---

yaml
---
r: 71061
b: refs/heads/master
c: ba17674
h: refs/heads/master
i:
  71059: 307b19d
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bd32b82df9876af439f1760a599c0e2da9198bda
+refs/heads/master: ba17674fe02909fef049fd4b620a2805bdb8c693

trunk/Documentation/filesystems/9p.txt

@@ -88,6 +88,16 @@ OPTIONS
   		This can be used to share devices/named pipes/sockets between
 		hosts.  This functionality will be expanded in later versions.
 
+  access	there are three access modes.
+			user  = if a user tries to access a file on v9fs
+			        filesystem for the first time, v9fs sends an
+			        attach command (Tattach) for that user.
+				This is the default mode.
+			<uid> = allows only user with uid=<uid> to access
+				the files on the mounted filesystem
+			any   = v9fs does single attach and performs all
+				operations as one user
+
 RESOURCES
 =========
 

trunk/fs/9p/fid.c

@@ -1,6 +1,7 @@
 /*
  * 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
@@ -34,9 +35,9 @@
 #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
  *
  */
 
@@ -66,52 +67,144 @@ int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
 }
 
 /**
- * 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_iname, 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; 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 (!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;
+}

trunk/fs/9p/v9fs.c

@@ -91,6 +91,8 @@ enum {
 	Opt_legacy, Opt_nodevmap,
 	/* Cache options */
 	Opt_cache_loose,
+	/* Access options */
+	Opt_access,
 	/* Error token */
 	Opt_err
 };
@@ -108,6 +110,7 @@ static match_table_t tokens = {
 	{Opt_nodevmap, "nodevmap"},
 	{Opt_cache_loose, "cache=loose"},
 	{Opt_cache_loose, "loose"},
+	{Opt_access, "access=%s"},
 	{Opt_err, NULL}
 };
 
@@ -125,10 +128,10 @@ static void v9fs_parse_options(struct v9fs_session_info *v9ses)
 	char *p;
 	int option;
 	int ret;
+	char *s, *e;
 
 	/* setup defaults */
 	v9ses->maxdata = 8192;
-	v9ses->flags = V9FS_EXTENDED;
 	v9ses->afid = ~0;
 	v9ses->debug = 0;
 	v9ses->cache = 0;
@@ -172,10 +175,10 @@ static void v9fs_parse_options(struct v9fs_session_info *v9ses)
 			v9ses->trans = v9fs_match_trans(&args[0]);
 			break;
 		case Opt_uname:
-			match_strcpy(v9ses->name, &args[0]);
+			match_strcpy(v9ses->uname, &args[0]);
 			break;
 		case Opt_remotename:
-			match_strcpy(v9ses->remotename, &args[0]);
+			match_strcpy(v9ses->aname, &args[0]);
 			break;
 		case Opt_legacy:
 			v9ses->flags &= ~V9FS_EXTENDED;
@@ -186,6 +189,22 @@ static void v9fs_parse_options(struct v9fs_session_info *v9ses)
 		case Opt_cache_loose:
 			v9ses->cache = CACHE_LOOSE;
 			break;
+
+		case Opt_access:
+			s = match_strdup(&args[0]);
+			v9ses->flags &= ~V9FS_ACCESS_MASK;
+			if (strcmp(s, "user") == 0)
+				v9ses->flags |= V9FS_ACCESS_USER;
+			else if (strcmp(s, "any") == 0)
+				v9ses->flags |= V9FS_ACCESS_ANY;
+			else {
+				v9ses->flags |= V9FS_ACCESS_SINGLE;
+				v9ses->uid = simple_strtol(s, &e, 10);
+				if (*e != '\0')
+					v9ses->uid = ~0;
+			}
+			break;
+
 		default:
 			continue;
 		}
@@ -207,21 +226,22 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	struct p9_trans *trans = NULL;
 	struct p9_fid *fid;
 
-	v9ses->name = __getname();
-	if (!v9ses->name)
+	v9ses->uname = __getname();
+	if (!v9ses->uname)
 		return ERR_PTR(-ENOMEM);
 
-	v9ses->remotename = __getname();
-	if (!v9ses->remotename) {
-		__putname(v9ses->name);
+	v9ses->aname = __getname();
+	if (!v9ses->aname) {
+		__putname(v9ses->uname);
 		return ERR_PTR(-ENOMEM);
 	}
 
-	strcpy(v9ses->name, V9FS_DEFUSER);
-	strcpy(v9ses->remotename, V9FS_DEFANAME);
+	v9ses->flags = V9FS_EXTENDED | V9FS_ACCESS_USER;
+	strcpy(v9ses->uname, V9FS_DEFUSER);
+	strcpy(v9ses->aname, V9FS_DEFANAME);
+	v9ses->uid = ~0;
 	v9ses->dfltuid = V9FS_DEFUID;
 	v9ses->dfltgid = V9FS_DEFGID;
-
 	v9ses->options = kstrdup(data, GFP_KERNEL);
 	v9fs_parse_options(v9ses);
 
@@ -255,15 +275,32 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 		goto error;
 	}
 
-	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->name,
-							v9ses->remotename);
+	if (!v9ses->clnt->dotu)
+		v9ses->flags &= ~V9FS_EXTENDED;
+
+	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
+	if (!v9fs_extended(v9ses) &&
+		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
+
+		v9ses->flags &= ~V9FS_ACCESS_MASK;
+		v9ses->flags |= V9FS_ACCESS_ANY;
+		v9ses->uid = ~0;
+	}
+
+	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
+							v9ses->aname);
 	if (IS_ERR(fid)) {
 		retval = PTR_ERR(fid);
 		fid = NULL;
 		P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
 		goto error;
 	}
 
+	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
+		fid->uid = v9ses->uid;
+	else
+		fid->uid = ~0;
+
 	return fid;
 
 error:
@@ -284,8 +321,8 @@ void v9fs_session_close(struct v9fs_session_info *v9ses)
 		v9ses->clnt = NULL;
 	}
 
-	__putname(v9ses->name);
-	__putname(v9ses->remotename);
+	__putname(v9ses->uname);
+	__putname(v9ses->aname);
 	kfree(v9ses->options);
 }
 

trunk/fs/9p/v9fs.h

@@ -36,18 +36,23 @@ struct v9fs_session_info {
 	unsigned int cache;	/* cache mode */
 
 	char *options;		/* copy of mount options */
-	char *name;		/* user name to mount as */
-	char *remotename;	/* name of remote hierarchy being mounted */
+	char *uname;		/* user name to mount as */
+	char *aname;		/* name of remote hierarchy being mounted */
 	unsigned int dfltuid;	/* default uid/muid for legacy support */
 	unsigned int dfltgid;	/* default gid for legacy support */
+	u32 uid;		/* if ACCESS_SINGLE, the uid that has access */
 	struct p9_trans_module *trans; /* 9p transport */
 	struct p9_client *clnt;	/* 9p client */
 	struct dentry *debugfs_dir;
 };
 
 /* session flags */
 enum {
-	V9FS_EXTENDED,
+	V9FS_EXTENDED		= 0x01,	/* 9P2000.u */
+	V9FS_ACCESS_MASK	= 0x06,	/* access mask */
+	V9FS_ACCESS_SINGLE	= 0x02,	/* only one user can access the files */
+	V9FS_ACCESS_USER	= 0x04,	/* attache per user */
+	V9FS_ACCESS_ANY		= 0x06,	/* use the same attach for all users */
 };
 
 /* possible values of ->cache */