On 2018年03月07日 20:17, Nikolay Borisov wrote: > > > On 7.03.2018 14:14, Qu Wenruo wrote: >> >> > > <snip> > >>>> >>>> SHARED flag is determined after extent map merge, so here we can't rely >>>> on em here. >>> >>> Shouldn't extent maps correspond to 1:1 disk-state. I.e. they are just >>> the memory cache of the extent state. So if we merge them, shouldn't we >>> also merge the on-disk extents as well ? >> >> Not 1:1. >> >> In memory one is merged maybe to save memory. >> >> But on-disk file extents has size limit. >> For compressed one it's 128K and 128M for uncompressed one. > > Fair enough, however 4 extents, 16k each should warrant merging on-disk > as well, no ?
dd oflag=dsync That ensures we won't merge on-disk extents. Thanks, Qu > > <snip> > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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