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[PATCH 6/6] block: improve permission conflict error message
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[PATCH 6/6] block: improve permission conflict error message |
Date: |
Mon, 3 May 2021 14:34:02 +0300 |
Now permissions are updated as follows:
1. do graph modifications ignoring permissions
2. do permission update
(of course, we rollback [1] if [2] fails)
So, on stage [2] we can't say which users are "old" and which are
"new" and exist only since [1]. And current error message is a bit
outdated. Let's improve it, to make everything clean.
While being here, add also a comment and some good assertions.
iotests 283, 307, qsd-jobs outputs are updated.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
block.c | 29 ++++++++++++++++++++-------
tests/qemu-iotests/283.out | 2 +-
tests/qemu-iotests/307.out | 2 +-
tests/qemu-iotests/tests/qsd-jobs.out | 2 +-
4 files changed, 25 insertions(+), 10 deletions(-)
diff --git a/block.c b/block.c
index 20efd7a7b0..3fc87fbf90 100644
--- a/block.c
+++ b/block.c
@@ -2040,20 +2040,35 @@ static char *bdrv_child_user_desc(BdrvChild *c)
return c->klass->get_parent_desc(c);
}
+/*
+ * Check that @a allows everything that @b needs. @a and @b must reference same
+ * child node.
+ */
static bool bdrv_a_allow_b(BdrvChild *a, BdrvChild *b, Error **errp)
{
- g_autofree char *user = NULL;
- g_autofree char *perm_names = NULL;
+ g_autofree char *a_user = NULL;
+ g_autofree char *a_against = NULL;
+ g_autofree char *b_user = NULL;
+ g_autofree char *b_perm = NULL;
+
+ assert(a->bs);
+ assert(a->bs == b->bs);
if ((b->perm & a->shared_perm) == b->perm) {
return true;
}
- perm_names = bdrv_perm_names(b->perm & ~a->shared_perm);
- user = bdrv_child_user_desc(a);
- error_setg(errp, "Conflicts with use by %s as '%s', which does not "
- "allow '%s' on %s",
- user, a->name, perm_names, bdrv_get_node_name(b->bs));
+ a_user = bdrv_child_user_desc(a);
+ a_against = bdrv_perm_names(b->perm & ~a->shared_perm);
+
+ b_user = bdrv_child_user_desc(b);
+ b_perm = bdrv_perm_names(b->perm);
+
+ error_setg(errp, "Permission conflict on node '%s': %s wants to use it as "
+ "'%s', which requires these permissions: %s. On the other hand
%s "
+ "wants to use it as '%s', which doesn't share: %s",
+ bdrv_get_node_name(b->bs),
+ b_user, b->name, b_perm, a_user, a->name, a_against);
return false;
}
diff --git a/tests/qemu-iotests/283.out b/tests/qemu-iotests/283.out
index c9397bfc44..92f3cc1ed5 100644
--- a/tests/qemu-iotests/283.out
+++ b/tests/qemu-iotests/283.out
@@ -5,7 +5,7 @@
{"execute": "blockdev-add", "arguments": {"driver": "blkdebug", "image":
"base", "node-name": "other", "take-child-perms": ["write"]}}
{"return": {}}
{"execute": "blockdev-backup", "arguments": {"device": "source", "sync":
"full", "target": "target"}}
-{"error": {"class": "GenericError", "desc": "Cannot append backup-top filter:
Conflicts with use by node 'source' as 'image', which does not allow 'write' on
base"}}
+{"error": {"class": "GenericError", "desc": "Cannot append backup-top filter:
Permission conflict on node 'base': node 'other' wants to use it as 'image',
which requires these permissions: write. On the other hand node 'source' wants
to use it as 'image', which doesn't share: write"}}
=== backup-top should be gone after job-finalize ===
diff --git a/tests/qemu-iotests/307.out b/tests/qemu-iotests/307.out
index 66bf2ddb74..e03932ba4f 100644
--- a/tests/qemu-iotests/307.out
+++ b/tests/qemu-iotests/307.out
@@ -53,7 +53,7 @@ exports available: 1
=== Add a writable export ===
{"execute": "block-export-add", "arguments": {"description": "This is the
writable second export", "id": "export1", "name": "export1", "node-name":
"fmt", "type": "nbd", "writable": true, "writethrough": true}}
-{"error": {"class": "GenericError", "desc": "Conflicts with use by block
device 'sda' as 'root', which does not allow 'write' on fmt"}}
+{"error": {"class": "GenericError", "desc": "Permission conflict on node
'fmt': unnamed block device wants to use it as 'root', which requires these
permissions: consistent read, write. On the other hand block device 'sda' wants
to use it as 'root', which doesn't share: write"}}
{"execute": "device_del", "arguments": {"id": "sda"}}
{"return": {}}
{"data": {"device": "sda", "path": "/machine/peripheral/sda"}, "event":
"DEVICE_DELETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
diff --git a/tests/qemu-iotests/tests/qsd-jobs.out
b/tests/qemu-iotests/tests/qsd-jobs.out
index 9f52255da8..b0596d2c95 100644
--- a/tests/qemu-iotests/tests/qsd-jobs.out
+++ b/tests/qemu-iotests/tests/qsd-jobs.out
@@ -16,7 +16,7 @@ QMP_VERSION
{"return": {}}
{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event":
"JOB_STATUS_CHANGE", "data": {"status": "created", "id": "job0"}}
{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event":
"JOB_STATUS_CHANGE", "data": {"status": "null", "id": "job0"}}
-{"error": {"class": "GenericError", "desc": "Conflicts with use by stream job
'job0' as 'intermediate node', which does not allow 'write' on fmt_base"}}
+{"error": {"class": "GenericError", "desc": "Permission conflict on node
'fmt_base': unnamed block device wants to use it as 'root', which requires
these permissions: consistent read, write. On the other hand stream job 'job0'
wants to use it as 'intermediate node', which doesn't share: write"}}
{"return": {}}
{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event":
"BLOCK_EXPORT_DELETED", "data": {"id": "export1"}}
*** done
--
2.29.2
- [PATCH 0/6] block permission updated follow-up, Vladimir Sementsov-Ogievskiy, 2021/05/03
- [PATCH 1/6] block: fix leak of tran in bdrv_root_attach_child, Vladimir Sementsov-Ogievskiy, 2021/05/03
- [PATCH 2/6] block: bdrv_reopen_multiple(): fix leak of tran object, Vladimir Sementsov-Ogievskiy, 2021/05/03
- [PATCH 6/6] block: improve permission conflict error message,
Vladimir Sementsov-Ogievskiy <=
- [PATCH 3/6] block-backend: improve blk_root_get_parent_desc(), Vladimir Sementsov-Ogievskiy, 2021/05/03
- [PATCH 4/6] block: improve bdrv_child_get_parent_desc(), Vladimir Sementsov-Ogievskiy, 2021/05/03
- [PATCH 5/6] block: simplify bdrv_child_user_desc(), Vladimir Sementsov-Ogievskiy, 2021/05/03
- [PATCH 7/6] block: document child argument of bdrv_attach_child_common(), Vladimir Sementsov-Ogievskiy, 2021/05/03