Commit a365bdd5 authored by Nathan Scott's avatar Nathan Scott
Browse files

[XFS] Reduce stack usage within xfs_bmapi by rearranging some code, 


splitting realtime/btree allocators apart.  Based on Glens original
patches.

SGI-PV: 947312
SGI-Modid: xfs-linux-melb:xfs-kern:25372a

Signed-off-by: default avatarNathan Scott <nathans@sgi.com>
parent 39269e29

fs/xfs/xfs_bmap.c

+345 −323
Original line number Diff line number Diff line
@@ -2294,25 +2294,15 @@ xfs_bmap_extsize_align( 


#define XFS_ALLOC_GAP_UNITS	4



/*

 * xfs_bmap_alloc is called by xfs_bmapi to allocate an extent for a file.

 * It figures out where to ask the underlying allocator to put the new extent.

 */

STATIC int

xfs_bmap_alloc(

xfs_bmap_adjacent(

	xfs_bmalloca_t	*ap)		/* bmap alloc argument struct */

{

	xfs_fsblock_t	adjust;		/* adjustment to block numbers */

	xfs_alloctype_t	atype=0;	/* type for allocation routines */

	int		error;		/* error return value */

	xfs_agnumber_t	fb_agno;	/* ag number of ap->firstblock */

	xfs_mount_t	*mp;		/* mount point structure */

	int		nullfb;		/* true if ap->firstblock isn't set */

	int		rt;		/* true if inode is realtime */

	xfs_extlen_t	prod = 0;	/* product factor for allocators */

	xfs_extlen_t	ralen = 0;	/* realtime allocation length */

	xfs_extlen_t	align;		/* minimum allocation alignment */

	xfs_rtblock_t	rtx;



#define	ISVALID(x,y)	\

	(rt ? \
@@ -2321,75 +2311,10 @@ xfs_bmap_alloc( 
		XFS_FSB_TO_AGNO(mp, x) < mp->m_sb.sb_agcount && \

		XFS_FSB_TO_AGBNO(mp, x) < mp->m_sb.sb_agblocks)



	/*

	 * Set up variables.

	 */

	mp = ap->ip->i_mount;

	nullfb = ap->firstblock == NULLFSBLOCK;

	rt = XFS_IS_REALTIME_INODE(ap->ip) && ap->userdata;

	fb_agno = nullfb ? NULLAGNUMBER : XFS_FSB_TO_AGNO(mp, ap->firstblock);

	if (rt) {

		align = ap->ip->i_d.di_extsize ?

			ap->ip->i_d.di_extsize : mp->m_sb.sb_rextsize;

		/* Set prod to match the extent size */

		prod = align / mp->m_sb.sb_rextsize;



		error = xfs_bmap_extsize_align(mp, ap->gotp, ap->prevp,

						align, rt, ap->eof, 0,

						ap->conv, &ap->off, &ap->alen);

		if (error)

			return error;

		ASSERT(ap->alen);

		ASSERT(ap->alen % mp->m_sb.sb_rextsize == 0);



		/*

		 * If the offset & length are not perfectly aligned

		 * then kill prod, it will just get us in trouble.

		 */

		if (do_mod(ap->off, align) || ap->alen % align)

			prod = 1;

		/*

		 * Set ralen to be the actual requested length in rtextents.

		 */

		ralen = ap->alen / mp->m_sb.sb_rextsize;

		/*

		 * If the old value was close enough to MAXEXTLEN that

		 * we rounded up to it, cut it back so it's valid again.

		 * Note that if it's a really large request (bigger than

		 * MAXEXTLEN), we don't hear about that number, and can't

		 * adjust the starting point to match it.

		 */

		if (ralen * mp->m_sb.sb_rextsize >= MAXEXTLEN)

			ralen = MAXEXTLEN / mp->m_sb.sb_rextsize;

		/*

		 * If it's an allocation to an empty file at offset 0,

		 * pick an extent that will space things out in the rt area.

