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authorDavid Howells2009-11-19 19:11:45 +0100
committerDavid Howells2009-11-19 19:11:45 +0100
commit60d543ca724be155c2b6166e36a00c80b21bd810 (patch)
tree90ec6edd77ddb7666dbf7069aa2e001f155cea49 /fs/fscache/page.c
parentFS-Cache: Make sure FSCACHE_COOKIE_LOOKING_UP cleared on lookup failure (diff)
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FS-Cache: Start processing an object's operations on that object's death
Start processing an object's operations when that object moves into the DYING state as the object cannot be destroyed until all its outstanding operations have completed. Furthermore, make sure that read and allocation operations handle being woken up on a dead object. Such events are recorded in the Allocs.abt and Retrvls.abt statistics as viewable through /proc/fs/fscache/stats. The code for waiting for object activation for the read and allocation operations is also extracted into its own function as it is much the same in all cases, differing only in the stats incremented. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/fscache/page.c')
-rw-r--r--fs/fscache/page.c112
1 files changed, 55 insertions, 57 deletions
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index fc76798bd968..c598ea4c4e7d 100644
--- 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);