[Libguestfs] [PATCH nbdkit INCOMPLETE 5/6] filters: Move rdelay/wdelay from file plugin to new delay filter.

Previously the file plugin supported ‘rdelay’ and ‘wdelay’ parameters for injecting delays (for testing) into read and write requests. This moves the functionality to a new delay filter so that it can be used with any plugin. --- TODO | 3 - configure.ac | 1 + filters/Makefile.am | 1 + filters/delay/Makefile.am | 62 +++++++++++++ filters/delay/delay.c | 167 ++++++++++++++++++++++++++++++++++ filters/delay/nbdkit-delay-filter.pod | 88 ++++++++++++++++++ plugins/file/file.c | 76 +--------------- plugins/file/nbdkit-file-plugin.pod | 14 +-- 8 files changed, 327 insertions(+), 85 deletions(-) diff --git a/TODO b/TODO index 8eda0d7..3ec45fd 100644 --- a/TODO +++ b/TODO @@ -37,9 +37,6 @@ directed to qemu-nbd for these use cases. Suggestions for filters ----------------------- -* adding artificial delays (see wdelay/rdelay options in the file - plugin) - * injecting artificial errors for testing clients * copy-on-write, a popular feature in other servers diff --git a/configure.ac b/configure.ac index 4892dc4..9376a2e 100644 --- a/configure.ac +++ b/configure.ac @@ -513,6 +513,7 @@ AC_CONFIG_FILES([Makefile plugins/vddk/Makefile plugins/xz/Makefile filters/Makefile + filters/delay/Makefile filters/offset/Makefile src/Makefile src/nbdkit.pc diff --git a/filters/Makefile.am b/filters/Makefile.am index 91fbe6c..e4b2942 100644 --- a/filters/Makefile.am +++ b/filters/Makefile.am @@ -31,4 +31,5 @@ # SUCH DAMAGE. SUBDIRS = \ + delay offset diff --git a/filters/delay/Makefile.am b/filters/delay/Makefile.am new file mode 100644 index 0000000..5b20b69 --- /dev/null +++ b/filters/delay/Makefile.am @@ -0,0 +1,62 @@ +# nbdkit +# Copyright (C) 2018 Red Hat Inc. +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# +# * Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# +# * Neither the name of Red Hat nor the names of its contributors may be +# used to endorse or promote products derived from this software without +# specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, +# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR +# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF +# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT +# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +# SUCH DAMAGE. + +EXTRA_DIST = nbdkit-delay-filter.pod + +CLEANFILES = *~ + +filterdir = $(libdir)/nbdkit/filters + +filter_LTLIBRARIES = nbdkit-delay-filter.la + +nbdkit_delay_filter_la_SOURCES = \ + delay.c \ + $(top_srcdir)/include/nbdkit-filter.h + +nbdkit_delay_filter_la_CPPFLAGS = \ + -I$(top_srcdir)/include +nbdkit_delay_filter_la_CFLAGS = \ + $(WARNINGS_CFLAGS) +nbdkit_delay_filter_la_LDFLAGS = \ + -module -avoid-version -shared + +if HAVE_POD2MAN + +man_MANS = nbdkit-delay-filter.1 +CLEANFILES += $(man_MANS) + +nbdkit-delay-filter.1: nbdkit-delay-filter.pod + $(POD2MAN) $(POD2MAN_ARGS) --section=1 --name=`basename $@ .1` $< $@.t && \ + if grep 'POD ERROR' $@.t; then rm $@.t; exit 1; fi && \ + mv $@.t $@ + +endif diff --git a/filters/delay/delay.c b/filters/delay/delay.c new file mode 100644 index 0000000..24033cd --- /dev/null +++ b/filters/delay/delay.c @@ -0,0 +1,167 @@ +/* nbdkit + * Copyright (C) 2018 Red Hat Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * * Neither the name of Red Hat nor the names of its contributors may be + * used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A + * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <config.h> + +#include <stdio.h> +#include <stdlib.h> +#include <stdint.h> +#include <string.h> +#include <time.h> + +#include <nbdkit-filter.h> + +static int rdelayms = 0; /* read delay (milliseconds) */ +static int wdelayms = 0; /* write delay (milliseconds) */ + +static int +parse_delay (const char *value) +{ + size_t len = strlen (value); + int r; + + if (len > 2 && strcmp (&value[len-2], "ms") == 0) { + if (sscanf (value, "%d", &r) == 1) + return r; + else { + nbdkit_error ("cannot parse rdelay/wdelay milliseconds parameter: %s", + value); + return -1; + } + } + else { + if (sscanf (value, "%d", &r) == 1) + return r * 1000; + else { + nbdkit_error ("cannot parse rdelay/wdelay seconds parameter: %s", + value); + return -1; + } + } +} + +static void +delay (int ms) +{ + if (ms > 0) { + const struct timespec ts = { + .tv_sec = ms / 1000, + .tv_nsec = (ms * 1000000) % 1000000000 + }; + nanosleep (&ts, NULL); + } +} + +static void +read_delay (void) +{ + delay (rdelayms); +} + +static void +write_delay (void) +{ + delay (wdelayms); +} + +/* Called for each key=value passed on the command line. */ +static int +delay_config (const char *key, const char *value, + int (*next) (void *data, const char *key, const char *value), + void *data) +{ + if (strcmp (key, "rdelay") == 0) { + rdelayms = parse_delay (value); + if (rdelayms == -1) + return -1; + return 0; + } + else if (strcmp (key, "wdelay") == 0) { + wdelayms = parse_delay (value); + if (wdelayms == -1) + return -1; + return 0; + } + else + return next (data, key, value); +} + +#define delay_config_help \ + "rdelay=<NN>[ms] Read delay in seconds/milliseconds.\n" \ + "wdelay=<NN>[ms] Write delay in seconds/milliseconds." \ + +/* Read data. */ +static int +delay_pread (void *handle, void *buf, uint32_t count, uint64_t offset, + int (*next) (void *data, + void *buf, uint32_t count, uint64_t offset), + void *data) +{ + read_delay (); + return next (data, buf, count, offset); +} + +/* Write data. */ +static int +delay_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, + int (*next) (void *data, + const void *buf, uint32_t count, uint64_t offset), + void *data) +{ + write_delay (); + return next (data, buf, count, offset); +} + +/* Zero data. */ +static int +delay_zero (void *handle, uint32_t count, uint64_t offset, int may_trim, + int (*next) (void *data, + uint32_t count, uint64_t offset, int may_trim), + void *data) +{ + write_delay (); + return next (data, count, offset, may_trim); +} + +static struct nbdkit_filter filter = { + .name = "delay", + .longname = "nbdkit delay filter", + .version = PACKAGE_VERSION, + .config = delay_config, + .config_help = delay_config_help, + .pread = delay_pread, + .pwrite = delay_pwrite, + .zero = delay_zero, +}; + +NBDKIT_REGISTER_FILTER(filter) diff --git a/filters/delay/nbdkit-delay-filter.pod b/filters/delay/nbdkit-delay-filter.pod new file mode 100644 index 0000000..10aba94 --- /dev/null +++ b/filters/delay/nbdkit-delay-filter.pod @@ -0,0 +1,88 @@ +=encoding utf8 + +=head1 NAME + +nbdkit-delay-filter - nbdkit delay filter + +=head1 SYNOPSIS + + nbdkit --filter=delay plugin rdelay=SECS wdelay=SECS [plugin-args...] + + nbdkit --filter=delay plugin rdelay=<NN>ms wdelay=<NN>ms [plugin-args...] + +=head1 DESCRIPTION + +C<nbdkit-delay-filter> is a filter that delays read and write requests +by some seconds or milliseconds. This is used to simulate a slow or +remote server, or to test certain kinds of race conditions in Linux. + +=head1 PARAMETERS + +=over 4 + +=item B<rdelay=SECS> + +=item B<rdelay=E<lt>NNE<gt>ms> + +The optional read delay in seconds or milliseconds. + +=item B<wdelay=SECS> + +=item B<wdelay=E<lt>NNE<gt>ms> + +The optional write delay in seconds or milliseconds. + +=back + +=head1 SEE ALSO + +L<nbdkit(1)>, +L<nbdkit-filter(3)>. + +=head1 AUTHORS + +Richard W.M. Jones + +=head1 COPYRIGHT + +Copyright (C) 2018 Red Hat Inc. + +=head1 LICENSE + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are +met: + +=over 4 + +=item * + +Redistributions of source code must retain the above copyright +notice, this list of conditions and the following disclaimer. + +=item * + +Redistributions in binary form must reproduce the above copyright +notice, this list of conditions and the following disclaimer in the +documentation and/or other materials provided with the distribution. + +=item * + +Neither the name of Red Hat nor the names of its contributors may be +used to endorse or promote products derived from this software without +specific prior written permission. + +=back + +THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND +ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, +THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR +CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF +USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT +OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +SUCH DAMAGE. diff --git a/plugins/file/file.c b/plugins/file/file.c index 4a91251..1fe4191 100644 --- a/plugins/file/file.c +++ b/plugins/file/file.c @@ -40,7 +40,6 @@ #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> -#include <time.h> #include <errno.h> #include <nbdkit-plugin.h> @@ -50,8 +49,6 @@ #endif static char *filename = NULL; -static int rdelayms = 0; /* read delay (milliseconds) */ -static int wdelayms = 0; /* write delay (milliseconds) */ static void file_unload (void) @@ -59,56 +56,6 @@ file_unload (void) free (filename); } -static int -parse_delay (const char *value) -{ - size_t len = strlen (value); - int r; - - if (len > 2 && strcmp (&value[len-2], "ms") == 0) { - if (sscanf (value, "%d", &r) == 1) - return r; - else { - nbdkit_error ("cannot parse rdelay/wdelay milliseconds parameter: %s", - value); - return -1; - } - } - else { - if (sscanf (value, "%d", &r) == 1) - return r * 1000; - else { - nbdkit_error ("cannot parse rdelay/wdelay seconds parameter: %s", - value); - return -1; - } - } -} - -static void -delay (int ms) -{ - if (ms > 0) { - const struct timespec ts = { - .tv_sec = ms / 1000, - .tv_nsec = (ms * 1000000) % 1000000000 - }; - nanosleep (&ts, NULL); - } -} - -static void -read_delay (void) -{ - delay (rdelayms); -} - -static void -write_delay (void) -{ - delay (wdelayms); -} - /* Called for each key=value passed on the command line. This plugin * only accepts file=<filename>, which is required. */ @@ -122,15 +69,10 @@ file_config (const char *key, const char *value) if (!filename) return -1; } - else if (strcmp (key, "rdelay") == 0) { - rdelayms = parse_delay (value); - if (rdelayms == -1) - return -1; - } - else if (strcmp (key, "wdelay") == 0) { - wdelayms = parse_delay (value); - if (wdelayms == -1) - return -1; + else if (strcmp (key, "rdelay") == 0 || + strcmp (key, "wdelay") == 0) { + nbdkit_error ("add --filter=delay on the command line"); + return -1; } else { nbdkit_error ("unknown parameter '%s'", key); @@ -157,9 +99,7 @@ file_config_complete (void) } #define file_config_help \ - "file=<FILENAME> (required) The filename to serve.\n" \ - "rdelay=<NN>[ms] Read delay in seconds/milliseconds.\n" \ - "wdelay=<NN>[ms] Write delay in seconds/milliseconds." \ + "file=<FILENAME> (required) The filename to serve." \ /* The per-connection handle. */ struct handle { @@ -241,8 +181,6 @@ file_pread (void *handle, void *buf, uint32_t count, uint64_t offset) { struct handle *h = handle; - read_delay (); - while (count > 0) { ssize_t r = pread (h->fd, buf, count, offset); if (r == -1) { @@ -267,8 +205,6 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) { struct handle *h = handle; - write_delay (); - while (count > 0) { ssize_t r = pwrite (h->fd, buf, count, offset); if (r == -1) { @@ -292,8 +228,6 @@ file_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) #endif int r = -1; - write_delay (); - #ifdef FALLOC_FL_PUNCH_HOLE if (may_trim) { r = fallocate (h->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, diff --git a/plugins/file/nbdkit-file-plugin.pod b/plugins/file/nbdkit-file-plugin.pod index a2d1e6a..016513a 100644 --- a/plugins/file/nbdkit-file-plugin.pod +++ b/plugins/file/nbdkit-file-plugin.pod @@ -31,21 +31,13 @@ This parameter is required. =item B<rdelay=E<lt>NNE<gt>ms> -Delay reads for C<SECS> seconds or C<NN> milliseconds. -This is used to simulate a slow or remote server, or to -test certain kinds of race conditions in Linux. - -The default is no delay. - =item B<wdelay=SECS> =item B<wdelay=E<lt>NNE<gt>ms> -Delay writes for C<SECS> seconds or C<NN> milliseconds. -This is used to simulate a slow or remote server, or to -test certain kinds of race conditions in Linux. - -The default is no delay. +These plugin parameters have been moved to the +L<nbdkit-delay-filter(1)> filter. Modify the command line to add +I<--filter=delay> in order to use these parameters. =back -- 2.15.1