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