diff --git a/src/add-ons/kernel/file_systems/nfs4/Cookie.cpp b/src/add-ons/kernel/file_systems/nfs4/Cookie.cpp
index 0275fd41e5..935afbb339 100644
--- a/src/add-ons/kernel/file_systems/nfs4/Cookie.cpp
+++ b/src/add-ons/kernel/file_systems/nfs4/Cookie.cpp
@@ -147,7 +147,9 @@ Cookie::CancelAll()
 
 OpenStateCookie::OpenStateCookie(FileSystem* fileSystem)
 	:
-	Cookie(fileSystem)
+	Cookie(fileSystem),
+	fUid(geteuid()),
+	fGid(getegid())
 {
 }
 
diff --git a/src/add-ons/kernel/file_systems/nfs4/Cookie.h b/src/add-ons/kernel/file_systems/nfs4/Cookie.h
index 056fb5d845..3c9f1983eb 100644
--- a/src/add-ons/kernel/file_systems/nfs4/Cookie.h
+++ b/src/add-ons/kernel/file_systems/nfs4/Cookie.h
@@ -78,6 +78,9 @@ struct OpenStateCookie : public Cookie {
 			OpenState*		fOpenState;
 			uint32			fMode;
 
+			uid_t			fUid;
+			gid_t			fGid;
+
 							OpenStateCookie(FileSystem* fileSystem);
 };
 
diff --git a/src/add-ons/kernel/file_systems/nfs4/Delegation.cpp b/src/add-ons/kernel/file_systems/nfs4/Delegation.cpp
index 18b52b578c..53296dfa04 100644
--- a/src/add-ons/kernel/file_systems/nfs4/Delegation.cpp
+++ b/src/add-ons/kernel/file_systems/nfs4/Delegation.cpp
@@ -20,22 +20,55 @@ Delegation::Delegation(const OpenDelegationData& data, Inode* inode,
 	fData(data),
 	fInode(inode),
 	fAttribute(attribute),
+	fStateSeq(data.fStateSeq),
 	fUid(geteuid()),
-	fGid(getegid())
+	fGid(getegid()),
+	fRecalled(false)
 {
 	ASSERT(inode != NULL);
+	memcpy(fStateID, data.fStateID, sizeof(fStateID));
 }
 
 
 status_t
 Delegation::GiveUp(bool truncate)
 {
+	PrepareGiveUp(truncate);
+
+	return DoGiveUp(truncate);
+}
+
+
+status_t
+Delegation::PrepareGiveUp(bool truncate)
+{
+	status_t status = B_OK;
 	if (!fAttribute && !truncate)
-		fInode->SyncAndCommit(true);
+		status = fInode->Sync(true, false);
 
-	ReturnDelegation();
+	return status;
+}
 
-	return B_OK;
+
+status_t
+Delegation::DoGiveUp(bool truncate, bool wait)
+{
+	if (!fAttribute && !truncate && wait)
+		fInode->WaitAIOComplete();
+
+	status_t status = ReturnDelegation();
+
+	fInode->Commit(fUid, fGid);
+
+	return status;
+}
+
+
+void
+Delegation::GetStateIDandSeq(uint32* stateID, uint32& stateSeq) const
+{
+	memcpy(stateID, fStateID, sizeof(uint32) * 3);
+	stateSeq = fStateSeq;
 }
 
 
diff --git a/src/add-ons/kernel/file_systems/nfs4/Delegation.h b/src/add-ons/kernel/file_systems/nfs4/Delegation.h
index 9d5e16e162..4cb293f5e1 100644
--- a/src/add-ons/kernel/file_systems/nfs4/Delegation.h
+++ b/src/add-ons/kernel/file_systems/nfs4/Delegation.h
@@ -24,10 +24,15 @@ public:
 							uint64 clientID, bool attr = false);
 
 	status_t			GiveUp(bool truncate = false);
+			status_t	PrepareGiveUp(bool truncate);
+			status_t	DoGiveUp(bool truncate, bool wait = true);
 
 	inline	void		SetData(const OpenDelegationData& data);
 	inline	Inode*		GetInode() const;
+			void		GetStateIDandSeq(uint32* stateID, uint32& stateSeq) const;
 	inline	OpenDelegation Type();
+	inline	void		MarkRecalled();
+	inline	bool		RecallInitiated() const;
 
 	void				Dump(void (*xprintf)(const char*, ...) = dprintf) const;
 
