Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 618 insertions, 0 deletions

diff --git a/fs/nfs/read.c b/fs/nfs/read.c
new file mode 100644
index 0000000..a0042fb
--- /dev/null
+++ b/fs/nfs/read.c
@@ -0,0 +1,618 @@
+/*
+ * linux/fs/nfs/read.c
+ *
+ * Block I/O for NFS
+ *
+ * Partial copy of Linus' read cache modifications to fs/nfs/file.c
+ * modified for async RPC by okir@monad.swb.de
+ *
+ * We do an ugly hack here in order to return proper error codes to the
+ * user program when a read request failed: since generic_file_read
+ * only checks the return value of inode->i_op->readpage() which is always 0
+ * for async RPC, we set the error bit of the page to 1 when an error occurs,
+ * and make nfs_readpage transmit requests synchronously when encountering this.
+ * This is only a small problem, though, since we now retry all operations
+ * within the RPC code when root squashing is suspected.
+ */
+
+#include <linux/config.h>
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fcntl.h>
+#include <linux/stat.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_page.h>
+#include <linux/smp_lock.h>
+
+#include <asm/system.h>
+
+#define NFSDBG_FACILITY		NFSDBG_PAGECACHE
+
+static int nfs_pagein_one(struct list_head *, struct inode *);
+static void nfs_readpage_result_partial(struct nfs_read_data *, int);
+static void nfs_readpage_result_full(struct nfs_read_data *, int);
+
+static kmem_cache_t *nfs_rdata_cachep;
+mempool_t *nfs_rdata_mempool;
+
+#define MIN_POOL_READ	(32)
+
+void nfs_readdata_release(struct rpc_task *task)
+{
+        struct nfs_read_data   *data = (struct nfs_read_data *)task->tk_calldata;
+        nfs_readdata_free(data);
+}
+
+static
+unsigned int nfs_page_length(struct inode *inode, struct page *page)
+{
+	loff_t i_size = i_size_read(inode);
+	unsigned long idx;
+
+	if (i_size <= 0)
+		return 0;
+	idx = (i_size - 1) >> PAGE_CACHE_SHIFT;
+	if (page->index > idx)
+		return 0;
+	if (page->index != idx)
+		return PAGE_CACHE_SIZE;
+	return 1 + ((i_size - 1) & (PAGE_CACHE_SIZE - 1));
+}
+
+static
+int nfs_return_empty_page(struct page *page)
+{
+	memclear_highpage_flush(page, 0, PAGE_CACHE_SIZE);
+	SetPageUptodate(page);
+	unlock_page(page);
+	return 0;
+}
+
+/*
+ * Read a page synchronously.
+ */
+static int nfs_readpage_sync(struct nfs_open_context *ctx, struct inode *inode,
+		struct page *page)
+{
+	unsigned int	rsize = NFS_SERVER(inode)->rsize;
+	unsigned int	count = PAGE_CACHE_SIZE;
+	int		result;
+	struct nfs_read_data *rdata;
+
+	rdata = nfs_readdata_alloc();
+	if (!rdata)
+		return -ENOMEM;
+
+	memset(rdata, 0, sizeof(*rdata));
+	rdata->flags = (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);
+	rdata->cred = ctx->cred;
+	rdata->inode = inode;
+	INIT_LIST_HEAD(&rdata->pages);
+	rdata->args.fh = NFS_FH(inode);
+	rdata->args.context = ctx;
+	rdata->args.pages = &page;
+	rdata->args.pgbase = 0UL;
+	rdata->args.count = rsize;
+	rdata->res.fattr = &rdata->fattr;
+
+	dprintk("NFS: nfs_readpage_sync(%p)\n", page);
+
+	/*
+	 * This works now because the socket layer never tries to DMA
+	 * into this buffer directly.
