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authorAnthony Liguori <aliguori@us.ibm.com>2012-05-01 18:44:03 -0500
committerAnthony Liguori <aliguori@us.ibm.com>2012-05-01 18:44:03 -0500
commit75e4e8475bd6ef2e57145f9d08b731f091a6c889 (patch)
tree5e1e3354b08fc83f087f0d90fd3752b69397027e /qga/commands-posix.c
parent65074706b9353bae7307fcfcbbf63a36f6896aa7 (diff)
parentf789aa7baff33e74c549a249aba3ae7a364d7642 (diff)
Merge remote-tracking branch 'mdroth/qga-pull-4-27-12' into staging
* mdroth/qga-pull-4-27-12: qemu-ga: persist tracking of fsfreeze state via filesystem qemu-ga: add a whitelist for fsfreeze-safe commands qemu-ga: improve recovery options for fsfreeze
Diffstat (limited to 'qga/commands-posix.c')
-rw-r--r--qga/commands-posix.c170
1 files changed, 92 insertions, 78 deletions
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 087c3af7ff..d58730ad80 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -316,44 +316,40 @@ static void guest_file_init(void)
#if defined(CONFIG_FSFREEZE)
-static void disable_logging(void)
-{
- ga_disable_logging(ga_state);
-}
-
-static void enable_logging(void)
-{
- ga_enable_logging(ga_state);
-}
-
typedef struct GuestFsfreezeMount {
char *dirname;
char *devtype;
QTAILQ_ENTRY(GuestFsfreezeMount) next;
} GuestFsfreezeMount;
-struct {
- GuestFsfreezeStatus status;
- QTAILQ_HEAD(, GuestFsfreezeMount) mount_list;
-} guest_fsfreeze_state;
+typedef QTAILQ_HEAD(, GuestFsfreezeMount) GuestFsfreezeMountList;
+
+static void guest_fsfreeze_free_mount_list(GuestFsfreezeMountList *mounts)
+{
+ GuestFsfreezeMount *mount, *temp;
+
+ if (!mounts) {
+ return;
+ }
+
+ QTAILQ_FOREACH_SAFE(mount, mounts, next, temp) {
+ QTAILQ_REMOVE(mounts, mount, next);
+ g_free(mount->dirname);
+ g_free(mount->devtype);
+ g_free(mount);
+ }
+}
/*
* Walk the mount table and build a list of local file systems
*/
-static int guest_fsfreeze_build_mount_list(void)
+static int guest_fsfreeze_build_mount_list(GuestFsfreezeMountList *mounts)
{
struct mntent *ment;
- GuestFsfreezeMount *mount, *temp;
+ GuestFsfreezeMount *mount;
char const *mtab = MOUNTED;
FILE *fp;
- QTAILQ_FOREACH_SAFE(mount, &guest_fsfreeze_state.mount_list, next, temp) {
- QTAILQ_REMOVE(&guest_fsfreeze_state.mount_list, mount, next);
- g_free(mount->dirname);
- g_free(mount->devtype);
- g_free(mount);
- }
-
fp = setmntent(mtab, "r");
if (!fp) {
g_warning("fsfreeze: unable to read mtab");
@@ -377,7 +373,7 @@ static int guest_fsfreeze_build_mount_list(void)
mount->dirname = g_strdup(ment->mnt_dir);
mount->devtype = g_strdup(ment->mnt_type);
- QTAILQ_INSERT_TAIL(&guest_fsfreeze_state.mount_list, mount, next);
+ QTAILQ_INSERT_TAIL(mounts, mount, next);
}
endmntent(fp);
@@ -390,7 +386,11 @@ static int guest_fsfreeze_build_mount_list(void)
*/
GuestFsfreezeStatus qmp_guest_fsfreeze_status(Error **err)
{
- return guest_fsfreeze_state.status;
+ if (ga_is_frozen(ga_state)) {
+ return GUEST_FSFREEZE_STATUS_FROZEN;
+ }
+
+ return GUEST_FSFREEZE_STATUS_THAWED;
}
/*
@@ -400,61 +400,61 @@ GuestFsfreezeStatus qmp_guest_fsfreeze_status(Error **err)
int64_t qmp_guest_fsfreeze_freeze(Error **err)
{
int ret = 0, i = 0;
- struct GuestFsfreezeMount *mount, *temp;
+ GuestFsfreezeMountList mounts;
+ struct GuestFsfreezeMount *mount;
int fd;
char err_msg[512];
slog("guest-fsfreeze called");
- if (guest_fsfreeze_state.status == GUEST_FSFREEZE_STATUS_FROZEN) {
- return 0;
- }
-
- ret = guest_fsfreeze_build_mount_list();
+ QTAILQ_INIT(&mounts);
+ ret = guest_fsfreeze_build_mount_list(&mounts);
if (ret < 0) {
return ret;
}
/* cannot risk guest agent blocking itself on a write in this state */
- disable_logging();
+ ga_set_frozen(ga_state);
- QTAILQ_FOREACH_SAFE(mount, &guest_fsfreeze_state.mount_list, next, temp) {
+ QTAILQ_FOREACH(mount, &mounts, next) {
fd = qemu_open(mount->dirname, O_RDONLY);
if (fd == -1) {
- sprintf(err_msg, "failed to open %s, %s", mount->dirname, strerror(errno));
+ sprintf(err_msg, "failed to open %s, %s", mount->dirname,
+ strerror(errno));
error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
goto error;
}
/* we try to cull filesytems we know won't work in advance, but other
* filesytems may not implement fsfreeze for less obvious reasons.
