[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 2/2] 4.1.2 blktap2 cleanup fixes.
--------------------------------------------------------------------------- The following patch when applied on top of: libxl: attempt to cleanup tapdisk processes on disk backend destroy. Establishes correct cleanup behavior for blktap devices. This patch implements the release of the backend device before calling for the destruction of the userspace component of the blktap device. Without this patch the kernel xen-blkback driver deadlocks with the blktap2 user control plane until the IPC channel is terminated by the timeout on the select() call. This results in a noticeable delay in the termination of the guest and causes the blktap minor number which had been allocated to be orphaned. Signed-off-by: Greg Wettstein <greg@xxxxxxxxxxxx> diff -r b184698e0893 tools/libxl/libxl_blktap2.c --- a/tools/libxl/libxl_blktap2.c Tue Nov 06 19:53:48 2012 -0600 +++ b/tools/libxl/libxl_blktap2.c Tue Nov 06 19:54:23 2012 -0600 @@ -59,6 +59,7 @@ void libxl__device_destroy_tapdisk(libxl char *path, *params, *type, *disk; int err; tap_list_t tap; + libxl_ctx *ctx = libxl__gc_owner(gc); path = libxl__sprintf(gc, "%s/tapdisk-params", be_path); if (!path) return; @@ -75,5 +76,11 @@ void libxl__device_destroy_tapdisk(libxl err = tap_ctl_find(type, disk, &tap); if (err < 0) return; + /* + * Remove the instance of the backend device to avoid a deadlock with the + * removal of the tap device. + */ + xs_rm(ctx->xsh, XBT_NULL, be_path); + tap_ctl_destroy(tap.id, tap.minor); } diff -r b184698e0893 tools/libxl/libxl_device.c --- a/tools/libxl/libxl_device.c Tue Nov 06 19:53:48 2012 -0600 +++ b/tools/libxl/libxl_device.c Tue Nov 06 19:54:23 2012 -0600 @@ -250,8 +250,7 @@ int libxl__device_destroy(libxl_ctx *ctx if (!state) goto out; if (atoi(state) != 4) { - libxl__device_destroy_tapdisk(&gc, be_path); - xs_rm(ctx->xsh, XBT_NULL, be_path); + libxl__device_destroy_tapdisk(&gc, be_path); goto out; } --------------------------------------------------------------------------- As always, Dr. G.W. Wettstein, Ph.D. Enjellic Systems Development, LLC. 4206 N. 19th Ave. Specializing in information infra-structure Fargo, ND 58102 development. PH: 701-281-1686 FAX: 701-281-3949 EMAIL: greg@xxxxxxxxxxxx ------------------------------------------------------------------------------ "Fungus doesn't take a vacation." -- Rob Pike _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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