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Commit 584aa810 authored by Fred Isaman's avatar Fred Isaman Committed by Trond Myklebust
Browse files

NFS: rewrite directio read to use async coalesce code 



This also has the advantage that it allows directio to use pnfs.

Signed-off-by: default avatarFred Isaman <iisaman@netapp.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 1825a0d0

fs/nfs/direct.c

+123 −132
Original line number Diff line number Diff line
@@ -124,22 +124,6 @@ ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_ 
	return -EINVAL;

}



static void nfs_direct_dirty_pages(struct page **pages, unsigned int pgbase, size_t count)

{

	unsigned int npages;

	unsigned int i;



	if (count == 0)

		return;

	pages += (pgbase >> PAGE_SHIFT);

	npages = (count + (pgbase & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;

	for (i = 0; i < npages; i++) {

		struct page *page = pages[i];

		if (!PageCompound(page))

			set_page_dirty(page);

	}

}



static void nfs_direct_release_pages(struct page **pages, unsigned int npages)

{

	unsigned int i;
@@ -226,58 +210,92 @@ static void nfs_direct_complete(struct nfs_direct_req *dreq) 
	nfs_direct_req_release(dreq);

}



/*

 * We must hold a reference to all the pages in this direct read request

 * until the RPCs complete.  This could be long *after* we are woken up in

 * nfs_direct_wait (for instance, if someone hits ^C on a slow server).

 */

static void nfs_direct_read_result(struct rpc_task *task, void *calldata)

void nfs_direct_readpage_release(struct nfs_page *req)

{

	struct nfs_read_data *data = calldata;



	nfs_readpage_result(task, data);

	dprintk("NFS: direct read done (%s/%lld %d@%lld)\n",

		req->wb_context->dentry->d_inode->i_sb->s_id,

		(long long)NFS_FILEID(req->wb_context->dentry->d_inode),

		req->wb_bytes,

		(long long)req_offset(req));

	nfs_release_request(req);

}



static void nfs_direct_read_release(void *calldata)

static void nfs_direct_read_completion(struct nfs_pgio_header *hdr)

{

	unsigned long bytes = 0;

	struct nfs_direct_req *dreq = hdr->dreq;



	struct nfs_read_data *data = calldata;

	struct nfs_direct_req *dreq = (struct nfs_direct_req *)data->header->req;

	int status = data->task.tk_status;

	if (test_bit(NFS_IOHDR_REDO, &hdr->flags))

		goto out_put;



	spin_lock(&dreq->lock);

	if (unlikely(status < 0)) {

		dreq->error = status;

	if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && (hdr->good_bytes == 0))

		dreq->error = hdr->error;

	else

		dreq->count += hdr->good_bytes;

	spin_unlock(&dreq->lock);



	if (!test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {

		while (!list_empty(&hdr->pages)) {

			struct nfs_page *req = nfs_list_entry(hdr->pages.next);

			struct page *page = req->wb_page;



			if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {

				if (bytes > hdr->good_bytes)

					zero_user(page, 0, PAGE_SIZE);

				else if (hdr->good_bytes - bytes < PAGE_SIZE)

					zero_user_segment(page,

						hdr->good_bytes & ~PAGE_MASK,

						PAGE_SIZE);

			}

			bytes += req->wb_bytes;

			nfs_list_remove_request(req);

			nfs_direct_readpage_release(req);

			if (!PageCompound(page))

				set_page_dirty(page);

			page_cache_release(page);

		}

	} else {

		dreq->count += data->res.count;

		spin_unlock(&dreq->lock);

		nfs_direct_dirty_pages(data->pages.pagevec,

				data->args.pgbase,

				data->res.count);

		while (!list_empty(&hdr->pages)) {

			struct nfs_page *req = nfs_list_entry(hdr->pages.next);



			if (bytes < hdr->good_bytes)

				if (!PageCompound(req->wb_page))

					set_page_dirty(req->wb_page);

			bytes += req->wb_bytes;

			page_cache_release(req->wb_page);

			nfs_list_remove_request(req);

			nfs_direct_readpage_release(req);

		}

	nfs_direct_release_pages(data->pages.pagevec, data->pages.npages);



	}

out_put:

	if (put_dreq(dreq))

		nfs_direct_complete(dreq);

	nfs_readdata_release(data);

	hdr->release(hdr);

}



static const struct rpc_call_ops nfs_read_direct_ops = {

	.rpc_call_prepare = nfs_read_prepare,

	.rpc_call_done = nfs_direct_read_result,

	.rpc_release = nfs_direct_read_release,

};



static void nfs_direct_readhdr_release(struct nfs_read_header *rhdr)

static void nfs_sync_pgio_error(struct list_head *head)

{

	struct nfs_read_data *data = &rhdr->rpc_data;

	struct nfs_page *req;



	if (data->pages.pagevec != data->pages.page_array)

		kfree(data->pages.pagevec);

	nfs_readhdr_free(&rhdr->header);

	while (!list_empty(head)) {

		req = nfs_list_entry(head->next);

		nfs_list_remove_request(req);

		nfs_release_request(req);

