presto.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

        ENTRY;

        PRESTO_ALLOC(fset, struct presto_file_set *, sizeof(*fset));
        error = -ENOMEM;
        if ( !fset ) {
                printk(KERN_ERR "No memory allocating fset for %s\n", fsetname);
                EXIT;
                return -ENOMEM;
        }
        CDEBUG(D_INODE, "fset at %p\n", fset);

        printk("presto: fsetroot: path %s, fileset name %s\n", path, fsetname);
        error = presto_walk(path, &fset->fset_nd);
        CDEBUG(D_INODE, "\n");
        if (error) {
                EXIT;
                goto out_free;
        }
        dentry = fset->fset_nd.dentry;
        CDEBUG(D_INODE, "\n");

        error = -ENXIO;
        if ( !presto_ispresto(dentry->d_inode) ) {
                EXIT;
                goto out_dput;
        }

        CDEBUG(D_INODE, "\n");
        cache = presto_get_cache(dentry->d_inode);
        if (!cache) {
                printk(KERN_ERR "No cache found for %s\n", path);
                EXIT;
                goto out_dput;
        }

        CDEBUG(D_INODE, "\n");
        error = -EINVAL;
        if ( !cache->cache_mtpt) {
                printk(KERN_ERR "Presto - no mountpoint: fsetroot fails!\n");
                EXIT;
                goto out_dput;
        }
        CDEBUG(D_INODE, "\n");

        if (!cache->cache_root_fileset)  {
                printk(KERN_ERR "Presto - no file set: fsetroot fails!\n");
                EXIT;
                goto out_dput;
        }

        error = -EEXIST;
        CDEBUG(D_INODE, "\n");
        fset2 = presto_fset(dentry);
        if (fset2 && (fset2->fset_mtpt == dentry) ) { 
                printk(KERN_ERR "Fsetroot already set (path %s)\n", path);
                EXIT;
                goto out_dput;
        }

        fset->fset_cache = cache;
        fset->fset_mtpt = dentry;
        fset->fset_name = fsetname;
        fset->fset_chunkbits = CHUNK_BITS;
        fset->fset_flags = flags;
	fset->fset_file_maxio = FSET_DEFAULT_MAX_FILEIO; 

        dentry->d_fsdata = (void *) ( ((long)fset) + PRESTO_FSETROOT );
        list_add(&fset->fset_list, &cache->cache_fset_list);

        error = presto_init_kml_file(fset);
        if ( error ) {
                EXIT;
                CDEBUG(D_JOURNAL, "Error init_kml %d\n", error);
                goto out_list_del;
        }

        error = presto_init_last_rcvd_file(fset);
        if ( error ) {
                int rc;
                EXIT;
                rc = presto_close_journal_file(fset);
                CDEBUG(D_JOURNAL, "Error init_lastrcvd %d, cleanup %d\n", error, rc);
                goto out_list_del;
        }

        error = presto_init_lml_file(fset);
        if ( error ) {
                int rc;
                EXIT;
                rc = presto_close_journal_file(fset);
                CDEBUG(D_JOURNAL, "Error init_lml %d, cleanup %d\n", error, rc);
                goto out_list_del;
        }

#ifdef  CONFIG_KREINT
        /* initialize kml reint buffer */
        error = kml_init (fset); 
        if ( error ) {
                int rc;
                EXIT;
                rc = presto_close_journal_file(fset);
                CDEBUG(D_JOURNAL, "Error init kml reint %d, cleanup %d\n", 
                                error, rc);
                goto out_list_del;
        }
#endif
        if ( dentry->d_inode == dentry->d_inode->i_sb->s_root->d_inode) {
                cache->cache_flags |= CACHE_FSETROOT_SET;
        }

        CDEBUG(D_PIOCTL, "-------> fset at %p, dentry at %p, mtpt %p, fset %s, cache %p, d_fsdata %p\n",
               fset, dentry, fset->fset_mtpt, fset->fset_name, cache, dentry->d_fsdata);

        EXIT;
        return 0;

 out_list_del:
        list_del(&fset->fset_list);
        dentry->d_fsdata = 0;
 out_dput:
        path_release(&fset->fset_nd); 
 out_free:
        PRESTO_FREE(fset, sizeof(*fset));
        return error;
}

int presto_get_kmlsize(char *path, size_t *size)
{
        struct nameidata nd;
        struct presto_file_set *fset;
        struct dentry *dentry;
        int error;

        ENTRY;
        error = presto_walk(path, &nd);
        if (error) {
                EXIT;
                return error;
        }
        dentry = nd.dentry;

        error = -ENXIO;
        if ( !presto_ispresto(dentry->d_inode) ) {
                EXIT;
                goto kml_out;
        }

        error = -EINVAL;
        if ( ! presto_dentry_is_fsetroot(dentry)) {
                EXIT;
                goto kml_out;
        }

        fset = presto_dentry2fset(dentry);
        if (!fset) {
                EXIT;
                goto kml_out;
        }
        error = 0;
        *size = fset->fset_kml.fd_offset;

 kml_out:
        path_release(&nd);
        return error;
}

int presto_clear_fsetroot(char *path)
{
        struct nameidata nd;
        struct presto_file_set *fset;
        struct dentry *dentry;
        struct presto_cache *cache;
        int error;

        ENTRY;
        error = presto_walk(path, &nd);
        if (error) {
                EXIT;
                return error;
        }
        dentry = nd.dentry;

        error = -ENXIO;
        if ( !presto_ispresto(dentry->d_inode) ) {
                EXIT;
                goto put_out;
        }

        error = -EINVAL;
        if ( ! presto_dentry_is_fsetroot(dentry)) {
                EXIT;
                goto put_out;
        }

        fset = presto_dentry2fset(dentry);
        if (!fset) {
                EXIT;
                goto put_out;
        }

