On 2018年03月02日 16:21, Misono, Tomohiro wrote: > On 2018/03/02 14:22, Qu Wenruo wrote: >> Btrfs shows max_inline option into kernel message, but for >> max_inline=4096, btrfs won't really inline 4096 bytes inline data if >> it's not compressed. > > Hello, > I have a question. > > man mount(8) says: > max_inline=bytes > Specify the maximum amount of space, in bytes, that can be > inlined in a metadata B-tree leaf. The value is specified in > bytes, optionally with a K, M, or G suffix, case insensitive. > In practice, this value is limited by the root sector size, > with some space unavailable due to leaf headers. For a 4k > sectorsize, max inline data is ~3900 bytes. > > So, is the size of 4k-(size of leaf header) actually the maximum value > of max_inline instead of 4095 for 4k sectorsize?
Not exactly. For 4K nodesize, max_inline would be 3960 bytes. As leaf header and EXTENT_ITEM header takes extra bytes. For 16K nodesize (default), we can go up to 4095 bytes then. And that man page needs updated, as it should be 4K *nodesize*. Thanks, Qu > > Thanks, > > -- > 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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