[Devel] [PATCH RHEL7 COMMIT] ploop: make error messages about intersecting extents more verbose (v2)

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-514.26.1.vz7.35.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-514.26.1.vz7.35.3
------>
commit a9706cc54cb7ce7ec6a6bb25d6a6355f5a9e19fd
Author: Maxim Patlasov <mpatlasov at virtuozzo.com>
Date:   Fri Aug 11 17:07:21 2017 +0400

    ploop: make error messages about intersecting extents more verbose (v2)
    
    There was a complain about intersecting extents:
    
    > [123825.298494] ploop_fb_add_free_extent(): intersected extentsploop_fb_add_free_extent(): intersected extents
    
    Next time it happens, we'll have more info to chase root cause.
    
    v2: added WARN_ONCE to taint kernel
    
    Signed-off-by: Maxim Patlasov <mpatlasov at virtuozzo.com>
---
 drivers/block/ploop/dev.c      | 32 +++++++++++++++++++++++++++++++-
 drivers/block/ploop/freeblks.c | 18 ++++++++++++++----
 2 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c
index eab6cb0..12fde00 100644
--- a/drivers/block/ploop/dev.c
+++ b/drivers/block/ploop/dev.c
@@ -2075,8 +2075,17 @@ static int ploop_entry_discard_req(struct ploop_request *preq)
 							preq->dst_cluster,
 							preq->dst_iblock, len);
 			preq->dst_iblock = 0;
-			if (err)
+			if (err) {
+				if (err == -EINVAL) {
+					printk("ploop_entry_discard_req1: "
+					       "(%lu %u; %u %u; %u %u)\n",
+					       preq->req_sector, preq->req_size,
+					       preq->req_cluster, preq->iblock,
+					       preq->dst_cluster, preq->dst_iblock);
+					WARN_ONCE(1, "add_free_extent failed\n");
+				}
 				goto err;
+			}
 		}
 
 		if (!preq->dst_iblock && preq->iblock) {
@@ -2089,6 +2098,14 @@ static int ploop_entry_discard_req(struct ploop_request *preq)
 		len = preq->req_cluster - preq->dst_cluster;
 		err = ploop_fb_add_free_extent(plo->fbd, preq->dst_cluster,
 						preq->dst_iblock, len);
+		if (err == -EINVAL) {
+			printk("ploop_entry_discard_req2: "
+			       "(%lu %u; %u %u; %u %u)\n",
+			       preq->req_sector, preq->req_size,
+			       preq->req_cluster, preq->iblock,
+			       preq->dst_cluster, preq->dst_iblock);
+			WARN_ONCE(1, "add_free_extent failed\n");
+		}
 	}
 
 err:
@@ -4469,6 +4486,19 @@ static int ploop_freeblks_ioc(struct ploop_device *plo, unsigned long arg)
 		rc = ploop_fb_add_free_extent(fbd, extent.clu,
 					extent.iblk, extent.len);
 		if (rc) {
+			if (rc == -EINVAL) {
+				printk("ploop_freeblks_ioc: n=%d\n", ctl.n_extents);
+				for (i = 0; i < ctl.n_extents; i++) {
+					if (copy_from_user(&extent, &extents[i],
+							   sizeof(extent))) {
+						printk("copy failed: i=%d\n", i);
+						break;
+					}
+					printk("ploop_freeblks_ioc: i=%d: %u %u %u\n",
+					       i, extent.clu, extent.iblk, extent.len);
+				}
+				WARN_ONCE(1, "add_free_extent failed\n");
+			}
 			ploop_fb_fini(fbd, rc);
 			goto exit;
 		}
diff --git a/drivers/block/ploop/freeblks.c b/drivers/block/ploop/freeblks.c
index a74a22d..ab907a3 100644
--- a/drivers/block/ploop/freeblks.c
+++ b/drivers/block/ploop/freeblks.c
@@ -867,14 +867,24 @@ int ploop_fb_add_free_extent(struct ploop_freeblks_desc *fbd,
 		tmp = list_entry(ex->list.next, struct ploop_freeblks_extent, list);
 
 		if (iblk + len > tmp->iblk) {
-			printk("ploop_fb_add_free_extent(): intersected extents");
+			int c = &ex->list != &fbd->fbd_free_list;
+			printk("ploop_fb_add_free_extent(): next (%u %u %u) "
+			       "intersects with (%u %u %u); ex (%u %u %d)\n",
+			       tmp->clu, tmp->iblk, tmp->len, clu, iblk, len,
+			       c ? ex->clu : 0, c ? ex->iblk : 0, c ? ex->len : -1);
 			return -EINVAL;
 		}
 	}
 
 	if (&ex->list != &fbd->fbd_free_list) {
 		if (ex->iblk + ex->len > iblk) {
-			printk("ploop_fb_add_free_extent(): intersected extents");
+			struct ploop_freeblks_extent *t = NULL;
+			if (ex->list.next != &fbd->fbd_free_list)
+				t = list_entry(ex->list.next, struct ploop_freeblks_extent, list);
+			printk("ploop_fb_add_free_extent(): ex (%u %u %u) "
+			       "intersects with (%u %u %u); next (%u %u %d)\n",
+			       ex->clu, ex->iblk, ex->len, clu, iblk, len,
+			       t ? t->clu : 0, t ? t->iblk : 0, t ? t->len : -1);
 			return -EINVAL;
 		}
 	}
@@ -912,7 +922,7 @@ int ploop_fb_add_reloc_extent(struct ploop_freeblks_desc *fbd,
 		rblk_extent = list_entry(fbd->fbd_reloc_list.prev,
 					 struct ploop_relocblks_extent, list);
 		if (rblk_extent->iblk + rblk_extent->len > iblk) {
-			printk("ploop_fb_add_reloc_extent(): extents should be sorted");
+			printk("ploop_fb_add_reloc_extent(): extents should be sorted\n");
 			return -EINVAL;
 		}
 
@@ -920,7 +930,7 @@ int ploop_fb_add_reloc_extent(struct ploop_freeblks_desc *fbd,
 			rblk_extent = list_entry(rblk_extent->list.next,
 					 struct ploop_relocblks_extent, list);
 			if (iblk + len > rblk_extent->iblk) {
-				printk("ploop_fb_add_reloc_extent(): intersected extents");
+				printk("ploop_fb_add_reloc_extent(): intersected extents\n");
 				return -EINVAL;
 			}
 		}