[Qemu-devel] [PATCH v4 0/3] Add bdrv_get_device_or_node_name()

[Qemu-devel] [PATCH v4 0/3] Add bdrv_get_device_or_node_name()

[Alberto Garcia]

This series contains a couple of minor changes suggested by Markus in
the previous one. I removed the Reviewed-by line by Max in the
modified patch even if the changes are small, hope that's ok.

v4:
- Fix documentation of the 'node-name' field in BLOCK_IMAGE_CORRUPTED.
  Its annotation is now (json-string, optional).
- Clarify that the 'device' field can be empty even if it's always
  present for compatibility reasons.

v3:
- The node-name field in BLOCK_IMAGE_CORRUPTED is now Since: 2.4
- Remove the QERR_ macros instead of updating them. The text message
  is adapted to each case where applicable, and 'device' is renamed to
  'node' only where it makes sense.

v2:
- bdrv_get_device_or_node_name() includes a comment explaining its
  usage.
- The error messages have been updated to say 'node' instead of
  'device' where appropriate.
- The BLOCK_IMAGE_CORRUPTED event has a new 'node-name' field.

Regards,

Berto

Alberto Garcia (3):
  block: add bdrv_get_device_or_node_name()
  block: use bdrv_get_device_or_node_name() in error messages
  block: add 'node-name' field to BLOCK_IMAGE_CORRUPTED

 block.c                   | 33 +++++++++++++++++++++------------
 block/qcow.c              |  8 ++++----
 block/qcow2.c             | 10 +++++++---
 block/qed.c               |  2 +-
 block/quorum.c            |  5 +----
 block/snapshot.c          | 12 ++++++------
 block/vdi.c               |  6 +++---
 block/vhdx.c              |  6 +++---
 block/vmdk.c              |  8 ++++----
 block/vpc.c               |  6 +++---
 block/vvfat.c             |  7 ++++---
 blockdev.c                |  9 +++++----
 docs/qmp/qmp-events.txt   | 21 +++++++++++++--------
 include/block/block.h     |  1 +
 include/qapi/qmp/qerror.h |  6 ------
 qapi/block-core.json      | 17 +++++++++++------
 16 files changed, 87 insertions(+), 70 deletions(-)

-- 
2.1.4

[Qemu-devel] [PATCH 1/3] block: add bdrv_get_device_or_node_name()

[Alberto Garcia]

This function gets the device name associated with a BlockDriverState,
or its node name if the device name is empty.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block.c               | 9 +++++++++
 block/quorum.c        | 5 +----
 include/block/block.h | 1 +
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/block.c b/block.c
index f2f8ae7..24adfc1 100644
--- a/block.c
+++ b/block.c
@@ -3953,6 +3953,15 @@ const char *bdrv_get_device_name(const BlockDriverState *bs)
     return bs->blk ? blk_name(bs->blk) : "";
 }
 
+/* This can be used to identify nodes that might not have a device
+ * name associated. Since node and device names live in the same
+ * namespace, the result is unambiguous. The exception is if both are
+ * absent, then this returns an empty (non-null) string. */
+const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
+{
+    return bs->blk ? blk_name(bs->blk) : bs->node_name;
+}
+
 int bdrv_get_flags(BlockDriverState *bs)
 {
     return bs->open_flags;
diff --git a/block/quorum.c b/block/quorum.c
index 437b122..f91ef75 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -226,10 +226,7 @@ static void quorum_report_bad(QuorumAIOCB *acb, char *node_name, int ret)
 
 static void quorum_report_failure(QuorumAIOCB *acb)
 {
-    const char *reference = bdrv_get_device_name(acb->common.bs)[0] ?
-                            bdrv_get_device_name(acb->common.bs) :
-                            acb->common.bs->node_name;
-
+    const char *reference = bdrv_get_device_or_node_name(acb->common.bs);
     qapi_event_send_quorum_failure(reference, acb->sector_num,
                                    acb->nb_sectors, &error_abort);
 }
diff --git a/include/block/block.h b/include/block/block.h
index 4c57d63..b285e0d 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -398,6 +398,7 @@ void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
                          void *opaque);
 const char *bdrv_get_node_name(const BlockDriverState *bs);
 const char *bdrv_get_device_name(const BlockDriverState *bs);
+const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
 int bdrv_get_flags(BlockDriverState *bs);
 int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,
                           const uint8_t *buf, int nb_sectors);
-- 
2.1.4

