Srinivas Eeda
2010-Jun-22 17:33 UTC
[Ocfs2-devel] [PATCH 1/1] ocfs2 fix o2dlm dlm run purgelist(bug 9094491) - rev3
There are two problems in dlm_run_purgelist
1. If a lockres is found to be in use, dlm_run_purgelist keeps trying to purge
the same lockres instead of trying the next lockres.
2. When a lockres is found unused, dlm_run_purgelist releases lockres spinlock
before setting DLM_LOCK_RES_DROPPING_REF and calls dlm_purge_lockres.
spinlock is reacquired but in this window lockres can get reused. This leads
to BUG.
This patch modifies dlm_run_purgelist to skip lockres if it's in use and
purge
next lockres. It also sets DLM_LOCK_RES_DROPPING_REF before releasing the
lockres spinlock protecting it from getting reused.
Signed-off-by: Srinivas Eeda <srinivas.eeda at oracle.com>
---
fs/ocfs2/dlm/dlmthread.c | 76 ++++++++++++++++++++--------------------------
1 files changed, 33 insertions(+), 43 deletions(-)
diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c
index 11a6d1f..cb74689 100644
--- a/fs/ocfs2/dlm/dlmthread.c
+++ b/fs/ocfs2/dlm/dlmthread.c
@@ -152,45 +152,26 @@ void dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
spin_unlock(&dlm->spinlock);
}
-static int dlm_purge_lockres(struct dlm_ctxt *dlm,
+static void dlm_purge_lockres(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res)
{
int master;
int ret = 0;
- spin_lock(&res->spinlock);
- if (!__dlm_lockres_unused(res)) {
- mlog(0, "%s:%.*s: tried to purge but not unused\n",
- dlm->name, res->lockname.len, res->lockname.name);
- __dlm_print_one_lock_resource(res);
- spin_unlock(&res->spinlock);
- BUG();
- }
-
- if (res->state & DLM_LOCK_RES_MIGRATING) {
- mlog(0, "%s:%.*s: Delay dropref as this lockres is "
- "being remastered\n", dlm->name, res->lockname.len,
- res->lockname.name);
- /* Re-add the lockres to the end of the purge list */
- if (!list_empty(&res->purge)) {
- list_del_init(&res->purge);
- list_add_tail(&res->purge, &dlm->purge_list);
- }
- spin_unlock(&res->spinlock);
- return 0;
- }
+ assert_spin_locked(&dlm->spinlock);
+ assert_spin_locked(&res->spinlock);
master = (res->owner == dlm->node_num);
if (!master)
res->state |= DLM_LOCK_RES_DROPPING_REF;
- spin_unlock(&res->spinlock);
mlog(0, "purging lockres %.*s, master = %d\n", res->lockname.len,
res->lockname.name, master);
if (!master) {
/* drop spinlock... retake below */
+ spin_unlock(&res->spinlock);
spin_unlock(&dlm->spinlock);
spin_lock(&res->spinlock);
@@ -208,31 +189,35 @@ static int dlm_purge_lockres(struct dlm_ctxt *dlm,
mlog(0, "%s:%.*s: dlm_deref_lockres returned %d\n",
dlm->name, res->lockname.len, res->lockname.name, ret);
spin_lock(&dlm->spinlock);
+ spin_lock(&res->spinlock);
}
- spin_lock(&res->spinlock);
if (!list_empty(&res->purge)) {
mlog(0, "removing lockres %.*s:%p from purgelist, "
"master = %d\n", res->lockname.len, res->lockname.name,
res, master);
list_del_init(&res->purge);
- spin_unlock(&res->spinlock);
dlm_lockres_put(res);
dlm->purge_count--;
- } else
- spin_unlock(&res->spinlock);
+ }
- __dlm_unhash_lockres(res);
+ if (__dlm_lockres_unused(res))
+ __dlm_unhash_lockres(res);
+ else {
+ mlog(ML_ERROR, "found lockres %s:%.*s: in use after deref\n",
