qemu-e2k/block/blkdebug.c

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/*
* Block protocol for I/O error injection
*
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
* Copyright (C) 2016-2017 Red Hat, Inc.
* Copyright (c) 2010 Kevin Wolf <kwolf@redhat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
2016-03-14 09:01:28 +01:00
#include "qapi/error.h"
#include "qemu/cutils.h"
#include "qemu/config-file.h"
#include "block/block_int.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "sysemu/qtest.h"
typedef struct BDRVBlkdebugState {
int state;
int new_state;
uint64_t align;
uint64_t max_transfer;
uint64_t opt_write_zero;
uint64_t max_write_zero;
uint64_t opt_discard;
uint64_t max_discard;
/* For blkdebug_refresh_filename() */
char *config_file;
QLIST_HEAD(, BlkdebugRule) rules[BLKDBG__MAX];
QSIMPLEQ_HEAD(, BlkdebugRule) active_rules;
QLIST_HEAD(, BlkdebugSuspendedReq) suspended_reqs;
} BDRVBlkdebugState;
typedef struct BlkdebugAIOCB {
BlockAIOCB common;
int ret;
} BlkdebugAIOCB;
typedef struct BlkdebugSuspendedReq {
Coroutine *co;
char *tag;
QLIST_ENTRY(BlkdebugSuspendedReq) next;
} BlkdebugSuspendedReq;
enum {
ACTION_INJECT_ERROR,
ACTION_SET_STATE,
ACTION_SUSPEND,
};
typedef struct BlkdebugRule {
BlkdebugEvent event;
int action;
int state;
union {
struct {
int error;
int immediately;
int once;
int64_t offset;
} inject;
struct {
int new_state;
} set_state;
struct {
char *tag;
} suspend;
} options;
QLIST_ENTRY(BlkdebugRule) next;
QSIMPLEQ_ENTRY(BlkdebugRule) active_next;
} BlkdebugRule;
static QemuOptsList inject_error_opts = {
.name = "inject-error",
.head = QTAILQ_HEAD_INITIALIZER(inject_error_opts.head),
.desc = {
{
.name = "event",
.type = QEMU_OPT_STRING,
},
{
.name = "state",
.type = QEMU_OPT_NUMBER,
},
{
.name = "errno",
.type = QEMU_OPT_NUMBER,
},
{
.name = "sector",
.type = QEMU_OPT_NUMBER,
},
{
.name = "once",
.type = QEMU_OPT_BOOL,
},
{
.name = "immediately",
.type = QEMU_OPT_BOOL,
},
{ /* end of list */ }
},
};
static QemuOptsList set_state_opts = {
.name = "set-state",
.head = QTAILQ_HEAD_INITIALIZER(set_state_opts.head),
.desc = {
{
.name = "event",
.type = QEMU_OPT_STRING,
},
{
.name = "state",
.type = QEMU_OPT_NUMBER,
},
{
.name = "new_state",
.type = QEMU_OPT_NUMBER,
},
{ /* end of list */ }
},
};
static QemuOptsList *config_groups[] = {
&inject_error_opts,
&set_state_opts,
NULL
};
struct add_rule_data {
BDRVBlkdebugState *s;
int action;
};
static int add_rule(void *opaque, QemuOpts *opts, Error **errp)
{
struct add_rule_data *d = opaque;
BDRVBlkdebugState *s = d->s;
const char* event_name;
int event;
struct BlkdebugRule *rule;
int64_t sector;
/* Find the right event for the rule */
event_name = qemu_opt_get(opts, "event");
if (!event_name) {
error_setg(errp, "Missing event name for rule");
return -1;
}
event = qapi_enum_parse(&BlkdebugEvent_lookup, event_name, -1, errp);
if (event < 0) {
return -1;
}
/* Set attributes common for all actions */
rule = g_malloc0(sizeof(*rule));
*rule = (struct BlkdebugRule) {
.event = event,
.action = d->action,
.state = qemu_opt_get_number(opts, "state", 0),
};
/* Parse action-specific options */
switch (d->action) {
case ACTION_INJECT_ERROR:
rule->options.inject.error = qemu_opt_get_number(opts, "errno", EIO);
rule->options.inject.once = qemu_opt_get_bool(opts, "once", 0);
rule->options.inject.immediately =
qemu_opt_get_bool(opts, "immediately", 0);
sector = qemu_opt_get_number(opts, "sector", -1);
rule->options.inject.offset =
sector == -1 ? -1 : sector * BDRV_SECTOR_SIZE;
break;
case ACTION_SET_STATE:
rule->options.set_state.new_state =
qemu_opt_get_number(opts, "new_state", 0);
break;
case ACTION_SUSPEND:
