nfs4: Add support for server migration

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

@@ -11,14 +11,21 @@
 
 #include <string.h>
 
-#include "Request.h"
+#include <arpa/inet.h>
+#include <net/dns_resolver.h>
 
+#include "Request.h"
 #include "Inode.h"
 
 
+extern RPC::ServerManager* gRPCServerManager;
+extern RPC::ProgramData* CreateNFS4Server(RPC::Server* serv);
+
+
 Filesystem::Filesystem()
 	:
 	fPath(NULL),
+	fName(NULL),
 	fId(1)
 {
 }
@@ -26,10 +33,27 @@ Filesystem::Filesystem()
 
 Filesystem::~Filesystem()
 {
+	free(const_cast<char*>(fName));
 	free(const_cast<char*>(fPath));
 }
 
 
+static const char*
+sGetPath(const char* root, const char* path)
+{
+	int slash = 0;
+	for (int i = 0; path[i] != '\0'; i++) {
+		if (path[i] != root[i] || root[i] == '\0')
+			break;
+
+		if (path[i] == '/')
+			slash = i;
+	}
+
+	return path + slash;
+}
+
+
 status_t
 Filesystem::Mount(Filesystem** pfs, RPC::Server* serv, const char* fsPath,
 	dev_t id)
@@ -67,7 +91,7 @@ Filesystem::Mount(Filesystem** pfs, RPC::Server* serv, const char* fsPath,
 	req.GetFH();
 	req.Access();
 
-	Attribute attr[] = { FATTR4_FSID };
+	Attribute attr[] = { FATTR4_FSID, FATTR4_FS_LOCATIONS };
 	req.GetAttr(attr, sizeof(attr) / sizeof(Attribute));
 
 	status_t result = request.Send();
@@ -110,15 +134,39 @@ Filesystem::Mount(Filesystem** pfs, RPC::Server* serv, const char* fsPath,
 		reinterpret_cast<FilesystemId*>(values[0].fData.fPointer);
 
 	Filesystem* fs = new(std::nothrow) Filesystem;
+
+	if (count == 2 && values[1].fAttribute == FATTR4_FS_LOCATIONS) {
+		FSLocations* locs =
+			reinterpret_cast<FSLocations*>(values[1].fData.fLocations);
+
+		fs->fPath = strdup(locs->fRootPath);
+
+		delete locs;
+	} else
+		fs->fPath = NULL;
+
+	const char* name;
 	if (fsPath != NULL && fsPath[0] == '/')
-		fs->fPath = strdup(fsPath + 1);
-	else
-		fs->fPath = strdup(fsPath + 1);
+		fsPath++;
+	name = strrchr(fsPath, '/');
+	if (name != NULL) {
+		name++;
+		fs->fName = strdup(name);
+	} else
+		fs->fName = strdup(fsPath);
+
 	memcpy(&fs->fRootFH, &fh, sizeof(Filehandle));
 	fs->fServer = serv;
 	fs->fDevId = id;
 	fs->fFsId = *fsid;
 
+	FileInfo fi;
+	fi.fFH = fh;
+	fi.fParent = fh;
+	fi.fName = strdup("/");
+	fi.fPath = strdup(sGetPath(fs->fPath, fsPath));
+	fs->fRoot = fi;
+
 	*pfs = fs;
 
 	return B_OK;
@@ -149,14 +197,8 @@ Filesystem::GetInode(ino_t id, Inode** _inode)
 Inode*
 Filesystem::CreateRootInode()
 {
-	FileInfo fi;
-	fi.fFH = fRootFH;
-	fi.fParent = fRootFH;
-	fi.fName = strdup("/");
-	fi.fPath = strdup(fPath);
-
 	Inode* inode;
-	status_t result = Inode::CreateInode(this, fi, &inode);
+	status_t result = Inode::CreateInode(this, fRoot, &inode);
 	if (result == B_OK)
 		return inode;
 	else
@@ -229,12 +271,95 @@ Filesystem::ReadInfo(struct fs_info* info)
 	}
 
