Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265651AbTFXDzi (ORCPT ); Mon, 23 Jun 2003 23:55:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265653AbTFXDzi (ORCPT ); Mon, 23 Jun 2003 23:55:38 -0400 Received: from dm1-36.slc.aros.net ([66.219.220.36]:45203 "EHLO cyprus") by vger.kernel.org with ESMTP id S265651AbTFXDz2 (ORCPT ); Mon, 23 Jun 2003 23:55:28 -0400 Message-ID: <3EF7CEF7.7020800@aros.net> Date: Mon, 23 Jun 2003 22:09:27 -0600 From: Lou Langholtz User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20030225 X-Accept-Language: en-us, en MIME-Version: 1.0 To: viro@parcelfarce.linux.theplanet.co.uk Cc: linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [PATCH] nbd driver for 2.5+: enhanced diagnostics support References: <3EF7B1C1.5040502@aros.net> <20030624025959.GO6754@parcelfarce.linux.theplanet.co.uk> In-Reply-To: <20030624025959.GO6754@parcelfarce.linux.theplanet.co.uk> Content-Type: multipart/mixed; boundary="------------000200070707000503070506" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 13464 Lines: 458 This is a multi-part message in MIME format. --------------000200070707000503070506 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit viro@parcelfarce.linux.theplanet.co.uk wrote: > . . . > >>+ case BLKROSET: return "set-read-only"; >>+ case BLKROGET: return "get-read-only"; >>+ case BLKGETSIZE: return "block-get-size"; >>+ case BLKFLSBUF: return "flush-buffer-cache"; >> >> > >The last 4 never make it to the driver (nor should they, being generic >ioctls). > > Aarg! A little too fast I was with me cut-and-patse! Actually though, BLKFLSBUF and BLKROSET do make it to the driver (at least according to my reading of linux-2.5.73/drivers/block/ioctl.c). The others are gone in the attached updated patch. >>+ reply.magic = ntohl(reply.magic); >>+ if (reply.magic != NBD_REPLY_MAGIC) { >>+ printk(KERN_ERR "%s: Wrong magic (0x%lx)\n", >>+ lo->disk->disk_name, >>+ (unsigned long)reply.magic); >> >> > > > >>+ reply.error = ntohl(reply.error); >>+ if (reply.error) { >>+ printk(KERN_ERR "%s: Other side returned error (%d)\n", >>+ lo->disk->disk_name, reply.error); >> >> > >Generally a bad taste - it's harmless in this case, but such endianness >conversions in place are asking for trouble. > Sure. I could have used local variables instead to hold the endianess results (which seems overkill). Or can just call ntohl again in printk and so it is now. >> lo->refcnt--; >>+ dprintk(DBG_RELEASE, "%s: %s refcnt=%d\n", lo->disk->disk_name, >>+ __FUNCTION__, lo->refcnt); >> /* N.B. Doesn't lo->file need an fput?? */ >> return 0; >> >> > >a) please, lose __FUNCTION__ - using it in macros is one thing, but >directly in a function that got a name shorter than `__FUNCTION__'? > > Done. >b) no, it doesn't. > > The N.B. is a left over from the original which agreeably can be cleaned up too. So it's gone now too. >c) ->refcnt is never used. How about losing it completely? Along with >->open() and ->release()... > > There's a few other things that could be "lost" too. Like lo->file and lo->blksize_bits. I'm trying to go one step at a time though with these patches. And actually ->open() and ->release() will be needed later when I get that far. ;-) >> sreq.flags = REQ_SPECIAL; >> nbd_cmd(&sreq) = NBD_CMD_DISC; >> >> > >;-/ > > That's how it was already. Maybe it's wrong too or just not so good. But changing this should wait till a patch that's not dealing with enhanced diags no?? >>+ sreq.sector = 0; >>+ sreq.nr_sectors = 0; >> >> > >Umm... What for? > I added some comments now to explain why. >> if (sizeof(struct nbd_request) != 28) { >>- printk(KERN_CRIT "Sizeof nbd_request needs to be 28 in order to work!