From: Gao Xiang <hsiangkao@linux.alibaba.com> To: "Andreas Grünbacher" <andreas.gruenbacher@gmail.com> Cc: Christoph Hellwig <hch@lst.de>, Andreas Gruenbacher <agruenba@redhat.com>, "Darrick J . Wong" <djwong@kernel.org>, Matthew Wilcox <willy@infradead.org>, Huang Jianan <huangjianan@oppo.com>, linux-erofs@lists.ozlabs.org, Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v7] iomap: make inline data support more flexible Date: Mon, 26 Jul 2021 20:50:59 +0800 [thread overview] Message-ID: <YP6vs180ThT1A2dO@B-P7TQMD6M-0146.local> (raw) In-Reply-To: <CAHpGcMJhuSApy4eg9jKe2pYq4d7bY-Lg-Bmo9tOANghQ2Hxo-A@mail.gmail.com> Hi Andreas, Christoph, On Mon, Jul 26, 2021 at 02:27:12PM +0200, Andreas Grünbacher wrote: > Am Mo., 26. Juli 2021 um 14:17 Uhr schrieb Christoph Hellwig <hch@lst.de>: > > > > > 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. > > > > > + /* inline and tail-packed data must start page aligned in the file */ > > > + if (WARN_ON_ONCE(offset_in_page(iomap->offset))) > > > + return -EIO; > > > + if (WARN_ON_ONCE(size > PAGE_SIZE - offset_in_page(iomap->inline_data))) > > > + return -EIO; > > > > Why can't we use iomap_inline_data_size_valid here? > > We can now. Gao, can you change that? Thank you all taking so much time on this! much appreciated. I'm fine to update that. > > > That is how can size be different from iomap->length? > > Quoting from my previous reply, > > "In the iomap_readpage case (iomap_begin with flags == 0), > iomap->length will be the amount of data up to the end of the inode. For tail-packing cases, iomap->length is just the length of tail-packing inline extent. > In the iomap_file_buffered_write case (iomap_begin with flags == > IOMAP_WRITE), iomap->length will be the size of iomap->inline_data. > (For extending writes, we need to write beyond the current end of > inode.) So iomap->length isn't all that useful for > iomap_read_inline_data." Ok, now it seems I get your point. For the current gfs2 inline cases: iomap_write_begin iomap_write_begin_inline iomap_read_inline_data here, gfs2 passes a buffer instead with "iomap->length", maybe it could be larger than i_size_read(inode) for gfs2. Is that correct? loff_t max_size = gfs2_max_stuffed_size(ip); iomap->length = max_size; If that is what gfs2 currently does, I think it makes sense to temporarily use as this, but IMO, iomap->inline_bufsize is not iomap->length. These are 2 different concepts. > > > Shouldn't the offset_in_page also go into iomap_inline_data_size_valid, > > which should probably be called iomap_inline_data_valid then? > > Hmm, not sure what you mean: iomap_inline_data_size_valid does take > offset_in_page(iomap->inline_data) into account. > > > > if (iomap->type == IOMAP_INLINE) { > > > + int ret = iomap_read_inline_data(inode, page, iomap); > > > + return ret ?: PAGE_SIZE; > > > The ?: expression without the first leg is really confuing. Especially > > if a good old if is much more readable here. > > I'm sure Gao can change this. > > > int ret = iomap_read_inline_data(inode, page, iomap); > > > > if (ret) > > return ret; > > return PAGE_SIZE; I'm fine to update it if no strong opinion. > > > > > + copied = copy_from_iter(iomap_inline_data(iomap, pos), length, iter); > > > > > > > + copied = copy_to_iter(iomap_inline_data(iomap, pos), length, iter); > > > > Pleae avoid the overly long lines. > > I thought people were okay with 80 character long lines? Christoph mentioned before as below: https://lore.kernel.org/linux-fsdevel/YPVe41YqpfGLNsBS@infradead.org/ We also need to take the offset into account for the write side. I guess it would be nice to have a local variable for the inline address to not duplicate that calculation multiple times. Thanks, Gao Xiang > > Thanks, > Andreas
WARNING: multiple messages have this Message-ID (diff)
