Commit 7e3d2c82 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag '5.4-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6 

Pull cifs updates from Steve French:
 "Various cifs/smb3 fixes (including for share deleted cases) and
  features including improved encrypted read performance, and various
  debugging improvements.

  Note that since I am at a test event this week with the Samba team,
  and at the annual Storage Developer Conference/SMB3 Plugfest test
  event next week a higher than usual number of fixes is expected later
  next week as other features in progress get additional testing and
  review during these two events"

* tag '5.4-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6: (38 commits)
  cifs: update internal module version number
  cifs: modefromsid: write mode ACE first
  cifs: cifsroot: add more err checking
  smb3: add missing worker function for SMB3 change notify
  cifs: Add support for root file systems
  cifs: modefromsid: make room for 4 ACE
  smb3: fix potential null dereference in decrypt offload
  smb3: fix unmount hang in open_shroot
  smb3: allow disabling requesting leases
  smb3: improve handling of share deleted (and share recreated)
  smb3: display max smb3 requests in flight at any one time
  smb3: only offload decryption of read responses if multiple requests
  cifs: add a helper to find an existing readable handle to a file
  smb3: enable offload of decryption of large reads via mount option
  smb3: allow parallelizing decryption of reads
  cifs: add a debug macro that prints \\server\share for errors
  smb3: fix signing verification of large reads
  smb3: allow skipping signature verification for perf sensitive configurations
  smb3: add dynamic tracepoints for flush and close
  smb3: log warning if CSC policy conflicts with cache mount option
  ...
parents 7a0d7961 4d6bcba7

Documentation/filesystems/cifs/cifsroot.txt

0 → 100644
+97 −0
Original line number Diff line number Diff line 
Mounting root file system via SMB (cifs.ko)

===========================================



Written 2019 by Paulo Alcantara <palcantara@suse.de>

Written 2019 by Aurelien Aptel <aaptel@suse.com>



The CONFIG_CIFS_ROOT option enables experimental root file system

support over the SMB protocol via cifs.ko.



It introduces a new kernel command-line option called 'cifsroot='

which will tell the kernel to mount the root file system over the

network by utilizing SMB or CIFS protocol.



In order to mount, the network stack will also need to be set up by

using 'ip=' config option. For more details, see

Documentation/filesystems/nfs/nfsroot.txt.



A CIFS root mount currently requires the use of SMB1+UNIX Extensions

which is only supported by the Samba server. SMB1 is the older

deprecated version of the protocol but it has been extended to support

POSIX features (See [1]). The equivalent extensions for the newer

recommended version of the protocol (SMB3) have not been fully

implemented yet which means SMB3 doesn't support some required POSIX

file system objects (e.g. block devices, pipes, sockets).



As a result, a CIFS root will default to SMB1 for now but the version

to use can nonetheless be changed via the 'vers=' mount option.  This

default will change once the SMB3 POSIX extensions are fully

implemented.



Server configuration

====================



To enable SMB1+UNIX extensions you will need to set these global

settings in Samba smb.conf:



    [global]

    server min protocol = NT1

    unix extension = yes        # default



Kernel command line

===================



root=/dev/cifs



This is just a virtual device that basically tells the kernel to mount

the root file system via SMB protocol.



cifsroot=//<server-ip>/<share>[,options]



Enables the kernel to mount the root file system via SMB that are

located in the <server-ip> and <share> specified in this option.



The default mount options are set in fs/cifs/cifsroot.c.



server-ip

	IPv4 address of the server.



share

	Path to SMB share (rootfs).



options

	Optional mount options. For more information, see mount.cifs(8).



Examples

========



Export root file system as a Samba share in smb.conf file.



...

[linux]

	path = /path/to/rootfs

	read only = no

	guest ok = yes

	force user = root

	force group = root

	browseable = yes

	writeable = yes

	admin users = root

	public = yes

	create mask = 0777

	directory mask = 0777

...



Restart smb service.



# systemctl restart smb



Test it under QEMU on a kernel built with CONFIG_CIFS_ROOT and

CONFIG_IP_PNP options enabled.



# qemu-system-x86_64 -enable-kvm -cpu host -m 1024 \

  -kernel /path/to/linux/arch/x86/boot/bzImage -nographic \

  -append "root=/dev/cifs rw ip=dhcp cifsroot=//10.0.2.2/linux,username=foo,password=bar console=ttyS0 3"





1: https://wiki.samba.org/index.php/UNIX_Extensions

fs/cifs/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -211,3 +211,11 @@ config CIFS_FSCACHE 
	  Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data

	  to be cached locally on disk through the general filesystem cache

	  manager. If unsure, say N.



config CIFS_ROOT

	bool "SMB root file system (Experimental)"

	depends on CIFS=y && IP_PNP

	help

	  Enables root file system support over SMB protocol.