\n" ); >>+ printk(KERN_CRIT "nbd: Sizeof nbd_request needs to be 28 in order to work!\n" ); >> return -EIO; >> } >> >> > >FWIW, I'm less than sure that struct nbd_request is worth defining. >We use it in two places - the check above and nbd_send_req() where >it is filled and then its address is cast to char *. It might be >better to use u32[7] directly and forget about all alignment issues. >Hell knows... In this situation I would probably just define an >enum for offsets and be done with that. Same goes for nbd_reply. > > I've thought about this too. I have to say so far that I don't like the idea though of getting rid of these structs. They're shared with the remote end also. Here's the revised patch then for enhanced diagnostics... --------------000200070707000503070506 Content-Type: text/plain; name="nbd-patch3.1" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="nbd-patch3.1" diff -urN linux-2.5.72-p2.5/drivers/block/nbd.c linux-2.5.73-p3.1/drivers/block/nbd.c --- linux-2.5.72-p2.5/drivers/block/nbd.c 2003-06-22 23:25:14.000000000 -0600 +++ linux-2.5.73-p3.1/drivers/block/nbd.c 2003-06-23 22:00:44.057332192 -0600 @@ -32,6 +32,7 @@ * memory corruption from module removal and possible memory corruption * from sending/receiving disk data. * 03-06-23 Cosmetic changes. + * 03-06-23 Enhance diagnostics support. * * possible FIXME: make set_sock / set_blksize / set_size / do_it one syscall * why not: would need verify_area and friends, would share yet another @@ -65,6 +66,23 @@ #define LO_MAGIC 0x68797548 +#ifdef NDEBUG +#define dprintk(flags, fmt...) +#else /* NDEBUG */ +#define dprintk(flags, fmt...) do { \ + if (debugflags & (flags)) printk(KERN_DEBUG fmt); \ +} while (0) +#define DBG_OPEN 0x0001 +#define DBG_RELEASE 0x0002 +#define DBG_IOCTL 0x0004 +#define DBG_INIT 0x0010 +#define DBG_EXIT 0x0020 +#define DBG_BLKDEV 0x0100 +#define DBG_RX 0x0200 +#define DBG_TX 0x0400 +static unsigned int debugflags; +#endif /* NDEBUG */ + static struct nbd_device nbd_dev[MAX_NBD]; /* @@ -79,19 +97,47 @@ */ static spinlock_t nbd_lock = SPIN_LOCK_UNLOCKED; -#define DEBUG( s ) -/* #define DEBUG( s ) printk( s ) - */ - static int requests_in; static int requests_out; +#ifndef NDEBUG +static const char *ioctl_cmd_to_ascii(int cmd) +{ + switch (cmd) { + case NBD_SET_SOCK: return "set-sock"; + case NBD_SET_BLKSIZE: return "set-blksize"; + case NBD_SET_SIZE: return "set-size"; + case NBD_DO_IT: return "do-it"; + case NBD_CLEAR_SOCK: return "clear-sock"; + case NBD_CLEAR_QUE: return "clear-que"; + case NBD_PRINT_DEBUG: return "print-debug"; + case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; + case NBD_DISCONNECT: return "disconnect"; + case BLKROSET: return "set-read-only"; + case BLKFLSBUF: return "flush-buffer-cache"; + } + return "unknown"; +} + +static const char *nbdcmd_to_ascii(int cmd) +{ + switch (cmd) { + case NBD_CMD_READ: return "read"; + case NBD_CMD_WRITE: return "write"; + case NBD_CMD_DISC: return "disconnect"; + } + return "invalid"; +} +#endif /* NDEBUG */ + static void nbd_end_request(struct request *req) { int uptodate = (req->errors == 0) ? 