caller == 1) {
		xfs_dir2_data_t		*data;
		xfs_dir2_free_t		*free;
		xfs_da_blkinfo_t	*info;
		uint			magic, magic1;

		info = rbp->data;
		data = rbp->data;
		free = rbp->data;
		magic = be16_to_cpu(info->magic);
		magic1 = be32_to_cpu(data->hdr.magic);
		if (unlikely(
		    XFS_TEST_ERROR((magic != XFS_DA_NODE_MAGIC) &&
				   (magic != XFS_ATTR_LEAF_MAGIC) &&
				   (magic != XFS_DIR2_LEAF1_MAGIC) &&
				   (magic != XFS_DIR2_LEAFN_MAGIC) &&
				   (magic1 != XFS_DIR2_BLOCK_MAGIC) &&
				   (magic1 != XFS_DIR2_DATA_MAGIC) &&
				   (be32_to_cpu(free->hdr.magic) != XFS_DIR2_FREE_MAGIC),
				mp, XFS_ERRTAG_DA_READ_BUF,
				XFS_RANDOM_DA_READ_BUF))) {
			xfs_buftrace("DA READ ERROR", rbp->bps[0]);
			XFS_CORRUPTION_ERROR("xfs_da_do_buf(2)",
					     XFS_ERRLEVEL_LOW, mp, info);
			error = XFS_ERROR(EFSCORRUPTED);
			xfs_da_brelse(trans, rbp);
			nbplist = 0;
			goto exit1;
		}
	}
	if (bplist) {
		kmem_free(bplist, sizeof(*bplist) * nmap);
	}
	if (mapp != &map) {
		kmem_free(mapp, sizeof(*mapp) * nfsb);
	}
	if (bpp)
		*bpp = rbp;
	return 0;
exit1:
	if (bplist) {
		for (i = 0; i < nbplist; i++)
			xfs_trans_brelse(trans, bplist[i]);
		kmem_free(bplist, sizeof(*bplist) * nmap);
	}
exit0:
	if (mapp != &map)
		kmem_free(mapp, sizeof(*mapp) * nfsb);
	if (bpp)
		*bpp = NULL;
	return error;
}

/*
 * Get a buffer for the dir/attr block.
 */
int
xfs_da_get_buf(
	xfs_trans_t	*trans,
	xfs_inode_t	*dp,
	xfs_dablk_t	bno,
	xfs_daddr_t		mappedbno,
	xfs_dabuf_t	**bpp,
	int		whichfork)
{
	return xfs_da_do_buf(trans, dp, bno, &mappedbno, bpp, whichfork, 0,
						 (inst_t *)__return_address);
}

/*
 * Get a buffer for the dir/attr block, fill in the contents.
 */
int
xfs_da_read_buf(
	xfs_trans_t	*trans,
	xfs_inode_t	*dp,
	xfs_dablk_t	bno,
	xfs_daddr_t		mappedbno,
	xfs_dabuf_t	**bpp,
	int		whichfork)
{
	return xfs_da_do_buf(trans, dp, bno, &mappedbno, bpp, whichfork, 1,
		(inst_t *)__return_address);
}

/*
 * Readahead the dir/attr block.
 */
xfs_daddr_t
xfs_da_reada_buf(
	xfs_trans_t	*trans,
	xfs_inode_t	*dp,
	xfs_dablk_t	bno,
	int		whichfork)
{
	xfs_daddr_t		rval;

	rval = -1;
	if (xfs_da_do_buf(trans, dp, bno, &rval, NULL, whichfork, 3,
			(inst_t *)__return_address))
		return -1;
	else
		return rval;
}

kmem_zone_t *xfs_da_state_zone;	/* anchor for state struct zone */
kmem_zone_t *xfs_dabuf_zone;		/* dabuf zone */

/*
 * Allocate a dir-state structure.
 * We don't put them on the stack since they're large.
 */
xfs_da_state_t *
xfs_da_state_alloc(void)
{
	return kmem_zone_zalloc(xfs_da_state_zone, KM_SLEEP);
}

/*
 * Kill the altpath contents of a da-state structure.
 */
STATIC void
xfs_da_state_kill_altpath(xfs_da_state_t *state)
{
	int	i;

	for (i = 0; i < state->altpath.active; i++) {
		if (state->altpath.blk[i].bp) {
			if (state->altpath.blk[i].bp != state->path.blk[i].bp)
				xfs_da_buf_done(state->altpath.blk[i].bp);
			state->altpath.blk[i].bp = NULL;
		}
	}
	state->altpath.active = 0;
}

/*
 * Free a da-state structure.
 */
void
xfs_da_state_free(xfs_da_state_t *state)
{
	int	i;

	xfs_da_state_kill_altpath(state);
	for (i = 0; i < state->path.active; i++) {
		if (state->path.blk[i].bp)
			xfs_da_buf_done(state->path.blk[i].bp);
	}
	if (state->extravalid && state->extrablk.bp)
		xfs_da_buf_done(state->extrablk.bp);
#ifdef DEBUG
	memset((char *)state, 0, sizeof(*state));
#endif /* DEBUG */
	kmem_zone_free(xfs_da_state_zone, state);
}

#ifdef XFS_DABUF_DEBUG
xfs_dabuf_t	*xfs_dabuf_global_list;
lock_t		xfs_dabuf_global_lock;
#endif

