Ocfs2/move_extents: helper to calculate the defraging length in one run. (ee16cc03) · Commits · 戴 / test

The helper is to calculate the defrag length in one run according to a threshold, it will proceed doing defragmentation until the threshold was meet, and skip a LARGE extent if any. Signed-off-by:

Tristan Ye <tristan.ye@oracle.com>

fs/ocfs2/move_extents.c

+30 −0

Original line number	Diff line number	Diff line
		@@ -797,3 +797,33 @@ out:

		return ret;
		}

		/*
		* Helper to calculate the defraging length in one run according to threshold.
		*/
		static void ocfs2_calc_extent_defrag_len(u32 alloc_size, u32 len_defraged,
		u32 threshold, int *skip)
		{
		if ((alloc_size + len_defraged) < threshold) {
		/*
		* proceed defragmentation until we meet the thresh
		*/
		len_defraged += alloc_size;
		} else if (*len_defraged == 0) {
		/*
		* XXX: skip a large extent.
		*/
		*skip = 1;
		} else {
		/*
		* split this extent to coalesce with former pieces as
		* to reach the threshold.
		*
		* we're done here with one cycle of defragmentation
		* in a size of 'thresh', resetting 'len_defraged'
		* forces a new defragmentation.
		*/
		alloc_size = threshold - len_defraged;
		*len_defraged = 0;
		}
		}

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