diff options
| -rw-r--r-- | qapi-schema-guest.json | 26 | ||||
| -rw-r--r-- | qga/commands-posix.c | 139 |
2 files changed, 101 insertions, 64 deletions
diff --git a/qapi-schema-guest.json b/qapi-schema-guest.json index cf18876c57..0eedb98765 100644 --- a/qapi-schema-guest.json +++ b/qapi-schema-guest.json @@ -296,14 +296,10 @@ # # @frozen: all non-network guest filesystems frozen # -# @error: failure to thaw 1 or more -# previously frozen filesystems, or failure to open a previously -# cached filesytem (filesystem unmounted/directory changes, etc). -# # Since: 0.15.0 ## { 'enum': 'GuestFsfreezeStatus', - 'data': [ 'thawed', 'frozen', 'error' ] } + 'data': [ 'thawed', 'frozen' ] } ## # @guest-fsfreeze-status: @@ -312,6 +308,10 @@ # # Returns: GuestFsfreezeStatus ("thawed", "frozen", etc., as defined below) # +# Note: This may fail to properly report the current state as a result of +# qemu-ga having been restarted, or other guest processes having issued +# an fs freeze/thaw. +# # Since: 0.15.0 ## { 'command': 'guest-fsfreeze-status', @@ -320,9 +320,10 @@ ## # @guest-fsfreeze-freeze: # -# Sync and freeze all non-network guest filesystems +# Sync and freeze all freezable, local guest filesystems # -# Returns: Number of file systems frozen on success +# Returns: Number of file systems currently frozen. On error, all filesystems +# will be thawed. # # Since: 0.15.0 ## @@ -332,10 +333,15 @@ ## # @guest-fsfreeze-thaw: # -# Unfreeze frozen guest fileystems +# Unfreeze all frozen guest filesystems +# +# Returns: Number of file systems thawed by this call # -# Returns: Number of file systems thawed -# If error, -1 (unknown error) or -errno +# Note: if return value does not match the previous call to +# guest-fsfreeze-freeze, this likely means some freezable +# filesystems were unfrozen before this call, and that the +# filesystem state may have changed before issuing this +# command. # # Since: 0.15.0 ## diff --git a/qga/commands-posix.c b/qga/commands-posix.c index 087c3af7ff..869d6ee831 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -332,28 +332,38 @@ typedef struct GuestFsfreezeMount { QTAILQ_ENTRY(GuestFsfreezeMount) next; } GuestFsfreezeMount; +typedef QTAILQ_HEAD(, GuestFsfreezeMount) GuestFsfreezeMountList; + struct { GuestFsfreezeStatus status; - QTAILQ_HEAD(, GuestFsfreezeMount) mount_list; } guest_fsfreeze_state; +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 +387,7 @@ 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); @@ -400,17 +410,15 @@ 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; } @@ -418,43 +426,46 @@ int64_t qmp_guest_fsfreeze_freeze(Error **err) /* cannot risk guest agent blocking itself on a write in this state */ disable_logging(); - 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; } @@ -464,39 +475,59 @@ 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; - } + guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_THAWED; enable_logging(); + 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) |