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qemu-e2k/block/blklogwrites.c

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/*
* Write logging blk driver based on blkverify and blkdebug.
*
* Copyright (c) 2017 Tuomas Tynkkynen <tuomas@tuxera.com>
* Copyright (c) 2018 Aapo Vienamo <aapo@tuxera.com>
* Copyright (c) 2018 Ari Sundholm <ari@tuxera.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/sockets.h" /* for EINPROGRESS on Windows */
#include "block/block_int.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "qemu/cutils.h"
#include "qemu/module.h"
#include "qemu/option.h"
/* Disk format stuff - taken from Linux drivers/md/dm-log-writes.c */
#define LOG_FLUSH_FLAG (1 << 0)
#define LOG_FUA_FLAG (1 << 1)
#define LOG_DISCARD_FLAG (1 << 2)
#define LOG_MARK_FLAG (1 << 3)
#define LOG_FLAG_MASK (LOG_FLUSH_FLAG \
| LOG_FUA_FLAG \
| LOG_DISCARD_FLAG \
| LOG_MARK_FLAG)
#define WRITE_LOG_VERSION 1ULL
#define WRITE_LOG_MAGIC 0x6a736677736872ULL
/* All fields are little-endian. */
struct log_write_super {
uint64_t magic;
uint64_t version;
uint64_t nr_entries;
uint32_t sectorsize;
} QEMU_PACKED;
struct log_write_entry {
uint64_t sector;
uint64_t nr_sectors;
uint64_t flags;
uint64_t data_len;
} QEMU_PACKED;
/* End of disk format structures. */
typedef struct {
BdrvChild *log_file;
uint32_t sectorsize;
uint32_t sectorbits;
uint64_t cur_log_sector;
uint64_t nr_entries;
uint64_t update_interval;
} BDRVBlkLogWritesState;
static QemuOptsList runtime_opts = {
.name = "blklogwrites",
.head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
.desc = {
{
.name = "log-append",
.type = QEMU_OPT_BOOL,
.help = "Append to an existing log",
},
{
.name = "log-sector-size",
.type = QEMU_OPT_SIZE,
.help = "Log sector size",
},
{
.name = "log-super-update-interval",
.type = QEMU_OPT_NUMBER,
.help = "Log superblock update interval (# of write requests)",
},
{ /* end of list */ }
},
};
static inline uint32_t blk_log_writes_log2(uint32_t value)
{
assert(value > 0);
return 31 - clz32(value);
}
static inline bool blk_log_writes_sector_size_valid(uint32_t sector_size)
{
return is_power_of_2(sector_size) &&
sector_size >= sizeof(struct log_write_super) &&
sector_size >= sizeof(struct log_write_entry) &&
sector_size < (1ull << 24);
}
static uint64_t blk_log_writes_find_cur_log_sector(BdrvChild *log,
uint32_t sector_size,
uint64_t nr_entries,
Error **errp)
{
uint64_t cur_sector = 1;
uint64_t cur_idx = 0;
uint32_t sector_bits = blk_log_writes_log2(sector_size);
struct log_write_entry cur_entry;
while (cur_idx < nr_entries) {
int read_ret = bdrv_pread(log, cur_sector << sector_bits,
sizeof(cur_entry), &cur_entry, 0);
if (read_ret < 0) {
error_setg_errno(errp, -read_ret,
"Failed to read log entry %"PRIu64, cur_idx);
return (uint64_t)-1ull;
}
if (cur_entry.flags & ~cpu_to_le64(LOG_FLAG_MASK)) {
error_setg(errp, "Invalid flags 0x%"PRIx64" in log entry %"PRIu64,
le64_to_cpu(cur_entry.flags), cur_idx);
return (uint64_t)-1ull;
}
/* Account for the sector of the entry itself */
++cur_sector;
/*
* Account for the data of the write.
* For discards, this data is not present.