+ dlm->name, res->lockname.len, res->lockname.name);
+ __dlm_print_one_lock_resource(res);
+ BUG();
+ }
/* lockres is not in the hash now. drop the flag and wake up
* any processes waiting in dlm_get_lock_resource. */
if (!master) {
- spin_lock(&res->spinlock);
res->state &= ~DLM_LOCK_RES_DROPPING_REF;
spin_unlock(&res->spinlock);
wake_up(&res->wq);
- }
- return 0;
+ } else
+ spin_unlock(&res->spinlock);
}
static void dlm_run_purge_list(struct dlm_ctxt *dlm,
@@ -251,17 +236,7 @@ static void dlm_run_purge_list(struct dlm_ctxt *dlm,
lockres = list_entry(dlm->purge_list.next,
struct dlm_lock_resource, purge);
- /* Status of the lockres *might* change so double
- * check. If the lockres is unused, holding the dlm
- * spinlock will prevent people from getting and more
- * refs on it -- there's no need to keep the lockres
- * spinlock. */
spin_lock(&lockres->spinlock);
- unused = __dlm_lockres_unused(lockres);
- spin_unlock(&lockres->spinlock);
-
- if (!unused)
- continue;
purge_jiffies = lockres->last_used +
msecs_to_jiffies(DLM_PURGE_INTERVAL_MS);
@@ -273,15 +248,30 @@ static void dlm_run_purge_list(struct dlm_ctxt *dlm,
* in tail order, we can stop at the first
* unpurgable resource -- anyone added after
* him will have a greater last_used value */
+ spin_unlock(&lockres->spinlock);
break;
}
+ /* Status of the lockres *might* change so double
+ * check. If the lockres is unused, holding the dlm
+ * spinlock will prevent people from getting and more
+ * refs on it. */
+ unused = __dlm_lockres_unused(lockres);
+ if (!unused ||
+ (lockres->state & DLM_LOCK_RES_MIGRATING)) {
+ mlog(0, "lockres %s:%.*s: is in use or "
+ "being remastered\n", dlm->name,
+ lockres->lockname.len, lockres->lockname.name);
+ list_move_tail(&dlm->purge_list, &lockres->purge);
+ spin_unlock(&lockres->spinlock);
+ continue;
+ }
+
dlm_lockres_get(lockres);
/* This may drop and reacquire the dlm spinlock if it
* has to do migration. */
- if (dlm_purge_lockres(dlm, lockres))
- BUG();
+ dlm_purge_lockres(dlm, lockres);
dlm_lockres_put(lockres);
--
1.5.6.5
Sunil Mushran
2010-Jun-22 23:22 UTC
[Ocfs2-devel] [PATCH 1/1] ocfs2 fix o2dlm dlm run purgelist(bug 9094491) - rev3
Comments inlined. Getting there. Some more cleanups. On 06/22/2010 10:33 AM, Srinivas Eeda wrote:> There are two problems in dlm_run_purgelist > > 1. If a lockres is found to be in use, dlm_run_purgelist keeps trying to purge > the same lockres instead of trying the next lockres. > > 2. When a lockres is found unused, dlm_run_purgelist releases lockres spinlock > before setting DLM_LOCK_RES_DROPPING_REF and calls dlm_purge_lockres. > spinlock is reacquired but in this window lockres can get reused. This leads > to BUG. > > This patch modifies dlm_run_purgelist to skip lockres if it's in use and purge > next lockres. It also sets DLM_LOCK_RES_DROPPING_REF before releasing the > lockres spinlock protecting it from getting reused. > > Signed-off-by: Srinivas Eeda<srinivas.eeda at oracle.com> > --- > fs/ocfs2/dlm/dlmthread.c | 76 ++++++++++++++++++++-------------------------- > 1 files changed, 33 insertions(+), 43 deletions(-) > > diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c > index 11a6d1f..cb74689 100644 > --- a/fs/ocfs2/dlm/dlmthread.c > +++ b/fs/ocfs2/dlm/dlmthread.c > @@ -152,45 +152,26 @@ void dlm_lockres_calc_usage(struct dlm_ctxt *dlm, > spin_unlock(&dlm->spinlock); > } > > -static int dlm_purge_lockres(struct dlm_ctxt *dlm, > +static void dlm_purge_lockres(struct dlm_ctxt *dlm, > struct dlm_lock_resource *res) > { > int master; > int ret = 0; > > - spin_lock(&res->spinlock); > - if (!