This patch fixes the following hole.
dlmlock tries to create a new lock on a lockres that is on purge list. It calls
dlm_get_lockresource and later adds a lock to blocked list. But in this window,
dlm_thread can purge the lockres and unhash it. This will cause a BUG, as when
the AST comes back from the master lockres is not found
This patch marks the lockres with a new state DLM_LOCK_RES_IN_USE which would
protect lockres from dlm_thread purging it.
Signed-off-by: Srinivas Eeda <srinivas.e...@oracle.com>
---
fs/ocfs2/dlm/dlmcommon.h | 1 +
fs/ocfs2/dlm/dlmlock.c | 4 ++++
fs/ocfs2/dlm/dlmmaster.c | 5 ++++-
fs/ocfs2/dlm/dlmthread.c | 1 +
4 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h
index 0102be3..6cf3c08 100644
--- a/fs/ocfs2/dlm/dlmcommon.h
+++ b/fs/ocfs2/dlm/dlmcommon.h
@@ -279,6 +279,7 @@ static inline void __dlm_set_joining_node(struct dlm_ctxt
*dlm,
#define DLM_LOCK_RES_DIRTY 0x00000008
#define DLM_LOCK_RES_IN_PROGRESS 0x00000010
#define DLM_LOCK_RES_MIGRATING 0x00000020
+#define DLM_LOCK_RES_IN_USE 0x00000100
#define DLM_LOCK_RES_DROPPING_REF 0x00000040
#define DLM_LOCK_RES_BLOCK_DIRTY 0x00001000
#define DLM_LOCK_RES_SETREF_INPROG 0x00002000
diff --git a/fs/ocfs2/dlm/dlmlock.c b/fs/ocfs2/dlm/dlmlock.c
index 7333377..501ac40 100644
--- a/fs/ocfs2/dlm/dlmlock.c
+++ b/fs/ocfs2/dlm/dlmlock.c
@@ -134,6 +134,8 @@ static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm,
if (status != DLM_NORMAL &&
lock->ml.node != dlm->node_num) {
/* erf. state changed after lock was dropped. */
+ /* DLM_LOCK_RES_IN_USE is set in dlm_get_lock_resource */
+ res->state &= ~DLM_LOCK_RES_IN_USE;
spin_unlock(&res->spinlock);
dlm_error(status);
return status;
@@ -180,6 +182,7 @@ static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm,
kick_thread = 1;
}
}
+ res->state &= ~DLM_LOCK_RES_IN_USE;
/* reduce the inflight count, this may result in the lockres
* being purged below during calc_usage */
if (lock->ml.node == dlm->node_num)
@@ -246,6 +249,7 @@ static enum dlm_status dlmlock_remote(struct dlm_ctxt *dlm,
spin_lock(&res->spinlock);
res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
+ res->state &= ~DLM_LOCK_RES_IN_USE;
lock->lock_pending = 0;
if (status != DLM_NORMAL) {
if (status == DLM_RECOVERING &&
diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
index 9289b43..f0f2d97 100644
--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -719,6 +719,7 @@ lookup:
if (tmpres) {
int dropping_ref = 0;
+ tmpres->state |= DLM_LOCK_RES_IN_USE;
spin_unlock(&dlm->spinlock);
spin_lock(&tmpres->spinlock);
@@ -731,8 +732,10 @@ lookup:
if (tmpres->owner == dlm->node_num) {
BUG_ON(tmpres->state & DLM_LOCK_RES_DROPPING_REF);
dlm_lockres_grab_inflight_ref(dlm, tmpres);
- } else if (tmpres->state & DLM_LOCK_RES_DROPPING_REF)
+ } else if (tmpres->state & DLM_LOCK_RES_DROPPING_REF) {
+ tmpres->state &= ~DLM_LOCK_RES_IN_USE;
dropping_ref = 1;
+ }
spin_unlock(&tmpres->spinlock);
/* wait until done messaging the master, drop our ref to allow
diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c
index fb0be6c..2b82e0b 100644
--- a/fs/ocfs2/dlm/dlmthread.c
+++ b/fs/ocfs2/dlm/dlmthread.c
@@ -93,6 +93,7 @@ int __dlm_lockres_has_locks(struct dlm_lock_resource *res)
int __dlm_lockres_unused(struct dlm_lock_resource *res)
{
if (!__dlm_lockres_has_locks(res) &&
+ !(res->state & DLM_LOCK_RES_IN_USE) &&
(list_empty(&res->dirty) && !(res->state & DLM_LOCK_RES_DIRTY))) {
/* try not to scan the bitmap unless the first two
* conditions are already true */
--
1.5.6.5
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