Commit 50adbcb4 authored by Dave Chinner's avatar Dave Chinner Committed by Dave Chinner
Browse files

xfs: xfs_alloc_fix_freelist() can use incore perag structures 



At the moment, xfs_alloc_fix_freelist() uses a mix of per-ag based
access and agf buffer  based access to freelist and space usage
information. However, once the AGF buffer is locked inside this
function, it is guaranteed that both the in-memory and on-disk
values are identical. xfs_alloc_fix_freelist() doesn't modify the
values in the structures directly, so it is a read-only user of the
infomration, and hence can use the per-ag structure exclusively for
determining what it should do.

This opens up an avenue for cleaning up a lot of duplicated logic
whose only difference is the structure it gets the data from, and in
doing so removes a lot of needless byte swapping overhead when
fixing up the free list.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent 5ebe6afa

fs/xfs/libxfs/xfs_alloc.c

+31 −38
Original line number Diff line number Diff line
@@ -1825,11 +1825,11 @@ xfs_alloc_compute_maxlevels( 
xfs_extlen_t

xfs_alloc_longest_free_extent(

	struct xfs_mount	*mp,

	struct xfs_perag	*pag)

	struct xfs_perag	*pag,

	xfs_extlen_t		need)

{

	xfs_extlen_t		need, delta = 0;

	xfs_extlen_t		delta = 0;



	need = XFS_MIN_FREELIST_PAG(pag, mp);

	if (need > pag->pagf_flcount)

		delta = need - pag->pagf_flcount;
@@ -1848,10 +1848,8 @@ xfs_alloc_fix_freelist( 
	int		flags)	/* XFS_ALLOC_FLAG_... */

{

	xfs_buf_t	*agbp;	/* agf buffer pointer */

	xfs_agf_t	*agf;	/* a.g. freespace structure pointer */

	xfs_buf_t	*agflbp;/* agfl buffer pointer */

	xfs_agblock_t	bno;	/* freelist block */

	xfs_extlen_t	delta;	/* new blocks needed in freelist */

	int		error;	/* error result code */

	xfs_extlen_t	longest;/* longest extent in allocation group */

	xfs_mount_t	*mp;	/* file system mount point structure */
@@ -1895,7 +1893,7 @@ xfs_alloc_fix_freelist( 
		 * total blocks, reject it.

		 */

		need = XFS_MIN_FREELIST_PAG(pag, mp);

		longest = xfs_alloc_longest_free_extent(mp, pag);

		longest = xfs_alloc_longest_free_extent(mp, pag, need);

		if ((args->minlen + args->alignment + args->minalignslop - 1) >

				longest ||

		    ((int)(pag->pagf_freeblks + pag->pagf_flcount -
@@ -1922,25 +1920,16 @@ xfs_alloc_fix_freelist( 
			return 0;

		}

	}

	/*

	 * Figure out how many blocks we should have in the freelist.

	 */

	agf = XFS_BUF_TO_AGF(agbp);

	need = XFS_MIN_FREELIST(agf, mp);

	/*

	 * If there isn't enough total or single-extent, reject it.

	 */





	/* If there isn't enough total space or single-extent, reject it. */

	need = XFS_MIN_FREELIST_PAG(pag, mp);

	if (!(flags & XFS_ALLOC_FLAG_FREEING)) {

		delta = need > be32_to_cpu(agf->agf_flcount) ?

			(need - be32_to_cpu(agf->agf_flcount)) : 0;

		longest = be32_to_cpu(agf->agf_longest);

		longest = (longest > delta) ? (longest - delta) :

			(be32_to_cpu(agf->agf_flcount) > 0 || longest > 0);

		longest = xfs_alloc_longest_free_extent(mp, pag, need);

		if ((args->minlen + args->alignment + args->minalignslop - 1) >

				longest ||

		    ((int)(be32_to_cpu(agf->agf_freeblks) +

		     be32_to_cpu(agf->agf_flcount) - need - args->total) <

				(int)args->minleft)) {

		    ((int)(pag->pagf_freeblks + pag->pagf_flcount -

			   need - args->total) < (int)args->minleft)) {

			xfs_trans_brelse(tp, agbp);

			args->agbp = NULL;

			return 0;
@@ -1948,21 +1937,25 @@ xfs_alloc_fix_freelist( 
	}

	/*

	 * Make the freelist shorter if it's too long.

