inode.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

/*
 *  inode.c
 *
 *  Copyright (C) 1995, 1996 by Paal-Kr. Engstad and Volker Lendecke
 *  Copyright (C) 1997 by Volker Lendecke
 *
 *  Please add a note about your changes to smbfs in the ChangeLog file.
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/locks.h>
#include <linux/malloc.h>
#include <linux/init.h>
#include <linux/file.h>
#include <linux/dcache.h>
#include <linux/smp_lock.h>
#include <linux/nls.h>

#include <linux/smb_fs.h>
#include <linux/smbno.h>
#include <linux/smb_mount.h>

#include <asm/system.h>
#include <asm/uaccess.h>

#include "smb_debug.h"
#include "getopt.h"

/* Always pick a default string */
#ifdef CONFIG_SMB_NLS_REMOTE
#define SMB_NLS_REMOTE CONFIG_SMB_NLS_REMOTE
#else
#define SMB_NLS_REMOTE ""
#endif

static void smb_delete_inode(struct inode *);
static void smb_put_super(struct super_block *);
static int  smb_statfs(struct super_block *, struct statfs *);
static void smb_set_inode_attr(struct inode *, struct smb_fattr *);

static struct super_operations smb_sops =
{
	put_inode:	force_delete,
	delete_inode:	smb_delete_inode,
	put_super:	smb_put_super,
	statfs:		smb_statfs,
};


/* We are always generating a new inode here */
struct inode *
smb_iget(struct super_block *sb, struct smb_fattr *fattr)
{
	struct inode *result;

	DEBUG1("smb_iget: %p\n", fattr);

	result = new_inode(sb);
	if (!result)
		return result;
	result->i_ino = fattr->f_ino;
	memset(&(result->u.smbfs_i), 0, sizeof(result->u.smbfs_i));
	smb_set_inode_attr(result, fattr);
	if (S_ISREG(result->i_mode)) {
		result->i_op = &smb_file_inode_operations;
		result->i_fop = &smb_file_operations;
		result->i_data.a_ops = &smb_file_aops;
	} else if (S_ISDIR(result->i_mode)) {
		result->i_op = &smb_dir_inode_operations;
		result->i_fop = &smb_dir_operations;
	}
	insert_inode_hash(result);
	return result;
}

/*
 * Copy the inode data to a smb_fattr structure.
 */
void
smb_get_inode_attr(struct inode *inode, struct smb_fattr *fattr)
{
	memset(fattr, 0, sizeof(struct smb_fattr));
	fattr->f_mode	= inode->i_mode;
	fattr->f_nlink	= inode->i_nlink;
	fattr->f_ino	= inode->i_ino;
	fattr->f_uid	= inode->i_uid;
	fattr->f_gid	= inode->i_gid;
	fattr->f_rdev	= inode->i_rdev;
	fattr->f_size	= inode->i_size;
	fattr->f_mtime	= inode->i_mtime;
	fattr->f_ctime	= inode->i_ctime;
	fattr->f_atime	= inode->i_atime;
	fattr->f_blksize= inode->i_blksize;
	fattr->f_blocks	= inode->i_blocks;

	fattr->attr	= inode->u.smbfs_i.attr;
	/*
	 * Keep the attributes in sync with the inode permissions.
	 */
	if (fattr->f_mode & S_IWUSR)
		fattr->attr &= ~aRONLY;
	else
		fattr->attr |= aRONLY;
}

static void
smb_set_inode_attr(struct inode *inode, struct smb_fattr *fattr)
{
	inode->i_mode	= fattr->f_mode;
	inode->i_nlink	= fattr->f_nlink;
	inode->i_uid	= fattr->f_uid;
	inode->i_gid	= fattr->f_gid;
	inode->i_rdev	= fattr->f_rdev;
	inode->i_ctime	= fattr->f_ctime;
	inode->i_blksize= fattr->f_blksize;
	inode->i_blocks = fattr->f_blocks;
	/*
	 * Don't change the size and mtime/atime fields
	 * if we're writing to the file.
	 */
	if (!(inode->u.smbfs_i.cache_valid & SMB_F_LOCALWRITE))
	{
		inode->i_size  = fattr->f_size;
		inode->i_mtime = fattr->f_mtime;
		inode->i_atime = fattr->f_atime;
	}

	inode->u.smbfs_i.attr = fattr->attr;
	/*
	 * Update the "last time refreshed" field for revalidation.
	 */
	inode->u.smbfs_i.oldmtime = jiffies;
}

/*
 * This is called if the connection has gone bad ...
 * try to kill off all the current inodes.
 */
void
smb_invalidate_inodes(struct smb_sb_info *server)
{
	VERBOSE("\n");
	shrink_dcache_sb(SB_of(server));
	invalidate_inodes(SB_of(server));
}