@@ -39,8 +44,11 @@ private:
 	OpenDelegationData	fData;
 	Inode*				fInode;
 	bool				fAttribute;
+	uint32				fStateID[3];
+	uint32				fStateSeq;
 	uid_t				fUid;
 	gid_t				fGid;
+	bool				fRecalled;
 };
 
 
@@ -65,5 +73,19 @@ Delegation::Type()
 }
 
 
+inline void
+Delegation::MarkRecalled()
+{
+	fRecalled = true;
+}
+
+
+inline bool
+Delegation::RecallInitiated() const
+{
+	return fRecalled;
+}
+
+
 #endif	// DELEGATION_H
 
diff --git a/src/add-ons/kernel/file_systems/nfs4/Inode.cpp b/src/add-ons/kernel/file_systems/nfs4/Inode.cpp
index fbd516d18d..2bc8fc2fba 100644
--- a/src/add-ons/kernel/file_systems/nfs4/Inode.cpp
+++ b/src/add-ons/kernel/file_systems/nfs4/Inode.cpp
@@ -34,6 +34,7 @@ Inode::Inode()
 	fWriteDirty(false),
 	fAIOWait(create_sem(1, NULL)),
 	fAIOCount(0),
+	fOpenStateReleasesPending(0),
 	fStale(false)
 {
 	rw_lock_init(&fDelegationLock, "nfs4 Inode::fDelegationLock");
@@ -704,12 +705,15 @@ Inode::WriteStat(const struct stat* st, uint32 mask, OpenAttrCookie* cookie)
 		i++;
 	}
 
+	ReadLocker delegationLocker(fDelegationLock);
 	if (cookie == NULL) {
 		MutexLocker stateLocker(fStateLock);
 		ASSERT(fOpenState != NULL || !(mask & B_STAT_SIZE));
-		result = NFS4Inode::WriteStat(fOpenState, attr, i);
-	} else
-		result = NFS4Inode::WriteStat(cookie->fOpenState, attr, i);
+		result = NFS4Inode::WriteStat(fOpenState, fDelegation, attr, i);
+	} else {
+		ASSERT(cookie->fOpenState->fDelegation == fDelegation);
+		result = NFS4Inode::WriteStat(cookie->fOpenState, NULL, attr, i);
+	}
 
 	fMetaCache.InvalidateStat();
 
@@ -974,6 +978,52 @@ Inode::RecallDelegation(bool truncate)
 }
 
 
+/*! Flush write data to the server if needed before returning the delegation.
+	@post If data needs to be flushed, an IO job is enqueued but may not be complete.
+*/
+void
+Inode::PrepareDelegationRecall(bool truncate)
+{
+	rw_lock_write_lock(&fDelegationLock);
+	fDelegation->MarkRecalled();
+	rw_lock_write_unlock(&fDelegationLock);
+
+	ReadLocker _(fDelegationLock);
+	if (fDelegation == NULL)
+		return;
+
+	fDelegation->PrepareGiveUp(truncate);
+
+	return;
+}
+
+
+/*! Return the delegation after data has been flushed to the server.
+	@pre RecallDelegationAsyncPrep has been called.
+*/
+void
+Inode::RecallDelegationAsync(bool truncate)
+{
+	WriteLocker _(fDelegationLock);
+	if (fDelegation == NULL)
+		return;
+
+	fDelegation->DoGiveUp(truncate, false);
+
+	fMetaCache.UnlockValid();
+	fFileSystem->RemoveDelegation(fDelegation);
+
+	MutexLocker stateLocker(fStateLock);
+	fOpenState->fDelegation = NULL;
+	ReleaseOpenState();
+
+	delete fDelegation;
+	fDelegation = NULL;
+
+	return;
+}
+
+
 void
 Inode::RecallReadDelegation()
 {
@@ -1003,27 +1053,90 @@ Inode::ReturnDelegation(bool truncate)
 }
 
 
+/*! Temporarily unlock the locks that need to be acquired by the WorkQueue when a delegation
+	is recalled.
+	@pre fStateLock is locked and fDelegation lock is read-locked.
+*/
+void
+Inode::UnlockAndRelockStateLocks()
+{
+	rw_lock_read_unlock(&fDelegationLock);
+	mutex_unlock(&fStateLock);
+	rw_lock_read_lock(&fDelegationLock);
+	mutex_lock(&fStateLock);
+}
+
+
+/*! Temporarily unlock fWriteLock.  Useful for allowing an IO job to complete.
+	@pre fWriteLock is write-locked and fDelegationLock is read-locked.
+*/
+void
+Inode::UnlockAndRelockWriteLock()
+{
+	rw_lock_write_unlock(&fWriteLock);
+	rw_lock_write_lock(&fWriteLock);
+}
+
+
+/*! Release a reference to fOpenState or set up later release if IO is not complete.
+	@pre fStateLock is locked.
+*/
 void
 Inode::ReleaseOpenState()
 {
 	ASSERT(fOpenState != NULL);
 