 	info->flags = B_FS_IS_READONLY;
-	const char* name = strrchr(fPath, '/');
-	if (name != NULL) {
-		name++;
-		strncpy(info->volume_name, name, B_FILE_NAME_LENGTH);
-	} else
-		strncpy(info->volume_name, fPath, B_FILE_NAME_LENGTH);
+	strncpy(info->volume_name, fName, B_FILE_NAME_LENGTH);
+
+	return B_OK;
+}
+
+
+status_t
+Filesystem::Migrate(const Filehandle& fh, const RPC::Server* serv)
+{
+	mutex_lock(&fMigrationLock);
+	if (serv != fServer) {
+		mutex_unlock(&fMigrationLock);
+		return B_OK;
+	}
+
+	Request request(fServer);
+	RequestBuilder& req = request.Builder();
+
+	req.PutFH(fh);
+	Attribute attr[] = { FATTR4_FS_LOCATIONS };
+	req.GetAttr(attr, sizeof(attr) / sizeof(Attribute));
+
+	status_t result = request.Send();
+	if (result != B_OK) {
+		mutex_unlock(&fMigrationLock);
+		return result;
+	}
+
+	ReplyInterpreter& reply = request.Reply();
+
+	result = reply.PutFH();
+	if (result != B_OK) {
+		mutex_unlock(&fMigrationLock);
+		return result;
+	}
+
+	AttrValue* values;
+	uint32 count;
+	result = reply.GetAttr(&values, &count);
+	if (result != B_OK || count < 1) {
+		mutex_unlock(&fMigrationLock);
+		return result;
+	}
+
+	FSLocations* locs =
+		reinterpret_cast<FSLocations*>(values[0].fData.fLocations);
+
+	dns_resolver_module* dns;
+	result = get_module(DNS_RESOLVER_MODULE_NAME,
+		reinterpret_cast<module_info**>(&dns));
+	if (result != B_OK) {
+		mutex_unlock(&fMigrationLock);
+		return result;
+	}
+
+	RPC::Server* server = fServer;
+	for (uint32 i = 0; i < locs->fCount; i++) {
+		for (uint32 j = 0; j < locs->fLocations[i].fCount; j++) {
+			uint32 ip;
+			struct in_addr addr;
+			if (inet_aton(locs->fLocations[i].fLocations[j], &addr) == 0) {
+					result = dns->dns_resolve(locs->fLocations[i].fLocations[j],
+						&ip);
+					if (result != B_OK)
+						continue;
+			} else
+				ip = addr.s_addr;
+
+			if (gRPCServerManager->Acquire(&fServer, ip, 2049,
+				ProtocolUDP, CreateNFS4Server) == B_OK) {
+
+				free(const_cast<char*>(fPath));
+				fPath = strdup(locs->fLocations[j].fRootPath);
+				break;
+			}
+		}
+	}
+
+	put_module(DNS_RESOLVER_MODULE_NAME);
+	delete locs;
+
+	if (server == fServer) {
+		mutex_unlock(&fMigrationLock);
+		return B_ERROR;
+	}
+
+	gRPCServerManager->Release(server);
+
+	mutex_unlock(&fMigrationLock);
 
 	return B_OK;
 }

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

@@ -30,9 +30,13 @@ public:
 
 			status_t			ReadInfo(struct fs_info* info);
 
+			status_t			Migrate(const Filehandle& fh,
+									const RPC::Server* serv);
+
 	inline	RPC::Server*		Server();
 	inline	NFS4Server*			NFSServer();
 
+	inline	const char*			Path() const;
 	inline	const FilesystemId&	FsId() const;
 
 	inline	uint64				AllocFileId();
@@ -42,9 +46,12 @@ public:
 private:
 								Filesystem();
 
-			const char*			fPath;
 			FilesystemId		fFsId;
+			const char*			fPath;
+			mutex				fMigrationLock;
 
+			const char*			fName;
+			FileInfo			fRoot;
 			Filehandle			fRootFH;
 
 			RPC::Server*		fServer;
@@ -70,6 +77,13 @@ Filesystem::NFSServer()
 }
 
 
+inline const char*
+Filesystem::Path() const
+{
+	return fPath;
+}
+
+
 inline const FilesystemId&
 Filesystem::FsId() const
 {

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

@@ -37,7 +37,8 @@ Inode::CreateInode(Filesystem* fs, const FileInfo &fi, Inode** _inode)
 	inode->fPath = strdup(fi.fPath);
 
 	do {
-		Request request(fs->Server());
+		RPC::Server* serv = fs->Server();
+		Request request(serv);
 		RequestBuilder& req = request.Builder();
 
 		req.PutFH(inode->fHandle);
@@ -57,6 +58,12 @@ Inode::CreateInode(Filesystem* fs, const FileInfo &fi, Inode** _inode)
 			continue;
 		}
 