rule->options.suspend.tag =
g_strdup(qemu_opt_get(opts, "tag"));
break;
};
/* Add the rule */
QLIST_INSERT_HEAD(&s->rules[event], rule, next);
return 0;
}
static void remove_rule(BlkdebugRule *rule)
{
switch (rule->action) {
case ACTION_INJECT_ERROR:
case ACTION_SET_STATE:
break;
case ACTION_SUSPEND:
g_free(rule->options.suspend.tag);
break;
}
QLIST_REMOVE(rule, next);
g_free(rule);
}
static int read_config(BDRVBlkdebugState *s, const char *filename,
QDict *options, Error **errp)
{
FILE *f = NULL;
int ret;
struct add_rule_data d;
Error *local_err = NULL;
if (filename) {
f = fopen(filename, "r");
if (f == NULL) {
error_setg_errno(errp, errno, "Could not read blkdebug config file");
return -errno;
}
ret = qemu_config_parse(f, config_groups, filename);
if (ret < 0) {
error_setg(errp, "Could not parse blkdebug config file");
goto fail;
}
}
qemu_config_parse_qdict(options, config_groups, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
d.s = s;
d.action = ACTION_INJECT_ERROR;
qemu_opts_foreach(&inject_error_opts, add_rule, &d, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
d.action = ACTION_SET_STATE;
qemu_opts_foreach(&set_state_opts, add_rule, &d, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
ret = 0;
fail:
qemu_opts_reset(&inject_error_opts);
qemu_opts_reset(&set_state_opts);
if (f) {
fclose(f);
}
return ret;
}
/* Valid blkdebug filenames look like blkdebug:path/to/config:path/to/image */
static void blkdebug_parse_filename(const char *filename, QDict *options,
Error **errp)
{
const char *c;
/* Parse the blkdebug: prefix */
if (!strstart(filename, "blkdebug:", &filename)) {
/* There was no prefix; therefore, all options have to be already
present in the QDict (except for the filename) */
qdict_put_str(options, "x-image", filename);
return;
}
/* Parse config file path */
c = strchr(filename, ':');
if (c == NULL) {
error_setg(errp, "blkdebug requires both config file and image path");
return;
}
if (c != filename) {
QString *config_path;
config_path = qstring_from_substr(filename, 0, c - filename);
qdict_put(options, "config", config_path);
}
/* TODO Allow multi-level nesting and set file.filename here */
filename = c + 1;
qdict_put_str(options, "x-image", filename);
}
static QemuOptsList runtime_opts = {
.name = "blkdebug",
.head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
.desc = {
{
.name = "config",
.type = QEMU_OPT_STRING,
.help = "Path to the configuration file",
},
{
.name = "x-image",
.type = QEMU_OPT_STRING,
.help = "[internal use only, will be removed]",
},
{
.name = "align",
.type = QEMU_OPT_SIZE,
.help = "Required alignment in bytes",
},
{
.name = "max-transfer",
.type = QEMU_OPT_SIZE,
.help = "Maximum transfer size in bytes",
},
{
.name = "opt-write-zero",
.type = QEMU_OPT_SIZE,
.help = "Optimum write zero alignment in bytes",
},
{
.name = "max-write-zero",
.type = QEMU_OPT_SIZE,
.help = "Maximum write zero size in bytes",
},
{
.name = "opt-discard",
.type = QEMU_OPT_SIZE,
.help = "Optimum discard alignment in bytes",
},
{
.name = "max-discard",
.type = QEMU_OPT_SIZE,
.help = "Maximum discard size in bytes",
},
{ /* end of list */ }
},
};
static int blkdebug_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVBlkdebugState *s = bs->opaque;
QemuOpts *opts;
Error *local_err = NULL;
int ret;
uint64_t align;
opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto out;
}
/* Read rules from config file or command line options */
s->config_file = g_strdup(qemu_opt_get(opts, "config"));
ret = read_config(s, s->config_file, options, errp);
if (ret) {
goto out;
}
/* Set initial state */
s->state = 1;
/* Open the image file */