-	if (fOpenState->ReleaseReference() == 1) {
-		ASSERT(fAIOCount == 0);
-		fOpenState = NULL;
+	// If IO is pending, wait until it is finished to release the (possibly last) reference.
+	// It would be simpler to call WaitAIOComplete here, but that won't work if this
+	// is the WorkQueue thread.
+	MutexLocker _(fAIOLock);
+	if (fAIOCount > 0) {
+		++fOpenStateReleasesPending;
+	} else {
+		if (fOpenState->ReleaseReference() == 1)
+			fOpenState = NULL;
 	}
+
+	return;
+}
+
+
+/*! Sync file cache data to server.
+	@param wait If true, the function returns only after the sync is finished.
+*/
+status_t
+Inode::Sync(bool force, bool wait)
+{
+	ReadLocker locker(fDelegationLock);
+	if (!force && fDelegation != NULL && fDelegation->Type() == OPEN_DELEGATE_WRITE
+		&& !fDelegation->RecallInitiated()) {
+		locker.Unlock();
+		if (wait == true) {
+			// Wait for any IO jobs that may already be enqueued.
+			WaitAIOComplete();
+		}
+		return B_OK;
+	}
+	locker.Unlock();
+
+	status_t status = file_cache_sync(fFileCache);
+	if (wait == true)
+		WaitAIOComplete();
+
+	return status;
 }
 
 
 status_t
-Inode::SyncAndCommit(bool force)
+Inode::SyncAndCommit(bool force, OpenStateCookie* cookie)
 {
-	if (!force && fDelegation != NULL)
-		return B_OK;
+	Sync(force, true);
 
-	file_cache_sync(fFileCache);
-	WaitAIOComplete();
-	return Commit();
+	// The server is liable to deny a commit request that does not come from a user who
+	// opened the file.
+	uid_t uid = cookie != NULL ? cookie->fUid : geteuid();
+	gid_t gid = cookie != NULL ? cookie->fGid : getegid();
+	return Commit(uid, gid);
 }
 
 
@@ -1040,11 +1153,33 @@ Inode::BeginAIOOp()
 void
 Inode::EndAIOOp()
 {
-	MutexLocker _(fAIOLock);
+	MutexLocker AIOLocker(fAIOLock);
 	ASSERT(fAIOCount > 0);
 	fAIOCount--;
 	if (fAIOCount == 0)
 		release_sem(fAIOWait);
+
+	if (fOpenStateReleasesPending > 0) {
+		MutexLocker stateLocker(fStateLock);
+		--fOpenStateReleasesPending;
+		if (fOpenState->ReleaseReference() == 1) {
+			ASSERT(fAIOCount == 0);
+			ASSERT(fOpenStateReleasesPending == 0);
+			fOpenState = NULL;
+		}
+	}
+}
+
+
+bool
+Inode::AIOIncomplete()
+{
+	MutexLocker _(fAIOLock);
+
+	if (fAIOCount > 0)
+		return true;
+
+	return false;
 }
 
 
diff --git a/src/add-ons/kernel/file_systems/nfs4/Inode.h b/src/add-ons/kernel/file_systems/nfs4/Inode.h
index 9ad3b0f93d..8a339b4736 100644
--- a/src/add-ons/kernel/file_systems/nfs4/Inode.h
+++ b/src/add-ons/kernel/file_systems/nfs4/Inode.h
@@ -40,16 +40,22 @@ public:
 
 	inline			OpenState*	GetOpenState();
 
+	inline			Delegation*	GetDelegation() const;
 					void		SetDelegation(Delegation* delegation);
 					void		RecallDelegation(bool truncate = false);
+					void		PrepareDelegationRecall(bool truncate = false);
+					void		RecallDelegationAsync(bool truncate = false);
 					void		RecallReadDelegation();
+					void		UnlockAndRelockStateLocks();
+					void		UnlockAndRelockWriteLock();
 
 					status_t	LookUp(const char* name, ino_t* id);
 
 					status_t	Access(int mode);
 
