From: Lou Langholtz <ldl@aros.net>
This third patch (for enhancing diagnostics support) applies incrementally
after my last LKML'd patch (for cosmetic changes). These changes introduce
configurable KERN_DEBUG level printk output for a variety of different
things that the driver does and provides the framework for enhanced future
debugging support as well.
drivers/block/nbd.c | 141 +++++++++++++++++++++++++++++++++++++++-------------
1 files changed, 106 insertions(+), 35 deletions(-)
diff -puN drivers/block/nbd.c~nbd-enhanced-diagnostics drivers/block/nbd.c
--- 25/drivers/block/nbd.c~nbd-enhanced-diagnostics 2003-06-26 18:39:30.000000000 -0700
+++ 25-akpm/drivers/block/nbd.c 2003-06-26 18:39:30.000000000 -0700
@@ -32,6 +32,7 @@
* memory corruption from module removal and possible memory corruption
* from sending/receiving disk data. <ldl@aros.net>
* 03-06-23 Cosmetic changes. <ldl@aros.net>
+ * 03-06-23 Enhance diagnostics support. <ldl@aros.net>
*
* 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 struct nbd_device nbd_dev[MAX_NBD
*/
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 @@ void nbd_send_req(struct nbd_device *lo,
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 @@ void nbd_send_req(struct nbd_device *lo,
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 @@ void nbd_send_req(struct nbd_device *lo,
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 *nbd_read_stat(struct nbd
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 @@ void nbd_do_it(struct nbd_device *lo)
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 @@ static void do_nbd_request(request_queue
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 @@ static void do_nbd_request(request_queue
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 void do_nbd_request(request_queue
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_open(struct inode *inode,
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 @@ static int nbd_ioctl(struct inode *inode
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 @@ static int nbd_ioctl(struct inode *inode
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 @@ static int __init nbd_init(void)
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 @@ static int __init nbd_init(void)
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 @@ static void __exit nbd_cleanup(void)
}
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_exit(nbd_cleanup);
MODULE_DESCRIPTION("Network Block Device");
MODULE_LICENSE("GPL");
-
+#ifndef NDEBUG
+MODULE_PARM(debugflags, "i");
+MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
+#endif
_