bs->file = bdrv_open_child(qemu_opt_get(opts, "x-image"), options, "image",
bs, &child_file, false, &local_err);
if (local_err) {
ret = -EINVAL;
error_propagate(errp, local_err);
goto out;
}
bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
(BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP) &
bs->file->bs->supported_zero_flags);
ret = -EINVAL;
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
/* Set alignment overrides */
s->align = qemu_opt_get_size(opts, "align", 0);
if (s->align && (s->align >= INT_MAX || !is_power_of_2(s->align))) {
error_setg(errp, "Cannot meet constraints with align %" PRIu64,
s->align);
goto out;
}
align = MAX(s->align, bs->file->bs->bl.request_alignment);
s->max_transfer = qemu_opt_get_size(opts, "max-transfer", 0);
if (s->max_transfer &&
(s->max_transfer >= INT_MAX ||
!QEMU_IS_ALIGNED(s->max_transfer, align))) {
error_setg(errp, "Cannot meet constraints with max-transfer %" PRIu64,
s->max_transfer);
goto out;
}
s->opt_write_zero = qemu_opt_get_size(opts, "opt-write-zero", 0);
if (s->opt_write_zero &&
(s->opt_write_zero >= INT_MAX ||
!QEMU_IS_ALIGNED(s->opt_write_zero, align))) {
error_setg(errp, "Cannot meet constraints with opt-write-zero %" PRIu64,
s->opt_write_zero);
goto out;
}
s->max_write_zero = qemu_opt_get_size(opts, "max-write-zero", 0);
if (s->max_write_zero &&
(s->max_write_zero >= INT_MAX ||
!QEMU_IS_ALIGNED(s->max_write_zero,
MAX(s->opt_write_zero, align)))) {
error_setg(errp, "Cannot meet constraints with max-write-zero %" PRIu64,
s->max_write_zero);
goto out;
}
s->opt_discard = qemu_opt_get_size(opts, "opt-discard", 0);
if (s->opt_discard &&
(s->opt_discard >= INT_MAX ||
!QEMU_IS_ALIGNED(s->opt_discard, align))) {
error_setg(errp, "Cannot meet constraints with opt-discard %" PRIu64,
s->opt_discard);
goto out;
}
s->max_discard = qemu_opt_get_size(opts, "max-discard", 0);
if (s->max_discard &&
(s->max_discard >= INT_MAX ||
!QEMU_IS_ALIGNED(s->max_discard,
MAX(s->opt_discard, align)))) {
error_setg(errp, "Cannot meet constraints with max-discard %" PRIu64,
s->max_discard);
goto out;
}
ret = 0;
out:
if (ret < 0) {
g_free(s->config_file);
}
qemu_opts_del(opts);
return ret;
}
static int rule_check(BlockDriverState *bs, uint64_t offset, uint64_t bytes)
{
BDRVBlkdebugState *s = bs->opaque;
BlkdebugRule *rule = NULL;
int error;
bool immediately;
QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
uint64_t inject_offset = rule->options.inject.offset;
if (inject_offset == -1 ||
(bytes && inject_offset >= offset &&
inject_offset < offset + bytes))
{
break;
}
}
if (!rule || !rule->options.inject.error) {
return 0;
}
immediately = rule->options.inject.immediately;
error = rule->options.inject.error;
if (rule->options.inject.once) {
blkdebug: fix "once" rule Background: The blkdebug scripts are currently engineered so that when a debug event occurs, a prefilter browses a master list of parsed rules for a certain event and adds them to an "active list" of rules to be used for the forthcoming action, provided the events and state numbers match. Then, once the request is received, the last active rule is used to inject an error if certain parameters match. This active list is cleared every time the prefilter injects a new rule for the first time during a debug event. The "once" rule currently causes the error injection, if it is triggered, to only clear the active list. This is insufficient for preventing future injections of the same rule. Remedy: This patch /deletes/ the rule from the list that the prefilter browses, so it is gone for good. In V2, we remove only the rule of interest from the active list instead of allowing the "once" rule to clear the entire list of active rules. Impact: This affects iotests 026. Several ENOSPC tests that used "once" can be seen to have output that shows multiple failure messages. After this patch, the error messages tend to be smaller and less severe, but the injection can still be seen to be working. I have patched the expected output to expect the smaller error messages. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 1423257977-25630-1-git-send-email-jsnow@redhat.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 22:26:17 +01:00
