diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 0965f2747d78..526429d02f45 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -981,7 +981,7 @@ bdwrite(struct buf * bp)
 	 */
 	vp = bp->b_vp;
 	VI_LOCK(vp);
-	if (td->td_proc->p_flag & P_COWINPROGRESS) {
+	if (td->td_pflags & TDP_COWINPROGRESS) {
 		recursiveflushes++;
 	} else if (vp != NULL && vp->v_dirtybufcnt > dirtybufthresh + 10) {
 		VI_UNLOCK(vp);
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 2ff8a0bc6b51..dbea7e954ab1 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -358,6 +358,7 @@ struct thread {
 #define	TDP_INKTR	0x0002 /* Thread is currently in KTR code. */
 #define	TDP_INKTRACE	0x0004 /* Thread is currently in KTRACE code. */
 #define	TDP_UPCALLING	0x0008 /* This thread is doing an upcall. */
+#define	TDP_COWINPROGRESS 0x0010 /* Snapshot copy-on-write in progress. */
 
 #define	TDI_SUSPENDED	0x0001	/* On suspension queue. */
 #define	TDI_SLEEPING	0x0002	/* Actually asleep! (tricky). */
@@ -641,8 +642,6 @@ struct proc {
 					/* (not to user) */
 #define	P_PROTECTED	0x100000 /* Do not kill on memory overcommit. */
 #define	P_SIGEVENT	0x200000 /* Process pending signals changed */
-/* Should be moved to machine-dependent areas. */
-#define	P_COWINPROGRESS	0x400000 /* Snapshot copy-on-write in progress. */
 
 #define	P_JAILED	0x1000000 /* Process is in jail. */
 #define	P_ALTSTACK	0x2000000 /* Have alternate signal stack. */
diff --git a/sys/ufs/ffs/ffs_snapshot.c b/sys/ufs/ffs/ffs_snapshot.c
index b3b54d1dcd49..cd50ece13e9d 100644
--- a/sys/ufs/ffs/ffs_snapshot.c
+++ b/sys/ufs/ffs/ffs_snapshot.c
@@ -822,10 +822,10 @@ expunge_ufs1(snapvp, cancelip, fs, acctfunc, expungetype)
 	if (lbn < NDADDR) {
 		blkno = VTOI(snapvp)->i_din1->di_db[lbn];
 	} else {
-		td->td_proc->p_flag |= P_COWINPROGRESS;
+		td->td_pflags |= TDP_COWINPROGRESS;
 		error = UFS_BALLOC(snapvp, lblktosize(fs, (off_t)lbn),
 		   fs->fs_bsize, KERNCRED, BA_METAONLY, &bp);
-		td->td_proc->p_flag &= ~P_COWINPROGRESS;
+		td->td_pflags &= ~TDP_COWINPROGRESS;
 		if (error)
 			return (error);
 		indiroff = (lbn - NDADDR) % NINDIR(fs);
@@ -1102,10 +1102,10 @@ expunge_ufs2(snapvp, cancelip, fs, acctfunc, expungetype)
 	if (lbn < NDADDR) {
 		blkno = VTOI(snapvp)->i_din2->di_db[lbn];
 	} else {
-		td->td_proc->p_flag |= P_COWINPROGRESS;
+		td->td_pflags |= TDP_COWINPROGRESS;
 		error = UFS_BALLOC(snapvp, lblktosize(fs, (off_t)lbn),
 		   fs->fs_bsize, KERNCRED, BA_METAONLY, &bp);
-		td->td_proc->p_flag &= ~P_COWINPROGRESS;
+		td->td_pflags &= ~TDP_COWINPROGRESS;
 		if (error)
 			return (error);
 		indiroff = (lbn - NDADDR) % NINDIR(fs);
@@ -1552,10 +1552,10 @@ ffs_snapblkfree(fs, devvp, bno, size, inum)
 			      VI_MTX(devvp), td) != 0)
 				goto retry;
 			snapshot_locked = 1;
-			td->td_proc->p_flag |= P_COWINPROGRESS;
+			td->td_pflags |= TDP_COWINPROGRESS;
 			error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
 			    fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
-			td->td_proc->p_flag &= ~P_COWINPROGRESS;
+			td->td_pflags &= ~TDP_COWINPROGRESS;
 			if (error)
 				break;
 			indiroff = (lbn - NDADDR) % NINDIR(fs);
@@ -1659,10 +1659,10 @@ ffs_snapblkfree(fs, devvp, bno, size, inum)
 		 * allocation will never require any additional allocations for
 		 * the snapshot inode.
 		 */
-		td->td_proc->p_flag |= P_COWINPROGRESS;
+		td->td_pflags |= TDP_COWINPROGRESS;
 		error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
 		    fs->fs_bsize, KERNCRED, 0, &cbp);
-		td->td_proc->p_flag &= ~P_COWINPROGRESS;
+		td->td_pflags &= ~TDP_COWINPROGRESS;
 		if (error)
 			break;
 #ifdef DEBUG
@@ -1930,7 +1930,7 @@ ffs_copyonwrite(devvp, bp)
 	ufs2_daddr_t lbn, blkno, *snapblklist;
 	int lower, upper, mid, indiroff, snapshot_locked = 0, error = 0;
 
