Commit 5113f8ec authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: clean up weird while loop in xfs_alloc_ag_vextent_near 



Refactor the weird while loop out of existence.

Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent f7559793

fs/xfs/libxfs/xfs_alloc.c

+65 −52
Original line number Diff line number Diff line
@@ -1464,6 +1464,64 @@ xfs_alloc_ag_vextent_locality( 
	return 0;

}



/* Check the last block of the cnt btree for allocations. */

static int

xfs_alloc_ag_vextent_lastblock(

	struct xfs_alloc_arg	*args,

	struct xfs_alloc_cur	*acur,

	xfs_agblock_t		*bno,

	xfs_extlen_t		*len,

	bool			*allocated)

{

	int			error;

	int			i;



#ifdef DEBUG

	/* Randomly don't execute the first algorithm. */

	if (prandom_u32() & 1)

		return 0;

#endif



	/*

	 * Start from the entry that lookup found, sequence through all larger

	 * free blocks.  If we're actually pointing at a record smaller than

	 * maxlen, go to the start of this block, and skip all those smaller

	 * than minlen.

	 */

	if (len || args->alignment > 1) {

		acur->cnt->bc_ptrs[0] = 1;

		do {

			error = xfs_alloc_get_rec(acur->cnt, bno, len, &i);

			if (error)

				return error;

			XFS_WANT_CORRUPTED_RETURN(args->mp, i == 1);

			if (*len >= args->minlen)

				break;

			error = xfs_btree_increment(acur->cnt, 0, &i);

			if (error)

				return error;

		} while (i);

		ASSERT(*len >= args->minlen);

		if (!i)

			return 0;

	}



	error = xfs_alloc_walk_iter(args, acur, acur->cnt, true, false, -1, &i);

	if (error)

		return error;



	/*

	 * It didn't work.  We COULD be in a case where there's a good record

	 * somewhere, so try again.

	 */

	if (acur->len == 0)

		return 0;



	trace_xfs_alloc_near_first(args);

	*allocated = true;

	return 0;

}



/*

 * Allocate a variable extent near bno in the allocation group agno.

 * Extent's length (returned in len) will be between minlen and maxlen,
@@ -1479,14 +1537,6 @@ xfs_alloc_ag_vextent_near( 
	int			i;		/* result code, temporary */

	xfs_agblock_t		bno;

	xfs_extlen_t		len;

#ifdef DEBUG

	/*

	 * Randomly don't execute the first algorithm.

	 */

	int		dofirst;	/* set to do first algorithm */



	dofirst = prandom_u32() & 1;

#endif



	/* handle uninitialized agbno range so caller doesn't have to */

	if (!args->min_agbno && !args->max_agbno)
@@ -1529,53 +1579,16 @@ xfs_alloc_ag_vextent_near( 
	 * near the right edge of the tree.  If it's in the last btree leaf

	 * block, then we just examine all the entries in that block

	 * that are big enough, and pick the best one.

	 * This is written as a while loop so we can break out of it,

	 * but we never loop back to the top.

	 */

	while (xfs_btree_islastblock(acur.cnt, 0)) {

#ifdef DEBUG

		if (dofirst)

			break;

#endif

		/*

		 * Start from the entry that lookup found, sequence through

		 * all larger free blocks.  If we're actually pointing at a

		 * record smaller than maxlen, go to the start of this block,

		 * and skip all those smaller than minlen.

	 */

		if (len || args->alignment > 1) {

			acur.cnt->bc_ptrs[0] = 1;

			do {

				error = xfs_alloc_get_rec(acur.cnt, &bno, &len,

						&i);

				if (error)

					goto out;

				XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, out);

				if (len >= args->minlen)

					break;

				error = xfs_btree_increment(acur.cnt, 0, &i);

				if (error)

					goto out;

			} while (i);

			ASSERT(len >= args->minlen);

			if (!i)

				break;

		}

	if (xfs_btree_islastblock(acur.cnt, 0)) {

		bool		allocated = false;



		error = xfs_alloc_walk_iter(args, &acur, acur.cnt, true, false,

					    -1, &i);

		error = xfs_alloc_ag_vextent_lastblock(args, &acur, &bno, &len,

				&allocated);

		if (error)

			goto out;



		/*

		 * It didn't work.  We COULD be in a case where

		 * there's a good record somewhere, so try again.

		 */

		if (acur.len == 0)

			break;



		trace_xfs_alloc_near_first(args);

		goto alloc;

		if (allocated)

			goto alloc_finish;

	}



	/*
@@ -1601,7 +1614,7 @@ xfs_alloc_ag_vextent_near( 
		goto out;

	}



alloc:

alloc_finish:

	/* fix up btrees on a successful allocation */

	error = xfs_alloc_cur_finish(args, &acur);