From: Gao Xiang <gaoxiang25@huawei.com> To: Christoph Hellwig <hch@infradead.org> Cc: Gao Xiang <hsiangkao@aol.com>, Jan Kara <jack@suse.cz>, Dave Chinner <david@fromorbit.com>, LKML <linux-kernel@vger.kernel.org>, Miao Xie <miaoxie@huawei.com>, <devel@driverdev.osuosl.org>, Stephen Rothwell <sfr@canb.auug.org.au>, "Darrick J . Wong" <darrick.wong@oracle.com>, "Linus Torvalds" <torvalds@linux-foundation.org>, Amir Goldstein <amir73il@gmail.com>, Alexander Viro <viro@zeniv.linux.org.uk>, Jaegeuk Kim <jaegeuk@kernel.org>, Theodore Ts'o <tytso@mit.edu>, Pavel Machek <pavel@denx.de>, David Sterba <dsterba@suse.cz>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, <linux-fsdevel@vger.kernel.org>, Andrew Morton <akpm@linux-foundation.org>, <linux-erofs@lists.ozlabs.org> Subject: Re: [PATCH v6 01/24] erofs: add on-disk layout Date: Mon, 2 Sep 2019 21:02:45 +0800 Message-ID: <20190902130245.GC17916@architecture4> (raw) In-Reply-To: <20190902124521.GA22153@infradead.org> Hi Christoph, On Mon, Sep 02, 2019 at 05:45:21AM -0700, Christoph Hellwig wrote: > On Sun, Sep 01, 2019 at 03:54:11PM +0800, Gao Xiang wrote: > > It could be better has a name though, because 1) erofs.mkfs uses this > > definition explicitly, and we keep this on-disk definition erofs_fs.h > > file up with erofs-utils. > > > > 2) For kernel use, first we have, > > datamode < EROFS_INODE_LAYOUT_MAX; and > > !erofs_inode_is_data_compressed, so there are only two mode here, > > 1) EROFS_INODE_FLAT_INLINE, > > 2) EROFS_INODE_FLAT_PLAIN > > if its datamode isn't EROFS_INODE_FLAT_INLINE (tail-end block packing), > > it should be EROFS_INODE_FLAT_PLAIN. > > > > The detailed logic in erofs_read_inode and > > erofs_map_blocks_flatmode.... > > Ok. At least the explicit numbering makes this a little more obvious > now. What seems fairly odd is that there are only various places that > check for some inode layouts/formats but nothing that does a switch > over all of them. (Maybe not explicitly for this part....) erofs_map_blocks_flatmode() ... 97 nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE); 98 lastblk = nblocks - is_inode_flat_inline(inode); ^ here ... Believe me EROFS_INODE_FLAT_PLAIN is used widely for EROFS images.... (if EROFS_INODE_FLAT_INLINE tail-end packing is not suitable and no compression....) > > > > why are we adding a legacy field to a brand new file system? > > > > The difference is just EROFS_INODE_FLAT_COMPRESSION_LEGACY doesn't > > have z_erofs_map_header, so it only supports default (4k clustersize) > > fixed-sized output compression rather than per-file setting, nothing > > special at all... > > It still seems odd to add a legacy field to a brand new file system. Since 4.19 EROFS only supports EROFS_INODE_FLAT_COMPRESSION_LEGACY (per-filesystem setting), we'd like to introduce per-file setting and more configration for future requirements.... > > > > structures, as that keeps it clear in everyones mind what needs to > > > stay persistent and what can be chenged easily. > > > > All fields in this file are on-disk representation by design > > (no logic for in-memory presentation). > > Ok, make sense. Maybe add a note to the top of the file comment > that this is the on-disk format. > > One little oddity is that erofs_inode_is_data_compressed is here, while > is_inode_flat_inline is in internal.h. There are arguments for either > place, but I'd suggest to keep the related macros together. (Just my personal thought... erofs_inode_is_data_compressed operates ondisk field like datamode (because we have 2 datamode for compression, need to wrap them to judge if the file is compressed...) so it stays at erofs_fs.h... is_inode_flat_inline operates in-memory struct inode so it in internal.h....) Thanks, Gao Xiang
