Commit 39269e29 authored by Nathan Scott's avatar Nathan Scott
Browse files

[XFS] Reduce xfs_bmapi stack use by removing some local state variables, 


and directly testing flags instead.

SGI-PV: 947312
SGI-Modid: xfs-linux-melb:xfs-kern:25370a

Signed-off-by: default avatarNathan Scott <nathans@sgi.com>
parent 220b5284

fs/xfs/xfs_bmap.c

+37 −42
Original line number Diff line number Diff line
@@ -4629,10 +4629,6 @@ xfs_bmapi( 
	xfs_btree_cur_t	*cur;		/* bmap btree cursor */

	xfs_fileoff_t	end;		/* end of mapped file region */

	int		eof;		/* we've hit the end of extents */

	char		contig;		/* allocation must be one extent */

	char		delay;		/* this request is for delayed alloc */

	char		exact;		/* don't do all of wasdelayed extent */

	char		convert;	/* unwritten extent I/O completion */

	xfs_bmbt_rec_t	*ep;		/* extent record pointer */

	int		error;		/* error return */

	xfs_bmbt_irec_t	got;		/* current file extent record */
@@ -4651,13 +4647,9 @@ xfs_bmapi( 
	int		tmp_logflags;	/* temp flags holder */

	int		whichfork;	/* data or attr fork */

	char		inhole;		/* current location is hole in file */

	char		stateless;	/* ignore state flag set */

	char		trim;		/* output trimmed to match range */

	char		userdata;	/* allocating non-metadata */

	char		wasdelay;	/* old extent was delayed */

	char		wr;		/* this is a write request */

	char		rt;		/* this is a realtime file */

	char		rsvd;		/* OK to allocate reserved blocks */

#ifdef DEBUG

	xfs_fileoff_t	orig_bno;	/* original block number value */

	int		orig_flags;	/* original flags arg value */
@@ -4694,15 +4686,8 @@ xfs_bmapi( 
		XFS_STATS_INC(xs_blk_mapw);

	else

		XFS_STATS_INC(xs_blk_mapr);

	delay = (flags & XFS_BMAPI_DELAY) != 0;

	trim = (flags & XFS_BMAPI_ENTIRE) == 0;

	userdata = (flags & XFS_BMAPI_METADATA) == 0;

	convert = (flags & XFS_BMAPI_CONVERT) != 0;

	exact = (flags & XFS_BMAPI_EXACT) != 0;

	rsvd = (flags & XFS_BMAPI_RSVBLOCKS) != 0;

	contig = (flags & XFS_BMAPI_CONTIG) != 0;

	/*

	 * stateless is used to combine extents which

	 * IGSTATE flag is used to combine extents which

	 * differ only due to the state of the extents.

	 * This technique is used from xfs_getbmap()

	 * when the caller does not wish to see the
@@ -4718,10 +4703,9 @@ xfs_bmapi( 
	 * xfs_strat_comp(), where the xfs_bmapi() call

	 * is transactioned, and the extents combined.

	 */

	stateless = (flags & XFS_BMAPI_IGSTATE) != 0;

	if (stateless && wr)	/* if writing unwritten space, no */

		wr = 0;		/* allocations are allowed */

	ASSERT(wr || !delay);

	if ((flags & XFS_BMAPI_IGSTATE) && wr)	/* if writing unwritten space */

		wr = 0;				/* no allocations are allowed */

	ASSERT(wr || !(flags & XFS_BMAPI_DELAY));

	logflags = 0;

	nallocs = 0;

	cur = NULL;
@@ -4756,7 +4740,7 @@ xfs_bmapi( 
		if (eof && !wr)

			got.br_startoff = end;

		inhole = eof || got.br_startoff > bno;

		wasdelay = wr && !inhole && !delay &&

		wasdelay = wr && !inhole && !(flags & XFS_BMAPI_DELAY) &&

			ISNULLSTARTBLOCK(got.br_startblock);

		/*

		 * First, deal with the hole before the allocated space
@@ -4768,7 +4752,7 @@ xfs_bmapi( 
			 * allocate the stuff asked for in this bmap call

			 * but that wouldn't be as good.

			 */

			if (wasdelay && !exact) {

			if (wasdelay && !(flags & XFS_BMAPI_EXACT)) {

				alen = (xfs_extlen_t)got.br_blockcount;

				aoff = got.br_startoff;

				if (lastx != NULLEXTNUM && lastx) {
@@ -4790,8 +4774,8 @@ xfs_bmapi( 
							got.br_startoff - bno);

				aoff = bno;

			}

			minlen = contig ? alen : 1;

			if (delay) {

			minlen = (flags & XFS_BMAPI_CONTIG) ? alen : 1;

			if (flags & XFS_BMAPI_DELAY) {

				xfs_extlen_t	extsz;



				/* Figure out the extent size, adjust alen */
@@ -4804,7 +4788,9 @@ xfs_bmapi( 
				if (extsz) {

					error = xfs_bmap_extsize_align(mp,

							&got, &prev, extsz,

							rt, eof, delay, convert,

							rt, eof,

							flags&XFS_BMAPI_DELAY,

							flags&XFS_BMAPI_CONVERT,

							&aoff, &alen);

					ASSERT(!error);

				}
@@ -4842,24 +4828,29 @@ xfs_bmapi( 
				if (rt) {

					error = xfs_mod_incore_sb(mp,

							XFS_SBS_FREXTENTS,

							-(extsz), rsvd);

							-(extsz), (flags &

							XFS_BMAPI_RSVBLOCKS));

				} else {

					error = xfs_mod_incore_sb(mp,

							XFS_SBS_FDBLOCKS,

							-(alen), rsvd);

