OS-6275 lx pipe buffer is too small

Reviewed by: Patrick Mooney <patrick.mooney@joyent.com>
Approved by: Jason King <jason.king@joyent.com>

usr/src/uts/common/brand/lx/syscall/lx_pipe.c

@@ -65,7 +65,7 @@ lx_pipe_setsz(stdata_t *str, uint_t size, boolean_t is_init)
 	stdata_t *mate;
 	lx_zone_data_t *lxzd = ztolxzd(curzone);
 	uint_t max_size = lxzd->lxzd_pipe_max_sz;
-
+	fifonode_t *fnp1, *fnp2;
 
 	size = P2ROUNDUP(size, PAGESIZE);
 	if (size == 0) {
@@ -94,7 +94,14 @@ lx_pipe_setsz(stdata_t *str, uint_t size, boolean_t is_init)
 	}
 
 	if (!STRMATED(str)) {
-		return (strqset(RD(str->sd_wrq), QHIWAT, 0, (intptr_t)size));
+		err = strqset(RD(str->sd_wrq), QHIWAT, 0, (intptr_t)size);
+		if (err == 0) {
+			fnp1 = VTOF(str->sd_vnode);
+			mutex_enter(&fnp1->fn_lock->flk_lock);
+			fnp1->fn_hiwat = size;
+			mutex_exit(&fnp1->fn_lock->flk_lock);
+		}
+		return (err);
 	}
 
 	/*
@@ -116,6 +123,28 @@ lx_pipe_setsz(stdata_t *str, uint_t size, boolean_t is_init)
 	if ((err = strqset(RD(str->sd_wrq), QHIWAT, 0, (intptr_t)size)) == 0) {
 		err = strqset(RD(mate->sd_wrq), QHIWAT, 0, (intptr_t)size);
 	}
+
+	if (err == 0) {
+		fnp1 = VTOF(str->sd_vnode);
+		fnp2 = VTOF(str->sd_mate->sd_vnode);
+
+		/*
+		 * See fnode_constructor. Both sides should have the same
+		 * lock. We expect our callers to ensure that the vnodes
+		 * are VFIFO and have v_op == fifovnops.
+		 */
+		ASSERT(str->sd_vnode->v_type == VFIFO);
+		ASSERT(str->sd_mate->sd_vnode->v_type == VFIFO);
+		ASSERT(fnp1->fn_lock == fnp2->fn_lock);
+
+		mutex_enter(&fnp1->fn_lock->flk_lock);
+
+		fnp1->fn_hiwat = size;
+		fnp2->fn_hiwat = size;
+
+		mutex_exit(&fnp1->fn_lock->flk_lock);
+	}
+
 	return (err);
 }
 

usr/src/uts/common/fs/fifofs/fifosubr.c

@@ -22,6 +22,7 @@
 
 /*
  * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2017 Joyent, Inc.
  */
 
 /*
@@ -61,7 +62,6 @@
 #if FIFODEBUG
 int Fifo_fastmode = 1;		/* pipes/fifos will be opened in fast mode */
 int Fifo_verbose = 0;		/* msg when switching out of fast mode */
-int Fifohiwat = FIFOHIWAT;	/* Modifiable FIFO high water mark */
 #endif
 
 /*
@@ -196,6 +196,7 @@ fnode_constructor(void *buf, void *cdrarg, int kmflags)
 		fnp->fn_dest = fnp;
 		fnp->fn_mp = NULL;
 		fnp->fn_count = 0;
+		fnp->fn_hiwat = FIFOHIWAT;
 		fnp->fn_rsynccnt = 0;
 		fnp->fn_wsynccnt = 0;
 		fnp->fn_wwaitcnt = 0;
@@ -388,11 +389,7 @@ fifoinit(int fstype, char *name)
 	    pipe_constructor, pipe_destructor, NULL,
 	    (void *)(sizeof (fifodata_t)), NULL, 0);
 
-#if FIFODEBUG
-	if (Fifohiwat < FIFOHIWAT)
-		Fifohiwat = FIFOHIWAT;
-#endif /* FIFODEBUG */
-	fifo_strdata.qi_minfo->mi_hiwat = Fifohiwat;
+	fifo_strdata.qi_minfo->mi_hiwat = FIFOHIWAT;
 
 	return (0);
 }
@@ -1164,7 +1161,8 @@ fifo_wakewriter(fifonode_t *fn_dest, fifolock_t *fn_lock)
 	int fn_dflag = fn_dest->fn_flag;
 
