On Tue, Sep 5, 2017 at 2:03 PM, Eryu Guan <eguan@xxxxxxxxxx> wrote: > On Wed, Aug 30, 2017 at 05:51:42PM +0300, Amir Goldstein wrote: >> Imported Josef Bacik's code from: >> https://github.com/josefbacik/log-writes.git >> >> Specialized program for replaying a write log that was recorded by >> device mapper log-writes target. The tools is used to perform >> crash consistency tests, allowing to run an arbitrary check tool >> (fsck) at specified checkpoints in the write log. >> >> [Amir:] >> - Add project Makefile and SOURCE files >> - Document the replay-log auxiliary program >> >> Cc: Josef Bacik <jbacik@xxxxxx> >> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> >> --- ... >> +static int zero_range(struct log *log, u64 start, u64 len) >> +{ >> + u64 bufsize = len; >> + ssize_t ret; >> + char *buf = NULL; >> + >> + if (log->max_zero_size < len) { >> + if (log_writes_verbose) >> + printf("discard len %llu larger than max %llu\n", >> + (unsigned long long)len, >> + (unsigned long long)log->max_zero_size); >> + return 0; >> + } >> + >> + while (!buf) { >> + buf = malloc(sizeof(char) * len); > ^^^^ shouldn't this be bufsize? > Yeh, look like is should be... FYI, zero_range() is used to emulate DISCARD that was recorded on a device that supports DISCARD but then replayed on a device that does not support DISCARD The only time I tested this scenario is when I replayed lof to /dev/null. >> +/* >> + * @log: the log we are manipulating. >> + * @entry_num: the entry we want. >> + * >> + * Seek to the given entry in the log, starting at 0 and ending at >> + * log->nr_entries - 1. >> + */ >> +int log_seek_entry(struct log *log, u64 entry_num) >> +{ >> + u64 i = 0; >> + >> + if (entry_num >= log->nr_entries) { >> + fprintf(stderr, "Invalid entry number\n"); >> + return -1; >> + } >> + >> + if (lseek(log->logfd, log->sectorsize, SEEK_SET) == (off_t)-1) { >> + fprintf(stderr, "Error seeking in file: %d\n", errno); >> + return -1; >> + } > > Hmm, we reset the log position to the first log entry by seeking to > log->sectorsize, shouldn't log->cur_entry be reset to 0 too? Though it > doesn't make any difference for now, because log_seek_entry() is only > called at init time, log->cur_entry is 0 anyway. But still, I think it > should be fixed. > True. > BTW, better to add some comments about the seek, it's not so obvious > it's seeking off the log super block on first read :) > ... >> + >> +/* >> + * Basic info about the log for userspace. >> + */ >> +struct log_write_super { >> + __le64 magic; >> + __le64 version; >> + __le64 nr_entries; >> + __le32 sectorsize; >> +}; >> + >> +/* >> + * sector - the sector we wrote. >> + * nr_sectors - the number of sectors we wrote. >> + * flags - flags for this log entry. >> + * data_len - the size of the data in this log entry, this is for private log >> + * entry stuff, the MARK data provided by userspace for example. >> + */ >> +struct log_write_entry { >> + __le64 sector; >> + __le64 nr_sectors; >> + __le64 flags; >> + __le64 data_len; > > This has to match the in-kernel log_write_entry structure, but the > data_len field is not used in this userspace program, better to add > comments to explain that. OK. also should_stop() should strncmp() with data_len instead of strcmp so there is a use for data_len... > >> +}; >> + >> +#define LOG_IGNORE_DISCARD (1 << 0) >> +#define LOG_DISCARD_NOT_SUPP (1 << 1) >> + >> +struct log { >> + int logfd; >> + int replayfd; >> + unsigned long flags; >> + u64 sectorsize; >> + u64 nr_entries; >> + u64 cur_entry; >> + u64 max_zero_size; >> + off_t cur_pos; > > cur_pos is not used, can be removed? I think it is best if I used it in patch ("replay-log: add validations for corrupt log entries") every time I added lseek(log->logfd, 0, SEEK_CUR) for printing offset in debug logs. -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