__dlm_lockres_unused(res)) { > - mlog(0, "%s:%.*s: tried to purge but not unused\n", > - dlm->name, res->lockname.len, res->lockname.name); > - __dlm_print_one_lock_resource(res); > - spin_unlock(&res->spinlock); > - BUG(); > - } > - > - if (res->state& DLM_LOCK_RES_MIGRATING) { > - mlog(0, "%s:%.*s: Delay dropref as this lockres is " > - "being remastered\n", dlm->name, res->lockname.len, > - res->lockname.name); > - /* Re-add the lockres to the end of the purge list */ > - if (!list_empty(&res->purge)) { > - list_del_init(&res->purge); > - list_add_tail(&res->purge,&dlm->purge_list); > - } > - spin_unlock(&res->spinlock); > - return 0; > - } > + assert_spin_locked(&dlm->spinlock); > + assert_spin_locked(&res->spinlock); > > master = (res->owner == dlm->node_num); > > if (!master) > res->state |= DLM_LOCK_RES_DROPPING_REF; > - spin_unlock(&res->spinlock); > > mlog(0, "purging lockres %.*s, master = %d\n", res->lockname.len, > res->lockname.name, master); > > if (!master) { > /* drop spinlock... retake below */ > + spin_unlock(&res->spinlock); > spin_unlock(&dlm->spinlock); > > spin_lock(&res->spinlock); >This can do with more cleanup. + assert_spin_locked(&dlm->spinlock); + assert_spin_locked(&res->spinlock); master = (res->owner == dlm->node_num); - if (!master) - res->state |= DLM_LOCK_RES_DROPPING_REF; - spin_unlock(&res->spinlock); mlog(0, "purging lockres %.*s, master = %d\n", res->lockname.len, res->lockname.name, master); if (!master) { + res->state |= DLM_LOCK_RES_DROPPING_REF; - /* drop spinlock... retake below */ + spin_unlock(&res->spinlock); spin_unlock(&dlm->spinlock); spin_lock(&res->spinlock);> @@ -208,31 +189,35 @@ static int dlm_purge_lockres(struct dlm_ctxt *dlm, > mlog(0, "%s:%.*s: dlm_deref_lockres returned %d\n", > dlm->name, res->lockname.len, res->lockname.name, ret); > spin_lock(&dlm->spinlock); > + spin_lock(&res->spinlock); > } > > - spin_lock(&res->spinlock); > if (!list_empty(&res->purge)) { > mlog(0, "removing lockres %.*s:%p from purgelist, " > "master = %d\n", res->lockname.len, res->lockname.name, > res, master); > list_del_init(&res->purge); > - spin_unlock(&res->spinlock); > dlm_lockres_put(res); > dlm->purge_count--; > - } else > - spin_unlock(&res->spinlock); > + } > > - __dlm_unhash_lockres(res); > + if (__dlm_lockres_unused(res)) > + __dlm_unhash_lockres(res); > + else { > + mlog(ML_ERROR, "found lockres %s:%.*s: in use after deref\n", > + dlm->name, res->lockname.len, res->lockname.name); > + __dlm_print_one_lock_resource(res); > + BUG(); > + } >Blocks that BUG should be separated if possible. Improves readability. + if (!__dlm_lockres_unused(res)) { + mlog(ML_ERROR, "found lockres %s:%.