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author | David Teigland <teigland@redhat.com> | 2006-10-31 11:55:56 -0600 |
---|---|---|
committer | Steven Whitehouse <swhiteho@redhat.com> | 2006-11-30 10:35:10 -0500 |
commit | d4400156d415540086c34a06e5d233122d6bf56a (patch) | |
tree | 747e4d270fb453d57926d6b6cab564664d9d2c0f /fs | |
parent | 435618b75b82b5ee511cc01fcdda9c44adb2f4bd (diff) | |
download | linux-stable-d4400156d415540086c34a06e5d233122d6bf56a.tar.gz linux-stable-d4400156d415540086c34a06e5d233122d6bf56a.tar.bz2 linux-stable-d4400156d415540086c34a06e5d233122d6bf56a.zip |
[DLM] fix requestqueue race
Red Hat BZ 211914
There's a race between dlm_recoverd (1) enabling locking and (2) clearing
out the requestqueue, and dlm_recvd (1) checking if locking is enabled and
(2) adding a message to the requestqueue. An order of recoverd(1),
recvd(1), recvd(2), recoverd(2) will result in a message being left on the
requestqueue. The fix is to have dlm_recvd check if dlm_recoverd has
enabled locking after taking the mutex for the requestqueue and if it has
processing the message instead of queueing it.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/dlm/lock.c | 15 | ||||
-rw-r--r-- | fs/dlm/requestqueue.c | 21 | ||||
-rw-r--r-- | fs/dlm/requestqueue.h | 2 |
3 files changed, 29 insertions, 9 deletions
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c index 3f2befa4797b..6088a16926bf 100644 --- a/fs/dlm/lock.c +++ b/fs/dlm/lock.c @@ -3028,10 +3028,17 @@ int dlm_receive_message(struct dlm_header *hd, int nodeid, int recovery) while (1) { if (dlm_locking_stopped(ls)) { - if (!recovery) - dlm_add_requestqueue(ls, nodeid, hd); - error = -EINTR; - goto out; + if (recovery) { + error = -EINTR; + goto out; + } + error = dlm_add_requestqueue(ls, nodeid, hd); + if (error == -EAGAIN) + continue; + else { + error = -EINTR; + goto out; + } } if (lock_recovery_try(ls)) diff --git a/fs/dlm/requestqueue.c b/fs/dlm/requestqueue.c index 7b2b089634a2..0226d2a0a0fa 100644 --- a/fs/dlm/requestqueue.c +++ b/fs/dlm/requestqueue.c @@ -30,26 +30,39 @@ struct rq_entry { * lockspace is enabled on some while still suspended on others. */ -void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_header *hd) +int dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_header *hd) { struct rq_entry *e; int length = hd->h_length; + int rv = 0; if (dlm_is_removed(ls, nodeid)) - return; + return 0; e = kmalloc(sizeof(struct rq_entry) + length, GFP_KERNEL); if (!e) { log_print("dlm_add_requestqueue: out of memory\n"); - return; + return 0; } e->nodeid = nodeid; memcpy(e->request, hd, length); + /* We need to check dlm_locking_stopped() after taking the mutex to + avoid a race where dlm_recoverd enables locking and runs + process_requestqueue between our earlier dlm_locking_stopped check + and this addition to the requestqueue. */ + mutex_lock(&ls->ls_requestqueue_mutex); - list_add_tail(&e->list, &ls->ls_requestqueue); + if (dlm_locking_stopped(ls)) + list_add_tail(&e->list, &ls->ls_requestqueue); + else { + log_debug(ls, "dlm_add_requestqueue skip from %d", nodeid); + kfree(e); + rv = -EAGAIN; + } mutex_unlock(&ls->ls_requestqueue_mutex); + return rv; } int dlm_process_requestqueue(struct dlm_ls *ls) diff --git a/fs/dlm/requestqueue.h b/fs/dlm/requestqueue.h index 349f0d292d95..6a53ea03335d 100644 --- a/fs/dlm/requestqueue.h +++ b/fs/dlm/requestqueue.h @@ -13,7 +13,7 @@ #ifndef __REQUESTQUEUE_DOT_H__ #define __REQUESTQUEUE_DOT_H__ -void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_header *hd); +int dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_header *hd); int dlm_process_requestqueue(struct dlm_ls *ls); void dlm_wait_requestqueue(struct dlm_ls *ls); void dlm_purge_requestqueue(struct dlm_ls *ls); |