Re: [Qemu-devel] [v9 Patch 6/6]Qemu: raw posix implementation of reopen functions

[Stefan Hajnoczi]

On Fri, Nov 11, 2011 at 6:48 AM, Supriya Kannery
<address@hidden> wrote:
> +static int raw_reopen_prepare(BlockDriverState *bs, BDRVReopenState **prs,
> +                              int flags)
> +{
> +    BDRVRawReopenState *raw_rs = g_malloc0(sizeof(BDRVRawReopenState));
> +    BDRVRawState *s = bs->opaque;
> +    int ret = 0;
> +
> +    raw_rs->reopen_state.reopen_flags = s->open_flags;
> +    raw_rs->reopen_state.bs = bs;
> +    raw_rs->reopen_fd = -1;
> +    *prs = &(raw_rs->reopen_state);
> +
> +    /* Flags that can be set using fcntl */
> +    int fcntl_flags = BDRV_O_NOCACHE;
> +
> +    if ((bs->open_flags & ~fcntl_flags) == (flags & ~fcntl_flags)) {
> +        raw_rs->reopen_fd = dup(s->fd);
> +        if (raw_rs->reopen_fd <= 0) {
> +            return -1;

return -errno;

> +        }
> +        if ((flags & BDRV_O_NOCACHE)) {
> +            raw_rs->reopen_state.reopen_flags |= O_DIRECT;
> +        } else {
> +            raw_rs->reopen_state.reopen_flags &= ~O_DIRECT;
> +        }
> +        ret = fcntl_setfl(raw_rs->reopen_fd, 
> raw_rs->reopen_state.reopen_flags);

I wonder if this works on Solaris, FreeBSD, etc?

Perhaps there needs to be a fallback to the missing "else" case below...

> +    } else {
> +
> +        /* TBD: Handle O_DSYNC and other flags. For now return error */
> +        ret = -1;

...and this needs to be implemented.

> +    }
> +    return ret;
> +}

Stefan