[PATCH 16/26] staging/lustre/lov: avoid subobj's coh_parent race

Peng Tao
2013-11-14T16:48:15Z

From: Bobi Jam <bobijam.xu@intel.com>

* during a file lov object initialization, we need protect the access
and change of its subobj->coh_parent, since it could be another
layout change race there, which makes an unreferenced lovsub obj in
the site object hash table.

* dump lovsub objects in the site if the lovsub device reference > 0
during its finalization phase.

Lustre-change: http://review.whamcloud.com/6105
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-1480
Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
---
drivers/staging/lustre/lustre/lov/lov_object.c | 12 ++++++++----
drivers/staging/lustre/lustre/lov/lovsub_dev.c | 4 ++++
2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/lustre/lustre/lov/lov_object.c b/drivers/staging/lustre/lustre/lov/lov_object.c
index df8b5b5..368014a 100644
--- a/drivers/staging/lustre/lustre/lov/lov_object.c
+++ b/drivers/staging/lustre/lustre/lov/lov_object.c
@@ -122,13 +122,13 @@ static struct cl_object *lov_sub_find(const struct lu_env *env,
}

static int lov_init_sub(const struct lu_env *env, struct lov_object *lov,
- struct cl_object *stripe,
- struct lov_layout_raid0 *r0, int idx)
+ struct cl_object *stripe, struct lov_layout_raid0 *r0,
+ int idx)
{
struct cl_object_header *hdr;
struct cl_object_header *subhdr;
struct cl_object_header *parent;
- struct lov_oinfo *oinfo;
+ struct lov_oinfo *oinfo;
int result;

if (OBD_FAIL_CHECK(OBD_FAIL_LOV_INIT)) {
@@ -144,7 +144,6 @@ static int lov_init_sub(const struct lu_env *env, struct lov_object *lov,

hdr = cl_object_header(lov2cl(lov));
subhdr = cl_object_header(stripe);
- parent = subhdr->coh_parent;

oinfo = lov->lo_lsm->lsm_oinfo[idx];
CDEBUG(D_INODE, DFID"@%p[%d] -> "DFID"@%p: ostid: "DOSTID
@@ -153,8 +152,12 @@ static int lov_init_sub(const struct lu_env *env, struct lov_object *lov,
PFID(&hdr->coh_lu.loh_fid), hdr, POSTID(&oinfo->loi_oi),
oinfo->loi_ost_idx, oinfo->loi_ost_gen);

+ /* reuse ->coh_attr_guard to protect coh_parent change */
+ spin_lock(&subhdr->coh_attr_guard);
+ parent = subhdr->coh_parent;
if (parent == NULL) {
subhdr->coh_parent = hdr;
+ spin_unlock(&subhdr->coh_attr_guard);
subhdr->coh_nesting = hdr->coh_nesting + 1;
lu_object_ref_add(&stripe->co_lu, "lov-parent", lov);
r0->lo_sub[idx] = cl2lovsub(stripe);
@@ -166,6 +169,7 @@ static int lov_init_sub(const struct lu_env *env, struct lov_object *lov,
struct lov_object *old_lov;
unsigned int mask = D_INODE;

+ spin_unlock(&subhdr->coh_attr_guard);
old_obj = lu_object_locate(&parent->coh_lu, &lov_device_type);
LASSERT(old_obj != NULL);
old_lov = cl2lov(lu2cl(old_obj));
diff --git a/drivers/staging/lustre/lustre/lov/lovsub_dev.c b/drivers/staging/lustre/lustre/lov/lovsub_dev.c
index 998ea1c..926c35a 100644
--- a/drivers/staging/lustre/lustre/lov/lovsub_dev.c
+++ b/drivers/staging/lustre/lustre/lov/lovsub_dev.c
@@ -131,6 +131,10 @@ static struct lu_device *lovsub_device_free(const struct lu_env *env,
struct lovsub_device *lsd = lu2lovsub_dev(d);
struct lu_device *next = cl2lu_dev(lsd->acid_next);

+ if (atomic_read(&d->ld_ref) && d->ld_site) {
+ LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, D_ERROR, NULL);
+ lu_site_print(env, d->ld_site, &msgdata, lu_cdebug_printer);
+ }
cl_device_fini(lu2cl_dev(d));
OBD_FREE_PTR(lsd);
return next;
--
1.7.9.5