/*
 * Create a dabuf.
 */
/* ARGSUSED */
STATIC xfs_dabuf_t *
xfs_da_buf_make(int nbuf, xfs_buf_t **bps, inst_t *ra)
{
	xfs_buf_t	*bp;
	xfs_dabuf_t	*dabuf;
	int		i;
	int		off;

	if (nbuf == 1)
		dabuf = kmem_zone_alloc(xfs_dabuf_zone, KM_SLEEP);
	else
		dabuf = kmem_alloc(XFS_DA_BUF_SIZE(nbuf), KM_SLEEP);
	dabuf->dirty = 0;
#ifdef XFS_DABUF_DEBUG
	dabuf->ra = ra;
	dabuf->target = XFS_BUF_TARGET(bps[0]);
	dabuf->blkno = XFS_BUF_ADDR(bps[0]);
#endif
	if (nbuf == 1) {
		dabuf->nbuf = 1;
		bp = bps[0];
		dabuf->bbcount = (short)BTOBB(XFS_BUF_COUNT(bp));
		dabuf->data = XFS_BUF_PTR(bp);
		dabuf->bps[0] = bp;
	} else {
		dabuf->nbuf = nbuf;
		for (i = 0, dabuf->bbcount = 0; i < nbuf; i++) {
			dabuf->bps[i] = bp = bps[i];
			dabuf->bbcount += BTOBB(XFS_BUF_COUNT(bp));
		}
		dabuf->data = kmem_alloc(BBTOB(dabuf->bbcount), KM_SLEEP);
		for (i = off = 0; i < nbuf; i++, off += XFS_BUF_COUNT(bp)) {
			bp = bps[i];
			memcpy((char *)dabuf->data + off, XFS_BUF_PTR(bp),
				XFS_BUF_COUNT(bp));
		}
	}
#ifdef XFS_DABUF_DEBUG
	{
		SPLDECL(s);
		xfs_dabuf_t	*p;

		s = mutex_spinlock(&xfs_dabuf_global_lock);
		for (p = xfs_dabuf_global_list; p; p = p->next) {
			ASSERT(p->blkno != dabuf->blkno ||
			       p->target != dabuf->target);
		}
		dabuf->prev = NULL;
		if (xfs_dabuf_global_list)
			xfs_dabuf_global_list->prev = dabuf;
		dabuf->next = xfs_dabuf_global_list;
		xfs_dabuf_global_list = dabuf;
		mutex_spinunlock(&xfs_dabuf_global_lock, s);
	}
#endif
	return dabuf;
}

/*
 * Un-dirty a dabuf.
 */
STATIC void
xfs_da_buf_clean(xfs_dabuf_t *dabuf)
{
	xfs_buf_t	*bp;
	int		i;
	int		off;

	if (dabuf->dirty) {
		ASSERT(dabuf->nbuf > 1);
		dabuf->dirty = 0;
		for (i = off = 0; i < dabuf->nbuf;
				i++, off += XFS_BUF_COUNT(bp)) {
			bp = dabuf->bps[i];
			memcpy(XFS_BUF_PTR(bp), (char *)dabuf->data + off,
				XFS_BUF_COUNT(bp));
		}
	}
}

/*
 * Release a dabuf.
 */
void
xfs_da_buf_done(xfs_dabuf_t *dabuf)
{
	ASSERT(dabuf);
	ASSERT(dabuf->nbuf && dabuf->data && dabuf->bbcount && dabuf->bps[0]);
	if (dabuf->dirty)
		xfs_da_buf_clean(dabuf);
	if (dabuf->nbuf > 1)
		kmem_free(dabuf->data, BBTOB(dabuf->bbcount));
#ifdef XFS_DABUF_DEBUG
	{
		SPLDECL(s);

		s = mutex_spinlock(&xfs_dabuf_global_lock);
		if (dabuf->prev)
			dabuf->prev->next = dabuf->next;
		else
			xfs_dabuf_global_list = dabuf->next;
		if (dabuf->next)
			dabuf->next->prev = dabuf->prev;
		mutex_spinunlock(&xfs_dabuf_global_lock, s);
	}
	memset(dabuf, 0, XFS_DA_BUF_SIZE(dabuf->nbuf));
#endif
	if (dabuf->nbuf == 1)
		kmem_zone_free(xfs_dabuf_zone, dabuf);
	else
		kmem_free(dabuf, XFS_DA_BUF_SIZE(dabuf->nbuf));
}

/*
 * Log transaction from a dabuf.
 */
void
xfs_da_log_buf(xfs_trans_t *tp, xfs_dabuf_t *dabuf, uint first, uint last)
{
	xfs_buf_t	*bp;
	uint		f;
	int		i;
	uint		l;
	int		off;

	ASSERT(dabuf->nbuf && dabuf->data && dabuf->bbcount && dabuf->bps[0]);
	if (dabuf->nbuf == 1) {
		ASSERT(dabuf->data == (void *)XFS_BUF_PTR(dabuf->bps[0]));
		xfs_trans_log_buf(tp, dabuf->bps[0], first, last);
		return;
	}
	dabuf->dirty = 1;
	ASSERT(first <= last);
	for (i = off = 0; i < dabuf->nbuf; i++, off += XFS_BUF_COUNT(bp)) {
		bp = dabuf->bps[i];
		f = off;
		l = f + XFS_BUF_COUNT(bp) - 1;
		if (f < first)
			f =