	  Most people say N here.

fs/cifs/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -21,3 +21,5 @@ cifs-$(CONFIG_CIFS_DFS_UPCALL) += dns_resolve.o cifs_dfs_ref.o dfs_cache.o 
cifs-$(CONFIG_CIFS_FSCACHE) += fscache.o cache.o



cifs-$(CONFIG_CIFS_SMB_DIRECT) += smbdirect.o



cifs-$(CONFIG_CIFS_ROOT) += cifsroot.o

fs/cifs/cifs_debug.c

+2 −0
Original line number Diff line number Diff line
@@ -452,6 +452,7 @@ static ssize_t cifs_stats_proc_write(struct file *file, 
		list_for_each(tmp1, &cifs_tcp_ses_list) {

			server = list_entry(tmp1, struct TCP_Server_Info,

					    tcp_ses_list);

			server->max_in_flight = 0;

#ifdef CONFIG_CIFS_STATS2

			for (i = 0; i < NUMBER_OF_SMB2_COMMANDS; i++) {

				atomic_set(&server->num_cmds[i], 0);
@@ -526,6 +527,7 @@ static int cifs_stats_proc_show(struct seq_file *m, void *v) 
	list_for_each(tmp1, &cifs_tcp_ses_list) {

		server = list_entry(tmp1, struct TCP_Server_Info,

				    tcp_ses_list);

		seq_printf(m, "\nMax requests in flight: %d", server->max_in_flight);

#ifdef CONFIG_CIFS_STATS2

		seq_puts(m, "\nTotal time spent processing by command. Time ");

		seq_printf(m, "units are jiffies (%d per second)\n", HZ);

fs/cifs/cifs_debug.h

+67 −0
Original line number Diff line number Diff line
@@ -80,6 +80,60 @@ do { \ 
			type, fmt, ##__VA_ARGS__);	\

} while (0)



#define cifs_server_dbg_func(ratefunc, type, fmt, ...)		\

do {								\

	const char *sn = "";					\

	if (server && server->hostname)				\

		sn = server->hostname;				\

	if ((type) & FYI && cifsFYI & CIFS_INFO) {		\

		pr_debug_ ## ratefunc("%s: \\\\%s "	fmt,	\

			__FILE__, sn, ##__VA_ARGS__);		\

	} else if ((type) & VFS) {				\

		pr_err_ ## ratefunc("CIFS VFS: \\\\%s " fmt,	\

			sn, ##__VA_ARGS__);			\

	} else if ((type) & NOISY && (NOISY != 0)) {		\

		pr_debug_ ## ratefunc("\\\\%s " fmt,		\

			sn, ##__VA_ARGS__);			\

	}							\

} while (0)



#define cifs_server_dbg(type, fmt, ...)			\

do {							\

	if ((type) & ONCE)				\

		cifs_server_dbg_func(once,		\

			type, fmt, ##__VA_ARGS__);	\

	else						\

		cifs_server_dbg_func(ratelimited,	\

			type, fmt, ##__VA_ARGS__);	\

} while (0)



#define cifs_tcon_dbg_func(ratefunc, type, fmt, ...)		\

do {								\

	const char *tn = "";					\

	if (tcon && tcon->treeName)				\

		tn = tcon->treeName;				\

	if ((type) & FYI && cifsFYI & CIFS_INFO) {		\

		pr_debug_ ## ratefunc("%s: %s "	fmt,		\

			__FILE__, tn, ##__VA_ARGS__);		\

	} else if ((type) & VFS) {				\

		pr_err_ ## ratefunc("CIFS VFS: %s " fmt,	\

			tn, ##__VA_ARGS__);			\

	} else if ((type) & NOISY && (NOISY != 0)) {		\

		pr_debug_ ## ratefunc("%s " fmt,		\

			tn, ##__VA_ARGS__);			\

	}							\

} while (0)



#define cifs_tcon_dbg(type, fmt, ...)			\

do {							\

	if ((type) & ONCE)				\

		cifs_tcon_dbg_func(once,		\

			type, fmt, ##__VA_ARGS__);	\

	else						\

		cifs_tcon_dbg_func(ratelimited,	\

			type, fmt, ##__VA_ARGS__);	\

} while (0)



/*

 *	debug OFF

 *	---------
@@ -91,6 +145,19 @@ do { \ 
		pr_debug(fmt, ##__VA_ARGS__);				\

} while (0)



#define cifs_server_dbg(type, fmt, ...)					\

do {									\

	if (0)								\

		pr_debug("\\\\%s " fmt,					\

			 server->hostname, ##__VA_ARGS__);		\

} while (0)



#define cifs_tcon_dbg(type, fmt, ...)					\

do {									\

	if (0)								\

		pr_debug("%s " fmt, tcon->treeName, ##__VA_ARGS__);	\

} while (0)



#define cifs_info(fmt, ...)						\

do {									\

	pr_info("CIFS: "fmt, ##__VA_ARGS__);				\

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