Commit 76257a15 authored by Dave Chinner's avatar Dave Chinner
Browse files

xfs: introduce xfs_for_each_perag_wrap() 



In several places we iterate every AG from a specific start agno and
wrap back to the first AG when we reach the end of the filesystem to
continue searching. We don't have a primitive for this iteration
yet, so add one for conversion of these algorithms to per-ag based
iteration.

The filestream AG select code is a mess, and this initially makes it
worse. The per-ag selection needs to be driven completely into the
filestream code to clean this up and it will be done in a future
patch that makes the filestream allocator use active per-ag
references correctly.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent 7ac2ff8b

fs/xfs/libxfs/xfs_ag.h

+44 −1
Original line number Diff line number Diff line
@@ -237,7 +237,6 @@ xfs_perag_next( 
#define for_each_perag_from(mp, agno, pag) \

	for_each_perag_range((mp), (agno), (mp)->m_sb.sb_agcount - 1, (pag))





#define for_each_perag(mp, agno, pag) \

	(agno) = 0; \

	for_each_perag_from((mp), (agno), (pag))
@@ -249,6 +248,50 @@ xfs_perag_next( 
		xfs_perag_rele(pag), \

		(pag) = xfs_perag_grab_tag((mp), (agno), (tag)))



static inline struct xfs_perag *

xfs_perag_next_wrap(

	struct xfs_perag	*pag,

	xfs_agnumber_t		*agno,

	xfs_agnumber_t		stop_agno,

	xfs_agnumber_t		wrap_agno)

{

	struct xfs_mount	*mp = pag->pag_mount;



	*agno = pag->pag_agno + 1;

	xfs_perag_rele(pag);

	while (*agno != stop_agno) {

		if (*agno >= wrap_agno)

			*agno = 0;

		if (*agno == stop_agno)

			break;



		pag = xfs_perag_grab(mp, *agno);

		if (pag)

			return pag;

		(*agno)++;

	}

	return NULL;

}



/*

 * Iterate all AGs from start_agno through wrap_agno, then 0 through

 * (start_agno - 1).

 */

#define for_each_perag_wrap_at(mp, start_agno, wrap_agno, agno, pag) \

	for ((agno) = (start_agno), (pag) = xfs_perag_grab((mp), (agno)); \

		(pag) != NULL; \

		(pag) = xfs_perag_next_wrap((pag), &(agno), (start_agno), \

				(wrap_agno)))



/*

 * Iterate all AGs from start_agno through to the end of the filesystem, then 0

 * through (start_agno - 1).

 */

#define for_each_perag_wrap(mp, start_agno, agno, pag) \

	for_each_perag_wrap_at((mp), (start_agno), (mp)->m_sb.sb_agcount, \

				(agno), (pag))





struct aghdr_init_data {

	/* per ag data */

	xfs_agblock_t		agno;		/* ag to init */

fs/xfs/libxfs/xfs_bmap.c

+46 −32
Original line number Diff line number Diff line
@@ -3136,17 +3136,14 @@ xfs_bmap_adjacent( 


static int

xfs_bmap_longest_free_extent(

	struct xfs_perag	*pag,

	struct xfs_trans	*tp,

	xfs_agnumber_t		ag,

	xfs_extlen_t		*blen,

	int			*notinit)

{

	struct xfs_mount	*mp = tp->t_mountp;

	struct xfs_perag	*pag;

	xfs_extlen_t		longest;

	int			error = 0;



	pag = xfs_perag_get(mp, ag);

	if (!xfs_perag_initialised_agf(pag)) {

		error = xfs_alloc_read_agf(pag, tp, XFS_ALLOC_FLAG_TRYLOCK,

				NULL);
@@ -3156,19 +3153,17 @@ xfs_bmap_longest_free_extent( 
				*notinit = 1;

				error = 0;

			}

			goto out;

			return error;

		}

	}



	longest = xfs_alloc_longest_free_extent(pag,

				xfs_alloc_min_freelist(mp, pag),

				xfs_alloc_min_freelist(pag->pag_mount, pag),

				xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE));

	if (*blen < longest)

		*blen = longest;



out:

	xfs_perag_put(pag);

	return error;

	return 0;

}



static void
@@ -3206,9 +3201,10 @@ xfs_bmap_btalloc_select_lengths( 
	xfs_extlen_t		*blen)

{

	struct xfs_mount	*mp = ap->ip->i_mount;

	xfs_agnumber_t		ag, startag;

	struct xfs_perag	*pag;

	xfs_agnumber_t		agno, startag;

	int			notinit = 0;

	int			error;

	int			error = 0;



	args->type = XFS_ALLOCTYPE_START_BNO;

	if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
@@ -3218,24 +3214,24 @@ xfs_bmap_btalloc_select_lengths( 
	}



	args->total = ap->total;

	startag = ag = XFS_FSB_TO_AGNO(mp, args->fsbno);

	startag = XFS_FSB_TO_AGNO(mp, args->fsbno);

	if (startag == NULLAGNUMBER)

		startag = ag = 0;

		startag = 0;



	while (*blen < args->maxlen) {

		error = xfs_bmap_longest_free_extent(args->tp, ag, blen,

	*blen = 0;

	for_each_perag_wrap(mp, startag, agno, pag) {

		error = xfs_bmap_longest_free_extent(pag, args->tp, blen,

						     &notinit);

		if (error)

			return error;



		if (++ag == mp->m_sb.sb_agcount)

			ag = 0;

		if (ag == startag)

			break;

		if (*blen >= args->maxlen)

			break;