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fs->Migrate(inode->fHandle, serv);
+			continue;
+		}
+
 		result = reply.PutFH();
 		if (result != B_OK)
 			return result;
@@ -113,7 +120,8 @@ Inode::LookUp(const char* name, ino_t* id)
 	}
 
 	do {
-		Request request(fFilesystem->Server());
+		RPC::Server* serv = fFilesystem->Server();
+		Request request(serv);
 		RequestBuilder& req = request.Builder();
 
 		req.PutFH(fHandle);
@@ -140,6 +148,12 @@ Inode::LookUp(const char* name, ino_t* id)
 			continue;
 		}
 
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fFilesystem->Migrate(fHandle, serv);
+			continue;
+		}
+
 		result = reply.PutFH();
 		if (result != B_OK)
 			return result;
@@ -206,7 +220,8 @@ Inode::ReadLink(void* buffer, size_t* length)
 		return B_BAD_VALUE;
 
 	do {
-		Request request(fFilesystem->Server());
+		RPC::Server* serv = fFilesystem->Server();
+		Request request(serv);
 		RequestBuilder& req = request.Builder();
 
 		req.PutFH(fHandle);
@@ -224,6 +239,12 @@ Inode::ReadLink(void* buffer, size_t* length)
 			continue;
 		}
 
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fFilesystem->Migrate(fHandle, serv);
+			continue;
+		}
+
 		result = reply.PutFH();
 		if (result != B_OK)
 			return result;
@@ -241,7 +262,8 @@ status_t
 Inode::Access(int mode)
 {
 	do {
-		Request request(fFilesystem->Server());
+		RPC::Server* serv = fFilesystem->Server();
+		Request request(serv);
 		RequestBuilder& req = request.Builder();
 
 		req.PutFH(fHandle);
@@ -259,6 +281,12 @@ Inode::Access(int mode)
 			continue;
 		}
 
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fFilesystem->Migrate(fHandle, serv);
+			continue;
+		}
+
 		result = reply.PutFH();
 		if (result != B_OK)
 			return result;
@@ -293,7 +321,8 @@ status_t
 Inode::Stat(struct stat* st)
 {
 	do {
-		Request request(fFilesystem->Server());
+		RPC::Server* serv = fFilesystem->Server();
+		Request request(serv);
 		RequestBuilder& req = request.Builder();
 
 		req.PutFH(fHandle);
@@ -315,6 +344,12 @@ Inode::Stat(struct stat* st)
 			continue;
 		}
 
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fFilesystem->Migrate(fHandle, serv);
+			continue;
+		}
+
 		result = reply.PutFH();
 		if (result != B_OK)
 			return result;
@@ -419,7 +454,8 @@ Inode::Open(int mode, OpenFileCookie* cookie)
 	do {
 		cookie->fClientId = fFilesystem->NFSServer()->ClientId();
 
-		Request request(fFilesystem->Server());
+		RPC::Server* serv = fFilesystem->Server();
+		Request request(serv);
 		RequestBuilder& req = request.Builder();
 
 		cookie->fOwnerId = atomic_add64(&cookie->fLastOwnerId, 1);
@@ -440,6 +476,12 @@ Inode::Open(int mode, OpenFileCookie* cookie)
 			continue;
 		}
 
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fFilesystem->Migrate(fHandle, serv);
+			continue;
+		}
+
 		// server is in grace period, we need to wait
 		if (reply.NFS4Error() == NFS4ERR_GRACE) {
 			fFilesystem->NFSServer()->ReleaseCID(cookie->fClientId);
@@ -501,7 +543,8 @@ Inode::Close(OpenFileCookie* cookie)
 	fFilesystem->NFSServer()->RemoveOpenFile(cookie);
 
 	do {
-		Request request(fFilesystem->Server());
+		RPC::Server* serv = fFilesystem->Server();
+		Request request(serv);
 		RequestBuilder& req = request.Builder();
 
 		req.PutFH(fHandle);
@@ -520,6 +563,12 @@ Inode::Close(OpenFileCookie* cookie)
 			continue;
 		}
 
