Merge tag '9p-for-5.20' of https://github.com/martinetd/linux

Pull 9p updates from Dominique Martinet:

 - a couple of fixes

 - add a tracepoint for fid refcounting

 - some cleanup/followup on fid lookup

 - some cleanup around req refcounting

* tag '9p-for-5.20' of https://github.com/martinetd/linux:
  net/9p: Initialize the iounit field during fid creation
  net: 9p: fix refcount leak in p9_read_work() error handling
  9p: roll p9_tag_remove into p9_req_put
  9p: Add client parameter to p9_req_put()
  9p: Drop kref usage
  9p: Fix some kernel-doc comments
  9p fid refcount: cleanup p9_fid_put calls
  9p fid refcount: add a 9p_fid_ref tracepoint
  9p fid refcount: add p9_fid_get/put wrappers
  9p: Fix minor typo in code comment
  9p: Remove unnecessary variable for old fids while walking from d_parent
  9p: Make the path walk logic more clear about when cloning is required
  9p: Track the root fid with its own variable during lookups

Author: torvalds

fs/9p/fid.c

@@ -28,14 +28,18 @@ static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid)
 /**
  * v9fs_fid_add - add a fid to a dentry
  * @dentry: dentry that the fid is being added to
- * @fid: fid to add
+ * @pfid: fid to add, NULLed out
  *
  */
-void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
+void v9fs_fid_add(struct dentry *dentry, struct p9_fid **pfid)
 {
+	struct p9_fid *fid = *pfid;
+
 	spin_lock(&dentry->d_lock);
 	__add_fid(dentry, fid);
 	spin_unlock(&dentry->d_lock);
+
+	*pfid = NULL;
 }
 
 /**
@@ -56,7 +60,7 @@ static struct p9_fid *v9fs_fid_find_inode(struct inode *inode, kuid_t uid)
 	h = (struct hlist_head *)&inode->i_private;
 	hlist_for_each_entry(fid, h, ilist) {
 		if (uid_eq(fid->uid, uid)) {
-			refcount_inc(&fid->count);
+			p9_fid_get(fid);
 			ret = fid;
 			break;
 		}
@@ -68,15 +72,19 @@ static struct p9_fid *v9fs_fid_find_inode(struct inode *inode, kuid_t uid)
 /**
  * v9fs_open_fid_add - add an open fid to an inode
  * @inode: inode that the fid is being added to
- * @fid: fid to add
+ * @pfid: fid to add, NULLed out
  *
  */
 
-void v9fs_open_fid_add(struct inode *inode, struct p9_fid *fid)
+void v9fs_open_fid_add(struct inode *inode, struct p9_fid **pfid)
 {
+	struct p9_fid *fid = *pfid;
+
 	spin_lock(&inode->i_lock);
 	hlist_add_head(&fid->ilist, (struct hlist_head *)&inode->i_private);
 	spin_unlock(&inode->i_lock);
+
+	*pfid = NULL;
 }
 
 
@@ -104,7 +112,7 @@ static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
 		hlist_for_each_entry(fid, h, dlist) {
 			if (any || uid_eq(fid->uid, uid)) {
 				ret = fid;
-				refcount_inc(&ret->count);
+				p9_fid_get(ret);
 				break;
 			}
 		}
@@ -150,9 +158,9 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
 {
 	struct dentry *ds;
 	const unsigned char **wnames, *uname;
-	int i, n, l, clone, access;
+	int i, n, l, access;
 	struct v9fs_session_info *v9ses;
-	struct p9_fid *fid, *old_fid;
+	struct p9_fid *fid, *root_fid, *old_fid;
 
 	v9ses = v9fs_dentry2v9ses(dentry);
 	access = v9ses->flags & V9FS_ACCESS_MASK;
@@ -169,17 +177,17 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
 	fid = v9fs_fid_find(ds, uid, any);
 	if (fid) {
 		/* Found the parent fid do a lookup with that */
-		struct p9_fid *ofid = fid;
+		old_fid = fid;
 
-		fid = p9_client_walk(ofid, 1, &dentry->d_name.name, 1);
-		p9_client_clunk(ofid);
+		fid = p9_client_walk(old_fid, 1, &dentry->d_name.name, 1);
+		p9_fid_put(old_fid);
 		goto fid_out;
 	}
 	up_read(&v9ses->rename_sem);
 
 	/* start from the root and try to do a lookup */
-	fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
-	if (!fid) {
+	root_fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
+	if (!root_fid) {
 		/* the user is not attached to the fs yet */
 		if (access == V9FS_ACCESS_SINGLE)
 			return ERR_PTR(-EPERM);
@@ -194,12 +202,13 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
 		if (IS_ERR(fid))
 			return fid;
 