next prev parent reply index Thread overview: 159+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang 2019-08-02 12:53 ` [PATCH v6 01/24] erofs: add on-disk layout Gao Xiang 2019-08-29 9:59 ` Christoph Hellwig 2019-08-29 10:32 ` Gao Xiang 2019-08-29 10:36 ` Christoph Hellwig 2019-08-29 10:58 ` Gao Xiang 2019-08-29 15:58 ` Joe Perches 2019-08-29 17:26 ` Gao Xiang 2019-08-30 12:07 ` David Sterba 2019-08-30 12:18 ` Gao Xiang 2019-09-02 8:43 ` Pavel Machek 2019-09-02 14:07 ` David Sterba 2019-09-03 11:27 ` Pavel Machek 2019-08-29 15:41 ` Gao Xiang 2019-09-01 7:54 ` Gao Xiang 2019-09-02 12:45 ` Christoph Hellwig 2019-09-02 13:02 ` Gao Xiang [this message] 2019-09-02 8:40 ` Pavel Machek 2019-09-02 10:35 ` Gao Xiang 2019-08-02 12:53 ` [PATCH v6 02/24] erofs: add erofs in-memory stuffs Gao Xiang 2019-08-02 12:53 ` [PATCH v6 03/24] erofs: add super block operations Gao Xiang 2019-08-29 10:15 ` Christoph Hellwig 2019-08-29 10:50 ` Gao Xiang 2019-08-30 16:39 ` Christoph Hellwig 2019-08-30 17:15 ` Gao Xiang 2019-08-31 0:54 ` Gao Xiang 2019-08-31 6:34 ` Amir Goldstein 2019-08-31 6:48 ` Gao Xiang 2019-09-01 8:54 ` Gao Xiang 2019-09-02 12:51 ` Christoph Hellwig 2019-09-02 14:43 ` Gao Xiang 2019-09-02 15:19 ` Christoph Hellwig 2019-09-02 15:24 ` Gao Xiang 2019-08-02 12:53 ` [PATCH v6 04/24] erofs: add raw address_space operations Gao Xiang 2019-08-29 10:17 ` Christoph Hellwig 2019-08-29 11:46 ` Gao Xiang 2019-08-30 16:40 ` Christoph Hellwig 2019-08-30 17:23 ` Gao Xiang 2019-08-02 12:53 ` [PATCH v6 05/24] erofs: add inode operations Gao Xiang 2019-08-29 10:24 ` Christoph Hellwig 2019-08-29 11:59 ` Gao Xiang 2019-08-30 16:42 ` Christoph Hellwig 2019-08-30 18:46 ` Gao Xiang 2019-09-01 9:34 ` Gao Xiang 2019-09-02 12:53 ` Christoph Hellwig 2019-09-02 13:43 ` David Sterba 2019-09-02 13:55 ` Gao Xiang 2019-08-02 12:53 ` [PATCH v6 06/24] erofs: support special inode Gao Xiang 2019-08-29 10:25 ` Christoph Hellwig 2019-09-01 9:39 ` Gao Xiang 2019-08-02 12:53 ` [PATCH v6 07/24] erofs: add directory operations Gao Xiang 2019-08-02 12:53 ` [PATCH v6 08/24] erofs: add namei functions Gao Xiang 2019-08-29 10:28 ` Christoph Hellwig 2019-08-29 11:28 ` Gao Xiang 2019-08-02 12:53 ` [PATCH v6 09/24] erofs: support tracepoint Gao Xiang 2019-08-02 12:53 ` [PATCH v6 10/24] erofs: update Kconfig and Makefile Gao Xiang 2019-08-02 12:53 ` [PATCH v6 11/24] erofs: introduce xattr & posixacl support Gao Xiang 2019-08-02 12:53 ` [PATCH v6 12/24] erofs: introduce tagged pointer Gao Xiang 2019-08-02 12:53 ` [PATCH v6 13/24] erofs: add compression indexes support Gao Xiang 2019-08-02 12:53 ` [PATCH v6 14/24] erofs: introduce superblock registration Gao Xiang 2019-08-02 12:53 ` [PATCH v6 15/24] erofs: introduce erofs shrinker Gao Xiang 2019-08-02 12:53 ` [PATCH v6 16/24] erofs: introduce workstation for decompression Gao Xiang 