xfs_bmap.c

linux 内核源代码

 */
STATIC int					/* error */
xfs_bmap_add_attrfork_btree(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode pointer */
	xfs_fsblock_t		*firstblock,	/* first block allocated */
	xfs_bmap_free_t		*flist,		/* blocks to free at commit */
	int			*flags)		/* inode logging flags */
{
	xfs_btree_cur_t		*cur;		/* btree cursor */
	int			error;		/* error return value */
	xfs_mount_t		*mp;		/* file system mount struct */
	int			stat;		/* newroot status */

	mp = ip->i_mount;
	if (ip->i_df.if_broot_bytes <= XFS_IFORK_DSIZE(ip))
		*flags |= XFS_ILOG_DBROOT;
	else {
		cur = xfs_btree_init_cursor(mp, tp, NULL, 0, XFS_BTNUM_BMAP, ip,
			XFS_DATA_FORK);
		cur->bc_private.b.flist = flist;
		cur->bc_private.b.firstblock = *firstblock;
		if ((error = xfs_bmbt_lookup_ge(cur, 0, 0, 0, &stat)))
			goto error0;
		ASSERT(stat == 1);	/* must be at least one entry */
		if ((error = xfs_bmbt_newroot(cur, flags, &stat)))
			goto error0;
		if (stat == 0) {
			xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
			return XFS_ERROR(ENOSPC);
		}
		*firstblock = cur->bc_private.b.firstblock;
		cur->bc_private.b.allocated = 0;
		xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
	}
	return 0;
error0:
	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
	return error;
}

/*
 * Called from xfs_bmap_add_attrfork to handle extents format files.
 */
STATIC int					/* error */
xfs_bmap_add_attrfork_extents(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode pointer */
	xfs_fsblock_t		*firstblock,	/* first block allocated */
	xfs_bmap_free_t		*flist,		/* blocks to free at commit */
	int			*flags)		/* inode logging flags */
{
	xfs_btree_cur_t		*cur;		/* bmap btree cursor */
	int			error;		/* error return value */

	if (ip->i_d.di_nextents * sizeof(xfs_bmbt_rec_t) <= XFS_IFORK_DSIZE(ip))
		return 0;
	cur = NULL;
	error = xfs_bmap_extents_to_btree(tp, ip, firstblock, flist, &cur, 0,
		flags, XFS_DATA_FORK);
	if (cur) {
		cur->bc_private.b.allocated = 0;
		xfs_btree_del_cursor(cur,
			error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
	}
	return error;
}

/*
 * Called from xfs_bmap_add_attrfork to handle local format files.
 */
STATIC int					/* error */
xfs_bmap_add_attrfork_local(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode pointer */
	xfs_fsblock_t		*firstblock,	/* first block allocated */
	xfs_bmap_free_t		*flist,		/* blocks to free at commit */
	int			*flags)		/* inode logging flags */
{
	xfs_da_args_t		dargs;		/* args for dir/attr code */
	int			error;		/* error return value */
	xfs_mount_t		*mp;		/* mount structure pointer */

	if (ip->i_df.if_bytes <= XFS_IFORK_DSIZE(ip))
		return 0;
	if ((ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
		mp = ip->i_mount;
		memset(&dargs, 0, sizeof(dargs));
		dargs.dp = ip;
		dargs.firstblock = firstblock;
		dargs.flist = flist;
		dargs.total = mp->m_dirblkfsbs;
		dargs.whichfork = XFS_DATA_FORK;
		dargs.trans = tp;
		error = xfs_dir2_sf_to_block(&dargs);
	} else
		error = xfs_bmap_local_to_extents(tp, ip, firstblock, 1, flags,
			XFS_DATA_FORK);
	return error;
}

/*
 * Called by xfs_bmapi to update file extent records and the btree
 * after allocating space (or doing a delayed allocation).
 */
STATIC int				/* error */
xfs_bmap_add_extent(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		idx,	/* extent number to update/insert */
	xfs_btree_cur_t		**curp,	/* if *curp is null, not a btree */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	xfs_fsblock_t		*first,	/* pointer to firstblock variable */
	xfs_bmap_free_t		*flist,	/* list of extents to be freed */
	int			*logflagsp, /* inode logging flags */
	xfs_extdelta_t		*delta, /* Change made to incore extents */
	int			whichfork, /* data or attr fork */
	int			rsvd)	/* OK to use reserved data blocks */
{
	xfs_btree_cur_t		*cur;	/* btree cursor or null */
	xfs_filblks_t		da_new; /* new count del alloc blocks used */
	xfs_filblks_t		da_old; /* old count del alloc blocks used */
	int			error;	/* error return value */
	xfs_ifork_t		*ifp;	/* inode fork ptr */
	int			logflags; /* returned value */
	xfs_extnum_t		nextents; /* number of extents in file now */