/*
 * This is called to update the inode attributes after
 * we've made changes to a file or directory.
 */
static int
smb_refresh_inode(struct dentry *dentry)
{
	struct inode *inode = dentry->d_inode;
	int error;
	struct smb_fattr fattr;

	error = smb_proc_getattr(dentry, &fattr);
	if (!error)
	{
		smb_renew_times(dentry);
		/*
		 * Check whether the type part of the mode changed,
		 * and don't update the attributes if it did.
		 */
		if ((inode->i_mode & S_IFMT) == (fattr.f_mode & S_IFMT))
			smb_set_inode_attr(inode, &fattr);
		else
		{
			/*
			 * Big trouble! The inode has become a new object,
			 * so any operations attempted on it are invalid.
			 *
			 * To limit damage, mark the inode as bad so that
			 * subsequent lookup validations will fail.
			 */
			PARANOIA("%s/%s changed mode, %07o to %07o\n",
				 DENTRY_PATH(dentry),
				 inode->i_mode, fattr.f_mode);

			fattr.f_mode = inode->i_mode; /* save mode */
			make_bad_inode(inode);
			inode->i_mode = fattr.f_mode; /* restore mode */
			/*
			 * No need to worry about unhashing the dentry: the
			 * lookup validation will see that the inode is bad.
			 * But we do want to invalidate the caches ...
			 */
			if (!S_ISDIR(inode->i_mode))
				invalidate_inode_pages(inode);
			else
				smb_invalid_dir_cache(inode);
			error = -EIO;
		}
	}
	return error;
}

/*
 * This is called when we want to check whether the inode
 * has changed on the server.  If it has changed, we must
 * invalidate our local caches.
 */
int
smb_revalidate_inode(struct dentry *dentry)
{
	struct inode *inode = dentry->d_inode;
	time_t last_time;
	int error = 0;

	DEBUG1("smb_revalidate_inode\n");
	/*
	 * If this is a file opened with write permissions,
	 * the inode will be up-to-date.
	 */
	lock_kernel();
	if (S_ISREG(inode->i_mode) && smb_is_open(inode))
	{
		if (inode->u.smbfs_i.access != SMB_O_RDONLY)
			goto out;
	}

	/*
	 * Check whether we've recently refreshed the inode.
	 */
	if (time_before(jiffies, inode->u.smbfs_i.oldmtime + HZ/10))
	{
		VERBOSE("up-to-date, jiffies=%lu, oldtime=%lu\n",
			jiffies, inode->u.smbfs_i.oldmtime);
		goto out;
	}

	/*
	 * Save the last modified time, then refresh the inode.
	 * (Note: a size change should have a different mtime.)
	 */
	last_time = inode->i_mtime;
	error = smb_refresh_inode(dentry);
	if (error || inode->i_mtime != last_time)
	{
		VERBOSE("%s/%s changed, old=%ld, new=%ld\n",
			DENTRY_PATH(dentry),
			(long) last_time, (long) inode->i_mtime);

		if (!S_ISDIR(inode->i_mode))
			invalidate_inode_pages(inode);
		else
			smb_invalid_dir_cache(inode);
	}
out:
	unlock_kernel();
	return error;
}

/*
 * This routine is called when i_nlink == 0 and i_count goes to 0.
 * All blocking cleanup operations need to go here to avoid races.
 */
static void
smb_delete_inode(struct inode *ino)
{
	DEBUG1("ino=%ld\n", ino->i_ino);
	lock_kernel();
	if (smb_close(ino))
		PARANOIA("could not close inode %ld\n", ino->i_ino);
	unlock_kernel();
	clear_inode(ino);
}

/* FIXME: flags and has_arg could probably be merged. */
struct option opts[] = {
	{ "version",	1, 0, 'v' },
	{ "win95",	0, SMB_MOUNT_WIN95, 1 },
	{ "oldattr",	0, SMB_MOUNT_OLDATTR, 1 },
	{ "dirattr",	0, SMB_MOUNT_DIRATTR, 1 },
	{ "case",	0, SMB_MOUNT_CASE, 1 },
	{ "uid",	1, 0, 'u' },
	{ "gid",	1, 0, 'g' },
	{ "file_mode",	1, 0, 'f' },
	{ "dir_mode",	1, 0, 'd' },
	{ "iocharset",	1, 0, 'i' },
	{ "codepage",	1, 0, 'c' },
	{ NULL,		0, 0, 0}
};

static int
parse_options(struct smb_mount_data_kernel *mnt, char *options)
{
	int c;
	unsigned long flags;
	unsigned long value;
	char *optarg;
	char *optopt;

	flags = 0;
	while ( (c = smb_getopt("smbfs", &options, opts,
				&optopt, &optarg, &flags, &value)) > 0) {

		VERBOSE("'%s' -> '%s'\n", optopt, optarg ? optarg : "<none>");

		switch (c) {
		case 1:
			/* got a "flag" option */
			break;
		case 'v':
			if (value != SMB_MOUNT_VERSION) {
			printk ("smbfs: Bad mount version %ld, expected %d\n",
				value, SMB_MOUNT_VERSION);
				return 0;
			}
			mnt->version = value;
			break;
		case 'u':
			mnt->uid = value;
			break;
		case 'g':
			mnt->gid = value;
			break;
		case 'f':
			mnt->file_mode = value & (S_IRWXU | S_IRWXG | S_IRWXO);
			mnt->file_mode |= S_IFREG;
			break;
		case 'd':
			mnt->dir_mode = value & (S_IRWXU | S_IRWXG | S_IRWXO);
			mnt->dir_mode |= S_IFDIR;
			break;