Re: [Qemu-devel] [PATCH 1/3] block: add bdrv_get_device_or_node_name()

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 1447 bytes --]

On 04/08/2015 03:29 AM, Alberto Garcia wrote:
> This function gets the device name associated with a BlockDriverState,
> or its node name if the device name is empty.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> ---
>  block.c               | 9 +++++++++
>  block/quorum.c        | 5 +----
>  include/block/block.h | 1 +
>  3 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/block.c b/block.c
> index f2f8ae7..24adfc1 100644
> --- a/block.c
> +++ b/block.c
> @@ -3953,6 +3953,15 @@ const char *bdrv_get_device_name(const BlockDriverState *bs)
>      return bs->blk ? blk_name(bs->blk) : "";
>  }
>  
> +/* This can be used to identify nodes that might not have a device
> + * name associated. Since node and device names live in the same
> + * namespace, the result is unambiguous. The exception is if both are
> + * absent, then this returns an empty (non-null) string. */
> +const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
> +{
> +    return bs->blk ? blk_name(bs->blk) : bs->node_name;

I had to check; bs->node_name is an array rather than a pointer, so it
always contains a non-null string (whether or not it is the empty
string), so your comment is correct.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
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[Qemu-devel] [PATCH 2/3] block: use bdrv_get_device_or_node_name() in error messages

[Alberto Garcia]

There are several error messages that identify a BlockDriverState by
its device name. However those errors can be produced in nodes that
don't have a device name associated.

In those cases we should use bdrv_get_device_or_node_name() to fall
back to the node name and produce a more meaningful message. The
messages are also updated to use the more generic term 'node' instead
of 'device'.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block.c                   | 24 ++++++++++++------------
 block/qcow.c              |  8 ++++----
 block/qcow2.c             |  2 +-
 block/qed.c               |  2 +-
 block/snapshot.c          | 12 ++++++------
 block/vdi.c               |  6 +++---
 block/vhdx.c              |  6 +++---
 block/vmdk.c              |  8 ++++----
 block/vpc.c               |  6 +++---
 block/vvfat.c             |  7 ++++---
 blockdev.c                |  9 +++++----
 include/qapi/qmp/qerror.h |  6 ------
 12 files changed, 46 insertions(+), 50 deletions(-)

diff --git a/block.c b/block.c
index 24adfc1..25289ef 100644
--- a/block.c
+++ b/block.c
@@ -1224,8 +1224,8 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
         bdrv_op_unblock_all(bs->backing_hd, bs->backing_blocker);
     } else if (backing_hd) {
         error_setg(&bs->backing_blocker,
-                   "device is used as backing hd of '%s'",
-                   bdrv_get_device_name(bs));
+                   "node is used as backing hd of '%s'",
+                   bdrv_get_device_or_node_name(bs));
     }
 
     bs->backing_hd = backing_hd;
@@ -1812,8 +1812,8 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
      * to r/w */
     if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) &&
         reopen_state->flags & BDRV_O_RDWR) {
-        error_set(errp, QERR_DEVICE_IS_READ_ONLY,
-                  bdrv_get_device_name(reopen_state->bs));
+        error_setg(errp, "Node '%s' is read only",
+                   bdrv_get_device_or_node_name(reopen_state->bs));
         goto error;
     }
 
