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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=ham 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 EDAE9C10F14 for ; Tue, 23 Apr 2019 11:00:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AE41321738 for ; Tue, 23 Apr 2019 11:00:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RJHnBZyp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727366AbfDWLAG (ORCPT ); Tue, 23 Apr 2019 07:00:06 -0400 Received: from mail-yb1-f194.google.com ([209.85.219.194]:43669 "EHLO mail-yb1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726659AbfDWLAG (ORCPT ); Tue, 23 Apr 2019 07:00:06 -0400 Received: by mail-yb1-f194.google.com with SMTP id n19so5554751ybf.10; Tue, 23 Apr 2019 04:00:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=7IXzt0nzIOAJKG+GOlOHwpocfgEQHcHB3c85Qh1MbXQ=; b=RJHnBZypYOqlrWTVmo6yZvbkE4IavwQgpycaL+nLQE0HLaldQhqnevwCQX9ufNLKAM Hv0YONd/e9g6CbKKOKvvtTYAPvPWLX1oD1drbftTA/8YemB4swMbkK3y32z8rSdV8vnf VM9MW6BXOu+xXjgrC5Pw30ov2a6KDDj1N4lNQc7hVcMDwi1LSdK/WPAAUTk5Cl99+/fU RbhRtEU7EzJggJ8XIB/iEroMBYKsjEQJD2LZpXMWUcyFzdH4vRkuOUVbryk1tBpC6mO1 aGXgvv7FNgxrghoagftl4NUMgbCmGBPjEGNj7VQnHbE9sRaBIFotOoc41Ra/EhtxS1Me afgw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=7IXzt0nzIOAJKG+GOlOHwpocfgEQHcHB3c85Qh1MbXQ=; b=EHgZB8KPVoJr4L8RM1mlwm+4yKnfhFDjOFcireB404s68xtQS2hzOq2gKV+26Fn4/W BbXIXN3fUFxm1xVZIa0xy35GofmdgBPSsSmXW2z/g0OPZ3DqrXpmCTc0D9raeXxNJovL TK1SHYGtFiwk4XwJNYTcIUVrTKhniVr7NU2AGOeQQa2WwJ+BtX8xfSbHf1eR3nI/1weX RvQWcytoSZIOKDa298qGbnaS8v9FEGWMU8W9Wwze1oeOljxCq1B8fZYcg/9BJV5iYR5Y QpNghVt1mBCuq55STeC9ohvwwfZjNyXFR2rp8+6lxEF6hDkKz4x+RSw3H+5UCWdiYfuE 3dAg== X-Gm-Message-State: APjAAAUM7DFNF4lA81hMl9n1a2aruOOiuI1FbtnW9LR/o5QuDYLO+bt9 E2ZTse5eZ4kQG7Qm4VziOCc00i61W2UuMq9QWh8= X-Google-Smtp-Source: APXvYqxHh9Vpw2/wvHMPDhyKGNC5V6yv/sLU15pYzCsQMLyNAS0NbwW4XefWh5XnZmWbNuAvdDPcbimsS+6ncV76MZw= X-Received: by 2002:a5b:543:: with SMTP id r3mr20871984ybp.462.1556017205279; Tue, 23 Apr 2019 04:00:05 -0700 (PDT) MIME-Version: 1.0 References: <20190423065024.12695-1-jencce.kernel@gmail.com> In-Reply-To: <20190423065024.12695-1-jencce.kernel@gmail.com> From: Amir Goldstein Date: Tue, 23 Apr 2019 13:59:53 +0300 Message-ID: Subject: Re: [PATCH] ovl: add RWF_NONITIFY flag to skip wrong duplicate fanotify event To: Murphy Zhou Cc: Miklos Szeredi , overlayfs , linux-fsdevel , Amir Goldstein Content-Type: multipart/mixed; boundary="000000000000c91d620587307ceb" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org --000000000000c91d620587307ceb Content-Type: text/plain; charset="UTF-8" On Tue, Apr 23, 2019 at 9:51 AM Murphy Zhou wrote: > > Overlays