Commit f48e2df8 authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: make xfs_*read_agf return EAGAIN to ALLOC_FLAG_TRYLOCK callers 



Refactor xfs_read_agf and xfs_alloc_read_agf to return EAGAIN if the
caller passed TRYLOCK and we weren't able to get the lock; and change
the callers to recognize this.

Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
parent ee647f85

fs/xfs/libxfs/xfs_alloc.c

+14 −22
Original line number Diff line number Diff line
@@ -2502,12 +2502,11 @@ xfs_alloc_fix_freelist( 


	if (!pag->pagf_init) {

		error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);

		if (error)

		if (error) {

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

			if (error == -EAGAIN)

				error = 0;

			goto out_no_agbp;

		if (!pag->pagf_init) {

			ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);

			ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));

			goto out_agbp_relse;

		}

	}
@@ -2533,11 +2532,10 @@ xfs_alloc_fix_freelist( 
	 */

	if (!agbp) {

		error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);

		if (error)

			goto out_no_agbp;

		if (!agbp) {

			ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);

			ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));

		if (error) {

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

			if (error == -EAGAIN)

				error = 0;

			goto out_no_agbp;

		}

	}
@@ -2768,11 +2766,10 @@ xfs_alloc_pagf_init( 
	xfs_buf_t		*bp;

	int			error;



	if ((error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp)))

		return error;

	if (bp)

	error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp);

	if (!error)

		xfs_trans_brelse(tp, bp);

	return 0;

	return error;

}



/*
@@ -2961,12 +2958,6 @@ xfs_read_agf( 
	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,

			XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),

			XFS_FSS_TO_BB(mp, 1), flags, bpp, &xfs_agf_buf_ops);

	/*

	 * Callers of xfs_read_agf() currently interpret a NULL bpp as EAGAIN

	 * and need to be converted to check for EAGAIN specifically.

	 */

	if (error == -EAGAIN)

		return 0;

	if (error)

		return error;
@@ -2992,14 +2983,15 @@ xfs_alloc_read_agf( 


	trace_xfs_alloc_read_agf(mp, agno);



	/* We don't support trylock when freeing. */

	ASSERT((flags & (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK)) !=

			(XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK));

	ASSERT(agno != NULLAGNUMBER);

	error = xfs_read_agf(mp, tp, agno,

			(flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,

			bpp);

	if (error)

		return error;

	if (!*bpp)

		return 0;

	ASSERT(!(*bpp)->b_error);



	agf = XFS_BUF_TO_AGF(*bpp);

fs/xfs/libxfs/xfs_bmap.c

+6 −5
Original line number Diff line number Diff line
@@ -3311,11 +3311,12 @@ xfs_bmap_longest_free_extent( 
	pag = xfs_perag_get(mp, ag);

	if (!pag->pagf_init) {

		error = xfs_alloc_pagf_init(mp, tp, ag, XFS_ALLOC_FLAG_TRYLOCK);

		if (error)

			goto out;



		if (!pag->pagf_init) {

		if (error) {

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

			if (error == -EAGAIN) {

				*notinit = 1;

				error = 0;

			}

			goto out;

		}

	}

fs/xfs/xfs_filestream.c

+5 −6
Original line number Diff line number Diff line
@@ -159,16 +159,15 @@ xfs_filestream_pick_ag( 


		if (!pag->pagf_init) {

			err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);

			if (err && !trylock) {

			if (err) {

				xfs_perag_put(pag);

				if (err != -EAGAIN)

					return err;

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

				continue;

			}

		}



		/* Might fail sometimes during the 1st pass with trylock set. */

		if (!pag->pagf_init)

			goto next_ag;



		/* Keep track of the AG with the most free blocks. */

		if (pag->pagf_freeblks > maxfree) {

			maxfree = pag->pagf_freeblks;