	 *

	 * XXX (dgc): When we have lots of free space, does this buy us

	 * anything other than extra overhead when we need to put more blocks

	 * back on the free list? Maybe we should only do this when space is

	 * getting low or the AGFL is more than half full?

	 */

	while (be32_to_cpu(agf->agf_flcount) > need) {

		xfs_buf_t	*bp;

	while (pag->pagf_flcount > need) {

		struct xfs_buf	*bp;



		error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);

		if (error)

			return error;

		if ((error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1)))

		error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1);

		if (error)

			return error;

		bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);

		xfs_trans_binval(tp, bp);

	}

	/*

	 * Initialize the args structure.

	 */



	memset(&targs, 0, sizeof(targs));

	targs.tp = tp;

	targs.mp = mp;
@@ -1971,18 +1964,18 @@ xfs_alloc_fix_freelist( 
	targs.alignment = targs.minlen = targs.prod = targs.isfl = 1;

	targs.type = XFS_ALLOCTYPE_THIS_AG;

	targs.pag = pag;

	if ((error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp)))

	error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp);

	if (error)

		return error;

	/*

	 * Make the freelist longer if it's too short.

	 */

	while (be32_to_cpu(agf->agf_flcount) < need) {



	/* Make the freelist longer if it's too short. */

	while (pag->pagf_flcount < need) {

		targs.agbno = 0;

		targs.maxlen = need - be32_to_cpu(agf->agf_flcount);

		/*

		 * Allocate as many blocks as possible at once.

		 */

		if ((error = xfs_alloc_ag_vextent(&targs))) {

		targs.maxlen = need - pag->pagf_flcount;



		/* Allocate as many blocks as possible at once. */

		error = xfs_alloc_ag_vextent(&targs);

		if (error) {

			xfs_trans_brelse(tp, agflbp);

			return error;

		}

fs/xfs/libxfs/xfs_alloc.h

+2 −6
Original line number Diff line number Diff line
@@ -128,12 +128,8 @@ typedef struct xfs_alloc_arg { 
#define XFS_ALLOC_USERDATA		1	/* allocation is for user data*/

#define XFS_ALLOC_INITIAL_USER_DATA	2	/* special case start of file */



/*

 * Find the length of the longest extent in an AG.

 */

xfs_extlen_t

xfs_alloc_longest_free_extent(struct xfs_mount *mp,

		struct xfs_perag *pag);

xfs_extlen_t xfs_alloc_longest_free_extent(struct xfs_mount *mp,

		struct xfs_perag *pag, xfs_extlen_t need);



/*

 * Compute and fill in value of m_ag_maxlevels.

fs/xfs/libxfs/xfs_bmap.c

+2 −1
Original line number Diff line number Diff line
@@ -3507,7 +3507,8 @@ xfs_bmap_longest_free_extent( 
		}

	}



	longest = xfs_alloc_longest_free_extent(mp, pag);

	longest = xfs_alloc_longest_free_extent(mp, pag,

						XFS_MIN_FREELIST_PAG(pag, mp));

	if (*blen < longest)

		*blen = longest;

fs/xfs/xfs_filestream.c

+2 −1
Original line number Diff line number Diff line
@@ -196,7 +196,8 @@ xfs_filestream_pick_ag( 
			goto next_ag;

		}



		longest = xfs_alloc_longest_free_extent(mp, pag);

		longest = xfs_alloc_longest_free_extent(mp, pag,

						XFS_MIN_FREELIST_PAG(pag, mp));

		if (((minlen && longest >= minlen) ||

		     (!minlen && pag->pagf_freeblks >= minfree)) &&

		    (!pag->pagf_metadata || !(flags & XFS_PICK_USERDATA) ||

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