	XFS_STATS_INC(xs_add_exlist);
	cur = *curp;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	ASSERT(idx <= nextents);
	da_old = da_new = 0;
	error = 0;
	/*
	 * This is the first extent added to a new/empty file.
	 * Special case this one, so other routines get to assume there are
	 * already extents in the list.
	 */
	if (nextents == 0) {
		XFS_BMAP_TRACE_INSERT("insert empty", ip, 0, 1, new, NULL,
			whichfork);
		xfs_iext_insert(ifp, 0, 1, new);
		ASSERT(cur == NULL);
		ifp->if_lastex = 0;
		if (!ISNULLSTARTBLOCK(new->br_startblock)) {
			XFS_IFORK_NEXT_SET(ip, whichfork, 1);
			logflags = XFS_ILOG_CORE | XFS_ILOG_FEXT(whichfork);
		} else
			logflags = 0;
		/* DELTA: single new extent */
		if (delta) {
			if (delta->xed_startoff > new->br_startoff)
				delta->xed_startoff = new->br_startoff;
			if (delta->xed_blockcount <
					new->br_startoff + new->br_blockcount)
				delta->xed_blockcount = new->br_startoff +
						new->br_blockcount;
		}
	}
	/*
	 * Any kind of new delayed allocation goes here.
	 */
	else if (ISNULLSTARTBLOCK(new->br_startblock)) {
		if (cur)
			ASSERT((cur->bc_private.b.flags &
				XFS_BTCUR_BPRV_WASDEL) == 0);
		if ((error = xfs_bmap_add_extent_hole_delay(ip, idx, new,
				&logflags, delta, rsvd)))
			goto done;
	}
	/*
	 * Real allocation off the end of the file.
	 */
	else if (idx == nextents) {
		if (cur)
			ASSERT((cur->bc_private.b.flags &
				XFS_BTCUR_BPRV_WASDEL) == 0);
		if ((error = xfs_bmap_add_extent_hole_real(ip, idx, cur, new,
				&logflags, delta, whichfork)))
			goto done;
	} else {
		xfs_bmbt_irec_t	prev;	/* old extent at offset idx */

		/*
		 * Get the record referred to by idx.
		 */
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, idx), &prev);
		/*
		 * If it's a real allocation record, and the new allocation ends
		 * after the start of the referred to record, then we're filling
		 * in a delayed or unwritten allocation with a real one, or
		 * converting real back to unwritten.
		 */
		if (!ISNULLSTARTBLOCK(new->br_startblock) &&
		    new->br_startoff + new->br_blockcount > prev.br_startoff) {
			if (prev.br_state != XFS_EXT_UNWRITTEN &&
			    ISNULLSTARTBLOCK(prev.br_startblock)) {
				da_old = STARTBLOCKVAL(prev.br_startblock);
				if (cur)
					ASSERT(cur->bc_private.b.flags &
						XFS_BTCUR_BPRV_WASDEL);
				if ((error = xfs_bmap_add_extent_delay_real(ip,
					idx, &cur, new, &da_new, first, flist,
					&logflags, delta, rsvd)))
					goto done;
			} else if (new->br_state == XFS_EXT_NORM) {
				ASSERT(new->br_state == XFS_EXT_NORM);
				if ((error = xfs_bmap_add_extent_unwritten_real(
					ip, idx, &cur, new, &logflags, delta)))
					goto done;
			} else {
				ASSERT(new->br_state == XFS_EXT_UNWRITTEN);
				if ((error = xfs_bmap_add_extent_unwritten_real(
					ip, idx, &cur, new, &logflags, delta)))
					goto done;
			}
			ASSERT(*curp == cur || *curp == NULL);
		}
		/*
		 * Otherwise we're filling in a hole with an allocation.
		 */
		else {
			if (cur)
				ASSERT((cur->bc_private.b.flags &
					XFS_BTCUR_BPRV_WASDEL) == 0);
			if ((error = xfs_bmap_add_extent_hole_real(ip, idx, cur,
					new, &logflags, delta, whichfork)))
				goto done;
		}
	}

