android_kernel_xiaomi_sm8350/fs/cifs/cifs_debug.c

/*
 *   fs/cifs_debug.c
 *
 *   Copyright (C) International Business Machines  Corp., 2000,2005
 *
 *   Modified by Steve French (sfrench@us.ibm.com)
 *
 *   This program is free software;  you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program;  if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <asm/uaccess.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifsfs.h"

void
cifs_dump_mem(char *label, void *data, int length)
{
	int i, j;
	int *intptr = data;
	char *charptr = data;
	char buf[10], line[80];

	printk(KERN_DEBUG "%s: dump of %d bytes of data at 0x%p\n",
		label, length, data);
	for (i = 0; i < length; i += 16) {
		line[0] = 0;
		for (j = 0; (j < 4) && (i + j * 4 < length); j++) {
			sprintf(buf, " %08x", intptr[i / 4 + j]);
			strcat(line, buf);
		}
		buf[0] = ' ';
		buf[2] = 0;
		for (j = 0; (j < 16) && (i + j < length); j++) {
			buf[1] = isprint(charptr[i + j]) ? charptr[i + j] : '.';
			strcat(line, buf);
		}
		printk(KERN_DEBUG "%s\n", line);
	}
}

#ifdef CONFIG_CIFS_DEBUG2
void cifs_dump_detail(struct smb_hdr *smb)
{
	cERROR(1, ("Cmd: %d Err: 0x%x Flags: 0x%x Flgs2: 0x%x Mid: %d Pid: %d",
		  smb->Command, smb->Status.CifsError,
		  smb->Flags, smb->Flags2, smb->Mid, smb->Pid));
	cERROR(1, ("smb buf %p len %d", smb, smbCalcSize_LE(smb)));
}


void cifs_dump_mids(struct TCP_Server_Info *server)
{
	struct list_head *tmp;
	struct mid_q_entry *mid_entry;

	if (server == NULL)
		return;

	cERROR(1, ("Dump pending requests:"));
	spin_lock(&GlobalMid_Lock);
	list_for_each(tmp, &server->pending_mid_q) {
		mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
		cERROR(1, ("State: %d Cmd: %d Pid: %d Tsk: %p Mid %d",
			mid_entry->midState,
			(int)mid_entry->command,
			mid_entry->pid,
			mid_entry->tsk,
			mid_entry->mid));
#ifdef CONFIG_CIFS_STATS2
		cERROR(1, ("IsLarge: %d buf: %p time rcv: %ld now: %ld",
			mid_entry->largeBuf,
			mid_entry->resp_buf,
			mid_entry->when_received,
			jiffies));
#endif /* STATS2 */
		cERROR(1, ("IsMult: %d IsEnd: %d", mid_entry->multiRsp,
			  mid_entry->multiEnd));
		if (mid_entry->resp_buf) {
			cifs_dump_detail(mid_entry->resp_buf);
			cifs_dump_mem("existing buf: ",
				mid_entry->resp_buf, 62);
		}
	}
	spin_unlock(&GlobalMid_Lock);
}
#endif /* CONFIG_CIFS_DEBUG2 */

#ifdef CONFIG_PROC_FS
static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
{
	struct list_head *tmp, *tmp2, *tmp3;
	struct mid_q_entry *mid_entry;
	struct TCP_Server_Info *server;
	struct cifsSesInfo *ses;
	struct cifsTconInfo *tcon;
	int i;

	seq_puts(m,
		    "Display Internal CIFS Data Structures for Debugging\n"
		    "---------------------------------------------------\n");
	seq_printf(m, "CIFS Version %s\n", CIFS_VERSION);
	seq_printf(m, "Active VFS Requests: %d\n", GlobalTotalActiveXid);
	seq_printf(m, "Servers:");

