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 9613233DEF7 for ; Wed, 24 Jun 2026 16:49:18 +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=1782319759; cv=none; b=ljxcdLfuF7CUJ9xTrESoxnLFBAe7sBn6F9Fm/6Y0y5oQyet68xP/U1XV/gPagR81NRUOtl3NQQYy201vH4xOwOHttMxBiIyIsP/+65FQ8ptPr9SQsZsUUIoFaQKr3juTphmJhLaBchc7DxaMB3AixtVva7xJslaLuAnyrRI0zDs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782319759; c=relaxed/simple; bh=X6kevZraK1RR6FVOJLEifcAgcM7lQtKM8zuaD58jkBA=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=SDREnpC2k8olDt79Nha2hzq+Bknh4J7fx8cm+ajeqQtPz1DD27Ly7Yka4lcj4qKwabIWfyiJewrbNmuj47yQlNzPvjCcN118e9Xrf30isO3oanAqqiM8ML60BV4f0u9+1jtbeUGpaW/F2eRFujG8k4lJa8lJ9W6//GPHY1NHJqw= 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=ZAVwsmye; 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="ZAVwsmye" Received: by mail-qk1-f202.google.com with SMTP id af79cd13be357-9158f2c4b55so153955385a.0 for ; Wed, 24 Jun 2026 09:49:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1782319758; x=1782924558; 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=ZAVwsmyejjRcPYAY5Lo3WVGsdo99bR3Jy+fkjxUvceuM2KJ5OOuPdBnHyk5p+nlTrv 76d5cEAA5mpb5gnupZ8Nt98HsdxVLjH8mIS6RSJQhr+Vg4cegCDcQ3Ew3ZbGyGB6Bc0q Z1laidWDOKkIwl/iuDXIhTPq+thvZxNWNWSoFqelgEXCqGqK7Wub+NrCeDgEmY9Yrw7T +wrPY76wq5RPYLPl6H4/wO0T9hFVH+/4Vqv9KdC/tV2cRLhC92X90DSNDqW5Vg9BsoX7 MovQ958s7V6k3T+ljDl9ifMOilozbz8ij0lCdFRQRm5bufS/GCTNPBGffhwQ8cmIYX4J vbnw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782319758; x=1782924558; 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=I1NwegdFIUCd6meDTX2tc7ABs0kJrpSooTlWbATzhH6RTfffKfwSHvaukzFx8lz0rp HfyQuYufIVWK4WYw0K1qgmPyVKGykeTzmjqnVCgMdnHS/LOVm/PQBExYamsAyFoWgIZX CzqIhGNsDfxGoOId5IlCktg/Y+FqC/VXFapw4cn904avj2Jn20VJ68Sqcfj1HAdiVYXy 4/7F2GHEIUf6h8dw2As/o3YvdT5SdYteHwMZ+H0vjaqJtGaLuSOlf6kMCO8CjHcRsC3n ov9D7bw1bLABt2Zadoim6R3rfzFGZIefFpFQIjP+xlBV1WPcVAw2jn+eCXNzT4YU3YNj Pjnw== X-Forwarded-Encrypted: i=1; AFNElJ+Kd/vHq3zfooz46QikMsFer9l3letSYByc0Gtd3bWmD3lFQa4g3K0VywzOjzt3Je6dOw4xkdkXPROvCNI=@vger.kernel.org X-Gm-Message-State: AOJu0YyoqSv5xecCnDujFA8vD/7tCc6fLDWTL+5JQ4Y7I9laMwYjGKG1 4GxKr1KoztX4q1XUgX7vKsWwptSi+bMrtMwKCwRp0KZeEBT9oQYdY/z9KfAHeP2xmgFqraLYVQ= = X-Received: from qknqj4.prod.google.com ([2002:a05:620a:8804:b0:915:96da:f339]) (user=brho job=prod-delivery.src-stubby-dispatcher) by 2002:a05:620a:4445:b0:917:fcec:cfe0 with SMTP id af79cd13be357-921d29f7718mr3068174685a.33.1782319757250; Wed, 24 Jun 2026 09:49:17 -0700 (PDT) Date: Wed, 24 Jun 2026 16:48:49 +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.rc0.799.gd6f94ed593-goog Message-ID: <20260624164906.2877282-1-brho@google.com> Subject: 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