*s: in use after deref\n", + dlm->name, res->lockname.len, res->lockname.name); + __dlm_print_one_lock_resource(res); + BUG(); + } __dlm_unhash_lockres(res);> > /* lockres is not in the hash now. drop the flag and wake up > * any processes waiting in dlm_get_lock_resource. */ > if (!master) { > - spin_lock(&res->spinlock); > res->state&= ~DLM_LOCK_RES_DROPPING_REF; > spin_unlock(&res->spinlock); > wake_up(&res->wq); > - } > - return 0; > + } else > + spin_unlock(&res->spinlock); > } > > static void dlm_run_purge_list(struct dlm_ctxt *dlm, > @@ -251,17 +236,7 @@ static void dlm_run_purge_list(struct dlm_ctxt *dlm, > lockres = list_entry(dlm->purge_list.next, > struct dlm_lock_resource, purge); > > - /* Status of the lockres *might* change so double > - * check. If the lockres is unused, holding the dlm > - * spinlock will prevent people from getting and more > - * refs on it -- there's no need to keep the lockres > - * spinlock. */ > spin_lock(&lockres->spinlock); > - unused = __dlm_lockres_unused(lockres); > - spin_unlock(&lockres->spinlock); > - > - if (!unused) > - continue; > > purge_jiffies = lockres->last_used + > msecs_to_jiffies(DLM_PURGE_INTERVAL_MS); > @@ -273,15 +248,30 @@ static void dlm_run_purge_list(struct dlm_ctxt *dlm, > * in tail order, we can stop at the first > * unpurgable resource -- anyone added after > * him will have a greater last_used value */ > + spin_unlock(&lockres->spinlock); > break; > } > > + /* Status of the lockres *might* change so double > + * check. If the lockres is unused, holding the dlm > + * spinlock will prevent people from getting and more > + * refs on it. */ > + unused = __dlm_lockres_unused(lockres); > + if (!unused || > + (lockres->state& DLM_LOCK_RES_MIGRATING)) { > + mlog(0, "lockres %s:%.*s: is in use or " > + "being remastered\n", dlm->name, > + lockres->lockname.len, lockres->lockname.name); > + list_move_tail(&dlm->purge_list,&lockres->purge); > + spin_unlock(&lockres->spinlock); > + continue; > + } > + > dlm_lockres_get(lockres); > > /* This may drop and reacquire the dlm spinlock if it > * has to do migration. */ > - if (dlm_purge_lockres(dlm, lockres)) > - BUG(); > + dlm_purge_lockres(dlm, lockres); > > dlm_lockres_put(lockres); > >This comment is dated. We don't migrate in purge_lockres. - /* This may drop and reacquire the dlm spinlock if it - * has to do migration. */ - if (dlm_purge_lockres(dlm, lockres)) - BUG(); + dlm_purge_lockres(dlm, lockres); dlm_lockres_put(lockres);
Srinivas Eeda
2010-Jun-23 05:48 UTC
[Ocfs2-devel] [PATCH 1/1] ocfs2 fix o2dlm dlm run purgelist(bug 9094491) - rev3
There are two problems in dlm_run_purgelist
1. If a lockres is found to be in use, dlm_run_purgelist keeps trying to purge
the same lockres instead of trying the next lockres.
2. When a lockres is found unused, dlm_run_purgelist releases lockres spinlock
before setting DLM_LOCK_RES_DROPPING_REF and calls dlm_purge_lockres.
spinlock is reacquired but in this window lockres can get reused. This leads
to BUG.
This patch modifies dlm_run_purgelist to skip lockres if it's in use and
purge
next lockres. It also sets DLM_LOCK_RES_DROPPING_REF before releasing the
lockres spinlock protecting it from getting reused.
