diff mbox series

[v3,03/26] migration: Always report an error in block_save_setup()

Message ID 20240304122844.1888308-4-clg@redhat.com (mailing list archive)
State New, archived
Headers show
Series migration: Improve error reporting | expand

Commit Message

Cédric Le Goater March 4, 2024, 12:28 p.m. UTC
This will prepare ground for futur changes adding an Error** argument
to the save_setup() handler. We need to make sure that on failure,
block_save_setup() always sets a new error.

Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 migration/block.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

Comments

Fabiano Rosas March 4, 2024, 9:04 p.m. UTC | #1
Cédric Le Goater <clg@redhat.com> writes:

> This will prepare ground for futur changes adding an Error** argument
> to the save_setup() handler. We need to make sure that on failure,
> block_save_setup() always sets a new error.
>
> Cc: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Cédric Le Goater <clg@redhat.com>
> ---
>  migration/block.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/migration/block.c b/migration/block.c
> index 8c6ebafacc1ffe930d1d4f19d968817b14852c69..06f5857cf049df3261d2cf1d7c3607ab92350ac6 100644
> --- a/migration/block.c
> +++ b/migration/block.c
> @@ -367,7 +367,7 @@ static void unset_dirty_tracking(void)
>      }
>  }
>  
> -static int init_blk_migration(QEMUFile *f)
> +static int init_blk_migration(QEMUFile *f, Error **errp)
>  {
>      BlockDriverState *bs;
>      BlkMigDevState *bmds;
> @@ -378,7 +378,6 @@ static int init_blk_migration(QEMUFile *f)
>          BlkMigDevState *bmds;
>          BlockDriverState *bs;
>      } *bmds_bs;
> -    Error *local_err = NULL;
>      int ret;
>  
>      GRAPH_RDLOCK_GUARD_MAINLOOP();

There's a negative return below at:

    for (i = 0, bs = bdrv_first(&it); bs; bs = bdrv_next(&it), i++) {
        if (bdrv_is_read_only(bs)) {
            continue;
        }

        sectors = bdrv_nb_sectors(bs);
        if (sectors <= 0) {
            ret = sectors;
                ^
            bdrv_next_cleanup(&it);
            goto out;
        }
        ...

I presume that must be covered by an error as well. A similar function
somewhere else reports:

        total_sectors = blk_nb_sectors(blk);
        if (total_sectors <= 0) {
            error_report("Error getting length of block device %s",
                         device_name);
            return -EINVAL;
        }

> @@ -439,9 +438,8 @@ static int init_blk_migration(QEMUFile *f)
>          bs = bmds_bs[i].bs;
>  
>          if (bmds) {
> -            ret = blk_insert_bs(bmds->blk, bs, &local_err);
> +            ret = blk_insert_bs(bmds->blk, bs, errp);
>              if (ret < 0) {
> -                error_report_err(local_err);
>                  goto out;
>              }
>  
> @@ -711,6 +709,7 @@ static void block_migration_cleanup(void *opaque)
>  static int block_save_setup(QEMUFile *f, void *opaque)
>  {
>      int ret;
> +    Error *local_err = NULL;
>  
>      trace_migration_block_save("setup", block_mig_state.submitted,
>                                 block_mig_state.transferred);
> @@ -718,18 +717,27 @@ static int block_save_setup(QEMUFile *f, void *opaque)
>      warn_report("block migration is deprecated;"
>                  " use blockdev-mirror with NBD instead");
>  
> -    ret = init_blk_migration(f);
> +    ret = init_blk_migration(f, &local_err);
>      if (ret < 0) {
> +        error_report_err(local_err);
>          return ret;
>      }
>  
>      /* start track dirty blocks */
>      ret = set_dirty_tracking();
>      if (ret) {
> +        error_setg_errno(&local_err, -ret,
> +                         "Failed to start block dirty tracking");
> +        error_report_err(local_err);
>          return ret;
>      }
>  
>      ret = flush_blks(f);
> +    if (ret) {
> +        error_setg_errno(&local_err, -ret, "Flushing block failed");
> +        error_report_err(local_err);
> +        return ret;
> +    }
>      blk_mig_reset_dirty_cursor();
>      qemu_put_be64(f, BLK_MIG_FLAG_EOS);
Cédric Le Goater March 5, 2024, 8:23 a.m. UTC | #2
On 3/4/24 22:04, Fabiano Rosas wrote:
> Cédric Le Goater <clg@redhat.com> writes:
> 
>> This will prepare ground for futur changes adding an Error** argument
>> to the save_setup() handler. We need to make sure that on failure,
>> block_save_setup() always sets a new error.
>>
>> Cc: Stefan Hajnoczi <stefanha@redhat.com>
>> Signed-off-by: Cédric Le Goater <clg@redhat.com>
>> ---
>>   migration/block.c | 18 +++++++++++++-----
>>   1 file changed, 13 insertions(+), 5 deletions(-)
>>
>> diff --git a/migration/block.c b/migration/block.c
>> index 8c6ebafacc1ffe930d1d4f19d968817b14852c69..06f5857cf049df3261d2cf1d7c3607ab92350ac6 100644
>> --- a/migration/block.c
>> +++ b/migration/block.c
>> @@ -367,7 +367,7 @@ static void unset_dirty_tracking(void)
>>       }
>>   }
>>   
>> -static int init_blk_migration(QEMUFile *f)
>> +static int init_blk_migration(QEMUFile *f, Error **errp)
>>   {
>>       BlockDriverState *bs;
>>       BlkMigDevState *bmds;
>> @@ -378,7 +378,6 @@ static int init_blk_migration(QEMUFile *f)
>>           BlkMigDevState *bmds;
>>           BlockDriverState *bs;
>>       } *bmds_bs;
>> -    Error *local_err = NULL;
>>       int ret;
>>   
>>       GRAPH_RDLOCK_GUARD_MAINLOOP();
> 
> There's a negative return below at:
> 
>      for (i = 0, bs = bdrv_first(&it); bs; bs = bdrv_next(&it), i++) {
>          if (bdrv_is_read_only(bs)) {
>              continue;
>          }
> 
>          sectors = bdrv_nb_sectors(bs);
>          if (sectors <= 0) {
>              ret = sectors;
>                  ^
>              bdrv_next_cleanup(&it);
>              goto out;
>          }
>          ...