+	 */
+	do {
+		if (count < rsize)
+			rdata->args.count = count;
+		rdata->res.count = rdata->args.count;
+		rdata->args.offset = page_offset(page) + rdata->args.pgbase;
+
+		dprintk("NFS: nfs_proc_read(%s, (%s/%Ld), %Lu, %u)\n",
+			NFS_SERVER(inode)->hostname,
+			inode->i_sb->s_id,
+			(long long)NFS_FILEID(inode),
+			(unsigned long long)rdata->args.pgbase,
+			rdata->args.count);
+
+		lock_kernel();
+		result = NFS_PROTO(inode)->read(rdata);
+		unlock_kernel();
+
+		/*
+		 * Even if we had a partial success we can't mark the page
+		 * cache valid.
+		 */
+		if (result < 0) {
+			if (result == -EISDIR)
+				result = -EINVAL;
+			goto io_error;
+		}
+		count -= result;
+		rdata->args.pgbase += result;
+		/* Note: result == 0 should only happen if we're caching
+		 * a write that extends the file and punches a hole.
+		 */
+		if (rdata->res.eof != 0 || result == 0)
+			break;
+	} while (count);
+	NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME;
+
+	if (count)
+		memclear_highpage_flush(page, rdata->args.pgbase, count);
+	SetPageUptodate(page);
+	if (PageError(page))
+		ClearPageError(page);
+	result = 0;
+
+io_error:
+	unlock_page(page);
+	nfs_readdata_free(rdata);
+	return result;
+}
+
+static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
+		struct page *page)
+{
+	LIST_HEAD(one_request);
+	struct nfs_page	*new;
+	unsigned int len;
+
+	len = nfs_page_length(inode, page);
+	if (len == 0)
+		return nfs_return_empty_page(page);
+	new = nfs_create_request(ctx, inode, page, 0, len);
+	if (IS_ERR(new)) {
+		unlock_page(page);
+		return PTR_ERR(new);
+	}
+	if (len < PAGE_CACHE_SIZE)
+		memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len);
+
+	nfs_lock_request(new);
+	nfs_list_add_request(new, &one_request);
+	nfs_pagein_one(&one_request, inode);
+	return 0;
+}
+
+static void nfs_readpage_release(struct nfs_page *req)
+{
+	unlock_page(req->wb_page);
+
+	nfs_clear_request(req);
+	nfs_release_request(req);
+	nfs_unlock_request(req);
+
+	dprintk("NFS: read done (%s/%Ld %d@%Ld)\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));
+}
+
+/*
+ * Set up the NFS read request struct
+ */
+static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
+		unsigned int count, unsigned int offset)
+{
+	struct inode		*inode;
+
+	data->req	  = req;
+	data->inode	  = inode = req->wb_context->dentry->d_inode;
+	data->cred	  = req->wb_context->cred;
+
+	data->args.fh     = NFS_FH(inode);
+	data->args.offset = req_offset(req) + offset;
+	data->args.pgbase = req->wb_pgbase + offset;
+	data->args.pages  = data->pagevec;
+	data->args.count  = count;
+	data->args.context = req->wb_context;
+
+	data->res.fattr   = &data->fattr;
+	data->res.count   = count;
+	data->res.eof     = 0;
+
+	NFS_PROTO(inode)->read_setup(data);
+
+	data->task.tk_cookie = (unsigned long)inode;
+	data->task.tk_calldata = data;
+	/* Release requests */
+	data->task.tk_release = nfs_readdata_release;
+
+	dprintk("NFS: %4d initiated read call (req %s/%Ld, %u bytes @ offset %Lu)\n",
+			data->task.tk_pid,
+			inode->i_sb->s_id,
+			(long long)NFS_FILEID(inode),
+			count,
+			(unsigned long long)data->args.offset);
+}
+
+static void
+nfs_async_read_error(struct list_head *head)
+{
+	struct nfs_page	*req;
+
+	while (!list_empty(head)) {
+		req = nfs_list_entry(head->next);
+		nfs_list_remove_request(req);
+		SetPageError(req->wb_page);
+		nfs_readpage_release(req);
+	}
+}
+
+/*
+ * Start an async read operation
+ */
+static void nfs_execute_read(struct nfs_read_data *data)
+{
+	struct rpc_clnt *clnt = NFS_CLIENT(data->inode);
+	sigset_t oldset;
+
+	rpc_clnt_sigmask(clnt, &oldset);
+	lock_kernel();
+	rpc_execute(&data->task);
+	unlock_kernel();
+	rpc_clnt_sigunmask(clnt, &oldset);
+}
+
+/*
+ * Generate multiple requests to fill a single page.