		 */

		if (ap->eof && ap->off == 0) {

			error = xfs_rtpick_extent(mp, ap->tp, ralen, &rtx);

			if (error)

				return error;

			ap->rval = rtx * mp->m_sb.sb_rextsize;

		} else

			ap->rval = 0;

	} else {

		align = (ap->userdata && ap->ip->i_d.di_extsize &&

			(ap->ip->i_d.di_flags & XFS_DIFLAG_EXTSIZE)) ?

			ap->ip->i_d.di_extsize : 0;

		if (unlikely(align)) {

			error = xfs_bmap_extsize_align(mp, ap->gotp, ap->prevp,

							align, rt,

							ap->eof, 0, ap->conv,

							&ap->off, &ap->alen);

			ASSERT(!error);

			ASSERT(ap->alen);

		}

		if (nullfb)

			ap->rval = XFS_INO_TO_FSB(mp, ap->ip->i_ino);

		else

			ap->rval = ap->firstblock;

	}



	/*

	 * If allocating at eof, and there's a previous real block,

	 * try to use it's last block as our starting point.
@@ -2514,25 +2439,73 @@ xfs_bmap_alloc( 
		else if (gotbno != NULLFSBLOCK)

			ap->rval = gotbno;

	}

#undef ISVALID

	return 0;

}



STATIC int

xfs_bmap_rtalloc(

	xfs_bmalloca_t	*ap)		/* bmap alloc argument struct */

{

	xfs_alloctype_t	atype = 0;	/* type for allocation routines */

	int		error;		/* error return value */

	xfs_mount_t	*mp;		/* mount point structure */

	xfs_extlen_t	prod = 0;	/* product factor for allocators */

	xfs_extlen_t	ralen = 0;	/* realtime allocation length */

	xfs_extlen_t	align;		/* minimum allocation alignment */

	xfs_rtblock_t	rtx;		/* realtime extent number */

	xfs_rtblock_t	rtb;



	mp = ap->ip->i_mount;

	align = ap->ip->i_d.di_extsize ?

		ap->ip->i_d.di_extsize : mp->m_sb.sb_rextsize;

	prod = align / mp->m_sb.sb_rextsize;

	error = xfs_bmap_extsize_align(mp, ap->gotp, ap->prevp,

					align, 1, ap->eof, 0,

					ap->conv, &ap->off, &ap->alen);

	if (error)

		return error;

	ASSERT(ap->alen);

	ASSERT(ap->alen % mp->m_sb.sb_rextsize == 0);



	/*

	 * If allowed, use ap->rval; otherwise must use firstblock since

	 * it's in the right allocation group.

	 * If the offset & length are not perfectly aligned

	 * then kill prod, it will just get us in trouble.

	 */

	if (nullfb || rt || XFS_FSB_TO_AGNO(mp, ap->rval) == fb_agno)

		;

	else

		ap->rval = ap->firstblock;

	if (do_mod(ap->off, align) || ap->alen % align)

		prod = 1;

	/*

	 * Realtime allocation, done through xfs_rtallocate_extent.

	 * Set ralen to be the actual requested length in rtextents.

	 */

	if (rt) {

#ifndef __KERNEL__

		ASSERT(0);

#else

		xfs_rtblock_t	rtb;

	ralen = ap->alen / mp->m_sb.sb_rextsize;

	/*

	 * If the old value was close enough to MAXEXTLEN that

	 * we rounded up to it, cut it back so it's valid again.

	 * Note that if it's a really large request (bigger than

	 * MAXEXTLEN), we don't hear about that number, and can't

	 * adjust the starting point to match it.

	 */

	if (ralen * mp->m_sb.sb_rextsize >= MAXEXTLEN)

		ralen = MAXEXTLEN / mp->m_sb.sb_rextsize;

	/*

	 * If it's an allocation to an empty file at offset 0,

	 * pick an extent that will space things out in the rt area.

	 */

	if (ap->eof && ap->off == 0) {

		error = xfs_rtpick_extent(mp, ap->tp, ralen, &rtx);

		if (error)

			return error;

		ap->rval = rtx * mp->m_sb.sb_rextsize;

	} else {

		ap->rval = 0;

	}



		atype = ap->rval == 0 ?

			XFS_ALLOCTYPE_ANY_AG : XFS_ALLOCTYPE_NEAR_BNO;

	xfs_bmap_adjacent(ap);



	/*

	 * Realtime allocation, done through xfs_rtallocate_extent.

