Commit 81a1e1c3 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Carlos Maiolino
Browse files

xfs: streamline xfs_filestream_pick_ag 



Directly return the error from xfs_bmap_longest_free_extent instead
of breaking from the loop and handling it there, and use a done
label to directly jump to the exist when we found a suitable perag
structure to reduce the indentation level and pag/max_pag check
complexity in the tail of the function.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarCarlos Maiolino <cem@kernel.org>
parent dc60992c

fs/xfs/xfs_filestream.c

+46 −50
Original line number Diff line number Diff line
@@ -67,23 +67,29 @@ xfs_filestream_pick_ag( 
	xfs_extlen_t		minfree, maxfree = 0;

	xfs_agnumber_t		agno;

	bool			first_pass = true;

	int			err;



	/* 2% of an AG's blocks must be free for it to be chosen. */

	minfree = mp->m_sb.sb_agblocks / 50;



restart:

	for_each_perag_wrap(mp, start_agno, agno, pag) {

		int		err;



		trace_xfs_filestream_scan(pag, pino);



		*longest = 0;

		err = xfs_bmap_longest_free_extent(pag, NULL, longest);

		if (err) {

			if (err != -EAGAIN)

				break;

			if (err == -EAGAIN) {

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

				err = 0;

				continue;

			}

			xfs_perag_rele(pag);

			if (max_pag)

				xfs_perag_rele(max_pag);

			return err;

		}



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

		if (pag->pagf_freeblks > maxfree) {
@@ -107,7 +113,9 @@ xfs_filestream_pick_ag( 
			     !(flags & XFS_PICK_USERDATA) ||

			     (flags & XFS_PICK_LOWSPACE))) {

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

				break;

				if (max_pag)

					xfs_perag_rele(max_pag);

				goto done;

			}

		}
@@ -115,18 +123,10 @@ xfs_filestream_pick_ag( 
		atomic_dec(&pag->pagf_fstrms);

	}



	if (err) {

		xfs_perag_rele(pag);

		if (max_pag)

			xfs_perag_rele(max_pag);

		return err;

	}



	if (!pag) {

	/*

		 * Allow a second pass to give xfs_bmap_longest_free_extent()

		 * another attempt at locking AGFs that it might have skipped

		 * over before we fail.

	 * Allow a second pass to give xfs_bmap_longest_free_extent() another

	 * attempt at locking AGFs that it might have skipped over before we

	 * fail.

	 */

	if (first_pass) {

		first_pass = false;
@@ -134,8 +134,8 @@ xfs_filestream_pick_ag( 
	}



	/*

		 * We must be low on data space, so run a final lowspace

		 * optimised selection pass if we haven't already.

	 * We must be low on data space, so run a final lowspace optimised

	 * selection pass if we haven't already.

	 */

	if (!(flags & XFS_PICK_LOWSPACE)) {

		flags |= XFS_PICK_LOWSPACE;
@@ -143,10 +143,9 @@ xfs_filestream_pick_ag( 
	}



	/*

		 * No unassociated AGs are available, so select the AG with the

		 * most free space, regardless of whether it's already in use by

		 * another filestream. It none suit, just use whatever AG we can

		 * grab.

	 * No unassociated AGs are available, so select the AG with the most

	 * free space, regardless of whether it's already in use by another

	 * filestream. It none suit, just use whatever AG we can grab.

	 */

	if (!max_pag) {

		for_each_perag_wrap(args->mp, 0, start_agno, pag) {
@@ -161,10 +160,7 @@ xfs_filestream_pick_ag( 


	pag = max_pag;

	atomic_inc(&pag->pagf_fstrms);

	} else if (max_pag) {

		xfs_perag_rele(max_pag);

	}



done:

	trace_xfs_filestream_pick(pag, pino);

	args->pag = pag;

	return 0;