Signed-off-by: Srinivas Eeda <srinivas.eeda at oracle.com>
---
fs/ocfs2/dlm/dlmthread.c | 79 +++++++++++++++++++--------------------------
1 files changed, 33 insertions(+), 46 deletions(-)
diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c
index 11a6d1f..6822f9a 100644
--- a/fs/ocfs2/dlm/dlmthread.c
+++ b/fs/ocfs2/dlm/dlmthread.c
@@ -152,45 +152,25 @@ void dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
spin_unlock(&dlm->spinlock);
}
-static int dlm_purge_lockres(struct dlm_ctxt *dlm,
+static void dlm_purge_lockres(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res)
{
int master;
int ret = 0;
- spin_lock(&res->spinlock);
- if (!__dlm_lockres_unused(res)) {
- mlog(0, "%s:%.*s: tried to purge but not unused\n",
- dlm->name, res->lockname.len, res->lockname.name);
- __dlm_print_one_lock_resource(res);
- spin_unlock(&res->spinlock);
- BUG();
- }
-
- if (res->state & DLM_LOCK_RES_MIGRATING) {
- mlog(0, "%s:%.*s: Delay dropref as this lockres is "
- "being remastered\n", dlm->name, res->lockname.len,
- res->lockname.name);
- /* Re-add the lockres to the end of the purge list */
- if (!list_empty(&res->purge)) {
- list_del_init(&res->purge);
- list_add_tail(&res->purge, &dlm->purge_list);
- }
- spin_unlock(&res->spinlock);
- return 0;
- }
+ assert_spin_locked(&dlm->spinlock);
+ assert_spin_locked(&res->spinlock);
master = (res->owner == dlm->node_num);
- if (!master)
- res->state |= DLM_LOCK_RES_DROPPING_REF;
- spin_unlock(&res->spinlock);
mlog(0, "purging lockres %.*s, master = %d\n", res->lockname.len,
res->lockname.name, master);
if (!master) {
+ res->state |= DLM_LOCK_RES_DROPPING_REF;
/* drop spinlock... retake below */
+ spin_unlock(&res->spinlock);
spin_unlock(&dlm->spinlock);
spin_lock(&res->spinlock);
@@ -208,31 +188,35 @@ static int dlm_purge_lockres(struct dlm_ctxt *dlm,
mlog(0, "%s:%.*s: dlm_deref_lockres returned %d\n",
dlm->name, res->lockname.len, res->lockname.name, ret);
spin_lock(&dlm->spinlock);
+ spin_lock(&res->spinlock);
}
- spin_lock(&res->spinlock);
if (!list_empty(&res->purge)) {
mlog(0, "removing lockres %.*s:%p from purgelist, "
"master = %d\n", res->lockname.len, res->lockname.name,
res, master);
list_del_init(&res->purge);
- spin_unlock(&res->spinlock);
dlm_lockres_put(res);
dlm->purge_count--;
- } else
- spin_unlock(&res->spinlock);
+ }
+
+ if (!__dlm_lockres_unused) {
+ mlog(ML_ERROR, "found lockres %s:%.*s: in use after deref\n",
+ dlm->name, res->lockname.len, res->lockname.name);
+ __dlm_print_one_lock_resource(res);
+ BUG();
+ }
__dlm_unhash_lockres(res);
/* lockres is not in the hash now. drop the flag and wake up
* any processes waiting in dlm_get_lock_resource. */
if (!master) {
- spin_lock(&res->spinlock);
res->state &= ~DLM_LOCK_RES_DROPPING_REF;
spin_unlock(&res->spinlock);
wake_up(&res->wq);
- }
- return 0;
+ } else
+ spin_unlock(&res->spinlock);
}
static void dlm_run_purge_list(struct dlm_ctxt *dlm,
@@ -251,17 +235,7 @@ static void dlm_run_purge_list(struct dlm_ctxt *dlm,
lockres = list_entry(dlm->purge_list.next,
struct dlm_lock_resource, purge);
- /* Status of the lockres *might* change so double
- * check. If the lockres is unused, holding the dlm
- * spinlock will prevent people from getting and more
- * refs on it -- there's no need to keep the lockres
- * spinlock. */
spin_lock(&lockres->spinlock);
- unused = __dlm_lockres_unused(lockres);
- spin_unlock(&lockres->spinlock);
-
- if (!unused)
- continue;
purge_jiffies = lockres->last_used +
msecs_to_jiffies(DLM_PURGE_INTERVAL_MS);
@@ -273,15 +247,28 @@ static void dlm_run_purge_list(struct dlm_ctxt *dlm,