+ *
+ * We optimize to reduce the number of read operations on the wire.  If we
+ * detect that we're reading a page, or an area of a page, that is past the
+ * end of file, we do not generate NFS read operations but just clear the
+ * parts of the page that would have come back zero from the server anyway.
+ *
+ * We rely on the cached value of i_size to make this determination; another
+ * client can fill pages on the server past our cached end-of-file, but we
+ * won't see the new data until our attribute cache is updated.  This is more
+ * or less conventional NFS client behavior.
+ */
+static int nfs_pagein_multi(struct list_head *head, struct inode *inode)
+{
+	struct nfs_page *req = nfs_list_entry(head->next);
+	struct page *page = req->wb_page;
+	struct nfs_read_data *data;
+	unsigned int rsize = NFS_SERVER(inode)->rsize;
+	unsigned int nbytes, offset;
+	int requests = 0;
+	LIST_HEAD(list);
+
+	nfs_list_remove_request(req);
+
+	nbytes = req->wb_bytes;
+	for(;;) {
+		data = nfs_readdata_alloc();
+		if (!data)
+			goto out_bad;
+		INIT_LIST_HEAD(&data->pages);
+		list_add(&data->pages, &list);
+		requests++;
+		if (nbytes <= rsize)
+			break;
+		nbytes -= rsize;
+	}
+	atomic_set(&req->wb_complete, requests);
+
+	ClearPageError(page);
+	offset = 0;
+	nbytes = req->wb_bytes;
+	do {
+		data = list_entry(list.next, struct nfs_read_data, pages);
+		list_del_init(&data->pages);
+
+		data->pagevec[0] = page;
+		data->complete = nfs_readpage_result_partial;
+
+		if (nbytes > rsize) {
+			nfs_read_rpcsetup(req, data, rsize, offset);
+			offset += rsize;
+			nbytes -= rsize;
+		} else {
+			nfs_read_rpcsetup(req, data, nbytes, offset);
+			nbytes = 0;
+		}
+		nfs_execute_read(data);
+	} while (nbytes != 0);
+
+	return 0;
+
+out_bad:
+	while (!list_empty(&list)) {
+		data = list_entry(list.next, struct nfs_read_data, pages);
+		list_del(&data->pages);
+		nfs_readdata_free(data);
+	}
+	SetPageError(page);
+	nfs_readpage_release(req);
+	return -ENOMEM;
+}
+
+static int nfs_pagein_one(struct list_head *head, struct inode *inode)
+{
+	struct nfs_page		*req;
+	struct page		**pages;
+	struct nfs_read_data	*data;
+	unsigned int		count;
+
+	if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE)
+		return nfs_pagein_multi(head, inode);
+
+	data = nfs_readdata_alloc();
+	if (!data)
+		goto out_bad;
+
+	INIT_LIST_HEAD(&data->pages);
+	pages = data->pagevec;
+	count = 0;
+	while (!list_empty(head)) {
+		req = nfs_list_entry(head->next);
+		nfs_list_remove_request(req);
+		nfs_list_add_request(req, &data->pages);
+		ClearPageError(req->wb_page);
+		*pages++ = req->wb_page;
+		count += req->wb_bytes;
+	}
+	req = nfs_list_entry(data->pages.next);
+
+	data->complete = nfs_readpage_result_full;
+	nfs_read_rpcsetup(req, data, count, 0);
+
+	nfs_execute_read(data);
+	return 0;
+out_bad:
+	nfs_async_read_error(head);
+	return -ENOMEM;
+}
+
+static int
+nfs_pagein_list(struct list_head *head, int rpages)
+{
+	LIST_HEAD(one_request);
+	struct nfs_page		*req;
+	int			error = 0;
+	unsigned int		pages = 0;
+
+	while (!list_empty(head)) {
+		pages += nfs_coalesce_requests(head, &one_request, rpages);
+		req = nfs_list_entry(one_request.next);
+		error = nfs_pagein_one(&one_request, req->wb_context->dentry->d_inode);
+		if (error < 0)
+			break;
+	}
+	if (error >= 0)
+		return pages;
+
+	nfs_async_read_error(head);
+	return error;
+}
+
+/*
+ * Handle a read reply that fills part of a page.
