FS-Cache: Permit cache retrieval ops to be interrupted in the initial wait phase

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

diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 250dfd3..e6f2e61 100644 (file)
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -295,8 +295,20 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
        if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
                _debug(">>> WT");
                fscache_stat(&fscache_n_retrieval_op_waits);
-               wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
-                           fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+               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");
        }
 
@@ -313,6 +325,7 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
                fscache_stat_d(&fscache_n_cop_read_or_alloc_page);
        }
 
+error:
        if (ret == -ENOMEM)
                fscache_stat(&fscache_n_retrievals_nomem);
        else if (ret == -ERESTARTSYS)
@@ -412,8 +425,20 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
        if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
                _debug(">>> WT");
                fscache_stat(&fscache_n_retrieval_op_waits);
-               wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
-                           fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+               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");
        }
 
@@ -430,6 +455,7 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
                fscache_stat_d(&fscache_n_cop_read_or_alloc_pages);
        }
 
+error:
        if (ret == -ENOMEM)
                fscache_stat(&fscache_n_retrievals_nomem);
        else if (ret == -ERESTARTSYS)
@@ -505,8 +531,20 @@ int __fscache_alloc_page(struct fscache_cookie *cookie,
        if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
                _debug(">>> WT");
                fscache_stat(&fscache_n_alloc_op_waits);
-               wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
-                           fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+               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");
        }
 
@@ -515,7 +553,10 @@ int __fscache_alloc_page(struct fscache_cookie *cookie,
        ret = object->cache->ops->allocate_page(op, page, gfp);
        fscache_stat_d(&fscache_n_cop_allocate_page);
 
-       if (ret < 0)
+error:
+       if (ret == -ERESTARTSYS)
+               fscache_stat(&fscache_n_allocs_intr);
+       else if (ret < 0)
                fscache_stat(&fscache_n_allocs_nobufs);
        else
                fscache_stat(&fscache_n_allocs_ok);