Commit ef46ed88 authored by David Howells's avatar David Howells
Browse files

FS-Cache: Make cookie relinquishment wait for outstanding reads 



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: default avatarDavid Howells <dhowells@redhat.com>
parent 37491a13

fs/fscache/cookie.c

+14 −4
Original line number Diff line number Diff line
@@ -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 */

fs/fscache/operation.c

+8 −2
Original line number Diff line number Diff line
@@ -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

include/linux/fscache-cache.h

+1 −0
Original line number Diff line number Diff line
@@ -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;