1 files changed, 38 insertions, 28 deletions

diff --git a/sys/kern/vfs_cluster.c b/sys/kern/vfs_cluster.c
index c34fbc3..e01d24f 100644
--- a/sys/kern/vfs_cluster.c
+++ b/sys/kern/vfs_cluster.c
@@ -30,7 +30,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	@(#)vfs_cluster.c	8.7 (Berkeley) 2/13/94
+ *	@(#)vfs_cluster.c	8.10 (Berkeley) 3/28/95
  */
 
 #include <sys/param.h>
@@ -43,16 +43,6 @@
 #include <sys/resourcevar.h>
 #include <libkern/libkern.h>
 
-#ifdef DEBUG
-#include <vm/vm.h>
-#include <sys/sysctl.h>
-int doreallocblks = 1;
-struct ctldebug debug13 = { "doreallocblks", &doreallocblks };
-#else
-/* XXX for cluster_write */
-#define doreallocblks 1
-#endif
-
 /*
  * Local declarations
  */
@@ -135,7 +125,7 @@ cluster_read(vp, filesize, lblkno, size, cred, bpp)
 		trace(TR_BREADHIT, pack(vp, size), lblkno);
 		flags |= B_ASYNC;
 		ioblkno = lblkno + (vp->v_ralen ? vp->v_ralen : 1);
-		alreadyincore = (int)incore(vp, ioblkno);
+		alreadyincore = incore(vp, ioblkno) != NULL;
 		bp = NULL;
 	} else {
 		/* Block wasn't in cache, case 3, 4, 5. */
@@ -202,10 +192,12 @@ cluster_read(vp, filesize, lblkno, size, cred, bpp)
 			     ioblkno, NULL, &blkno, &num_ra)) || blkno == -1)
 				goto skip_readahead;
 			/*
-			 * Adjust readahead as above
+			 * Adjust readahead as above.
+			 * Don't check alreadyincore, we know it is 0 from
+			 * the previous conditional.
 			 */
 			if (num_ra) {
-				if (!alreadyincore && ioblkno <= vp->v_maxra)
+				if (ioblkno <= vp->v_maxra)
 					vp->v_ralen = max(vp->v_ralen >> 1, 1);
 				else if (num_ra > vp->v_ralen &&
 					 lblkno != vp->v_lastr)
@@ -318,17 +310,12 @@ cluster_rbuild(vp, filesize, bp, lbn, blkno, size, run, flags)
 
 	inc = btodb(size);
 	for (bn = blkno + inc, i = 1; i <= run; ++i, bn += inc) {
-		if (incore(vp, lbn + i)) {
-			if (i == 1) {
-				bp->b_saveaddr = b_save->bs_saveaddr;
-				bp->b_flags &= ~B_CALL;
-				bp->b_iodone = NULL;
-				allocbuf(bp, size);
-				free(b_save, M_SEGMENT);
-			} else
-				allocbuf(bp, size * i);
+		/*
+		 * A component of the cluster is already in core,
+		 * terminate the cluster early.
+		 */
+		if (incore(vp, lbn + i))
 			break;
-		}
 		tbp = getblk(vp, lbn + i, 0, 0, 0);
 		/*
 		 * getblk may return some memory in the buffer if there were
@@ -341,8 +328,18 @@ cluster_rbuild(vp, filesize, bp, lbn, blkno, size, run, flags)
 		if (tbp->b_bufsize != 0) {
 			caddr_t bdata = (char *)tbp->b_data;
 
-			if (tbp->b_bufsize + size > MAXBSIZE)
-				panic("cluster_rbuild: too much memory");
+			/*
+			 * No room in the buffer to add another page,
+			 * terminate the cluster early.
+			 */
+			if (tbp->b_bufsize + size > MAXBSIZE) {
+#ifdef DIAGNOSTIC
+				if (tbp->b_bufsize != MAXBSIZE)
+					panic("cluster_rbuild: too much memory");
+#endif
+				brelse(tbp);
+				break;
+			}
 			if (tbp->b_bufsize > size) {
 				/*
 				 * XXX if the source and destination regions
@@ -364,6 +361,20 @@ cluster_rbuild(vp, filesize, bp, lbn, blkno, size, run, flags)
 		++b_save->bs_nchildren;
 		b_save->bs_children[i - 1] = tbp;
 	}
+	/*
+	 * The cluster may have been terminated early, adjust the cluster
+	 * buffer size accordingly.  If no cluster could be formed,
+	 * deallocate the cluster save info.
+	 */
+	if (i <= run) {
+		if (i == 1) {
+			bp->b_saveaddr = b_save->bs_saveaddr;
+			bp->b_flags &= ~B_CALL;
+			bp->b_iodone = NULL;
+			free(b_save, M_SEGMENT);
+		}
+		allocbuf(bp, size * i);
+	}
 	return(bp);
 }
 
@@ -498,8 +509,7 @@ cluster_write(bp, filesize)
 			 * Otherwise try reallocating to make it sequential.
 			 */
 			cursize = vp->v_lastw - vp->v_cstart + 1;
-			if (!doreallocblks ||
-			    (lbn + 1) * bp->b_bcount != filesize ||
+			if ((lbn + 1) * bp->b_bcount != filesize ||
 			    lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) {
 				cluster_wbuild(vp, NULL, bp->b_bcount,
 				    vp->v_cstart, cursize, lbn);