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Commit 65b62a29 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4: Ensure delegation recall and byte range lock removal don't conflict 



Add a mutex to the struct nfs4_state_owner to ensure that delegation
recall doesn't conflict with byte range lock removal.

Note that we nest the new mutex _outside_ the state manager reclaim
protection (nfsi->rwsem) in order to avoid deadlocks.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 37380e42

fs/nfs/delegation.c

+6 −1
Original line number Original line Diff line number Diff line
@@ -71,8 +71,10 @@ static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_ 
	int status = 0;

	int status = 0;





	if (inode->i_flock == NULL)

	if (inode->i_flock == NULL)

		goto out;

		return 0;





	if (inode->i_flock == NULL)

		goto out;

	/* Protect inode->i_flock using the file locks lock */

	/* Protect inode->i_flock using the file locks lock */

	lock_flocks();

	lock_flocks();

	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {

	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
@@ -113,12 +115,15 @@ static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *s 
		get_nfs_open_context(ctx);

		get_nfs_open_context(ctx);

		spin_unlock(&inode->i_lock);

		spin_unlock(&inode->i_lock);

		sp = state->owner;

		sp = state->owner;

		/* Block nfs4_proc_unlck */

		mutex_lock(&sp->so_delegreturn_mutex);

		seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);

		seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);

		err = nfs4_open_delegation_recall(ctx, state, stateid);

		err = nfs4_open_delegation_recall(ctx, state, stateid);

		if (!err)

		if (!err)

			err = nfs_delegation_claim_locks(ctx, state);

			err = nfs_delegation_claim_locks(ctx, state);

		if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))

		if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))

			err = -EAGAIN;

			err = -EAGAIN;

		mutex_unlock(&sp->so_delegreturn_mutex);

		put_nfs_open_context(ctx);

		put_nfs_open_context(ctx);

		if (err != 0)

		if (err != 0)

			return err;

			return err;

fs/nfs/nfs4_fs.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -93,6 +93,7 @@ struct nfs4_state_owner { 
	struct list_head     so_states;

	struct list_head     so_states;

	struct nfs_seqid_counter so_seqid;

	struct nfs_seqid_counter so_seqid;

	seqcount_t	     so_reclaim_seqcount;

	seqcount_t	     so_reclaim_seqcount;

	struct mutex	     so_delegreturn_mutex;

};

};





enum {

enum {

fs/nfs/nfs4proc.c

+8 −1
Original line number Original line Diff line number Diff line
@@ -4485,7 +4485,9 @@ static struct rpc_task *nfs4_do_unlck(struct file_lock *fl, 




static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *request)

static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *request)

{

{

	struct nfs_inode *nfsi = NFS_I(state->inode);

	struct inode *inode = state->inode;

	struct nfs4_state_owner *sp = state->owner;

	struct nfs_inode *nfsi = NFS_I(inode);

	struct nfs_seqid *seqid;

	struct nfs_seqid *seqid;

	struct nfs4_lock_state *lsp;

	struct nfs4_lock_state *lsp;

	struct rpc_task *task;

	struct rpc_task *task;
@@ -4495,12 +4497,17 @@ static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock * 
	status = nfs4_set_lock_state(state, request);

	status = nfs4_set_lock_state(state, request);

	/* Unlock _before_ we do the RPC call */

	/* Unlock _before_ we do the RPC call */

	request->fl_flags |= FL_EXISTS;

	request->fl_flags |= FL_EXISTS;

	/* Exclude nfs_delegation_claim_locks() */

	mutex_lock(&sp->so_delegreturn_mutex);

	/* Exclude nfs4_reclaim_open_stateid() - note nesting! */

	down_read(&nfsi->rwsem);

	down_read(&nfsi->rwsem);

	if (do_vfs_lock(request->fl_file, request) == -ENOENT) {

	if (do_vfs_lock(request->fl_file, request) == -ENOENT) {

		up_read(&nfsi->rwsem);

		up_read(&nfsi->rwsem);

		mutex_unlock(&sp->so_delegreturn_mutex);

		goto out;

		goto out;

	}

	}

	up_read(&nfsi->rwsem);

	up_read(&nfsi->rwsem);

	mutex_unlock(&sp->so_delegreturn_mutex);

	if (status != 0)

	if (status != 0)

		goto out;

		goto out;

	/* Is this a delegated lock? */

	/* Is this a delegated lock? */

fs/nfs/nfs4state.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -519,6 +519,7 @@ nfs4_alloc_state_owner(struct nfs_server *server, 
	atomic_set(&sp->so_count, 1);

	atomic_set(&sp->so_count, 1);

	INIT_LIST_HEAD(&sp->so_lru);

	INIT_LIST_HEAD(&sp->so_lru);

	seqcount_init(&sp->so_reclaim_seqcount);

	seqcount_init(&sp->so_reclaim_seqcount);

	mutex_init(&sp->so_delegreturn_mutex);

	return sp;

	return sp;

}

}