Commit b8f95e5d authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

fuse: umount should wait for all requests 



fuse_abort_conn() does not guarantee that all async requests have actually
finished aborting (i.e. their ->end() function is called).  This could
actually result in still used inodes after umount.

Add a helper to wait until all requests are fully done.  This is done by
looking at the "num_waiting" counter.  When this counter drops to zero, we
can be sure that no more requests are outstanding.

Fixes: 0d8e84b0 ("fuse: simplify request abort")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 45ff350b

fs/fuse/dev.c

+19 −4
Original line number Diff line number Diff line
@@ -127,6 +127,16 @@ static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background) 
	return !fc->initialized || (for_background && fc->blocked);

}



static void fuse_drop_waiting(struct fuse_conn *fc)

{

	if (fc->connected) {

		atomic_dec(&fc->num_waiting);

	} else if (atomic_dec_and_test(&fc->num_waiting)) {

		/* wake up aborters */

		wake_up_all(&fc->blocked_waitq);

	}

}



static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,

				       bool for_background)

{
@@ -175,7 +185,7 @@ static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages, 
	return req;



 out:

	atomic_dec(&fc->num_waiting);

	fuse_drop_waiting(fc);

	return ERR_PTR(err);

}
@@ -285,7 +295,7 @@ void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) 


		if (test_bit(FR_WAITING, &req->flags)) {

			__clear_bit(FR_WAITING, &req->flags);

			atomic_dec(&fc->num_waiting);

			fuse_drop_waiting(fc);

		}



		if (req->stolen_file)
@@ -371,7 +381,7 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req) 
	struct fuse_iqueue *fiq = &fc->iq;



	if (test_and_set_bit(FR_FINISHED, &req->flags))

		goto out_put_req;

		goto put_request;



	spin_lock(&fiq->waitq.lock);

	list_del_init(&req->intr_entry);
@@ -400,7 +410,7 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req) 
	wake_up(&req->waitq);

	if (req->end)

		req->end(fc, req);

out_put_req:

put_request:

	fuse_put_request(fc, req);

}
@@ -2143,6 +2153,11 @@ void fuse_abort_conn(struct fuse_conn *fc, bool is_abort) 
}

EXPORT_SYMBOL_GPL(fuse_abort_conn);



void fuse_wait_aborted(struct fuse_conn *fc)

{

	wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);

}



int fuse_dev_release(struct inode *inode, struct file *file)

{

	struct fuse_dev *fud = fuse_get_dev(file);

fs/fuse/fuse_i.h

+1 −0
Original line number Diff line number Diff line
@@ -862,6 +862,7 @@ void fuse_request_send_background_locked(struct fuse_conn *fc, 


/* Abort all requests */

void fuse_abort_conn(struct fuse_conn *fc, bool is_abort);

void fuse_wait_aborted(struct fuse_conn *fc);



/**

 * Invalidate inode attributes

fs/fuse/inode.c

+2 −0
Original line number Diff line number Diff line
@@ -394,6 +394,8 @@ static void fuse_put_super(struct super_block *sb) 
	fuse_send_destroy(fc);



	fuse_abort_conn(fc, false);

	fuse_wait_aborted(fc);



	mutex_lock(&fuse_mutex);

	list_del(&fc->entry);

	fuse_ctl_remove_conn(fc);

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