	i = 0;
	read_lock(&cifs_tcp_ses_lock);
	list_for_each(tmp, &cifs_tcp_ses_list) {
		server = list_entry(tmp, struct TCP_Server_Info,
				    tcp_ses_list);
		i++;
		list_for_each(tmp2, &server->smb_ses_list) {
			ses = list_entry(tmp2, struct cifsSesInfo,
					 smb_ses_list);
			if ((ses->serverDomain == NULL) ||
				(ses->serverOS == NULL) ||
				(ses->serverNOS == NULL)) {
				seq_printf(m, "\nentry for %s not fully "
					   "displayed\n\t", ses->serverName);
			} else {
				seq_printf(m,
				    "\n%d) Name: %s  Domain: %s Mounts: %d OS:"
				    " %s  \n\tNOS: %s\tCapability: 0x%x\n\tSMB"
				    " session status: %d\t",
				i, ses->serverName, ses->serverDomain,
				ses->ses_count, ses->serverOS, ses->serverNOS,
				ses->capabilities, ses->status);
			}
			seq_printf(m, "TCP status: %d\n\tLocal Users To "
				   "Server: %d SecMode: 0x%x Req On Wire: %d",
				   server->tcpStatus, server->srv_count,
				   server->secMode,
				   atomic_read(&server->inFlight));

#ifdef CONFIG_CIFS_STATS2
			seq_printf(m, " In Send: %d In MaxReq Wait: %d",
				atomic_read(&server->inSend),
				atomic_read(&server->num_waiters));
#endif

			seq_puts(m, "\nMIDs:\n");

			spin_lock(&GlobalMid_Lock);
			list_for_each(tmp3, &server->pending_mid_q) {
				mid_entry = list_entry(tmp3, struct
					mid_q_entry,
					qhead);
				seq_printf(m, "State: %d com: %d pid:"
						" %d tsk: %p mid %d\n",
						mid_entry->midState,
						(int)mid_entry->command,
						mid_entry->pid,
						mid_entry->tsk,
						mid_entry->mid);
			}
			spin_unlock(&GlobalMid_Lock);
		}
	}
	read_unlock(&cifs_tcp_ses_lock);
	seq_putc(m, '\n');

	seq_puts(m, "Shares:");

	i = 0;
	read_lock(&GlobalSMBSeslock);
	list_for_each(tmp, &GlobalTreeConnectionList) {
		__u32 dev_type;
		i++;
		tcon = list_entry(tmp, struct cifsTconInfo, cifsConnectionList);
		dev_type = le32_to_cpu(tcon->fsDevInfo.DeviceType);
		seq_printf(m, "\n%d) %s Uses: %d ", i,
				 tcon->treeName, atomic_read(&tcon->useCount));
		if (tcon->nativeFileSystem) {
			seq_printf(m, "Type: %s ",
					 tcon->nativeFileSystem);
		}
		seq_printf(m, "DevInfo: 0x%x Attributes: 0x%x"
				 "\nPathComponentMax: %d Status: %d",
			    le32_to_cpu(tcon->fsDevInfo.DeviceCharacteristics),
			    le32_to_cpu(tcon->fsAttrInfo.Attributes),
			    le32_to_cpu(tcon->fsAttrInfo.MaxPathNameComponentLength),
			    tcon->tidStatus);
		if (dev_type == FILE_DEVICE_DISK)
			seq_puts(m, " type: DISK ");
		else if (dev_type == FILE_DEVICE_CD_ROM)
			seq_puts(m, " type: CDROM ");
		else
			seq_printf(m, " type: %d ", dev_type);

		if (tcon->need_reconnect)
			seq_puts(m, "\tDISCONNECTED ");
	}
	read_unlock(&GlobalSMBSeslock);

	seq_putc(m, '\n');

	/* BB add code to dump additional info such as TCP session info now */
	return 0;
}

static int cifs_debug_data_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, cifs_debug_data_proc_show, NULL);
}

static const struct file_operations cifs_debug_data_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= cifs_debug_data_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

