From 9316467d05e64eedf1f34d8f0053eeebc5c8c124 Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Tue, 20 Jan 2009 11:27:45 +0000
Subject: [PATCH] FFS puts the extended attributes blocks at the negative
 blocks for the vnode, from -1 down. When vinvalbuf(vp, V_ALT) is done for the
 vnode, it incorrectly does vm_object_page_remove(0, 0), removing all pages
 from the underlying vm object, not only the pages that back the extended
 attributes data.

Change vinvalbuf() to not remove any pages from the object when
V_NORMAL or V_ALT are specified. Instead, the only in-tree caller
in ffs_inode.c:ffs_truncate() that specifies V_ALT explicitely
removes the corresponding page range. The V_NORMAL caller
does vnode_pager_setsize(vp, 0) immediately after the call to
vinvalbuf(V_NORMAL) already.

Reported by:	csjp
Reviewed by:	ups
MFC after:	3 weeks
---
 sys/kern/vfs_subr.c     | 2 +-
 sys/ufs/ffs/ffs_inode.c | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index eb0269326808..1e4bf902d075 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -1156,7 +1156,7 @@ bufobj_invalbuf(struct bufobj *bo, int flags, int slpflag, int slptimeo)
 	/*
 	 * Destroy the copy in the VM cache, too.
 	 */
-	if (bo->bo_object != NULL) {
+	if (bo->bo_object != NULL && (flags & (V_ALT | V_NORMAL)) == 0) {
 		VM_OBJECT_LOCK(bo->bo_object);
 		vm_object_page_remove(bo->bo_object, 0, 0,
 			(flags & V_SAVE) ? TRUE : FALSE);
diff --git a/sys/ufs/ffs/ffs_inode.c b/sys/ufs/ffs/ffs_inode.c
index fa679ef1f812..2be220e36a54 100644
--- a/sys/ufs/ffs/ffs_inode.c
+++ b/sys/ufs/ffs/ffs_inode.c
@@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$");
 
 #include <vm/vm.h>
 #include <vm/vm_extern.h>
+#include <vm/vm_object.h>
 
 #include <ufs/ufs/extattr.h>
 #include <ufs/ufs/quota.h>
@@ -151,6 +152,7 @@ ffs_truncate(vp, length, flags, cred, td)
 	struct fs *fs;
 	struct buf *bp;
 	struct ufsmount *ump;
+	vm_object_t object;
 	int needextclean, softdepslowdown, extblocks;
 	int offset, size, level, nblocks;
 	int i, error, allerror;
@@ -205,6 +207,13 @@ ffs_truncate(vp, length, flags, cred, td)
 			(void) chkdq(ip, -extblocks, NOCRED, 0);
 #endif
 			vinvalbuf(vp, V_ALT, 0, 0);
+			if ((object = vp->v_object) != NULL) {
+				VM_OBJECT_LOCK(object);
+				vm_object_page_remove(object,
+				    OFF_TO_IDX(lblktosize(fs, -extblocks)), 0,
+				    FALSE);
+				VM_OBJECT_UNLOCK(object);
+			}
 			ip->i_din2->di_extsize = 0;
 			for (i = 0; i < NXADDR; i++) {
 				oldblks[i] = ip->i_din2->di_extb[i];