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| author | Satyam Sharma <ssatyam@cse.iitk.ac.in> | 2007-05-08 12:18:58 +0400 |
|---|---|---|
| committer | Steven Whitehouse <swhiteho@redhat.com> | 2007-07-09 11:22:10 +0400 |
| commit | 3168b0780d06ace875696f8a648d04d6089654e5 (patch) | |
| tree | b93814b13155cce67432e1ed11bee58c9a5d5a50 /fs/dlm/config.c | |
| parent | b524fe646c9a226a847e30ca1221dc22e952f16b (diff) | |
| download | linux-3168b0780d06ace875696f8a648d04d6089654e5.tar.xz | |
[DLM] fix a couple of races
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>
Diffstat (limited to 'fs/dlm/config.c')
| -rw-r--r-- | fs/dlm/config.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/fs/dlm/config.c b/fs/dlm/config.c index 822abdcd1434..5a3d390cc826 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; } |