Indeed.

I understand that the bdrv_nb_sectors() == 0 case only breaks the loop but
it is not considered as an error. Could the block folks confirm please ?

Thanks,

C.

> 
> I presume that must be covered by an error as well. A similar function
> somewhere else reports:
> 
>          total_sectors = blk_nb_sectors(blk);
>          if (total_sectors <= 0) {
>              error_report("Error getting length of block device %s",
>                           device_name);
>              return -EINVAL;
>          }
>
>> @@ -439,9 +438,8 @@ static int init_blk_migration(QEMUFile *f)
>>           bs = bmds_bs[i].bs;
>>   
>>           if (bmds) {
>> -            ret = blk_insert_bs(bmds->blk, bs, &local_err);
>> +            ret = blk_insert_bs(bmds->blk, bs, errp);
>>               if (ret < 0) {
>> -                error_report_err(local_err);
>>                   goto out;
>>               }
>>   
>> @@ -711,6 +709,7 @@ static void block_migration_cleanup(void *opaque)
>>   static int block_save_setup(QEMUFile *f, void *opaque)
>>   {
>>       int ret;
>> +    Error *local_err = NULL;
>>   
>>       trace_migration_block_save("setup", block_mig_state.submitted,
>>                                  block_mig_state.transferred);
>> @@ -718,18 +717,27 @@ static int block_save_setup(QEMUFile *f, void *opaque)
>>       warn_report("block migration is deprecated;"
>>                   " use blockdev-mirror with NBD instead");
>>   
>> -    ret = init_blk_migration(f);
>> +    ret = init_blk_migration(f, &local_err);
>>       if (ret < 0) {
>> +        error_report_err(local_err);
>>           return ret;
>>       }
>>   
>>       /* start track dirty blocks */
>>       ret = set_dirty_tracking();
>>       if (ret) {
>> +        error_setg_errno(&local_err, -ret,
>> +                         "Failed to start block dirty tracking");
>> +        error_report_err(local_err);
>>           return ret;
>>       }
>>   
>>       ret = flush_blks(f);
>> +    if (ret) {
>> +        error_setg_errno(&local_err, -ret, "Flushing block failed");
>> +        error_report_err(local_err);
>> +        return ret;
>> +    }
>>       blk_mig_reset_dirty_cursor();
>>       qemu_put_be64(f, BLK_MIG_FLAG_EOS);
>
diff mbox series

Patch

diff --git a/migration/block.c b/migration/block.c
index 8c6ebafacc1ffe930d1d4f19d968817b14852c69..06f5857cf049df3261d2cf1d7c3607ab92350ac6 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -367,7 +367,7 @@  static void unset_dirty_tracking(void)
     }
 }
 
-static int init_blk_migration(QEMUFile *f)
+static int init_blk_migration(QEMUFile *f, Error **errp)
 {
     BlockDriverState *bs;
     BlkMigDevState *bmds;
@@ -378,7 +378,6 @@  static int init_blk_migration(QEMUFile *f)
         BlkMigDevState *bmds;
         BlockDriverState *bs;
     } *bmds_bs;
-    Error *local_err = NULL;
     int ret;
 
     GRAPH_RDLOCK_GUARD_MAINLOOP();
@@ -439,9 +438,8 @@  static int init_blk_migration(QEMUFile *f)
         bs = bmds_bs[i].bs;
 
         if (bmds) {
-            ret = blk_insert_bs(bmds->blk, bs, &local_err);
+            ret = blk_insert_bs(bmds->blk, bs, errp);
             if (ret < 0) {
-                error_report_err(local_err);
                 goto out;
             }
 
@@ -711,6 +709,7 @@  static void block_migration_cleanup(void *opaque)
 static int block_save_setup(QEMUFile *f, void *opaque)
 {
     int ret;
+    Error *local_err = NULL;
 
     trace_migration_block_save("setup", block_mig_state.submitted,
                                block_mig_state.transferred);
@@ -718,18 +717,27 @@  static int block_save_setup(QEMUFile *f, void *opaque)
     warn_report("block migration is deprecated;"
                 " use blockdev-mirror with NBD instead");
 
-    ret = init_blk_migration(f);
+    ret = init_blk_migration(f, &local_err);
     if (ret < 0) {
+        error_report_err(local_err);
         return ret;
     }
 
     /* start track dirty blocks */
     ret = set_dirty_tracking();
     if (ret) {
+        error_setg_errno(&local_err, -ret,
+                         "Failed to start block dirty tracking");
+        error_report_err(local_err);
         return ret;
     }
 
     ret = flush_blks(f);
+    if (ret) {
+        error_setg_errno(&local_err, -ret, "Flushing block failed");
+        error_report_err(local_err);
+        return ret;
+    }
     blk_mig_reset_dirty_cursor();
     qemu_put_be64(f, BLK_MIG_FLAG_EOS);