@@ -1839,9 +1839,9 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
     } else {
         /* It is currently mandatory to have a bdrv_reopen_prepare()
          * handler for each supported drv. */
-        error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-                  drv->format_name, bdrv_get_device_name(reopen_state->bs),
-                 "reopening of file");
+        error_setg(errp, "Block format '%s' used by node '%s' "
+                   "does not support reopening files", drv->format_name,
+                   bdrv_get_device_or_node_name(reopen_state->bs));
         ret = -1;
         goto error;
     }
@@ -3797,8 +3797,8 @@ void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp)
 {
     if (key) {
         if (!bdrv_is_encrypted(bs)) {
-            error_setg(errp, "Device '%s' is not encrypted",
-                      bdrv_get_device_name(bs));
+            error_setg(errp, "Node '%s' is not encrypted",
+                      bdrv_get_device_or_node_name(bs));
         } else if (bdrv_set_key(bs, key) < 0) {
             error_set(errp, QERR_INVALID_PASSWORD);
         }
@@ -3806,7 +3806,7 @@ void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp)
         if (bdrv_key_required(bs)) {
             error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED,
                       "'%s' (%s) is encrypted",
-                      bdrv_get_device_name(bs),
+                      bdrv_get_device_or_node_name(bs),
                       bdrv_get_encrypted_filename(bs));
         }
     }
@@ -5581,8 +5581,8 @@ bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
     if (!QLIST_EMPTY(&bs->op_blockers[op])) {
         blocker = QLIST_FIRST(&bs->op_blockers[op]);
         if (errp) {
-            error_setg(errp, "Device '%s' is busy: %s",
-                       bdrv_get_device_name(bs),
+            error_setg(errp, "Node '%s' is busy: %s",
+                       bdrv_get_device_or_node_name(bs),
                        error_get_pretty(blocker->reason));
         }
         return true;
diff --git a/block/qcow.c b/block/qcow.c
index 0558969..ab89328 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -124,7 +124,7 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
         snprintf(version, sizeof(version), "QCOW version %" PRIu32,
                  header.version);
         error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
-                  bdrv_get_device_name(bs), "qcow", version);
+                  bdrv_get_device_or_node_name(bs), "qcow", version);
         ret = -ENOTSUP;
         goto fail;
     }
@@ -229,9 +229,9 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* Disable migration when qcow images are used */
-    error_set(&s->migration_blocker,
-              QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-              "qcow", bdrv_get_device_name(bs), "live migration");
+    error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
+               "does not support live migration",
+               bdrv_get_device_or_node_name(bs));
     migrate_add_blocker(s->migration_blocker);
 
     qemu_co_mutex_init(&s->lock);
diff --git a/block/qcow2.c b/block/qcow2.c
index 32bdf75..168006b 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -207,7 +207,7 @@ static void GCC_FMT_ATTR(3, 4) report_unsupported(BlockDriverState *bs,
     va_end(ap);
 
     error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
-              bdrv_get_device_name(bs), "qcow2", msg);
+              bdrv_get_device_or_node_name(bs), "qcow2", msg);
 }
 
 static void report_unsupported_feature(BlockDriverState *bs,
diff --git a/block/qed.c b/block/qed.c
index 892b13c..7d32ce4 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -408,7 +408,7 @@ static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags,
         snprintf(buf, sizeof(buf), "%" PRIx64,
             s->header.features & ~QED_FEATURE_MASK);
         error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
-            bdrv_get_device_name(bs), "QED", buf);
+            bdrv_get_device_or_node_name(bs), "QED", buf);
         return -ENOTSUP;
     }
     if (!qed_is_cluster_size_valid(s->header.cluster_size)) {
diff --git a/block/snapshot.c b/block/snapshot.c
index 698e1a1..50ae610 100644
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -246,9 +246,9 @@ int bdrv_snapshot_delete(BlockDriverState *bs,
     if (bs->file) {
         return bdrv_snapshot_delete(bs->file, snapshot_id, name, errp);
     }
-    error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-              drv->format_name, bdrv_get_device_name(bs),
-              "internal snapshot deletion");
+    error_setg(errp, "Block format '%s' used by device '%s' "
+               "does not support internal snapshot deletion",
+               drv->format_name, bdrv_get_device_name(bs));
     return -ENOTSUP;
 }
 
