From: David Vrabel <david.vrabel@citrix.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Juergen Gross <jgross@suse.com>,
linux-kernel@vger.kernel.org,
David Vrabel <david.vrabel@citrix.com>,
linux-fsdevel@vger.kernel.org, xen-devel@lists.xenproject.org,
Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: [PATCHv3 2/2] xenfs: replace xenbus and privcmd with symlinks
Date: Tue, 28 Jun 2016 19:06:07 +0100 [thread overview]
Message-ID: <1467137167-28546-3-git-send-email-david.vrabel@citrix.com> (raw)
In-Reply-To: <1467137167-28546-1-git-send-email-david.vrabel@citrix.com>
/proc/xen/xenbus does not work correctly. A read blocked waiting for
a xenstore message holds the mutex needed for atomic file position
updates. This blocks any writes on the same file handle, which can
deadlock if the write is needed to unblock the read.
/proc/xen/xenbus is supposed to be identical to the character device
/dev/xen/xenbus so replace the file with a symlink.
Similarly, replace /proc/xen/privcmd with a symlink since it should be
the same as /dev/xen/privcmd.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
v2:
- remove unneeded includes
---
drivers/xen/xenfs/super.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
index 8559a71..0f2e2cd 100644
--- a/drivers/xen/xenfs/super.c
+++ b/drivers/xen/xenfs/super.c
@@ -18,8 +18,6 @@
#include <xen/xen.h>
#include "xenfs.h"
-#include "../privcmd.h"
-#include "../xenbus/xenbus_comms.h"
#include <asm/xen/hypervisor.h>
@@ -45,16 +43,16 @@ static const struct file_operations capabilities_file_ops = {
static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
{
static struct tree_descr xenfs_files[] = {
- [2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
+ [2] = { "xenbus", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/xenbus" },
{ "capabilities", &capabilities_file_ops, S_IRUGO },
- { "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
+ { "privcmd", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/privcmd" },
{""},
};
static struct tree_descr xenfs_init_files[] = {
- [2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
+ [2] = { "xenbus", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/xenbus" },
{ "capabilities", &capabilities_file_ops, S_IRUGO },
- { "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
+ { "privcmd", NULL, S_IFLNK | S_IRWXUGO, "/dev/xen/privcmd" },
{ "xsd_kva", &xsd_kva_file_ops, S_IRUSR|S_IWUSR},
{ "xsd_port", &xsd_port_file_ops, S_IRUSR|S_IWUSR},
#ifdef CONFIG_XEN_SYMS
--
2.1.4
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-06-28 18:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-28 18:06 [PATCHv3 0/2] libfs, xenfs: replace /proc/xen/xenbus with a symlink David Vrabel
2016-06-28 18:06 ` [PATCHv3 1/2] libfs: allow simple_fill_super() to add symlinks David Vrabel
2016-07-11 9:38 ` David Vrabel
2016-06-28 18:06 ` David Vrabel [this message]
2016-06-29 4:50 ` [PATCHv3 2/2] xenfs: replace xenbus and privcmd with symlinks Juergen Gross
2016-08-23 0:47 ` [PATCHv3 0/2] libfs, xenfs: replace /proc/xen/xenbus with a symlink Doug Goldstein
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1467137167-28546-3-git-send-email-david.vrabel@citrix.com \
--to=david.vrabel@citrix.com \
--cc=boris.ostrovsky@oracle.com \
--cc=jgross@suse.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).