diff options
author | Joel Becker <joel.becker@oracle.com> | 2007-02-03 06:04:20 -0500 |
---|---|---|
committer | Mark Fasheh <mark.fasheh@oracle.com> | 2007-03-14 17:37:12 -0400 |
commit | e6c352dbc0f4dc7e3f82feafb9e6207c5814a189 (patch) | |
tree | 796049268fa7a90ee87f2f01a109354f7a54ce01 /fs/ocfs2/cluster | |
parent | c24f72cc7ca829bbad0532ddf315ace3ae1c359e (diff) |
ocfs2: Concurrent access of o2hb_region->hr_task was not locked
This means that a build-up and a teardown could race which would result in a
double-kthread_stop().
Protect the setting and clearing of hr_task with o2hb_live_lock, as it's not
a common thing and not performance critical.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Diffstat (limited to 'fs/ocfs2/cluster')
-rw-r--r-- | fs/ocfs2/cluster/heartbeat.c | 44 |
1 files changed, 32 insertions, 12 deletions
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c index 0f2cfecd42c0..eba282da500e 100644 --- a/fs/ocfs2/cluster/heartbeat.c +++ b/fs/ocfs2/cluster/heartbeat.c | |||
@@ -1234,6 +1234,7 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg, | |||
1234 | const char *page, | 1234 | const char *page, |
1235 | size_t count) | 1235 | size_t count) |
1236 | { | 1236 | { |
1237 | struct task_struct *hb_task; | ||
1237 | long fd; | 1238 | long fd; |
1238 | int sectsize; | 1239 | int sectsize; |
1239 | char *p = (char *)page; | 1240 | char *p = (char *)page; |
@@ -1319,20 +1320,28 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg, | |||
1319 | */ | 1320 | */ |
1320 | atomic_set(®->hr_steady_iterations, O2HB_LIVE_THRESHOLD + 1); | 1321 | atomic_set(®->hr_steady_iterations, O2HB_LIVE_THRESHOLD + 1); |
1321 | 1322 | ||
1322 | reg->hr_task = kthread_run(o2hb_thread, reg, "o2hb-%s", | 1323 | hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s", |
1323 | reg->hr_item.ci_name); | 1324 | reg->hr_item.ci_name); |
1324 | if (IS_ERR(reg->hr_task)) { | 1325 | if (IS_ERR(hb_task)) { |
1325 | ret = PTR_ERR(reg->hr_task); | 1326 | ret = PTR_ERR(hb_task); |
1326 | mlog_errno(ret); | 1327 | mlog_errno(ret); |
1327 | reg->hr_task = NULL; | ||
1328 | goto out; | 1328 | goto out; |
1329 | } | 1329 | } |
1330 | 1330 | ||
1331 | spin_lock(&o2hb_live_lock); | ||
1332 | reg->hr_task = hb_task; | ||
1333 | spin_unlock(&o2hb_live_lock); | ||
1334 | |||
1331 | ret = wait_event_interruptible(o2hb_steady_queue, | 1335 | ret = wait_event_interruptible(o2hb_steady_queue, |
1332 | atomic_read(®->hr_steady_iterations) == 0); | 1336 | atomic_read(®->hr_steady_iterations) == 0); |
1333 | if (ret) { | 1337 | if (ret) { |
1334 | kthread_stop(reg->hr_task); | 1338 | spin_lock(&o2hb_live_lock); |
1339 | hb_task = reg->hr_task; | ||
1335 | reg->hr_task = NULL; | 1340 | reg->hr_task = NULL; |
1341 | spin_unlock(&o2hb_live_lock); | ||
1342 | |||
1343 | if (hb_task) | ||
1344 | kthread_stop(hb_task); | ||
1336 | goto out; | 1345 | goto out; |
1337 | } | 1346 | } |
1338 | 1347 | ||
@@ -1354,10 +1363,17 @@ out: | |||
1354 | static ssize_t o2hb_region_pid_read(struct o2hb_region *reg, | 1363 | static ssize_t o2hb_region_pid_read(struct o2hb_region *reg, |
1355 | char *page) | 1364 | char *page) |
1356 | { | 1365 | { |
1357 | if (!reg->hr_task) | 1366 | pid_t pid = 0; |
1367 | |||
1368 | spin_lock(&o2hb_live_lock); | ||
1369 | if (reg->hr_task) | ||
1370 | pid = reg->hr_task->pid; | ||
1371 | spin_unlock(&o2hb_live_lock); | ||
1372 | |||
1373 | if (!pid) | ||
1358 | return 0; | 1374 | return 0; |
1359 | 1375 | ||
1360 | return sprintf(page, "%u\n", reg->hr_task->pid); | 1376 | return sprintf(page, "%u\n", pid); |
1361 | } | 1377 | } |
1362 | 1378 | ||
1363 | struct o2hb_region_attribute { | 1379 | struct o2hb_region_attribute { |
@@ -1495,13 +1511,17 @@ out: | |||
1495 | static void o2hb_heartbeat_group_drop_item(struct config_group *group, | 1511 | static void o2hb_heartbeat_group_drop_item(struct config_group *group, |
1496 | struct config_item *item) | 1512 | struct config_item *item) |
1497 | { | 1513 | { |
1514 | struct task_struct *hb_task; | ||
1498 | struct o2hb_region *reg = to_o2hb_region(item); | 1515 | struct o2hb_region *reg = to_o2hb_region(item); |
1499 | 1516 | ||
1500 | /* stop the thread when the user removes the region dir */ | 1517 | /* stop the thread when the user removes the region dir */ |
1501 | if (reg->hr_task) { | 1518 | spin_lock(&o2hb_live_lock); |
1502 | kthread_stop(reg->hr_task); | 1519 | hb_task = reg->hr_task; |
1503 | reg->hr_task = NULL; | 1520 | reg->hr_task = NULL; |
1504 | } | 1521 | spin_unlock(&o2hb_live_lock); |
1522 | |||
1523 | if (hb_task) | ||
1524 | kthread_stop(hb_task); | ||
1505 | 1525 | ||
1506 | config_item_put(item); | 1526 | config_item_put(item); |
1507 | } | 1527 | } |