@@ -329,9 +329,9 @@ int bdrv_snapshot_load_tmp(BlockDriverState *bs,
     if (drv->bdrv_snapshot_load_tmp) {
         return drv->bdrv_snapshot_load_tmp(bs, snapshot_id, name, errp);
     }
-    error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-              drv->format_name, bdrv_get_device_name(bs),
-              "temporarily load internal snapshot");
+    error_setg(errp, "Block format '%s' used by device '%s' "
+               "does not support temporarily loading internal snapshots",
+               drv->format_name, bdrv_get_device_name(bs));
     return -ENOTSUP;
 }
 
diff --git a/block/vdi.c b/block/vdi.c
index 53bd02f..7642ef3 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -502,9 +502,9 @@ static int vdi_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* Disable migration when vdi images are used */
-    error_set(&s->migration_blocker,
-              QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-              "vdi", bdrv_get_device_name(bs), "live migration");
+    error_setg(&s->migration_blocker, "The vdi format used by node '%s' "
+               "does not support live migration",
+               bdrv_get_device_or_node_name(bs));
     migrate_add_blocker(s->migration_blocker);
 
     qemu_co_mutex_init(&s->write_lock);
diff --git a/block/vhdx.c b/block/vhdx.c
index bb3ed45..01970c2 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -1002,9 +1002,9 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
     /* TODO: differencing files */
 
     /* Disable migration when VHDX images are used */
-    error_set(&s->migration_blocker,
-            QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-            "vhdx", bdrv_get_device_name(bs), "live migration");
+    error_setg(&s->migration_blocker, "The vhdx format used by node '%s' "
+               "does not support live migration",
+               bdrv_get_device_or_node_name(bs));
     migrate_add_blocker(s->migration_blocker);
 
     return 0;
diff --git a/block/vmdk.c b/block/vmdk.c
index 8410a15..fd94b8f 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -669,7 +669,7 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
         snprintf(buf, sizeof(buf), "VMDK version %" PRId32,
                  le32_to_cpu(header.version));
         error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
-                  bdrv_get_device_name(bs), "vmdk", buf);
+                  bdrv_get_device_or_node_name(bs), "vmdk", buf);
         return -ENOTSUP;
     } else if (le32_to_cpu(header.version) == 3 && (flags & BDRV_O_RDWR)) {
         /* VMware KB 2064959 explains that version 3 added support for
@@ -962,9 +962,9 @@ static int vmdk_open(BlockDriverState *bs, QDict *options, int flags,
     qemu_co_mutex_init(&s->lock);
 
     /* Disable migration when VMDK images are used */
-    error_set(&s->migration_blocker,
-              QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-              "vmdk", bdrv_get_device_name(bs), "live migration");
+    error_setg(&s->migration_blocker, "The vmdk format used by node '%s' "
+               "does not support live migration",
+               bdrv_get_device_or_node_name(bs));
     migrate_add_blocker(s->migration_blocker);
     g_free(buf);
     return 0;
diff --git a/block/vpc.c b/block/vpc.c
index 43e768e..37572ba 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -318,9 +318,9 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
     qemu_co_mutex_init(&s->lock);
 
     /* Disable migration when VHD images are used */
-    error_set(&s->migration_blocker,
-              QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-              "vpc", bdrv_get_device_name(bs), "live migration");
+    error_setg(&s->migration_blocker, "The vpc format used by node '%s' "
+               "does not support live migration",
+               bdrv_get_device_or_node_name(bs));
     migrate_add_blocker(s->migration_blocker);
 
     return 0;
diff --git a/block/vvfat.c b/block/vvfat.c
index 9be632f..e803589 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -1180,9 +1180,10 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
 
     /* Disable migration when vvfat is used rw */
     if (s->qcow) {
-        error_set(&s->migration_blocker,
-                  QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-                  "vvfat (rw)", bdrv_get_device_name(bs), "live migration");
+        error_setg(&s->migration_blocker,
+                   "The vvfat (rw) format used by node '%s' "
+                   "does not support live migration",
+                   bdrv_get_device_or_node_name(bs));
         migrate_add_blocker(s->migration_blocker);
     }
 
diff --git a/blockdev.c b/blockdev.c
index fbb3a79..30dc9d2 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1248,13 +1248,14 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
     }
 
     if (bdrv_is_read_only(bs)) {
-        error_set(errp, QERR_DEVICE_IS_READ_ONLY, device);
+        error_setg(errp, "Device '%s' is read only", device);
         return;
     }
 
     if (!bdrv_can_snapshot(bs)) {
-        error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-                  bs->drv->format_name, device, "internal snapshot");
+        error_setg(errp, "Block format '%s' used by device '%s' "
+                   "does not support internal snapshots",
+                   bs->drv->format_name, device);
         return;
     }
 
