xfs: clean up weird while loop in xfs_alloc_ag_vextent_near (5113f8ec) · Commits · 戴 / test

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 @@ restart:
		* 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 @@ restart:
		goto out;
		}

		alloc:
		alloc_finish:
		/* fix up btrees on a successful allocation */
		error = xfs_alloc_cur_finish(args, &acur);

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