inode.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

/*
 * Super block/filesystem wide operations
 *
 * Copryright (C) 1996 Peter J. Braam <[e-mail]> and
 * Michael Callahan <[e-mail]>
 *
 * Rewritten for Linux 2.1.  Peter Braam <[e-mail]>
 * Copyright (C) Carnegie Mellon University
 */

#define __NO_VERSION__
#include <linux/module.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/unistd.h>

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

#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/locks.h>
#include <linux/string.h>
#include <asm/uaccess.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <asm/segment.h>

#include <linux/intermezzo_fs.h>
#include <linux/intermezzo_upcall.h>
#include <linux/intermezzo_psdev.h>

extern int presto_remount(struct super_block *, int *, char *);

int presto_excluded_gid = PRESTO_EXCL_GID;

extern int presto_prep(struct dentry *, struct presto_cache **,
                              struct presto_file_set **);
extern void presto_free_cache(struct presto_cache *);


void presto_set_ops(struct inode *inode, struct  filter_fs *filter)
{
	ENTRY; 
        if (!inode || is_bad_inode(inode))
                return;
	if (inode->i_gid == presto_excluded_gid ) { 
		EXIT;
                CDEBUG(D_INODE, "excluded methods for %ld at %p, %p\n",
                       inode->i_ino, inode->i_op, inode->i_fop);
		return; 
	}
        if (S_ISREG(inode->i_mode)) {
                if ( !filter_c2cfiops(filter) ) {
                       filter_setup_file_ops(filter, 
					     inode, &presto_file_iops,
					     &presto_file_fops);
                }
		inode->i_op = filter_c2ufiops(filter);
		inode->i_fop = filter_c2uffops(filter);
                CDEBUG(D_INODE, "set file methods for %ld to %p\n",
                       inode->i_ino, inode->i_op);
        } else if (S_ISDIR(inode->i_mode)) {
		inode->i_op = filter_c2udiops(filter);
		inode->i_fop = filter_c2udfops(filter);
                CDEBUG(D_INODE, "set dir methods for %ld to %p lookup %p\n",
                       inode->i_ino, inode->i_op, inode->i_op->lookup);
        } else if (S_ISLNK(inode->i_mode)) {
                if ( !filter_c2csiops(filter)) {
                        filter_setup_symlink_ops(filter, 
                                                 inode,
                                                 &presto_sym_iops, 
						 &presto_sym_fops);
                }
		inode->i_op = filter_c2usiops(filter);
		inode->i_fop = filter_c2usfops(filter);
                CDEBUG(D_INODE, "set link methods for %ld to %p\n",
                       inode->i_ino, inode->i_op);
        }
	EXIT;
}

void presto_read_inode(struct inode *inode)
{
        struct presto_cache *cache;

        cache = presto_get_cache(inode);
        if ( !cache ) {
                printk("PRESTO: BAD, BAD: cannot find cache\n");
                make_bad_inode(inode);
                return ;
        }

        filter_c2csops(cache->cache_filter)->read_inode(inode);

        CDEBUG(D_INODE, "presto_read_inode: ino %ld, gid %d\n", 
	       inode->i_ino, inode->i_gid);

	//        if (inode->i_gid == presto_excluded_gid)
        //       return;

	presto_set_ops(inode, cache->cache_filter); 
        /* XXX handle special inodes here or not - probably not? */
}

void presto_put_super(struct super_block *sb)
{
        struct presto_cache *cache;
        struct upc_comm *psdev;
        struct super_operations *sops;
        struct list_head *lh;

	ENTRY;
        cache = presto_find_cache(sb->s_dev);
        if (!cache) {
		EXIT;
                goto exit;
	}
        psdev = &upc_comms[presto_c2m(cache)];

        sops = filter_c2csops(cache->cache_filter);
        if (sops->put_super)
                sops->put_super(sb);

        /* free any remaining async upcalls when the filesystem is unmounted */
        lh = psdev->uc_pending.next;
        while ( lh != &psdev->uc_pending) {
                struct upc_req *req;
                req = list_entry(lh, struct upc_req, rq_chain);

                /* assignment must be here: we are about to free &lh */
                lh = lh->next;
                if ( ! (req->rq_flags & REQ_ASYNC) ) 
                        continue;
                list_del(&(req->rq_chain));
                PRESTO_FREE(req->rq_data, req->rq_bufsize);
                PRESTO_FREE(req, sizeof(struct upc_req));
        }

        presto_free_cache(cache);

exit:
        CDEBUG(D_MALLOC, "after umount: kmem %ld, vmem %ld\n",
               presto_kmemory, presto_vmemory);
        MOD_DEC_USE_COUNT;
        return ;
}


/* symlinks can be chowned */
struct inode_operations presto_sym_iops = {
	setattr:	presto_setattr
};

/* NULL for now */
struct file_operations presto_sym_fops; 

struct super_operations presto_super_ops = {
        read_inode:     presto_read_inode,
        put_super:      presto_put_super,
        remount_fs:     presto_remount
};
MODULE_LICENSE("GPL");