@@ -2055,7 +2056,7 @@ void qmp_block_resize(bool has_device, const char *device,
         error_set(errp, QERR_UNSUPPORTED);
         break;
     case -EACCES:
-        error_set(errp, QERR_DEVICE_IS_READ_ONLY, device);
+        error_setg(errp, "Device '%s' is read only", device);
         break;
     case -EBUSY:
         error_set(errp, QERR_DEVICE_IN_USE, device);
diff --git a/include/qapi/qmp/qerror.h b/include/qapi/qmp/qerror.h
index 57a62d4..e567339 100644
--- a/include/qapi/qmp/qerror.h
+++ b/include/qapi/qmp/qerror.h
@@ -37,9 +37,6 @@ void qerror_report_err(Error *err);
 #define QERR_BASE_NOT_FOUND \
     ERROR_CLASS_GENERIC_ERROR, "Base '%s' not found"
 
-#define QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED \
-    ERROR_CLASS_GENERIC_ERROR, "Block format '%s' used by device '%s' does not support feature '%s'"
-
 #define QERR_BLOCK_JOB_NOT_READY \
     ERROR_CLASS_GENERIC_ERROR, "The active block job for device '%s' cannot be completed"
 
@@ -58,9 +55,6 @@ void qerror_report_err(Error *err);
 #define QERR_DEVICE_IN_USE \
     ERROR_CLASS_GENERIC_ERROR, "Device '%s' is in use"
 
-#define QERR_DEVICE_IS_READ_ONLY \
-    ERROR_CLASS_GENERIC_ERROR, "Device '%s' is read only"
-
 #define QERR_DEVICE_NO_HOTPLUG \
     ERROR_CLASS_GENERIC_ERROR, "Device '%s' does not support hotplugging"
 
-- 
2.1.4

Re: [Qemu-devel] [PATCH 2/3] block: use bdrv_get_device_or_node_name() in error messages

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 2980 bytes --]

On 04/08/2015 03:29 AM, Alberto Garcia wrote:
> There are several error messages that identify a BlockDriverState by
> its device name. However those errors can be produced in nodes that
> don't have a device name associated.
> 
> In those cases we should use bdrv_get_device_or_node_name() to fall
> back to the node name and produce a more meaningful message. The
> messages are also updated to use the more generic term 'node' instead
> of 'device'.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> ---

> +++ b/block/snapshot.c
> @@ -246,9 +246,9 @@ int bdrv_snapshot_delete(BlockDriverState *bs,
>      if (bs->file) {
>          return bdrv_snapshot_delete(bs->file, snapshot_id, name, errp);
>      }
> -    error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
> -              drv->format_name, bdrv_get_device_name(bs),
> -              "internal snapshot deletion");
> +    error_setg(errp, "Block format '%s' used by device '%s' "
> +               "does not support internal snapshot deletion",
> +               drv->format_name, bdrv_get_device_name(bs));
>      return -ENOTSUP;
>  }
>  
> @@ -329,9 +329,9 @@ int bdrv_snapshot_load_tmp(BlockDriverState *bs,
>      if (drv->bdrv_snapshot_load_tmp) {
>          return drv->bdrv_snapshot_load_tmp(bs, snapshot_id, name, errp);
>      }
> -    error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
> -              drv->format_name, bdrv_get_device_name(bs),
> -              "temporarily load internal snapshot");
> +    error_setg(errp, "Block format '%s' used by device '%s' "
> +               "does not support temporarily loading internal snapshots",
> +               drv->format_name, bdrv_get_device_name(bs));

Should these two messages use 'node' instead of 'device'?  After all, a
format is tied to a node (as a backing chain can involve multiple nodes
using different formats)


> +++ b/blockdev.c
> @@ -1248,13 +1248,14 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
>      }
>  
>      if (bdrv_is_read_only(bs)) {
> -        error_set(errp, QERR_DEVICE_IS_READ_ONLY, device);
> +        error_setg(errp, "Device '%s' is read only", device);
>          return;
>      }

This one is probably fine as device;

>  
>      if (!bdrv_can_snapshot(bs)) {
> -        error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
> -                  bs->drv->format_name, device, "internal snapshot");
> +        error_setg(errp, "Block format '%s' used by device '%s' "
> +                   "does not support internal snapshots",
> +                   bs->drv->format_name, device);

but this is probably another one where node may be better.

