From 1f319c1cdd12d4c64055f4edc6f870aa2289f752 Mon Sep 17 00:00:00 2001
From: huanghua <huanghua>
Date: Tue, 25 Sep 2007 02:42:36 +0000
Subject: [PATCH] Branch b1_6 b=13685 b=11401 i=adilger i=tappro
fix race condition in stopping statahead thread.
---
lustre/llite/statahead.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/lustre/llite/statahead.c b/lustre/llite/statahead.c
index e1e189297a..c3f80d01d2 100644
--- a/lustre/llite/statahead.c
+++ b/lustre/llite/statahead.c
@@ -77,7 +77,6 @@ static void ll_sai_put(struct ll_statahead_info *sai)
if (atomic_dec_and_lock(&sai->sai_refc, &lli->lli_lock)) {
struct ll_sai_entry *entry, *next;
- LASSERT(sai->sai_thread.t_flags & SVC_STOPPED);
list_for_each_entry_safe(entry, next, &sai->sai_entries,
se_list) {
list_del(&entry->se_list);
@@ -118,6 +117,7 @@ static struct ll_sai_entry *ll_sai_entry_get(struct ll_statahead_info *sai,
RETURN(entry);
}
+/* inside lli_lock */
static void ll_sai_entry_set(struct ll_statahead_info *sai, int index,
int stat)
{
@@ -591,9 +591,12 @@ static int ll_statahead_thread(void *arg)
}
EXIT;
out:
+ spin_lock(&lli->lli_lock);
thread->t_flags = SVC_STOPPED;
cfs_waitq_signal(&thread->t_ctl_waitq);
lli->lli_opendir_pid = 0; /* avoid statahead again */
+ spin_unlock(&lli->lli_lock);
+
ll_sai_put(sai);
dput(parent);
CDEBUG(D_READA, "stopped statahead thread, pid %d for %s\n",
@@ -607,21 +610,21 @@ void ll_stop_statahead(struct inode *inode)
struct ll_inode_info *lli = ll_i2info(inode);
struct ptlrpc_thread *thread;
+ spin_lock(&lli->lli_lock);
/* don't check pid here. upon fork, if parent closedir before child,
* child will not have chance to stop this thread. */
lli->lli_opendir_pid = 0;
- spin_lock(&lli->lli_lock);
- if (lli->lli_sai) {
+ if (lli->lli_sai && (lli->lli_sai->sai_thread.t_flags & SVC_RUNNING)) {
struct l_wait_info lwi = { 0 };
ll_sai_get(lli->lli_sai);
+ thread = &lli->lli_sai->sai_thread;
+ thread->t_flags = SVC_STOPPING;
+ cfs_waitq_signal(&thread->t_ctl_waitq);
spin_unlock(&lli->lli_lock);
CDEBUG(D_READA, "stopping statahead thread, pid %d\n",
current->pid);
- thread = &lli->lli_sai->sai_thread;
- thread->t_flags = SVC_STOPPING;
- cfs_waitq_signal(&thread->t_ctl_waitq);
l_wait_event(thread->t_ctl_waitq, thread->t_flags & SVC_STOPPED,
&lwi);
ll_sai_put(lli->lli_sai);
--
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