diff mbox series

[03/16] block: Fix missing ERRP_GUARD() for error_prepend()

Message ID 20240228163723.1775791-4-zhao1.liu@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series Cleanup up to fix missing ERRP_GUARD() for error_prepend() | expand

Commit Message

Zhao Liu Feb. 28, 2024, 4:37 p.m. UTC 
From: Zhao Liu <zhao1.liu@intel.com>

As the comment in qapi/error, passing @errp to error_prepend() requires
ERRP_GUARD():

* = Why, when and how to use ERRP_GUARD() =
*
* Without ERRP_GUARD(), use of the @errp parameter is restricted:
...
* - It should not be passed to error_prepend(), error_vprepend() or
*   error_append_hint(), because that doesn't work with &error_fatal.
* ERRP_GUARD() lifts these restrictions.
*
* To use ERRP_GUARD(), add it right at the beginning of the function.
* @errp can then be used without worrying about the argument being
* NULL or &error_fatal.

ERRP_GUARD() could avoid the case when @errp is the pointer of
error_fatal, the user can't see this additional information, because
exit() happens in error_setg earlier than information is added [1].

In block.c, there're 4 functions passing @errp to error_prepend()
without ERRP_GUARD():
 - bdrv_co_create_opts_simple()
 - parse_json_filename()
 - bdrv_open_backing_file()
 - bdrv_append_temp_snapshot()

bdrv_co_create_opts_simple(), as an implementation of
BolckDriver.bdrv_co_create_opts(), its @errp parameter is so widely
sourced that it is necessary to protect it with ERRP_GUARD().

Though the @errp parameters passed to parse_json_filename(),
bdrv_open_backing_file() and bdrv_append_temp_snapshot() points to their
callers' local_err, to follow the requirement of @errp, also add missing
ERRP_GUARD() at their beginning.

[1]: Issue description in the commit message of commit ae7c80a7bd73
     ("error: New macro ERRP_GUARD()").

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
 block.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Eric Blake Feb. 29, 2024, 7:51 p.m. UTC | #1 
On Thu, Feb 29, 2024 at 12:37:10AM +0800, Zhao Liu wrote:
> From: Zhao Liu <zhao1.liu@intel.com>
> 
> As the comment in qapi/error, passing @errp to error_prepend() requires
> ERRP_GUARD():
> 

> 
> In block.c, there're 4 functions passing @errp to error_prepend()
> without ERRP_GUARD():
>  - bdrv_co_create_opts_simple()
>  - parse_json_filename()
>  - bdrv_open_backing_file()
>  - bdrv_append_temp_snapshot()
> 
> bdrv_co_create_opts_simple(), as an implementation of
> BolckDriver.bdrv_co_create_opts(), its @errp parameter is so widely

BlockDriver

> sourced that it is necessary to protect it with ERRP_GUARD().
> 
> Though the @errp parameters passed to parse_json_filename(),
> bdrv_open_backing_file() and bdrv_append_temp_snapshot() points to their
> callers' local_err, to follow the requirement of @errp, also add missing
> ERRP_GUARD() at their beginning.
> 
> [1]: Issue description in the commit message of commit ae7c80a7bd73
>      ("error: New macro ERRP_GUARD()").
> 
> Cc: Kevin Wolf <kwolf@redhat.com>
> Cc: Hanna Reitz <hreitz@redhat.com>
> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
> ---
>  block.c | 4 ++++
>  1 file changed, 4 insertions(+)

Reviewed-by: Eric Blake <eblake@redhat.com>
Zhao Liu March 8, 2024, 11:09 a.m. UTC | #2 
On Thu, Feb 29, 2024 at 01:51:16PM -0600, Eric Blake wrote:
> Date: Thu, 29 Feb 2024 13:51:16 -0600
> From: Eric Blake <eblake@redhat.com>
> Subject: Re: [PATCH 03/16] block: Fix missing ERRP_GUARD() for
>  error_prepend()
> 
> On Thu, Feb 29, 2024 at 12:37:10AM +0800, Zhao Liu wrote:
> > From: Zhao Liu <zhao1.liu@intel.com>
> > 
> > As the comment in qapi/error, passing @errp to error_prepend() requires
> > ERRP_GUARD():
> > 
> 
> > 
> > In block.c, there're 4 functions passing @errp to error_prepend()
> > without ERRP_GUARD():
> >  - bdrv_co_create_opts_simple()
> >  - parse_json_filename()
> >  - bdrv_open_backing_file()
> >  - bdrv_append_temp_snapshot()
> > 
> > bdrv_co_create_opts_simple(), as an implementation of
> > BolckDriver.bdrv_co_create_opts(), its @errp parameter is so widely
> 
> BlockDriver
>

Good catch! Thanks and will fix!

Regards,
Zhao
diff mbox series

Patch

diff --git a/block.c b/block.c
index 1ed9214f66ed..cf66c767a011 100644
--- a/block.c
+++ b/block.c
@@ -633,6 +633,7 @@  int coroutine_fn bdrv_co_create_opts_simple(BlockDriver *drv,
                                             QemuOpts *opts,
                                             Error **errp)
 {
+    ERRP_GUARD();
     BlockBackend *blk;
     QDict *options;
     int64_t size = 0;
@@ -1998,6 +1999,7 @@  fail_opts:
 
 static QDict *parse_json_filename(const char *filename, Error **errp)
 {
+    ERRP_GUARD();
     QObject *options_obj;
     QDict *options;
     int ret;
@@ -3585,6 +3587,7 @@  int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
                            const char *bdref_key, Error **errp)
 {
+    ERRP_GUARD();
     char *backing_filename = NULL;
     char *bdref_key_dot;
     const char *reference = NULL;
@@ -3851,6 +3854,7 @@  static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
                                                    QDict *snapshot_options,
                                                    Error **errp)
 {
+    ERRP_GUARD();
     g_autofree char *tmp_filename = NULL;
     int64_t total_size;
     QemuOpts *opts = NULL;