From 7de3839d0ddba53272d35efe425248aa2a208cc2 Mon Sep 17 00:00:00 2001
From: Tor Egge <tegge@FreeBSD.org>
Date: Sun, 19 Mar 2006 21:43:36 +0000
Subject: Let snapshots make a copy of old contents for all buffers taking part
 in a cluster instead of just the first buffer.

Delay buf_start() calls until snapshots have a copy of old content.

PR:		kern/93942
---
 sys/kern/vfs_cluster.c   |  6 +-----
 sys/ufs/ffs/ffs_vfsops.c | 49 +++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 39 insertions(+), 16 deletions(-)

diff --git a/sys/kern/vfs_cluster.c b/sys/kern/vfs_cluster.c
index 326682933cda..fb64a6e69a2e 100644
--- a/sys/kern/vfs_cluster.c
+++ b/sys/kern/vfs_cluster.c
@@ -51,6 +51,7 @@ __FBSDID("$FreeBSD$");
 #include <vm/vm_object.h>
 #include <vm/vm_page.h>
 #include <sys/sysctl.h>
+int	softdep_wantrollbacks(struct buf *);
 
 #if defined(CLUSTERDEBUG)
 static int	rcluster= 0;
@@ -896,11 +897,6 @@ cluster_wbuild(vp, size, start_lbn, len)
 				bremfree(tbp);
 				tbp->b_flags &= ~B_DONE;
 			} /* end of code for non-first buffers only */
-			/* check for latent dependencies to be handled */
-			if ((LIST_FIRST(&tbp->b_dep)) != NULL) {
-				tbp->b_iocmd = BIO_WRITE;
-				buf_start(tbp);
-			}
 			/*
 			 * If the IO is via the VM then we do some
 			 * special VM hackery (yuck).  Since the buffer's
diff --git a/sys/ufs/ffs/ffs_vfsops.c b/sys/ufs/ffs/ffs_vfsops.c
index 2cc50181319e..fbc143c15d08 100644
--- a/sys/ufs/ffs/ffs_vfsops.c
+++ b/sys/ufs/ffs/ffs_vfsops.c
@@ -1758,27 +1758,54 @@ ffs_geom_strategy(struct bufobj *bo, struct buf *bp)
 {
 	struct vnode *vp;
 	int error;
+#ifdef SOFTUPDATES
+	struct buf *tbp;
+#endif
 
 	vp = bo->__bo_vnode;
 	if (bp->b_iocmd == BIO_WRITE) {
-#ifdef SOFTUPDATES
-		if (LIST_FIRST(&bp->b_dep) != NULL)
-			buf_start(bp);
-#endif
 		if ((bp->b_flags & B_VALIDSUSPWRT) == 0 &&
 		    bp->b_vp != NULL && bp->b_vp->v_mount != NULL &&
 		    (bp->b_vp->v_mount->mnt_kern_flag & MNTK_SUSPENDED) != 0)
 			panic("ffs_geom_strategy: bad I/O");
 		bp->b_flags &= ~B_VALIDSUSPWRT;
 		if ((vp->v_vflag & VV_COPYONWRITE) &&
-		    vp->v_rdev->si_snapdata != NULL &&
-		    (error = (ffs_copyonwrite)(vp, bp)) != 0 &&
-		    error != EOPNOTSUPP) {
-			bp->b_error = error;
-			bp->b_ioflags |= BIO_ERROR;
-			bufdone(bp);
-			return;
+		    vp->v_rdev->si_snapdata != NULL) {
+			if ((bp->b_flags & B_CLUSTER) != 0) {
+				TAILQ_FOREACH(tbp, &bp->b_cluster.cluster_head,
+					      b_cluster.cluster_entry) {
+					error = ffs_copyonwrite(vp, tbp);
+					if (error != 0 &&
+					    error != EOPNOTSUPP) {
+						bp->b_error = error;
+						bp->b_ioflags |= BIO_ERROR;
+						bufdone(bp);
+						return;
+					}
+				}
+			} else {
+				error = ffs_copyonwrite(vp, bp);
+				if (error != 0 && error != EOPNOTSUPP) {
+					bp->b_error = error;
+					bp->b_ioflags |= BIO_ERROR;
+					bufdone(bp);
+					return;
+				}
+			}
 		}
+#ifdef SOFTUPDATES
+		if ((bp->b_flags & B_CLUSTER) != 0) {
+			TAILQ_FOREACH(tbp, &bp->b_cluster.cluster_head,
+				      b_cluster.cluster_entry) {
+				if (LIST_FIRST(&tbp->b_dep) != NULL)
+					buf_start(tbp);
+			}
+		} else {
+			if (LIST_FIRST(&bp->b_dep) != NULL)
+				buf_start(bp);
+		}
+
+#endif
 	}
 	g_vfs_strategy(bo, bp);
 }
-- 
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