From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9653C432BE for ; Wed, 4 Aug 2021 11:21:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FD9C60FC4 for ; Wed, 4 Aug 2021 11:21:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237564AbhHDLV5 (ORCPT ); Wed, 4 Aug 2021 07:21:57 -0400 Received: from out30-42.freemail.mail.aliyun.com ([115.124.30.42]:47707 "EHLO out30-42.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237482AbhHDLVy (ORCPT ); Wed, 4 Aug 2021 07:21:54 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R821e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=alimailimapcm10staff010182156082;MF=hsiangkao@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0Uhy2AfZ_1628076098; Received: from B-P7TQMD6M-0146.local(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0Uhy2AfZ_1628076098) by smtp.aliyun-inc.com(127.0.0.1); Wed, 04 Aug 2021 19:21:39 +0800 Date: Wed, 4 Aug 2021 19:21:38 +0800 From: Gao Xiang To: Chao Yu Cc: linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev, LKML , "Darrick J. Wong" , Liu Bo , Joseph Qi , Liu Jiang , Huang Jianan , Tao Ma Subject: Re: [PATCH v2 2/3] erofs: dax support for non-tailpacking regular file Message-ID: Mail-Followup-To: Chao Yu , linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev, LKML , "Darrick J. Wong" , Liu Bo , Joseph Qi , Liu Jiang , Huang Jianan , Tao Ma References: <20210730194625.93856-1-hsiangkao@linux.alibaba.com> <20210730194625.93856-3-hsiangkao@linux.alibaba.com> <4de79cbb-6977-1172-4e69-5e9040caadf2@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <4de79cbb-6977-1172-4e69-5e9040caadf2@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 04, 2021 at 03:14:34PM +0800, Chao Yu wrote: > On 2021/7/31 3:46, Gao Xiang wrote: > > DAX is quite useful for some VM use cases in order to save guest > > memory extremely with minimal lightweight EROFS. > > > > In order to prepare for such use cases, add preliminary dax support > > for non-tailpacking regular files for now. > > > > Tested with the DRAM-emulated PMEM and the EROFS image generated by > > "mkfs.erofs -Enoinline_data enwik9.fsdax.img enwik9" > > > > Cc: nvdimm@lists.linux.dev > > Cc: linux-fsdevel@vger.kernel.org > > Signed-off-by: Gao Xiang > > --- > > fs/erofs/data.c | 42 +++++++++++++++++++++++++++++-- > > fs/erofs/inode.c | 4 +++ > > fs/erofs/internal.h | 3 +++ > > fs/erofs/super.c | 60 +++++++++++++++++++++++++++++++++++++++++++-- > > 4 files changed, 105 insertions(+), 4 deletions(-) > > > > diff --git a/fs/erofs/data.c b/fs/erofs/data.c > > index 1f97151a9f90..911521293b20 100644 > > --- a/fs/erofs/data.c > > +++ b/fs/erofs/data.c > > @@ -6,7 +6,7 @@ > > #include "internal.h" > > #include > > #include > > - > > +#include > > #include > > static void erofs_readendio(struct bio *bio) > > @@ -323,6 +323,7 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > > return ret; > > iomap->bdev = inode->i_sb->s_bdev; > > + iomap->dax_dev = EROFS_I_SB(inode)->dax_dev; > > iomap->offset = map.m_la; > > iomap->length = map.m_llen; > > iomap->flags = 0; > > @@ -382,6 +383,10 @@ static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) > > if (!iov_iter_count(to)) > > return 0; > > +#ifdef CONFIG_FS_DAX > > + if (IS_DAX(iocb->ki_filp->f_mapping->host)) > > + return dax_iomap_rw(iocb, to, &erofs_iomap_ops); > > +#endif > > if (iocb->ki_flags & IOCB_DIRECT) { > > int err = erofs_prepare_dio(iocb, to); > > @@ -410,9 +415,42 @@ const struct