2019-08-02 12:53 ` [PATCH v6 17/24] erofs: introduce per-CPU buffers implementation Gao Xiang 2019-08-02 12:53 ` [PATCH v6 18/24] erofs: introduce pagevec for decompression subsystem Gao Xiang 2019-08-02 12:53 ` [PATCH v6 19/24] erofs: add erofs_allocpage() Gao Xiang 2019-08-02 12:53 ` [PATCH v6 20/24] erofs: introduce generic decompression backend Gao Xiang 2019-08-02 12:53 ` [PATCH v6 21/24] erofs: introduce LZ4 decompression inplace Gao Xiang 2019-08-02 12:53 ` [PATCH v6 22/24] erofs: introduce the decompression frontend Gao Xiang 2019-08-02 12:53 ` [PATCH v6 23/24] erofs: introduce cached decompression Gao Xiang 2019-08-02 12:53 ` [PATCH v6 24/24] erofs: add document Gao Xiang 2019-09-01 5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang 2019-09-01 5:51 ` [PATCH 01/21] erofs: remove all the byte offset comments Gao Xiang 2019-09-02 12:05 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 02/21] erofs: on-disk format should have explicitly assigned numbers Gao Xiang 2019-09-02 12:05 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 03/21] erofs: some macros are much more readable as a function Gao Xiang 2019-09-02 12:06 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 04/21] erofs: kill __packed for on-disk structures Gao Xiang 2019-09-02 12:06 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 05/21] erofs: update erofs_inode_is_data_compressed helper Gao Xiang 2019-09-02 12:07 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 06/21] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang 2019-09-02 12:09 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 07/21] erofs: use erofs_inode naming Gao Xiang 2019-09-02 12:10 ` Christoph Hellwig 2019-09-02 12:13 ` Gao Xiang 2019-09-02 12:47 ` Christoph Hellwig 2019-09-02 13:33 ` Gao Xiang 2019-09-01 5:51 ` [PATCH 08/21] erofs: update comments in inode.c Gao Xiang 2019-09-01 5:51 ` [PATCH 09/21] erofs: update erofs symlink stuffs Gao Xiang 2019-09-02 12:11 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 10/21] erofs: kill is_inode_layout_compression() Gao Xiang 2019-09-02 12:11 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 11/21] erofs: use dsb instead of layout for ondisk super_block Gao Xiang 2019-09-02 12:12 ` Christoph Hellwig 2019-09-02 12:15 ` Gao Xiang 2019-09-01 5:51 ` [PATCH 12/21] erofs: kill verbose debug info in erofs_fill_super Gao Xiang 2019-09-02 12:14 ` Christoph Hellwig 2019-09-02 12:18 ` Gao Xiang 2019-09-01 5:51 ` [PATCH 13/21] erofs: simplify erofs_grab_bio() since bio_alloc() never fail Gao Xiang 2019-09-02 12:20 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 14/21] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang 2019-09-02 12:21 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 15/21] erofs: kill __submit_bio() Gao Xiang 2019-09-01 5:51 ` [PATCH 16/21] erofs: kill magic underscores Gao Xiang 2019-09-02 12:26 ` Christoph Hellwig 2019-09-02 12:39 ` Gao Xiang 2019-09-02 12:54 ` Christoph Hellwig 2019-09-02 13:38 ` Gao Xiang 2019-09-01 5:51 ` [PATCH 17/21] erofs: use a switch statement when dealing with the file modes Gao Xiang 2019-09-02 12:27 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 18/21] erofs: add "erofs_" prefix for common and short functions Gao Xiang 2019-09-02 12:28 