| Message ID | 1490879707-6060-5-git-send-email-armbru@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 03/30/2017 08:15 AM, Markus Armbruster wrote: > However, A few places access the flat QDict directly: > > * Most of them access members that are always QString. Correct. > > * bdrv_open_inherit() accesses a boolean, carefully. Correct. > > * nfs_config() uses a QObject input visitor. Correct only because the > visited type contains nothing but QStrings. > > * nbd_config() and ssh_config() use a QObject input visitor, and the > visited types contain non-QStrings: InetSocketAddress members > @numeric, @to, @ipv4, @ipv6. -drive works as long as you don't try > to use them (they're all optional). @to is ignored anyway. > > Reproducer: > -drive driver=ssh,server.host=h,server.port=22,server.ipv4,path=p > -drive driver=nbd,server.type=inet,server.data.host=h,server.data.port=22,server.data.ipv4 > both fail with "Invalid parameter type for 'data.ipv4', expected: boolean" > > Add suitable comments to all these places. Mark the buggy ones FIXME. > > "Fortunately", -drive's driver-specific options are entirely > undocumented. > > Signed-off-by: Markus Armbruster <armbru@redhat.com> > --- > +++ b/block.c > @@ -1157,6 +1157,12 @@ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file, > if (file != NULL) { > filename = blk_bs(file)->filename; > } else { > + /* > + * Caution: direct use of non-string @options members is > + * problematic. When they come from -blockdev or blockdev_add, > + * members are typed according to the QAPI schema, but when > + * they come from -drive, they're all QString. > + */ > filename = qdict_get_try_str(options, "filename"); Did we get the latest round of comment tweaking in here? I was expecting to see something along the lines of: "Caution: accessing 'filename' from @options here is safe, but direct use of any non-string @options members would be problematic. When they come..." > } > > @@ -1324,6 +1330,12 @@ static int bdrv_fill_options(QDict **options, const char *filename, > BlockDriver *drv = NULL; > Error *local_err = NULL; > > + /* > + * Caution: direct use of non-string @options members is > + * problematic. When they come from -blockdev or blockdev_add, > + * members are typed according to the QAPI schema, but when they > + * come from -drive, they're all QString. > + */ > drvname = qdict_get_try_str(*options, "driver"); Again, wordsmithing might be nice to call out that 'driver' is safe, but future additions of other accesses must be careful. > @@ -1987,6 +2000,12 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, > qdict_extract_subqdict(parent_options, &options, bdref_key_dot); > g_free(bdref_key_dot); > > + /* > + * Caution: direct use of non-string @parent_options members is > + * problematic. When they come from -blockdev or blockdev_add, > + * members are typed according to the QAPI schema, but when they > + * come from -drive, they're all QString. > + */ > reference = qdict_get_try_str(parent_options, bdref_key); Again, wordsmithing to mention that bdref_key is safe. > if (reference || qdict_haskey(options, "file.filename")) { > backing_filename[0] = '\0'; > @@ -2059,6 +2078,12 @@ bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key, > qdict_extract_subqdict(options, &image_options, bdref_key_dot); > g_free(bdref_key_dot); > > + /* > + * Caution: direct use of non-string @options members is > + * problematic. When they come from -blockdev or blockdev_add, > + * members are typed according to the QAPI schema, but when they > + * come from -drive, they're all QString. > + */ > reference = qdict_get_try_str(options, bdref_key); Ditto. > if (!filename && !reference && !qdict_size(image_options)) { > if (!allow_none) { > @@ -2275,8 +2300,11 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, > } > > /* Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags. > - * FIXME: we're parsing the QDict to avoid having to create a > - * QemuOpts just for this, but neither option is optimal. */ > + * Caution: direct use of non-string @options members is > + * problematic. When they come from -blockdev or blockdev_add, > + * members are typed according to the QAPI schema, but when they > + * come from -drive, they're all QString. > + */ > if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") && > !