FS-Cache: Start processing an object's operations on that object's death

[safe/jmp/linux-2.6] / fs / fscache / page.c

diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index fc76798..c598ea4 100644 (file)
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -314,6 +314,43 @@ static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
 }
 
 /*
+ * wait for an object to become active (or dead)
+ */
+static int fscache_wait_for_retrieval_activation(struct fscache_object *object,
+                                                struct fscache_retrieval *op,
+                                                atomic_t *stat_op_waits,
+                                                atomic_t *stat_object_dead)
+{
+       int ret;
+
+       if (!test_bit(FSCACHE_OP_WAITING, &op->op.flags))
+               goto check_if_dead;
+
+       _debug(">>> WT");
+       fscache_stat(stat_op_waits);
+       if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
+                       fscache_wait_bit_interruptible,
+                       TASK_INTERRUPTIBLE) < 0) {
+               ret = fscache_cancel_op(&op->op);
+               if (ret == 0)
+                       return -ERESTARTSYS;
+
+               /* it's been removed from the pending queue by another party,
+                * so we should get to run shortly */
+               wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
+                           fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+       }
+       _debug("<<< GO");
+
+check_if_dead:
+       if (unlikely(fscache_object_is_dead(object))) {
+               fscache_stat(stat_object_dead);
+               return -ENOBUFS;
+       }
+       return 0;
+}
+
+/*
  * read a page from the cache or allocate a block in which to store it
  * - we return:
  *   -ENOMEM   - out of memory, nothing done
@@ -376,25 +413,12 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
 
        /* we wait for the operation to become active, and then process it
         * *here*, in this thread, and not in the thread pool */
-       if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
-               _debug(">>> WT");
-               fscache_stat(&fscache_n_retrieval_op_waits);
-               if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
-                               fscache_wait_bit_interruptible,
-                               TASK_INTERRUPTIBLE) < 0) {
-                       ret = fscache_cancel_op(&op->op);
-                       if (ret == 0) {
-                               ret = -ERESTARTSYS;
-                               goto error;
-                       }
-
-                       /* it's been removed from the pending queue by another
-                        * party, so we should get to run shortly */
-                       wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
-                                   fscache_wait_bit, TASK_UNINTERRUPTIBLE);
-               }
-               _debug("<<< GO");
-       }
+       ret = fscache_wait_for_retrieval_activation(
+               object, op,
+               __fscache_stat(&fscache_n_retrieval_op_waits),
+               __fscache_stat(&fscache_n_retrievals_object_dead));
+       if (ret < 0)
+               goto error;
 
        /* ask the cache to honour the operation */
        if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
@@ -506,25 +530,12 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
 
        /* we wait for the operation to become active, and then process it
         * *here*, in this thread, and not in the thread pool */
-       if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
-               _debug(">>> WT");
-               fscache_stat(&fscache_n_retrieval_op_waits);
-               if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
-                               fscache_wait_bit_interruptible,
-                               TASK_INTERRUPTIBLE) < 0) {
-                       ret = fscache_cancel_op(&op->op);
-                       if (ret == 0) {
-                               ret = -ERESTARTSYS;
-                               goto error;
-                       }
-
-                       /* it's been removed from the pending queue by another
-                        * party, so we should get to run shortly */
-                       wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
-                                   fscache_wait_bit, TASK_UNINTERRUPTIBLE);
-               }
-               _debug("<<< GO");
-       }
+       ret = fscache_wait_for_retrieval_activation(
+               object, op,
+               __fscache_stat(&fscache_n_retrieval_op_waits),
+               __fscache_stat(&fscache_n_retrievals_object_dead));
+       if (ret < 0)
+               goto error;
 
        /* ask the cache to honour the operation */
        if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
@@ -612,25 +623,12 @@ int __fscache_alloc_page(struct fscache_cookie *cookie,
 
        fscache_stat(&fscache_n_alloc_ops);
 
-       if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
-               _debug(">>> WT");
-               fscache_stat(&fscache_n_alloc_op_waits);
-               if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
-                               fscache_wait_bit_interruptible,
-                               TASK_INTERRUPTIBLE) < 0) {
-                       ret = fscache_cancel_op(&op->op);
-                       if (ret == 0) {
-                               ret = -ERESTARTSYS;
-                               goto error;
-                       }
-
-                       /* it's been removed from the pending queue by another
-                        * party, so we should get to run shortly */
-                       wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
-                                   fscache_wait_bit, TASK_UNINTERRUPTIBLE);
-               }
-               _debug("<<< GO");
-       }
+       ret = fscache_wait_for_retrieval_activation(
+               object, op,
+               __fscache_stat(&fscache_n_alloc_op_waits),
+               __fscache_stat(&fscache_n_allocs_object_dead));
+       if (ret < 0)
+               goto error;
 
        /* ask the cache to honour the operation */
        fscache_stat(&fscache_n_cop_allocate_page);