Re: [Qemu-devel] [PATCH 3/7] block: raw-posix image file reopen

[Eric Blake]

On 08/30/2012 11:47 AM, Jeff Cody wrote:
> This is derived from the Supriya Kannery's reopen patches.
> 
> This contains the raw-posix driver changes for the bdrv_reopen_*
> functions.  All changes are staged into a temporary scratch buffer
> during the prepare() stage, and copied over to the live structure
> during commit().  Upon abort(), all changes are abandoned, and the
> live structures are unmodified.
> 
> The _prepare() will create an extra fd - either by means of a dup,
> if possible, or opening a new fd if not (for instance, access
> control changes).  Upon _commit(), the original fd is closed and
> the new fd is used.  Upon _abort(), the duplicate/new fd is closed.
> 

> +    if ((raw_s->open_flags & ~fcntl_flags) == (s->open_flags & 
> ~fcntl_flags)) {
> +        /* dup the original fd */
> +        /* TODO: use qemu fcntl wrapper */
> +        raw_s->fd = fcntl(s->fd, F_DUPFD_CLOEXEC, 0);

I assume this TODO has to be fixed to allow compilation on systems that
lack F_DUPFD_CLOEXEC.

> +        if (raw_s->fd == -1) {
> +            ret = -1;
> +            goto error;
> +        }
> +        ret = fcntl_setfl(raw_s->fd, raw_s->open_flags);
> +    } else {
> +        raw_s->fd = qemu_open(state->bs->filename, raw_s->open_flags, 0644);

Is raw_s->open_flags every going to contain O_CREAT, or is the 0644 mode
argument spurious?

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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