Commit fd048a1b authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Darrick J. Wong
Browse files

xfs: rework the rtalloc fallback handling 



xfs_rtallocate currently has two fallbacks, when an allocation fails:

 1) drop the requested extent size alignment, if any, and retry
 2) ignore the locality hint

Oddly enough it does those in order, as trying a different location
is more in line with what the user asked for, and does it in a very
unstructured way.

Lift the fallback to try to allocate without the locality hint into
xfs_rtallocate to both perform them in a more sensible order and to
clean up the code.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent a9f646af

fs/xfs/xfs_rtalloc.c

+34 −35
Original line number Diff line number Diff line
@@ -1271,6 +1271,8 @@ xfs_rtallocate( 
	xfs_rtxlen_t		maxlen,

	xfs_rtxlen_t		prod,

	bool			wasdel,

	bool			initial_user_data,

	bool			*rtlocked,

	xfs_rtblock_t		*bno,

	xfs_extlen_t		*blen)

{
@@ -1280,12 +1282,38 @@ xfs_rtallocate( 
	};

	xfs_rtxnum_t		rtx;

	xfs_rtxlen_t		len = 0;

	int			error;

	int			error = 0;



	/*

	 * Lock out modifications to both the RT bitmap and summary inodes.

	 */

	if (!*rtlocked) {

		xfs_rtbitmap_lock(args.mp);

		xfs_rtbitmap_trans_join(tp);

		*rtlocked = true;

	}



	/*

	 * For an allocation to an empty file at offset 0, pick an extent that

	 * will space things out in the rt area.

	 */

	if (!start && initial_user_data)

		start = xfs_rtpick_extent(args.mp, tp, maxlen);



	if (start) {

		error = xfs_rtallocate_extent_near(&args, start, minlen, maxlen,

				&len, prod, &rtx);

	} else {

		/*

		 * If we can't allocate near a specific rt extent, try again

		 * without locality criteria.

		 */

		if (error == -ENOSPC) {

			xfs_rtbuf_cache_relse(&args);

			error = 0;

		}

	}



	if (!error) {

		error = xfs_rtallocate_extent_size(&args, minlen, maxlen, &len,

				prod, &rtx);

	}
@@ -1314,7 +1342,7 @@ xfs_bmap_rtalloc( 
{

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

	xfs_fileoff_t		orig_offset = ap->offset;

	xfs_rtxnum_t		start;	   /* allocation hint rtextent no */

	xfs_rtxnum_t		start = 0;   /* allocation hint rtextent no */

	xfs_rtxlen_t		prod = 0;  /* product factor for allocators */

	xfs_extlen_t		mod = 0;   /* product factor for allocators */

	xfs_rtxlen_t		ralen = 0; /* realtime allocation length */
@@ -1323,7 +1351,6 @@ xfs_bmap_rtalloc( 
	xfs_extlen_t		minlen = mp->m_sb.sb_rextsize;

	xfs_rtxlen_t		raminlen;

	bool			rtlocked = false;

	bool			ignore_locality = false;

	int			error;



	align = xfs_get_extsz_hint(ap->ip);
@@ -1361,28 +1388,8 @@ xfs_bmap_rtalloc( 
	ASSERT(raminlen > 0);

	ASSERT(raminlen <= ralen);



	/*

	 * Lock out modifications to both the RT bitmap and summary inodes

	 */

	if (!rtlocked) {

		xfs_rtbitmap_lock(mp);

		xfs_rtbitmap_trans_join(ap->tp);

		rtlocked = true;

	}



	if (ignore_locality) {

		start = 0;

	} else if (xfs_bmap_adjacent(ap)) {

	if (xfs_bmap_adjacent(ap))

		start = xfs_rtb_to_rtx(mp, ap->blkno);

	} else if (ap->datatype & XFS_ALLOC_INITIAL_USER_DATA) {

		/*

		 * If it's an allocation to an empty file at offset 0, pick an

		 * extent that will space things out in the rt area.

		 */

		start = xfs_rtpick_extent(mp, ap->tp, ralen);

	} else {

		start = 0;

	}



	/*

	 * Only bother calculating a real prod factor if offset & length are
@@ -1398,6 +1405,7 @@ xfs_bmap_rtalloc( 
	}



	error = xfs_rtallocate(ap->tp, start, raminlen, ralen, prod, ap->wasdel,

			ap->datatype & XFS_ALLOC_INITIAL_USER_DATA, &rtlocked,

			&ap->blkno, &ap->length);

	if (error == -ENOSPC) {

		if (align > mp->m_sb.sb_rextsize) {
@@ -1414,15 +1422,6 @@ xfs_bmap_rtalloc( 
			goto retry;

		}



		if (!ignore_locality && start != 0) {

			/*

			 * If we can't allocate near a specific rt extent, try

			 * again without locality criteria.

			 */

			ignore_locality = true;

			goto retry;

		}



		ap->blkno = NULLFSBLOCK;

		ap->length = 0;

		return 0;