#ifdef CONFIG_CIFS_STATS
static ssize_t cifs_stats_proc_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *ppos)
{
	char c;
	int rc;
	struct list_head *tmp;
	struct cifsTconInfo *tcon;

	rc = get_user(c, buffer);
	if (rc)
		return rc;

	if (c == '1' || c == 'y' || c == 'Y' || c == '0') {
		read_lock(&GlobalSMBSeslock);
#ifdef CONFIG_CIFS_STATS2
		atomic_set(&totBufAllocCount, 0);
		atomic_set(&totSmBufAllocCount, 0);
#endif /* CONFIG_CIFS_STATS2 */
		list_for_each(tmp, &GlobalTreeConnectionList) {
			tcon = list_entry(tmp, struct cifsTconInfo,
					cifsConnectionList);
			atomic_set(&tcon->num_smbs_sent, 0);
			atomic_set(&tcon->num_writes, 0);
			atomic_set(&tcon->num_reads, 0);
			atomic_set(&tcon->num_oplock_brks, 0);
			atomic_set(&tcon->num_opens, 0);
			atomic_set(&tcon->num_closes, 0);
			atomic_set(&tcon->num_deletes, 0);
			atomic_set(&tcon->num_mkdirs, 0);
			atomic_set(&tcon->num_rmdirs, 0);
			atomic_set(&tcon->num_renames, 0);
			atomic_set(&tcon->num_t2renames, 0);
			atomic_set(&tcon->num_ffirst, 0);
			atomic_set(&tcon->num_fnext, 0);
			atomic_set(&tcon->num_fclose, 0);
			atomic_set(&tcon->num_hardlinks, 0);
			atomic_set(&tcon->num_symlinks, 0);
			atomic_set(&tcon->num_locks, 0);
		}
		read_unlock(&GlobalSMBSeslock);
	}

	return count;
}

static int cifs_stats_proc_show(struct seq_file *m, void *v)
{
	int i;
	struct list_head *tmp;
	struct cifsTconInfo *tcon;

	seq_printf(m,
			"Resources in use\nCIFS Session: %d\n",
			sesInfoAllocCount.counter);
	seq_printf(m, "Share (unique mount targets): %d\n",
			tconInfoAllocCount.counter);
	seq_printf(m, "SMB Request/Response Buffer: %d Pool size: %d\n",
			bufAllocCount.counter,
			cifs_min_rcv + tcpSesAllocCount.counter);
	seq_printf(m, "SMB Small Req/Resp Buffer: %d Pool size: %d\n",
			smBufAllocCount.counter, cifs_min_small);
#ifdef CONFIG_CIFS_STATS2
	seq_printf(m, "Total Large %d Small %d Allocations\n",
				atomic_read(&totBufAllocCount),
				atomic_read(&totSmBufAllocCount));
#endif /* CONFIG_CIFS_STATS2 */

	seq_printf(m, "Operations (MIDs): %d\n", midCount.counter);
	seq_printf(m,
		"\n%d session %d share reconnects\n",
		tcpSesReconnectCount.counter, tconInfoReconnectCount.counter);

	seq_printf(m,
		"Total vfs operations: %d maximum at one time: %d\n",
		GlobalCurrentXid, GlobalMaxActiveXid);

	i = 0;
	read_lock(&GlobalSMBSeslock);
	list_for_each(tmp, &GlobalTreeConnectionList) {
		i++;
		tcon = list_entry(tmp, struct cifsTconInfo, cifsConnectionList);
		seq_printf(m, "\n%d) %s", i, tcon->treeName);
		if (tcon->need_reconnect)
			seq_puts(m, "\tDISCONNECTED ");
		seq_printf(m, "\nSMBs: %d Oplock Breaks: %d",
			atomic_read(&tcon->num_smbs_sent),
			atomic_read(&tcon->num_oplock_brks));
		seq_printf(m, "\nReads:  %d Bytes: %lld",
			atomic_read(&tcon->num_reads),
			(long long)(tcon->bytes_read));
		seq_printf(m, "\nWrites: %d Bytes: %lld",
			atomic_read(&tcon->num_writes),
			(long long)(tcon->bytes_written));
		seq_printf(m,
			"\nLocks: %d HardLinks: %d Symlinks: %d",
			atomic_read(&tcon->num_locks),
			atomic_read(&tcon->num_hardlinks),
			atomic_read(&tcon->num_symlinks));

