1 files changed, 104 insertions, 0 deletions
diff --git a/sys/fs/ext2fs/ext2_subr.c b/sys/fs/ext2fs/ext2_subr.c
index 70ade83..b8d59bc 100644
--- a/sys/fs/ext2fs/ext2_subr.c
+++ b/sys/fs/ext2fs/ext2_subr.c
@@ -120,3 +120,107 @@ ext2_checkoverlap(bp, ip)
 	}
 }
 #endif /* KDB */
+
+/*
+ * Update the cluster map because of an allocation of free like ffs.
+ *
+ * Cnt == 1 means free; cnt == -1 means allocating.
+ */
+void
+ext2_clusteracct(struct m_ext2fs *fs, char *bbp, int cg, daddr_t bno, int cnt)
+{
+	int32_t *sump = fs->e2fs_clustersum[cg].cs_sum;
+	int32_t *lp;
+	int back, bit, end, forw, i, loc, start;
+
+	/* Initialize the cluster summary array. */
+	if (fs->e2fs_clustersum[cg].cs_init == 0) {
+		int run = 0;
+		bit = 1;
+		loc = 0;
+
+		for (i = 0; i < fs->e2fs->e2fs_fpg; i++) {
+			if ((bbp[loc] & bit) == 0)
+				run++;
+			else if (run != 0) {
+				if (run > fs->e2fs_contigsumsize)
+					run = fs->e2fs_contigsumsize;
+				sump[run]++;
+				run = 0;
+			}
+			if ((i & (NBBY - 1)) != (NBBY - 1))
+				bit <<= 1;
+			else {
+				loc++;
+				bit = 1;
+			}
+		}
+		if (run != 0) {
+			if (run > fs->e2fs_contigsumsize)
+				run = fs->e2fs_contigsumsize;
+			sump[run]++;
+		}
+		fs->e2fs_clustersum[cg].cs_init = 1;
+	}
+
+	if (fs->e2fs_contigsumsize <= 0)
+		return;
+
+	/* Find the size of the cluster going forward. */
+	start = bno + 1;
+	end = start + fs->e2fs_contigsumsize;
+	if (end > fs->e2fs->e2fs_fpg)
+		end = fs->e2fs->e2fs_fpg;
+	loc = start / NBBY;
+	bit = 1 << (start % NBBY);
+	for (i = start; i < end; i++) {
+		if ((bbp[loc] & bit) != 0)
+			break;
+		if ((i & (NBBY - 1)) != (NBBY - 1))
+			bit <<= 1;
+		else {
+			loc++;
+			bit = 1;
+		}
+	}
+	forw = i - start;
+
+	/* Find the size of the cluster going backward. */
+	start = bno - 1;
+	end = start - fs->e2fs_contigsumsize;
+	if (end < 0)
+		end = -1;
+	loc = start / NBBY;
+	bit = 1 << (start % NBBY);
+	for (i = start; i > end; i--) {
+		if ((bbp[loc] & bit) != 0)
+			break;
+		if ((i & (NBBY - 1)) != 0)
+			bit >>= 1;
+		else {
+			loc--;
+			bit = 1 << (NBBY - 1);
+		}
+	}
+	back = start - i;
+
+	/*
+	 * Account for old cluster and the possibly new forward and
+	 * back clusters.
+	 */
+	i = back + forw + 1;
+	if (i > fs->e2fs_contigsumsize)
+		i = fs->e2fs_contigsumsize;
+	sump[i] += cnt;
+	if (back > 0)
+		sump[back] -= cnt;
+	if (forw > 0)
+		sump[forw] -= cnt;
+
+	/* Update cluster summary information. */
+	lp = &sump[fs->e2fs_contigsumsize];
+	for (i = fs->e2fs_contigsumsize; i > 0; i--)
+		if (*lp-- > 0)
+			break;
+	fs->e2fs_maxcluster[cg] = i;
+}