#ifdef  CONFIG_KREINT
        error = kml_cleanup (fset);
        if ( error ) {
                printk("InterMezzo: Closing kml for fset %s: %d\n",
                       fset->fset_name, error);
        }
#endif

        error = presto_close_journal_file(fset);
        if ( error ) {
                printk("InterMezzo: Closing journal for fset %s: %d\n",
                       fset->fset_name, error);
        }
        cache = fset->fset_cache;
        cache->cache_flags &= ~CACHE_FSETROOT_SET;

        list_del(&fset->fset_list);
        dentry->d_fsdata = 0;
        path_release(&fset->fset_nd);
        fset->fset_mtpt = NULL;
        PRESTO_FREE(fset->fset_name, strlen(fset->fset_name) + 1);
        PRESTO_FREE(fset, sizeof(*fset));
        EXIT;

put_out:
        path_release(&nd); /* for our lookup */
        return error;
}

int presto_clear_all_fsetroots(char *path)
{
        struct nameidata nd;
        struct presto_file_set *fset;
        struct dentry *dentry;
        struct presto_cache *cache;
        int error;
        struct list_head *tmp,*tmpnext;


        ENTRY;
        error = presto_walk(path, &nd);
        if (error) {
                EXIT;
                return error;
        }
        dentry = nd.dentry;

        error = -ENXIO;
        if ( !presto_ispresto(dentry->d_inode) ) {
                EXIT;
                goto put_out;
        }

        error = -EINVAL;
        if ( ! presto_dentry_is_fsetroot(dentry)) {
                EXIT;
                goto put_out;
        }

        fset = presto_dentry2fset(dentry);
        if (!fset) {
                EXIT;
                goto put_out;
        }

        cache = fset->fset_cache;
        cache = fset->fset_cache;
        cache->cache_flags &= ~CACHE_FSETROOT_SET;

        tmp = &cache->cache_fset_list;
        tmpnext = tmp->next;
        while ( tmpnext != &cache->cache_fset_list) {
		tmp=tmpnext;
                tmpnext=tmp->next;
                fset = list_entry(tmp, struct presto_file_set, fset_list);

                
                error = presto_close_journal_file(fset);
                if ( error ) {
                        printk("InterMezzo: Closing journal for fset %s: %d\n",
                               fset->fset_name, error);
                }
                list_del(&fset->fset_list);
                fset->fset_mtpt->d_fsdata = 0;
                path_release(&fset->fset_nd);
                fset->fset_mtpt = NULL;
                PRESTO_FREE(fset->fset_name, strlen(fset->fset_name) +1);
                PRESTO_FREE(fset, sizeof(*fset));
        }

        EXIT;
 put_out:
        path_release(&nd); /* for our lookup */
        return error;
}


int presto_get_lastrecno(char *path, off_t *recno)
{
        struct nameidata nd; 
        struct presto_file_set *fset;
        struct dentry *dentry;
        int error;
        ENTRY;

        error = presto_walk(path, &nd);
        if (error) {
                EXIT;
                return error;
        }

        dentry = nd.dentry;

        error = -ENXIO;
        if ( !presto_ispresto(dentry->d_inode) ) {
                EXIT;
                goto kml_out;
        }

        error = -EINVAL;
        if ( ! presto_dentry_is_fsetroot(dentry)) {
                EXIT;
                goto kml_out;
        }

        fset = presto_dentry2fset(dentry);
        if (!fset) {
                EXIT;
                goto kml_out;
        }
        error = 0;
        *recno = fset->fset_kml.fd_recno;

 kml_out:
        path_release(&nd);
        return error;
}

/* 
   if *cookie != 0, lento must wait for this cookie
   before releasing the permit, operations are in progress. 
*/ 
int presto_permit_downcall( const char * path, int *cookie )
{
        int result;
        struct presto_file_set *fset; 

        fset = presto_path2fileset(path);
        if (IS_ERR(fset)) { 
                EXIT;
                return PTR_ERR(fset);
        }

	lock_kernel();
        if (fset->fset_permit_count != 0) {
                /* is there are previous cookie? */
                if (fset->fset_permit_cookie == 0) {
                        CDEBUG(D_CACHE, "presto installing cookie 0x%x, %s\n",
                               *cookie, path);
                        fset->fset_permit_cookie = *cookie;
                } else {
                        *cookie = fset->fset_permit_cookie;
                        CDEBUG(D_CACHE, "presto has cookie 0x%x, %s\n",
                               *cookie, path);
                }
                result = presto_mark_fset(path, 0, FSET_PERMIT_WAITING, NULL);
        } else {
                *cookie = 0;
                CDEBUG(D_CACHE, "presto releasing permit %s\n", path);
                result = presto_mark_fset(path, ~FSET_HASPERMIT, 0, NULL);
        }
	unlock_kernel();

        return result;
}

inline int presto_is_read_only(struct presto_file_set * fset)
{
        int minor, mask;
        struct presto_cache *cache = fset->fset_cache;

        minor= cache->cache_psdev->uc_minor;
        mask= (ISLENTO(minor)? FSET_LENTO_RO : FSET_CLIENT_RO);
        if ( fset->fset_flags & mask )
                return 1;
        mask= (ISLENTO(minor)? CACHE_LENTO_RO : CACHE_CLIENT_RO);
        return  ((cache->cache_flags & mask)? 1 : 0);
}