Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964826AbWCAC1E (ORCPT ); Tue, 28 Feb 2006 21:27:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964825AbWCAC1E (ORCPT ); Tue, 28 Feb 2006 21:27:04 -0500 Received: from saraswathi.solana.com ([198.99.130.12]:5356 "EHLO saraswathi.solana.com") by vger.kernel.org with ESMTP id S964819AbWCAC1B (ORCPT ); Tue, 28 Feb 2006 21:27:01 -0500 Date: Tue, 28 Feb 2006 21:28:00 -0500 From: Jeff Dike To: Miklos Szeredi Cc: fuse-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Add O_ASYNC support to FUSE Message-ID: <20060301022800.GA9624@ccure.user-mode-linux.org> References: <20060227183759.GA5669@ccure.user-mode-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4629 Lines: 144 Updated patch below... On Tue, Feb 28, 2006 at 11:15:16AM +0100, Miklos Szeredi wrote: > Yes, but you need to use fuse_get_conn() and check the result (see > fuse_dev_poll()). Fixed. > Although it may be possible that kill_fasync() races with the final > fput(), but as I see kill_fasync() only uses the file->f_owner field > which should still be valid before and during file->release(). > > Which BUG is triggered? I cleaned up a couple things, and I can't make it break any more. > This should be POLL_IN too, no? Duh, yes. > I like this style better: Fixed. Jeff # This adds asynchronous notification to FUSE - a FUSE server can # request O_ASYNC on a /dev/fuse file descriptor and receive SIGIO # when there is input available. # # One subtlety - fuse_dev_fasync, which is called when O_ASYNC is # requested, does no locking, unlink the other methods. I think it's # unnecessary, as the fuse_conn.fasync list is manipulated only by # fasync_helper and kill_fasync, which provide their own locking. It # would also be wrong to use the fuse_lock, as it's a spin lock and # fasync_helper can sleep. My one concern with this is the fuse_conn # going away underneath fuse_dev_fasync - sys_fcntl takes a reference # on the file struct, so this seems not to be a problem. # # Signed-off-by: Jeff Dike Index: host-2.6.15-fuse/fs/fuse/dev.c =================================================================== --- host-2.6.15-fuse.orig/fs/fuse/dev.c 2006-02-18 12:19:07.000000000 -0500 +++ host-2.6.15-fuse/fs/fuse/dev.c 2006-02-28 21:04:40.000000000 -0500 @@ -311,6 +311,7 @@ static void queue_request(struct fuse_co list_add_tail(&req->list, &fc->pending); req->state = FUSE_REQ_PENDING; wake_up(&fc->waitq); + kill_fasync(&fc->fasync, SIGIO, POLL_IN); } /* @@ -894,6 +895,7 @@ void fuse_abort_conn(struct fuse_conn *f end_requests(fc, &fc->pending); end_requests(fc, &fc->processing); wake_up_all(&fc->waitq); + kill_fasync(&fc->fasync, SIGIO, POLL_IN); } spin_unlock(&fuse_lock); } @@ -910,12 +912,26 @@ static int fuse_dev_release(struct inode end_requests(fc, &fc->processing); } spin_unlock(&fuse_lock); - if (fc) + if (fc) { kobject_put(&fc->kobj); + fasync_helper(-1, file, 0, &fc->fasync); + fc->fasync = NULL; + } return 0; } +static int fuse_dev_fasync(int fd, struct file *file, int on) +{ + struct fuse_conn *fc = fuse_get_conn(file); + + if (!fc) + return -ENODEV; + + /* No locking - fasync_helper does its own locking */ + return fasync_helper(fd, file, on, &fc->fasync); +} + struct file_operations fuse_dev_operations = { .owner = THIS_MODULE, .llseek = no_llseek, @@ -925,6 +941,7 @@ struct file_operations fuse_dev_operatio .writev = fuse_dev_writev, .poll = fuse_dev_poll, .release = fuse_dev_release, + .fasync = fuse_dev_fasync, }; static struct miscdevice fuse_miscdevice = { Index: host-2.6.15-fuse/fs/fuse/fuse_i.h =================================================================== --- host-2.6.15-fuse.orig/fs/fuse/fuse_i.h 2006-02-24 17:46:47.000000000 -0500 +++ host-2.6.15-fuse/fs/fuse/fuse_i.h 2006-02-24 18:24:49.000000000 -0500 @@ -318,6 +318,9 @@ struct fuse_conn { /** kobject */ struct kobject kobj; + + /** O_ASYNC requests */ + struct fasync_struct *fasync; }; static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) Index: host-2.6.15-fuse/fs/fuse/inode.c =================================================================== --- host-2.6.15-fuse.orig/fs/fuse/inode.c 2006-02-18 12:19:07.000000000 -0500 +++ host-2.6.15-fuse/fs/fuse/inode.c 2006-02-28 21:00:55.000000000 -0500 @@ -17,6 +17,7 @@ #include #include #include +#include MODULE_AUTHOR("Miklos Szeredi "); MODULE_DESCRIPTION("Filesystem in Userspace"); @@ -216,6 +217,7 @@ static void fuse_put_super(struct super_ spin_unlock(&fuse_lock); up_write(&fc->sbput_sem); /* Flush all readers on this fs */ + kill_fasync(&fc->fasync, SIGIO, POLL_IN); wake_up_all(&fc->waitq); kobject_del(&fc->kobj); kobject_put(&fc->kobj); @@ -409,6 +411,7 @@ static struct fuse_conn *new_conn(void) fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; fc->bdi.unplug_io_fn = default_unplug_io_fn; fc->reqctr = 0; + fc->fasync = NULL; } return fc; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/