Commit a8881f5a authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: O_DIRECT async IO may lose context 



The struct nfs_direct_req currently keeps a pointer to the file descriptor
without referencing it. This may cause problems if the parent process is
killed.

The nfs_open_context should normally have all the information that we're
currently using the filp for, and unlike fput(), is safe to release from
an rpciod process context.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent fad61490

fs/nfs/direct.c

+12 −18
Original line number Diff line number Diff line
@@ -71,7 +71,7 @@ struct nfs_direct_req { 
	/* I/O parameters */

	struct list_head	list,		/* nfs_read/write_data structs */

				rewrite_list;	/* saved nfs_write_data structs */

	struct file *		filp;		/* file descriptor */

	struct nfs_open_context	*ctx;		/* file open context info */

	struct kiocb *		iocb;		/* controlling i/o request */

	wait_queue_head_t	wait;		/* wait for i/o completion */

	struct inode *		inode;		/* target file of i/o */
@@ -176,6 +176,7 @@ static inline struct nfs_direct_req *nfs_direct_req_alloc(void) 
	INIT_LIST_HEAD(&dreq->list);

	INIT_LIST_HEAD(&dreq->rewrite_list);

	dreq->iocb = NULL;

	dreq->ctx = NULL;

	spin_lock_init(&dreq->lock);

	dreq->outstanding = 0;

	dreq->count = 0;
@@ -188,6 +189,9 @@ static inline struct nfs_direct_req *nfs_direct_req_alloc(void) 
static void nfs_direct_req_release(struct kref *kref)

{

	struct nfs_direct_req *dreq = container_of(kref, struct nfs_direct_req, kref);



	if (dreq->ctx != NULL)

		put_nfs_open_context(dreq->ctx);

	kmem_cache_free(nfs_direct_cachep, dreq);

}
@@ -235,7 +239,6 @@ static void nfs_direct_complete(struct nfs_direct_req *dreq) 
	} else

		wake_up(&dreq->wait);



	iput(dreq->inode);

	kref_put(&dreq->kref, nfs_direct_req_release);

}
@@ -317,10 +320,8 @@ static const struct rpc_call_ops nfs_read_direct_ops = { 
 */

static void nfs_direct_read_schedule(struct nfs_direct_req *dreq)

{

	struct file *file = dreq->filp;

	struct inode *inode = file->f_mapping->host;

	struct nfs_open_context *ctx = (struct nfs_open_context *)

							file->private_data;

	struct nfs_open_context *ctx = dreq->ctx;

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

	struct list_head *list = &dreq->list;

	struct page **pages = dreq->pages;

	size_t count = dreq->user_count;
@@ -396,9 +397,8 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, unsigned long user_addr, size 
	dreq->pos = pos;

	dreq->pages = pages;

	dreq->npages = nr_pages;

	igrab(inode);

	dreq->inode = inode;

	dreq->filp = iocb->ki_filp;

	dreq->ctx = get_nfs_open_context((struct nfs_open_context *)iocb->ki_filp->private_data);

	if (!is_sync_kiocb(iocb))

		dreq->iocb = iocb;
@@ -462,14 +462,11 @@ static const struct rpc_call_ops nfs_commit_direct_ops = { 


static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq)

{

	struct file *file = dreq->filp;

	struct nfs_open_context *ctx = (struct nfs_open_context *)

							file->private_data;

	struct nfs_write_data *data = dreq->commit_data;

	struct rpc_task *task = &data->task;



	data->inode = dreq->inode;

	data->cred = ctx->cred;

	data->cred = dreq->ctx->cred;



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

	data->args.offset = dreq->pos;
@@ -641,10 +638,8 @@ static const struct rpc_call_ops nfs_write_direct_ops = { 
 */

static void nfs_direct_write_schedule(struct nfs_direct_req *dreq, int sync)

{

	struct file *file = dreq->filp;

	struct inode *inode = file->f_mapping->host;

	struct nfs_open_context *ctx = (struct nfs_open_context *)

							file->private_data;

	struct nfs_open_context *ctx = dreq->ctx;

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

	struct list_head *list = &dreq->list;

	struct page **pages = dreq->pages;

	size_t count = dreq->user_count;
@@ -725,9 +720,8 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, unsigned long user_addr, siz 
	dreq->pos = pos;

	dreq->pages = pages;

	dreq->npages = nr_pages;

	igrab(inode);

	dreq->inode = inode;

	dreq->filp = iocb->ki_filp;

	dreq->ctx = get_nfs_open_context((struct nfs_open_context *)iocb->ki_filp->private_data);

	if (!is_sync_kiocb(iocb))

		dreq->iocb = iocb;

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