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Implemented vfs_lookup_byvnum() close to what it should look like.

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This commit is contained in:
Bahadir Balban
2008-02-14 15:46:30 +00:00
parent d3b6817887
commit 1b387a1704
4 changed files with 43 additions and 19 deletions
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34
tasks/fs0/src/vfs.c
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@@ -12,29 +12,45 @@ struct list_head dentry_cache;
/*
* 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.
* 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_lookup_byvnum(struct superblock *sb, unsigned long vnum)
{
struct vnode *v;
int err;
/* Check the vnode cache by vnum */
list_for_each_entry(v, vnode_cache, cache_list)
if (v->vnum == vnum)
return v;
/* Otherwise ask the filesystem:
* TODO:
* vfs_alloc_vnode() -> This should also add the empty vnode to vnode cache.
* read_vnode() -> read it from filesystem.
* return what's read.
/*
* In the future it will be possible that a vnum known by the fd table
* is not in the cache, because the cache will be able to grow and shrink.
* But currently it just grows, so its a bug that a known vnum is not in
* the cache.
*/
BUG();
/* Check the actual filesystem for the vnode */
v = vfs_alloc_vnode();
v->vnum = vnum;
if ((err = v->read_vnode(sb, v)) < 0) {
vfs_free_vnode(v);
return err;
}
/* Add the vnode back to vnode cache */
list_add(&v->cache_list, &vnode_cache);
return v;
}
/*
* Vnodes in the vnode cache have 2 keys. One is their dentry name, 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.
* 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_lookup_bypath(struct superblock *sb, char *path)
{