		seq_printf(m, "\nOpens: %d Closes: %d Deletes: %d",
			atomic_read(&tcon->num_opens),
			atomic_read(&tcon->num_closes),
			atomic_read(&tcon->num_deletes));
		seq_printf(m, "\nMkdirs: %d Rmdirs: %d",
			atomic_read(&tcon->num_mkdirs),
			atomic_read(&tcon->num_rmdirs));
		seq_printf(m, "\nRenames: %d T2 Renames %d",
			atomic_read(&tcon->num_renames),
			atomic_read(&tcon->num_t2renames));
		seq_printf(m, "\nFindFirst: %d FNext %d FClose %d",
			atomic_read(&tcon->num_ffirst),
			atomic_read(&tcon->num_fnext),
			atomic_read(&tcon->num_fclose));
	}
	read_unlock(&GlobalSMBSeslock);

	seq_putc(m, '\n');
	return 0;
}

static int cifs_stats_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, cifs_stats_proc_show, NULL);
}

static const struct file_operations cifs_stats_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= cifs_stats_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= cifs_stats_proc_write,
};
#endif /* STATS */

static struct proc_dir_entry *proc_fs_cifs;
static const struct file_operations cifsFYI_proc_fops;
static const struct file_operations cifs_oplock_proc_fops;
static const struct file_operations cifs_lookup_cache_proc_fops;
static const struct file_operations traceSMB_proc_fops;
static const struct file_operations cifs_multiuser_mount_proc_fops;
static const struct file_operations cifs_security_flags_proc_fops;
static const struct file_operations cifs_experimental_proc_fops;
static const struct file_operations cifs_linux_ext_proc_fops;

void
cifs_proc_init(void)
{
	proc_fs_cifs = proc_mkdir("fs/cifs", NULL);
	if (proc_fs_cifs == NULL)
		return;

	proc_fs_cifs->owner = THIS_MODULE;
	proc_create("DebugData", 0, proc_fs_cifs, &cifs_debug_data_proc_fops);

#ifdef CONFIG_CIFS_STATS
	proc_create("Stats", 0, proc_fs_cifs, &cifs_stats_proc_fops);
#endif /* STATS */
	proc_create("cifsFYI", 0, proc_fs_cifs, &cifsFYI_proc_fops);
	proc_create("traceSMB", 0, proc_fs_cifs, &traceSMB_proc_fops);
	proc_create("OplockEnabled", 0, proc_fs_cifs, &cifs_oplock_proc_fops);
	proc_create("Experimental", 0, proc_fs_cifs,
		    &cifs_experimental_proc_fops);
	proc_create("LinuxExtensionsEnabled", 0, proc_fs_cifs,
		    &cifs_linux_ext_proc_fops);
	proc_create("MultiuserMount", 0, proc_fs_cifs,
		    &cifs_multiuser_mount_proc_fops);
	proc_create("SecurityFlags", 0, proc_fs_cifs,
		    &cifs_security_flags_proc_fops);
	proc_create("LookupCacheEnabled", 0, proc_fs_cifs,
		    &cifs_lookup_cache_proc_fops);
}

void
cifs_proc_clean(void)
{
	if (proc_fs_cifs == NULL)
		return;

	remove_proc_entry("DebugData", proc_fs_cifs);
	remove_proc_entry("cifsFYI", proc_fs_cifs);
	remove_proc_entry("traceSMB", proc_fs_cifs);
#ifdef CONFIG_CIFS_STATS
	remove_proc_entry("Stats", proc_fs_cifs);
#endif
	remove_proc_entry("MultiuserMount", proc_fs_cifs);
	remove_proc_entry("OplockEnabled", proc_fs_cifs);
	remove_proc_entry("SecurityFlags", proc_fs_cifs);
	remove_proc_entry("LinuxExtensionsEnabled", proc_fs_cifs);
	remove_proc_entry("Experimental", proc_fs_cifs);
	remove_proc_entry("LookupCacheEnabled", proc_fs_cifs);
	remove_proc_entry("fs/cifs", NULL);
}

