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Fri, 11 Sep 2020 11:43:43 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5859CAC3F; Fri, 11 Sep 2020 13:55:37 +0000 (UTC) Subject: Re: [PATCH 13/17] btrfs: extent_io: only require sector size alignment for page read To: Qu Wenruo , linux-btrfs@vger.kernel.org References: <20200908075230.86856-1-wqu@suse.com> <20200908075230.86856-14-wqu@suse.com> From: Nikolay Borisov Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= xsFNBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/nSSP8YgfwoOqwrP+JR4pIqRK0AWWeWCSwmZ T7g+RbfPFlmQp+EwFWOtABXlKC54zgSf+uulGwx5JAUFVUIRBmnHOYi/lUiE0yhpnb1KCA7f u/W+DkwGerXqhhe9TvQoGwgCKNfzFPZoM+gZrm+kWv03QLUCr210n4cwaCPJ0Nr9Z3c582xc bCUVbsjt7BN0CFa2BByulrx5xD9sDAYIqfLCcZetAqsTRGxM7LD0kh5WlKzOeAXj5r8DOrU2 GdZS33uKZI/kZJZVytSmZpswDsKhnGzRN1BANGP8sC+WD4eRXajOmNh2HL4P+meO1TlM3GLl EQd2shHFY0qjEo7wxKZI1RyZZ5AgJnSmehrPCyuIyVY210CbMaIKHUIsTqRgY5GaNME24w7h TyyVCy2qAM8fLJ4Vw5bycM/u5xfWm7gyTb9V1TkZ3o1MTrEsrcqFiRrBY94Rs0oQkZvunqia c+NprYSaOG1Cta14o94eMH271Kka/reEwSZkC7T+o9hZ4zi2CcLcY0DXj0qdId7vUKSJjEep c++s8ncFekh1MPhkOgNj8pk17OAESanmDwksmzh1j12lgA5lTFPrJeRNu6/isC2zyZhTwMWs k3LkcTa8ZXxh0RfWAqgx/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABzSJOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuZGU+wsF4BBMBAgAiBQJYijkSAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAAKCRBxvoJG5T8oV/B6D/9a8EcRPdHg8uLEPywuJR8URwXzkofT5bZE IfGF0Z+Lt2ADe+nLOXrwKsamhweUFAvwEUxxnndovRLPOpWerTOAl47lxad08080jXnGfYFS Dc+ew7C3SFI4tFFHln8Y22Q9075saZ2yQS1ywJy+TFPADIprAZXnPbbbNbGtJLoq0LTiESnD w/SUC6sfikYwGRS94Dc9qO4nWyEvBK3Ql8NkoY0Sjky3B0vL572Gq0ytILDDGYuZVo4alUs8 LeXS5ukoZIw1QYXVstDJQnYjFxYgoQ5uGVi4t7FsFM/6ykYDzbIPNOx49Rbh9W4uKsLVhTzG BDTzdvX4ARl9La2kCQIjjWRg+XGuBM5rxT/NaTS78PXjhqWNYlGc5OhO0l8e5DIS2tXwYMDY LuHYNkkpMFksBslldvNttSNei7xr5VwjVqW4vASk2Aak5AleXZS+xIq2FADPS/XSgIaepyTV tkfnyreep1pk09cjfXY4A7qpEFwazCRZg9LLvYVc2M2eFQHDMtXsH59nOMstXx2OtNMcx5p8 0a5FHXE/HoXz3p9bD0uIUq6p04VYOHsMasHqHPbsMAq9V2OCytJQPWwe46bBjYZCOwG0+x58 fBFreP/NiJNeTQPOa6FoxLOLXMuVtpbcXIqKQDoEte9aMpoj9L24f60G4q+pL/54ql2VRscK d87BTQRYigc+ARAAyJSq9EFk28++SLfg791xOh28tLI6Yr8wwEOvM3wKeTfTZd+caVb9gBBy wxYhIopKlK1zq2YP7ZjTP1aPJGoWvcQZ8fVFdK/1nW+Z8/NTjaOx1mfrrtTGtFxVBdSCgqBB jHTnlDYV1R5plJqK+ggEP1a0mr/rpQ9dFGvgf/5jkVpRnH6BY0aYFPprRL8ZCcdv2DeeicOO YMobD5g7g/poQzHLLeT0+y1qiLIFefNABLN06Lf0GBZC5l8hCM3Rpb4ObyQ4B9PmL/KTn2FV Xq/c0scGMdXD2QeWLePC+yLMhf1fZby1vVJ59pXGq+o7XXfYA7xX0JsTUNxVPx/MgK8aLjYW hX+TRA4bCr4uYt/S3ThDRywSX6Hr1lyp4FJBwgyb8iv42it8KvoeOsHqVbuCIGRCXqGGiaeX Wa0M/oxN1vJjMSIEVzBAPi16tztL/wQtFHJtZAdCnuzFAz8ue6GzvsyBj97pzkBVacwp3/Mw qbiu7sDz7yB0d7J2tFBJYNpVt/Lce6nQhrvon0VqiWeMHxgtQ4k92Eja9u80JDaKnHDdjdwq FUikZirB28UiLPQV6PvCckgIiukmz/5ctAfKpyYRGfez+JbAGl6iCvHYt/wAZ7Oqe/3Cirs5 KhaXBcMmJR1qo8QH8eYZ+qhFE3bSPH446+5oEw8A9v5oonKV7zMAEQEAAcLBXwQYAQIACQUC WIoHPgIbDAAKCRBxvoJG5T8oV1pyD/4zdXdOL0lhkSIjJWGqz7Idvo0wjVHSSQCbOwZDWNTN JBTP0BUxHpPu/Z8gRNNP9/k6i63T4eL1xjy4umTwJaej1X15H8Hsh+zakADyWHadbjcUXCkg OJK4NsfqhMuaIYIHbToi9K5pAKnV953xTrK6oYVyd/Rmkmb+wgsbYQJ0Ur1Ficwhp6qU1CaJ mJwFjaWaVgUERoxcejL4ruds66LM9Z1Qqgoer62ZneID6ovmzpCWbi2sfbz98+kW46aA/w8r 7sulgs1KXWhBSv5aWqKU8C4twKjlV2XsztUUsyrjHFj91j31pnHRklBgXHTD/pSRsN0UvM26 lPs0g3ryVlG5wiZ9+JbI3sKMfbdfdOeLxtL25ujs443rw1s/PVghphoeadVAKMPINeRCgoJH zZV/2Z/myWPRWWl/79amy/9MfxffZqO9rfugRBORY0ywPHLDdo9Kmzoxoxp9w3uTrTLZaT9M KIuxEcV8wcVjr+Wr9zRl06waOCkgrQbTPp631hToxo+4rA1jiQF2M80HAet65ytBVR2pFGZF