QSIMPLEQ_REMOVE(&s->active_rules, rule, BlkdebugRule, active_next);
remove_rule(rule);
}
if (!immediately) {
aio_co_schedule(qemu_get_current_aio_context(), qemu_coroutine_self());
qemu_coroutine_yield();
}
return -error;
}
static int coroutine_fn
blkdebug_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
{
int err;
/* Sanity check block layer guarantees */
assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment));
assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment));
if (bs->bl.max_transfer) {
assert(bytes <= bs->bl.max_transfer);
}
err = rule_check(bs, offset, bytes);
if (err) {
return err;
}
return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
}
static int coroutine_fn
blkdebug_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
{
int err;
/* Sanity check block layer guarantees */
assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment));
assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment));
if (bs->bl.max_transfer) {
assert(bytes <= bs->bl.max_transfer);
}
err = rule_check(bs, offset, bytes);
if (err) {
return err;
}
return bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
}
static int blkdebug_co_flush(BlockDriverState *bs)
{
int err = rule_check(bs, 0, 0);
if (err) {
return err;
}
return bdrv_co_flush(bs->file->bs);
}
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
static int coroutine_fn blkdebug_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset, int bytes,
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
BdrvRequestFlags flags)
{
uint32_t align = MAX(bs->bl.request_alignment,
bs->bl.pwrite_zeroes_alignment);
int err;
/* Only pass through requests that are larger than requested
* preferred alignment (so that we test the fallback to writes on
* unaligned portions), and check that the block layer never hands
* us anything unaligned that crosses an alignment boundary. */
if (bytes < align) {
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
assert(QEMU_IS_ALIGNED(offset, align) ||
QEMU_IS_ALIGNED(offset + bytes, align) ||
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
DIV_ROUND_UP(offset, align) ==
DIV_ROUND_UP(offset + bytes, align));
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
return -ENOTSUP;
}
assert(QEMU_IS_ALIGNED(offset, align));
assert(QEMU_IS_ALIGNED(bytes, align));
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
if (bs->bl.max_pwrite_zeroes) {
assert(bytes <= bs->bl.max_pwrite_zeroes);
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
}
err = rule_check(bs, offset, bytes);
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
if (err) {
return err;
}
return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
}
static int coroutine_fn blkdebug_co_pdiscard(BlockDriverState *bs,
int64_t offset, int bytes)
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
{
uint32_t align = bs->bl.pdiscard_alignment;
int err;
/* Only pass through requests that are larger than requested
* minimum alignment, and ensure that unaligned requests do not
* cross optimum discard boundaries. */
if (bytes < bs->bl.request_alignment) {
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
