nfs4: Fix problems with reading directory entries

* Inode::ReadDir missed an entry when given buffer was too small
 * Each OpenDirCookie now has its own copy of directory snapshot what
   would prevent Inode::ReadDir from accessing freed memory when removing
   files and reading directory entries simultaneously
 * Several minor issues fixed

src/add-ons/kernel/file_systems/nfs4/DirectoryCache.cpp

@@ -25,6 +25,14 @@ NameCacheEntry::NameCacheEntry(const char* name, ino_t node)
 }
 
 
+NameCacheEntry::NameCacheEntry(const NameCacheEntry& entry)
+	:
+	fNode(entry.fNode),
+	fName(strdup(entry.fName))
+{
+}
+
+
 NameCacheEntry::~NameCacheEntry()
 {
 	free(const_cast<char*>(fName));
@@ -37,6 +45,26 @@ DirectoryCacheSnapshot::DirectoryCacheSnapshot()
 }
 
 
+DirectoryCacheSnapshot::DirectoryCacheSnapshot(
+	const DirectoryCacheSnapshot& snapshot)
+{
+	mutex_init(&fLock, NULL);
+
+	MutexLocker _(snapshot.fLock);
+	NameCacheEntry* entry = snapshot.fEntries.Head();
+	NameCacheEntry* new_entry;
+	while (entry) {
+		new_entry = new NameCacheEntry(*entry);
+		if (new_entry == NULL)
+			break;
+
+		fEntries.Add(new_entry);
+
+		entry = snapshot.fEntries.GetNext(entry);
+	}
+}
+
+
 DirectoryCacheSnapshot::~DirectoryCacheSnapshot()
 {
 	while (!fEntries.IsEmpty()) {

src/add-ons/kernel/file_systems/nfs4/DirectoryCache.h

@@ -24,15 +24,18 @@ struct NameCacheEntry :
 			const char*		fName;
 
 							NameCacheEntry(const char* name, ino_t node);
+							NameCacheEntry(const NameCacheEntry& entry);
 							~NameCacheEntry();
 };
 
 struct DirectoryCacheSnapshot : public KernelReferenceable {
-	SinglyLinkedList<NameCacheEntry>	fEntries;
-	mutex								fLock;
+			SinglyLinkedList<NameCacheEntry>	fEntries;
+	mutable	mutex			fLock;
 
-										DirectoryCacheSnapshot();
-										~DirectoryCacheSnapshot();
+							DirectoryCacheSnapshot();
+							DirectoryCacheSnapshot(
+								const DirectoryCacheSnapshot& snapshot);
+							~DirectoryCacheSnapshot();
 };
 
 class DirectoryCache : public DoublyLinkedListLinkImpl<DirectoryCache> {

src/add-ons/kernel/file_systems/nfs4/Inode.cpp

@@ -250,7 +250,7 @@ Inode::Link(Inode* dir, const char* name)
 			&& dir->fCache->ChangeInfo() == changeInfo.fBefore) {
 			dir->fCache->AddEntry(name, fInfo.fFileId, true);
 			dir->fCache->SetChangeInfo(changeInfo.fAfter);
-		} else if (dir->fCache->ChangeInfo() != changeInfo.fBefore)
+		} else
 			dir->fCache->Trash();
 	}
 	dir->fCache->Unlock();
@@ -428,7 +428,7 @@ Inode::CreateObject(const char* name, const char* path, int mode, FileType type,
 		if (changeInfo.fAtomic && fCache->ChangeInfo() == changeInfo.fBefore) {
 			fCache->AddEntry(name, fileID, true);
 			fCache->SetChangeInfo(changeInfo.fAfter);
-		} else if (fCache->ChangeInfo() != changeInfo.fBefore)
+		} else
 			fCache->Trash();
 	}
 	fCache->Unlock();

src/add-ons/kernel/file_systems/nfs4/InodeDir.cpp

@@ -123,7 +123,7 @@ Inode::FillDirEntry(struct dirent* de, ino_t id, const char* name, uint32 pos,
 	ASSERT(de != NULL);
 	ASSERT(name != NULL);
 
