zfs/lib/libzfs/os/linux/libzfs_sendrecv_os.c

69 lines
1.8 KiB
C

/*
* 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)
{
#if __linux__
/*
* Sadly, Linux has an unfixed deadlock if you do SETPIPE_SZ on a pipe
* with data in it.
* cf. #13232, https://bugzilla.kernel.org/show_bug.cgi?id=212295
*
* And since the problem is in waking up the writer, there's nothing
* we can do about it from here.
*
* So if people want to, they can set this, but they
* may regret it...
*/
if (getenv("ZFS_SET_PIPE_MAX") == NULL)
return;
#endif
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);
}
}