Am 12.06.2014 um 14:08 hat Benoît Canet geschrieben:
> The Wednesday 11 Jun 2014 à 16:04:55 (+0200), Kevin Wolf wrote :
> > The idea of bdrv_fill_options() is to convert every parameter for
> > opening images, in particular the filename and flags, to entries in the
> > options QDict.
> >
> > This patch starts with moving the filename parsing and driver probing
> > part from bdrv_file_open() to the new function.
> >
> > Signed-off-by: Kevin Wolf <kw...@redhat.com>
> > ---
> > block.c | 116
> > ++++++++++++++++++++++++++++++++++++++++------------------------
> > 1 file changed, 73 insertions(+), 43 deletions(-)
> >
> > diff --git a/block.c b/block.c
> > index 17f763d..c5707e8 100644
> > --- a/block.c
> > +++ b/block.c
> > @@ -1007,77 +1007,107 @@ free_and_fail:
> > }
> >
> > /*
> > - * Opens a file using a protocol (file, host_device, nbd, ...)
> > - *
> > - * options is an indirect pointer to a QDict of options to pass to the
> > block
> > - * drivers, or pointer to NULL for an empty set of options. If this
> > function
> > - * takes ownership of the QDict reference, it will set *options to NULL;
> > - * otherwise, it will contain unused/unrecognized options after this
> > function
> > - * returns. Then, the caller is responsible for freeing it. If it intends
> > to
> > - * reuse the QDict, QINCREF() should be called beforehand.
> > + * Fills in default options for opening images and converts the legacy
> > + * filename/flags pair to option QDict entries.
> > */
> > -static int bdrv_file_open(BlockDriverState *bs, const char *filename,
> > - QDict **options, int flags, Error **errp)
> > +static int bdrv_fill_options(QDict **options, const char *filename,
> > + Error **errp)
> > {
> > - BlockDriver *drv;
> > const char *drvname;
> > bool parse_filename = false;
> > Error *local_err = NULL;
> > - int ret;
> > + BlockDriver *drv;
> >
> > /* Fetch the file name from the options QDict if necessary */
> > - if (!filename) {
> > - filename = qdict_get_try_str(*options, "filename");
> > - } else if (filename && !qdict_haskey(*options, "filename")) {
> > - qdict_put(*options, "filename", qstring_from_str(filename));
> > - parse_filename = true;
> > - } else {
> > - error_setg(errp, "Can't specify 'file' and 'filename' options at
> > the "
> > - "same time");
> > - ret = -EINVAL;
> > - goto fail;
> > + if (filename) {
> > + if (filename && !qdict_haskey(*options, "filename")) {
>
> The inner filename testing is redundant.
Will fix.
> > + qdict_put(*options, "filename", qstring_from_str(filename));
> > + parse_filename = true;
> > + } else {
> > + error_setg(errp, "Can't specify 'file' and 'filename' options
> > at "
> > + "the same time");
> > + return -EINVAL;
> > + }
> > }
> >
> > /* Find the right block driver */
> > + filename = qdict_get_try_str(*options, "filename");
> > drvname = qdict_get_try_str(*options, "driver");
> > - if (drvname) {
> > - drv = bdrv_find_format(drvname);
> > - if (!drv) {
> > - error_setg(errp, "Unknown driver '%s'", drvname);
> > - }
> > - qdict_del(*options, "driver");
> > - } else if (filename) {
> > - drv = bdrv_find_protocol(filename, parse_filename);
> > - if (!drv) {
> > - error_setg(errp, "Unknown protocol");
> > +
> > + if (!drvname) {
> > + if (filename) {
> > + drv = bdrv_find_protocol(filename, parse_filename);
> > + if (!drv) {
> > + error_setg(errp, "Unknown protocol");
> > + return -EINVAL;
> > + }
> > +
> > + drvname = drv->format_name;
> > + qdict_put(*options, "driver", qstring_from_str(drvname));
> > + } else {
> > + error_setg(errp, "Must specify either driver or file");
>
> Isn't it "Must specify either driver or _filename_ ?
This is only code motion, but changing it in a separate patch would make
sense, I guess.
> > + return -EINVAL;
> > }
> > - } else {
> > - error_setg(errp, "Must specify either driver or file");
> > - drv = NULL;
> > }
> >
> > + drv = bdrv_find_format(drvname);
> > if (!drv) {
> > - /* errp has been set already */
> > - ret = -ENOENT;
> > - goto fail;
> > + error_setg(errp, "Unknown driver '%s'", drvname);
> > + return -ENOENT;
> > }
> >
> > - /* Parse the filename and open it */
> > + /* Driver-specific filename parsing */
> > if (drv->bdrv_parse_filename && parse_filename) {
> > drv->bdrv_parse_filename(filename, *options, &local_err);
> > if (local_err) {
> > error_propagate(errp, local_err);
> > - ret = -EINVAL;
> > - goto fail;
> > + return -EINVAL;
> > }
> >
> > if (!drv->bdrv_needs_filename) {
> > qdict_del(*options, "filename");
> > - } else {
> > - filename = qdict_get_str(*options, "filename");
> > }
> > }
> >
> > + return 0;
> > +}
> > +
> > +/*
> > + * Opens a file using a protocol (file, host_device, nbd, ...)
> > + *
> > + * options is an indirect pointer to a QDict of options to pass to the
> > block
> > + * drivers, or pointer to NULL for an empty set of options. If this
> > function
> > + * takes ownership of the QDict reference, it will set *options to NULL;
> > + * otherwise, it will contain unused/unrecognized options after this
> > function
> > + * returns. Then, the caller is responsible for freeing it. If it intends
> > to
> > + * reuse the QDict, QINCREF() should be called beforehand.
> > + */
> > +static int bdrv_file_open(BlockDriverState *bs, const char *filename,
> > + QDict **options, int flags, Error **errp)
> > +{
> > + BlockDriver *drv;
> > + const char *drvname;
> > + Error *local_err = NULL;
> > + int ret;
> > +
> > + ret = bdrv_fill_options(options, filename, &local_err);
> > + if (local_err) {
> > + error_propagate(errp, local_err);
> > + return ret;
> Why not goto fail for consistency with the rest of the function ?
Okay. Rather pointless and the function will be gone at the end of the
series, but more consistent indeed.
> > + }
> > +
> > + filename = qdict_get_try_str(*options, "filename");
> > + drvname = qdict_get_str(*options, "driver");
> > +
> > + drv = bdrv_find_format(drvname);
> > + if (!drv) {
> > + error_setg(errp, "Unknown driver '%s'", drvname);
> > + ret = -ENOENT;
> > + goto fail;
> > + }
> > + qdict_del(*options, "driver");
> > +
> > + /* Open the file */
> > if (!drv->bdrv_file_open) {
>
> Don't we need:
> qdict_del(*options, "filename");
> Here so bdrv_open don't see an extra filename option ?
I think it doesn't matter because bdrv_open() would put it back again.
Do you have an example where it makes a difference?
> > ret = bdrv_open(&bs, filename, NULL, *options, flags, drv,
> > &local_err);
> > *options = NULL;
Kevin