1 : 0; request_queue_t *q = req->q; unsigned long flags; + dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, + req, uptodate? "done": "failed"); #ifdef PARANOIA requests_out++; #endif @@ -193,8 +239,6 @@ unsigned long size = req->nr_sectors << 9; struct socket *sock = lo->sock; - DEBUG("nbd: sending control, "); - request.magic = htonl(NBD_REQUEST_MAGIC); request.type = htonl(nbd_cmd(req)); request.from = cpu_to_be64((u64) req->sector << 9); @@ -204,15 +248,19 @@ down(&lo->tx_lock); if (!sock || !lo->sock) { - printk(KERN_ERR "%s: Attempted sendmsg to closed socket\n", + printk(KERN_ERR "%s: Attempted send on closed socket\n", lo->disk->disk_name); goto error_out; } + dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n", + lo->disk->disk_name, req, + nbdcmd_to_ascii(nbd_cmd(req)), + req->sector << 9, req->nr_sectors << 9); result = sock_xmit(sock, 1, &request, sizeof(request), (nbd_cmd(req) == NBD_CMD_WRITE)? MSG_MORE: 0); if (result <= 0) { - printk(KERN_ERR "%s: Sendmsg failed for control (result %d)\n", + printk(KERN_ERR "%s: Send control failed (result %d)\n", lo->disk->disk_name, result); goto error_out; } @@ -229,7 +277,9 @@ flags = 0; if ((i < (bio->bi_vcnt - 1)) || bio->bi_next) flags = MSG_MORE; - DEBUG("data, "); + dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", + lo->disk->disk_name, req, + bvec->bv_len); result = sock_send_bvec(sock, bvec, flags); if (result <= 0) { printk(KERN_ERR "%s: Send data failed (result %d)\n", @@ -287,56 +337,57 @@ struct request *req; struct socket *sock = lo->sock; - DEBUG("reading control, "); reply.magic = 0; result = sock_xmit(sock, 0, &reply, sizeof(reply), MSG_WAITALL); if (result <= 0) { - printk(KERN_ERR "%s: Recv control failed (result %d)\n", + printk(KERN_ERR "%s: Receive control failed (result %d)\n", lo->disk->disk_name, result); lo->harderror = result; return NULL; } req = nbd_find_request(lo, reply.handle); if (req == NULL) { - printk(KERN_ERR "%s: Unexpected reply (result %d)\n", - lo->disk->disk_name, result); + printk(KERN_ERR "%s: Unexpected reply (%p)\n", + lo->disk->disk_name, reply.handle); lo->harderror = result; return NULL; } - DEBUG("ok, "); if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { - printk(KERN_ERR "%s: Not enough magic (result %d)\n", - lo->disk->disk_name, result); + printk(KERN_ERR "%s: Wrong magic (0x%lx)\n", + lo->disk->disk_name, + (unsigned long)ntohl(reply.magic)); lo->harderror = result; return NULL; } if (ntohl(reply.error)) { - printk(KERN_ERR "%s: Other side returned error (result %d)\n", - lo->disk->disk_name, result); + printk(KERN_ERR "%s: Other side returned error (%d)\n", + lo->disk->disk_name, ntohl(reply.error)); req->errors++; return req; } + dprintk(DBG_RX, "%s: request %p: got reply\n", + lo->disk->disk_name, req); if (nbd_cmd(req) == NBD_CMD_READ) { int i; struct bio *bio; - DEBUG("data, "); rq_for_each_bio(bio, req) { struct bio_vec *bvec; bio_for_each_segment(bvec, bio, i) { result = sock_recv_bvec(sock, bvec); if (result <= 0) { - printk(KERN_ERR "%s: Recv data failed (result %d)\n", + printk(KERN_ERR "%s: Receive data failed (result %d)\n", lo->disk->disk_name, result); lo->harderror = result; return NULL; } + dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", + lo->disk->disk_name, req, bvec->bv_len); } } } - DEBUG("done.