static int cifsFYI_proc_show(struct seq_file *m, void *v)
{
	seq_printf(m, "%d\n", cifsFYI);
	return 0;
}

static int cifsFYI_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, cifsFYI_proc_show, NULL);
}

static ssize_t cifsFYI_proc_write(struct file *file, const char __user *buffer,
		size_t count, loff_t *ppos)
{
	char c;
	int rc;

	rc = get_user(c, buffer);
	if (rc)
		return rc;
	if (c == '0' || c == 'n' || c == 'N')
		cifsFYI = 0;
	else if (c == '1' || c == 'y' || c == 'Y')
		cifsFYI = 1;
	else if ((c > '1') && (c <= '9'))
		cifsFYI = (int) (c - '0'); /* see cifs_debug.h for meanings */

	return count;
}

static const struct file_operations cifsFYI_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= cifsFYI_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= cifsFYI_proc_write,
};

static int cifs_oplock_proc_show(struct seq_file *m, void *v)
{
	seq_printf(m, "%d\n", oplockEnabled);
	return 0;
}

static int cifs_oplock_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, cifs_oplock_proc_show, NULL);
}

static ssize_t cifs_oplock_proc_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *ppos)
{
	char c;
	int rc;

	rc = get_user(c, buffer);
	if (rc)
		return rc;
	if (c == '0' || c == 'n' || c == 'N')
		oplockEnabled = 0;
	else if (c == '1' || c == 'y' || c == 'Y')
		oplockEnabled = 1;

	return count;
}

static const struct file_operations cifs_oplock_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= cifs_oplock_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= cifs_oplock_proc_write,
};

static int cifs_experimental_proc_show(struct seq_file *m, void *v)
{
	seq_printf(m, "%d\n", experimEnabled);
	return 0;
}

static int cifs_experimental_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, cifs_experimental_proc_show, NULL);
}

static ssize_t cifs_experimental_proc_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *ppos)
{
	char c;
	int rc;

	rc = get_user(c, buffer);
	if (rc)
		return rc;
	if (c == '0' || c == 'n' || c == 'N')
		experimEnabled = 0;
	else if (c == '1' || c == 'y' || c == 'Y')
		experimEnabled = 1;
	else if (c == '2')
		experimEnabled = 2;

	return count;
}

static const struct file_operations cifs_experimental_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= cifs_experimental_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= cifs_experimental_proc_write,
};

static int cifs_linux_ext_proc_show(struct seq_file *m, void *v)
{
	seq_printf(m, "%d\n", linuxExtEnabled);
	return 0;
}

static int cifs_linux_ext_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, cifs_linux_ext_proc_show, NULL);
}

static ssize_t cifs_linux_ext_proc_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *ppos)
{
	char c;
	int rc;

	rc = get_user(c, buffer);
	if (rc)
		return rc;
	if (c == '0' || c == 'n' || c == 'N')
		linuxExtEnabled = 0;
	else if (c == '1' || c == 'y' || c == 'Y')
		linuxExtEnabled = 1;

	return count;
}

static const struct file_operations cifs_linux_ext_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= cifs_linux_ext_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= cifs_linux_ext_proc_write,
};

static int cifs_lookup_cache_proc_show(struct seq_file *m, void *v)
{
	seq_printf(m, "%d\n", lookupCacheEnabled);
	return 0;
}

static int cifs_lookup_cache_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, cifs_lookup_cache_proc_show, NULL);
}

static ssize_t cifs_lookup_cache_proc_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *ppos)
{
	char c;
	int rc;

	rc = get_user(c, buffer);
	if (rc)
		return rc;
	if (c == '0' || c == 'n' || c == 'N')
		lookupCacheEnabled = 0;
	else if (c == '1' || c == 'y' || c == 'Y')
		lookupCacheEnabled = 1;