-					status_t	Commit();
-					status_t	SyncAndCommit(bool force = false);
+					status_t	Sync(bool force = false, bool wait = true);
+					status_t	Commit(uid_t uid, gid_t gid);
+					status_t	SyncAndCommit(bool force = false, OpenStateCookie* cookie = NULL);
 
 					status_t	CreateObject(const char* name, const char* path,
 									int mode, FileType type, ino_t* id);
@@ -117,6 +123,7 @@ public:
 
 					void		BeginAIOOp();
 					void		EndAIOOp();
+					bool		AIOIncomplete();
 	inline			void		WaitAIOComplete();
 
 	inline			void		SetStale(bool stale = true);
@@ -177,6 +184,7 @@ private:
 					sem_id		fAIOWait;
 					uint32		fAIOCount;
 					mutex		fAIOLock;
+					uint32		fOpenStateReleasesPending;
 
 					bool		fStale;
 };
@@ -266,6 +274,13 @@ Inode::GetOpenState()
 }
 
 
+inline Delegation*
+Inode::GetDelegation() const
+{
+	return fDelegation;
+}
+
+
 inline void
 Inode::SetStale(bool stale)
 {
diff --git a/src/add-ons/kernel/file_systems/nfs4/InodeRegular.cpp b/src/add-ons/kernel/file_systems/nfs4/InodeRegular.cpp
index 25602434ac..610c1a3c14 100644
--- a/src/add-ons/kernel/file_systems/nfs4/InodeRegular.cpp
+++ b/src/add-ons/kernel/file_systems/nfs4/InodeRegular.cpp
@@ -115,6 +115,7 @@ Inode::Open(int mode, OpenFileCookie* cookie)
 		state->fInfo = fInfo;
 		state->fFileSystem = fFileSystem;
 		state->fMode = mode & O_RWMASK;
+		state->fDelegation = fDelegation;
 		status_t result = OpenFile(state, mode, &data);
 		if (result != B_OK) {
 			delete state;
@@ -125,8 +126,8 @@ Inode::Open(int mode, OpenFileCookie* cookie)
 		fOpenState = state;
 		cookie->fOpenState = state;
 		locker.Unlock();
-
-		RevalidateFileCache();
+		if (fDelegation == NULL)
+			RevalidateFileCache();
 	} else {
 		fOpenState->AcquireReference();
 		cookie->fOpenState = fOpenState;
@@ -138,7 +139,7 @@ Inode::Open(int mode, OpenFileCookie* cookie)
 			if (oldMode == O_RDONLY)
 				RecallReadDelegation();
 
-			status_t result = OpenFile(fOpenState, O_RDWR, &data);
+			status_t result = OpenFile(fOpenState, newMode, &data);
 			if (result != B_OK) {
 				locker.Lock();
 				ReleaseOpenState();
@@ -197,7 +198,7 @@ Inode::Close(OpenFileCookie* cookie)
 
 	int mode = cookie->fMode & O_RWMASK;
 	if (mode == O_RDWR || mode == O_WRONLY)
-		SyncAndCommit();
+		SyncAndCommit(false, cookie);
 
 	MutexLocker _(fStateLock);
 	ReleaseOpenState();
@@ -323,6 +324,8 @@ Inode::ReadDirect(OpenStateCookie* cookie, off_t pos, void* buffer,
 
 	status_t result;
 	OpenState* state = cookie != NULL ? cookie->fOpenState : fOpenState;
+	ReadLocker delegationLocker(fDelegationLock);
+	ASSERT(state->fDelegation == fDelegation);
 	while (size < *_length && !*eof) {
 		uint32 len = *_length - size;
 		result = ReadFile(cookie, state, pos + size, &len,
@@ -363,7 +366,7 @@ status_t
 Inode::WriteDirect(OpenStateCookie* cookie, off_t pos, const void* _buffer,
 	size_t* _length)
 {
-	ASSERT(cookie != NULL || fOpenState != NULL);
+	ASSERT_WITH_DUMP(cookie != NULL || fOpenState != NULL, this);
 	ASSERT(_buffer != NULL);
 	ASSERT(_length != NULL);
 
@@ -385,6 +388,8 @@ Inode::WriteDirect(OpenStateCookie* cookie, off_t pos, const void* _buffer,
 		fWriteDirty = true;
 	}
 
