1 files changed, 71 insertions, 36 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 8605155db171..cfc8f81e60d0 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -138,6 +138,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
 		struct fuse_entry_out outarg;
 		struct fuse_conn *fc;
 		struct fuse_req *req;
+		struct dentry *parent;
 
 		/* Doesn't hurt to "reset" the validity timeout */
 		fuse_invalidate_entry_cache(entry);
@@ -151,8 +152,10 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
 		if (IS_ERR(req))
 			return 0;
 
-		fuse_lookup_init(req, entry->d_parent->d_inode, entry, &outarg);
+		parent = dget_parent(entry);
+		fuse_lookup_init(req, parent->d_inode, entry, &outarg);
 		request_send(fc, req);
+		dput(parent);
 		err = req->out.h.error;
 		/* Zero nodeid is same as -ENOENT */
 		if (!err && !outarg.nodeid)
@@ -163,7 +166,9 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
 				fuse_send_forget(fc, req, outarg.nodeid, 1);
 				return 0;
 			}
+			spin_lock(&fc->lock);
 			fi->nlookup ++;
+			spin_unlock(&fc->lock);
 		}
 		fuse_put_request(fc, req);
 		if (err || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
@@ -175,22 +180,6 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
 	return 1;
 }
 
-/*
- * Check if there's already a hashed alias of this directory inode.
- * If yes, then lookup and mkdir must not create a new alias.
- */
-static int dir_alias(struct inode *inode)
-{
-	if (S_ISDIR(inode->i_mode)) {
-		struct dentry *alias = d_find_alias(inode);
-		if (alias) {
-			dput(alias);
-			return 1;
-		}
-	}
-	return 0;
-}
-
 static int invalid_nodeid(u64 nodeid)
 {
 	return !nodeid || nodeid == FUSE_ROOT_ID;
@@ -206,6 +195,24 @@ static int valid_mode(int m)
 		S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
 }
 
+/*
+ * Add a directory inode to a dentry, ensuring that no other dentry
+ * refers to this inode.  Called with fc->inst_mutex.
+ */
+static int fuse_d_add_directory(struct dentry *entry, struct inode *inode)
+{
+	struct dentry *alias = d_find_alias(inode);
+	if (alias) {
+		/* This tries to shrink the subtree below alias */
+		fuse_invalidate_entry(alias);
+		dput(alias);
+		if (!list_empty(&inode->i_dentry))
+			return -EBUSY;
+	}
+	d_add(entry, inode);
+	return 0;
+}
+
 static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
 				  struct nameidata *nd)
 {
@@ -241,11 +248,17 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
 	if (err && err != -ENOENT)
 		return ERR_PTR(err);
 
-	if (inode && dir_alias(inode)) {
-		iput(inode);
-		return ERR_PTR(-EIO);
-	}
-	d_add(entry, inode);
+	if (inode && S_ISDIR(inode->i_mode)) {
+		mutex_lock(&fc->inst_mutex);
+		err = fuse_d_add_directory(entry, inode);
+		mutex_unlock(&fc->inst_mutex);
+		if (err) {
+			iput(inode);
+			return ERR_PTR(err);
+		}
+	} else
+		d_add(entry, inode);
+
 	entry->d_op = &fuse_dentry_operations;
 	if (!err)
 		fuse_change_timeout(entry, &outarg);
@@ -401,12 +414,22 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_req *req,
 	}
 	fuse_put_request(fc, req);
 
-	if (dir_alias(inode)) {
-		iput(inode);
-		return -EIO;
-	}
+	if (S_ISDIR(inode->i_mode)) {
+		struct dentry *alias;
+		mutex_lock(&fc->inst_mutex);
+		alias = d_find_alias(inode);
+		if (alias) {
+			/* New directory must have moved since mkdir */
+			mutex_unlock(&fc->inst_mutex);
+			dput(alias);
+			iput(inode);
+			return -EBUSY;
+		}
+		d_instantiate(entry, inode);
+		mutex_unlock(&fc->inst_mutex);
+	} else
+		d_instantiate(entry, inode);
 
-	d_instantiate(entry, inode);
 	fuse_change_timeout(entry, &outarg);
 	fuse_invalidate_attr(dir);
 	return 0;
@@ -935,14 +958,30 @@ static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg)
 	}
 }
 
+static void fuse_vmtruncate(struct inode *inode, loff_t offset)
+{
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	int need_trunc;
+
+	spin_lock(&fc->lock);
+	need_trunc = inode->i_size > offset;
+	i_size_write(inode, offset);
+	spin_unlock(&fc->lock);
+
+	if (need_trunc) {
+		struct address_space *mapping = inode->i_mapping;
+		unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
+		truncate_inode_pages(mapping, offset);
+	}
+}
+
 /*
  * Set attributes, and at the same time refresh them.
  *
  * Truncation is slightly complicated, because the 'truncate' request
  * may fail, in which case we don't want to touch the mapping.
- * vmtruncate() doesn't allow for this case.  So do the rlimit
- * checking by hand and call vmtruncate() only after the file has
- * actually been truncated.
+ * vmtruncate() doesn't allow for this case, so do the rlimit checking
+ * and the actual truncation by hand.
  */
 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
 {
@@ -993,12 +1032,8 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr)
 			make_bad_inode(inode);
 			err = -EIO;
 		} else {
-			if (is_truncate) {
-				loff_t origsize = i_size_read(inode);
-				i_size_write(inode, outarg.attr.size);
-				if (origsize > outarg.attr.size)
-					vmtruncate(inode, outarg.attr.size);
-			}
+			if (is_truncate)
+				fuse_vmtruncate(inode, outarg.attr.size);
 			fuse_change_attributes(inode, &outarg.attr);
 			fi->i_time = time_to_jiffies(outarg.attr_valid,
 						     outarg.attr_valid_nsec);