	}

	if (pag)

		xfs_perag_rele(pag);



	xfs_bmap_select_minlen(ap, args, blen, notinit);

	return 0;

	return error;

}



STATIC int
@@ -3245,7 +3241,8 @@ xfs_bmap_btalloc_filestreams( 
	xfs_extlen_t		*blen)

{

	struct xfs_mount	*mp = ap->ip->i_mount;

	xfs_agnumber_t		ag;

	struct xfs_perag	*pag;

	xfs_agnumber_t		start_agno;

	int			notinit = 0;

	int			error;
@@ -3259,33 +3256,50 @@ xfs_bmap_btalloc_filestreams( 
	args->type = XFS_ALLOCTYPE_NEAR_BNO;

	args->total = ap->total;



	ag = XFS_FSB_TO_AGNO(mp, args->fsbno);

	if (ag == NULLAGNUMBER)

		ag = 0;

	start_agno = XFS_FSB_TO_AGNO(mp, args->fsbno);

	if (start_agno == NULLAGNUMBER)

		start_agno = 0;



	error = xfs_bmap_longest_free_extent(args->tp, ag, blen, &notinit);

	pag = xfs_perag_grab(mp, start_agno);

	if (pag) {

		error = xfs_bmap_longest_free_extent(pag, args->tp, blen,

				&notinit);

		xfs_perag_rele(pag);

		if (error)

			return error;

	}



	if (*blen < args->maxlen) {

		error = xfs_filestream_new_ag(ap, &ag);

		xfs_agnumber_t	agno = start_agno;



		error = xfs_filestream_new_ag(ap, &agno);

		if (error)

			return error;

		if (agno == NULLAGNUMBER)

			goto out_select;



		error = xfs_bmap_longest_free_extent(args->tp, ag, blen,

						     &notinit);

		pag = xfs_perag_grab(mp, agno);

		if (!pag)

			goto out_select;



		error = xfs_bmap_longest_free_extent(pag, args->tp,

				blen, &notinit);

		xfs_perag_rele(pag);

		if (error)

			return error;



		start_agno = agno;



	}



out_select:

	xfs_bmap_select_minlen(ap, args, blen, notinit);



	/*

	 * Set the failure fallback case to look in the selected AG as stream

	 * may have moved.

	 */

	ap->blkno = args->fsbno = XFS_AGB_TO_FSB(mp, ag, 0);

	ap->blkno = args->fsbno = XFS_AGB_TO_FSB(mp, start_agno, 0);

	return 0;

}

fs/xfs/libxfs/xfs_ialloc.c

+15 −17
Original line number Diff line number Diff line
@@ -1725,7 +1725,7 @@ xfs_dialloc( 
	bool			ok_alloc = true;

	bool			low_space = false;

	int			flags;

	xfs_ino_t		ino;

	xfs_ino_t		ino = NULLFSINO;



	/*

	 * Directories, symlinks, and regular files frequently allocate at least
@@ -1773,39 +1773,37 @@ xfs_dialloc( 
	 * or in which we can allocate some inodes.  Iterate through the

	 * allocation groups upward, wrapping at the end.

	 */

	agno = start_agno;

	flags = XFS_ALLOC_FLAG_TRYLOCK;

	for (;;) {

		pag = xfs_perag_grab(mp, agno);

retry:

	for_each_perag_wrap_at(mp, start_agno, mp->m_maxagi, agno, pag) {

		if (xfs_dialloc_good_ag(pag, *tpp, mode, flags, ok_alloc)) {

			error = xfs_dialloc_try_ag(pag, tpp, parent,

					&ino, ok_alloc);

			if (error != -EAGAIN)

				break;

			error = 0;

		}



		if (xfs_is_shutdown(mp)) {

			error = -EFSCORRUPTED;

			break;

		}

		if (++agno == mp->m_maxagi)

			agno = 0;

		if (agno == start_agno) {

			if (!flags) {

				error = -ENOSPC;

				break;

	}

	if (pag)

		xfs_perag_rele(pag);

	if (error)

		return error;

	if (ino == NULLFSINO) {

		if (flags) {

			flags = 0;

			if (low_space)

				ok_alloc = true;

			goto retry;

		}

		xfs_perag_rele(pag);

		return -ENOSPC;

	}



	if (!error)

	*new_ino = ino;

	xfs_perag_rele(pag);

	return error;

	return 0;

}



/*