/*
* V9FS FID Management
*
+ * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
* Copyright (C) 2005, 2006 by Eric Van Hensbergen <ericvh@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/idr.h>
-#include <asm/semaphore.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "fid.h"
/**
- * v9fs_fid_insert - add a fid to a dentry
+ * v9fs_fid_add - add a fid to a dentry
+ * @dentry: dentry that the fid is being added to
* @fid: fid to add
- * @dentry: dentry that it is being added to
*
*/
struct v9fs_dentry *dent;
P9_DPRINTK(P9_DEBUG_VFS, "fid %d dentry %s\n",
- fid->fid, dentry->d_iname);
+ fid->fid, dentry->d_name.name);
dent = dentry->d_fsdata;
if (!dent) {
}
/**
- * v9fs_fid_lookup - return a locked fid from a dentry
+ * v9fs_fid_find - retrieve a fid that belongs to the specified uid
* @dentry: dentry to look for fid in
- *
- * find a fid in the dentry, obtain its semaphore and return a reference to it.
- * code calling lookup is responsible for releasing lock
- *
- * TODO: only match fids that have the same uid as current user
+ * @uid: return fid that belongs to the specified user
+ * @any: if non-zero, return any fid associated with the dentry
*
*/
-struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
+static struct p9_fid *v9fs_fid_find(struct dentry *dentry, u32 uid, int any)
{
struct v9fs_dentry *dent;
- struct p9_fid *fid;
-
- P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
- dent = dentry->d_fsdata;
- if (dent)
- fid = list_entry(dent->fidlist.next, struct p9_fid, dlist);
- else
- fid = ERR_PTR(-EBADF);
+ struct p9_fid *fid, *ret;
+
+ P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p) uid %d any %d\n",
+ dentry->d_name.name, dentry, uid, any);
+ dent = (struct v9fs_dentry *) dentry->d_fsdata;
+ ret = NULL;
+ if (dent) {
+ spin_lock(&dent->lock);
+ list_for_each_entry(fid, &dent->fidlist, dlist) {
+ if (any || fid->uid == uid) {
+ ret = fid;
+ break;
+ }
+ }
+ spin_unlock(&dent->lock);
+ }
- P9_DPRINTK(P9_DEBUG_VFS, " fid: %p\n", fid);
- return fid;
+ return ret;
}
/**
- * v9fs_fid_clone - lookup the fid for a dentry, clone a private copy and
- * release it
+ * v9fs_fid_lookup - lookup for a fid, try to walk if not found
* @dentry: dentry to look for fid in
*
- * find a fid in the dentry and then clone to a new private fid
- *
- * TODO: only match fids that have the same uid as current user
- *
+ * Look for a fid in the specified dentry for the current user.
+ * If no fid is found, try to create one walking from a fid from the parent
+ * dentry (if it has one), or the root dentry. If the user haven't accessed
+ * the fs yet, attach now and walk from the root.
*/
-struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
+struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
{
- struct p9_fid *ofid, *fid;
+ int i, n, l, clone, any, access;
+ u32 uid;
+ struct p9_fid *fid;
+ struct dentry *d, *ds;
+ struct v9fs_session_info *v9ses;
+ char **wnames, *uname;
+
+ v9ses = v9fs_inode2v9ses(dentry->d_inode);
+ access = v9ses->flags & V9FS_ACCESS_MASK;
+ switch (access) {
+ case V9FS_ACCESS_SINGLE:
+ case V9FS_ACCESS_USER:
+ uid = current->fsuid;
+ any = 0;
+ break;
+
+ case V9FS_ACCESS_ANY:
+ uid = v9ses->uid;
+ any = 1;
+ break;
+
+ default:
+ uid = ~0;
+ any = 0;
+ break;
+ }
- P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
- ofid = v9fs_fid_lookup(dentry);
- if (IS_ERR(ofid))
- return ofid;
+ fid = v9fs_fid_find(dentry, uid, any);
+ if (fid)
+ return fid;
+
+ ds = dentry->d_parent;
+ fid = v9fs_fid_find(ds, uid, any);
+ if (!fid) { /* walk from the root */
+ n = 0;
+ for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
+ n++;
+
+ fid = v9fs_fid_find(ds, uid, any);
+ if (!fid) { /* the user is not attached to the fs yet */
+ if (access == V9FS_ACCESS_SINGLE)
+ return ERR_PTR(-EPERM);
+
+ if (v9fs_extended(v9ses))
+ uname = NULL;
+ else
+ uname = v9ses->uname;
+
+ fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
+ v9ses->aname);
+
+ if (IS_ERR(fid))
+ return fid;
+
+ v9fs_fid_add(ds, fid);
+ }
+ } else /* walk from the parent */
+ n = 1;
+
+ if (ds == dentry)
+ return fid;
+
+ wnames = kmalloc(sizeof(char *) * n, GFP_KERNEL);
+ if (!wnames)
+ return ERR_PTR(-ENOMEM);
+
+ for (d = dentry, i = (n-1); i >= 0; i--, d = d->d_parent)
+ wnames[i] = (char *) d->d_name.name;
+
+ clone = 1;
+ i = 0;
+ while (i < n) {
+ l = min(n - i, P9_MAXWELEM);
+ fid = p9_client_walk(fid, l, &wnames[i], clone);
+ if (IS_ERR(fid)) {
+ kfree(wnames);
+ return fid;
+ }
+
+ i += l;
+ clone = 0;
+ }
- fid = p9_client_walk(ofid, 0, NULL, 1);
+ kfree(wnames);
+ v9fs_fid_add(dentry, fid);
return fid;
}
+
+struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
+{
+ struct p9_fid *fid, *ret;
+
+ fid = v9fs_fid_lookup(dentry);
+ if (IS_ERR(fid))
+ return fid;
+
+ ret = p9_client_walk(fid, 0, NULL, 1);
+ return ret;
+}
projects / linux-2.6-omap-h63xx.git / blobdiff