+ */
+static void nfs_readpage_result_partial(struct nfs_read_data *data, int status)
+{
+	struct nfs_page *req = data->req;
+	struct page *page = req->wb_page;
+ 
+	if (status >= 0) {
+		unsigned int request = data->args.count;
+		unsigned int result = data->res.count;
+
+		if (result < request) {
+			memclear_highpage_flush(page,
+						data->args.pgbase + result,
+						request - result);
+		}
+	} else
+		SetPageError(page);
+
+	if (atomic_dec_and_test(&req->wb_complete)) {
+		if (!PageError(page))
+			SetPageUptodate(page);
+		nfs_readpage_release(req);
+	}
+}
+
+/*
+ * This is the callback from RPC telling us whether a reply was
+ * received or some error occurred (timeout or socket shutdown).
+ */
+static void nfs_readpage_result_full(struct nfs_read_data *data, int status)
+{
+	unsigned int count = data->res.count;
+
+	while (!list_empty(&data->pages)) {
+		struct nfs_page *req = nfs_list_entry(data->pages.next);
+		struct page *page = req->wb_page;
+		nfs_list_remove_request(req);
+
+		if (status >= 0) {
+			if (count < PAGE_CACHE_SIZE) {
+				if (count < req->wb_bytes)
+					memclear_highpage_flush(page,
+							req->wb_pgbase + count,
+							req->wb_bytes - count);
+				count = 0;
+			} else
+				count -= PAGE_CACHE_SIZE;
+			SetPageUptodate(page);
+		} else
+			SetPageError(page);
+		nfs_readpage_release(req);
+	}
+}
+
+/*
+ * This is the callback from RPC telling us whether a reply was
+ * received or some error occurred (timeout or socket shutdown).
+ */
+void nfs_readpage_result(struct rpc_task *task)
+{
+	struct nfs_read_data *data = (struct nfs_read_data *)task->tk_calldata;
+	struct nfs_readargs *argp = &data->args;
+	struct nfs_readres *resp = &data->res;
+	int status = task->tk_status;
+
+	dprintk("NFS: %4d nfs_readpage_result, (status %d)\n",
+		task->tk_pid, status);
+
+	/* Is this a short read? */
+	if (task->tk_status >= 0 && resp->count < argp->count && !resp->eof) {
+		/* Has the server at least made some progress? */
+		if (resp->count != 0) {
+			/* Yes, so retry the read at the end of the data */
+			argp->offset += resp->count;
+			argp->pgbase += resp->count;
+			argp->count -= resp->count;
+			rpc_restart_call(task);
+			return;
+		}
+		task->tk_status = -EIO;
+	}
+	NFS_FLAGS(data->inode) |= NFS_INO_INVALID_ATIME;
+	data->complete(data, status);
+}
+
+/*
+ * Read a page over NFS.
+ * We read the page synchronously in the following case:
+ *  -	The error flag is set for this page. This happens only when a
+ *	previous async read operation failed.