	}

}



static void nfs_direct_pgio_init(struct nfs_pgio_header *hdr)

{

	get_dreq(hdr->dreq);

}



static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = {

	.error_cleanup = nfs_sync_pgio_error,

	.init_hdr = nfs_direct_pgio_init,

	.completion = nfs_direct_read_completion,

};



/*

 * For each rsize'd chunk of the user's buffer, dispatch an NFS READ

 * operation.  If nfs_readdata_alloc() or get_user_pages() fails,
@@ -285,118 +303,85 @@ static void nfs_direct_readhdr_release(struct nfs_read_header *rhdr) 
 * handled automatically by nfs_direct_read_result().  Otherwise, if

 * no requests have been sent, just return an error.

 */

static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,

static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *desc,

						const struct iovec *iov,

						loff_t pos)

{

	struct nfs_direct_req *dreq = desc->pg_dreq;

	struct nfs_open_context *ctx = dreq->ctx;

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

	unsigned long user_addr = (unsigned long)iov->iov_base;

	size_t count = iov->iov_len;

	size_t rsize = NFS_SERVER(inode)->rsize;

	struct rpc_task *task;

	struct rpc_message msg = {

		.rpc_cred = ctx->cred,

	};

	struct rpc_task_setup task_setup_data = {

		.rpc_client = NFS_CLIENT(inode),

		.rpc_message = &msg,

		.callback_ops = &nfs_read_direct_ops,

		.workqueue = nfsiod_workqueue,

		.flags = RPC_TASK_ASYNC,

	};

	unsigned int pgbase;

	int result;

	ssize_t started = 0;

	struct page **pagevec = NULL;

	unsigned int npages;



	do {

		struct nfs_read_header *rhdr;

		struct nfs_read_data *data;

		struct nfs_page_array *pages;

		size_t bytes;

		int i;



		pgbase = user_addr & ~PAGE_MASK;

		bytes = min(rsize,count);

		bytes = min(max(rsize, PAGE_SIZE), count);



		result = -ENOMEM;

		rhdr = nfs_readhdr_alloc();

		if (unlikely(!rhdr))

			break;

		data = nfs_readdata_alloc(&rhdr->header, nfs_page_array_len(pgbase, bytes));

		if (!data) {

			nfs_readhdr_free(&rhdr->header);

		npages = nfs_page_array_len(pgbase, bytes);

		if (!pagevec)

			pagevec = kmalloc(npages * sizeof(struct page *),

					  GFP_KERNEL);

		if (!pagevec)

			break;

		}

		data->header = &rhdr->header;

		atomic_inc(&data->header->refcnt);

		pages = &data->pages;



		down_read(&current->mm->mmap_sem);

		result = get_user_pages(current, current->mm, user_addr,

					pages->npages, 1, 0, pages->pagevec, NULL);

					npages, 1, 0, pagevec, NULL);

		up_read(&current->mm->mmap_sem);

		if (result < 0) {

			nfs_direct_readhdr_release(rhdr);

		if (result < 0)

			break;

		}

		if ((unsigned)result < pages->npages) {

		if ((unsigned)result < npages) {

			bytes = result * PAGE_SIZE;

			if (bytes <= pgbase) {

				nfs_direct_release_pages(pages->pagevec, result);

				nfs_direct_readhdr_release(rhdr);

				nfs_direct_release_pages(pagevec, result);

				break;

			}

			bytes -= pgbase;

			pages->npages = result;

			npages = result;

		}



		get_dreq(dreq);



		rhdr->header.req = (struct nfs_page *) dreq;

		rhdr->header.inode = inode;

		rhdr->header.cred = msg.rpc_cred;

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

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

		data->args.lock_context = dreq->l_ctx;

		data->args.offset = pos;

		data->args.pgbase = pgbase;

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

		data->args.count = bytes;

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

		data->res.eof = 0;

		data->res.count = bytes;

		nfs_fattr_init(&data->fattr);

		msg.rpc_argp = &data->args;

		msg.rpc_resp = &data->res;



		task_setup_data.task = &data->task;

		task_setup_data.callback_data = data;

		NFS_PROTO(inode)->read_setup(data, &msg);



		task = rpc_run_task(&task_setup_data);

		if (IS_ERR(task))

		for (i = 0; i < npages; i++) {

			struct nfs_page *req;

			unsigned int req_len = min(bytes, PAGE_SIZE - pgbase);

			/* XXX do we need to do the eof zeroing found in async_filler? */

			req = nfs_create_request(dreq->ctx, dreq->inode,

						 pagevec[i],

						 pgbase, req_len);

			if (IS_ERR(req)) {

				nfs_direct_release_pages(pagevec + i,

							 npages - i);

				result = PTR_ERR(req);

				break;



		dprintk("NFS: %5u initiated direct read call "

			"(req %s/%Ld, %zu bytes @ offset %Lu)\n",

				task->tk_pid,

				inode->i_sb->s_id,

				(long long)NFS_FILEID(inode),

				bytes,

				(unsigned long long)data->args.offset);

		rpc_put_task(task);



		started += bytes;

		user_addr += bytes;

		pos += bytes;

