Revised man page and defaults

Signed-off-by: Rich Ercolani <[email protected]>

lib/libzfs_core/libzfs_core.c

@@ -615,9 +615,10 @@ max_pipe_buffer(int infd)
 	 * And since the problem is in waking up the writer, there's nothing
 	 * we can do about it from here.
 	 *
-	 * So we add this workaround for people who get bitten.
+	 * So if people want to, they can set this, but they
+	 * may regret it...
 	 */
-	if (getenv("ZFS_NO_PIPE_MAX") != NULL)
+	if (getenv("ZFS_SET_PIPE_MAX") == NULL)
 		return (cur);
 	if (cur < max && fcntl(infd, F_SETPIPE_SZ, max) != -1)
 		cur = max;

man/man8/zfs.8

@@ -725,6 +725,14 @@ to use
 to mount ZFS datasets.
 This option is provided for backwards compatibility with older ZFS versions.
 .El
+.Bl -tag -width "ZFS_SET_PIPE_MAX"
+.It Sy ZFS_SET_PIPE_MAX
+Tells
+.Nm zfs
+to set the maximum pipe size for sends/recieves.
+Disabled by default on Linux
+due to an unfixed deadlock in Linux's pipe size handling code.
+.El
 .
 .Sh INTERFACE STABILITY
 .Sy Committed .