From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 809C2418A26 for ; Mon, 27 Jul 2026 13:40:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785159630; cv=none; b=kMp5xmXU5xj/v6gYTgzpmvtbTmO/dSKmmfHlSLRaowsCvPuijWRRHl1tD6e+IBbVbu/DU6dc0TAK5nJa6tir3UyJCONtxpgQRKGy3bN45j+YuLHDMJqQ2RIvxUC0MhL4914cltQEAnqoSKLkoWkB/GIaVH4ltk9lPpYRLe9ssPc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785159630; c=relaxed/simple; bh=L9DM3BMFdUTYEiBrBglMUuvUHtFEX+6wI/Bzr17JIUU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=c/yGOfsR0oJvm8Y8Y4ok6+uSmKCd9Ok7jFAbs/y3CekJSQtwH+b9D8Hju4Lgm6/QHCK2FxwxiOhjy6iK3Zx3gQqs2/RCxOK8NKkKUU1Iz7H2Q47DfuxHnTxy4ZSBShjzsUsfBGoouAR+t5ZDRQKESkefA2ENz3SqjyU7VYr11b4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mkE9zHb9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mkE9zHb9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 708D41F000E9; Mon, 27 Jul 2026 13:40:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785159629; bh=lfIT3NzWGIqRx4V5So+fbu9Yi81HFdjeJ7CsoX6hBqM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mkE9zHb9oPG4tC2ExfW3XZM1WK3PB2iIUI+di9rxRLfIAeGJfdGGvWa/LjrgkBFym A8Ya+C+SUsVoFqgjyfJLabtCD9lseFbjJbFF2gMvaQhLXojOfjWDFMMy4GQ/b3oK/z 4/gucUgA09S0qsEnPhLc/wZ9E9q3x932d9EDgPWeB44KQQ9B6h0kJtIsm3lnDiGYGe 5rMbl72ZRz8sT31JvvYos9+WptY86tMCtzfqgYK7LTAtomBgJlH1mkmI1T9s+NBPmH cTIpLc/2hHbumANouj0HDIhgbw8eVK4Blc0FqEZQ+o6lAuaBppmynhqO5N3qfG4j99 XHw3vcV2TM3bA== From: Sasha Levin To: stable@vger.kernel.org Cc: Souvik Banerjee , Amir Goldstein , Miklos Szeredi , "Christian Brauner (Amutable)" , Sasha Levin Subject: [PATCH 6.12.y] ovl: use linked upper dentry in copy-up tmpfile Date: Mon, 27 Jul 2026 09:40:26 -0400 Message-ID: <20260727134026.589031-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026072032-shine-duplicate-4a48@gregkh> References: <2026072032-shine-duplicate-4a48@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Souvik Banerjee [ Upstream commit e348eecd4d8fa8d18a5157ff59f7be1dc59c5928 ] ovl_copy_up_tmpfile() stores the disconnected O_TMPFILE dentry as the overlay's upper dentry reference via ovl_inode_update(). vfs_tmpfile() allocated this dentry via d_alloc(parentpath->dentry, &slash_name), so d_name is "/" and d_parent is c->workdir. Local upper filesystems (ext4, btrfs, xfs, ...) immediately rename it to "#" via d_mark_tmpfile() inside their ->tmpfile() op; FUSE and virtiofs do not, so both fields stay that way. Neither identifies the destination directory and filename where ovl_do_link() actually linked the file. When the upper filesystem implements ->d_revalidate() (e.g. FUSE or virtiofs), ovl_revalidate_real() calls it with the dentry's parent inode and a snapshot of d_name. The server tries to look up "/" inside c->workdir, fails, and overlayfs reports -ESTALE. This causes persistent ESTALE errors for any file that was copied up via the tmpfile path, breaking dpkg, apt, and other tools that do rename-over-existing on overlayfs with a FUSE/virtiofs upper. Before commit 6b52243f633e ("ovl: fold copy-up helpers into callers"), the tmpfile copy-up path used a dedicated helper ovl_link_tmpfile() that captured the linked destination dentry returned by ovl_do_link(): err = ovl_do_link(temp, udir, upper); ... if (!err) *newdentry = dget(upper); and published it via ovl_inode_update(d_inode(c->dentry), newdentry). The fold inlined ovl_do_link() into ovl_copy_up_tmpfile() but dropped the dget(upper) capture, and rewrote the publish line as ovl_inode_update(d_inode(c->dentry), dget(temp)) — where temp is the disconnected O_TMPFILE dentry. Fix by keeping a reference to the linked destination dentry after ovl_do_link() succeeds, and publishing that dentry at the existing ovl_inode_update() call site. The non-tmpfile/workdir path continues to publish the renamed temporary dentry. Reproducer: - Mount overlayfs with virtiofs (or a FUSE fs whose server advertises FUSE_TMPFILE) as upper - Run: dpkg -i - Observe: "error installing new file '...': Stale file handle" Fixes: 6b52243f633e ("ovl: fold copy-up helpers into callers") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Souvik Banerjee Link: https://patch.msgid.link/20260501232735.2610824-1-souvik@amlalabs.com Reviewed-by: Amir Goldstein Reviewed-by: Miklos Szeredi Signed-off-by: Christian Brauner (Amutable) [ adapted scoped credential and creation helpers to explicit credential, locking, lookup, and cleanup handling ] Signed-off-by: Sasha Levin --- fs/overlayfs/copy_up.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 75e804bc152ccf..9aa8509b8407a8 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -864,7 +864,7 @@ static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c) { struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); struct inode *udir = d_inode(c->destdir); - struct dentry *temp, *upper; + struct dentry *temp, *upper, *newdentry = NULL; struct file *tmpfile; struct ovl_cu_creds cc; int err; @@ -901,6 +901,14 @@ static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c) err = PTR_ERR(upper); if (!IS_ERR(upper)) { err = ovl_do_link(ofs, temp, udir, upper); + if (!err) { + /* + * Record the linked dentry -- not the disconnected + * O_TMPFILE dentry -- so that ->d_revalidate() on + * the upper fs sees the real parent/name. + */ + newdentry = dget(upper); + } dput(upper); } inode_unlock(udir); @@ -916,7 +924,7 @@ static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c) if (!c->metacopy) ovl_set_upperdata(d_inode(c->dentry)); - ovl_inode_update(d_inode(c->dentry), dget(temp)); + ovl_inode_update(d_inode(c->dentry), newdentry); out: ovl_end_write(c->dentry); -- 2.53.0