From: Steven Whitehouse <swhiteho@redhat.com>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [PATCH 2/4] [DLM] fix a couple of races
Date: Mon, 18 Jun 2007 15:54:28 +0100 [thread overview]
Message-ID: <11821784801162-git-send-email-swhiteho@redhat.com> (raw)
In-Reply-To: <1182178478593-git-send-email-swhiteho@redhat.com>
Fix two races in fs/dlm/config.c:
(1) Grab the configfs subsystem semaphore before calling
config_group_find_obj() in get_space(). This solves a potential race
between get_space() and concurrent mkdir(2) or rmdir(2).
(2) Grab a reference on the found config_item _while_ holding the configfs
subsystem semaphore in get_comm(), and not after it. This solves a
potential race between get_comm() and concurrent rmdir(2).
Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
---
fs/dlm/config.c | 15 +++++++++++----
1 files changed, 11 insertions(+), 4 deletions(-)
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WARNING: multiple messages have this Message-ID (diff)
From: Steven Whitehouse <swhiteho@redhat.com>
To: cluster-devel@redhat.com, linux-kernel@vger.kernel.org
Cc: Satyam Sharma <ssatyam@cse.iitk.ac.in>,
David Teigland <teigland@redhat.com>,
Steven Whitehouse <swhiteho@redhat.com>
Subject: [PATCH 2/4] [DLM] fix a couple of races
Date: Mon, 18 Jun 2007 15:54:28 +0100 [thread overview]
Message-ID: <11821784801162-git-send-email-swhiteho@redhat.com> (raw)
In-Reply-To: <1182178478593-git-send-email-swhiteho@redhat.com>
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Fix two races in fs/dlm/config.c:
(1) Grab the configfs subsystem semaphore before calling
config_group_find_obj() in get_space(). This solves a potential race
between get_space() and concurrent mkdir(2) or rmdir(2).
(2) Grab a reference on the found config_item _while_ holding the configfs
subsystem semaphore in get_comm(), and not after it. This solves a
potential race between get_comm() and concurrent rmdir(2).
Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
---
fs/dlm/config.c | 15 +++++++++++----
1 files changed, 11 insertions(+), 4 deletions(-)
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diff --git a/fs/dlm/config.c b/fs/dlm/config.c
index 822abdc..5a3d390 100644
--- a/fs/dlm/config.c
+++ b/fs/dlm/config.c
@@ -748,9 +748,16 @@ static ssize_t node_weight_write(struct node *nd, const char *buf, size_t len)
static struct space *get_space(char *name)
{
+ struct config_item *i;
+
if (!space_list)
return NULL;
- return to_space(config_group_find_obj(space_list, name));
+
+ down(&space_list->cg_subsys->su_sem);
+ i = config_group_find_obj(space_list, name);
+ up(&space_list->cg_subsys->su_sem);
+
+ return to_space(i);
}
static void put_space(struct space *sp)
@@ -776,20 +783,20 @@ static struct comm *get_comm(int nodeid, struct sockaddr_storage *addr)
if (cm->nodeid != nodeid)
continue;
found = 1;
+ config_item_get(i);
break;
} else {
if (!cm->addr_count ||
memcmp(cm->addr[0], addr, sizeof(*addr)))
continue;
found = 1;
+ config_item_get(i);
break;
}
}
up(&clusters_root.subsys.su_sem);
- if (found)
- config_item_get(i);
- else
+ if (!found)
cm = NULL;
return cm;
}
next prev parent reply other threads:[~2007-06-18 14:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-18 14:54 [Cluster-devel] [GFS2/DLM] Some small bug fixes Steven Whitehouse
2007-06-18 14:54 ` Steven Whitehouse
2007-06-18 14:54 ` [Cluster-devel] [PATCH 1/4] [GFS2] flush the glock completely in inode_go_sync Steven Whitehouse
2007-06-18 14:54 ` Steven Whitehouse
2007-06-18 14:54 ` Steven Whitehouse [this message]
2007-06-18 14:54 ` [PATCH 2/4] [DLM] fix a couple of races Steven Whitehouse
2007-06-18 14:54 ` [Cluster-devel] [PATCH 3/4] [GFS2] use zero_user_page Steven Whitehouse
2007-06-18 14:54 ` Steven Whitehouse
2007-06-18 14:54 ` [Cluster-devel] [PATCH 4/4] [DLM] keep dlm from panicing when traversing rsb list in debugfs Steven Whitehouse
2007-06-18 14:54 ` Steven Whitehouse
2007-06-18 15:13 ` [Cluster-devel] [GFS2/DLM] Pull request Steven Whitehouse
2007-06-18 15:13 ` Steven Whitehouse
2007-06-18 15:30 ` [Cluster-devel] " Steven Whitehouse
2007-06-18 15:30 ` Steven Whitehouse
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