2020-04-19 2:06 GMT+09:00, Eric Sandeen <sandeen@xxxxxxxxxxx>: > > > On 4/18/20 11:40 AM, Eric Sandeen wrote: >> On 4/18/20 11:04 AM, Eric Sandeen wrote: >>> since access_time has no corresponding 10msIncrement field, my >>> understanding was that it could only have a 2s granularity. >> >> Maybe your concern is whether the other _time fields should also be >> truncated to 2s even though they have the _ms field? I don't think so; >> the >> s_time_gran already limits in-core timestamp resolution to 10ms, which >> will >> be properly translated when the inode is written to disk. >> >> atime has a different granularity though, so s_time_gran doens't help and >> we >> must manually change it to 2s whenever we call something like >> current_time(), which >> only enforces the 10ms granularity. >> >> So for cases like this: >> >> generic_fillattr(inode, stat); >> + exfat_truncate_atime(&stat->atime); >> >> or this: >> >> inode->i_mtime = inode->i_atime = inode->i_ctime = >> EXFAT_I(inode)->i_crtime = current_time(inode); >> + exfat_truncate_atime(&inode->i_atime); >> >> I think it's clearly the right thing to do; anything finer than 2s will be >> thrown >> away when the vfs inode atime is translated to the disk format, so we >> should never >> hold finer granularity in the in-memory vfs inode. >> >> However, in exfat_get_entry_time() maybe all we need to do is set >> ts->tv_nsec to 0; >> that might be clearer. > > so maybe this is better - > > diff --git a/fs/exfat/misc.c b/fs/exfat/misc.c > index c8b33278d474..2c5629b4e7e6 100644 > --- a/fs/exfat/misc.c > +++ b/fs/exfat/misc.c > @@ -89,7 +89,7 @@ void exfat_get_entry_time(struct exfat_sb_info *sbi, > struct timespec64 *ts, > ts->tv_sec += time_ms / 100; > ts->tv_nsec = (time_ms % 100) * 10 * NSEC_PER_MSEC; > } else > - exfat_truncate_atime(ts); > + ts->tv_nsec = 0; > > if (tz & EXFAT_TZ_VALID) > /* Adjust timezone to UTC0. */ > > > because the conversion should already limit tv_sec to a 2s granularity. Right. I will update it and replace it with old one. Thanks! > > -Eric >