+	ReadLocker delegationLocker(fDelegationLock);
+	ASSERT(state->fDelegation == fDelegation);
 	while (size < *_length) {
 		uint32 len = *_length - size;
 		status_t result = WriteFile(cookie, state, pos + size, &len,
@@ -436,7 +441,8 @@ Inode::Write(OpenFileCookie* cookie, off_t pos, const void* _buffer,
 			// We will let the server zero out the rest of the hole.
 			fMaxFileSize = pos;
 			size_t pageOffset = pos % B_PAGE_SIZE;
-			file_cache_write(fFileCache, cookie, pos - pageOffset, NULL, &pageOffset);
+			if (pageOffset != 0)
+				file_cache_write(fFileCache, cookie, pos - pageOffset, NULL, &pageOffset);
 		}
 		fMaxFileSize = fileSize;
 		fMetaCache.GrowFile(fMaxFileSize);
@@ -444,7 +450,7 @@ Inode::Write(OpenFileCookie* cookie, off_t pos, const void* _buffer,
 
 	if ((cookie->fMode & O_NOCACHE) != 0) {
 		WriteDirect(cookie, pos, _buffer, _length);
-		Commit();
+		Commit(cookie->fUid, cookie->fGid);
 	}
 
 	return file_cache_write(fFileCache, cookie, pos, _buffer, _length);
@@ -452,13 +458,13 @@ Inode::Write(OpenFileCookie* cookie, off_t pos, const void* _buffer,
 
 
 status_t
-Inode::Commit()
+Inode::Commit(uid_t uid, gid_t gid)
 {
 	if (!fWriteDirty)
 		return B_OK;
 
 	WriteLocker _(fWriteLock);
-	status_t result = CommitWrites();
+	status_t result = CommitWrites(fDelegation != NULL, uid, gid);
 	if (result != B_OK)
 		return result;
 	fWriteDirty = false;
diff --git a/src/add-ons/kernel/file_systems/nfs4/NFS4Inode.cpp b/src/add-ons/kernel/file_systems/nfs4/NFS4Inode.cpp
index c954da1df2..03939444dc 100644
--- a/src/add-ons/kernel/file_systems/nfs4/NFS4Inode.cpp
+++ b/src/add-ons/kernel/file_systems/nfs4/NFS4Inode.cpp
@@ -61,20 +61,38 @@ NFS4Inode::GetChangeInfo(uint64* change, bool attrDir)
 
 
 status_t
-NFS4Inode::CommitWrites()
+NFS4Inode::CommitWrites(bool unlockBetweenAttempts, uid_t uid, gid_t gid)
 {
 	uint32 attempt = 0;
+	uint32 retryLimit = 0;
+	bool hard = true;
+	if (fFileSystem != NULL) {
+		retryLimit = fFileSystem->GetConfiguration().fRetryLimit;
+		hard = fFileSystem->GetConfiguration().fHard;
+	}
+
 	do {
 		RPC::Server* serv = fFileSystem->Server();
-		Request request(serv, fFileSystem, geteuid(), getegid());
+		Request request(serv, fFileSystem, uid, gid, unlockBetweenAttempts);
 		RequestBuilder& req = request.Builder();
 
 		req.PutFH(fInfo.fHandle);
 		req.Commit(0, 0);
 
 		status_t result = request.Send();
-		if (result != B_OK)
-			return result;
+		if (result != B_OK) {
+			if (unlockBetweenAttempts && (hard || attempt < retryLimit)) {
+				// The server won't reply to a commit request while a delegation recall is in
+				// progress. To avoid a deadlock, we respond to a failure to reply by releasing
+				// fWriteLock, allowing the CallbackServer thread to proceed with CallbackRecall()
+				// if it is blocked, and trying the commit request again.
+				static_cast<Inode*>(this)->UnlockAndRelockWriteLock();
+				++attempt;
+				continue;
+			} else {
+				return result;
+			}
+		}
 
 		ReplyInterpreter& reply = request.Reply();
 
@@ -318,22 +336,40 @@ NFS4Inode::GetStat(AttrValue** values, uint32* count, OpenAttrCookie* cookie)
 
 
 status_t
-NFS4Inode::WriteStat(OpenState* state, AttrValue* attrs, uint32 attrCount)
+NFS4Inode::WriteStat(OpenState* state, Delegation* delegation, AttrValue* attrs, uint32 attrCount)
 {
 	ASSERT(attrs != NULL);
 
 	uint32 attempt = 0;
+	Inode* inode = delegation != NULL ? delegation->GetInode() : NULL;
+
+	bool useDelegationStateID = true;
 	do {
 		RPC::Server* serv = fFileSystem->Server();
 		Request request(serv, fFileSystem, geteuid(), getegid());
 		RequestBuilder& req = request.Builder();
 