zGYYLqiG+mpUZ+FPjxk9kpkRYz61mTLSY7tuFljExfJWMGfgSg1OxfLV631jV1TcdUnx+h3l Sqs2vMhAVt14zT8mpIuu2VNxcontxgVr1kzYA/tQg32fVRbGr449j1gw57BV9i0vww== Message-ID: <89fd9545-c539-3f58-e48a-218a9b111edd@suse.com> Date: Fri, 11 Sep 2020 16:55:21 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200908075230.86856-14-wqu@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 8.09.20 г. 10:52 ч., Qu Wenruo wrote: > If we're reading partial page, btrfs will warn about this as our > read/write are always done in sector size, which equals page size. > > But for the incoming subpage RO support, our data read is only aligned > to sectorsize, which can be smaller than page size. > > Thus here we change the warning condition to check it against > sectorsize, thus the behavior is not changed for regular sectorsize == > PAGE_SIZE case, while won't report error for subpage read. > > Also, pass the proper start/end with bv_offset for check_data_csum() to > handle. > > Signed-off-by: Qu Wenruo > --- > fs/btrfs/extent_io.c | 19 ++++++++++++------- > 1 file changed, 12 insertions(+), 7 deletions(-) > > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > index 81e43d99feda..a83b63ecc5f8 100644 > --- a/fs/btrfs/extent_io.c > +++ b/fs/btrfs/extent_io.c > @@ -2819,6 +2819,7 @@ static void end_bio_extent_readpage(struct bio *bio) > struct page *page = bvec->bv_page; > struct inode *inode = page->mapping->host; > struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > + u32 sectorsize = fs_info->sectorsize; > bool data_inode = btrfs_ino(BTRFS_I(inode)) > != BTRFS_BTREE_INODE_OBJECTID; > > @@ -2829,13 +2830,17 @@ static void end_bio_extent_readpage(struct bio *bio) > tree = &BTRFS_I(inode)->io_tree; > failure_tree = &BTRFS_I(inode)->io_failure_tree; > > - /* We always issue full-page reads, but if some block > + /* > + * We always issue full-sector reads, but if some block > * in a page fails to read, blk_update_request() will > * advance bv_offset and adjust bv_len to compensate. > - * Print a warning for nonzero offsets, and an error > - * if they don't add up to a full page. */ > - if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) { > - if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE) > + * Print a warning for unaligned offsets, and an error > + * if they don't add up to a full sector. > + */ > + if (!IS_ALIGNED(bvec->bv_offset, sectorsize) || > + !IS_ALIGNED(bvec->bv_offset + bvec->bv_len, sectorsize)) { > + if (!IS_ALIGNED(bvec->bv_offset + bvec->bv_len, > + sectorsize)) Duplicated check ... > btrfs_err(fs_info, > "partial page read in btrfs with offset %u and length %u", > bvec->bv_offset, bvec->bv_len); > @@ -2845,8 +2850,8 @@ static void end_bio_extent_readpage(struct bio *bio) > bvec->bv_offset, bvec->bv_len); > } > > - start = page_offset(page); > - end = start + bvec->bv_offset + bvec->bv_len - 1; > + start = page_offset(page) + bvec->bv_offset; > + end = start + bvec->bv_len - 1; nit: 'start' and 'end' must really be renamed - to file_offset and file_end because they represent values in the logical namespace of the file. And given the context they are used i.e endio handler where we also deal with extent starts and physical offsets such a rename is long over due. Perhaps you can create a separate patch when you are resending the series alternatively I'll make a sweep across those low-level functions to clean that up. > len = bvec->bv_len; > > mirror = io_bio->mirror_num; >