address_space_operations erofs_raw_access_aops = { > > .direct_IO = noop_direct_IO, > > }; > > +#ifdef CONFIG_FS_DAX > > +static vm_fault_t erofs_dax_huge_fault(struct vm_fault *vmf, > > + enum page_entry_size pe_size) > > +{ > > + return dax_iomap_fault(vmf, pe_size, NULL, NULL, &erofs_iomap_ops); > > +} > > + > > +static vm_fault_t erofs_dax_fault(struct vm_fault *vmf) > > +{ > > + return erofs_dax_huge_fault(vmf, PE_SIZE_PTE); > > +} > > + > > +static const struct vm_operations_struct erofs_dax_vm_ops = { > > + .fault = erofs_dax_fault, > > + .huge_fault = erofs_dax_huge_fault, > > +}; > > + > > +static int erofs_file_mmap(struct file *file, struct vm_area_struct *vma) > > +{ > > + if (!IS_DAX(file_inode(file))) > > + return generic_file_readonly_mmap(file, vma); > > + > > + if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) > > + return -EINVAL; > > + > > + vma->vm_ops = &erofs_dax_vm_ops; > > + vma->vm_flags |= VM_HUGEPAGE; > > + return 0; > > +} > > +#else > > +#define erofs_file_mmap generic_file_readonly_mmap > > +#endif > > + > > const struct file_operations erofs_file_fops = { > > .llseek = generic_file_llseek, > > .read_iter = erofs_file_read_iter, > > - .mmap = generic_file_readonly_mmap, > > + .mmap = erofs_file_mmap, > > .splice_read = generic_file_splice_read, > > }; > > diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c > > index 00edb7562fea..e875fba18159 100644 > > --- a/fs/erofs/inode.c > > +++ b/fs/erofs/inode.c > > @@ -174,6 +174,10 @@ static struct page *erofs_read_inode(struct inode *inode, > > inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec; > > inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec; > > + inode->i_flags &= ~S_DAX; > > + if (test_opt(&sbi->ctx, DAX_ALWAYS) && S_ISREG(inode->i_mode) && > > + vi->datalayout == EROFS_INODE_FLAT_PLAIN) > > + inode->i_flags |= S_DAX; > > if (!nblks) > > /* measure inode.i_blocks as generic filesystems */ > > inode->i_blocks = roundup(inode->i_size, EROFS_BLKSIZ) >> 9; > > diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h > > index 2669c785d548..7c9abfc93109 100644 > > --- a/fs/erofs/internal.h > > +++ b/fs/erofs/internal.h > > @@ -83,6 +83,7 @@ struct erofs_sb_info { > > struct erofs_sb_lz4_info lz4; > > #endif /* CONFIG_EROFS_FS_ZIP */ > > + struct dax_device *dax_dev; > > u32 blocks; > > u32 meta_blkaddr; > > #ifdef CONFIG_EROFS_FS_XATTR > > @@ -115,6 +116,8 @@ struct erofs_sb_info { > > /* Mount flags set via mount options or defaults */ > > #define EROFS_MOUNT_XATTR_USER 0x00000010 > > #define EROFS_MOUNT_POSIX_ACL 0x00000020 > > +#define EROFS_MOUNT_DAX_ALWAYS 0x00000040 > > +#define EROFS_MOUNT_DAX_NEVER 0x00000080 > > #define clear_opt(ctx, option) ((ctx)->mount_opt &= ~EROFS_MOUNT_##option) > > #define set_opt(ctx, option) ((ctx)->mount_opt |= EROFS_MOUNT_##option) > > diff --git a/fs/erofs/super.c b/fs/erofs/super.c > > index 8fc6c04b54f4..d5b110fd365d 100644 > > --- a/fs/erofs/super.c > > +++ b/fs/erofs/super.c > > @@ -11,6 +11,7 @@ > > #include > > #include > > #include > > +#include > > #include "xattr.h" > > #define CREATE_TRACE_POINTS > > @@ -355,6 +356,8 @@ enum { > > Opt_user_xattr, > > Opt_acl, > > Opt_cache_strategy, > > + Opt_dax, > > + Opt_dax_enum, > > We need to update doc for those new dax mount options. Yeah, I agree, let me update this soon. > > > Opt_err > > }; > > @@ -365,14 +368,47 @@ static const struct constant_table erofs_param_cache_strategy[] = { > > {} > > }; > > +static