Commit 383ba719 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Fix a deadlock with lazy umount 



We can't allow rpc callback functions like task->tk_ops->rpc_call_prepare()
and task->tk_ops->rpc_call_done() to call mntput() in any way, since
that will cause a deadlock when the call to rpc_shutdown_client() attempts
to wait on 'task' to complete.

We can avoid the above deadlock by moving calls to mntput to
task->tk_ops->rpc_release() callback, since at that time the task will be
marked as completed, and so rpc_shutdown_client won't attempt to wait on
it.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 4b5621f6

fs/nfs/direct.c

+3 −2
Original line number Diff line number Diff line
@@ -323,7 +323,7 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq, 
		data->inode = inode;

		data->cred = msg.rpc_cred;

		data->args.fh = NFS_FH(inode);

		data->args.context = ctx;

		data->args.context = get_nfs_open_context(ctx);

		data->args.offset = pos;

		data->args.pgbase = pgbase;

		data->args.pages = data->pagevec;
@@ -546,6 +546,7 @@ static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq) 
	data->args.fh = NFS_FH(data->inode);

	data->args.offset = 0;

	data->args.count = 0;

	data->args.context = get_nfs_open_context(dreq->ctx);

	data->res.count = 0;

	data->res.fattr = &data->fattr;

	data->res.verf = &data->verf;
@@ -728,7 +729,7 @@ static ssize_t nfs_direct_write_schedule_segment(struct nfs_direct_req *dreq, 
		data->inode = inode;

		data->cred = msg.rpc_cred;

		data->args.fh = NFS_FH(inode);

		data->args.context = ctx;

		data->args.context = get_nfs_open_context(ctx);

		data->args.offset = pos;

		data->args.pgbase = pgbase;

		data->args.pages = data->pagevec;

fs/nfs/inode.c

+5 −1
Original line number Diff line number Diff line
@@ -521,8 +521,12 @@ struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx) 


static void __put_nfs_open_context(struct nfs_open_context *ctx, int wait)

{

	struct inode *inode = ctx->path.dentry->d_inode;

	struct inode *inode;



	if (ctx == NULL)

		return;



	inode = ctx->path.dentry->d_inode;

	if (!atomic_dec_and_lock(&ctx->count, &inode->i_lock))

		return;

	list_del(&ctx->list);

fs/nfs/read.c

+5 −2
Original line number Diff line number Diff line
@@ -73,7 +73,10 @@ static void nfs_readdata_free(struct nfs_read_data *rdata) 


void nfs_readdata_release(void *data)

{

        nfs_readdata_free(data);

	struct nfs_read_data *rdata = data;



	put_nfs_open_context(rdata->args.context);

	nfs_readdata_free(rdata);

}



static
@@ -186,7 +189,7 @@ static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data, 
	data->args.pgbase = req->wb_pgbase + offset;

	data->args.pages  = data->pagevec;

	data->args.count  = count;

	data->args.context = req->wb_context;

	data->args.context = get_nfs_open_context(req->wb_context);



	data->res.fattr   = &data->fattr;

	data->res.count   = count;

fs/nfs/write.c

+10 −3
Original line number Diff line number Diff line
@@ -105,8 +105,11 @@ static void nfs_writedata_free(struct nfs_write_data *wdata) 
	call_rcu_bh(&wdata->task.u.tk_rcu, nfs_writedata_rcu_free);

}



void nfs_writedata_release(void *wdata)

void nfs_writedata_release(void *data)

{

	struct nfs_write_data *wdata = data;



	put_nfs_open_context(wdata->args.context);

	nfs_writedata_free(wdata);

}
@@ -816,7 +819,7 @@ static void nfs_write_rpcsetup(struct nfs_page *req, 
	data->args.pgbase = req->wb_pgbase + offset;

	data->args.pages  = data->pagevec;

	data->args.count  = count;

	data->args.context = req->wb_context;

	data->args.context = get_nfs_open_context(req->wb_context);

	data->args.stable  = NFS_UNSTABLE;

	if (how & FLUSH_STABLE) {

		data->args.stable = NFS_DATA_SYNC;
@@ -1153,8 +1156,11 @@ int nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data) 




#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)

void nfs_commit_release(void *wdata)

void nfs_commit_release(void *data)

{

	struct nfs_write_data *wdata = data;



	put_nfs_open_context(wdata->args.context);

	nfs_commit_free(wdata);

}
@@ -1197,6 +1203,7 @@ static void nfs_commit_rpcsetup(struct list_head *head, 
	/* Note: we always request a commit of the entire inode */

	data->args.offset = 0;

	data->args.count  = 0;

	data->args.context = get_nfs_open_context(first->wb_context);

	data->res.count   = 0;

	data->res.fattr   = &data->fattr;

	data->res.verf    = &data->verf;

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