Currently the exclusive lock is acquired only if the mapping is
writable, i.e. an image HEAD mapped in rw mode. This means that we
don't acquire the lock for executing a read from a snapshot or an image
HEAD mapped in ro mode, even if lock_on_read is set. This is somewhat
weird and inconsistent with "no automatic exclusive lock transfers"
mode, where the lock is acquired unconditionally.
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
---
drivers/block/rbd.c | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index b859ce00ee1e..bcc43fb8a9b3 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -478,13 +478,6 @@ static int minor_to_rbd_dev_id(int minor)
return minor >> RBD_SINGLE_MAJOR_PART_SHIFT;
}
-static bool rbd_is_lock_supported(struct rbd_device *rbd_dev)
-{
- return (rbd_dev->header.features & RBD_FEATURE_EXCLUSIVE_LOCK) &&
- rbd_dev->spec->snap_id == CEPH_NOSNAP &&
- !rbd_dev->mapping.read_only;
-}
-
static bool __rbd_is_lock_owner(struct rbd_device *rbd_dev)
{
return rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED ||
@@ -4052,10 +4045,6 @@ static void rbd_queue_workfn(struct work_struct *work)
if (op_type != OBJ_OP_READ) {
snapc = rbd_dev->header.snapc;
ceph_get_snap_context(snapc);
- must_be_locked = rbd_is_lock_supported(rbd_dev);
- } else {
- must_be_locked = rbd_dev->opts->lock_on_read &&
- rbd_is_lock_supported(rbd_dev);
}
up_read(&rbd_dev->header_rwsem);
@@ -4066,6 +4055,9 @@ static void rbd_queue_workfn(struct work_struct *work)
goto err_rq;
}
+ must_be_locked =
+ (rbd_dev->header.features & RBD_FEATURE_EXCLUSIVE_LOCK) &&
+ (op_type != OBJ_OP_READ || rbd_dev->opts->lock_on_read);
if (must_be_locked) {
down_read(&rbd_dev->lock_rwsem);
if (rbd_dev->lock_state != RBD_LOCK_STATE_LOCKED &&
--
2.4.3
--
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