[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/9] libxl: disks: Make LIBXL_DISK_BACKEND_UNKNOWN work
Ian Campbell writes ("Re: [Xen-devel] [PATCH 1/9] libxl: disks: Make LIBXL_DISK_BACKEND_UNKNOWN work"): > I think this should be treated the same as you did above, by adding an > explicit fallback before the switch statement, for clarity. OK. This results in two copies of the same comment. Really we should have a common function for figuring out the correct backend, but this at least makes things no worse. Ian. commit ee4720b0f9b15be152b10656b9b3e13b83be6c55 Author: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> Date: Fri May 6 09:02:02 2011 +0100 libxl: disks: Make LIBXL_DISK_BACKEND_UNKNOWN work libxl callers should not be required to specify the backend if they don't want to. So LIBXL_DISK_BACKEND_UNKNOWN should instruct libxl to choose the backend for itself. For now, we do this by simply treating it the same as BACKEND_TAP, which itself falls back to other methods. More thorough fixes for the disk handling will follow. Signed-off-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c index c21cfe7..a36de58 100644 --- a/tools/libxl/libxl.c +++ b/tools/libxl/libxl.c @@ -991,6 +991,21 @@ int libxl_device_disk_add(libxl_ctx *ctx, uint32_t domid, libxl_device_disk *dis device.domid = domid; device.kind = DEVICE_VBD; + + /* + * Fixing the incoming backend type to try to decide on which + * backend to use. Unfortunately at the moment this code is + * utterly broken, but it more or less works. + */ + + /* + * Backend type UNKNOWN should mean "caller does not want to specify", + * not "break pointlessely". (Callers should not be required to + * specify the backend if they don't want to.) + */ + if (disk->backend == LIBXL_DISK_BACKEND_UNKNOWN) + disk->backend = LIBXL_DISK_BACKEND_TAP; + /* If blktap is not available then fallback to qdisk */ if (disk->backend == LIBXL_DISK_BACKEND_TAP && !libxl__blktap_enabled(&gc)) disk->backend = LIBXL_DISK_BACKEND_QDISK; @@ -1126,6 +1141,20 @@ char * libxl_device_disk_local_attach(libxl_ctx *ctx, libxl_device_disk *disk) char *dev = NULL; char *ret = NULL; + /* + * Fixing the incoming backend type to try to decide on which + * backend to use. Unfortunately at the moment this code is + * utterly broken, but it more or less works. + */ + + /* + * Backend type UNKNOWN should mean "caller does not want to specify", + * not "break pointlessely". (Callers should not be required to + * specify the backend if they don't want to.) + */ + if (disk->backend == LIBXL_DISK_BACKEND_UNKNOWN) + disk->backend = LIBXL_DISK_BACKEND_TAP; + switch (disk->backend) { case LIBXL_DISK_BACKEND_PHY: if (disk->format != LIBXL_DISK_FORMAT_RAW) { @@ -1175,7 +1204,6 @@ char * libxl_device_disk_local_attach(libxl_ctx *ctx, libxl_device_disk *disk) disk->pdev_path); dev = disk->pdev_path; break; - case LIBXL_DISK_BACKEND_UNKNOWN: default: LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unrecognized disk backend " "type: %d", disk->backend); _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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