+ */
+int nfs_readpage(struct file *file, struct page *page)
+{
+	struct nfs_open_context *ctx;
+	struct inode *inode = page->mapping->host;
+	int		error;
+
+	dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
+		page, PAGE_CACHE_SIZE, page->index);
+	/*
+	 * Try to flush any pending writes to the file..
+	 *
+	 * NOTE! Because we own the page lock, there cannot
+	 * be any new pending writes generated at this point
+	 * for this page (other pages can be written to).
+	 */
+	error = nfs_wb_page(inode, page);
+	if (error)
+		goto out_error;
+
+	if (file == NULL) {
+		ctx = nfs_find_open_context(inode, FMODE_READ);
+		if (ctx == NULL)
+			return -EBADF;
+	} else
+		ctx = get_nfs_open_context((struct nfs_open_context *)
+				file->private_data);
+	if (!IS_SYNC(inode)) {
+		error = nfs_readpage_async(ctx, inode, page);
+		goto out;
+	}
+
+	error = nfs_readpage_sync(ctx, inode, page);
+	if (error < 0 && IS_SWAPFILE(inode))
+		printk("Aiee.. nfs swap-in of page failed!\n");
+out:
+	put_nfs_open_context(ctx);
+	return error;
+
+out_error:
+	unlock_page(page);
+	return error;
+}
+
+struct nfs_readdesc {
+	struct list_head *head;
+	struct nfs_open_context *ctx;
+};
+
+static int
+readpage_async_filler(void *data, struct page *page)
+{
+	struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
+	struct inode *inode = page->mapping->host;
+	struct nfs_page *new;
+	unsigned int len;
+
+	nfs_wb_page(inode, page);
+	len = nfs_page_length(inode, page);
+	if (len == 0)
+		return nfs_return_empty_page(page);
+	new = nfs_create_request(desc->ctx, inode, page, 0, len);
+	if (IS_ERR(new)) {
+			SetPageError(page);
+			unlock_page(page);
+			return PTR_ERR(new);
+	}
+	if (len < PAGE_CACHE_SIZE)
+		memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len);
+	nfs_lock_request(new);
+	nfs_list_add_request(new, desc->head);
+	return 0;
+}
+
+int nfs_readpages(struct file *filp, struct address_space *mapping,
+		struct list_head *pages, unsigned nr_pages)
+{
+	LIST_HEAD(head);
+	struct nfs_readdesc desc = {
+		.head		= &head,
+	};
+	struct inode *inode = mapping->host;
+	struct nfs_server *server = NFS_SERVER(inode);
+	int ret;
+
+	dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
+			inode->i_sb->s_id,
+			(long long)NFS_FILEID(inode),
+			nr_pages);
+
+	if (filp == NULL) {
+		desc.ctx = nfs_find_open_context(inode, FMODE_READ);
+		if (desc.ctx == NULL)
+			return -EBADF;
+	} else
+		desc.ctx = get_nfs_open_context((struct nfs_open_context *)
+				filp->private_data);
+	ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
+	if (!list_empty(&head)) {
+		int err = nfs_pagein_list(&head, server->rpages);
+		if (!ret)
+			ret = err;
+	}
+	put_nfs_open_context(desc.ctx);
+	return ret;
+}
+
+int nfs_init_readpagecache(void)
+{
+	nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
+					     sizeof(struct nfs_read_data),
+					     0, SLAB_HWCACHE_ALIGN,
+					     NULL, NULL);
+	if (nfs_rdata_cachep == NULL)
+		return -ENOMEM;
+
+	nfs_rdata_mempool = mempool_create(MIN_POOL_READ,
+					   mempool_alloc_slab,
+					   mempool_free_slab,
+					   nfs_rdata_cachep);
+	if (nfs_rdata_mempool == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void nfs_destroy_readpagecache(void)
+{
+	mempool_destroy(nfs_rdata_mempool);
+	if (kmem_cache_destroy(nfs_rdata_cachep))
+		printk(KERN_INFO "nfs_read_data: not all structures were freed\n");
+}