- * these will report EOPNOTSUPP, so we simply ignore them. when
- * thawing, these filesystems will return an EINVAL instead, due to
- * not being in a frozen state. Other filesystem-specific
- * errors may result in EINVAL, however, so the user should check the
- * number * of filesystems returned here against those returned by the
- * thaw operation to determine whether everything completed
- * successfully
+ * these will report EOPNOTSUPP. we simply ignore these when tallying
+ * the number of frozen filesystems.
+ *
+ * any other error means a failure to freeze a filesystem we
+ * expect to be freezable, so return an error in those cases
+ * and return system to thawed state.
*/
ret = ioctl(fd, FIFREEZE);
- if (ret < 0 && errno != EOPNOTSUPP) {
- sprintf(err_msg, "failed to freeze %s, %s", mount->dirname, strerror(errno));
- error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
- close(fd);
- goto error;
+ if (ret == -1) {
+ if (errno != EOPNOTSUPP) {
+ sprintf(err_msg, "failed to freeze %s, %s",
+ mount->dirname, strerror(errno));
+ error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
+ close(fd);
+ goto error;
+ }
+ } else {
+ i++;
}
close(fd);
-
- i++;
}
- guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_FROZEN;
+ guest_fsfreeze_free_mount_list(&mounts);
return i;
error:
- if (i > 0) {
- qmp_guest_fsfreeze_thaw(NULL);
- }
+ guest_fsfreeze_free_mount_list(&mounts);
+ qmp_guest_fsfreeze_thaw(NULL);
return 0;
}
@@ -464,47 +464,61 @@ error:
int64_t qmp_guest_fsfreeze_thaw(Error **err)
{
int ret;
- GuestFsfreezeMount *mount, *temp;
- int fd, i = 0;
- bool has_error = false;
+ GuestFsfreezeMountList mounts;
+ GuestFsfreezeMount *mount;
+ int fd, i = 0, logged;
+
+ QTAILQ_INIT(&mounts);
+ ret = guest_fsfreeze_build_mount_list(&mounts);
+ if (ret) {
+ error_set(err, QERR_QGA_COMMAND_FAILED,
+ "failed to enumerate filesystems");
+ return 0;
+ }
- QTAILQ_FOREACH_SAFE(mount, &guest_fsfreeze_state.mount_list, next, temp) {
+ QTAILQ_FOREACH(mount, &mounts, next) {
+ logged = false;
fd = qemu_open(mount->dirname, O_RDONLY);
if (fd == -1) {
- has_error = true;
- continue;
- }
- ret = ioctl(fd, FITHAW);
- if (ret < 0 && errno != EOPNOTSUPP && errno != EINVAL) {
- has_error = true;
- close(fd);
continue;
}
+ /* we have no way of knowing whether a filesystem was actually unfrozen
+ * as a result of a successful call to FITHAW, only that if an error
+ * was returned the filesystem was *not* unfrozen by that particular
+ * call.
+ *
+ * since multiple preceeding FIFREEZEs require multiple calls to FITHAW
+ * to unfreeze, continuing issuing FITHAW until an error is returned,
+ * in which case either the filesystem is in an unfreezable state, or,
+ * more likely, it was thawed previously (and remains so afterward).
+ *
+ * also, since the most recent successful call is the one that did
+ * the actual unfreeze, we can use this to provide an accurate count
+ * of the number of filesystems unfrozen by guest-fsfreeze-thaw, which
+ * may * be useful for determining whether a filesystem was unfrozen
+ * during the freeze/thaw phase by a process other than qemu-ga.
+ */
+ do {
+ ret = ioctl(fd, FITHAW);
+ if (ret == 0 && !logged) {
+ i++;
+ logged = true;
+ }
+ } while (ret == 0);
close(fd);
- i++;
}
- if (has_error) {
- guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_ERROR;
- } else {
- guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_THAWED;
- }
- enable_logging();
+ ga_unset_frozen(ga_state);
+ guest_fsfreeze_free_mount_list(&mounts);
return i;
}
-static void guest_fsfreeze_init(void)
-{
- guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_THAWED;
- QTAILQ_INIT(&guest_fsfreeze_state.mount_list);
-}
-
static void guest_fsfreeze_cleanup(void)
{
int64_t ret;
Error *err = NULL;
- if (guest_fsfreeze_state.status == GUEST_FSFREEZE_STATUS_FROZEN) {
+ if (ga_is_frozen(ga_state) == GUEST_FSFREEZE_STATUS_FROZEN) {
ret = qmp_guest_fsfreeze_thaw(&err);
if (ret < 0 || err) {
slog("failed to clean up frozen filesystems");
@@ -933,7 +947,7 @@ int64_t qmp_guest_fsfreeze_thaw(Error **err)
void ga_command_state_init(GAState *s, GACommandState *cs)
{
#if defined(CONFIG_FSFREEZE)
- ga_command_state_add(cs, guest_fsfreeze_init, guest_fsfreeze_cleanup);
+ ga_command_state_add(cs, NULL, guest_fsfreeze_cleanup);
#endif
ga_command_state_add(cs, guest_file_init, NULL);
}