const struct constant_table erofs_dax_param_enums[] = { > > + {"always", EROFS_MOUNT_DAX_ALWAYS}, > > + {"never", EROFS_MOUNT_DAX_NEVER}, > > + {} > > +}; > > + > > static const struct fs_parameter_spec erofs_fs_parameters[] = { > > fsparam_flag_no("user_xattr", Opt_user_xattr), > > fsparam_flag_no("acl", Opt_acl), > > fsparam_enum("cache_strategy", Opt_cache_strategy, > > erofs_param_cache_strategy), > > + fsparam_flag("dax", Opt_dax), > > + fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums), > > {} > > }; > > +static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode) > > +{ > > +#ifdef CONFIG_FS_DAX > > + struct erofs_fs_context *ctx = fc->fs_private; > > + > > + switch (mode) { > > + case EROFS_MOUNT_DAX_ALWAYS: > > + warnfc(fc, "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); > > + set_opt(ctx, DAX_ALWAYS); > > + clear_opt(ctx, DAX_NEVER); > > + return true; > > + case EROFS_MOUNT_DAX_NEVER: > > + set_opt(ctx, DAX_NEVER); > > + clear_opt(ctx, DAX_ALWAYS); > > + return true; > > + default: > > + DBG_BUGON(1); > > + return false; > > + } > > +#else > > + errorfc(fc, "dax options not supported"); > > + return false; > > +#endif > > +} > > + > > static int erofs_fc_parse_param(struct fs_context *fc, > > struct fs_parameter *param) > > { > > @@ -412,6 +448,14 @@ static int erofs_fc_parse_param(struct fs_context *fc, > > errorfc(fc, "compression not supported, cache_strategy ignored"); > > #endif > > break; > > + case Opt_dax: > > + if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS)) > > + return -EINVAL; > > + break; > > + case Opt_dax_enum: > > + if (!erofs_fc_set_dax_mode(fc, result.uint_32)) > > + return -EINVAL; > > + break; > > default: > > return -ENOPARAM; > > } > > @@ -496,10 +540,16 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) > > return -ENOMEM; > > sb->s_fs_info = sbi; > > + sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev); > > err = erofs_read_superblock(sb); > > if (err) > > return err; > > + if (test_opt(ctx, DAX_ALWAYS) && > > + !bdev_dax_supported(sb->s_bdev, EROFS_BLKSIZ)) { > > + errorfc(fc, "DAX unsupported by block device. Turning off DAX."); > > + clear_opt(ctx, DAX_ALWAYS); > > + } > > sb->s_flags |= SB_RDONLY | SB_NOATIME; > > sb->s_maxbytes = MAX_LFS_FILESIZE; > > sb->s_time_gran = 1; > > @@ -609,6 +659,8 @@ static void erofs_kill_sb(struct super_block *sb) > > sbi = EROFS_SB(sb); > > if (!sbi) > > return; > > + if (sbi->dax_dev) > > + fs_put_dax(sbi->dax_dev); > > fs_put_dax(sbi->dax_dev); Will update. Thanks, Gao Xiang > > Thanks, > > > kfree(sbi); > > sb->s_fs_info = NULL; > > } > > @@ -711,8 +763,8 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf) > > static int erofs_show_options(struct seq_file *seq, struct dentry *root) > > { > > - struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb); > > - struct erofs_fs_context *ctx __maybe_unused = &sbi->ctx; > > + struct erofs_sb_info *sbi = EROFS_SB(root->d_sb); > > + struct erofs_fs_context *ctx = &sbi->ctx; > > #ifdef CONFIG_EROFS_FS_XATTR > > if (test_opt(ctx, XATTR_USER)) > > @@ -734,6 +786,10 @@ static int erofs_show_options(struct seq_file *seq, struct dentry *root) > > else if (ctx->cache_strategy == EROFS_ZIP_CACHE_READAROUND) > > seq_puts(seq, ",cache_strategy=readaround"); > > #endif > > + if (test_opt(ctx, DAX_ALWAYS)) > > + seq_puts(seq, ",dax=always"); > > + if (test_opt(ctx, DAX_NEVER)) > > + seq_puts(seq, ",dax=never"); > > return 0; > > } > >