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) { > flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR); Maybe here, the wordsmithing would mention that the extra hoops we jump through to cover both types is what makes access safe. > +++ b/block/nbd.c > @@ -278,6 +278,14 @@ static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options, Error **errp) > goto done; > } > > + /* > + * FIXME .numeric, .to, .ipv4 or .ipv6 don't work with -drive > + * server.type=inet. .to doesn't matter, it's ignored anyway. > + * That's because when @options come from -blockdev or > + * blockdev_add, members are typed according to the QAPI schema, > + * but when they come from -drive, they're all QString. The > + * visitor expects the former. > + */ This one is fine. > iv = qobject_input_visitor_new(crumpled_addr); > visit_type_SocketAddress(iv, NULL, &saddr, &local_err); > if (local_err) { > diff --git a/block/nfs.c b/block/nfs.c > index 3f43f6e..42407de 100644 > --- a/block/nfs.c > +++ b/block/nfs.c > @@ -474,6 +474,13 @@ static NFSServer *nfs_config(QDict *options, Error **errp) > goto out; > } > > + /* > + * Caution: this works only because all scalar members of > + * NFSServer are QString in @crumpled_addr. The visitor expects > + * @crumpled_addr to be typed according to the QAPI scherma. It > + * is when @options come from -blockdev or blockdev_add. But when > + * they come from -drive, they're all QString. > + */ > iv = qobject_input_visitor_new(crumpled_addr); This one is also fine. > visit_type_NFSServer(iv, NULL, &server, &local_error); > if (local_error) { > diff --git a/block/rbd.c b/block/rbd.c > index 498322b..b9a9526 100644 > --- a/block/rbd.c > +++ b/block/rbd.c > @@ -384,6 +384,12 @@ static int qemu_rbd_create(const char *filename, QemuOpts *opts, Error **errp) > goto exit; > } > > + /* > + * Caution: direct use of non-string @options members is > + * problematic. When they come from -blockdev or blockdev_add, > + * members are typed according to the QAPI schema, but when they > + * come from -drive, they're all QString. Here, wordsmithing may be worth mentioning that we are safe because these are all strings. > + */ > pool = qdict_get_try_str(options, "pool"); > conf = qdict_get_try_str(options, "conf"); > clientname = qdict_get_try_str(options, "user"); > diff --git a/block/ssh.c b/block/ssh.c > index 278e66f..471ba8a 100644 > --- a/block/ssh.c > +++ b/block/ssh.c > @@ -601,6 +601,14 @@ static InetSocketAddress *ssh_config(QDict *options, Error **errp) > goto out; > } > > + /* > + * FIXME .numeric, .to, .ipv4 or .ipv6 don't work with -drive. > + * .to doesn't matter, it's ignored anyway. > + * That's because when @options come from -blockdev or > + * blockdev_add, members are typed according to the QAPI schema, > + * but when they come from -drive, they're all QString. The > + * visitor expects the former. > + */ > iv = qobject_input_visitor_new(crumpled_addr); This one's fine. The overall idea makes sense, but since this is still RFC, and there may still be wordsmithing to do, I'll wait to give R-b until v3.
Eric Blake <eblake@redhat.com> writes: > On 03/30/2017 08:15 AM, Markus Armbruster wrote: > >> However, A few places access the flat QDict directly: >> >> * Most of them access members that are always QString. Correct. >> >> * bdrv_open_inherit() accesses a boolean, carefully. Correct. >> >> * nfs_config() uses a QObject input visitor. Correct only because the >> visited type contains nothing but QStrings. >> >> * nbd_config() and ssh_config() use a QObject input visitor, and the >> visited types contain non-QStrings: InetSocketAddress members >> @numeric, @to, @ipv4, @ipv6. -drive works as long as you don't try >> to use them (they're all optional). @to is ignored anyway. >> >> Reproducer: >> -drive driver=ssh,server.host=h,server.port=22,server.ipv4,path=p >> -drive