assert(QEMU_IS_ALIGNED(offset, align) ||
QEMU_IS_ALIGNED(offset + bytes, align) ||
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
DIV_ROUND_UP(offset, align) ==
DIV_ROUND_UP(offset + bytes, align));
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
return -ENOTSUP;
}
assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment));
assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment));
if (align && bytes >= align) {
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
assert(QEMU_IS_ALIGNED(offset, align));
assert(QEMU_IS_ALIGNED(bytes, align));
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
}
if (bs->bl.max_pdiscard) {
assert(bytes <= bs->bl.max_pdiscard);
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
}
err = rule_check(bs, offset, bytes);
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
if (err) {
return err;
}
return bdrv_co_pdiscard(bs->file, offset, bytes);
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
}
static int coroutine_fn blkdebug_co_block_status(BlockDriverState *bs,
bool want_zero,
int64_t offset,
int64_t bytes,
int64_t *pnum,
int64_t *map,
BlockDriverState **file)
block: Align block status requests Any device that has request_alignment greater than 512 should be unable to report status at a finer granularity; it may also be simpler for such devices to be guaranteed that the block layer has rounded things out to the granularity boundary (the way the block layer already rounds all other I/O out). Besides, getting the code correct for super-sector alignment also benefits us for the fact that our public interface now has byte granularity, even though none of our drivers have byte-level callbacks. Add an assertion in blkdebug that proves that the block layer never requests status of unaligned sections, similar to what it does on other requests (while still keeping the generic helper in place for when future patches add a throttle driver). Note that iotest 177 already covers this (it would fail if you use just the blkdebug.c hunk without the io.c changes). Meanwhile, we can drop assertions in callers that no longer have to pass in sector-aligned addresses. There is a mid-function scope added for 'count' and 'longret', for a couple of reasons: first, an upcoming patch will add an 'if' statement that checks whether a driver has an old- or new-style callback, and can conveniently use the same scope for less indentation churn at that time. Second, since we are trying to get rid of sector-based computations, wrapping things in a scope makes it easier to group and see what will be deleted in a final cleanup patch once all drivers have been converted to the new-style callback. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-10-12 05:47:17 +02:00
{
assert(QEMU_IS_ALIGNED(offset | bytes, bs->bl.request_alignment));
return bdrv_co_block_status_from_file(bs, want_zero, offset, bytes,
pnum, map, file);
block: Align block status requests Any device that has request_alignment greater than 512 should be unable to report status at a finer granularity; it may also be simpler for such devices to be guaranteed that the block layer has rounded things out to the granularity boundary (the way the block layer already rounds all other I/O out). Besides, getting the code correct for super-sector alignment also benefits us for the fact that our public interface now has byte granularity, even though none of our drivers have byte-level callbacks. Add an assertion in blkdebug that proves that the block layer never requests status of unaligned sections, similar to what it does on other requests (while still keeping the generic helper in place for when future