But it's already a strict improvement, so I can live with:

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH 2/3] block: use bdrv_get_device_or_node_name() in error messages

[Alberto Garcia]

On Wed, Apr 08, 2015 at 10:27:34AM -0600, Eric Blake wrote:

> > +++ b/block/snapshot.c
> > @@ -246,9 +246,9 @@ int bdrv_snapshot_delete(BlockDriverState *bs,
> >      if (bs->file) {
> >          return bdrv_snapshot_delete(bs->file, snapshot_id, name, errp);
> >      }
> > -    error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
> > -              drv->format_name, bdrv_get_device_name(bs),
> > -              "internal snapshot deletion");
> > +    error_setg(errp, "Block format '%s' used by device '%s' "
> > +               "does not support internal snapshot deletion",
> > +               drv->format_name, bdrv_get_device_name(bs));
> >      return -ENOTSUP;
> >  }
> >  
> > @@ -329,9 +329,9 @@ int bdrv_snapshot_load_tmp(BlockDriverState *bs,
> >      if (drv->bdrv_snapshot_load_tmp) {
> >          return drv->bdrv_snapshot_load_tmp(bs, snapshot_id, name, errp);
> >      }
> > -    error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
> > -              drv->format_name, bdrv_get_device_name(bs),
> > -              "temporarily load internal snapshot");
> > +    error_setg(errp, "Block format '%s' used by device '%s' "
> > +               "does not support temporarily loading internal snapshots",
> > +               drv->format_name, bdrv_get_device_name(bs));
> 
> Should these two messages use 'node' instead of 'device'?  After
> all, a format is tied to a node (as a backing chain can involve
> multiple nodes using different formats)
> 
> > +++ b/blockdev.c
> >      if (!bdrv_can_snapshot(bs)) {
> > -        error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
> > -                  bs->drv->format_name, device, "internal snapshot");
> > +        error_setg(errp, "Block format '%s' used by device '%s' "
> > +                   "does not support internal snapshots",
> > +                   bs->drv->format_name, device);
> 
> but this is probably another one where node may be better.

I decided to leave 'device' in all cases where 'bs' cannot possibly be
anything else that a root node.

In this latter case, for example, that bs is obtained using
blk_bs(blk_by_name(device)).

Berto

[Qemu-devel] [PATCH 3/3] block: add 'node-name' field to BLOCK_IMAGE_CORRUPTED

[Alberto Garcia]

Since this event can occur in nodes that cannot have a device name
associated, include also a field with the node name.

Signed-off-by: Alberto Garcia <berto@igalia.com>
---
 block/qcow2.c           |  8 ++++++--
 docs/qmp/qmp-events.txt | 21 +++++++++++++--------
 qapi/block-core.json    | 17 +++++++++++------
 3 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index 168006b..e7c78f1 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2809,6 +2809,7 @@ void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
                              int64_t size, const char *message_format, ...)
 {
     BDRVQcowState *s = bs->opaque;
+    const char *node_name;
     char *message;
     va_list ap;
 
@@ -2832,8 +2833,11 @@ void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
                 "corruption events will be suppressed\n", message);
     }
 
-    qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), message,
-                                          offset >= 0, offset, size >= 0, size,
+    node_name = bdrv_get_node_name(bs);
+    qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs),
+                                          *node_name != '\0', node_name,
+                                          message, offset >= 0, offset,
+                                          size >= 0, size,
                                           fatal, &error_abort);
     g_free(message);
 
diff --git a/docs/qmp/qmp-events.txt b/docs/qmp/qmp-events.txt
index d759d19..b19e490 100644
--- a/docs/qmp/qmp-events.txt
+++ b/docs/qmp/qmp-events.txt
@@ -31,21 +31,26 @@ Example:
 BLOCK_IMAGE_CORRUPTED
 ---------------------
 
-Emitted when a disk image is being marked corrupt.
+Emitted when a disk image is being marked corrupt. The image can be
+identified by its device or node name. The 'device' field is always
+present for compatibility reasons, but it can be empty ("") if the
+image does not have a device name associated.
 