-	uint32 nameSize = strlen(name);
+	uint32 nameSize = strlen(name) + 1;
 	const uint32 entSize = sizeof(struct dirent);
 
 	if (pos + entSize + nameSize > size)
@@ -282,7 +282,7 @@ Inode::GetDirSnapshot(DirectoryCacheSnapshot** _snapshot,
 				free(const_cast<char*>(name));
 
 			if (entry == NULL || entry->fName == NULL) {
-				if (entry->fName == NULL)
+				if (entry != NULL)
 					delete entry;
 				delete snapshot;
 				delete[] dirents;
@@ -324,10 +324,10 @@ Inode::ReadDir(void* _buffer, uint32 size, uint32* _count,
 		else
 			fFileSystem->Revalidator().RemoveDirectory(cache);
 
-		cookie->fSnapshot = cache->GetSnapshot();
-		if (cookie->fSnapshot == NULL) {
+		DirectoryCacheSnapshot* snapshot = cache->GetSnapshot();
+		if (snapshot == NULL) {
 			uint64 change;
-			result = GetDirSnapshot(&cookie->fSnapshot, cookie, &change,
+			result = GetDirSnapshot(&snapshot, cookie, &change,
 				cookie->fAttrDir);
 			if (result != B_OK) {
 				cache->Unlock();
@@ -335,9 +335,9 @@ Inode::ReadDir(void* _buffer, uint32 size, uint32* _count,
 				return result;
 			}
 			cache->ValidateChangeInfo(change);
-			cache->SetSnapshot(cookie->fSnapshot);
+			cache->SetSnapshot(snapshot);
 		}
-		cookie->fSnapshot->AcquireReference();
+		cookie->fSnapshot = new DirectoryCacheSnapshot(*snapshot);
 		fFileSystem->Revalidator().AddDirectory(cache);
 		cache->Unlock();
 		fFileSystem->Revalidator().Unlock();
@@ -387,6 +387,7 @@ Inode::ReadDir(void* _buffer, uint32 size, uint32* _count,
 	MutexLocker _(cookie->fSnapshot->fLock);
 	for (; !overflow && i < *_count; i++) {
 		struct dirent* de = reinterpret_cast<dirent*>(buffer + pos);
+		NameCacheEntry* temp = cookie->fCurrent;
 
 		if (cookie->fCurrent == NULL)
 			cookie->fCurrent = cookie->fSnapshot->fEntries.Head();
@@ -402,6 +403,7 @@ Inode::ReadDir(void* _buffer, uint32 size, uint32* _count,
 
 		if (FillDirEntry(de, cookie->fCurrent->fNode, cookie->fCurrent->fName,
 			pos, size) == B_BUFFER_OVERFLOW) {
+			cookie->fCurrent = temp;
 			overflow = true;
 			break;
 		}

src/add-ons/kernel/file_systems/nfs4/InodeRegular.cpp

@@ -52,7 +52,7 @@ Inode::CreateState(const char* name, int mode, int perms, OpenState* state,
 			&& fCache->ChangeInfo() == changeInfo.fBefore) {
 			fCache->AddEntry(name, fileID, true);
 			fCache->SetChangeInfo(changeInfo.fAfter);
-		} else if (fCache->ChangeInfo() != changeInfo.fBefore)
+		} else
 			fCache->Trash();
 	}
 	fCache->Unlock();

src/add-ons/kernel/file_systems/nfs4/ReplyInterpreter.cpp

@@ -421,10 +421,7 @@ ReplyInterpreter::ReadDir(uint64* cookie, uint64* cookieVerf,
 
 		isNext = fReply->Stream().GetBoolean();
 	}
-	if (!isNext)
-		*eof = fReply->Stream().GetBoolean();
-	else
-		*eof = false;
+	*eof = fReply->Stream().GetBoolean();
 
 	*_count = count;
 	*dirents = entries;

src/add-ons/kernel/file_systems/nfs4/kernel_interface.cpp

@@ -1039,6 +1039,9 @@ nfs4_rewind_dir(fs_volume* volume, fs_vnode* vnode, void* _cookie)
 
 	OpenDirCookie* cookie = reinterpret_cast<OpenDirCookie*>(_cookie);
 	cookie->fSpecial = 0;
+	if (cookie->fSnapshot != NULL)
+		cookie->fSnapshot->ReleaseReference();
+	cookie->fSnapshot = NULL;
 	cookie->fCurrent = NULL;
 	cookie->fEOF = false;