From: Francois Tigeot <ftigeot@wolfpond.org>
Date: Thu, 22 Mar 2012 16:51:47 +0000 (+0100)
Subject: VFS accounting: handle file truncation on open(2)
X-Git-Tag: v3.4.0rc~1160^2
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/18cd8808a42f4ca63dec5ead58586c05a05a909b

VFS accounting: handle file truncation on open(2)

* Files succesfully opened with O_TRUNC are truncated to zero length.
  This case was not previously handled, leading to a growing drift
  between VFS counters and reality.

* Fix a buildworld issue caused by the last VFS accounting commit
---

diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index 27ac2b177d..0bd1afff26 100644
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -104,6 +104,8 @@ vn_open(struct nlookupdata *nd, struct file *fp, int fmode, int cmode)
 	struct vattr *vap = &vat;
 	int error;
 	u_int flags;
+	uint64_t osize;
+	struct mount *mp;
 
 	/*
 	 * Certain combinations are illegal
@@ -233,11 +235,17 @@ again:
 	if (fmode & O_TRUNC) {
 		vn_unlock(vp);				/* XXX */
 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);	/* XXX */
+		osize = vp->v_filesize;
 		VATTR_NULL(vap);
 		vap->va_size = 0;
 		error = VOP_SETATTR(vp, vap, cred);
 		if (error)
 			goto bad;
+		error = VOP_GETATTR(vp, vap);
+		if (error)
+			goto bad;
+		mp = vq_vptomp(vp);
+		VFS_ACCOUNT(mp, vap->va_uid, vap->va_gid, -osize);
 	}
 
 	/*
diff --git a/sys/sys/vfs_quota.h b/sys/sys/vfs_quota.h
index d6c438a166..9329109acf 100644
--- a/sys/sys/vfs_quota.h
+++ b/sys/sys/vfs_quota.h
@@ -34,6 +34,7 @@
 #define _SYS_VFSQUOTA_H_
 
 #include <sys/mount.h>
+#include <sys/vnode.h>
 #include <libprop/proplib.h>
 
 extern void vq_init(struct mount*);
@@ -43,7 +44,9 @@ int vquotactl(const char *path, struct plistref *pref);
 
 extern int vfs_accounting_enabled;
 
+#if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
 struct mount* vq_vptomp(struct vnode*);
+#endif
 
 #endif