\n"); return req; } @@ -347,7 +398,7 @@ BUG_ON(lo->magic != LO_MAGIC); while ((req = nbd_read_stat(lo)) != NULL) nbd_end_request(req); - printk(KERN_ALERT "%s: req should never be null\n", + printk(KERN_NOTICE "%s: req should never be null\n", lo->disk->disk_name); return; } @@ -388,6 +439,8 @@ struct nbd_device *lo; blkdev_dequeue_request(req); + dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%lx)\n", + req->rq_disk->disk_name, req, req->flags); if (!(req->flags & REQ_CMD)) goto error_out; @@ -431,7 +484,7 @@ nbd_send_req(lo, req); if (req->errors) { - printk(KERN_ERR "%s: nbd_send_req failed\n", + printk(KERN_ERR "%s: Request send failed\n", lo->disk->disk_name); spin_lock(&lo->queue_lock); list_del_init(&req->queuelist); @@ -456,6 +509,9 @@ static int nbd_open(struct inode *inode, struct file *file) { struct nbd_device *lo = inode->i_bdev->bd_disk->private_data; + + dprintk(DBG_OPEN, "%s: nbd_open refcnt=%d\n", lo->disk->disk_name, + lo->refcnt); lo->refcnt++; return 0; } @@ -463,11 +519,15 @@ static int nbd_release(struct inode *inode, struct file *file) { struct nbd_device *lo = inode->i_bdev->bd_disk->private_data; - if (lo->refcnt <= 0) - printk(KERN_ALERT "%s: %s: refcount(%d) <= 0\n", - lo->disk->disk_name, __FUNCTION__, lo->refcnt); + + if (lo->refcnt <= 0) { + printk(KERN_ALERT "%s: nbd_release: refcount(%d) <= 0\n", + lo->disk->disk_name, lo->refcnt); + BUG(); + } lo->refcnt--; - /* N.B. Doesn't lo->file need an fput?? */ + dprintk(DBG_RELEASE, "%s: nbd_release: refcnt=%d\n", + lo->disk->disk_name, lo->refcnt); return 0; } @@ -479,6 +539,8 @@ struct request sreq ; /* Anyone capable of this syscall can do *real bad* things */ + dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", + lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -487,6 +549,13 @@ printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); sreq.flags = REQ_SPECIAL; nbd_cmd(&sreq) = NBD_CMD_DISC; + /* + * Set these to sane values in case server implementation + * fails to check the request type first and also to keep + * debugging output cleaner. + */ + sreq.sector = 0; + sreq.nr_sectors = 0; if (!lo->sock) return -EINVAL; nbd_send_req(lo, &sreq); @@ -607,7 +676,7 @@ int i; if (sizeof(struct nbd_request) != 28) { - printk(KERN_CRIT "Sizeof nbd_request needs to be 28 in order to work!\n" ); + printk(KERN_CRIT "nbd: Sizeof nbd_request needs to be 28 in order to work!\n" ); return -EIO; } @@ -633,9 +702,10 @@ err = -EIO; goto out; } -#ifdef MODULE - printk("nbd: registered device at major %d\n", NBD_MAJOR); -#endif + + printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); + dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); + devfs_mk_dir("nbd"); for (i = 0; i < MAX_NBD; i++) { struct gendisk *disk = nbd_dev[i].disk; @@ -685,9 +755,7 @@ } devfs_remove("nbd"); unregister_blkdev(NBD_MAJOR, "nbd"); -#ifdef MODULE - printk("nbd: unregistered device at major %d\n", NBD_MAJOR); -#endif + printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); } module_init(nbd_init); @@ -696,4 +764,7 @@ MODULE_DESCRIPTION("Network Block Device"); MODULE_LICENSE("GPL"); - +#ifndef NDEBUG +MODULE_PARM(debugflags, "i"); +MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); +#endif --------------000200070707000503070506-- - 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/