libzfs: migrate single-use libzfs_set_pipe_max() to libzfs_core

Notably, this also means that the pipe is expanded before each
dataset is received, so updates to /p/s/f/pipe-max-size are reflected
for each new dataset

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Rich Ercolani <rincebrain@gmail.com>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #13133

lib/libzfs/Makefile.am

@@ -41,7 +41,6 @@ if BUILD_LINUX
 USER_C += \
 	os/linux/libzfs_mount_os.c \
 	os/linux/libzfs_pool_os.c \
-	os/linux/libzfs_sendrecv_os.c \
 	os/linux/libzfs_util_os.c
 endif
 

lib/libzfs/libzfs_impl.h

@@ -257,7 +257,6 @@ extern int libzfs_load_module(void);
 extern int zpool_relabel_disk(libzfs_handle_t *hdl, const char *path,
     const char *msg);
 extern int find_shares_object(differ_info_t *di);
-extern void libzfs_set_pipe_max(int infd);
 extern void zfs_commit_proto(const zfs_share_proto_t *);
 
 #ifdef	__cplusplus

lib/libzfs/libzfs_sendrecv.c

@@ -5243,13 +5243,6 @@ zfs_receive(libzfs_handle_t *hdl, const char *tosnap, nvlist_t *props,
 		return (-2);
 	}
 
-	/*
-	 * It is not uncommon for gigabytes to be processed in zfs receive.
-	 * Speculatively increase the buffer size if supported by the platform.
-	 */
-	if (S_ISFIFO(sb.st_mode))
-		libzfs_set_pipe_max(infd);
-
 	if (props) {
 		err = nvlist_lookup_string(props, "origin", &originsnap);
 		if (err && err != ENOENT)

lib/libzfs/os/freebsd/libzfs_compat.c

@@ -38,12 +38,6 @@
 #define	ZFS_KMOD	"openzfs"
 #endif
 
-void
-libzfs_set_pipe_max(int infd)
-{
-	/* FreeBSD automatically resizes */
-	(void) infd;
-}
 
 static int
 execvPe(const char *name, const char *path, char * const *argv,

lib/libzfs/os/linux/libzfs_sendrecv_os.c

@@ -1,52 +0,0 @@
-/*
- * CDDL HEADER START
- *
- * The contents of this file are subject to the terms of the
- * Common Development and Distribution License (the "License").
- * You may not use this file except in compliance with the License.
- *
- * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
- * or http://www.opensolaris.org/os/licensing.
- * See the License for the specific language governing permissions
- * and limitations under the License.
- *
- * When distributing Covered Code, include this CDDL HEADER in each
- * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
- * If applicable, add the following below this CDDL HEADER, with the
- * fields enclosed by brackets "[]" replaced with your own identifying
- * information: Portions Copyright [yyyy] [name of copyright owner]
- *
- * CDDL HEADER END
- */
-
-
-#include <libzfs.h>
-
-#include "../../libzfs_impl.h"
-
-#ifndef F_SETPIPE_SZ
-#define	F_SETPIPE_SZ (F_SETLEASE + 7)
-#endif /* F_SETPIPE_SZ */
-
-#ifndef F_GETPIPE_SZ
-#define	F_GETPIPE_SZ (F_GETLEASE + 7)
-#endif /* F_GETPIPE_SZ */
-
-void
-libzfs_set_pipe_max(int infd)
-{
-	FILE *procf = fopen("/proc/sys/fs/pipe-max-size", "re");
-
-	if (procf != NULL) {
-		unsigned long max_psize;
-		long cur_psize;
-		if (fscanf(procf, "%lu", &max_psize) > 0) {
-			cur_psize = fcntl(infd, F_GETPIPE_SZ);
-			if (cur_psize > 0 &&
-			    max_psize > (unsigned long) cur_psize)
-				fcntl(infd, F_SETPIPE_SZ,
-				    max_psize);
-		}
-		fclose(procf);
-	}
-}

lib/libzfs_core/libzfs_core.c

@@ -586,6 +586,30 @@ lzc_get_holds(const char *snapname, nvlist_t **holdsp)
 	return (lzc_ioctl(ZFS_IOC_GET_HOLDS, snapname, NULL, holdsp));
 }
 
+static void
+max_pipe_buffer(int infd)
+{
+#if __linux__
+	FILE *procf = fopen("/proc/sys/fs/pipe-max-size", "re");
+
+	if (procf != NULL) {
+		unsigned long max_psize;
+		long cur_psize;
+		if (fscanf(procf, "%lu", &max_psize) > 0) {
+			cur_psize = fcntl(infd, F_GETPIPE_SZ);
+			if (cur_psize > 0 &&
+			    max_psize > (unsigned long) cur_psize)
+				fcntl(infd, F_SETPIPE_SZ,
+				    max_psize);
+		}
+		fclose(procf);
+	}
+#else
+	/* FreeBSD automatically resizes */
+	(void) infd;
+#endif
+}
+
 /*
  * Generate a zfs send stream for the specified snapshot and write it to
  * the specified file descriptor.
@@ -811,6 +835,16 @@ recv_impl(const char *snapname, nvlist_t *recvdprops, nvlist_t *localprops,
 		*slashp = '\0';
 	}
 
+	/*
+	 * It is not uncommon for gigabytes to be processed by zfs receive.
+	 * Speculatively increase the buffer size if supported by the platform.
+	 */
+	struct stat sb;
+	if (fstat(input_fd, &sb) == -1)
+		return (errno);
+	if (S_ISFIFO(sb.st_mode))
+		max_pipe_buffer(input_fd);
+
 	/*
 	 * The begin_record is normally a non-byteswapped BEGIN record.
 	 * For resumable streams it may be set to any non-byteswapped