Re: [Qemu-devel] [PATCH 5/5] drive_open: Add invalidate option for block devices

[Blue Swirl]

On Tue, Jan 4, 2011 at 2:33 PM, Juan Quintela <address@hidden> wrote:
> Linux allows to invalidate block devices.  This is needed for the incoming
> migration part.
>
> Signed-off-by: Juan Quintela <address@hidden>
> ---
>  block.h           |    2 ++
>  block/raw-posix.c |   24 ++++++++++++++++++++++++
>  blockdev.c        |    9 +++++----
>  3 files changed, 31 insertions(+), 4 deletions(-)
>
> diff --git a/block.h b/block.h
> index f923add..5ac96a5 100644
> --- a/block.h
> +++ b/block.h
> @@ -34,6 +34,8 @@ typedef struct QEMUSnapshotInfo {
>  #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread 
> pool */
>  #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
>  #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
> +#define BDRV_O_INVALIDATE  0x0400 /* invalidate buffer cache for this device.
> +                                     re-read things from server */
>
>  #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_CACHE_WB | 
> BDRV_O_NO_FLUSH)
>
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 6b72470..9439cf1 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -51,6 +51,7 @@
>  #include <sys/param.h>
>  #include <linux/cdrom.h>
>  #include <linux/fd.h>
> +#include <linux/fs.h>
>  #endif
>  #if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
>  #include <signal.h>
> @@ -168,6 +169,29 @@ static int raw_open_common(BlockDriverState *bs, const 
> char *filename,
>     s->fd = fd;
>     s->aligned_buf = NULL;
>
> +#ifdef __linux__
> +    if ((bdrv_flags & BDRV_O_INVALIDATE)) {
> +        struct stat buf;
> +        int res;
> +
> +        res = fstat(fd, &buf);
> +
> +        if (res < 0) {
> +            return -errno;
> +        }
> +
> +        if (S_ISBLK(buf.st_mode)) {
> +            printf("we are in a block device: %s\n", filename);

Leftover debugging?