From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794591559; b=dA1FCaJmSOjSOMuY/uVI26QrU6dfmXzcI/vzsoSqY9ERDmKKNrPNYl31QAzkv3bMRPZR hbCT24vgZXK3lRVBb+JRjmn4E0m4uDQ7eFPHocypOZt70MizE9i/pcsdglPEJKsSVXwSs JE1azEd46h0KMfv3I+GK5/NWVCWv1bMhF2bZ8ksuV+oadMzYK38BpjYjrcZZ6k0tfX3R3 KhURChyxBmEgtpHCIq2oZfbZBOAacRXFX+ptfUZZkmKDaI/Xw/EBgmvpRENa8xQp/08sC 0bhou6LH4A4lV0JicSZwV955vQxKX4F8Ar0YJsRQO1BMA4bt4q56fH8rs/7+ph7OPaA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591559; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=vt/pEqEV4Ze1PApSrc6JPObeKAG5So8mdGEh7MoXoNg=; b=GjlHxOn6/rqNQm5iNHOvcRF/gQso6mQtHct3WNA7o0Dvte/qb1eswWgIW/i2ugwSDIwQ jKql/gxBg9hTUBhQRFfYRBx/Xiz7CqIjmpPdVvNFveXfTImZpvACDX1Ma6rMmx5nvN5g+ nud9P3Xh6UBEQPOV+YEd2ru2652D0jlzommp3xHYcv3fvnbWgfRo3XLcQAkj9VkYFR12S nHoGjsWb3Y2BmyvUFHnaUjiL83QorWlHWtjrySNXftHf3i+moKV8W3JlHFOO1isPYU1ps DpUWxFjdJye+xrspVClVxTqW+4YcTQ6nqUmenBl/PxoHrtGTBmFeyKZZXGtUX7PPDxA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Eo19dYUo; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 69945606E228; Fri, 13 Nov 2026 17:39:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Eo19dYUo Received: by smtp.kernel.org (Postfix) with ESMTPSA id C119C1F000C4; Fri, 13 Nov 2026 17:39:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794591559; bh=vt/pEqEV4Ze1PApSrc6JPObeKAG5So8mdGEh7MoXoNg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Eo19dYUoSGDJ175x5bplfezJHCMGg8y3WypED4CaGsqLDxVSmIPDT9ewyS1zi/z+R vNIZkakOAbg7YcWVTfiwiYcLsX97EEJ4TlhQ20MjK+N2nrH7i1QrRSZRHSPA2HQxKs tUE00+3i/PiQ9oCI3mXVA8zJ23aus4qxHDL+rW9o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chi Zhiling , Namjae Jeon , Sasha Levin Subject: [PATCH 6.12 568/670] exfat: advance valid_size to EOF for append writes Date: Fri, 13 Nov 2026 10:52:12 -0500 Message-ID: <20261113153831.117386379@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153811.177190860@linuxfoundation.org> References: <20261113153811.177190860@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chi Zhiling [ Upstream commit b70ab407503706289163dd59f1ac3e942bacc37d ] For an append write, the write position is recalculated by generic_write_checks(). Therefore, the write position must be obtained after generic_write_checks() returns. Using the original write position to advance valid_size may cause the valid_size update to be skipped, potentially exposing stale data. Also move the truncate_pagecache() check below the recalculated position, so that pos is never read before it is assigned. Fixes: 11a347fb6cef ("exfat: change to get file size from DataLength") Cc: stable@vger.kernel.org Signed-off-by: Chi Zhiling Signed-off-by: Namjae Jeon [ sashal: moved pos initialization before the existing direct I/O alignment checks ] Signed-off-by: Sasha Levin --- fs/exfat/file.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/fs/exfat/file.c b/fs/exfat/file.c index 033852efe5dc3..b624dc527f675 100644 --- a/fs/exfat/file.c +++ b/fs/exfat/file.c @@ -581,23 +581,18 @@ static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter) struct file *file = iocb->ki_filp; struct inode *inode = file_inode(file); struct exfat_inode_info *ei = EXFAT_I(inode); - loff_t pos = iocb->ki_pos; - loff_t valid_size; + loff_t pos, valid_size; if (unlikely(exfat_forced_shutdown(inode->i_sb))) return -EIO; inode_lock(inode); - if (pos > i_size_read(inode)) - truncate_pagecache(inode, i_size_read(inode)); - - valid_size = ei->valid_size; - ret = generic_write_checks(iocb, iter); if (ret <= 0) goto unlock; + pos = iocb->ki_pos; if (iocb->ki_flags & IOCB_DIRECT) { unsigned long align = pos | iov_iter_alignment(iter); @@ -608,6 +603,10 @@ static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter) } } + if (pos > i_size_read(inode)) + truncate_pagecache(inode, i_size_read(inode)); + + valid_size = ei->valid_size; if (pos > valid_size) { ret = exfat_extend_valid_size(file, pos); if (ret < 0 && ret != -ENOSPC) { @@ -617,6 +616,8 @@ static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter) } if (ret < 0) goto unlock; + + pos = valid_size; } ret = __generic_file_write_iter(iocb, iter); @@ -625,9 +626,6 @@ static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter) inode_unlock(inode); - if (pos > valid_size) - pos = valid_size; - if (iocb->ki_pos > pos) { ssize_t err = generic_write_sync(iocb, iocb->ki_pos - pos); if (err < 0) -- 2.53.0