ovl_iter_write calls vfs_iter_write to write on real file, > in which calls fsnotify_modify on this change, however vfs_write also > calls fsnotify_modify after ovl_iter_write. The first notification > sent by vfs_iter_write grabs marks from upper inode and overlay mnt, > because of its fake path. The second one sent by vfs_write grabs marks > from ovl inode and ovl mnt. > > LTP fanotify06 add modify mark for mnt point, then add ignore modify > mask on testfile, then truncate and write the file. Because the ignore > mask is marked on ovl inode, not the upper inode, the first event is not > masked like the second one. So we get a modification event even with a > mask on the file. Care to extend fanotify06 in a similar manner to the way readahead02 was extended to test overlay test case regardless of the base LTP filesystem? > > Proposing fixing this by add a new RWF flag to skip fsnotify on this IO. > vfs_iter_write used by ovl can use this flag to skip one duplicate event. > This fix is wrong for several reasons: - It exports RWF_NONOTIFY to uapi - It will cause no events at all when overlay writes to file even when user requested events on upper inode Please try attached patch. Thanks, Amir. > Signed-off-by: Murphy Zhou > --- > fs/overlayfs/file.c | 2 +- > fs/read_write.c | 2 +- > include/uapi/linux/fs.h | 5 ++++- > 3 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c > index 84dd957efa24..0827199a5311 100644 > --- a/fs/overlayfs/file.c > +++ b/fs/overlayfs/file.c > @@ -242,7 +242,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) > old_cred = ovl_override_creds(file_inode(file)->i_sb); > file_start_write(real.file); > ret = vfs_iter_write(real.file, iter, &iocb->ki_pos, > - ovl_iocb_to_rwf(iocb)); > + ovl_iocb_to_rwf(iocb)|RWF_NONOTIFY); > file_end_write(real.file); > revert_creds(old_cred); > > diff --git a/fs/read_write.c b/fs/read_write.c > index 61b43ad7608e..aec751cacedf 100644 > --- a/fs/read_write.c > +++ b/fs/read_write.c > @@ -957,7 +957,7 @@ static ssize_t do_iter_write(struct file *file, struct iov_iter *iter, > ret = do_iter_readv_writev(file, iter, pos, WRITE, flags); > else > ret = do_loop_readv_writev(file, iter, pos, WRITE, flags); > - if (ret > 0) > + if (ret > 0 && !(flags & RWF_NONOTIFY)) > fsnotify_modify(file); > return ret; > } > diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h > index 121e82ce296b..103f1a9375f2 100644 > --- a/include/uapi/linux/fs.h > +++ b/include/uapi/linux/fs.h > @@ -342,8 +342,11 @@ typedef int __bitwise __kernel_rwf_t; > /* per-IO O_APPEND */ > #define RWF_APPEND ((__force __kernel_rwf_t)0x00000010) > > +/* do not notify this IO */ > +#define RWF_NONOTIFY ((__force __kernel_rwf_t)0x00000020) > + > /* mask of flags supported by the kernel */ > #define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\ > - RWF_APPEND) > + RWF_APPEND | RWF_NONOTIFY) > > #endif /* _UAPI_LINUX_FS_H */ > -- > 2.21.0 > --000000000000c91d620587307ceb Content-Type: text/plain; charset="US-ASCII"; name="0001-ovl-use-real-path-for-open_with_fake_path.patch.txt" Content-Disposition: attachment; filename="0001-ovl-use-real-path-for-open_with_fake_path.patch.txt" Content-Transfer-Encoding: base64 Content-ID: X-Attachment-Id: f_jutoe4h50 RnJvbSBjNTExYTEwM2JhNjY5MGNiZjY3NDhmMjU3MDBjYjhlOTVkZDc3OTgyIE1vbiBTZXAgMTcg MDA6MDA6MDAgMjAwMQpGcm9tOiBBbWlyIEdvbGRzdGVpbiA8YW1pcjczaWxAZ21haWwuY29tPgpE YXRlOiBUdWUsIDIzIEFwciAyMDE5IDEzOjExOjEwICswMzAwClN1YmplY3Q6IFtQQVRDSF0gb3Zs OiB1c2UgcmVhbCBwYXRoIGZvciBvcGVuX3dpdGhfZmFrZV9wYXRoKCkKCm92bF9vcGVuKCkgdXNl cyBvcGVuX3dpdGhfZmFrZV9wYXRoKCkgdG8gY3JlYXRlIGEgZmlsZSBvYmplY3Qgd2l0aCBhCmdp dmVuIHBhdGguICBDdXJyZW50bHkgb3ZlcmxheWZzIHVzZXMgdGhlIG92ZXJsYXkgcGF0aCBhcyB0 aGUgImZha2UiCnBhdGguIFRoaXMgY2F1c2VzIHNvbWUgaXNzdWVzIHdoZW4gVkZTIGNvZGUgcmVm ZXJzIHRvIGZpbGUtPmZfcGF0aC0+bW50LgoKT25lIGlzc3VlLCByZXBvcnRlZCBieSBNdXJwaHkg WmhvdSwgaXMgdGhhdCBmc25vdGlmeSBob29rcyBjaGVjawpmb3IgbW91bnQgbWFya3MgYWdhaW5z dCB0aGUgd3JvbmcgdmZzbW91bnQuCgpMaW5rOiBodHRwczovL2xvcmUua2VybmVsLm9yZy9saW51 eC1mc2RldmVsLzIwMTkwNDIzMDY1MDI0LjEyNjk1LTEtamVuY2NlLmtlcm5lbEBnbWFpbC5jb20v ClJlcG9ydGVkLWJ5OiBNdXJwaHkgWmhvdSA8amVuY2NlLmtlcm5lbEBnbWFpbC5jb20+ClNpZ25l ZC1vZmYtYnk6IEFtaXIgR29sZHN0ZWluIDxhbWlyNzNpbEBnbWFpbC5jb20+Ci0tLQogZnMvb3Zl cmxheWZzL2ZpbGUuYyB8IDUgKysrKy0KIDEgZmlsZSBjaGFuZ2VkLCA0IGluc2VydGlvbnMoKyks IDEgZGVsZXRpb24oLSkKCmRpZmYgLS1naXQgYS9mcy9vdmVybGF5ZnMvZmlsZS5jIGIvZnMvb3Zl cmxheWZzL2ZpbGUuYwppbmRleCBkZGZkOTNmMTNjYzUuLmVjOWY4NzYzZmUwOCAxMDA2NDQKLS0t IGEvZnMvb3ZlcmxheWZzL2ZpbGUuYworKysgYi9mcy9vdmVybGF5ZnMvZmlsZS5jCkBAIC0yOCwx MCArMjgsMTMgQEAgc3RhdGljIHN0cnVjdCBmaWxlICpvdmxfb3Blbl9yZWFsZmlsZShjb25zdCBz dHJ1Y3QgZmlsZSAqZmlsZSwKIHsKIAlzdHJ1Y3QgaW5vZGUgKmlub2RlID0gZmlsZV9pbm9kZShm aWxlKTsKIAlzdHJ1Y3QgZmlsZSAqcmVhbGZpbGU7CisJc3RydWN0IHBhdGggcmVhbHBhdGg7CiAJ Y29uc3Qgc3RydWN0IGNyZWQgKm9sZF9jcmVkOwogCisJb3ZsX3BhdGhfcmVhbChmaWxlX2RlbnRy eShmaWxlKSwgJnJlYWxwYXRoKTsKKwogCW9sZF9jcmVkID0gb3ZsX292ZXJyaWRlX2NyZWRzKGlu b2RlLT5pX3NiKTsKLQlyZWFsZmlsZSA9IG9wZW5fd2l0aF9mYWtlX3BhdGgoJmZpbGUtPmZfcGF0 aCwgZmlsZS0+Zl9mbGFncyB8IE9fTk9BVElNRSwKKwlyZWFsZmlsZSA9IG9wZW5fd2l0aF9mYWtl X3BhdGgoJnJlYWxwYXRoLCBmaWxlLT5mX2ZsYWdzIHwgT19OT0FUSU1FLAogCQkJCSAgICAgICBy ZWFsaW5vZGUsIGN1cnJlbnRfY3JlZCgpKTsKIAlyZXZlcnRfY3JlZHMob2xkX2NyZWQpOwogCi0t IAoyLjE3LjEKCg== --000000000000c91d620587307ceb--