	 */

	atype = ap->rval == 0 ?  XFS_ALLOCTYPE_ANY_AG : XFS_ALLOCTYPE_NEAR_BNO;

	do_div(ap->rval, mp->m_sb.sb_rextsize);

	rtb = ap->rval;

	ap->alen = ralen;
@@ -2559,29 +2532,67 @@ xfs_bmap_alloc( 
		 */

		XFS_TRANS_MOD_DQUOT_BYINO(mp, ap->tp, ap->ip,

			ap->wasdel ? XFS_TRANS_DQ_DELRTBCOUNT :

						XFS_TRANS_DQ_RTBCOUNT,

				(long) ralen);

		} else

					XFS_TRANS_DQ_RTBCOUNT, (long) ralen);

	} else {

		ap->alen = 0;

#endif	/* __KERNEL__ */

	}

	/*

	 * Normal allocation, done through xfs_alloc_vextent.

	 */

	else {

	return 0;

}



STATIC int

xfs_bmap_btalloc(

	xfs_bmalloca_t	*ap)		/* bmap alloc argument struct */

{

	xfs_mount_t	*mp;		/* mount point structure */

	xfs_alloctype_t	atype = 0;	/* type for allocation routines */

	xfs_extlen_t	align;		/* minimum allocation alignment */

	xfs_agnumber_t	ag;

	xfs_agnumber_t	fb_agno;	/* ag number of ap->firstblock */

	xfs_agnumber_t	startag;

	xfs_alloc_arg_t	args;

	xfs_extlen_t	blen;

	xfs_extlen_t	delta;

		int		isaligned;

	xfs_extlen_t	longest;

	xfs_extlen_t	need;

	xfs_extlen_t	nextminlen = 0;

		int		notinit;

	xfs_perag_t	*pag;

		xfs_agnumber_t	startag;

	int		nullfb;		/* true if ap->firstblock isn't set */

	int		isaligned;

	int		notinit;

	int		tryagain;

	int		error;



	mp = ap->ip->i_mount;

	align = (ap->userdata && ap->ip->i_d.di_extsize &&

		(ap->ip->i_d.di_flags & XFS_DIFLAG_EXTSIZE)) ?

		ap->ip->i_d.di_extsize : 0;

	if (unlikely(align)) {

		error = xfs_bmap_extsize_align(mp, ap->gotp, ap->prevp,

						align, 0, ap->eof, 0, ap->conv,

						&ap->off, &ap->alen);

		ASSERT(!error);

		ASSERT(ap->alen);

	}

	nullfb = ap->firstblock == NULLFSBLOCK;

	fb_agno = nullfb ? NULLAGNUMBER : XFS_FSB_TO_AGNO(mp, ap->firstblock);

	if (nullfb)

		ap->rval = XFS_INO_TO_FSB(mp, ap->ip->i_ino);

	else

		ap->rval = ap->firstblock;



	xfs_bmap_adjacent(ap);



	/*

	 * If allowed, use ap->rval; otherwise must use firstblock since

	 * it's in the right allocation group.

	 */

	if (nullfb || XFS_FSB_TO_AGNO(mp, ap->rval) == fb_agno)

		;

	else

		ap->rval = ap->firstblock;

	/*

	 * Normal allocation, done through xfs_alloc_vextent.

	 */

	tryagain = isaligned = 0;

	args.tp = ap->tp;

	args.mp = mp;
@@ -2786,9 +2797,20 @@ xfs_bmap_alloc( 
		ap->rval = NULLFSBLOCK;

		ap->alen = 0;

	}

	}

	return 0;

#undef	ISVALID

}



/*

 * xfs_bmap_alloc is called by xfs_bmapi to allocate an extent for a file.

 * It figures out where to ask the underlying allocator to put the new extent.

 */

STATIC int

xfs_bmap_alloc(

	xfs_bmalloca_t	*ap)		/* bmap alloc argument struct */

{

	if ((ap->ip->i_d.di_flags & XFS_DIFLAG_REALTIME) && ap->userdata)

		return xfs_bmap_rtalloc(ap);

	return xfs_bmap_btalloc(ap);

}



/*