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fFilesystem->Migrate(fHandle, serv);
+			continue;
+		}
+
 		// server is in grace period, we need to wait
 		if (reply.NFS4Error() == NFS4ERR_GRACE) {
 			snooze_etc(fFilesystem->NFSServer()->LeaseTime() / 3,
@@ -553,7 +602,8 @@ Inode::Read(OpenFileCookie* cookie, off_t pos, void* buffer, size_t* _length)
 
 	while (size < *_length && !eof) {
 		do {
-			Request request(fFilesystem->Server());
+			RPC::Server* serv = fFilesystem->Server();
+			Request request(serv);
 			RequestBuilder& req = request.Builder();
 
 			req.PutFH(fHandle);
@@ -572,6 +622,12 @@ Inode::Read(OpenFileCookie* cookie, off_t pos, void* buffer, size_t* _length)
 				continue;
 			}
 
+			// filesystem has been moved
+			if (reply.NFS4Error() == NFS4ERR_MOVED) {
+				fFilesystem->Migrate(fHandle, serv);
+				continue;
+			}
+
 			// server is in grace period, we need to wait
 			if (reply.NFS4Error() == NFS4ERR_GRACE) {
 				snooze_etc(fFilesystem->NFSServer()->LeaseTime() / 3,
@@ -614,7 +670,8 @@ Inode::OpenDir(uint64* cookie)
 		return B_NOT_A_DIRECTORY;
 
 	do {
-		Request request(fFilesystem->Server());
+		RPC::Server* serv = fFilesystem->Server();
+		Request request(serv);
 		RequestBuilder& req = request.Builder();
 
 		req.PutFH(fHandle);
@@ -632,6 +689,12 @@ Inode::OpenDir(uint64* cookie)
 			continue;
 		}
 
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fFilesystem->Migrate(fHandle, serv);
+			continue;
+		}
+
 		result = reply.PutFH();
 		if (result != B_OK)
 			return result;
@@ -657,7 +720,8 @@ Inode::_ReadDirOnce(DirEntry** dirents, uint32* count, uint64* cookie,
 	bool* eof)
 {
 	do {
-		Request request(fFilesystem->Server());
+		RPC::Server* serv = fFilesystem->Server();
+		Request request(serv);
 		RequestBuilder& req = request.Builder();
 
 		req.PutFH(fHandle);
@@ -677,6 +741,12 @@ Inode::_ReadDirOnce(DirEntry** dirents, uint32* count, uint64* cookie,
 			continue;
 		}
 
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fFilesystem->Migrate(fHandle, serv);
+			continue;
+		}
+
 		result = reply.PutFH();
 		if (result != B_OK)
 			return result;
@@ -712,7 +782,8 @@ status_t
 Inode::_ReadDirUp(struct dirent* de, uint32 pos, uint32 size)
 {
 	do {
-		Request request(fFilesystem->Server());
+		RPC::Server* serv = fFilesystem->Server();
+		Request request(serv);
 		RequestBuilder& req = request.Builder();
 
 		req.PutFH(fHandle);
@@ -733,6 +804,12 @@ Inode::_ReadDirUp(struct dirent* de, uint32 pos, uint32 size)
 			continue;
 		}
 
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fFilesystem->Migrate(fHandle, serv);
+			continue;
+		}
+
 		result = reply.PutFH();
 		if (result != B_OK)
 			return result;
@@ -849,16 +926,10 @@ Inode::ReadDir(void* _buffer, uint32 size, uint32* _count, uint64* cookie)
 }
 
 
-status_t
-Inode::_LookUpFilehandle()
+static status_t
+sParsePath(RequestBuilder& req, uint32* count, const char* _path)
 {
-	Request request(fFilesystem->Server());
-	RequestBuilder& req = request.Builder();
-
-	req.PutRootFH();
-
-	uint32 lookupCount = 0;
-	char* path = strdup(fPath);
+	char* path = strdup(_path);
 	char* pathStart = path;
 	char* pathEnd;
 	while (pathStart != NULL) {
@@ -873,10 +944,27 @@ Inode::_LookUpFilehandle()
 		else
 			pathStart = NULL;
 
-		lookupCount++;
+		(*count)++;
 	}
 	free(path);
 
+	return B_OK;
+}
+
+
+status_t
+Inode::_LookUpFilehandle()
+{
+	Request request(fFilesystem->Server());
+	RequestBuilder& req = request.Builder();
+
+	req.PutRootFH();
+
+	uint32 lookupCount = 0;
+
+	sParsePath(req, &lookupCount, fFilesystem->Path());
+	sParsePath(req, &lookupCount, fPath);
+
 	req.GetFH();
 
 	status_t result = request.Send();