-	if (td->td_proc->p_flag & P_COWINPROGRESS)
+	if (td->td_pflags & TDP_COWINPROGRESS)
 		panic("ffs_copyonwrite: recursive call");
 	/*
 	 * First check to see if it is in the preallocated list.
@@ -1988,10 +1988,10 @@ ffs_copyonwrite(devvp, bp)
 				goto retry;
 			}
 			snapshot_locked = 1;
-			td->td_proc->p_flag |= P_COWINPROGRESS;
+			td->td_pflags |= TDP_COWINPROGRESS;
 			error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
 			   fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
-			td->td_proc->p_flag &= ~P_COWINPROGRESS;
+			td->td_pflags &= ~TDP_COWINPROGRESS;
 			if (error)
 				break;
 			indiroff = (lbn - NDADDR) % NINDIR(fs);
@@ -2025,10 +2025,10 @@ ffs_copyonwrite(devvp, bp)
 			goto retry;
 		}
 		snapshot_locked = 1;
-		td->td_proc->p_flag |= P_COWINPROGRESS;
+		td->td_pflags |= TDP_COWINPROGRESS;
 		error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
 		    fs->fs_bsize, KERNCRED, 0, &cbp);
-		td->td_proc->p_flag &= ~P_COWINPROGRESS;
+		td->td_pflags &= ~TDP_COWINPROGRESS;
 		if (error)
 			break;
 #ifdef DEBUG
diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c
index 768a6b536ea8..3ebe427ffdf9 100644
--- a/sys/ufs/ffs/ffs_softdep.c
+++ b/sys/ufs/ffs/ffs_softdep.c
@@ -688,7 +688,7 @@ process_worklist_item(matchmnt, flags)
 	 * copy-on-write, then it is not safe to write as we may
 	 * recurse into the copy-on-write routine.
 	 */
-	if (curthread->td_proc->p_flag & P_COWINPROGRESS)
+	if (curthread->td_pflags & TDP_COWINPROGRESS)
 		return (-1);
 	ACQUIRE_LOCK(&lk);
 	/*
@@ -5479,7 +5479,7 @@ softdep_request_cleanup(fs, vp)
 	 * copy-on-write, then it is not safe to update the vnode
 	 * as we may recurse into the copy-on-write routine.
 	 */
-	if ((curthread->td_proc->p_flag & P_COWINPROGRESS) == 0 &&
+	if (!(curthread->td_pflags & TDP_COWINPROGRESS) &&
 	    UFS_UPDATE(vp, 1) != 0)
 		return (0);
 	while (fs->fs_pendingblocks > 0 && fs->fs_cstotal.cs_nbfree <= needed) {