	ASSERT(*curp == cur || *curp == NULL);
	/*
	 * Convert to a btree if necessary.
	 */
	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
	    XFS_IFORK_NEXTENTS(ip, whichfork) > ifp->if_ext_max) {
		int	tmp_logflags;	/* partial log flag return val */

		ASSERT(cur == NULL);
		error = xfs_bmap_extents_to_btree(ip->i_transp, ip, first,
			flist, &cur, da_old > 0, &tmp_logflags, whichfork);
		logflags |= tmp_logflags;
		if (error)
			goto done;
	}
	/*
	 * Adjust for changes in reserved delayed indirect blocks.
	 * Nothing to do for disk quotas here.
	 */
	if (da_old || da_new) {
		xfs_filblks_t	nblks;

		nblks = da_new;
		if (cur)
			nblks += cur->bc_private.b.allocated;
		ASSERT(nblks <= da_old);
		if (nblks < da_old)
			xfs_mod_incore_sb(ip->i_mount, XFS_SBS_FDBLOCKS,
				(int64_t)(da_old - nblks), rsvd);
	}
	/*
	 * Clear out the allocated field, done with it now in any case.
	 */
	if (cur) {
		cur->bc_private.b.allocated = 0;
		*curp = cur;
	}
done:
#ifdef DEBUG
	if (!error)
		xfs_bmap_check_leaf_extents(*curp, ip, whichfork);
#endif
	*logflagsp = logflags;
	return error;
}

/*
 * Called by xfs_bmap_add_extent to handle cases converting a delayed
 * allocation to a real allocation.
 */
STATIC int				/* error */
xfs_bmap_add_extent_delay_real(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		idx,	/* extent number to update/insert */
	xfs_btree_cur_t		**curp,	/* if *curp is null, not a btree */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	xfs_filblks_t		*dnew,	/* new delayed-alloc indirect blocks */
	xfs_fsblock_t		*first,	/* pointer to firstblock variable */
	xfs_bmap_free_t		*flist,	/* list of extents to be freed */
	int			*logflagsp, /* inode logging flags */
	xfs_extdelta_t		*delta, /* Change made to incore extents */
	int			rsvd)	/* OK to use reserved data block allocation */
{
	xfs_btree_cur_t		*cur;	/* btree cursor */
	int			diff;	/* temp value */
	xfs_bmbt_rec_host_t	*ep;	/* extent entry for idx */
	int			error;	/* error return value */
	int			i;	/* temp state */
	xfs_ifork_t		*ifp;	/* inode fork pointer */
	xfs_fileoff_t		new_endoff;	/* end offset of new entry */
	xfs_bmbt_irec_t		r[3];	/* neighbor extent entries */
					/* left is 0, right is 1, prev is 2 */
	int			rval=0;	/* return value (logging flags) */
	int			state = 0;/* state bits, accessed thru macros */
	xfs_filblks_t		temp=0;	/* value for dnew calculations */
	xfs_filblks_t		temp2=0;/* value for dnew calculations */
	int			tmp_rval;	/* partial logging flags */
	enum {				/* bit number definitions for state */
		LEFT_CONTIG,	RIGHT_CONTIG,
		LEFT_FILLING,	RIGHT_FILLING,
		LEFT_DELAY,	RIGHT_DELAY,
		LEFT_VALID,	RIGHT_VALID
	};

#define	LEFT		r[0]
#define	RIGHT		r[1]
#define	PREV		r[2]
#define	MASK(b)		(1 << (b))
#define	MASK2(a,b)	(MASK(a) | MASK(b))
#define	MASK3(a,b,c)	(MASK2(a,b) | MASK(c))
#define	MASK4(a,b,c,d)	(MASK3(a,b,c) | MASK(d))
#define	STATE_SET(b,v)	((v) ? (state |= MASK(b)) : (state &= ~MASK(b)))
#define	STATE_TEST(b)	(state & MASK(b))
#define	STATE_SET_TEST(b,v)	((v) ? ((state |= MASK(b)), 1) : \
				       ((state &= ~MASK(b)), 0))
#define	SWITCH_STATE		\
	(state & MASK4(LEFT_FILLING, RIGHT_FILLING, LEFT_CONTIG, RIGHT_CONTIG))