* in tail order, we can stop at the first
* unpurgable resource -- anyone added after
* him will have a greater last_used value */
+ spin_unlock(&lockres->spinlock);
break;
}
+ /* Status of the lockres *might* change so double
+ * check. If the lockres is unused, holding the dlm
+ * spinlock will prevent people from getting and more
+ * refs on it. */
+ unused = __dlm_lockres_unused(lockres);
+ if (!unused ||
+ (lockres->state & DLM_LOCK_RES_MIGRATING)) {
+ mlog(0, "lockres %s:%.*s: is in use or "
+ "being remastered\n", dlm->name,
+ lockres->lockname.len, lockres->lockname.name);
+ list_move_tail(&dlm->purge_list, &lockres->purge);
+ spin_unlock(&lockres->spinlock);
+ continue;
+ }
+
dlm_lockres_get(lockres);
- /* This may drop and reacquire the dlm spinlock if it
- * has to do migration. */
- if (dlm_purge_lockres(dlm, lockres))
- BUG();
+ dlm_purge_lockres(dlm, lockres);
dlm_lockres_put(lockres);
--
1.5.6.5
Joel Becker
2010-Jul-12 18:21 UTC
[Ocfs2-devel] [PATCH 1/1] ocfs2 fix o2dlm dlm run purgelist(bug 9094491) - rev3
On Tue, Jun 22, 2010 at 10:48:28PM -0700, Srinivas Eeda wrote:> + if (!__dlm_lockres_unused) { > + mlog(ML_ERROR, "found lockres %s:%.*s: in use after deref\n", > + dlm->name, res->lockname.len, res->lockname.name); > + __dlm_print_one_lock_resource(res); > + BUG(); > + }/build/jlbec/linux-2.6/working/fs/ocfs2/dlm/dlmthread.c: In function ?dlm_purge_lockres?: /build/jlbec/linux-2.6/working/fs/ocfs2/dlm/dlmthread.c:203: warning: the address of ?__dlm_lockres_unused? will always evaluate as ?true? Was this even tested? I'm leaving this patch out of 'fixes' until corrected and tested. Joel -- "Reader, suppose you were and idiot. And suppose you were a member of Congress. But I repeat myself." - Mark Twain Joel Becker Consulting Software Developer Oracle E-mail: joel.becker at oracle.com Phone: (650) 506-8127
Srinivas Eeda
2010-Jul-12 22:16 UTC
[Ocfs2-devel] [PATCH 1/1] ocfs2 fix o2dlm dlm run purgelist(bug 9094491) - rev3
There are two problems in dlm_run_purgelist
1. If a lockres is found to be in use, dlm_run_purgelist keeps trying to purge
the same lockres instead of trying the next lockres.
2. When a lockres is found unused, dlm_run_purgelist releases lockres spinlock
before setting DLM_LOCK_RES_DROPPING_REF and calls dlm_purge_lockres.
spinlock is reacquired but in this window lockres can get reused. This leads
to BUG.
This patch modifies dlm_run_purgelist to skip lockres if it's in use and
purge
next lockres. It also sets DLM_LOCK_RES_DROPPING_REF before releasing the
lockres spinlock protecting it from getting reused.
Signed-off-by: Srinivas Eeda <srinivas.eeda at oracle.com>
Signed-off-by: Sunil Mushran<sunil.mushran at oracle.com>
---
fs/ocfs2/dlm/dlmthread.c | 79 +++++++++++++++++++--------------------------
1 files changed, 33 insertions(+), 46 deletions(-)
diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c
index 11a6d1f..76ab4aa 100644
--- a/fs/ocfs2/dlm/dlmthread.c
+++ b/fs/ocfs2/dlm/dlmthread.c
@@ -152,45 +152,25 @@ void dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
spin_unlock(&dlm->spinlock);
}
-static int dlm_purge_lockres(struct dlm_ctxt *dlm,
+static void dlm_purge_lockres(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res)
{
int master;
int ret = 0;
- spin_lock(&res->spinlock);
- if (!__dlm_lockres_unused(res)) {
- mlog(0, "%s:%.*s: tried to purge but not unused\n",
- dlm->name, res->lockname.len, res->lockname.name);
- __dlm_print_one_lock_resource(res);
- spin_unlock(&res->spinlock);
- BUG();
- }
-
- if (res->state & DLM_LOCK_RES_MIGRATING) {