patches add a throttle driver). Note that iotest 177 already covers this (it would fail if you use just the blkdebug.c hunk without the io.c changes). Meanwhile, we can drop assertions in callers that no longer have to pass in sector-aligned addresses. There is a mid-function scope added for 'count' and 'longret', for a couple of reasons: first, an upcoming patch will add an 'if' statement that checks whether a driver has an old- or new-style callback, and can conveniently use the same scope for less indentation churn at that time. Second, since we are trying to get rid of sector-based computations, wrapping things in a scope makes it easier to group and see what will be deleted in a final cleanup patch once all drivers have been converted to the new-style callback. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-10-12 05:47:17 +02:00
}
static void blkdebug_close(BlockDriverState *bs)
{
BDRVBlkdebugState *s = bs->opaque;
BlkdebugRule *rule, *next;
int i;
for (i = 0; i < BLKDBG__MAX; i++) {
QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {
remove_rule(rule);
}
}
g_free(s->config_file);
}
static void suspend_request(BlockDriverState *bs, BlkdebugRule *rule)
{
BDRVBlkdebugState *s = bs->opaque;
BlkdebugSuspendedReq r;
r = (BlkdebugSuspendedReq) {
.co = qemu_coroutine_self(),
.tag = g_strdup(rule->options.suspend.tag),
};
remove_rule(rule);
QLIST_INSERT_HEAD(&s->suspended_reqs, &r, next);
if (!qtest_enabled()) {
printf("blkdebug: Suspended request '%s'\n", r.tag);
}
qemu_coroutine_yield();
if (!qtest_enabled()) {
printf("blkdebug: Resuming request '%s'\n", r.tag);
}
QLIST_REMOVE(&r, next);
g_free(r.tag);
}
static bool process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
bool injected)
{
BDRVBlkdebugState *s = bs->opaque;
/* Only process rules for the current state */
if (rule->state && rule->state != s->state) {
return injected;
}
/* Take the action */
switch (rule->action) {
case ACTION_INJECT_ERROR:
if (!injected) {
QSIMPLEQ_INIT(&s->active_rules);
injected = true;
}
QSIMPLEQ_INSERT_HEAD(&s->active_rules, rule, active_next);
break;
case ACTION_SET_STATE:
s->new_state = rule->options.set_state.new_state;
break;
case ACTION_SUSPEND:
suspend_request(bs, rule);
break;
}
return injected;
}
static void blkdebug_debug_event(BlockDriverState *bs, BlkdebugEvent event)
{
BDRVBlkdebugState *s = bs->opaque;
struct BlkdebugRule *rule, *next;
bool injected;
assert((int)event >= 0 && event < BLKDBG__MAX);
injected = false;
s->new_state = s->state;
QLIST_FOREACH_SAFE(rule, &s->rules[event], next, next) {
injected = process_rule(bs, rule, injected);
}
s->state = s->new_state;
}
static int blkdebug_debug_breakpoint(BlockDriverState *bs, const char *event,
const char *tag)
{
BDRVBlkdebugState *s = bs->opaque;
struct BlkdebugRule *rule;
int blkdebug_event;
blkdebug_event = qapi_enum_parse(&BlkdebugEvent_lookup, event, -1, NULL);
if (blkdebug_event < 0) {
return -ENOENT;
}
rule = g_malloc(sizeof(*rule));
*rule = (struct BlkdebugRule) {
.event = blkdebug_event,
.action = ACTION_SUSPEND,
.state = 0,
.options.suspend.tag = g_strdup(tag),
};
QLIST_INSERT_HEAD(&s->rules[blkdebug_event], rule, next);
return 0;
}
static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag)
{
BDRVBlkdebugState *s = bs->opaque;
BlkdebugSuspendedReq *r, *next;
QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, next) {
if (!strcmp(r->tag, tag)) {
qemu_coroutine_enter(r->co);
return 0;
}
}
return -ENOENT;
}
static int blkdebug_debug_remove_breakpoint(BlockDriverState *bs,
const char *tag)
{
BDRVBlkdebugState *s = bs->opaque;
BlkdebugSuspendedReq *r, *r_next;
BlkdebugRule *rule, *next;
int i, ret = -ENOENT;
