From: Gao Xiang <hsiangkao@linux.alibaba.com> To: Matthew Wilcox <willy@infradead.org>, "Darrick J . Wong" <djwong@kernel.org> Cc: dsterba@suse.cz, Christoph Hellwig <hch@lst.de>, Andreas Gruenbacher <agruenba@redhat.com>, Huang Jianan <huangjianan@oppo.com>, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Gruenbacher <andreas.gruenbacher@gmail.com> Subject: Re: [PATCH v7] iomap: make inline data support more flexible Date: Tue, 27 Jul 2021 23:04:36 +0800 [thread overview] Message-ID: <YQAghPSTWdTGYAm5@B-P7TQMD6M-0146.local> (raw) In-Reply-To: <YQALsvt0UWGW+iMw@casper.infradead.org> On Tue, Jul 27, 2021 at 02:35:46PM +0100, Matthew Wilcox wrote: > On Tue, Jul 27, 2021 at 10:20:42AM +0200, David Sterba wrote: > > On Mon, Jul 26, 2021 at 02:17:02PM +0200, Christoph Hellwig wrote: > > > > Subject: iomap: Support tail packing > > > > > > I can't say I like this "tail packing" language here when we have the > > > perfectly fine inline wording. Same for various comments in the actual > > > code. > > > > Yes please, don't call it tail-packing when it's an inline extent, we'll > > use that for btrfs eventually and conflating the two terms has been > > cofusing users. Except reiserfs, no linux filesystem does tail-packing. > > Hmm ... I see what reiserfs does as packing tails of multiple files into > one block. What gfs2 (and ext4) do is inline data. Erofs packs the > tail of a single file into the same block as the inode. If I understand Plus each erofs block can have multiple inodes (thus multi-tail blocks) oo as long as the meta block itself can fit. No matter what it's called, it's a kind of inline data (I think inline means that data mixes with metadata according to [1]). I was called it tail-block inline initially... whatever. Hopefully, Darrick could update the v8 title if some concern here. [1] https://www.kernel.org/doc/Documentation/filesystems/fiemap.txt Thanks, Gao Xiang > what btrfs does correctly, it stores data in the btree. But (like > gfs2/ext4), it's only for the entire-file-is-small case, not for > its-just-ten-bytes-into-the-last-block case. > > So what would you call what erofs is doing if not tail-packing? > Wikipedia calls it https://en.wikipedia.org/wiki/Block_suballocation > which doesn't quite fit. We need a phrase which means "this isn't > just for small files but for small tails of large files".
WARNING: multiple messages have this Message-ID (diff)
From: Gao Xiang <hsiangkao@linux.alibaba.com> To: Matthew Wilcox <willy@infradead.org>, "Darrick J . Wong" <djwong@kernel.org> Cc: Andreas Gruenbacher <agruenba@redhat.com>, linux-kernel@vger.kernel.org, Andreas Gruenbacher <andreas.gruenbacher@gmail.com>, dsterba@suse.cz, linux-fsdevel@vger.kernel.org, linux-erofs@lists.ozlabs.org, Christoph Hellwig <hch@lst.de> Subject: Re: [PATCH v7] iomap: make inline data support more flexible Date: Tue, 27 Jul 2021 23:04:36 +0800 [thread overview] Message-ID: <YQAghPSTWdTGYAm5@B-P7TQMD6M-0146.local> (raw) In-Reply-To: <YQALsvt0UWGW+iMw@casper.infradead.org> On Tue, Jul 27, 2021 at 02:35:46PM +0100, Matthew Wilcox wrote: > On Tue, Jul 27, 2021 at 10:20:42AM +0200, David Sterba wrote: > > On Mon, Jul 26, 2021 at 02:17:02PM +0200, Christoph Hellwig wrote: > > > > Subject: iomap: Support tail packing > > > > > > I can't say I like this "tail packing" language here when we have the > > > perfectly fine inline wording. Same for various comments in the actual > > > code. > > > > Yes please, don't call it tail-packing when it's an inline extent, we'll > > use that for btrfs eventually and conflating the two terms has been > > cofusing users. Except reiserfs, no linux filesystem does tail-packing. > > Hmm ... I see what reiserfs does as packing tails of multiple files into > one block. What gfs2 (and ext4) do is inline data. Erofs packs the > tail of a single file into the same block as the inode. If I understand Plus each erofs block can have multiple inodes (thus multi-tail blocks) oo as long as the meta block itself can fit. No matter what it's called, it's a kind of inline data (I think inline means that data mixes with metadata according to [1]). I was called it tail-block inline initially... whatever. Hopefully, Darrick could update the v8 title if some concern here. [1] https://www.kernel.org/doc/Documentation/filesystems/fiemap.txt Thanks, Gao Xiang > what btrfs does correctly, it stores data in the btree. But (like > gfs2/ext4), it's only for the entire-file-is-small case, not for > its-just-ten-bytes-into-the-last-block case. > > So what would you call what erofs is doing if not tail-packing? > Wikipedia calls it https://en.wikipedia.org/wiki/Block_suballocation > which doesn't quite fit. We need a phrase which means "this isn't > just for small files but for small tails of large files".