driver=nbd,server.type=inet,server.data.host=h,server.data.port=22,server.data.ipv4 >> both fail with "Invalid parameter type for 'data.ipv4', expected: boolean" >> >> Add suitable comments to all these places. Mark the buggy ones FIXME. >> >> "Fortunately", -drive's driver-specific options are entirely >> undocumented. >> >> Signed-off-by: Markus Armbruster <armbru@redhat.com> >> --- > >> +++ b/block.c >> @@ -1157,6 +1157,12 @@ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file, >> if (file != NULL) { >> filename = blk_bs(file)->filename; >> } else { >> + /* >> + * Caution: direct use of non-string @options members is >> + * problematic. When they come from -blockdev or blockdev_add, >> + * members are typed according to the QAPI schema, but when >> + * they come from -drive, they're all QString. >> + */ >> filename = qdict_get_try_str(options, "filename"); > > Did we get the latest round of comment tweaking in here? I was > expecting to see something along the lines of: > > "Caution: accessing 'filename' from @options here is safe, but direct > use of any non-string @options members would be problematic. When they > come..." I haven't updated this patch for review, yet. One more reason this is RFC. Forgot to mention in the cover letter, sorry. >> } >> >> @@ -1324,6 +1330,12 @@ static int bdrv_fill_options(QDict **options, const char *filename, >> BlockDriver *drv = NULL; >> Error *local_err = NULL; >> >> + /* >> + * Caution: direct use of non-string @options members is >> + * problematic. When they come from -blockdev or blockdev_add, >> + * members are typed according to the QAPI schema, but when they >> + * come from -drive, they're all QString. >> + */ >> drvname = qdict_get_try_str(*options, "driver"); > > Again, wordsmithing might be nice to call out that 'driver' is safe, but > future additions of other accesses must be careful. Yes. >> @@ -1987,6 +2000,12 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, >> qdict_extract_subqdict(parent_options, &options, bdref_key_dot); >> g_free(bdref_key_dot); >> >> + /* >> + * Caution: direct use of non-string @parent_options members is >> + * problematic. When they come from -blockdev or blockdev_add, >> + * members are typed according to the QAPI schema, but when they >> + * come from -drive, they're all QString. >> + */ >> reference = qdict_get_try_str(parent_options, bdref_key); > > Again, wordsmithing to mention that bdref_key is safe. Yes. >> if (reference || qdict_haskey(options, "file.filename")) { >> backing_filename[0] = '\0'; >> @@ -2059,6 +2078,12 @@ bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key, >> qdict_extract_subqdict(options, &image_options, bdref_key_dot); >> g_free(bdref_key_dot); >> >> + /* >> + * Caution: direct use of non-string @options members is >> + * problematic. When they come from -blockdev or blockdev_add, >> + * members are typed according to the QAPI schema, but when they >> + * come from -drive, they're all QString. >> + */ >> reference = qdict_get_try_str(options, bdref_key); > > Ditto. Yes. >> if (!filename && !reference && !qdict_size(image_options)) { >> if (!allow_none) { >> @@ -2275,8 +2300,11 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, >> } >> >> /* Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags. >> - * FIXME: we're parsing the QDict to avoid having to create a >> - * QemuOpts just for this, but neither option is optimal. */ >> + * Caution: direct use of non-string @options members is >> + * problematic. When they come from -blockdev or blockdev_add, >> + * members are typed according to the QAPI schema, but when they >> + * come from -drive, they're all QString. >> + */ >> if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") && >> !