Commit 3054face authored by Dave Chinner's avatar Dave Chinner
Browse files

xfs: track an active perag reference in filestreams 



Rather than just track the agno of the reference, track a referenced
perag pointer instead. This will allow active filestreams to prevent
AGs from going away until the filestreams have been torn down.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent f38b46bb

fs/xfs/xfs_filestream.c

+43 −57
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ 


struct xfs_fstrm_item {

	struct xfs_mru_cache_elem	mru;

	xfs_agnumber_t			ag; /* AG in use for this directory */

	struct xfs_perag		*pag; /* AG in use for this directory */

};



enum xfs_fstrm_alloc {
@@ -50,43 +50,18 @@ xfs_filestream_peek_ag( 
	return ret;

}



static int

xfs_filestream_get_ag(

	xfs_mount_t	*mp,

	xfs_agnumber_t	agno)

{

	struct xfs_perag *pag;

	int		ret;



	pag = xfs_perag_get(mp, agno);

	ret = atomic_inc_return(&pag->pagf_fstrms);

	xfs_perag_put(pag);

	return ret;

}



static void

xfs_filestream_put_ag(

	xfs_mount_t	*mp,

	xfs_agnumber_t	agno)

{

	struct xfs_perag *pag;



	pag = xfs_perag_get(mp, agno);

	atomic_dec(&pag->pagf_fstrms);

	xfs_perag_put(pag);

}



static void

xfs_fstrm_free_func(

	void			*data,

	struct xfs_mru_cache_elem *mru)

{

	struct xfs_mount	*mp = data;

	struct xfs_fstrm_item	*item =

		container_of(mru, struct xfs_fstrm_item, mru);

	struct xfs_perag	*pag = item->pag;



	xfs_filestream_put_ag(mp, item->ag);

	trace_xfs_filestream_free(mp, mru->key, item->ag);

	trace_xfs_filestream_free(pag->pag_mount, mru->key, pag->pag_agno);

	atomic_dec(&pag->pagf_fstrms);

	xfs_perag_rele(pag);



	kmem_free(item);

}
@@ -105,11 +80,11 @@ xfs_filestream_pick_ag( 
	struct xfs_mount	*mp = ip->i_mount;

	struct xfs_fstrm_item	*item;

	struct xfs_perag	*pag;

	struct xfs_perag	*max_pag = NULL;

	xfs_extlen_t		minlen = *longest;

	xfs_extlen_t		free = 0, minfree, maxfree = 0;

	xfs_agnumber_t		startag = *agp;

	xfs_agnumber_t		ag = startag;

	xfs_agnumber_t		max_ag = NULLAGNUMBER;

	int			err, trylock, nscan;



	ASSERT(S_ISDIR(VFS_I(ip)->i_mode));
@@ -125,13 +100,16 @@ xfs_filestream_pick_ag( 
	for (nscan = 0; 1; nscan++) {

		trace_xfs_filestream_scan(mp, ip->i_ino, ag);



		pag = xfs_perag_get(mp, ag);

		err = 0;

		pag = xfs_perag_grab(mp, ag);

		if (!pag)

			goto next_ag;

		*longest = 0;

		err = xfs_bmap_longest_free_extent(pag, NULL, longest);

		if (err) {

			xfs_perag_put(pag);

			xfs_perag_rele(pag);

			if (err != -EAGAIN)

				return err;

				break;

			/* Couldn't lock the AGF, skip this AG. */

			goto next_ag;

		}
@@ -139,7 +117,10 @@ xfs_filestream_pick_ag( 
		/* Keep track of the AG with the most free blocks. */

		if (pag->pagf_freeblks > maxfree) {

			maxfree = pag->pagf_freeblks;

			max_ag = ag;

			if (max_pag)

				xfs_perag_rele(max_pag);

			atomic_inc(&pag->pag_active_ref);

			max_pag = pag;

		}



		/*
@@ -148,8 +129,9 @@ xfs_filestream_pick_ag( 
		 * loop, and it guards against two filestreams being established

		 * in the same AG as each other.