for (i = 0; i < BLKDBG__MAX; i++) {
QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {
if (rule->action == ACTION_SUSPEND &&
!strcmp(rule->options.suspend.tag, tag)) {
remove_rule(rule);
ret = 0;
}
}
}
QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, r_next) {
if (!strcmp(r->tag, tag)) {
qemu_coroutine_enter(r->co);
ret = 0;
}
}
return ret;
}
static bool blkdebug_debug_is_suspended(BlockDriverState *bs, const char *tag)
{
BDRVBlkdebugState *s = bs->opaque;
BlkdebugSuspendedReq *r;
QLIST_FOREACH(r, &s->suspended_reqs, next) {
if (!strcmp(r->tag, tag)) {
return true;
}
}
return false;
}
static int64_t blkdebug_getlength(BlockDriverState *bs)
{
return bdrv_getlength(bs->file->bs);
}
static void blkdebug_refresh_filename(BlockDriverState *bs)
{
BDRVBlkdebugState *s = bs->opaque;
const QDictEntry *e;
int ret;
if (!bs->file->bs->exact_filename[0]) {
return;
}
for (e = qdict_first(bs->full_open_options); e;
e = qdict_next(bs->full_open_options, e))
{
/* Real child options are under "image", but "x-image" may
* contain a filename */
if (strcmp(qdict_entry_key(e), "config") &&
strcmp(qdict_entry_key(e), "image") &&
strcmp(qdict_entry_key(e), "x-image") &&
strcmp(qdict_entry_key(e), "driver"))
{
return;
}
}
ret = snprintf(bs->exact_filename, sizeof(bs->exact_filename),
"blkdebug:%s:%s",
s->config_file ?: "", bs->file->bs->exact_filename);
if (ret >= sizeof(bs->exact_filename)) {
/* An overflow makes the filename unusable, so do not report any */
bs->exact_filename[0] = 0;
}
}
static void blkdebug_refresh_limits(BlockDriverState *bs, Error **errp)
{
BDRVBlkdebugState *s = bs->opaque;
if (s->align) {
bs->bl.request_alignment = s->align;
}
if (s->max_transfer) {
bs->bl.max_transfer = s->max_transfer;
}
if (s->opt_write_zero) {
bs->bl.pwrite_zeroes_alignment = s->opt_write_zero;
}
if (s->max_write_zero) {
bs->bl.max_pwrite_zeroes = s->max_write_zero;
}
if (s->opt_discard) {
bs->bl.pdiscard_alignment = s->opt_discard;
}
if (s->max_discard) {
bs->bl.max_pdiscard = s->max_discard;
}
}
static int blkdebug_reopen_prepare(BDRVReopenState *reopen_state,
BlockReopenQueue *queue, Error **errp)
{
return 0;
}
static const char *const blkdebug_strong_runtime_opts[] = {
"config",
"inject-error.",
"set-state.",
"align",
"max-transfer",
"opt-write-zero",
"max-write-zero",
"opt-discard",
"max-discard",
NULL
};
static BlockDriver bdrv_blkdebug = {
.format_name = "blkdebug",
.protocol_name = "blkdebug",
.instance_size = sizeof(BDRVBlkdebugState),
.is_filter = true,
.bdrv_parse_filename = blkdebug_parse_filename,
.bdrv_file_open = blkdebug_open,
.bdrv_close = blkdebug_close,
.bdrv_reopen_prepare = blkdebug_reopen_prepare,
.bdrv_child_perm = bdrv_filter_default_perms,
.bdrv_getlength = blkdebug_getlength,
.bdrv_refresh_filename = blkdebug_refresh_filename,
.bdrv_refresh_limits = blkdebug_refresh_limits,
.bdrv_co_preadv = blkdebug_co_preadv,
.bdrv_co_pwritev = blkdebug_co_pwritev,
.bdrv_co_flush_to_disk = blkdebug_co_flush,
blkdebug: Add pass-through write_zero and discard support In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-29 21:14:16 +02:00
.bdrv_co_pwrite_zeroes = blkdebug_co_pwrite_zeroes,
.bdrv_co_pdiscard = blkdebug_co_pdiscard,
.bdrv_co_block_status = blkdebug_co_block_status,
.bdrv_debug_event = blkdebug_debug_event,
.bdrv_debug_breakpoint = blkdebug_debug_breakpoint,
.bdrv_debug_remove_breakpoint
= blkdebug_debug_remove_breakpoint,
.bdrv_debug_resume = blkdebug_debug_resume,
.bdrv_debug_is_suspended = blkdebug_debug_is_suspended,
.strong_runtime_opts = blkdebug_strong_runtime_opts,
};
static void bdrv_blkdebug_init(void)
{
bdrv_register(&bdrv_blkdebug);
}
block_init(bdrv_blkdebug_init);