*/
if (!(cur_entry.flags & cpu_to_le64(LOG_DISCARD_FLAG))) {
cur_sector += le64_to_cpu(cur_entry.nr_sectors);
}
++cur_idx;
}
return cur_sector;
}
static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVBlkLogWritesState *s = bs->opaque;
QemuOpts *opts;
Error *local_err = NULL;
int ret;
uint64_t log_sector_size;
bool log_append;
opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
if (!qemu_opts_absorb_qdict(opts, options, errp)) {
ret = -EINVAL;
goto fail;
}
/* Open the file */
ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
if (ret < 0) {
goto fail;
}
/* Open the log file */
s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_of_bds,
BDRV_CHILD_METADATA, false, errp);
if (!s->log_file) {
ret = -EINVAL;
goto fail;
}
log_append = qemu_opt_get_bool(opts, "log-append", false);
if (log_append) {
struct log_write_super log_sb = { 0, 0, 0, 0 };
if (qemu_opt_find(opts, "log-sector-size")) {
ret = -EINVAL;
error_setg(errp, "log-append and log-sector-size are mutually "
"exclusive");
goto fail_log;
}
/* Read log superblock or fake one for an empty log */
if (!bdrv_getlength(s->log_file->bs)) {
log_sb.magic = cpu_to_le64(WRITE_LOG_MAGIC);
log_sb.version = cpu_to_le64(WRITE_LOG_VERSION);
log_sb.nr_entries = cpu_to_le64(0);
log_sb.sectorsize = cpu_to_le32(BDRV_SECTOR_SIZE);
} else {
ret = bdrv_pread(s->log_file, 0, sizeof(log_sb), &log_sb, 0);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not read log superblock");
goto fail_log;
}
}
if (log_sb.magic != cpu_to_le64(WRITE_LOG_MAGIC)) {
ret = -EINVAL;
error_setg(errp, "Invalid log superblock magic");
goto fail_log;
}
if (log_sb.version != cpu_to_le64(WRITE_LOG_VERSION)) {
ret = -EINVAL;
error_setg(errp, "Unsupported log version %"PRIu64,
le64_to_cpu(log_sb.version));
goto fail_log;
}
log_sector_size = le32_to_cpu(log_sb.sectorsize);
s->cur_log_sector = 1;
s->nr_entries = 0;
if (blk_log_writes_sector_size_valid(log_sector_size)) {
s->cur_log_sector =
blk_log_writes_find_cur_log_sector(s->log_file, log_sector_size,
le64_to_cpu(log_sb.nr_entries), &local_err);
if (local_err) {
ret = -EINVAL;
error_propagate(errp, local_err);
goto fail_log;
}
s->nr_entries = le64_to_cpu(log_sb.nr_entries);
}
} else {
log_sector_size = qemu_opt_get_size(opts, "log-sector-size",
BDRV_SECTOR_SIZE);
s->cur_log_sector = 1;
s->nr_entries = 0;
}
if (!blk_log_writes_sector_size_valid(log_sector_size)) {
ret = -EINVAL;
error_setg(errp, "Invalid log sector size %"PRIu64, log_sector_size);
goto fail_log;
}
s->sectorsize = log_sector_size;
s->sectorbits = blk_log_writes_log2(log_sector_size);
s->update_interval = qemu_opt_get_number(opts, "log-super-update-interval",
4096);
if (!s->update_interval) {
ret = -EINVAL;
error_setg(errp, "Invalid log superblock update interval %"PRIu64,
s->update_interval);
goto fail_log;
}
ret = 0;
fail_log:
if (ret < 0) {
bdrv_unref_child(bs, s->log_file);
s->log_file = NULL;
}
fail:
qemu_opts_del(opts);
return ret;
}
static void blk_log_writes_close(BlockDriverState *bs)
{
BDRVBlkLogWritesState *s = bs->opaque;
bdrv_unref_child(bs, s->log_file);
s->log_file = NULL;
}
static int64_t blk_log_writes_getlength(BlockDriverState *bs)
{
return bdrv_getlength(bs->file->bs);
}
static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c,