	/*
	 * Set up a bunch of variables to make the tests simpler.
	 */
	cur = *curp;
	ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
	ep = xfs_iext_get_ext(ifp, idx);
	xfs_bmbt_get_all(ep, &PREV);
	new_endoff = new->br_startoff + new->br_blockcount;
	ASSERT(PREV.br_startoff <= new->br_startoff);
	ASSERT(PREV.br_startoff + PREV.br_blockcount >= new_endoff);
	/*
	 * Set flags determining what part of the previous delayed allocation
	 * extent is being replaced by a real allocation.
	 */
	STATE_SET(LEFT_FILLING, PREV.br_startoff == new->br_startoff);
	STATE_SET(RIGHT_FILLING,
		PREV.br_startoff + PREV.br_blockcount == new_endoff);
	/*
	 * Check and set flags if this segment has a left neighbor.
	 * Don't set contiguous if the combined extent would be too large.
	 */
	if (STATE_SET_TEST(LEFT_VALID, idx > 0)) {
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, idx - 1), &LEFT);
		STATE_SET(LEFT_DELAY, ISNULLSTARTBLOCK(LEFT.br_startblock));
	}
	STATE_SET(LEFT_CONTIG,
		STATE_TEST(LEFT_VALID) && !STATE_TEST(LEFT_DELAY) &&
		LEFT.br_startoff + LEFT.br_blockcount == new->br_startoff &&
		LEFT.br_startblock + LEFT.br_blockcount == new->br_startblock &&
		LEFT.br_state == new->br_state &&
		LEFT.br_blockcount + new->br_blockcount <= MAXEXTLEN);
	/*
	 * Check and set flags if this segment has a right neighbor.
	 * Don't set contiguous if the combined extent would be too large.
	 * Also check for all-three-contiguous being too large.
	 */
	if (STATE_SET_TEST(RIGHT_VALID,
			idx <
			ip->i_df.if_bytes / (uint)sizeof(xfs_bmbt_rec_t) - 1)) {
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, idx + 1), &RIGHT);
		STATE_SET(RIGHT_DELAY, ISNULLSTARTBLOCK(RIGHT.br_startblock));
	}
	STATE_SET(RIGHT_CONTIG,
		STATE_TEST(RIGHT_VALID) && !STATE_TEST(RIGHT_DELAY) &&
		new_endoff == RIGHT.br_startoff &&
		new->br_startblock + new->br_blockcount ==
		    RIGHT.br_startblock &&
		new->br_state == RIGHT.br_state &&
		new->br_blockcount + RIGHT.br_blockcount <= MAXEXTLEN &&
		((state & MASK3(LEFT_CONTIG, LEFT_FILLING, RIGHT_FILLING)) !=
		  MASK3(LEFT_CONTIG, LEFT_FILLING, RIGHT_FILLING) ||
		 LEFT.br_blockcount + new->br_blockcount + RIGHT.br_blockcount
		     <= MAXEXTLEN));
	error = 0;
	/*
	 * Switch out based on the FILLING and CONTIG state bits.
	 */
	switch (SWITCH_STATE) {

	case MASK4(LEFT_FILLING, RIGHT_FILLING, LEFT_CONTIG, RIGHT_CONTIG):
		/*
		 * Filling in all of a previously delayed allocation extent.
		 * The left and right neighbors are both contiguous with new.
		 */
		XFS_BMAP_TRACE_PRE_UPDATE("LF|RF|LC|RC", ip, idx - 1,
			XFS_DATA_FORK);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, idx - 1),
			LEFT.br_blockcount + PREV.br_blockcount +
			RIGHT.br_blockcount);
		XFS_BMAP_TRACE_POST_UPDATE("LF|RF|LC|RC", ip, idx - 1,
			XFS_DATA_FORK);
		XFS_BMAP_TRACE_DELETE("LF|RF|LC|RC", ip, idx, 2, XFS_DATA_FORK);
		xfs_iext_remove(ifp, idx, 2);
		ip->i_df.if_lastex = idx - 1;
		ip->i_d.di_nextents--;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;