+		uint32 stateID[3];
+		memset(stateID, 0, sizeof(stateID));
+		uint32 stateSeq = 0;
+
 		if (state != NULL) {
+			if (state->fDelegation != NULL && useDelegationStateID) {
+				delegation = state->fDelegation;
+				delegation->GetStateIDandSeq(stateID, stateSeq);
+			} else {
+				memcpy(stateID, state->fStateID, sizeof(stateID));
+				stateSeq = state->fStateSeq;
+			}
 			req.PutFH(state->fInfo.fHandle);
-			req.SetAttr(state->fStateID, state->fStateSeq, attrs, attrCount);
+			req.SetAttr(stateID, stateSeq, attrs, attrCount);
 		} else {
+			if (delegation != NULL && useDelegationStateID) {
+				// We might have a delegation regardless of whether the file is open.
+				delegation->GetStateIDandSeq(stateID, stateSeq);
+			}
 			req.PutFH(fInfo.fHandle);
-			req.SetAttr(NULL, 0, attrs, attrCount);
+			req.SetAttr(stateID, stateSeq, attrs, attrCount);
 		}
 
 		status_t result = request.Send();
@@ -342,8 +378,19 @@ NFS4Inode::WriteStat(OpenState* state, AttrValue* attrs, uint32 attrCount)
 
 		ReplyInterpreter& reply = request.Reply();
 
-		if (HandleErrors(attempt, reply.NFS4Error(), serv))
+		if (HandleErrors(attempt, reply.NFS4Error(), serv, NULL, state)) {
+			if (reply.NFS4Error() == NFS4ERR_DELAY && delegation != NULL) {
+				delegation->GetInode()->UnlockAndRelockStateLocks();
+				if (inode != NULL) {
+					// The OpenState and Delegation pointers might be invalid now.
+					state = inode->GetOpenState();
+					delegation = inode->GetDelegation();
+				}
+			} else if (reply.NFS4Error() == NFS4ERR_OPENMODE && state->fDelegation != NULL) {
+				useDelegationStateID = false;
+			}
 			continue;
+		}
 
 		reply.PutFH();
 		result = reply.SetAttr();
@@ -726,13 +773,24 @@ NFS4Inode::ReadFile(OpenStateCookie* cookie, OpenState* state, uint64 position,
 	ASSERT(eof != NULL);
 
 	uint32 attempt = 0;
+	bool useDelegationStateID = true;
 	do {
 		RPC::Server* serv = fFileSystem->Server();
 		Request request(serv, fFileSystem, geteuid(), getegid());
 		RequestBuilder& req = request.Builder();
 
+		uint32 stateID[3];
+		memset(stateID, 0, sizeof(stateID));
+		uint32 stateSeq = 0;
+		if (state->fDelegation != NULL && useDelegationStateID) {
+			state->fDelegation->GetStateIDandSeq(stateID, stateSeq);
+		} else {
+			memcpy(stateID, state->fStateID, sizeof(stateID));
+			stateSeq = state->fStateSeq;
+		}
+
 		req.PutFH(state->fInfo.fHandle);
-		req.Read(state->fStateID, state->fStateSeq, position, *length);
+		req.Read(stateID, stateSeq, position, *length);
 
 		status_t result = request.Send(cookie);
 		if (result != B_OK)
@@ -740,8 +798,13 @@ NFS4Inode::ReadFile(OpenStateCookie* cookie, OpenState* state, uint64 position,
 
 		ReplyInterpreter& reply = request.Reply();
 
-		if (HandleErrors(attempt, reply.NFS4Error(), serv, cookie, state))
+		if (HandleErrors(attempt, reply.NFS4Error(), serv, cookie, state)) {
+			if (reply.NFS4Error() == NFS4ERR_DELAY && state->fDelegation != NULL)
+				state->fDelegation->GetInode()->UnlockAndRelockStateLocks();
+			else if (reply.NFS4Error() == NFS4ERR_OPENMODE && state->fDelegation != NULL)
+				useDelegationStateID = false;
 			continue;
+		}
 
 		reply.PutFH();
 		result = reply.Read(buffer, length, eof);
@@ -762,14 +825,25 @@ NFS4Inode::WriteFile(OpenStateCookie* cookie, OpenState* state, uint64 position,
 	ASSERT(buffer != NULL);
 
 	uint32 attempt = 0;
+	bool useDelegationStateID = true;
 	do {
 		RPC::Server* serv = fFileSystem->Server();
 		Request request(serv, fFileSystem, state->fUid, state->fGid);
 		RequestBuilder& req = request.Builder();
 
+		uint32 stateID[3];
+		memset(stateID, 0, sizeof(stateID));
+		uint32 stateSeq = 0;
+		if (state->fDelegation != NULL && useDelegationStateID) {
+			state->fDelegation->GetStateIDandSeq(stateID, stateSeq);
+		} else {
+			memcpy(stateID, state->fStateID, sizeof(stateID));
+			stateSeq = state->fStateSeq;
+		}
+
 		req.PutFH(state->fInfo.fHandle);
 
