diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/nfs/read.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/nfs/read.c | 699 |
1 files changed, 699 insertions, 0 deletions
diff --git a/ANDROID_3.4.5/fs/nfs/read.c b/ANDROID_3.4.5/fs/nfs/read.c new file mode 100644 index 00000000..0a4be28c --- /dev/null +++ b/ANDROID_3.4.5/fs/nfs/read.c @@ -0,0 +1,699 @@ +/* + * 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 + */ + +#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/module.h> + +#include "pnfs.h" + +#include "nfs4_fs.h" +#include "internal.h" +#include "iostat.h" +#include "fscache.h" + +#define NFSDBG_FACILITY NFSDBG_PAGECACHE + +static const struct nfs_pageio_ops nfs_pageio_read_ops; +static const struct rpc_call_ops nfs_read_partial_ops; +static const struct rpc_call_ops nfs_read_full_ops; + +static struct kmem_cache *nfs_rdata_cachep; + +struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount) +{ + struct nfs_read_data *p; + + p = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL); + if (p) { + INIT_LIST_HEAD(&p->pages); + p->npages = pagecount; + if (pagecount <= ARRAY_SIZE(p->page_array)) + p->pagevec = p->page_array; + else { + p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL); + if (!p->pagevec) { + kmem_cache_free(nfs_rdata_cachep, p); + p = NULL; + } + } + } + return p; +} + +void nfs_readdata_free(struct nfs_read_data *p) +{ + if (p && (p->pagevec != &p->page_array[0])) + kfree(p->pagevec); + kmem_cache_free(nfs_rdata_cachep, p); +} + +void nfs_readdata_release(struct nfs_read_data *rdata) +{ + put_nfs_open_context(rdata->args.context); + nfs_readdata_free(rdata); +} + +static +int nfs_return_empty_page(struct page *page) +{ + zero_user(page, 0, PAGE_CACHE_SIZE); + SetPageUptodate(page); + unlock_page(page); + return 0; +} + +static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data) +{ + unsigned int remainder = data->args.count - data->res.count; + unsigned int base = data->args.pgbase + data->res.count; + unsigned int pglen; + struct page **pages; + + if (data->res.eof == 0 || remainder == 0) + return; + /* + * Note: "remainder" can never be negative, since we check for + * this in the XDR code. + */ + pages = &data->args.pages[base >> PAGE_CACHE_SHIFT]; + base &= ~PAGE_CACHE_MASK; + pglen = PAGE_CACHE_SIZE - base; + for (;;) { + if (remainder <= pglen) { + zero_user(*pages, base, remainder); + break; + } + zero_user(*pages, base, pglen); + pages++; + remainder -= pglen; + pglen = PAGE_CACHE_SIZE; + base = 0; + } +} + +void nfs_pageio_init_read_mds(struct nfs_pageio_descriptor *pgio, + struct inode *inode) +{ + nfs_pageio_init(pgio, inode, &nfs_pageio_read_ops, + NFS_SERVER(inode)->rsize, 0); +} + +void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio) +{ + pgio->pg_ops = &nfs_pageio_read_ops; + pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize; +} +EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds); + +static void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, + struct inode *inode) +{ + if (!pnfs_pageio_init_read(pgio, inode)) + nfs_pageio_init_read_mds(pgio, inode); +} + +int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, + struct page *page) +{ + struct nfs_page *new; + unsigned int len; + struct nfs_pageio_descriptor pgio; + + len = nfs_page_length(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) + zero_user_segment(page, len, PAGE_CACHE_SIZE); + + nfs_pageio_init_read(&pgio, inode); + nfs_pageio_add_request(&pgio, new); + nfs_pageio_complete(&pgio); + return 0; +} + +static void nfs_readpage_release(struct nfs_page *req) +{ + struct inode *d_inode = req->wb_context->dentry->d_inode; + + if (PageUptodate(req->wb_page)) + nfs_readpage_to_fscache(d_inode, req->wb_page, 0); + + unlock_page(req->wb_page); + + 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)); + nfs_release_request(req); +} + +int nfs_initiate_read(struct nfs_read_data *data, struct rpc_clnt *clnt, + const struct rpc_call_ops *call_ops) +{ + struct inode *inode = data->inode; + int swap_flags = IS_SWAPFILE(inode) ? NFS_RPC_SWAPFLAGS : 0; + struct rpc_task *task; + struct rpc_message