-		refcount_inc(&fid->count);
-		v9fs_fid_add(dentry->d_sb->s_root, fid);
+		root_fid = p9_fid_get(fid);
+		v9fs_fid_add(dentry->d_sb->s_root, &fid);
 	}
 	/* If we are root ourself just return that */
 	if (dentry->d_sb->s_root == dentry)
-		return fid;
+		return root_fid;
+
 	/*
 	 * Do a multipath walk with attached root.
 	 * When walking parent we need to make sure we
@@ -211,39 +220,39 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
 		fid = ERR_PTR(n);
 		goto err_out;
 	}
-	old_fid = fid;
-	clone = 1;
+	fid = root_fid;
+	old_fid = root_fid;
 	i = 0;
 	while (i < n) {
 		l = min(n - i, P9_MAXWELEM);
 		/*
 		 * We need to hold rename lock when doing a multipath
-		 * walk to ensure none of the patch component change
+		 * walk to ensure none of the path components change
 		 */
-		fid = p9_client_walk(fid, l, &wnames[i], clone);
+		fid = p9_client_walk(old_fid, l, &wnames[i],
+				     old_fid == root_fid /* clone */);
 		/* non-cloning walk will return the same fid */
 		if (fid != old_fid) {
-			p9_client_clunk(old_fid);
+			p9_fid_put(old_fid);
 			old_fid = fid;
 		}
 		if (IS_ERR(fid)) {
 			kfree(wnames);
 			goto err_out;
 		}
 		i += l;
-		clone = 0;
 	}
 	kfree(wnames);
 fid_out:
 	if (!IS_ERR(fid)) {
 		spin_lock(&dentry->d_lock);
 		if (d_unhashed(dentry)) {
 			spin_unlock(&dentry->d_lock);
-			p9_client_clunk(fid);
+			p9_fid_put(fid);
 			fid = ERR_PTR(-ENOENT);
 		} else {
 			__add_fid(dentry, fid);
-			refcount_inc(&fid->count);
+			p9_fid_get(fid);
 			spin_unlock(&dentry->d_lock);
 		}
 	}
@@ -300,7 +309,7 @@ struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
 	fid = clone_fid(ofid);
 	if (IS_ERR(fid))
 		goto error_out;
-	p9_client_clunk(ofid);
+	p9_fid_put(ofid);
 	/*
 	 * writeback fid will only be used to write back the
 	 * dirty pages. We always request for the open fid in read-write
@@ -309,7 +318,7 @@ struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
 	 */
 	err = p9_client_open(fid, O_RDWR);
 	if (err < 0) {
-		p9_client_clunk(fid);
+		p9_fid_put(fid);
 		fid = ERR_PTR(err);
 		goto error_out;
 	}

fs/9p/fid.h

@@ -13,9 +13,9 @@ static inline struct p9_fid *v9fs_parent_fid(struct dentry *dentry)
 {
 	return v9fs_fid_lookup(dentry->d_parent);
 }
-void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid);
+void v9fs_fid_add(struct dentry *dentry, struct p9_fid **fid);
 struct p9_fid *v9fs_writeback_fid(struct dentry *dentry);
-void v9fs_open_fid_add(struct inode *inode, struct p9_fid *fid);
+void v9fs_open_fid_add(struct inode *inode, struct p9_fid **fid);
 static inline struct p9_fid *clone_fid(struct p9_fid *fid)
 {
 	return IS_ERR(fid) ? fid :  p9_client_walk(fid, 0, NULL, 1);
@@ -29,7 +29,7 @@ static inline struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
 		return fid;
 
 	nfid = clone_fid(fid);
-	p9_client_clunk(fid);
+	p9_fid_put(fid);
 	return nfid;
 }
 #endif

fs/9p/vfs_addr.c

@@ -73,7 +73,7 @@ static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
 		BUG_ON(!fid);
 	}
 
-	refcount_inc(&fid->count);
+	p9_fid_get(fid);
 	rreq->netfs_priv = fid;
 	return 0;
 }
@@ -86,7 +86,7 @@ static void v9fs_free_request(struct netfs_io_request *rreq)
 {
 	struct p9_fid *fid = rreq->netfs_priv;
 
-	p9_client_clunk(fid);
+	p9_fid_put(fid);
 }
 
 /**

fs/9p/vfs_dentry.c

@@ -54,7 +54,7 @@ static void v9fs_dentry_release(struct dentry *dentry)
 	p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
 		 dentry, dentry);
 	hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
-		p9_client_clunk(hlist_entry(p, struct p9_fid, dlist));
+		p9_fid_put(hlist_entry(p, struct p9_fid, dlist));
 	dentry->d_fsdata = NULL;
 }
 
@@ -85,7 +85,7 @@ static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
 			retval = v9fs_refresh_inode_dotl(fid, inode);
 		else
 			retval = v9fs_refresh_inode(fid, inode);
-		p9_client_clunk(fid);
+		p9_fid_put(fid);
 
 		if (retval == -ENOENT)
 			return 0;

fs/9p/vfs_dir.c

@@ -218,7 +218,7 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 		spin_lock(&inode->i_lock);
 		hlist_del(&fid->ilist);
 		spin_unlock(&inode->i_lock);
-		p9_client_clunk(fid);
+		p9_fid_put(fid);
 	}
 
 	if ((filp->f_mode & FMODE_WRITE)) {

fs/9p/vfs_file.c

@@ -63,15 +63,16 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 
 		err = p9_client_open(fid, omode);
 		if (err < 0) {
-			p9_client_clunk(fid);
+			p9_fid_put(fid);
 			return err;
 		}
 		if ((file->f_flags & O_APPEND) &&
 			(!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
 			generic_file_llseek(file, 0, SEEK_END);
+
+		file->private_data = fid;
 	}
 
-	file->private_data = fid;
 	mutex_lock(&v9inode->v_mutex);
 	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
 	    !v9inode->writeback_fid &&
@@ -95,10 +96,10 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 		fscache_use_cookie(v9fs_inode_cookie(v9inode),
 				   file->f_mode & FMODE_WRITE);
-	v9fs_open_fid_add(inode, fid);
+	v9fs_open_fid_add(inode, &fid);
 	return 0;
 out_error:
-	p9_client_clunk(file->private_data);
+	p9_fid_put(file->private_data);
 	file->private_data = NULL;
 	return err;
 }