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 19/21] erofs: kill all erofs specific fault injection Gao Xiang 2019-09-02 12:28 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 20/21] erofs: kill use_vmap module parameter Gao Xiang 2019-09-02 12:31 ` Christoph Hellwig 2019-09-02 12:43 ` Gao Xiang 2019-09-01 5:51 ` [PATCH 21/21] erofs: save one level of indentation Gao Xiang 2019-09-02 12:31 ` Christoph Hellwig 2019-09-02 12:46 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Christoph Hellwig 2019-09-02 14:24 ` Gao Xiang 2019-09-02 15:23 ` Christoph Hellwig 2019-09-02 15:50 ` Gao Xiang 2019-09-03 6:58 ` Christoph Hellwig 2019-09-03 8:17 ` Gao Xiang 2019-09-03 15:37 ` Christoph Hellwig 2019-09-03 15:43 ` Gao Xiang 2019-09-04 2:08 ` [PATCH v2 00/25] " Gao Xiang 2019-09-04 2:08 ` [PATCH v2 01/25] erofs: remove all the byte offset comments Gao Xiang 2019-09-04 2:08 ` [PATCH v2 02/25] erofs: on-disk format should have explicitly assigned numbers Gao Xiang 2019-09-04 2:08 ` [PATCH v2 03/25] erofs: some macros are much more readable as a function Gao Xiang 2019-09-04 2:08 ` [PATCH v2 04/25] erofs: kill __packed for on-disk structures Gao Xiang 2019-09-04 2:08 ` [PATCH v2 05/25] erofs: update erofs_inode_is_data_compressed helper Gao Xiang 2019-09-04 2:08 ` [PATCH v2 06/25] erofs: use feature_incompat rather than requirements Gao Xiang 2019-09-04 2:08 ` [PATCH v2 07/25] erofs: better naming for erofs inode related stuffs Gao Xiang 2019-09-04 2:08 ` [PATCH v2 08/25] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang 2019-09-04 2:08 ` [PATCH v2 09/25] erofs: use erofs_inode naming Gao Xiang 2019-09-04 2:08 ` [PATCH v2 10/25] erofs: update erofs_fs.h comments Gao Xiang 2019-09-04 2:08 ` [PATCH v2 11/25] erofs: update comments in inode.c Gao Xiang 2019-09-04 2:08 ` [PATCH v2 12/25] erofs: better erofs symlink stuffs Gao Xiang 2019-09-04 2:09 ` [PATCH v2 13/25] erofs: use dsb instead of layout for ondisk super_block Gao Xiang 2019-09-04 2:09 ` [PATCH v2 14/25] erofs: kill verbose debug info in erofs_fill_super Gao Xiang 2019-09-04 2:09 ` [PATCH v2 15/25] erofs: localize erofs_grab_bio() Gao Xiang 2019-09-04 2:09 ` [PATCH v2 16/25] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang 2019-09-04 2:09 ` [PATCH v2 17/25] erofs: kill __submit_bio() Gao Xiang 2019-09-04 2:09 ` [PATCH v2 18/25] erofs: add "erofs_" prefix for common and short functions Gao Xiang 2019-09-04 2:09 ` [PATCH v2 19/25] erofs: kill all erofs specific fault injection Gao Xiang 2019-09-04 2:09 ` [PATCH v2 20/25] erofs: kill use_vmap module parameter Gao Xiang 2019-09-04 2:09 ` [PATCH v2 21/25] erofs: save one level of indentation Gao Xiang 2019-09-04 2:09 ` [PATCH v2 22/25] erofs: rename errln/infoln/debugln to erofs_{err,info,dbg} Gao Xiang 2019-09-04 2:09 ` [PATCH v2 23/25] erofs: use read_mapping_page instead of sb_bread Gao Xiang 2019-09-04 2:09 ` [PATCH v2 24/25] erofs: always use iget5_locked Gao Xiang 2019-09-04 2:09 ` [PATCH v2 25/25] erofs: use read_cache_page_gfp for erofs_get_meta_page Gao Xiang 2019-09-04 3:27 ` [PATCH v2 00/25] erofs: patchset addressing Christoph's comments Chao Yu 2019-09-05 1:03 ` Gao Xiang 2019-09-05 11:30 ` Christoph Hellwig 2019-09-04 5:16 ` Christoph Hellwig 2019-09-04 6:08 ` Gao Xiang
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