 	ASSERT(MUTEX_HELD(&fn_lock->flk_lock));
-	ASSERT(fn_dest->fn_dest->fn_count < Fifohiwat);
+	ASSERT(fn_dest->fn_dest->fn_count < fn_dest->fn_dest->fn_hiwat);
+
 	if ((fn_dflag & FIFOWANTW)) {
 		cv_broadcast(&fn_dest->fn_wait_cv);
 	}

usr/src/uts/common/fs/fifofs/fifovnops.c

@@ -28,7 +28,7 @@
  */
 
 /*
- * Copyright 2015, Joyent, Inc.
+ * Copyright 2017, Joyent, Inc.
  * Copyright (c) 2017 by Delphix. All rights reserved.
  */
 
@@ -787,11 +787,11 @@ fifo_read(struct vnode *vp, struct uio *uiop, int ioflag, struct cred *crp,
 	/*
 	 * wake up any blocked writers, processes
 	 * sleeping on POLLWRNORM, or processes waiting for SIGPOLL
-	 * Note: checking for fn_count < Fifohiwat emulates
+	 * Note: checking for fn_count < fn_hiwat emulates
 	 * STREAMS functionality when low water mark is 0
 	 */
 	if (fn_dest->fn_flag & (FIFOWANTW | FIFOHIWATW) &&
-	    fnp->fn_count < Fifohiwat) {
+	    fnp->fn_count < fn_dest->fn_hiwat) {
 		fifo_wakewriter(fn_dest, fn_lock);
 	}
 	goto done;
@@ -904,7 +904,7 @@ fifo_write(vnode_t *vp, uio_t *uiop, int ioflag, cred_t *crp,
 		/*
 		 * check to make sure we are not over high water mark
 		 */
-		while (fn_dest->fn_count >= Fifohiwat) {
+		while (fn_dest->fn_count >= fn_dest->fn_hiwat) {
 			/*
 			 * Indicate that we have gone over high
 			 * water mark
@@ -962,7 +962,7 @@ fifo_write(vnode_t *vp, uio_t *uiop, int ioflag, cred_t *crp,
 		 * then we must break the message up into PIPE_BUF
 		 * chunks to stay compliant with STREAMS
 		 */
-		if (uiop->uio_resid + fn_dest->fn_count > Fifohiwat)
+		if (uiop->uio_resid + fn_dest->fn_count > fn_dest->fn_hiwat)
 			size = MIN(uiop->uio_resid, PIPE_BUF);
 		else
 			size = uiop->uio_resid;
@@ -1198,7 +1198,8 @@ fifo_fastioctl(vnode_t *vp, int cmd, intptr_t arg, int mode, cred_t *cr,
 		if (arg != 0) {
 			goto turn_fastoff;
 		}
-		*rvalp = (fnp->fn_dest->fn_count < Fifohiwat) ? 1 : 0;
+		*rvalp = (fnp->fn_dest->fn_count < fnp->fn_dest->fn_hiwat) ?
+		    1 : 0;
 		mutex_exit(&fn_lock->flk_lock);
 		return (0);
 
@@ -1817,7 +1818,7 @@ fifo_poll(vnode_t *vp, short events, int anyyet, short *reventsp,
 			retevents = POLLHUP;
 	} else if (events & (POLLWRNORM | POLLWRBAND)) {
 		if (events & POLLWRNORM) {
-			if (fn_dest->fn_count < Fifohiwat)
+			if (fn_dest->fn_count < fn_dest->fn_hiwat)
 				retevents = POLLWRNORM;
 			else
 				fnp->fn_flag |= FIFOHIWATW;

usr/src/uts/common/sys/fs/fifonode.h

@@ -21,6 +21,7 @@
 /*
  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
+ * Copyright 2017 Joyent, Inc.
  */
 
 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
@@ -83,6 +84,7 @@ struct fifonode {
 	struct msgb	*fn_tail;	/* last message to read */
 	fifolock_t	*fn_lock;	/* pointer to per fifo lock */
 	uint_t		fn_count;	/* Number of bytes on fn_mp */
+	uint_t		fn_hiwat;	/* pipe (fifofast) high water */
 	kcondvar_t	fn_wait_cv;	/* fifo conditional variable */
 	ushort_t	fn_wcnt;	/* number of writers */
 	ushort_t	fn_rcnt;	/* number of readers */
@@ -147,16 +149,6 @@ typedef struct fifodata {
 
 #if defined(_KERNEL)
 
-/*
- * Fifohiwat defined as a variable is to allow tuning of the high
- * water mark if needed. It is not meant to be released.
- */
-#if FIFODEBUG
-extern int Fifohiwat;
-#else /* FIFODEBUG */
-#define	Fifohiwat	FIFOHIWAT
-#endif /* FIFODEBUG */
-
 extern struct vnodeops *fifo_vnodeops;
 extern const struct fs_operation_def fifo_vnodeops_template[];
 extern struct kmem_cache *fnode_cache;