From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=37705 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Pke0N-0005iI-78 for qemu-devel@nongnu.org; Wed, 02 Feb 2011 09:48:38 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PkYIZ-0007CI-IF for qemu-devel@nongnu.org; Wed, 02 Feb 2011 03:42:48 -0500 Received: from mx1.redhat.com ([209.132.183.28]:25154) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PkYIZ-0007AP-6B for qemu-devel@nongnu.org; Wed, 02 Feb 2011 03:42:47 -0500 From: Jes.Sorensen@redhat.com Date: Wed, 2 Feb 2011 09:42:39 +0100 Message-Id: <1296636160-991-2-git-send-email-Jes.Sorensen@redhat.com> In-Reply-To: <1296636160-991-1-git-send-email-Jes.Sorensen@redhat.com> References: <1296636160-991-1-git-send-email-Jes.Sorensen@redhat.com> Subject: [Qemu-devel] [PATCH 1/2] Add virtagent file system freeze/thaw List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: lcapitulino@redhat.com, mdroth@linux.vnet.ibm.com, stefanha@linux.vnet.ibm.com, agl@us.ibm.com From: Jes Sorensen Implement freeze/thaw support in the guest, allowing the host to request the guest freezes all it's file systems before a live snapshot is performed. - fsfreeze(): Walk the list of mounted local real file systems, and freeze them. - fsthaw(): Walk the list of previously frozen file systems and thaw them. - fsstatus(): Return the current status of freeze/thaw. The host must poll this function, in case fsfreeze() returned with a timeout, to wait for the operation to finish. Signed-off-by: Jes Sorensen --- virtagent-common.h | 8 ++ virtagent-server.c | 190 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 198 insertions(+), 0 deletions(-) diff --git a/virtagent-common.h b/virtagent-common.h index 5d8f5c1..7c6d9ef 100644 --- a/virtagent-common.h +++ b/virtagent-common.h @@ -61,6 +61,14 @@ typedef struct VAContext { const char *channel_path; } VAContext; +enum va_fsfreeze_status { + FREEZE_ERROR = -1, + FREEZE_THAWED = 0, + FREEZE_INPROGRESS = 1, + FREEZE_FROZEN = 2, + FREEZE_THAWINPROGRESS = 3, +}; + enum va_job_status { VA_JOB_STATUS_PENDING = 0, VA_JOB_STATUS_OK, diff --git a/virtagent-server.c b/virtagent-server.c index 7bb35b2..ffbe163 100644 --- a/virtagent-server.c +++ b/virtagent-server.c @@ -14,6 +14,10 @@ #include #include "qemu_socket.h" #include "virtagent-common.h" +#include +#include +#include +#include static VAServerData *va_server_data; static bool va_enable_syslog = false; /* enable syslog'ing of RPCs */ @@ -217,6 +221,186 @@ static xmlrpc_value *va_hello(xmlrpc_env *env, return result; } + +/* + * Walk the mount table and build a list of local file systems + */ + +struct direntry { + char *dirname; + char *devtype; + struct direntry *next; +}; + +static struct direntry *va_mount_list; +static int va_fsfreeze_status; + +static int build_mount_list(void) +{ + struct mntent *mnt; + struct direntry *entry; + struct direntry *next; + char const *mtab = MOUNTED; + FILE *fp; + + fp = setmntent(mtab, "r"); + if (!fp) { + fprintf(stderr, "unable to read mtab\n"); + goto fail; + } + + while ((mnt = getmntent(fp))) { + /* + * An entry which device name doesn't start with a '/' is + * either a dummy file system or a network file system. + * Add special handling for smbfs and cifs as is done by + * coreutils as well. + */ + if ((mnt->mnt_fsname[0] != '/') || + (strcmp(mnt->mnt_type, "smbfs") == 