From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f202.google.com (mail-qk1-f202.google.com [209.85.222.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8F6BC47DF80 for ; Thu, 2 Jul 2026 09:09:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782983397; cv=none; b=cEGUm5AdTDjs1r8y0ljYLSThKBeKEeDzqTC2p60IngkO7IdO75KRmQzXIl9zcG0nVwcekg9SiSN3I8G2SH2it9kuiF0KIO/aIcJuVn0duK1sjQyVxMzZOzsYva3fEuPL15VZsaUlmFk0huURW1jy3erghS+yfpw97Ztyc2gbtwY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782983397; c=relaxed/simple; bh=X6kevZraK1RR6FVOJLEifcAgcM7lQtKM8zuaD58jkBA=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=IlHKN2deo3E/X4e9eCBgXX9qWtaWn5tdW3fXmQuG1+ammxpdVu09e9UFGA+vV97YWITgNSIz3XylmZ9oRkSuWy3tANcDO6QQ/wKwefhniPP1276WFLfZd3y9Vs27xIhnEA8PMWcvqu53GOBowBziFHDwzi5bwVmhdHLtUJYXcLw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--brho.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=qlTGj2dm; arc=none smtp.client-ip=209.85.222.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--brho.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="qlTGj2dm" Received: by mail-qk1-f202.google.com with SMTP id af79cd13be357-92e663c29f2so46105285a.0 for ; Thu, 02 Jul 2026 02:09:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1782983396; x=1783588196; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=9OEIsKx1YFXUdwec7xn+GP5SEzXKOgSZ1HtddneFwhs=; b=qlTGj2dmId8oson1TLoYecHiQc6MiTPhtlRvgdIlOc0CDEnS0KubG5VYdBg+NTm0dl al5TTJQ9mB4+knc6SYIG8eF0r40adAxih91nL2hMJ3++KZ+p7FKq4/Pl0h6ZGu64L+LB cgxbhR68mKmKZ9Kpk5Xy73fKrwgbJ23tmt52IPRw9lpsn9MWunmVVYrBKxAiklpqajTT ZgzsCyItocOAa+Xs6Ocyh1B5v4fpSS4dlT66xM6k+qIORQLvx5zirx3fCrahzANs/dsW TYvh9lOePWO74v7PO8ZnW/rv+/lO8B+i3TuK7gWukQHi8b+yWsuosj0sCFTRPru6u3Rm ahMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782983396; x=1783588196; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=9OEIsKx1YFXUdwec7xn+GP5SEzXKOgSZ1HtddneFwhs=; b=EAMeU5w1Xuvw0nRr9gM64sTLNv+lpxTeNfObB8rJoswKDq0vY/VOTtffLIs1pEHZ98 UolsCyadkFQka3RmAAu5RmUtno2xYA5ylEtQ9lmWPUF2/+Gzgmr2zPWjk8lvOmh7LIvt pOILrqetN3KqvPIl4D67XSmtys/p3ZtkV6K/CRTpGSfzkk7vQQP1zD1lB14FEzGHxCks FEmxxQh2g3VfcDqJ17kBU+KP28dxcdfLcuLSNWlQXTgiI+sSrS16EfREHXrjuplU2TG9 mgZHcRTGbdhT4B7N2kmxQXrbMDO/v/qaMrUzsqlyoS5pIlll5d+8SiYwlFfCF2gjKQaY Z9MQ== X-Forwarded-Encrypted: i=1; AFNElJ+9uw+FS3V3hkxsTOiJjaQ2TiMV9bnwuUU/76HsePknQkl7Ru5ucI4+fFE8RPy+I17Oq0upikeGzKMic08=@vger.kernel.org X-Gm-Message-State: AOJu0Yyux/Az69k7Sq0Ci3Ki6+6NwffzruIB7nIaekiX0K4dd9XAuA3S Ae92ppT6NDfTaAo0ajxgyhX7n3QMdvvsbP2iztt+DQPwOJx7JmMT0j1s52v7fJQO+5uhxGxq1A= = X-Received: from qkd12.prod.google.com ([2002:a05:620a:a00c:b0:92e:6be9:84d2]) (user=brho job=prod-delivery.src-stubby-dispatcher) by 2002:a05:620a:444f:b0:90f:786c:4a82 with SMTP id af79cd13be357-92e69836085mr1262935885a.39.1782983395404; Thu, 02 Jul 2026 02:09:55 -0700 (PDT) Date: Thu, 2 Jul 2026 09:09:32 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.55.0.rc2.803.g1fd1e6609c-goog Message-ID: <20260702090941.1298188-1-brho@google.com> Subject: [PATCH] 9p: treat read return values of 0 as EOF From: Barret Rhoden To: Eric Van Hensbergen , Latchesar Ionkov , Dominique Martinet , Christian Schoenebeck , David Howells Cc: v9fs@lists.linux.dev, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" If your 9p server shares a synthetic file system such as sysfs, the file size from stat often disagrees with the actual file size. Treat non-error reads of 0 as EOF, except in the case where the request was for 0 bytes. Tested: git@github.com:hugelgupf/p9.git, served "/" on 10.0.2.2 bash-5.3# mount -t 9p -o trans=tcp,port=12345,cache=none 10.0.2.2 /tmp/foo bash-5.3# cat /tmp/foo/sys/devices/system/cpu/online 0-47 Fixes: eb497943fa21 ("9p: Convert to using the netfs helper lib to do reads and caching") Signed-off-by: Barret Rhoden --- fs/9p/vfs_addr.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c index 1ac0b3dcc077..df420b061664 100644 --- a/fs/9p/vfs_addr.c +++ b/fs/9p/vfs_addr.c @@ -73,6 +73,7 @@ static void v9fs_issue_read(struct netfs_io_subrequest *subreq) char *target; unsigned long long pos = subreq->start + subreq->transferred; int total = 0, err, len, n; + size_t to_read = iov_iter_count(&subreq->io_iter); if (S_ISLNK(rreq->inode->i_mode)) { /* p9_client_readlink() must not be called for legacy protocols @@ -105,6 +106,8 @@ static void v9fs_issue_read(struct netfs_io_subrequest *subreq) __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags); if (pos + total >= i_size_read(rreq->inode)) __set_bit(NETFS_SREQ_HIT_EOF, &subreq->flags); + if (!err && !total && to_read) + __set_bit(NETFS_SREQ_HIT_EOF, &subreq->flags); if (!err && total) { subreq->transferred += total; __set_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags); -- 2.55.0.rc0.799.gd6f94ed593-goog