 Data:
 
-- "device": Device name (json-string)
-- "msg":    Informative message (e.g., reason for the corruption) (json-string)
-- "offset": If the corruption resulted from an image access, this is the access
-            offset into the image (json-int)
-- "size":   If the corruption resulted from an image access, this is the access
-            size (json-int)
+- "device":    Device name (json-string)
+- "node-name": Node name (json-string, optional)
+- "msg":       Informative message (e.g., reason for the corruption)
+               (json-string)
+- "offset":    If the corruption resulted from an image access, this
+               is the access offset into the image (json-int)
+- "size":      If the corruption resulted from an image access, this
+               is the access size (json-int)
 
 Example:
 
 { "event": "BLOCK_IMAGE_CORRUPTED",
-    "data": { "device": "ide0-hd0",
+    "data": { "device": "ide0-hd0", "node-name": "node0",
         "msg": "Prevented active L1 table overwrite", "offset": 196608,
         "size": 65536 },
     "timestamp": { "seconds": 1378126126, "microseconds": 966463 } }
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 7873084..21e6cb5 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1754,7 +1754,11 @@
 #
 # Emitted when a corruption has been detected in a disk image
 #
-# @device: device name
+# @device: device name. This is always present for compatibility
+#          reasons, but it can be empty ("") if the image does not
+#          have a device name associated.
+#
+# @node-name: #optional node name (Since: 2.4)
 #
 # @msg: informative message for human consumption, such as the kind of
 #       corruption being detected. It should not be parsed by machine as it is
@@ -1773,11 +1777,12 @@
 # Since: 1.7
 ##
 { 'event': 'BLOCK_IMAGE_CORRUPTED',
-  'data': { 'device' : 'str',
-            'msg'    : 'str',
-            '*offset': 'int',
-            '*size'  : 'int',
-            'fatal'  : 'bool' } }
+  'data': { 'device'     : 'str',
+            '*node-name' : 'str',
+            'msg'        : 'str',
+            '*offset'    : 'int',
+            '*size'      : 'int',
+            'fatal'      : 'bool' } }
 
 ##
 # @BLOCK_IO_ERROR
-- 
2.1.4

Re: [Qemu-devel] [PATCH 3/3] block: add 'node-name' field to BLOCK_IMAGE_CORRUPTED

[Eric Blake]

On 04/08/2015 03:29 AM, Alberto Garcia wrote:
> Since this event can occur in nodes that cannot have a device name
> associated, include also a field with the node name.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  block/qcow2.c           |  8 ++++++--
>  docs/qmp/qmp-events.txt | 21 +++++++++++++--------
>  qapi/block-core.json    | 17 +++++++++++------
>  3 files changed, 30 insertions(+), 16 deletions(-)
> 
>  
> -- "device": Device name (json-string)
> -- "msg":    Informative message (e.g., reason for the corruption) (json-string)
> -- "offset": If the corruption resulted from an image access, this is the access
> -            offset into the image (json-int)
> -- "size":   If the corruption resulted from an image access, this is the access
> -            size (json-int)
> +- "device":    Device name (json-string)
> +- "node-name": Node name (json-string, optional)
> +- "msg":       Informative message (e.g., reason for the corruption)
> +               (json-string)
> +- "offset":    If the corruption resulted from an image access, this
> +               is the access offset into the image (json-int)
> +- "size":      If the corruption resulted from an image access, this
> +               is the access size (json-int)

Not your fault (so don't worry about fixing it here), but I still find
this definition of 'offset' confusing - is it the guest's offset, or the
host's offset?  I'm going to assume the host's offset (remember, on
qcow2, the guest offset 0 is never at host offset 0, because that is
reserved for the qcow2 header - but we CAN encounter a read error while
reading the qcow2 header).

