Make fscache_relinquish_cookie() log a warning and wait if there are any
outstanding reads left on the cookie it was given.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---
fs/fscache/cookie.c | 18 ++++++++++++++----
fs/fscache/operation.c | 10 ++++++++--
include/linux/fscache-cache.h | 1 +
3 files changed, 23 insertions(+), 6 deletions(-)
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 0666996..66be9ec 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -442,22 +442,32 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire)
event = retire ? FSCACHE_OBJECT_EV_RETIRE : FSCACHE_OBJECT_EV_RELEASE;
+try_again:
spin_lock(&cookie->lock);
/* break links with all the active objects */
while (!hlist_empty(&cookie->backing_objects)) {
+ int n_reads;
object = hlist_entry(cookie->backing_objects.first,
struct fscache_object,
cookie_link);
_debug("RELEASE OBJ%x", object->debug_id);
- if (atomic_read(&object->n_reads)) {
+ set_bit(FSCACHE_COOKIE_WAITING_ON_READS, &cookie->flags);
+ n_reads = atomic_read(&object->n_reads);
+ if (n_reads) {
+ int n_ops = object->n_ops;
+ int n_in_progress = object->n_in_progress;
spin_unlock(&cookie->lock);
printk(KERN_ERR "FS-Cache:"
- " Cookie '%s' still has %d outstanding reads\n",
- cookie->def->name, atomic_read(&object->n_reads));
- BUG();
+ " Cookie '%s' still has %d outstanding reads (%d,%d)\n",
+ cookie->def->name,
+ n_reads, n_ops, n_in_progress);
+ wait_on_bit(&cookie->flags, FSCACHE_COOKIE_WAITING_ON_READS,
+ fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+ printk("Wait finished\n");
+ goto try_again;
}
/* detach each cache object from the object cookie */
diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c
index 30afdfa..c857ab8 100644
--- a/fs/fscache/operation.c
+++ b/fs/fscache/operation.c
@@ -340,8 +340,14 @@ void fscache_put_operation(struct fscache_operation *op)
object = op->object;
- if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags))
- atomic_dec(&object->n_reads);
+ if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags)) {
+ if (atomic_dec_and_test(&object->n_reads)) {
+ clear_bit(FSCACHE_COOKIE_WAITING_ON_READS,
+ &object->cookie->flags);
+ wake_up_bit(&object->cookie->flags,
+ FSCACHE_COOKIE_WAITING_ON_READS);
+ }
+ }
/* now... we may get called with the object spinlock held, so we
* complete the cleanup here only if we can immediately acquire the
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index 9879183..e3d6d93 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -301,6 +301,7 @@ struct fscache_cookie {
#define FSCACHE_COOKIE_PENDING_FILL 3 /* T if pending initial fill on object */
#define FSCACHE_COOKIE_FILLING 4 /* T if filling object incrementally */
#define FSCACHE_COOKIE_UNAVAILABLE 5 /* T if cookie is unavailable (error, etc) */
+#define FSCACHE_COOKIE_WAITING_ON_READS 6 /* T if cookie is waiting on reads */
};
extern struct fscache_cookie fscache_fsdef_index;
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