next prev parent reply other threads:[~2021-07-27 15:04 UTC|newest] Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-23 17:41 [PATCH v7] iomap: make inline data support more flexible Gao Xiang 2021-07-23 17:41 ` Gao Xiang 2021-07-23 19:40 ` Matthew Wilcox 2021-07-23 19:40 ` Matthew Wilcox 2021-07-24 0:54 ` Gao Xiang 2021-07-24 0:54 ` Gao Xiang 2021-07-25 21:39 ` Andreas Grünbacher 2021-07-25 21:39 ` Andreas Grünbacher 2021-07-25 22:16 ` Andreas Gruenbacher 2021-07-25 22:16 ` Andreas Gruenbacher 2021-07-26 2:36 ` Gao Xiang 2021-07-26 2:36 ` Gao Xiang 2021-07-26 7:22 ` Andreas Gruenbacher 2021-07-26 7:22 ` Andreas Gruenbacher 2021-07-26 7:38 ` Gao Xiang 2021-07-26 7:38 ` Gao Xiang 2021-07-26 21:36 ` Darrick J. Wong 2021-07-26 21:36 ` Darrick J. Wong 2021-07-26 22:20 ` Andreas Grünbacher 2021-07-26 22:20 ` Andreas Grünbacher 2021-07-26 3:06 ` Matthew Wilcox 2021-07-26 3:06 ` Matthew Wilcox 2021-07-26 6:56 ` Andreas Gruenbacher 2021-07-26 6:56 ` Andreas Gruenbacher 2021-07-26 4:00 ` Gao Xiang 2021-07-26 4:00 ` Gao Xiang 2021-07-26 8:08 ` Andreas Grünbacher 2021-07-26 8:08 ` Andreas Grünbacher 2021-07-26 8:17 ` Gao Xiang 2021-07-26 8:17 ` Gao Xiang 2021-07-26 11:06 ` Andreas Gruenbacher 2021-07-26 11:06 ` Andreas Gruenbacher 2021-07-26 12:17 ` Christoph Hellwig 2021-07-26 12:17 ` Christoph Hellwig 2021-07-26 12:27 ` Andreas Grünbacher 2021-07-26 12:27 ` Andreas Grünbacher 2021-07-26 12:50 ` Gao Xiang 2021-07-26 12:50 ` Gao Xiang 2021-07-26 13:10 ` Andreas Gruenbacher 2021-07-26 13:27 ` Christoph Hellwig 2021-07-26 13:27 ` Christoph Hellwig 2021-07-27 8:20 ` David Sterba 2021-07-27 8:20 ` David Sterba 2021-07-27 13:35 ` Matthew Wilcox 2021-07-27 15:04 ` Gao Xiang [this message] 2021-07-27 15:04 ` Gao Xiang 2021-07-27 16:53 ` David Sterba 2021-07-27 16:53 ` David Sterba 2021-07-26 12:32 ` Matthew Wilcox 2021-07-26 12:32 ` Matthew Wilcox 2021-07-26 13:03 ` Andreas Gruenbacher 2021-07-26 13:03 ` Andreas Gruenbacher 2021-07-26 13:12 ` Gao Xiang 2021-07-26 13:12 ` Gao Xiang 2021-07-26 13:30 ` Christoph Hellwig 2021-07-26 8:08 ` Joseph Qi 2021-07-26 8:08 ` Joseph Qi 2021-08-01 10:29 Andreas Gruenbacher 2021-08-01 10:29 ` Andreas Gruenbacher
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