		 */

		if (xfs_filestream_get_ag(mp, ag) > 1) {

			xfs_filestream_put_ag(mp, ag);

		if (atomic_inc_return(&pag->pagf_fstrms) > 1) {

			atomic_dec(&pag->pagf_fstrms);

			xfs_perag_rele(pag);

			goto next_ag;

		}
@@ -161,15 +143,12 @@ xfs_filestream_pick_ag( 


			/* Break out, retaining the reference on the AG. */

			free = pag->pagf_freeblks;

			xfs_perag_put(pag);

			*agp = ag;

			break;

		}



		/* Drop the reference on this AG, it's not usable. */

		xfs_filestream_put_ag(mp, ag);

		atomic_dec(&pag->pagf_fstrms);

next_ag:

		xfs_perag_put(pag);

		/* Move to the next AG, wrapping to AG 0 if necessary. */

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

			ag = 0;
@@ -194,10 +173,10 @@ xfs_filestream_pick_ag( 
		 * Take the AG with the most free space, regardless of whether

		 * it's already in use by another filestream.

		 */

		if (max_ag != NULLAGNUMBER) {

			xfs_filestream_get_ag(mp, max_ag);

		if (max_pag) {

			pag = max_pag;

			atomic_inc(&pag->pagf_fstrms);

			free = maxfree;

			*agp = max_ag;

			break;

		}
@@ -207,17 +186,26 @@ xfs_filestream_pick_ag( 
		return 0;

	}



	trace_xfs_filestream_pick(ip, *agp, free, nscan);

	trace_xfs_filestream_pick(ip, pag ? pag->pag_agno : NULLAGNUMBER,

			free, nscan);



	if (max_pag)

		xfs_perag_rele(max_pag);



	if (err)

		return err;



	if (*agp == NULLAGNUMBER)

	if (!pag) {

		*agp = NULLAGNUMBER;

		return 0;

	}



	err = -ENOMEM;

	item = kmem_alloc(sizeof(*item), KM_MAYFAIL);

	if (!item)

		goto out_put_ag;



	item->ag = *agp;

	item->pag = pag;



	err = xfs_mru_cache_insert(mp->m_filestream, ip->i_ino, &item->mru);

	if (err) {
@@ -226,12 +214,14 @@ xfs_filestream_pick_ag( 
		goto out_free_item;

	}



	*agp = pag->pag_agno;

	return 0;



out_free_item:

	kmem_free(item);

out_put_ag:

	xfs_filestream_put_ag(mp, *agp);

	atomic_dec(&pag->pagf_fstrms);

	xfs_perag_rele(pag);

	return err;

}
@@ -284,20 +274,15 @@ xfs_filestream_select_ag_mru( 
	if (!mru)

		goto out_default_agno;



	*agno = container_of(mru, struct xfs_fstrm_item, mru)->ag;

	pag = container_of(mru, struct xfs_fstrm_item, mru)->pag;

	xfs_mru_cache_done(mp->m_filestream);



	trace_xfs_filestream_lookup(mp, ap->ip->i_ino, *agno);

	trace_xfs_filestream_lookup(mp, ap->ip->i_ino, pag->pag_agno);



	ap->blkno = XFS_AGB_TO_FSB(args->mp, *agno, 0);

	ap->blkno = XFS_AGB_TO_FSB(args->mp, pag->pag_agno, 0);

	xfs_bmap_adjacent(ap);



	pag = xfs_perag_grab(mp, *agno);

	if (!pag)

		goto out_default_agno;



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

	xfs_perag_rele(pag);

	if (error) {

		if (error != -EAGAIN)

			return error;
@@ -307,6 +292,7 @@ xfs_filestream_select_ag_mru( 
	/*

	 * We are done if there's still enough contiguous free space to succeed.

	 */

	*agno = pag->pag_agno;

	if (*blen >= args->maxlen)

		return 0;
@@ -315,7 +301,7 @@ xfs_filestream_select_ag_mru( 
	if (mru) {

		struct xfs_fstrm_item *item =

			container_of(mru, struct xfs_fstrm_item, mru);

		*agno = (item->ag + 1) % mp->m_sb.sb_agcount;

		*agno = (item->pag->pag_agno + 1) % mp->m_sb.sb_agcount;

		xfs_fstrm_free_func(mp, mru);

		return 0;

	}