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Commit 55d6af64 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Ben Myers
Browse files

xfs: refactor xfs_ialloc_ag_select 



Loop over the in-core perag structures and prefer using pagi_freecount over
going out to the AGI buffer where possible.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarMark Tinguely <tinguely@sgi.com>
Signed-off-by: default avatarBen Myers <bpm@sgi.com>
parent 4bb61069

fs/xfs/xfs_ialloc.c

+44 −51
Original line number Diff line number Diff line
@@ -442,14 +442,13 @@ xfs_ialloc_next_ag( 
 * Select an allocation group to look for a free inode in, based on the parent

 * inode and then mode.  Return the allocation group buffer.

 */

STATIC xfs_buf_t *			/* allocation group buffer */

STATIC xfs_agnumber_t

xfs_ialloc_ag_select(

	xfs_trans_t	*tp,		/* transaction pointer */

	xfs_ino_t	parent,		/* parent directory inode number */

	umode_t		mode,		/* bits set to indicate file type */

	int		okalloc)	/* ok to allocate more space */

{

	xfs_buf_t	*agbp;		/* allocation group header buffer */

	xfs_agnumber_t	agcount;	/* number of ag's in the filesystem */

	xfs_agnumber_t	agno;		/* current ag number */

	int		flags;		/* alloc buffer locking flags */
@@ -459,6 +458,7 @@ xfs_ialloc_ag_select( 
	int		needspace;	/* file mode implies space allocated */

	xfs_perag_t	*pag;		/* per allocation group data */

	xfs_agnumber_t	pagno;		/* parent (starting) ag number */

	int		error;



	/*

	 * Files of these types need at least one block if length > 0
@@ -474,7 +474,9 @@ xfs_ialloc_ag_select( 
		if (pagno >= agcount)

			pagno = 0;

	}



	ASSERT(pagno < agcount);



	/*

	 * Loop through allocation groups, looking for one with a little

	 * free space in it.  Note we don't look for free inodes, exactly.
@@ -486,51 +488,45 @@ xfs_ialloc_ag_select( 
	flags = XFS_ALLOC_FLAG_TRYLOCK;

	for (;;) {

		pag = xfs_perag_get(mp, agno);

		if (!pag->pagi_init) {

			if (xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {

				agbp = NULL;

				goto nextag;

			}

		} else

			agbp = NULL;



		if (!pag->pagi_inodeok) {

			xfs_ialloc_next_ag(mp);

			goto unlock_nextag;

			goto nextag;

		}



		/*

		 * Is there enough free space for the file plus a block

		 * of inodes (if we need to allocate some)?

		 */

		ineed = pag->pagi_freecount ? 0 : XFS_IALLOC_BLOCKS(mp);

		if (ineed && !pag->pagf_init) {

			if (agbp == NULL &&

			    xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {

				agbp = NULL;

		if (!pag->pagi_init) {

			error = xfs_ialloc_pagi_init(mp, tp, agno);

			if (error)

				goto nextag;

		}

			(void)xfs_alloc_pagf_init(mp, tp, agno, flags);



		if (pag->pagi_freecount) {

			xfs_perag_put(pag);

			return agno;

		}

		if (!ineed || pag->pagf_init) {

			if (ineed && !(longest = pag->pagf_longest))

				longest = pag->pagf_flcount > 0;

			if (!ineed ||

			    (pag->pagf_freeblks >= needspace + ineed &&

			     longest >= ineed &&

			     okalloc)) {

				if (agbp == NULL &&

				    xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {

					agbp = NULL;



		if (!okalloc)

			goto nextag;



		if (!pag->pagf_init) {

			error = xfs_alloc_pagf_init(mp, tp, agno, flags);

			if (error)

				goto nextag;

		}



		/*

		 * Is there enough free space for the file plus a block of

		 * inodes? (if we need to allocate some)?

		 */

		ineed = XFS_IALLOC_BLOCKS(mp);

		longest = pag->pagf_longest;

		if (!longest)

			longest = pag->pagf_flcount > 0;



		if (pag->pagf_freeblks >= needspace + ineed &&

		    longest >= ineed) {

			xfs_perag_put(pag);

				return agbp;

			}

			return agno;

		}

unlock_nextag:

		if (agbp)

			xfs_trans_brelse(tp, agbp);

nextag:

		xfs_perag_put(pag);

		/*
@@ -538,13 +534,13 @@ nextag: 
		 * down.

		 */

		if (XFS_FORCED_SHUTDOWN(mp))

			return NULL;

			return NULLAGNUMBER;

		agno++;

		if (agno >= agcount)

			agno = 0;

		if (agno == pagno) {

			if (flags == 0)

				return NULL;

				return NULLAGNUMBER;

			flags = 0;

		}

	}
@@ -901,13 +897,13 @@ xfs_dialloc( 
	struct xfs_buf		**IO_agbp,

	xfs_ino_t		*inop)

{

	struct xfs_mount	*mp = tp->t_mountp;

	struct xfs_buf		*agbp;

	xfs_agnumber_t		agno;

	struct xfs_agi		*agi;

	int			error;

	int			ialloced;

	int			noroom = 0;

	struct xfs_mount	*mp;

	xfs_agnumber_t		tagno;

	struct xfs_perag	*pag;
@@ -925,20 +921,17 @@ xfs_dialloc( 
	 * We do not have an agbp, so select an initial allocation

	 * group for inode allocation.

	 */

	agbp = xfs_ialloc_ag_select(tp, parent, mode, okalloc);



	/*

	 * Couldn't find an allocation group satisfying the

	 * criteria, give up.

	 */

	if (!agbp) {

	agno = xfs_ialloc_ag_select(tp, parent, mode, okalloc);

	if (agno == NULLAGNUMBER) {

		*inop = NULLFSINO;

		return 0;

	}



	error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);

	if (error)

		return XFS_ERROR(error);

	agi = XFS_BUF_TO_AGI(agbp);



	mp = tp->t_mountp;

	agno = be32_to_cpu(agi->agi_seqno);

	tagno = agno;



	/*