BdrvChildRole role,
BlockReopenQueue *ro_q,
uint64_t perm, uint64_t shrd,
uint64_t *nperm, uint64_t *nshrd)
{
if (!c) {
*nperm = perm & DEFAULT_PERM_PASSTHROUGH;
*nshrd = (shrd & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
return;
}
bdrv_default_perms(bs, c, role, ro_q, perm, shrd,
nperm, nshrd);
}
static void blk_log_writes_refresh_limits(BlockDriverState *bs, Error **errp)
{
BDRVBlkLogWritesState *s = bs->opaque;
bs->bl.request_alignment = s->sectorsize;
}
static int coroutine_fn
blk_log_writes_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
QEMUIOVector *qiov, BdrvRequestFlags flags)
{
return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
}
typedef struct BlkLogWritesFileReq {
BlockDriverState *bs;
uint64_t offset;
uint64_t bytes;
int file_flags;
QEMUIOVector *qiov;
int (*func)(struct BlkLogWritesFileReq *r);
int file_ret;
} BlkLogWritesFileReq;
typedef struct {
BlockDriverState *bs;
QEMUIOVector *qiov;
struct log_write_entry entry;
uint64_t zero_size;
int log_ret;
} BlkLogWritesLogReq;
static void coroutine_fn blk_log_writes_co_do_log(BlkLogWritesLogReq *lr)
{
BDRVBlkLogWritesState *s = lr->bs->opaque;
uint64_t cur_log_offset = s->cur_log_sector << s->sectorbits;
s->nr_entries++;
s->cur_log_sector +=
ROUND_UP(lr->qiov->size, s->sectorsize) >> s->sectorbits;
lr->log_ret = bdrv_co_pwritev(s->log_file, cur_log_offset, lr->qiov->size,
lr->qiov, 0);
/* Logging for the "write zeroes" operation */
if (lr->log_ret == 0 && lr->zero_size) {
cur_log_offset = s->cur_log_sector << s->sectorbits;
s->cur_log_sector +=
ROUND_UP(lr->zero_size, s->sectorsize) >> s->sectorbits;
lr->log_ret = bdrv_co_pwrite_zeroes(s->log_file, cur_log_offset,
lr->zero_size, 0);
}
/* Update super block on flush or every update interval */
if (lr->log_ret == 0 && ((lr->entry.flags & LOG_FLUSH_FLAG)
|| (s->nr_entries % s->update_interval == 0)))
{
struct log_write_super super = {
.magic = cpu_to_le64(WRITE_LOG_MAGIC),
.version = cpu_to_le64(WRITE_LOG_VERSION),
.nr_entries = cpu_to_le64(s->nr_entries),
.sectorsize = cpu_to_le32(s->sectorsize),
};
void *zeroes = g_malloc0(s->sectorsize - sizeof(super));
QEMUIOVector qiov;
qemu_iovec_init(&qiov, 2);
qemu_iovec_add(&qiov, &super, sizeof(super));
qemu_iovec_add(&qiov, zeroes, s->sectorsize - sizeof(super));
lr->log_ret =
bdrv_co_pwritev(s->log_file, 0, s->sectorsize, &qiov, 0);
if (lr->log_ret == 0) {
lr->log_ret = bdrv_co_flush(s->log_file->bs);
}
qemu_iovec_destroy(&qiov);
g_free(zeroes);
}
}
static void coroutine_fn blk_log_writes_co_do_file(BlkLogWritesFileReq *fr)
{
fr->file_ret = fr->func(fr);
}
static int coroutine_fn
blk_log_writes_co_log(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags,
int (*file_func)(BlkLogWritesFileReq *r),
uint64_t entry_flags, bool is_zero_write)
{
QEMUIOVector log_qiov;
size_t niov = qiov ? qiov->niov : 0;
BDRVBlkLogWritesState *s = bs->opaque;
BlkLogWritesFileReq fr = {
.bs = bs,
.offset = offset,
.bytes = bytes,
.file_flags = flags,
.qiov = qiov,
.func = file_func,
};
BlkLogWritesLogReq lr = {
.bs = bs,
.qiov = &log_qiov,
.entry = {
.sector = cpu_to_le64(offset >> s->sectorbits),
.nr_sectors = cpu_to_le64(bytes >> s->sectorbits),
.flags = cpu_to_le64(entry_flags),
