Re: /dev/loop0 over lvm... leading to d-state :-(

[Jens Axboe]

On Thu, Apr 05 2001, Jens Axboe wrote:
> To the LVM folks: you can't use b_dev or b_blocknr inside your
> make_request_fn, it destroys stacking drivers such as loop. And
> is just plain wrong in the general case too.

Irks, another one. lvm_make_request_fn also needs to call b_end_io
if a map fails. Updated patch attached, I'll collate further
patches if I find more :-)

-- 
Jens Axboe


--- /opt/kernel/linux-2.4.3/drivers/md/lvm.c    Mon Jan 29 01:11:20 2001
+++ drivers/md/lvm.c    Thu Apr  5 16:48:52 2001
@@ -148,6 +148,9 @@
  *                 procfs is always supported now. (JT)
  *    12/01/2001 - avoided flushing logical volume in case of shrinking
  *                 because of unecessary overhead in case of heavy updates
+ *    05/04/2001 - lvm_map bugs: don't use b_blocknr/b_dev in lvm_map, it
+ *                destroys stacking devices. call b_end_io on failed maps.
+ *                (Jens Axboe)
  *
  */
 
@@ -1480,14 +1483,14 @@
  */
 static int lvm_map(struct buffer_head *bh, int rw)
 {
-       int minor = MINOR(bh->b_dev);
+       int minor = MINOR(bh->b_rdev);
        int ret = 0;
        ulong index;
        ulong pe_start;
        ulong size = bh->b_size >> 9;
-       ulong rsector_tmp = bh->b_blocknr * size;
+       ulong rsector_tmp = bh->b_rsector;
        ulong rsector_sav;
-       kdev_t rdev_tmp = bh->b_dev;
+       kdev_t rdev_tmp = bh->b_rdev;
        kdev_t rdev_sav;
        vg_t *vg_this = vg[VG_BLK(minor)];
        lv_t *lv = vg_this->lv[LV_BLK(minor)];
@@ -1676,8 +1679,12 @@
  */
 static int lvm_make_request_fn(request_queue_t *q,
                               int rw,
-                              struct buffer_head *bh) {
-       return (lvm_map(bh, rw) < 0) ? 0 : 1;
+                              struct buffer_head *bh)
+{
+       int ret = lvm_map(bh, rw);
+       if (ret)
+               bh->b_end_io(bh, test_bit(BH_Uptodate, &bh->b_state));
+       return ret;
 }