When submitting an operation, prefer to cancel the operation immediately
rather than queuing it for later processing if the object is marked as dying
(ie. the object state machine has reached the KILL_OBJECT state).
Whilst we're at it, change the series of related test_bit() calls into a
READ_ONCE() and bitwise-AND operators to reduce the number of load
instructions (test_bit() has a volatile address).
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jeff.layton@primarydata.com>
int fscache_submit_exclusive_op(struct fscache_object *object,
struct fscache_operation *op)
{
int fscache_submit_exclusive_op(struct fscache_object *object,
struct fscache_operation *op)
{
+ const struct fscache_state *ostate;
+ unsigned long flags;
int ret;
_enter("{OBJ%x OP%x},", object->debug_id, op->debug_id);
int ret;
_enter("{OBJ%x OP%x},", object->debug_id, op->debug_id);
ASSERTCMP(object->n_ops, >=, object->n_exclusive);
ASSERT(list_empty(&op->pend_link));
ASSERTCMP(object->n_ops, >=, object->n_exclusive);
ASSERT(list_empty(&op->pend_link));
+ ostate = object->state;
+ smp_rmb();
+
op->state = FSCACHE_OP_ST_PENDING;
op->state = FSCACHE_OP_ST_PENDING;
- if (fscache_object_is_active(object)) {
+ flags = READ_ONCE(object->flags);
+ if (unlikely(!(flags & BIT(FSCACHE_OBJECT_IS_LIVE)))) {
+ fscache_stat(&fscache_n_op_rejected);
+ op->state = FSCACHE_OP_ST_CANCELLED;
+ ret = -ENOBUFS;
+ } else if (unlikely(fscache_cache_is_broken(object))) {
+ op->state = FSCACHE_OP_ST_CANCELLED;
+ ret = -EIO;
+ } else if (flags & BIT(FSCACHE_OBJECT_IS_AVAILABLE)) {
op->object = object;
object->n_ops++;
object->n_exclusive++; /* reads and writes must wait */
op->object = object;
object->n_ops++;
object->n_exclusive++; /* reads and writes must wait */
/* need to issue a new write op after this */
clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
ret = 0;
/* need to issue a new write op after this */
clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
ret = 0;
- } else if (test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
+ } else if (flags & BIT(FSCACHE_OBJECT_IS_LOOKED_UP)) {
op->object = object;
object->n_ops++;
object->n_exclusive++; /* reads and writes must wait */
op->object = object;
object->n_ops++;
object->n_exclusive++; /* reads and writes must wait */
fscache_stat(&fscache_n_op_pend);
ret = 0;
} else {
fscache_stat(&fscache_n_op_pend);
ret = 0;
} else {
- /* If we're in any other state, there must have been an I/O
- * error of some nature.
- */
- ASSERT(test_bit(FSCACHE_IOERROR, &object->cache->flags));
- ret = -EIO;
+ fscache_report_unexpected_submission(object, op, ostate);
+ op->state = FSCACHE_OP_ST_CANCELLED;
+ ret = -ENOBUFS;
}
spin_unlock(&object->lock);
}
spin_unlock(&object->lock);
struct fscache_operation *op)
{
const struct fscache_state *ostate;
struct fscache_operation *op)
{
const struct fscache_state *ostate;
int ret;
_enter("{OBJ%x OP%x},{%u}",
int ret;
_enter("{OBJ%x OP%x},{%u}",
smp_rmb();
op->state = FSCACHE_OP_ST_PENDING;
smp_rmb();
op->state = FSCACHE_OP_ST_PENDING;
- if (fscache_object_is_active(object)) {
+ flags = READ_ONCE(object->flags);
+ if (unlikely(!(flags & BIT(FSCACHE_OBJECT_IS_LIVE)))) {
+ fscache_stat(&fscache_n_op_rejected);
+ op->state = FSCACHE_OP_ST_CANCELLED;
+ ret = -ENOBUFS;
+ } else if (unlikely(fscache_cache_is_broken(object))) {
+ op->state = FSCACHE_OP_ST_CANCELLED;
+ ret = -EIO;
+ } else if (flags & BIT(FSCACHE_OBJECT_IS_AVAILABLE)) {
op->object = object;
object->n_ops++;
op->object = object;
object->n_ops++;
fscache_run_op(object, op);
}
ret = 0;
fscache_run_op(object, op);
}
ret = 0;
- } else if (test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
+ } else if (flags & BIT(FSCACHE_OBJECT_IS_LOOKED_UP)) {
op->object = object;
object->n_ops++;
atomic_inc(&op->usage);
list_add_tail(&op->pend_link, &object->pending_ops);
fscache_stat(&fscache_n_op_pend);
ret = 0;
op->object = object;
object->n_ops++;
atomic_inc(&op->usage);
list_add_tail(&op->pend_link, &object->pending_ops);
fscache_stat(&fscache_n_op_pend);
ret = 0;
- } else if (fscache_object_is_dying(object)) {
- fscache_stat(&fscache_n_op_rejected);
- op->state = FSCACHE_OP_ST_CANCELLED;
- ret = -ENOBUFS;
- } else if (!test_bit(FSCACHE_IOERROR, &object->cache->flags)) {
fscache_report_unexpected_submission(object, op, ostate);
ASSERT(!fscache_object_is_active(object));
op->state = FSCACHE_OP_ST_CANCELLED;
ret = -ENOBUFS;
fscache_report_unexpected_submission(object, op, ostate);
ASSERT(!fscache_object_is_active(object));
op->state = FSCACHE_OP_ST_CANCELLED;
ret = -ENOBUFS;
- } else {
- op->state = FSCACHE_OP_ST_CANCELLED;
- ret = -ENOBUFS;
}
spin_unlock(&object->lock);
}
spin_unlock(&object->lock);
return test_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
}
return test_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
}
+static inline bool fscache_cache_is_broken(struct fscache_object *object)
+{
+ return test_bit(FSCACHE_IOERROR, &object->cache->flags);
+}
+
static inline bool fscache_object_is_active(struct fscache_object *object)
{
return fscache_object_is_available(object) &&
fscache_object_is_live(object) &&
static inline bool fscache_object_is_active(struct fscache_object *object)
{
return fscache_object_is_available(object) &&
fscache_object_is_live(object) &&
- !test_bit(FSCACHE_IOERROR, &object->cache->flags);
+ !fscache_cache_is_broken(object);
}
static inline bool fscache_object_is_dead(struct fscache_object *object)
{
return fscache_object_is_dying(object) &&
}
static inline bool fscache_object_is_dead(struct fscache_object *object)
{
return fscache_object_is_dying(object) &&
- test_bit(FSCACHE_IOERROR, &object->cache->flags);
+ fscache_cache_is_broken(object);