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) { >> flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR); > > Maybe here, the wordsmithing would mention that the extra hoops we jump > through to cover both types is what makes access safe. Yes. >> +++ b/block/nbd.c >> @@ -278,6 +278,14 @@ static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options, Error **errp) >> goto done; >> } >> >> + /* >> + * FIXME .numeric, .to, .ipv4 or .ipv6 don't work with -drive >> + * server.type=inet. .to doesn't matter, it's ignored anyway. >> + * That's because when @options come from -blockdev or >> + * blockdev_add, members are typed according to the QAPI schema, >> + * but when they come from -drive, they're all QString. The >> + * visitor expects the former. >> + */ > > This one is fine. > >> iv = qobject_input_visitor_new(crumpled_addr); >> visit_type_SocketAddress(iv, NULL, &saddr, &local_err); >> if (local_err) { >> diff --git a/block/nfs.c b/block/nfs.c >> index 3f43f6e..42407de 100644 >> --- a/block/nfs.c >> +++ b/block/nfs.c >> @@ -474,6 +474,13 @@ static NFSServer *nfs_config(QDict *options, Error **errp) >> goto out; >> } >> >> + /* >> + * Caution: this works only because all scalar members of >> + * NFSServer are QString in @crumpled_addr. The visitor expects >> + * @crumpled_addr to be typed according to the QAPI scherma. It >> + * is when @options come from -blockdev or blockdev_add. But when >> + * they come from -drive, they're all QString. >> + */ >> iv = qobject_input_visitor_new(crumpled_addr); > > This one is also fine. > >> visit_type_NFSServer(iv, NULL, &server, &local_error); >> if (local_error) { >> diff --git a/block/rbd.c b/block/rbd.c >> index 498322b..b9a9526 100644 >> --- a/block/rbd.c >> +++ b/block/rbd.c >> @@ -384,6 +384,12 @@ static int qemu_rbd_create(const char *filename, QemuOpts *opts, Error **errp) >> goto exit; >> } >> >> + /* >> + * Caution: direct use of non-string @options members is >> + * problematic. When they come from -blockdev or blockdev_add, >> + * members are typed according to the QAPI schema, but when they >> + * come from -drive, they're all QString. > > Here, wordsmithing may be worth mentioning that we are safe because > these are all strings. Yes. >> + */ >> pool = qdict_get_try_str(options, "pool"); >> conf = qdict_get_try_str(options, "conf"); >> clientname = qdict_get_try_str(options, "user"); >> diff --git a/block/ssh.c b/block/ssh.c >> index 278e66f..471ba8a 100644 >> --- a/block/ssh.c >> +++ b/block/ssh.c >> @@ -601,6 +601,14 @@ static InetSocketAddress *ssh_config(QDict *options, Error **errp) >> goto out; >> } >> >> + /* >> + * FIXME .numeric, .to, .ipv4 or .ipv6 don't work with -drive. >> + * .to doesn't matter, it's ignored anyway. >> + * That's because when @options come from -blockdev or >> + * blockdev_add, members are typed according to the QAPI schema, >> + * but when they come from -drive, they're all QString. The >> + * visitor expects the former. >> + */ >> iv = qobject_input_visitor_new(crumpled_addr); > > This one's fine. > > The overall idea makes sense, but since this is still RFC, and there may > still be wordsmithing to do, I'll wait to give R-b until v3. Thanks!
diff --git a/block.c b/block.c index 6e906ec..b3ce23f 100644 --- a/block.c +++ b/block.c @@ -1157,6 +1157,12 @@ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file, if (file != NULL) { filename = blk_bs(file)->filename; } else { + /* + * Caution: direct use of non-string @options members is + * problematic. When they come from -blockdev or blockdev_add, + * members are typed according to the QAPI schema, but when + * they come from -drive, they're all QString. + */ filename = qdict_get_try_str(options, "filename"); } @@ -1324,6 +1330,12 @@ static int bdrv_fill_options(QDict **options, const char *filename, BlockDriver *drv = NULL; Error *local_err = NULL; + /* + * Caution: direct use of non-string @options members is + * problematic. When they come from -blockdev or blockdev_add, + * members are typed according to the QAPI schema, but when they + * come from -drive, they're all QString. + */ drvname = qdict_get_try_str(*options, "driver"); if (drvname) { drv = bdrv_find_format(drvname); @@ -1358,6 +1370,7 @@ static int bdrv_fill_options(QDict **options, const char *filename, } /* Find the right block driver */ + /* Direct use of @options members is problematic, see note above */ filename = qdict_get_try_str(*options, "filename"); if (!drvname && protocol) { @@ -1987,6 +2000,12 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, qdict_extract_subqdict(parent_options, &options, bdref_key_dot); g_free(bdref_key_dot); + /* + * Caution: direct use of non-string @parent_options members is + * problematic. When they come from -blockdev or blockdev_add, + * members are typed according to the QAPI schema, but when they + * come from -drive, they're all QString. + */ reference = qdict_get_try_str(parent_options, bdref_key); if (reference || qdict_haskey(options, "file.filename")) { backing_filename[0] = '\0'; @@ -2059,6 +2078,12 @@ bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key, qdict_extract_subqdict(options, &image_options, bdref_key_dot); g_free(bdref_key_dot); + /* + * Caution: direct use of non-string @options members is + * problematic. When they come from -blockdev or blockdev_add, + * members are typed according to the QAPI schema, but when they + * come from -drive, they're all QString. + */ reference = qdict_get_try_str(options, bdref_key); if (!filename && !reference && !qdict_size(image_options)) { if (!allow_none) { @@ -2275,8 +2300,11 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, } /* Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags. - * FIXME: we're parsing the QDict to avoid having to create a - * QemuOpts just for this, but neither option is optimal. */ + * Caution: direct use of non-string @options members is + * problematic. When they come from -blockdev or blockdev_add, + * members are typed according to the QAPI schema, but when they + * come from -drive, they're all QString. + */ if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") && !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) { flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR); @@ -2298,6 +2326,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, options = qdict_clone_shallow(options); /* Find the right image format driver */ + /* Direct use of @options members is problematic, see note above */ drvname = qdict_get_try_str(options, "driver"); if (drvname) { drv = bdrv_find_format(drvname); @@ -2309,6 +2338,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, assert(drvname || !(flags & BDRV_O_PROTOCOL)); + /* Direct use of @options members is problematic, see note above */ backing = qdict_get_try_str(options, "backing"); if (backing && *backing == '\0') { flags |= BDRV_O_NO_BACKING; @@ -2787,6 +2817,13 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, do { QString *new_obj = qobject_to_qstring(entry->value); const char *new = qstring_get_str(new_obj); + /* + * Caution: direct use of non-string bs->options members is + * problematic. When they come from -blockdev or + * blockdev_add, members are typed according to the QAPI + * schema, but when they come from -drive, they're all + * QString. + */ const char *old = qdict_get_try_str(reopen_state->bs->options, entry->key); diff --git a/block/file-posix.c b/block/file-posix.c index 0841a08..738541e 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -2193,6 +2193,12 @@ static int hdev_open(BlockDriverState *bs, QDict *options, int flags, int ret; #if defined(__APPLE__) && defined(__MACH__) + /* + * Caution: direct use of non-string @options members is + * problematic. When they come from -blockdev or blockdev_add, + * members are typed according to the QAPI schema, but when they + * come from -drive, they're all QString. + */ const char *filename = qdict_get_str(options, "filename"); char bsd_path[MAXPATHLEN] = ""; bool error_occurred = false; diff --git a/block/nbd.c b/block/nbd.c index 36ea617..11e3ba7 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -278,6 +278,14 @@ static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options, Error **errp) goto done; } + /* + * FIXME .numeric, .to, .ipv4 or .ipv6 don't work with -drive + * server.type=inet. .to doesn't matter, it's ignored anyway. + * That's because when @options come from -blockdev or + * blockdev_add, members are typed according to the QAPI schema, + * but when they come from -drive, they're all