diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/blklogwrites.c | 147 |
1 files changed, 133 insertions, 14 deletions
diff --git a/block/blklogwrites.c b/block/blklogwrites.c index 272e11a..56154e7 100644 --- a/block/blklogwrites.c +++ b/block/blklogwrites.c @@ -24,6 +24,10 @@ #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 @@ -58,6 +62,11 @@ static QemuOptsList runtime_opts = { .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", @@ -72,6 +81,53 @@ static inline uint32_t blk_log_writes_log2(uint32_t value) return 31 - clz32(value); } +static inline bool blk_log_writes_sector_size_valid(uint32_t sector_size) +{ + return sector_size < (1ull << 24) && is_power_of_2(sector_size); +} + +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, &cur_entry, + sizeof(cur_entry)); + 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) { @@ -80,6 +136,7 @@ static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags, Error *local_err = NULL; int ret; uint64_t log_sector_size; + bool log_append; opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort); qemu_opts_absorb_qdict(opts, options, &local_err); @@ -98,20 +155,6 @@ static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } - log_sector_size = qemu_opt_get_size(opts, "log-sector-size", - BDRV_SECTOR_SIZE); - - if (log_sector_size > (1ull << 23) || !is_power_of_2(log_sector_size)) { - ret = -EINVAL; - error_setg(errp, "Invalid log sector size %"PRIu64, log_sector_size); - goto fail; - } - - s->sectorsize = log_sector_size; - s->sectorbits = blk_log_writes_log2(log_sector_size); - s->cur_log_sector = 1; - s->nr_entries = 0; - /* Open the log file */ s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_file, false, &local_err); @@ -121,7 +164,83 @@ static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags, 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, &log_sb, sizeof(log_sb)); + 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); + ret = 0; +fail_log: + if (ret < 0) { + bdrv_unref_child(bs, s->log_file); + s->log_file = NULL; + } fail: if (ret < 0) { bdrv_unref_child(bs, bs->file); |