							-(alen), (flags &

							XFS_BMAPI_RSVBLOCKS));

				}

				if (!error) {

					error = xfs_mod_incore_sb(mp,

							XFS_SBS_FDBLOCKS,

							-(indlen), rsvd);

							-(indlen), (flags &

							XFS_BMAPI_RSVBLOCKS));

					if (error && rt)

						xfs_mod_incore_sb(mp,

							XFS_SBS_FREXTENTS,

							extsz, rsvd);

							extsz, (flags &

							XFS_BMAPI_RSVBLOCKS));

					else if (error)

						xfs_mod_incore_sb(mp,

							XFS_SBS_FDBLOCKS,

							alen, rsvd);

							alen, (flags &

							XFS_BMAPI_RSVBLOCKS));

				}



				if (error) {
@@ -4892,7 +4883,7 @@ xfs_bmapi( 
				/* Indicate if this is the first user data

				 * in the file, or just any user data.

				 */

				if (userdata) {

				if (!(flags & XFS_BMAPI_METADATA)) {

					bma.userdata = (aoff == 0) ?

						XFS_ALLOC_INITIAL_USER_DATA :

						XFS_ALLOC_USERDATA;
@@ -4904,7 +4895,7 @@ xfs_bmapi( 
				bma.firstblock = *firstblock;

				bma.alen = alen;

				bma.off = aoff;

				bma.conv = convert;

				bma.conv = (flags & XFS_BMAPI_CONVERT);

				bma.wasdel = wasdelay;

				bma.minlen = minlen;

				bma.low = flist->xbf_low;
@@ -4915,7 +4906,8 @@ xfs_bmapi( 
				 * is larger than a stripe unit.

				 */

				if (mp->m_dalign && alen >= mp->m_dalign &&

				    userdata && whichfork == XFS_DATA_FORK) {

				    (!(flags & XFS_BMAPI_METADATA)) &&

				    (whichfork == XFS_DATA_FORK)) {

					if ((error = xfs_bmap_isaeof(ip, aoff,

							whichfork, &bma.aeof)))

						goto error0;
@@ -4978,7 +4970,7 @@ xfs_bmapi( 
			}

			error = xfs_bmap_add_extent(ip, lastx, &cur, &got,

				firstblock, flist, &tmp_logflags, whichfork,

				rsvd);

				(flags & XFS_BMAPI_RSVBLOCKS));

			logflags |= tmp_logflags;

			if (error)

				goto error0;
@@ -4990,7 +4982,7 @@ xfs_bmapi( 
			ASSERT(got.br_startoff + got.br_blockcount >=

				aoff + alen);

#ifdef DEBUG

			if (delay) {

			if (flags & XFS_BMAPI_DELAY) {

				ASSERT(ISNULLSTARTBLOCK(got.br_startblock));

				ASSERT(STARTBLOCKVAL(got.br_startblock) > 0);

			}
@@ -5019,14 +5011,15 @@ xfs_bmapi( 
		 * Then deal with the allocated space we found.

		 */

		ASSERT(ep != NULL);

		if (trim && (got.br_startoff + got.br_blockcount > obno)) {

		if (!(flags & XFS_BMAPI_ENTIRE) &&

		    (got.br_startoff + got.br_blockcount > obno)) {

			if (obno > bno)

				bno = obno;

			ASSERT((bno >= obno) || (n == 0));

			ASSERT(bno < end);

			mval->br_startoff = bno;

			if (ISNULLSTARTBLOCK(got.br_startblock)) {

				ASSERT(!wr || delay);

				ASSERT(!wr || (flags & XFS_BMAPI_DELAY));

				mval->br_startblock = DELAYSTARTBLOCK;

			} else

				mval->br_startblock =
@@ -5048,7 +5041,7 @@ xfs_bmapi( 
		} else {

			*mval = got;

			if (ISNULLSTARTBLOCK(mval->br_startblock)) {

				ASSERT(!wr || delay);

				ASSERT(!wr || (flags & XFS_BMAPI_DELAY));

				mval->br_startblock = DELAYSTARTBLOCK;

			}

		}
@@ -5074,7 +5067,7 @@ xfs_bmapi( 
			mval->br_state = XFS_EXT_NORM;

			error = xfs_bmap_add_extent(ip, lastx, &cur, mval,

				firstblock, flist, &tmp_logflags, whichfork,

				rsvd);

				(flags & XFS_BMAPI_RSVBLOCKS));

			logflags |= tmp_logflags;

			if (error)

				goto error0;
@@ -5091,9 +5084,10 @@ xfs_bmapi( 
				continue;

		}



		ASSERT(!trim ||

		ASSERT((flags & XFS_BMAPI_ENTIRE) ||

		       ((mval->br_startoff + mval->br_blockcount) <= end));

		ASSERT(!trim || (mval->br_blockcount <= len) ||

		ASSERT((flags & XFS_BMAPI_ENTIRE) ||

		       (mval->br_blockcount <= len) ||

		       (mval->br_startoff < obno));

		bno = mval->br_startoff + mval->br_blockcount;

		len = end - bno;
@@ -5108,7 +5102,8 @@ xfs_bmapi( 
			   mval[-1].br_startblock != HOLESTARTBLOCK &&

			   mval->br_startblock ==

			   mval[-1].br_startblock + mval[-1].br_blockcount &&

			   (stateless || mval[-1].br_state == mval->br_state)) {

			   ((flags & XFS_BMAPI_IGSTATE) ||

				mval[-1].br_state == mval->br_state)) {

			ASSERT(mval->br_startoff ==

			       mval[-1].br_startoff + mval[-1].br_blockcount);

			mval[-1].br_blockcount += mval->br_blockcount;