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Mon, 11 Oct 2021 18:57:10 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyoY/Xa4Xw7ivczlmO9ms2t13BWtRuBIDKwNXoKSSChisi8+RUQEKHw9Ho6XNS5pE3+tIDo/g== X-Received: by 2002:aa7:9884:0:b0:44c:4c1f:6e6 with SMTP id r4-20020aa79884000000b0044c4c1f06e6mr29290627pfl.57.1634003830485; Mon, 11 Oct 2021 18:57:10 -0700 (PDT) Received: from t490s ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id b23sm9193853pfi.135.2021.10.11.18.57.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Oct 2021 18:57:09 -0700 (PDT) Date: Tue, 12 Oct 2021 09:57:02 +0800 From: Peter Xu To: Yang Shi Cc: naoya.horiguchi@nec.com, hughd@google.com, kirill.shutemov@linux.intel.com, willy@infradead.org, osalvador@suse.de, akpm@linux-foundation.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [v3 PATCH 4/5] mm: shmem: don't truncate page if memory failure happens Message-ID: References: <20210930215311.240774-1-shy828301@gmail.com> <20210930215311.240774-5-shy828301@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210930215311.240774-5-shy828301@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Sep 30, 2021 at 02:53:10PM -0700, Yang Shi wrote: > diff --git a/mm/shmem.c b/mm/shmem.c > index 88742953532c..75c36b6a405a 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -2456,6 +2456,7 @@ shmem_write_begin(struct file *file, struct address_space *mapping, > struct inode *inode = mapping->host; > struct shmem_inode_info *info = SHMEM_I(inode); > pgoff_t index = pos >> PAGE_SHIFT; > + int ret = 0; > > /* i_rwsem is held by caller */ > if (unlikely(info->seals & (F_SEAL_GROW | > @@ -2466,7 +2467,17 @@ shmem_write_begin(struct file *file, struct address_space *mapping, > return -EPERM; > } > > - return shmem_getpage(inode, index, pagep, SGP_WRITE); > + ret = shmem_getpage(inode, index, pagep, SGP_WRITE); > + > + if (*pagep) { > + if (PageHWPoison(*pagep)) { > + unlock_page(*pagep); > + put_page(*pagep); > + ret = -EIO; > + } > + } > + > + return ret; > } > > static int > @@ -2555,6 +2566,11 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) > unlock_page(page); > } > > + if (page && PageHWPoison(page)) { > + error = -EIO; > + break; > + } > + > /* > * We must evaluate after, since reads (unlike writes) > * are called without i_rwsem protection against truncate [...] > @@ -4193,6 +4216,10 @@ struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, > page = ERR_PTR(error); > else > unlock_page(page); > + > + if (PageHWPoison(page)) > + page = ERR_PTR(-EIO); > + > return page; > #else > /* > diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c > index 7a9008415534..b688d5327177 100644 > --- a/mm/userfaultfd.c > +++ b/mm/userfaultfd.c > @@ -233,6 +233,11 @@ static int mcontinue_atomic_pte(struct mm_struct *dst_mm, > goto out; > } > > + if (PageHWPoison(page)) { > + ret = -EIO; > + goto out_release; > + } > + > ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr, > page, false, wp_copy); > if (ret) > -- > 2.26.2 > These are shmem_getpage_gfp() call sites: shmem_getpage[151] return shmem_getpage_gfp(inode, index, pagep, sgp, shmem_fault[2112] err = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, SGP_CACHE, shmem_read_mapping_page_gfp[4188] error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, These are further shmem_getpage() call sites: collapse_file[1735] if (shmem_getpage(mapping->host, index, &page, shmem_undo_range[965] shmem_getpage(inode, start - 1, &page, SGP_READ); shmem_undo_range[980] shmem_getpage(inode, end, &page, SGP_READ); shmem_write_begin[2467] return shmem_getpage(inode, index, pagep, SGP_WRITE); shmem_file_read_iter[2544] error = shmem_getpage(inode, index, &page, sgp); shmem_fallocate[2733] error = shmem_getpage(inode, index, &page, SGP_FALLOC); shmem_symlink[3079] error = shmem_getpage(inode, 0, &page, SGP_WRITE); shmem_get_link[3120] error = shmem_getpage(inode, 0, &page, SGP_READ); mcontinue_atomic_pte[235] ret = shmem_getpage(inode, pgoff, &page, SGP_READ); Wondering whether this patch covered all of them. This also reminded me that whether we should simply fail shmem_getpage_gfp() directly, then all above callers will get a proper failure, rather than we do PageHWPoison() check everywhere? -- Peter Xu