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

@@ -14,6 +14,22 @@
 #include <util/kernel_cpp.h>
 
 
+FSLocation::~FSLocation()
+{
+	free(const_cast<char*>(fRootPath));
+	for (uint32 i = 0; i < fCount; i++)
+		free(const_cast<char*>(fLocations[i]));
+	delete[] fLocations;
+}
+
+
+FSLocations::~FSLocations()
+{
+	free(const_cast<char*>(fRootPath));
+	delete[] fLocations;
+}
+
+
 AttrValue::AttrValue()
 	:
 	fFreePointer(false)
@@ -25,6 +41,8 @@ AttrValue::~AttrValue()
 {
 	if (fFreePointer)
 		free(fData.fPointer);
+	if (fAttribute == FATTR4_FS_LOCATIONS)
+		delete fData.fLocations;
 }
 
 
@@ -285,6 +303,30 @@ ReplyInterpreter::SetClientID(uint64* clientid, uint64* verifier)
 }
 
 
+static const char*
+sFlattenPathname(XDR::ReadStream& str)
+{
+	uint32 count = str.GetUInt();
+	char* pathname = NULL;
+	uint32 size = 0;
+	for (uint32 i = 0; i < count; i++) {
+		const char* path = str.GetString();
+		size += strlen(path) + 1;
+		if (pathname == NULL) {
+			pathname = reinterpret_cast<char*>(malloc(strlen(path + 1)));
+			pathname[0] = '\0';
+		} else {
+			*pathname++ = '/';
+			pathname = reinterpret_cast<char*>(realloc(pathname, size));
+		}
+		strcat(pathname, path);
+		free(const_cast<char*>(path));
+	}
+
+	return pathname;
+}
+
+
 status_t
 ReplyInterpreter::_DecodeAttrs(XDR::ReadStream& str, AttrValue** attrs,
 	uint32* count)
@@ -374,6 +416,25 @@ ReplyInterpreter::_DecodeAttrs(XDR::ReadStream& str, AttrValue** attrs,
 		current++;
 	}
 
+	if (sIsAttrSet(FATTR4_FS_LOCATIONS, bitmap, bcount)) {
+		values[current].fAttribute = FATTR4_FS_LOCATIONS;
+
+		FSLocations* locs = new FSLocations;
+		locs->fRootPath = sFlattenPathname(stream);
+		locs->fCount = stream.GetUInt();
+		locs->fLocations = new FSLocation[locs->fCount];
+		for (uint32 i = 0; i < locs->fCount; i++) {
+			locs->fLocations[i].fRootPath = sFlattenPathname(stream);
+			locs->fLocations[i].fCount = stream.GetUInt();
+			locs->fLocations[i].fLocations =
+				new const char*[locs->fLocations[i].fCount];
+			for (uint32 j = 0; j < locs->fLocations[i].fCount; j++)
+				locs->fLocations[i].fLocations[j] = stream.GetString();
+		}
+		values[current].fData.fLocations = locs;
+		current++;
+	}
+
 	if (sIsAttrSet(FATTR4_MAXREAD, bitmap, bcount)) {
 		values[current].fAttribute = FATTR4_MAXREAD;
 		values[current].fData.fValue64 = stream.GetUHyper();

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

@@ -15,6 +15,22 @@
 #include "RPCReply.h"
 
 
+struct FSLocation {
+	const char*			fRootPath;
+	const char**		fLocations;
+	uint32				fCount;
+
+						~FSLocation();
+};
+
+struct FSLocations {
+	const char*			fRootPath;
+	FSLocation*			fLocations;
+	uint32				fCount;
+
+						~FSLocations();
+};
+
 struct AttrValue {
 			AttrValue();
 			~AttrValue();
@@ -25,6 +41,7 @@ struct AttrValue {
 			uint32			fValue32;
 			uint64			fValue64;
 			void*			fPointer;
+			FSLocations*	fLocations;
 	} fData;
 };
 

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

@@ -32,8 +32,8 @@ dprintf(const char* format, ...);
 RPC::ServerManager* gRPCServerManager;
 
 
-static RPC::ProgramData*
-sCreateNFS4Server(RPC::Server* serv)
+RPC::ProgramData*
+CreateNFS4Server(RPC::Server* serv)
 {
 	return new NFS4Server(serv);
 }
@@ -96,7 +96,7 @@ nfs4_mount(fs_volume* volume, const char* device, uint32 flags,
 
 	RPC::Server *server;
 	result = gRPCServerManager->Acquire(&server, ip, 2049, ProtocolUDP,
-		sCreateNFS4Server);
+		CreateNFS4Server);
 	if (result != B_OK)
 		return result;