Linux-2.6.12-rc2v2.6.12-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 000000000000..a0042fb58634
--- /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");
+}