2 files changed, 18 insertions, 1 deletions

diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 8017e19b2722..47059032cb48 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -604,6 +604,10 @@ breadn(struct vnode * vp, daddr_t blkno, int size,
  * or in biodone() since the I/O is synchronous.  We put it
  * here.
  */
+
+int dobkgrdwrite = 1;
+SYSCTL_INT(_debug, OID_AUTO, dobkgrdwrite, CTLFLAG_RW, &dobkgrdwrite, 0, "");
+
 int
 bwrite(struct buf * bp)
 {
@@ -648,7 +652,7 @@ bwrite(struct buf * bp)
 	 * This optimization eats a lot of memory.  If we have a page
 	 * or buffer shortfall we can't do it.
 	 */
-	if ((bp->b_xflags & BX_BKGRDWRITE) && 
+	if (dobkgrdwrite && (bp->b_xflags & BX_BKGRDWRITE) && 
 	    (bp->b_flags & B_ASYNC) &&
 	    !vm_page_count_severe() &&
 	    !buf_dirty_count_severe()) {
diff --git a/sys/ufs/ffs/ffs_vfsops.c b/sys/ufs/ffs/ffs_vfsops.c
index 80bed87fe38a..aa2960dd02f5 100644
--- a/sys/ufs/ffs/ffs_vfsops.c
+++ b/sys/ufs/ffs/ffs_vfsops.c
@@ -499,6 +499,10 @@ loop:
 	return (0);
 }
 
+#include <sys/sysctl.h>
+int bigcgs = 0;
+SYSCTL_INT(_debug, OID_AUTO, bigcgs, CTLFLAG_RW, &bigcgs, 0, "");
+
 /*
  * Common code for mount and mountroot
  */
@@ -701,6 +705,11 @@ ffs_mountfs(devvp, mp, p, malloctype)
 	maxfilesize = (u_int64_t)0x40000000 * fs->fs_bsize - 1;	/* XXX */
 	if (fs->fs_maxfilesize > maxfilesize)			/* XXX */
 		fs->fs_maxfilesize = maxfilesize;		/* XXX */
+	if (bigcgs) {
+		if (fs->fs_sparecon[0] <= 0)
+			fs->fs_sparecon[0] = fs->fs_cgsize;
+		fs->fs_cgsize = fs->fs_bsize;
+	}
 	if (ronly == 0) {
 		if ((fs->fs_flags & FS_DOSOFTDEP) &&
 		    (error = softdep_mount(devvp, mp, fs, cred)) != 0) {
@@ -806,6 +815,10 @@ ffs_unmount(mp, mntflags, p)
 			return (error);
 	}
 	fs = ump->um_fs;
+	if (bigcgs) {
+		fs->fs_cgsize = fs->fs_sparecon[0];
+		fs->fs_sparecon[0] = 0;
+	}
 	if (fs->fs_ronly == 0) {
 		fs->fs_clean = fs->fs_flags & (FS_UNCLEAN|FS_NEEDSFSCK) ? 0 : 1;
 		error = ffs_sbupdate(ump, MNT_WAIT);