From: Gao Xiang <hsiangkao@linux.alibaba.com> To: "Andreas Grünbacher" <andreas.gruenbacher@gmail.com> Cc: Andreas Gruenbacher <agruenba@redhat.com>, "Darrick J . Wong" <djwong@kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Matthew Wilcox <willy@infradead.org>, Linux FS-devel Mailing List <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: Mon, 26 Jul 2021 20:50:59 +0800 [thread overview] Message-ID: <YP6vs180ThT1A2dO@B-P7TQMD6M-0146.local> (raw) In-Reply-To: <CAHpGcMJhuSApy4eg9jKe2pYq4d7bY-Lg-Bmo9tOANghQ2Hxo-A@mail.gmail.com> Hi Andreas, Christoph, On Mon, Jul 26, 2021 at 02:27:12PM +0200, Andreas Grünbacher wrote: > Am Mo., 26. Juli 2021 um 14:17 Uhr schrieb Christoph Hellwig <hch@lst.de>: > > > > > 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. > > > > > + /* inline and tail-packed data must start page aligned in the file */ > > > + if (WARN_ON_ONCE(offset_in_page(iomap->offset))) > > > + return -EIO; > > > + if (WARN_ON_ONCE(size > PAGE_SIZE - offset_in_page(iomap->inline_data))) > > > + return -EIO; > > > > Why can't we use iomap_inline_data_size_valid here? > > We can now. Gao, can you change that? Thank you all taking so much time on this! much appreciated. I'm fine to update that. > > > That is how can size be different from iomap->length? > > Quoting from my previous reply, > > "In the iomap_readpage case (iomap_begin with flags == 0), > iomap->length will be the amount of data up to the end of the inode. For tail-packing cases, iomap->length is just the length of tail-packing inline extent. > In the iomap_file_buffered_write case (iomap_begin with flags == > IOMAP_WRITE), iomap->length will be the size of iomap->inline_data. > (For extending writes, we need to write beyond the current end of > inode.) So iomap->length isn't all that useful for > iomap_read_inline_data." Ok, now it seems I get your point. For the current gfs2 inline cases: iomap_write_begin iomap_write_begin_inline iomap_read_inline_data here, gfs2 passes a buffer instead with "iomap->length", maybe it could be larger than i_size_read(inode) for gfs2. Is that correct? loff_t max_size = gfs2_max_stuffed_size(ip); iomap->length = max_size; If that is what gfs2 currently does, I think it makes sense to temporarily use as this, but IMO, iomap->inline_bufsize is not iomap->length. These are 2 different concepts. > > > Shouldn't the offset_in_page also go into iomap_inline_data_size_valid, > > which should probably be called iomap_inline_data_valid then? > > Hmm, not sure what you mean: iomap_inline_data_size_valid does take > offset_in_page(iomap->inline_data) into account. > > > > if (iomap->type == IOMAP_INLINE) { > > > + int ret = iomap_read_inline_data(inode, page, iomap); > > > + return ret ?: PAGE_SIZE; > > > The ?: expression without the first leg is really confuing. Especially > > if a good old if is much more readable here. > > I'm sure Gao can change this. > > > int ret = iomap_read_inline_data(inode, page, iomap); > > > > if (ret) > > return ret; > > return PAGE_SIZE; I'm fine to update it if no strong opinion. > > > > > + copied = copy_from_iter(iomap_inline_data(iomap, pos), length, iter); > > > > > > > + copied = copy_to_iter(iomap_inline_data(iomap, pos), length, iter); > > > > Pleae avoid the overly long lines. > > I thought people were okay with 80 character long lines? Christoph mentioned before as below: https://lore.kernel.org/linux-fsdevel/YPVe41YqpfGLNsBS@infradead.org/ We also need to take the offset into account for the write side. I guess it would be nice to have a local variable for the inline address to not duplicate that calculation multiple times. Thanks, Gao Xiang > > Thanks, > Andreas
next prev parent reply other threads:[~2021-07-26 12:51 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 [this message] 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 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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