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/*

 * High-level vfs implementation.

 *

 * Copyright (C) 2008 Bahadir Balban

 */

#include <fs.h>

#include <vfs.h>

#include <task.h>

#include <path.h>

LINK_DECLARE(vnode_cache);

LINK_DECLARE(dentry_cache);

struct vfs_mountpoint vfs_root;

struct id_pool *vfs_fsidx_pool;

/*

 * Vnodes in the vnode cache have 2 keys. One is their dentry names, the other

 * is their vnum. This one checks the vnode cache by the given vnum first.

 * If nothing is found, it reads the vnode from disk into cache. This is called

 * by system calls since tasks keep an fd-to-vnum table.

 */

struct vnode *vfs_vnode_lookup_byvnum(struct superblock *sb, unsigned long vnum)

{

        struct vnode *v;

        int err;

        /* Check the vnode flat list by vnum */

        list_foreach_struct(v, &vnode_cache, cache_list)

                if (v->vnum == vnum)

                        return v;

        /* Check the actual filesystem for the vnode */

        v = vfs_alloc_vnode();

        v->vnum = vnum;

        /* Note this only checks given superblock */

        if ((err = sb->ops->read_vnode(sb, v)) < 0) {

                vfs_free_vnode(v);

                return PTR_ERR(err);

        }

        /* Add the vnode back to vnode flat list */

        list_insert(&v->cache_list, &vnode_cache);

        return v;

}

/*

 * Vnodes in the vnode cache have 2 keys. One is the set of dentry names they

 * have, the other is their vnum. This one checks the vnode cache by the path

 * first. If nothing is found, it reads the vnode from disk into the cache.

 */

struct vnode *vfs_vnode_lookup_bypath(struct pathdata *pdata)

{

        const char *firstcomp;

        /*

         * This does vfs cache + fs lookup.

         */

        BUG_ON(list_empty(&pdata->list));

        firstcomp = pathdata_next_component(pdata);

        return pdata->vstart->ops.lookup(pdata->vstart, pdata, firstcomp);

}

int vfs_mount_root(struct superblock *sb)

{

        /*

         * Lookup the root vnode of this superblock.

         * The root superblock has vnode number 0.

         */

        vfs_root.pivot = vfs_vnode_lookup_byvnum(sb, sb->fsidx | 0);

        vfs_root.sb = sb;

        return 0;

}