From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Wolf Subject: [PATCH 4/4] blktap: Move error signaling to blktapctrl Date: Thu, 12 Mar 2009 19:33:58 +0100 Message-ID: <49B95596.9000406@suse.de> References: <49B9544C.4030006@suse.de> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------010701080909030302030307" Return-path: In-Reply-To: <49B9544C.4030006@suse.de> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "xen-devel@lists.xensource.com" Cc: Jim Fehlig List-Id: xen-devel@lists.xenproject.org This is a multi-part message in MIME format. --------------010701080909030302030307 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Until now the udev script for blktap devices needs to decide if to signal success or failure to xend. As this script runs completely independent of blktapctrl and tapdisk/ioemu which do the real work, the udev script can't even theoretically know if tapdisk is happy. This patch removes the udev script and replaces its checks by new ones in libblktap. Signed-off-by: Kevin Wolf --------------010701080909030302030307 Content-Type: text/x-patch; name="blktap-error-handling.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="blktap-error-handling.patch" blktap: Move error signaling to blktapctrl Until now the udev script for blktap devices needs to decide if to signal success or failure to xend. As this script runs completely independent of blktapctrl and tapdisk/ioemu which do the real work, the udev script can't even theoretically know if tapdisk is happy. This patch removes the udev script and replaces its checks by new ones in libblktap. Signed-off-by: Kevin Wolf Index: xen-unstable.hg/tools/blktap/drivers/blktapctrl.c =================================================================== --- xen-unstable.hg.orig/tools/blktap/drivers/blktapctrl.c +++ xen-unstable.hg/tools/blktap/drivers/blktapctrl.c @@ -659,9 +659,6 @@ static int blktapctrl_new_blkif(blkif_t DPRINTF("Received a poll for a new vbd\n"); if ( ((blk=blkif->info) != NULL) && (blk->params != NULL) ) { - if (blktap_interface_create(ctlfd, &major, &minor, blkif) < 0) - return -1; - if (test_path(blk->params, &ptr, &type, &exist, &use_ioemu) != 0) { DPRINTF("Error in blktap device string(%s).\n", blk->params); @@ -685,10 +682,6 @@ static int blktapctrl_new_blkif(blkif_t blkif->fds[WRITE] = exist->fds[WRITE]; } - add_disktype(blkif, type); - blkif->major = major; - blkif->minor = minor; - image = (image_t *)malloc(sizeof(image_t)); blkif->prv = (void *)image; blkif->ops = &tapdisk_ops; @@ -712,11 +705,18 @@ static int blktapctrl_new_blkif(blkif_t goto fail; } + if (blktap_interface_create(ctlfd, &major, &minor, blkif) < 0) + return -1; + + blkif->major = major; + blkif->minor = minor; + + add_disktype(blkif, type); + } else return -1; return 0; fail: - ioctl(ctlfd, BLKTAP_IOCTL_FREEINTF, minor); return -EINVAL; } Index: xen-unstable.hg/tools/blktap/lib/xenbus.c =================================================================== --- xen-unstable.hg.orig/tools/blktap/lib/xenbus.c +++ xen-unstable.hg/tools/blktap/lib/xenbus.c @@ -48,6 +48,7 @@ #include #include #include +#include #include "blktaplib.h" #include "list.h" #include "xs_api.h" @@ -149,6 +150,137 @@ static int backend_remove(struct xs_hand return 0; } +static int check_sharing(struct xs_handle *h, struct backend_info *be) +{ + char *dom_uuid; + char *cur_dom_uuid; + char *path; + char *mode; + char *params; + char **domains; + char **devices; + int i, j; + unsigned int num_dom, num_dev; + blkif_info_t *info; + int ret = 0; + + /* If the mode contains '!' or doesn't contain 'w' don't check anything */ + xs_gather(h, be->backpath, "mode", NULL, &mode, NULL); + if (strchr(mode, '!')) + goto out; + if (strchr(mode, 'w') == NULL) + goto out; + + /* Get the UUID of the domain we want to attach to */ + if (asprintf(&path, "/local/domain/%ld", be->frontend_id) == -1) + goto fail; + xs_gather(h, path, "vm", NULL, &dom_uuid, NULL); + free(path); + + /* Iterate through the devices of all VMs */ + domains = xs_directory(h, XBT_NULL, "backend/tap", &num_dom); + if (domains == NULL) + num_dom = 0; + + for (i = 0; !ret && (i < num_dom); i++) { + + /* If it's the same VM, no action needed */ + if (asprintf(&path, "/local/domain/%s", domains[i]) == -1) { + ret = -1; + break; + } + xs_gather(h, path, "vm", NULL, &cur_dom_uuid, NULL); + free(path); + + if (!strcmp(cur_dom_uuid, dom_uuid)) { + free(cur_dom_uuid); + continue; + } + + /* Check the devices */ + if (asprintf(&path, "backend/tap/%s", domains[i]) == -1) { + ret = -1; + free(cur_dom_uuid); + break; + } + devices = xs_directory(h, XBT_NULL, path, &num_dev); + if (devices == NULL) + num_dev = 0; + free(path); + + for (j = 0; !ret && (j < num_dev); j++) { + if (asprintf(&path, "backend/tap/%s/%s", domains[i], devices[j]) == -1) { + ret = -1; + break; + } + xs_gather(h, path, "params", NULL, ¶ms, NULL); + free(path); + + info = be->blkif->info; + if (strcmp(params, info->params)) { + ret = -1; + } + + free(params); + } + + free(cur_dom_uuid); + free(devices); + } + free(domains); + free(dom_uuid); + goto out; + +fail: + ret = -1; +out: + free(mode); + return ret; +} + +static int check_image(struct xs_handle *h, struct backend_info *be, + const char** errmsg) +{ + const char *tmp; + const char *path; + int mode; + blkif_t *blkif = be->blkif; + blkif_info_t *info = blkif->info; + + /* Strip off the image type */ + path = info->params; + + if (!strncmp(path, "tapdisk:", strlen("tapdisk:"))) { + path += strlen("tapdisk:"); + } else if (!strncmp(path, "ioemu:", strlen("ioemu:"))) { + path += strlen("ioemu:"); + } + + tmp = strchr(path, ':'); + if (tmp != NULL) + path = tmp + 1; + + /* Check if the image exists and access is permitted */ + mode = R_OK; + if (!be->readonly) + mode |= W_OK; + if (access(path, mode)) { + if (errno == ENOENT) + *errmsg = "File not found."; + else + *errmsg = "Insufficient file permissions."; + return -1; + } + + /* Check that the image is not attached to a different VM */ + if (check_sharing(h, be)) { + *errmsg = "File already in use by other domain"; + return -1; + } + + return 0; +} + static void ueblktap_setup(struct xs_handle *h, char *bepath) { struct backend_info *be; @@ -156,6 +288,7 @@ static void ueblktap_setup(struct xs_han int len, er, deverr; long int pdev = 0, handle; blkif_info_t *blk; + const char* errmsg = NULL; be = be_lookup_be(bepath); if (be == NULL) @@ -211,6 +344,9 @@ static void ueblktap_setup(struct xs_han be->pdev = pdev; } + if (check_image(h, be, &errmsg)) + goto fail; + er = blkif_init(be->blkif, handle, be->pdev, be->readonly); if (er != 0) { DPRINTF("Unable to open device %s\n",blk->params); @@ -246,12 +382,21 @@ static void ueblktap_setup(struct xs_han } be->blkif->state = CONNECTED; + xs_printf(h, be->backpath, "hotplug-status", "connected"); + DPRINTF("[SETUP] Complete\n\n"); goto close; fail: - if ( (be != NULL) && (be->blkif != NULL) ) + if (be) { + if (errmsg == NULL) + errmsg = "Setting up the backend failed. See the log " + "files in /var/log/xen/ for details."; + xs_printf(h, be->backpath, "hotplug-error", errmsg); + xs_printf(h, be->backpath, "hotplug-status", "error"); + backend_remove(h, be); + } close: if (path) free(path); @@ -286,7 +431,8 @@ static void ueblktap_probe(struct xs_han len = strsep_len(bepath, '/', 7); if (len < 0) goto free_be; - bepath[len] = '\0'; + if (bepath[len] != '\0') + goto free_be; be = malloc(sizeof(*be)); if (!be) { Index: xen-unstable.hg/tools/hotplug/Linux/xen-backend.rules =================================================================== --- xen-unstable.hg.orig/tools/hotplug/Linux/xen-backend.rules +++ xen-unstable.hg/tools/hotplug/Linux/xen-backend.rules @@ -1,4 +1,3 @@ -SUBSYSTEM=="xen-backend", KERNEL=="tap*", RUN+="/etc/xen/scripts/blktap $env{ACTION}" SUBSYSTEM=="xen-backend", KERNEL=="vbd*", RUN+="/etc/xen/scripts/block $env{ACTION}" SUBSYSTEM=="xen-backend", KERNEL=="vtpm*", RUN+="/etc/xen/scripts/vtpm $env{ACTION}" SUBSYSTEM=="xen-backend", KERNEL=="vif*", ACTION=="online", RUN+="$env{script} online" Index: xen-unstable.hg/tools/hotplug/Linux/blktap =================================================================== --- xen-unstable.hg.orig/tools/hotplug/Linux/blktap +++ /dev/null @@ -1,93 +0,0 @@ -#!/bin/bash - -# Copyright (c) 2005, XenSource Ltd. - -dir=$(dirname "$0") -. "$dir/xen-hotplug-common.sh" -. "$dir/block-common.sh" - -findCommand "$@" - -## -# check_blktap_sharing file mode -# -# Perform the sharing check for the given blktap and mode. -# -check_blktap_sharing() -{ - local file="$1" - local mode="$2" - - local base_path="$XENBUS_BASE_PATH/$XENBUS_TYPE" - for dom in $(xenstore-list "$base_path") - do - for dev in $(xenstore-list "$base_path/$dom") - do - params=$(xenstore_read "$base_path/$dom/$dev/params" | cut -d: -f2) - if [ "$file" = "$params" ] - then - - if [ "$mode" = 'w' ] - then - if ! same_vm "$dom" - then - echo 'guest' - return - fi - else - local m=$(xenstore_read "$base_path/$dom/$dev/mode") - m=$(canonicalise_mode "$m") - - if [ "$m" = 'w' ] - then - if ! same_vm "$dom" - then - echo 'guest' - return - fi - fi - fi - fi - done - done - - echo 'ok' -} - - -t=$(xenstore_read_default "$XENBUS_PATH/type" 'MISSING') -if [ -n "$t" ] -then - p=$(xenstore_read "$XENBUS_PATH/params") - # if we have a ':', chew from head including : - if echo $p | grep -q \: - then - p=${p#*:} - fi -fi -# some versions of readlink cannot be passed a regular file -if [ -L "$p" ]; then - file=$(readlink -f "$p") || fatal "$p link does not exist." -else - file="$p" -fi - -if [ "$command" = 'add' ] -then - [ -e "$file" ] || { fatal $file does not exist; } - - FRONTEND_ID=$(xenstore_read "$XENBUS_PATH/frontend-id") - FRONTEND_UUID=$(xenstore_read "/local/domain/$FRONTEND_ID/vm") - mode=$(xenstore_read "$XENBUS_PATH/mode") - mode=$(canonicalise_mode "$mode") - - if [ "$mode" != '!' ] - then - result=$(check_blktap_sharing "$file" "$mode") - [ "$result" = 'ok' ] || ebusy "$file already in use by other domain" - fi - - success -fi - -exit 0 --------------010701080909030302030307 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel --------------010701080909030302030307--