nfs4: Add support for O_APPEND mode

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

@@ -1022,21 +1022,39 @@ Inode::Read(OpenFileCookie* cookie, off_t pos, void* buffer, size_t* _length)
 
 status_t
 Inode::Write(OpenFileCookie* cookie, off_t pos, const void* _buffer,
-	size_t length)
+	size_t *_length)
 {
 	uint32 size = 0;
 	uint32 len = 0;
+	uint64 fileSize;
 	const char* buffer = reinterpret_cast<const char*>(_buffer);
 
-	while (size < length) {
+	while (size < *_length) {
 		do {
 			RPC::Server* serv = fFilesystem->Server();
 			Request request(serv);
 			RequestBuilder& req = request.Builder();
 
+			if (size == 0 && (cookie->fMode & O_APPEND) == O_APPEND) {
+				struct stat st;
+				status_t result = Stat(&st);
+				if (result != B_OK)
+					return result;
+
+				fileSize = st.st_size;
+				pos = fileSize;
+			}
+
 			req.PutFH(fHandle);
+			if ((cookie->fMode & O_APPEND) == O_APPEND) {
+				AttrValue attr;
+				attr.fAttribute = FATTR4_SIZE;
+				attr.fFreePointer = false;
+				attr.fData.fValue64 = fileSize + size;
+				req.Verify(&attr, 1);
+			}
 			req.Write(cookie->fStateId, cookie->fStateSeq, buffer + size,
-				pos + size, length - size);
+				pos + size, *_length - size);
 
 			status_t result = request.Send(cookie);
 			if (result != B_OK)
@@ -1044,6 +1062,16 @@ Inode::Write(OpenFileCookie* cookie, off_t pos, const void* _buffer,
 
 			ReplyInterpreter& reply = request.Reply();
 
+			// append: race condition
+			if (reply.NFS4Error() == NFS4ERR_NOT_SAME) {
+				if (size == 0)
+					continue;
+				else {
+					*_length = size;
+					return B_OK;
+				}
+			}
+
 			// filehandle has expired
 			if (reply.NFS4Error() == NFS4ERR_FHEXPIRED) {
 				_LookUpFilehandle();
@@ -1074,6 +1102,12 @@ Inode::Write(OpenFileCookie* cookie, off_t pos, const void* _buffer,
 			if (result != B_OK)
 				return result;
 
+			if ((cookie->fMode & O_APPEND) == O_APPEND) {
+				result = reply.Verify();
+				if (result != B_OK)
+					return result;
+			}
+
 			result = reply.Write(&len);
 			if (result != B_OK)
 				return result;
@@ -1084,6 +1118,8 @@ Inode::Write(OpenFileCookie* cookie, off_t pos, const void* _buffer,
 		} while (true);
 	}
 
+	*_length = size;
+
 	return B_OK;
 }
 

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

@@ -50,7 +50,7 @@ public:
 					status_t	Read(OpenFileCookie* cookie, off_t pos,
 									void* buffer, size_t* length);
 					status_t	Write(OpenFileCookie* cookie, off_t pos,
-									const void* buffer, size_t length);
+									const void* buffer, size_t *_length);
 
 					status_t	OpenDir(OpenDirCookie* cookie);
 					status_t	ReadDir(void* buffer, uint32 size,

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

@@ -573,6 +573,11 @@ RequestBuilder::_EncodeAttrs(XDR::WriteStream& stream, AttrValue* attr,
 		i++;
 	}
 
+	if (i < count && attr[i].fAttribute == FATTR4_SIZE) {
+		str.AddUHyper(attr[i].fData.fValue64);
+		i++;
+	}
+
 	if (i < count && attr[i].fAttribute == FATTR4_MODE) {
 		str.AddUInt(attr[i].fData.fValue32);
 		i++;

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

@@ -372,7 +372,7 @@ nfs4_write(fs_volume* volume, fs_vnode* vnode, void* _cookie, off_t pos,
 
 	OpenFileCookie* cookie = reinterpret_cast<OpenFileCookie*>(_cookie);
 
-	return inode->Write(cookie, pos, buffer, *length);
+	return inode->Write(cookie, pos, buffer, length);
 }