FS-Cache: When submitting an op, cancel it if the target object is dying

[firefly-linux-kernel-4.4.55.git] / fs / fscache / operation.c

diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c
index 68ead84826178244a5141d2282f8192d63c47d4c..dec6defe3be30941bbd0171bfba560e42bd78919 100644 (file)
--- a/fs/fscache/operation.c
+++ b/fs/fscache/operation.c
@@ -120,6 +120,8 @@ static void fscache_report_unexpected_submission(struct fscache_object *object,
 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);
@@ -132,8 +134,19 @@ int fscache_submit_exclusive_op(struct fscache_object *object,
        ASSERTCMP(object->n_ops, >=, object->n_exclusive);
        ASSERT(list_empty(&op->pend_link));
 
+       ostate = object->state;
+       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++;
                object->n_exclusive++;  /* reads and writes must wait */
@@ -155,7 +168,7 @@ int fscache_submit_exclusive_op(struct fscache_object *object,
                /* 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 */
@@ -164,11 +177,9 @@ int fscache_submit_exclusive_op(struct fscache_object *object,
                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);
@@ -187,6 +198,7 @@ int fscache_submit_op(struct fscache_object *object,
                      struct fscache_operation *op)
 {
        const struct fscache_state *ostate;
+       unsigned long flags;
        int ret;
 
        _enter("{OBJ%x OP%x},{%u}",
@@ -204,7 +216,15 @@ int fscache_submit_op(struct fscache_object *object,
        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++;
 
@@ -222,25 +242,18 @@ int fscache_submit_op(struct fscache_object *object,
                        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;
-       } 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)) {
+       } else {
                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);