QString. The + * visitor expects the former. + */ iv = qobject_input_visitor_new(crumpled_addr); visit_type_SocketAddress(iv, NULL, &saddr, &local_err); if (local_err) { diff --git a/block/nfs.c b/block/nfs.c index 3f43f6e..42407de 100644 --- a/block/nfs.c +++ b/block/nfs.c @@ -474,6 +474,13 @@ static NFSServer *nfs_config(QDict *options, Error **errp) goto out; } + /* + * Caution: this works only because all scalar members of + * NFSServer are QString in @crumpled_addr. The visitor expects + * @crumpled_addr to be typed according to the QAPI scherma. It + * is when @options come from -blockdev or blockdev_add. But when + * they come from -drive, they're all QString. + */ iv = qobject_input_visitor_new(crumpled_addr); visit_type_NFSServer(iv, NULL, &server, &local_error); if (local_error) { diff --git a/block/rbd.c b/block/rbd.c index 498322b..b9a9526 100644 --- a/block/rbd.c +++ b/block/rbd.c @@ -384,6 +384,12 @@ static int qemu_rbd_create(const char *filename, QemuOpts *opts, Error **errp) goto exit; } + /* + * Caution: direct use of non-string @options members is + * problematic. When they come from -blockdev or blockdev_add, + * members are typed according to the QAPI schema, but when they + * come from -drive, they're all QString. + */ pool = qdict_get_try_str(options, "pool"); conf = qdict_get_try_str(options, "conf"); clientname = qdict_get_try_str(options, "user"); diff --git a/block/ssh.c b/block/ssh.c index 278e66f..471ba8a 100644 --- a/block/ssh.c +++ b/block/ssh.c @@ -601,6 +601,14 @@ static InetSocketAddress *ssh_config(QDict *options, Error **errp) goto out; } + /* + * FIXME .numeric, .to, .ipv4 or .ipv6 don't work with -drive. + * .to doesn't matter, it's ignored anyway. + * That's because when @options come from -blockdev or + * blockdev_add, members are typed according to the QAPI schema, + * but when they come from -drive, they're all QString. The + * visitor expects the former. + */ iv = qobject_input_visitor_new(crumpled_addr); visit_type_InetSocketAddress(iv, NULL, &inet, &local_error); if (local_error) {
-blockdev and blockdev_add convert their arguments via QObject to BlockdevOptions for qmp_blockdev_add(), which converts them back to QObject, then to a flattened QDict. The QDict's members are typed according to the QAPI schema. -drive converts its argument via QemuOpts to a (flat) QDict. This QDict's members are all QString. Thus, the QType of a flat QDict member depends on whether it comes from -drive or -blockdev/blockdev_add, except when the QAPI type maps to QString, which is the case for 'str' and enumeration types. The block layer core extracts generic configuration from the flat QDict, and the block driver extracts driver-specific configuration. Both commonly do so by converting (parts of) the flat QDict to QemuOpts, which turns all values into strings. Not exactly elegant, but correct. However, A few places access the flat QDict directly: * Most of them access members that are always QString. Correct. * bdrv_open_inherit() accesses a boolean, carefully. Correct. * nfs_config() uses a QObject input visitor. Correct only because the visited type contains nothing but QStrings. * nbd_config() and ssh_config() use a QObject input visitor, and the visited types contain non-QStrings: InetSocketAddress members @numeric, @to, @ipv4, @ipv6. -drive works as long as you don't try to use them (they're all optional). @to is ignored anyway. Reproducer: -drive driver=ssh,server.host=h,server.port=22,server.ipv4,path=p -drive driver=nbd,server.type=inet,server.data.host=h,server.data.port=22,server.data.ipv4 both fail with "Invalid parameter type for 'data.ipv4', expected: boolean" Add suitable comments to all these places. Mark the buggy ones FIXME. "Fortunately", -drive's driver-specific options are entirely undocumented. Signed-off-by: Markus Armbruster <armbru@redhat.com> --- block.c | 41 +++++++++++++++++++++++++++++++++++++++-- block/file-posix.c | 6 ++++++ block/nbd.c | 8 ++++++++ block/nfs.c | 7 +++++++ block/rbd.c | 6 ++++++ block/ssh.c | 8 ++++++++ 6 files changed, 74 insertions(+), 2 deletions(-)