- mlog(0, "%s:%.*s: Delay dropref as this lockres is "
- "being remastered\n", dlm->name, res->lockname.len,
- res->lockname.name);
- /* Re-add the lockres to the end of the purge list */
- if (!list_empty(&res->purge)) {
- list_del_init(&res->purge);
- list_add_tail(&res->purge, &dlm->purge_list);
- }
- spin_unlock(&res->spinlock);
- return 0;
- }
+ assert_spin_locked(&dlm->spinlock);
+ assert_spin_locked(&res->spinlock);
master = (res->owner == dlm->node_num);
- if (!master)
- res->state |= DLM_LOCK_RES_DROPPING_REF;
- spin_unlock(&res->spinlock);
mlog(0, "purging lockres %.*s, master = %d\n", res->lockname.len,
res->lockname.name, master);
if (!master) {
+ res->state |= DLM_LOCK_RES_DROPPING_REF;
/* drop spinlock... retake below */
+ spin_unlock(&res->spinlock);
spin_unlock(&dlm->spinlock);
spin_lock(&res->spinlock);
@@ -208,31 +188,35 @@ static int dlm_purge_lockres(struct dlm_ctxt *dlm,
mlog(0, "%s:%.*s: dlm_deref_lockres returned %d\n",
dlm->name, res->lockname.len, res->lockname.name, ret);
spin_lock(&dlm->spinlock);
+ spin_lock(&res->spinlock);
}
- spin_lock(&res->spinlock);
if (!list_empty(&res->purge)) {
mlog(0, "removing lockres %.*s:%p from purgelist, "
"master = %d\n", res->lockname.len, res->lockname.name,
res, master);
list_del_init(&res->purge);
- spin_unlock(&res->spinlock);
dlm_lockres_put(res);
dlm->purge_count--;
- } else
- spin_unlock(&res->spinlock);
+ }
+
+ if (!__dlm_lockres_unused(res)) {
+ mlog(ML_ERROR, "found lockres %s:%.*s: in use after deref\n",
+ dlm->name, res->lockname.len, res->lockname.name);
+ __dlm_print_one_lock_resource(res);
+ BUG();
+ }
__dlm_unhash_lockres(res);
/* lockres is not in the hash now. drop the flag and wake up
* any processes waiting in dlm_get_lock_resource. */
if (!master) {
- spin_lock(&res->spinlock);
res->state &= ~DLM_LOCK_RES_DROPPING_REF;
spin_unlock(&res->spinlock);
wake_up(&res->wq);
- }
- return 0;
+ } else
+ spin_unlock(&res->spinlock);
}
static void dlm_run_purge_list(struct dlm_ctxt *dlm,
@@ -251,17 +235,7 @@ static void dlm_run_purge_list(struct dlm_ctxt *dlm,
lockres = list_entry(dlm->purge_list.next,
struct dlm_lock_resource, purge);
- /* Status of the lockres *might* change so double
- * check. If the lockres is unused, holding the dlm
- * spinlock will prevent people from getting and more
- * refs on it -- there's no need to keep the lockres
- * spinlock. */
spin_lock(&lockres->spinlock);
- unused = __dlm_lockres_unused(lockres);
- spin_unlock(&lockres->spinlock);
-
- if (!unused)
- continue;
purge_jiffies = lockres->last_used +
msecs_to_jiffies(DLM_PURGE_INTERVAL_MS);
@@ -273,15 +247,28 @@ static void dlm_run_purge_list(struct dlm_ctxt *dlm,
* in tail order, we can stop at the first
* unpurgable resource -- anyone added after
* him will have a greater last_used value */
+ spin_unlock(&lockres->spinlock);
break;
}
+ /* Status of the lockres *might* change so double
+ * check. If the lockres is unused, holding the dlm
+ * spinlock will prevent people from getting and more
+ * refs on it. */
+ unused = __dlm_lockres_unused(lockres);
+ if (!unused ||
+ (lockres->state & DLM_LOCK_RES_MIGRATING)) {
+ mlog(0, "lockres %s:%.*s: is in use or "
+ "being remastered\n", dlm->name,
+ lockres->lockname.len, lockres->lockname.name);
+ list_move_tail(&dlm->purge_list, &lockres->purge);
+ spin_unlock(&lockres->spinlock);
+ continue;
+ }
+
dlm_lockres_get(lockres);
- /* This may drop and reacquire the dlm spinlock if it
- * has to do migration. */
- if (dlm_purge_lockres(dlm, lockres))
- BUG();
+ dlm_purge_lockres(dlm, lockres);
dlm_lockres_put(lockres);
--
1.5.6.5