-		req.Write(state->fStateID, state->fStateSeq, buffer, position, *length,
+		req.Write(stateID, stateSeq, buffer, position, *length,
 			commit);
 
 		status_t result = request.Send(cookie);
@@ -778,8 +852,13 @@ NFS4Inode::WriteFile(OpenStateCookie* cookie, OpenState* state, uint64 position,
 
 		ReplyInterpreter& reply = request.Reply();
 
-		if (HandleErrors(attempt, reply.NFS4Error(), serv, cookie, state))
+		if (HandleErrors(attempt, reply.NFS4Error(), serv, cookie, state)) {
+			if (reply.NFS4Error() == NFS4ERR_DELAY && state->fDelegation != NULL)
+				state->fDelegation->GetInode()->UnlockAndRelockStateLocks();
+			else if (reply.NFS4Error() == NFS4ERR_OPENMODE && state->fDelegation != NULL)
+				useDelegationStateID = false;
 			continue;
+		}
 
 		reply.PutFH();
 
diff --git a/src/add-ons/kernel/file_systems/nfs4/NFS4Inode.h b/src/add-ons/kernel/file_systems/nfs4/NFS4Inode.h
index 4aff6886c9..3f7134c0d9 100644
--- a/src/add-ons/kernel/file_systems/nfs4/NFS4Inode.h
+++ b/src/add-ons/kernel/file_systems/nfs4/NFS4Inode.h
@@ -28,7 +28,7 @@ public:
 protected:
 			status_t	Access(uint32* allowed);
 
-			status_t	CommitWrites();
+			status_t	CommitWrites(bool unlockBetweenAttempts, uid_t uid, gid_t gid);
 
 			status_t	LookUp(const char* name, uint64* change, uint64* fileID,
 							FileHandle* handle, bool parent = false);
@@ -43,8 +43,8 @@ protected:
 
 			status_t	GetStat(AttrValue** values, uint32* count,
 							OpenAttrCookie* attr = NULL);
-			status_t	WriteStat(OpenState* state, AttrValue* attrs,
-							uint32 attrCount);
+			status_t	WriteStat(OpenState* state, Delegation* delegation,
+							AttrValue* attrs, uint32 attrCount);
 
 			status_t	CreateFile(const char* name, int mode, int perms,
 							OpenState* state, ChangeInfo* changeInfo,
diff --git a/src/add-ons/kernel/file_systems/nfs4/NFS4Object.cpp b/src/add-ons/kernel/file_systems/nfs4/NFS4Object.cpp
index eaa6f6bbee..aecc9852a9 100644
--- a/src/add-ons/kernel/file_systems/nfs4/NFS4Object.cpp
+++ b/src/add-ons/kernel/file_systems/nfs4/NFS4Object.cpp
@@ -184,6 +184,12 @@ NFS4Object::HandleErrors(uint32& attempt, uint32 nfs4Error, RPC::Server* server,
 			}
 			return false;
 
+		// delegation might have just been recalled, or is about to be recalled
+		case NFS4ERR_OPENMODE:
+			if (state->fDelegation != NULL)
+				return true;
+			return false;
+
 		default:
 			return false;
 	}
diff --git a/src/add-ons/kernel/file_systems/nfs4/NFS4Server.cpp b/src/add-ons/kernel/file_systems/nfs4/NFS4Server.cpp
index c0ac6f2366..2099155061 100644
--- a/src/add-ons/kernel/file_systems/nfs4/NFS4Server.cpp
+++ b/src/add-ons/kernel/file_systems/nfs4/NFS4Server.cpp
@@ -348,6 +348,11 @@ NFS4Server::CallbackRecall(RequestInterpreter* request, ReplyBuilder* reply)
 	DelegationRecallArgs* args = new(std::nothrow) DelegationRecallArgs;
 	args->fDelegation = delegation;
 	args->fTruncate = truncate;
+
+	// If an IORequest job is needed, we should enqueue it before enqueueing
+	// the DelegationRecall job.
+	delegation->GetInode()->PrepareDelegationRecall(truncate);
+
 	gWorkQueue->EnqueueJob(DelegationRecall, args);
 
 	reply->Recall(B_OK);
diff --git a/src/add-ons/kernel/file_systems/nfs4/Request.cpp b/src/add-ons/kernel/file_systems/nfs4/Request.cpp
index 20631bb155..643dbc2b8b 100644
--- a/src/add-ons/kernel/file_systems/nfs4/Request.cpp
+++ b/src/add-ons/kernel/file_systems/nfs4/Request.cpp
@@ -48,6 +48,11 @@ Request::_SendUDP(Cookie* cookie)
 		hard = fFileSystem->GetConfiguration().fHard;
 	}
 
