All of lore.kernel.org
 help / color / mirror / Atom feed
From: Julien Grall <julien@xen.org>
To: xen-devel@lists.xenproject.org
Cc: raphning@amazon.co.uk, doebel@amazon.de,
	Julien Grall <jgrall@amazon.com>,
	Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>,
	Juergen Gross <jgross@suse.com>, Julien Grall <julien@xen.org>
Subject: [PATCH 04/10] tools/xenstored: Limit the number of requests a connection can delay
Date: Wed, 16 Jun 2021 15:43:18 +0100	[thread overview]
Message-ID: <20210616144324.31652-5-julien@xen.org> (raw)
In-Reply-To: <20210616144324.31652-1-julien@xen.org>

From: Julien Grall <jgrall@amazon.com>

Currently, only liveupdate request can be delayed. The request can only
be performed by a privileged connection (e.g. dom0). So it is fine to
have no limits.

In a follow-up patch we will want to delay request for unprivileged
connection as well. So it is best to apply a limit.

For now and for simplicity, only a single request can be delayed
for a given unprivileged connection.

Take the opportunity to tweak the prototype and provide a way to
bypass the quota check. This would be useful when the function
is called from the restore code.

Signed-off-by: Julien Grall <jgrall@amazon.com>
---
 tools/xenstore/xenstored_control.c |  2 +-
 tools/xenstore/xenstored_core.c    | 11 ++++++++++-
 tools/xenstore/xenstored_core.h    |  3 ++-
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/tools/xenstore/xenstored_control.c b/tools/xenstore/xenstored_control.c
index 7acc2d134f9f..1c24d4869eab 100644
--- a/tools/xenstore/xenstored_control.c
+++ b/tools/xenstore/xenstored_control.c
@@ -737,7 +737,7 @@ static const char *lu_start(const void *ctx, struct connection *conn,
 	lu_status->timeout = to;
 	lu_status->started_at = time(NULL);
 
-	errno = delay_request(conn, conn->in, do_lu_start, NULL);
+	errno = delay_request(conn, conn->in, do_lu_start, NULL, false);
 
 	return NULL;
 }
diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index 41b26d7094c8..51d210828922 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -279,10 +279,19 @@ static void call_delayed(struct connection *conn, struct delayed_request *req)
 }
 
 int delay_request(struct connection *conn, struct buffered_data *in,
-		  bool (*func)(struct delayed_request *), void *data)
+		  bool (*func)(struct delayed_request *), void *data,
+		  bool no_quota_check)
 {
 	struct delayed_request *req;
 
+	/*
+	 * Only allow one request can be delayed for an unprivileged
+	 * connection.
+	 */
+	if (!no_quota_check && domain_is_unprivileged(conn) &&
+	    !list_empty(&conn->delayed))
+		return ENOSPC;
+
 	req = talloc(in, struct delayed_request);
 	if (!req)
 		return ENOMEM;
diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
index 89ce155e755b..34839b34f6e9 100644
--- a/tools/xenstore/xenstored_core.h
+++ b/tools/xenstore/xenstored_core.h
@@ -213,7 +213,8 @@ char *get_parent(const void *ctx, const char *node);
 
 /* Delay a request. */
 int delay_request(struct connection *conn, struct buffered_data *in,
-		  bool (*func)(struct delayed_request *), void *data);
+		  bool (*func)(struct delayed_request *), void *data,
+		  bool no_quota_check);
 
 /* Tracing infrastructure. */
 void trace_create(const void *data, const char *type);
-- 
2.17.1



  parent reply	other threads:[~2021-06-16 14:43 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-16 14:43 [PATCH 00/10] tools/xenstored: Bug fixes + Improve Live-Update Julien Grall
2021-06-16 14:43 ` [PATCH 01/10] MAINTAINERS: Add myself as reviewers for tools/xenstore Julien Grall
2021-06-16 15:15   ` Juergen Gross
2021-06-16 14:43 ` [PATCH 02/10] tools/xenstored: Introduce lu_get_connection() and use it Julien Grall
2021-06-21  8:21   ` Luca Fancellu
2021-06-24  7:21   ` Juergen Gross
2021-06-16 14:43 ` [PATCH 03/10] tools/xenstore: Don't assume conn->in points to the LU request Julien Grall
2021-06-21  8:55   ` Luca Fancellu
2021-06-24  8:06     ` Julien Grall
2021-06-24  7:32   ` Juergen Gross
2021-06-24  7:34     ` Juergen Gross
2021-06-24  7:56       ` Luca Fancellu
2021-06-24  8:05         ` Juergen Gross
2021-06-16 14:43 ` Julien Grall [this message]
2021-06-21  9:02   ` [PATCH 04/10] tools/xenstored: Limit the number of requests a connection can delay Luca Fancellu
2021-06-24  7:35   ` Juergen Gross
2021-06-16 14:43 ` [PATCH 05/10] tools/xenstored: xenstored_core.h should include fcntl.h Julien Grall
2021-06-21  9:03   ` Luca Fancellu
2021-06-24  7:36   ` Juergen Gross
2021-06-16 14:43 ` [PATCH 06/10] tools/xenstored: Introduce a wrapper for conn->funcs->can_{read, write} Julien Grall
2021-06-21  9:10   ` Luca Fancellu
2021-06-24  7:39   ` Juergen Gross
2021-06-16 14:43 ` [PATCH 07/10] tools/xenstored: delay_request: don't assume conn->in == in Julien Grall
2021-06-21  9:12   ` Luca Fancellu
2021-06-24  7:44   ` Juergen Gross
2021-06-24  7:58     ` Julien Grall
2021-06-16 14:43 ` [PATCH 08/10] tools/xenstored: Extend restore code to handle multiple input buffer Julien Grall
2021-06-21  9:21   ` Luca Fancellu
2021-06-24  8:30   ` Juergen Gross
2021-06-24  8:42     ` Julien Grall
2021-06-24  9:20       ` Juergen Gross
2021-06-16 14:43 ` [PATCH 09/10] tools/xenstored: Dump delayed requests Julien Grall
2021-06-21  9:27   ` Luca Fancellu
2021-06-24  8:41   ` Juergen Gross
2021-06-24 10:28     ` Julien Grall
2021-06-24 10:45       ` Juergen Gross
2021-06-24 10:46         ` Julien Grall
2021-06-24 11:02           ` Juergen Gross
2021-06-24 11:17             ` Julien Grall
2021-06-16 14:43 ` [PATCH 10/10] tools/xenstored: Delay new transaction while Live-Update is pending Julien Grall
2021-06-21  9:30   ` Luca Fancellu
2021-06-24  9:23   ` Juergen Gross
2021-06-24 10:43 ` [PATCH 00/10] tools/xenstored: Bug fixes + Improve Live-Update Julien Grall

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=20210616144324.31652-5-julien@xen.org \
    --to=julien@xen.org \
    --cc=doebel@amazon.de \
    --cc=iwj@xenproject.org \
    --cc=jgrall@amazon.com \
    --cc=jgross@suse.com \
    --cc=raphning@amazon.co.uk \
    --cc=wl@xen.org \
    --cc=xen-devel@lists.xenproject.org \
    --subject='Re: [PATCH 04/10] tools/xenstored: Limit the number of requests a connection can delay' \
    /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

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.