	return count;
}

static const struct file_operations cifs_lookup_cache_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= cifs_lookup_cache_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= cifs_lookup_cache_proc_write,
};

static int traceSMB_proc_show(struct seq_file *m, void *v)
{
	seq_printf(m, "%d\n", traceSMB);
	return 0;
}

static int traceSMB_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, traceSMB_proc_show, NULL);
}

static ssize_t traceSMB_proc_write(struct file *file, const char __user *buffer,
		size_t count, loff_t *ppos)
{
	char c;
	int rc;

	rc = get_user(c, buffer);
	if (rc)
		return rc;
	if (c == '0' || c == 'n' || c == 'N')
		traceSMB = 0;
	else if (c == '1' || c == 'y' || c == 'Y')
		traceSMB = 1;

	return count;
}

static const struct file_operations traceSMB_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= traceSMB_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= traceSMB_proc_write,
};

static int cifs_multiuser_mount_proc_show(struct seq_file *m, void *v)
{
	seq_printf(m, "%d\n", multiuser_mount);
	return 0;
}

static int cifs_multiuser_mount_proc_open(struct inode *inode, struct file *fh)
{
	return single_open(fh, cifs_multiuser_mount_proc_show, NULL);
}

static ssize_t cifs_multiuser_mount_proc_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *ppos)
{
	char c;
	int rc;

	rc = get_user(c, buffer);
	if (rc)
		return rc;
	if (c == '0' || c == 'n' || c == 'N')
		multiuser_mount = 0;
	else if (c == '1' || c == 'y' || c == 'Y')
		multiuser_mount = 1;

	return count;
}

static const struct file_operations cifs_multiuser_mount_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= cifs_multiuser_mount_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= cifs_multiuser_mount_proc_write,
};

static int cifs_security_flags_proc_show(struct seq_file *m, void *v)
{
	seq_printf(m, "0x%x\n", extended_security);
	return 0;
}

static int cifs_security_flags_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, cifs_security_flags_proc_show, NULL);
}

static ssize_t cifs_security_flags_proc_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *ppos)
{
	unsigned int flags;
	char flags_string[12];
	char c;

	if ((count < 1) || (count > 11))
		return -EINVAL;

	memset(flags_string, 0, 12);

	if (copy_from_user(flags_string, buffer, count))
		return -EFAULT;

	if (count < 3) {
		/* single char or single char followed by null */
		c = flags_string[0];
		if (c == '0' || c == 'n' || c == 'N') {
			extended_security = CIFSSEC_DEF; /* default */
			return count;
		} else if (c == '1' || c == 'y' || c == 'Y') {
			extended_security = CIFSSEC_MAX;
			return count;
		} else if (!isdigit(c)) {
			cERROR(1, ("invalid flag %c", c));
			return -EINVAL;
		}
	}
	/* else we have a number */

	flags = simple_strtoul(flags_string, NULL, 0);

	cFYI(1, ("sec flags 0x%x", flags));

	if (flags <= 0)  {
		cERROR(1, ("invalid security flags %s", flags_string));
		return -EINVAL;
	}

	if (flags & ~CIFSSEC_MASK) {
		cERROR(1, ("attempt to set unsupported security flags 0x%x",
			flags & ~CIFSSEC_MASK));
		return -EINVAL;
	}
	/* flags look ok - update the global security flags for cifs module */
	extended_security = flags;
	if (extended_security & CIFSSEC_MUST_SIGN) {
		/* requiring signing implies signing is allowed */
		extended_security |= CIFSSEC_MAY_SIGN;
		cFYI(1, ("packet signing now required"));
	} else if ((extended_security & CIFSSEC_MAY_SIGN) == 0) {
		cFYI(1, ("packet signing disabled"));
	}
	/* BB should we turn on MAY flags for other MUST options? */
	return count;
}

static const struct file_operations cifs_security_flags_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= cifs_security_flags_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= cifs_security_flags_proc_write,
};
#else
inline void cifs_proc_init(void)
{
}

inline void cifs_proc_clean(void)
{
}
#endif /* PROC_FS */