+	if (fSingleAttempt) {
+		requestTimeout /= 10;
+		retryLimit = 0;
+	}
+
 	result = fServer->WaitCall(rpc, requestTimeout);
 	if (result != B_OK) {
 		int attempts = 1;
@@ -107,6 +112,11 @@ Request::_SendTCP(Cookie* cookie)
 		hard = fFileSystem->GetConfiguration().fHard;
 	}
 
+	if (fSingleAttempt) {
+		requestTimeout /= 10;
+		retryLimit = 0;
+	}
+
 	do {
 		result = fServer->SendCallAsync(fBuilder.Request(), &rpl, &rpc);
 		if (result == B_NO_MEMORY)
diff --git a/src/add-ons/kernel/file_systems/nfs4/Request.h b/src/add-ons/kernel/file_systems/nfs4/Request.h
index 85e8593778..566cbc4850 100644
--- a/src/add-ons/kernel/file_systems/nfs4/Request.h
+++ b/src/add-ons/kernel/file_systems/nfs4/Request.h
@@ -21,7 +21,7 @@ class Request {
 public:
 	inline						Request(RPC::Server* server,
 									FileSystem* fileSystem,
-									uid_t uid, gid_t gid);
+									uid_t uid, gid_t gid, bool singleAttempt = false);
 
 	inline	RequestBuilder&		Builder();
 	inline	ReplyInterpreter&	Reply();
@@ -38,15 +38,19 @@ private:
 
 			RequestBuilder		fBuilder;
 			ReplyInterpreter	fReply;
+
+			bool				fSingleAttempt;
 };
 
 
 inline
-Request::Request(RPC::Server* server, FileSystem* fileSystem, uid_t uid, gid_t gid)
+Request::Request(RPC::Server* server, FileSystem* fileSystem, uid_t uid, gid_t gid,
+	bool singleAttempt)
 	:
 	fServer(server),
 	fFileSystem(fileSystem),
-	fBuilder(uid, gid)
+	fBuilder(uid, gid),
+	fSingleAttempt(singleAttempt)
 {
 	ASSERT(server != NULL);
 }
diff --git a/src/add-ons/kernel/file_systems/nfs4/WorkQueue.cpp b/src/add-ons/kernel/file_systems/nfs4/WorkQueue.cpp
index d023d736ea..59e5fb16f0 100644
--- a/src/add-ons/kernel/file_systems/nfs4/WorkQueue.cpp
+++ b/src/add-ons/kernel/file_systems/nfs4/WorkQueue.cpp
@@ -186,7 +186,24 @@ void
 WorkQueue::JobRecall(DelegationRecallArgs* args)
 {
 	ASSERT(args != NULL);
-	args->fDelegation->GetInode()->RecallDelegation(args->fTruncate);
+
+	Inode* inode = args->fDelegation->GetInode();
+	if (inode->AIOIncomplete()) {
+		// Re-queue and try again later.
+		WorkQueueEntry* entry = new(std::nothrow) WorkQueueEntry;
+		if (entry == NULL)
+			return;
+
+		entry->fType = DelegationRecall;
+		entry->fArguments = args;
+
+		// The queue is already locked.
+		fQueue.InsertAfter(fQueue.Tail(), entry);
+	} else {
+		args->fDelegation->GetInode()->RecallDelegationAsync(args->fTruncate);
+	}
+
+	return;
 }
 
 
diff --git a/src/add-ons/kernel/file_systems/nfs4/kernel_interface.cpp b/src/add-ons/kernel/file_systems/nfs4/kernel_interface.cpp
index 36a7fe50ec..e36fc19cb8 100644
--- a/src/add-ons/kernel/file_systems/nfs4/kernel_interface.cpp
+++ b/src/add-ons/kernel/file_systems/nfs4/kernel_interface.cpp
@@ -349,7 +349,7 @@ nfs4_remove_vnode(fs_volume* volume, fs_vnode* vnode, bool reenter)
 
 	// Unless the file was deleted by someone else, verify that all known names have been
 	// unlinked.
-	if (node->IsStale() == false) {
+	if (node != NULL && node->IsStale() == false) {
 		FileInfo fileInfo;
 		ASSERT(fs->InoIdMap()->GetFileInfo(&fileInfo, vti->ID()) == B_ENTRY_NOT_FOUND);
 	}