[Cluster-devel] [DLM] keep dlm from panicing when traversing rsb list in debugfs
Josef Bacik
jwhiter at redhat.com
Wed May 16 19:56:13 UTC 2007
Hello,
This problem was originally reported against GFS6.1, but the same issue exists
in upstream DLM. This patch keeps the rsb iterator assigning under the rsbtbl
list lock. Each time we process an rsb we grab a reference to it to make sure
it is not freed out from underneath us, and then put it when we get the next rsb
in the list or move onto another list. Thank you,
Josef
Signed-off-by: Josef Bacik <jwhiter at redhat.com>
diff --git a/fs/dlm/debug_fs.c b/fs/dlm/debug_fs.c
index 61ba670..9e27a16 100644
--- a/fs/dlm/debug_fs.c
+++ b/fs/dlm/debug_fs.c
@@ -17,6 +17,7 @@
#include <linux/debugfs.h>
#include "dlm_internal.h"
+#include "lock.h"
#define DLM_DEBUG_BUF_LEN 4096
static char debug_buf[DLM_DEBUG_BUF_LEN];
@@ -166,6 +167,9 @@ static int rsb_iter_next(struct rsb_iter
read_lock(&ls->ls_rsbtbl[i].lock);
if (!list_empty(&ls->ls_rsbtbl[i].list)) {
ri->next = ls->ls_rsbtbl[i].list.next;
+ ri->rsb = list_entry(ri->next, struct dlm_rsb,
+ res_hashchain);
+ dlm_hold_rsb(ri->rsb);
read_unlock(&ls->ls_rsbtbl[i].lock);
break;
}
@@ -176,6 +180,7 @@ static int rsb_iter_next(struct rsb_iter
if (ri->entry >= ls->ls_rsbtbl_size)
return 1;
} else {
+ struct dlm_rsb *old = ri->rsb;
i = ri->entry;
read_lock(&ls->ls_rsbtbl[i].lock);
ri->next = ri->next->next;
@@ -184,11 +189,13 @@ static int rsb_iter_next(struct rsb_iter
ri->next = NULL;
ri->entry++;
read_unlock(&ls->ls_rsbtbl[i].lock);
+ dlm_put_rsb(old);
goto top;
}
+ ri->rsb = list_entry(ri->next, struct dlm_rsb, res_hashchain);
read_unlock(&ls->ls_rsbtbl[i].lock);
+ dlm_put_rsb(old);
}
- ri->rsb = list_entry(ri->next, struct dlm_rsb, res_hashchain);
return 0;
}
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