.data_len = 0,
},
.zero_size = is_zero_write ? bytes : 0,
};
void *zeroes = g_malloc0(s->sectorsize - sizeof(lr.entry));
assert((1 << s->sectorbits) == s->sectorsize);
assert(bs->bl.request_alignment == s->sectorsize);
assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment));
assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment));
qemu_iovec_init(&log_qiov, niov + 2);
qemu_iovec_add(&log_qiov, &lr.entry, sizeof(lr.entry));
qemu_iovec_add(&log_qiov, zeroes, s->sectorsize - sizeof(lr.entry));
if (qiov) {
qemu_iovec_concat(&log_qiov, qiov, 0, qiov->size);
}
blk_log_writes_co_do_file(&fr);
blk_log_writes_co_do_log(&lr);
qemu_iovec_destroy(&log_qiov);
g_free(zeroes);
if (lr.log_ret < 0) {
return lr.log_ret;
}
return fr.file_ret;
}
static int coroutine_fn
blk_log_writes_co_do_file_pwritev(BlkLogWritesFileReq *fr)
{
return bdrv_co_pwritev(fr->bs->file, fr->offset, fr->bytes,
fr->qiov, fr->file_flags);
}
static int coroutine_fn
blk_log_writes_co_do_file_pwrite_zeroes(BlkLogWritesFileReq *fr)
{
return bdrv_co_pwrite_zeroes(fr->bs->file, fr->offset, fr->bytes,
fr->file_flags);
}
static int coroutine_fn blk_log_writes_co_do_file_flush(BlkLogWritesFileReq *fr)
{
return bdrv_co_flush(fr->bs->file->bs);
}
static int coroutine_fn
blk_log_writes_co_do_file_pdiscard(BlkLogWritesFileReq *fr)
{
return bdrv_co_pdiscard(fr->bs->file, fr->offset, fr->bytes);
}
static int coroutine_fn
blk_log_writes_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
QEMUIOVector *qiov, BdrvRequestFlags flags)
{
return blk_log_writes_co_log(bs, offset, bytes, qiov, flags,
blk_log_writes_co_do_file_pwritev, 0, false);
}
static int coroutine_fn
blk_log_writes_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
int64_t bytes, BdrvRequestFlags flags)
{
return blk_log_writes_co_log(bs, offset, bytes, NULL, flags,
blk_log_writes_co_do_file_pwrite_zeroes, 0,
true);
}
static int coroutine_fn blk_log_writes_co_flush_to_disk(BlockDriverState *bs)
{
return blk_log_writes_co_log(bs, 0, 0, NULL, 0,
blk_log_writes_co_do_file_flush,
LOG_FLUSH_FLAG, false);
}
static int coroutine_fn
blk_log_writes_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes)
{
return blk_log_writes_co_log(bs, offset, bytes, NULL, 0,
blk_log_writes_co_do_file_pdiscard,
LOG_DISCARD_FLAG, false);
}
static const char *const blk_log_writes_strong_runtime_opts[] = {
"log-append",
"log-sector-size",
NULL
};
static BlockDriver bdrv_blk_log_writes = {
.format_name = "blklogwrites",
.instance_size = sizeof(BDRVBlkLogWritesState),
.bdrv_open = blk_log_writes_open,
.bdrv_close = blk_log_writes_close,
.bdrv_getlength = blk_log_writes_getlength,
.bdrv_child_perm = blk_log_writes_child_perm,
.bdrv_refresh_limits = blk_log_writes_refresh_limits,
.bdrv_co_preadv = blk_log_writes_co_preadv,
.bdrv_co_pwritev = blk_log_writes_co_pwritev,
.bdrv_co_pwrite_zeroes = blk_log_writes_co_pwrite_zeroes,
.bdrv_co_flush_to_disk = blk_log_writes_co_flush_to_disk,
.bdrv_co_pdiscard = blk_log_writes_co_pdiscard,
.is_filter = true,
.strong_runtime_opts = blk_log_writes_strong_runtime_opts,
};
static void bdrv_blk_log_writes_init(void)
{
bdrv_register(&bdrv_blk_log_writes);
}
block_init(bdrv_blk_log_writes_init);
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