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block: Purify .bdrv_refresh_filename()

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Currently, BlockDriver.bdrv_refresh_filename() is supposed to both
refresh the filename (BDS.exact_filename) and set BDS.full_open_options.
Now that we have generic code in the central bdrv_refresh_filename() for
creating BDS.full_open_options, we can drop the latter part from all
BlockDriver.bdrv_refresh_filename() implementations.

This also means that we can drop all of the existing default code for
this from the global bdrv_refresh_filename() itself.

Furthermore, we now have to call BlockDriver.bdrv_refresh_filename()
after having set BDS.full_open_options, because the block driver's
implementation should now be allowed to depend on BDS.full_open_options
being set correctly.

Finally, with this patch we can drop the @options parameter from
BlockDriver.bdrv_refresh_filename(); also, add a comment on this
function's purpose in block/block_int.h while touching its interface.

This completely obsoletes blklogwrite's implementation of
.bdrv_refresh_filename().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190201192935.18394-25-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Max Reitz
2019-02-01 20:29:28 +01:00
parent 97e2f021f8
commit 998b3a1e5a
14 changed files with 79 additions and 289 deletions
Download Patch File Download Diff File Expand all files Collapse all files

131
block.c
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@@ -5621,33 +5621,6 @@ static bool append_strong_runtime_options(QDict *d, BlockDriverState *bs)
return found_any;
}
static bool append_open_options(QDict *d, BlockDriverState *bs)
{
const QDictEntry *entry;
QemuOptDesc *desc;
bool found_any = false;
for (entry = qdict_first(bs->options); entry;
entry = qdict_next(bs->options, entry))
{
/* Exclude all non-driver-specific options */
for (desc = bdrv_runtime_opts.desc; desc->name; desc++) {
if (!strcmp(qdict_entry_key(entry), desc->name)) {
break;
}
}
if (desc->name) {
continue;
}
qdict_put_obj(d, qdict_entry_key(entry),
qobject_ref(qdict_entry_value(entry)));
found_any = true;
}
return found_any;
}
/* Note: This function may return false positives; it may return true
* even if opening the backing file specified by bs's image header
* would result in exactly bs->backing. */
@@ -5681,6 +5654,8 @@ void bdrv_refresh_filename(BlockDriverState *bs)
BdrvChild *child;
QDict *opts;
bool backing_overridden;
bool generate_json_filename; /* Whether our default implementation should
fill exact_filename (false) or not (true) */
if (!drv) {
return;
@@ -5716,90 +5691,10 @@ void bdrv_refresh_filename(BlockDriverState *bs)
backing_overridden = false;
}
if (drv->bdrv_refresh_filename) {
/* Obsolete information is of no use here, so drop the old file name
* information before refreshing it */
bs->exact_filename[0] = '\0';
if (bs->full_open_options) {
qobject_unref(bs->full_open_options);
bs->full_open_options = NULL;
}
opts = qdict_new();
append_open_options(opts, bs);
drv->bdrv_refresh_filename(bs, opts);
qobject_unref(opts);
} else if (bs->file) {
/* Try to reconstruct valid information from the underlying file */
bool has_open_options;
bs->exact_filename[0] = '\0';
if (bs->full_open_options) {
qobject_unref(bs->full_open_options);
bs->full_open_options = NULL;
}
opts = qdict_new();
has_open_options = append_open_options(opts, bs);
has_open_options |= backing_overridden;
/* If no specific options have been given for this BDS, the filename of
* the underlying file should suffice for this one as well */
if (bs->file->bs->exact_filename[0] && !has_open_options) {
strcpy(bs->exact_filename, bs->file->bs->exact_filename);
}
/* Reconstructing the full options QDict is simple for most format block
* drivers, as long as the full options are known for the underlying
* file BDS. The full options QDict of that file BDS should somehow
* contain a representation of the filename, therefore the following
* suffices without querying the (exact_)filename of this BDS. */
if (bs->file->bs->full_open_options &&
(!bs->backing || bs->backing->bs->full_open_options))
{
qdict_put_str(opts, "driver", drv->format_name);
qdict_put(opts, "file",
qobject_ref(bs->file->bs->full_open_options));
if (bs->backing) {
qdict_put(opts, "backing",
qobject_ref(bs->backing->bs->full_open_options));
} else if (backing_overridden) {
qdict_put_null(opts, "backing");
}
bs->full_open_options = opts;
} else {
qobject_unref(opts);
}
} else if (!bs->full_open_options && qdict_size(bs->options)) {
/* There is no underlying file BDS (at least referenced by BDS.file),
* so the full options QDict should be equal to the options given
* specifically for this block device when it was opened (plus the
* driver specification).
* Because those options don't change, there is no need to update
* full_open_options when it's already set. */
opts = qdict_new();
append_open_options(opts, bs);
qdict_put_str(opts, "driver", drv->format_name);
if (bs->exact_filename[0]) {
/* This may not work for all block protocol drivers (some may
* require this filename to be parsed), but we have to find some
* default solution here, so just include it. If some block driver
* does not support pure options without any filename at all or
* needs some special format of the options QDict, it needs to
* implement the driver-specific bdrv_refresh_filename() function.
*/
qdict_put_str(opts, "filename", bs->exact_filename);
}
bs->full_open_options = opts;
}
/* Gather the options QDict */
opts = qdict_new();
append_strong_runtime_options(opts, bs);
generate_json_filename = append_strong_runtime_options(opts, bs);
generate_json_filename |= backing_overridden;
if (drv->bdrv_gather_child_options) {
/* Some block drivers may not want to present all of their children's
@@ -5825,6 +5720,24 @@ void bdrv_refresh_filename(BlockDriverState *bs)
qobject_unref(bs->full_open_options);
bs->full_open_options = opts;
if (drv->bdrv_refresh_filename) {
/* Obsolete information is of no use here, so drop the old file name
* information before refreshing it */
bs->exact_filename[0] = '\0';
drv->bdrv_refresh_filename(bs);
} else if (bs->file) {
/* Try to reconstruct valid information from the underlying file */
bs->exact_filename[0] = '\0';
/* If no specific options have been given for this BDS, the filename of
* the underlying file should suffice for this one as well */
if (bs->file->bs->exact_filename[0] && !generate_json_filename) {
strcpy(bs->exact_filename, bs->file->bs->exact_filename);
}
}
if (bs->exact_filename[0]) {
pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
} else {