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

Re: [Qemu-devel] [PATCH 3/3] block: add 'node-name' field to BLOCK_IMAGE_CORRUPTED

[Alberto Garcia]

On Wed, Apr 08, 2015 at 05:32:47PM -0600, Eric Blake wrote:

> > +- "device":    Device name (json-string)
> > +- "node-name": Node name (json-string, optional)
> > +- "msg":       Informative message (e.g., reason for the corruption)
> > +               (json-string)
> > +- "offset":    If the corruption resulted from an image access, this
> > +               is the access offset into the image (json-int)
> > +- "size":      If the corruption resulted from an image access, this
> > +               is the access size (json-int)
> 
> Not your fault (so don't worry about fixing it here), but I still
> find this definition of 'offset' confusing - is it the guest's
> offset, or the host's offset?

From the code it looks like it's the host's offset. And now that it
look into it both 'offset' and 'size' should be marked as optional
there (they are in block-core.json). I'll send a separate patch
correcting all those.

Berto

Re: [Qemu-devel] [PATCH 3/3] block: add 'node-name' field to BLOCK_IMAGE_CORRUPTED

[Max Reitz]

On 08.04.2015 11:29, Alberto Garcia wrote:
> Since this event can occur in nodes that cannot have a device name
> associated, include also a field with the node name.
>
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>   block/qcow2.c           |  8 ++++++--
>   docs/qmp/qmp-events.txt | 21 +++++++++++++--------
>   qapi/block-core.json    | 17 +++++++++++------
>   3 files changed, 30 insertions(+), 16 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>

Re: [Qemu-devel] [Qemu-block] [PATCH v4 0/3] Add bdrv_get_device_or_node_name()

[Stefan Hajnoczi]

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On Wed, Apr 08, 2015 at 12:29:17PM +0300, Alberto Garcia wrote:
> This series contains a couple of minor changes suggested by Markus in
> the previous one. I removed the Reviewed-by line by Max in the
> modified patch even if the changes are small, hope that's ok.
> 
> v4:
> - Fix documentation of the 'node-name' field in BLOCK_IMAGE_CORRUPTED.
>   Its annotation is now (json-string, optional).
> - Clarify that the 'device' field can be empty even if it's always
>   present for compatibility reasons.
> 
> v3:
> - The node-name field in BLOCK_IMAGE_CORRUPTED is now Since: 2.4
> - Remove the QERR_ macros instead of updating them. The text message
>   is adapted to each case where applicable, and 'device' is renamed to
>   'node' only where it makes sense.
> 
> v2:
> - bdrv_get_device_or_node_name() includes a comment explaining its
>   usage.
> - The error messages have been updated to say 'node' instead of
>   'device' where appropriate.
> - The BLOCK_IMAGE_CORRUPTED event has a new 'node-name' field.
> 
> Regards,
> 
> Berto
> 
> Alberto Garcia (3):
>   block: add bdrv_get_device_or_node_name()
>   block: use bdrv_get_device_or_node_name() in error messages
>   block: add 'node-name' field to BLOCK_IMAGE_CORRUPTED
> 
>  block.c                   | 33 +++++++++++++++++++++------------
>  block/qcow.c              |  8 ++++----
>  block/qcow2.c             | 10 +++++++---
>  block/qed.c               |  2 +-
>  block/quorum.c            |  5 +----
>  block/snapshot.c          | 12 ++++++------
>  block/vdi.c               |  6 +++---
>  block/vhdx.c              |  6 +++---
>  block/vmdk.c              |  8 ++++----
>  block/vpc.c               |  6 +++---
>  block/vvfat.c             |  7 ++++---
>  blockdev.c                |  9 +++++----
>  docs/qmp/qmp-events.txt   | 21 +++++++++++++--------
>  include/block/block.h     |  1 +
>  include/qapi/qmp/qerror.h |  6 ------
>  qapi/block-core.json      | 17 +++++++++++------
>  16 files changed, 87 insertions(+), 70 deletions(-)

Thanks, applied to my block-next tree:
https://github.com/stefanha/qemu/commits/block-next

Stefan

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