0) || + (strcmp(mnt->mnt_type, "cifs") == 0)) { + continue; + } + + entry = qemu_malloc(sizeof(struct direntry)); + entry->dirname = qemu_strdup(mnt->mnt_dir); + entry->devtype = qemu_strdup(mnt->mnt_type); + entry->next = va_mount_list; + + va_mount_list = entry; + } + + endmntent(fp); + + return 0; + +fail: + while(va_mount_list) { + next = va_mount_list->next; + qemu_free(va_mount_list->dirname); + qemu_free(va_mount_list->devtype); + qemu_free(va_mount_list); + va_mount_list = next; + } + + return -1; +} + +/* + * va_fsfreeze(): Walk list of mounted file systems in the guest, and + * freeze the ones which are real local file systems. + * rpc return values: Number of file systems frozen, -1 on error. + */ +static xmlrpc_value *va_fsfreeze(xmlrpc_env *env, + xmlrpc_value *params, + void *user_data) +{ + xmlrpc_int32 ret = 0, i = 0; + xmlrpc_value *result; + struct direntry *entry; + int fd; + SLOG("va_fsfreeze()"); + + if (va_fsfreeze_status != FREEZE_THAWED) { + ret = 0; + goto out; + } + + ret = build_mount_list(); + if (ret < 0) { + goto out; + } + + va_fsfreeze_status = FREEZE_INPROGRESS; + + entry = va_mount_list; + while(entry) { + fd = qemu_open(entry->dirname, O_RDONLY); + if (fd == -1) { + ret = errno; + goto error; + } + ret = ioctl(fd, FIFREEZE); + close(fd); + if (ret < 0 && ret != EOPNOTSUPP) { + goto error; + } + + entry = entry->next; + i++; + } + + va_fsfreeze_status = FREEZE_FROZEN; + ret = i; +out: + result = xmlrpc_build_value(env, "i", ret); + return result; +error: + if (i > 0) { + va_fsfreeze_status = FREEZE_ERROR; + } + goto out; +} + +/* + * va_fsthaw(): Walk list of frozen file systems in the guest, and + * thaw them. + * rpc return values: Number of file systems thawed on success, -1 on error. + */ +static xmlrpc_value *va_fsthaw(xmlrpc_env *env, + xmlrpc_value *params, + void *user_data) +{ + xmlrpc_int32 ret; + xmlrpc_value *result; + struct direntry *entry; + int fd, i = 0; + SLOG("va_fsthaw()"); + + if (va_fsfreeze_status != FREEZE_FROZEN) { + ret = 0; + goto out; + } + + while((entry = va_mount_list)) { + fd = qemu_open(entry->dirname, O_RDONLY); + if (fd == -1) { + ret = -1; + goto out; + } + ret = ioctl(fd, FITHAW); + close(fd); + if (ret < 0 && ret != EOPNOTSUPP) { + ret = -1; + goto out; + } + + va_mount_list = entry->next; + qemu_free(entry->dirname); + qemu_free(entry->devtype); + qemu_free(entry); + i++; + } + + va_fsfreeze_status = FREEZE_THAWED; + ret = i; +out: + result = xmlrpc_build_value(env, "i", ret); + return result; +} + +/* va_fsstatus(): Return status of freeze/thaw + * rpc return values: fsfreeze_status + */ +static xmlrpc_value *va_fsstatus(xmlrpc_env *env, + xmlrpc_value *params, + void *user_data) +{ + xmlrpc_value *result = xmlrpc_build_value(env, "i", va_fsfreeze_status); + SLOG("va_fsstatus()"); + return result; +} + typedef struct RPCFunction { xmlrpc_value *(*func)(xmlrpc_env *env, xmlrpc_value *param, void *unused); const char *func_name; @@ -237,6 +421,12 @@ static RPCFunction guest_functions[] = { .func_name = "va.ping" }, { .func = va_capabilities, .func_name = "va.capabilities" }, + { .func = va_fsfreeze, + .func_name = "va.fsfreeze" }, + { .func = va_fsthaw, + .func_name = "va.fsthaw" }, + { .func = va_fsstatus, + .func_name = "va.fsstatus" }, { NULL, NULL } }; static RPCFunction host_functions[] = { -- 1.7.3.5