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Revision 4860abb91f3d7fbaf8147d54782149bb1fc45892 authored by Steve French on 06 February 2024, 22:34:22 UTC, committed by Steve French on 16 February 2024, 04:19:23 UTC 
smb: Fix regression in writes when non-standard maximum write size negotiated
 
The conversion to netfs in the 6.3 kernel caused a regression when
maximum write size is set by the server to an unexpected value which is
not a multiple of 4096 (similarly if the user overrides the maximum
write size by setting mount parm "wsize", but sets it to a value that
is not a multiple of 4096).  When negotiated write size is not a
multiple of 4096 the netfs code can skip the end of the final
page when doing large sequential writes, causing data corruption.

This section of code is being rewritten/removed due to a large
netfs change, but until that point (ie for the 6.3 kernel until now)
we can not support non-standard maximum write sizes.

Add a warning if a user specifies a wsize on mount that is not
a multiple of 4096 (and round down), also add a change where we
round down the maximum write size if the server negotiates a value
that is not a multiple of 4096 (we also have to check to make sure that
we do not round it down to zero).

Reported-by: R. Diez" <rdiez-2006@rd10.de>
Fixes: d08089f649a0 ("cifs: Change the I/O paths to use an iterator rather than a page list")
Suggested-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Acked-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Tested-by: Matthew Ruffell <matthew.ruffell@canonical.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org # v6.3+
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
1 parent 8bde59b
Raw File
netdev-notifier-error-inject.c 
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>

#include "notifier-error-inject.h"

static int priority;
module_param(priority, int, 0);
MODULE_PARM_DESC(priority, "specify netdevice notifier priority");

static struct notifier_err_inject netdev_notifier_err_inject = {
	.actions = {
		{ NOTIFIER_ERR_INJECT_ACTION(NETDEV_REGISTER) },
		{ NOTIFIER_ERR_INJECT_ACTION(NETDEV_CHANGEMTU) },
		{ NOTIFIER_ERR_INJECT_ACTION(NETDEV_CHANGENAME) },
		{ NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRE_UP) },
		{ NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRE_TYPE_CHANGE) },
		{ NOTIFIER_ERR_INJECT_ACTION(NETDEV_POST_INIT) },
		{ NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRECHANGEMTU) },
		{ NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRECHANGEUPPER) },
		{ NOTIFIER_ERR_INJECT_ACTION(NETDEV_CHANGEUPPER) },
		{}
	}
};

static struct dentry *dir;

static int netdev_err_inject_init(void)
{
	int err;

	dir = notifier_err_inject_init("netdev", notifier_err_inject_dir,
				       &netdev_notifier_err_inject, priority);
	if (IS_ERR(dir))
		return PTR_ERR(dir);

	err = register_netdevice_notifier(&netdev_notifier_err_inject.nb);
	if (err)
		debugfs_remove_recursive(dir);

	return err;
}

static void netdev_err_inject_exit(void)
{
	unregister_netdevice_notifier(&netdev_notifier_err_inject.nb);
	debugfs_remove_recursive(dir);
}

module_init(netdev_err_inject_init);
module_exit(netdev_err_inject_exit);

MODULE_DESCRIPTION("Netdevice notifier error injection module");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Nikolay Aleksandrov <razor@blackwall.org>");
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