		/* FIXME: Remove this unnecessary math from final patch */

		pgbase += bytes;

		pgbase &= ~PAGE_MASK;

		BUG_ON(pgbase != (user_addr & ~PAGE_MASK));



		count -= bytes;

			}

			req->wb_index = pos >> PAGE_SHIFT;

			req->wb_offset = pos & ~PAGE_MASK;

			if (!nfs_pageio_add_request(desc, req)) {

				result = desc->pg_error;

				nfs_release_request(req);

				nfs_direct_release_pages(pagevec + i,

							 npages - i);

				break;

			}

			pgbase = 0;

			bytes -= req_len;

			started += req_len;

			user_addr += req_len;

			pos += req_len;

			count -= req_len;

		}

	} while (count != 0);



	kfree(pagevec);



	if (started)

		return started;

	return result < 0 ? (ssize_t) result : -EFAULT;
@@ -407,15 +392,19 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, 
					      unsigned long nr_segs,

					      loff_t pos)

{

	struct nfs_pageio_descriptor desc;

	ssize_t result = -EINVAL;

	size_t requested_bytes = 0;

	unsigned long seg;



	nfs_pageio_init_read(&desc, dreq->inode,

			     &nfs_direct_read_completion_ops);

	get_dreq(dreq);

	desc.pg_dreq = dreq;



	for (seg = 0; seg < nr_segs; seg++) {

		const struct iovec *vec = &iov[seg];

		result = nfs_direct_read_schedule_segment(dreq, vec, pos);

		result = nfs_direct_read_schedule_segment(&desc, vec, pos);

		if (result < 0)

			break;

		requested_bytes += result;
@@ -424,6 +413,8 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, 
		pos += vec->iov_len;

	}



	nfs_pageio_complete(&desc);



	/*

	 * If no bytes were started, return the error, and let the

	 * generic layer handle the completion.

fs/nfs/internal.h

+3 −2
Original line number Diff line number Diff line
@@ -304,8 +304,9 @@ struct nfs_pgio_completion_ops; 
/* read.c */

extern struct nfs_read_header *nfs_readhdr_alloc(void);

extern void nfs_readhdr_free(struct nfs_pgio_header *hdr);

extern struct nfs_read_data *nfs_readdata_alloc(struct nfs_pgio_header *hdr,

						unsigned int pagecount);

extern void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,

			struct inode *inode,

			const struct nfs_pgio_completion_ops *compl_ops);

extern int nfs_initiate_read(struct rpc_clnt *clnt,

			     struct nfs_read_data *data,

			     const struct rpc_call_ops *call_ops);

fs/nfs/pagelist.c

+4 −3
Original line number Diff line number Diff line
@@ -48,8 +48,11 @@ void nfs_pgheader_init(struct nfs_pageio_descriptor *desc, 
	hdr->cred = hdr->req->wb_context->cred;

	hdr->io_start = req_offset(hdr->req);

	hdr->good_bytes = desc->pg_count;

	hdr->dreq = desc->pg_dreq;

	hdr->release = release;

	hdr->completion_ops = desc->pg_completion_ops;

	if (hdr->completion_ops->init_hdr)

		hdr->completion_ops->init_hdr(hdr);

}



void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
@@ -116,9 +119,6 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode, 
	req->wb_page    = page;

	req->wb_index	= page->index;

	page_cache_get(page);

	BUG_ON(PagePrivate(page));

	BUG_ON(!PageLocked(page));

	BUG_ON(page->mapping->host != inode);

	req->wb_offset  = offset;

	req->wb_pgbase	= offset;

	req->wb_bytes   = count;
@@ -257,6 +257,7 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc, 
	desc->pg_ioflags = io_flags;

	desc->pg_error = 0;

	desc->pg_lseg = NULL;

	desc->pg_dreq = NULL;

}



/**

fs/nfs/read.c

+5 −5
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ struct nfs_read_header *nfs_readhdr_alloc() 
	return rhdr;

}



struct nfs_read_data *nfs_readdata_alloc(struct nfs_pgio_header *hdr,

static struct nfs_read_data *nfs_readdata_alloc(struct nfs_pgio_header *hdr,

						unsigned int pagecount)

{

	struct nfs_read_data *data, *prealloc;
@@ -123,7 +123,7 @@ void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio) 
}

EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);



static void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,

void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,

			  struct inode *inode,

			  const struct nfs_pgio_completion_ops *compl_ops)

{

include/linux/nfs_page.h

+1 −0
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ struct nfs_pageio_descriptor { 
	const struct rpc_call_ops *pg_rpc_callops;

	const struct nfs_pgio_completion_ops *pg_completion_ops;

	struct pnfs_layout_segment *pg_lseg;

	struct nfs_direct_req	*pg_dreq;

};



#define NFS_WBACK_BUSY(req)	(test_bit(PG_BUSY,&(req)->wb_flags))