msg = { + .rpc_argp = &data->args, + .rpc_resp = &data->res, + .rpc_cred = data->cred, + }; + struct rpc_task_setup task_setup_data = { + .task = &data->task, + .rpc_client = clnt, + .rpc_message = &msg, + .callback_ops = call_ops, + .callback_data = data, + .workqueue = nfsiod_workqueue, + .flags = RPC_TASK_ASYNC | swap_flags, + }; + + /* Set up the initial task struct. */ + NFS_PROTO(inode)->read_setup(data, &msg); + + dprintk("NFS: %5u initiated read call (req %s/%lld, %u bytes @ " + "offset %llu)\n", + data->task.tk_pid, + inode->i_sb->s_id, + (long long)NFS_FILEID(inode), + data->args.count, + (unsigned long long)data->args.offset); + + task = rpc_run_task(&task_setup_data); + if (IS_ERR(task)) + return PTR_ERR(task); + rpc_put_task(task); + return 0; +} +EXPORT_SYMBOL_GPL(nfs_initiate_read); + +/* + * 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 = req->wb_context->dentry->d_inode; + + data->req = req; + data->inode = 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 = get_nfs_open_context(req->wb_context); + data->args.lock_context = req->wb_lock_context; + + data->res.fattr = &data->fattr; + data->res.count = count; + data->res.eof = 0; + nfs_fattr_init(&data->fattr); +} + +static int nfs_do_read(struct nfs_read_data *data, + const struct rpc_call_ops *call_ops) +{ + struct inode *inode = data->args.context->dentry->d_inode; + + return nfs_initiate_read(data, NFS_CLIENT(inode), call_ops); +} + +static int +nfs_do_multiple_reads(struct list_head *head, + const struct rpc_call_ops *call_ops) +{ + struct nfs_read_data *data; + int ret = 0; + + while (!list_empty(head)) { + int ret2; + + data = list_entry(head->next, struct nfs_read_data, list); + list_del_init(&data->list); + + ret2 = nfs_do_read(data, call_ops); + if (ret == 0) + ret = ret2; + } + return ret; +} + +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); + nfs_readpage_release(req); + } +} + +/* + * 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 nfs_pageio_descriptor *desc, struct list_head *res) +{ + struct nfs_page *req = nfs_list_entry(desc->pg_list.next); + struct page *page = req->wb_page; + struct nfs_read_data *data; + size_t rsize = desc->pg_bsize, nbytes; + unsigned int offset; + int requests = 0; + int ret = 0; + + nfs_list_remove_request(req); + + offset = 0; + nbytes = desc->pg_count; + do { + size_t len = min(nbytes,rsize); + + data = nfs_readdata_alloc(1); + if (!data) + goto out_bad; + data->pagevec[0] = page; + nfs_read_rpcsetup(req, data, len, offset); + list_add(&data->list, res); + requests++; + nbytes -= len; + offset += len; + } while(nbytes != 0); + atomic_set(&req->wb_complete, requests); + desc->pg_rpc_callops = &nfs_read_partial_ops; + return ret; +out_bad: + while (!list_empty(res)) { + data = list_entry(res->next, struct nfs_read_data, list); + list_del(&data->list); + nfs_readdata_release(data); + } + nfs_readpage_release(req); + return -ENOMEM; +} + +static int nfs_pagein_one(struct nfs_pageio_descriptor *desc, struct list_head *res) +{ + struct nfs_page *req; + struct page **pages; + struct nfs_read_data *data; + struct list_head *head = &desc->pg_list; + int ret = 0; + + data = nfs_readdata_alloc(nfs_page_array_len(desc->pg_base, + desc->pg_count)); + if (!data) { + nfs_async_read_error(head); + ret = -ENOMEM; + goto out; + } + + pages = data->pagevec; + while (!list_empty(head)) { + req = nfs_list_entry(head->next); + nfs_list_remove_request(req); + nfs_list_add_request(req, &data->pages); + *pages++ = req->wb_page; + } + req = nfs_list_entry(data->pages.next); + + nfs_read_rpcsetup(req, data, desc->pg_count, 0); + list_add(&data->list, res); + desc->pg_rpc_callops = &nfs_read_full_ops; +out: + return ret; +} + +int nfs_generic_pagein(struct nfs_pageio_descriptor *desc, struct list_head *head) +{ + if (desc->pg_bsize < PAGE_CACHE_SIZE) + return nfs_pagein_multi(desc, head); + return nfs_pagein_one(desc, head); +} + +static int nfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc) +{ + LIST_HEAD(head); + int ret; + + ret = nfs_generic_pagein(desc, &head); + if (ret == 0) + ret = nfs_do_multiple_reads(&head, desc->pg_rpc_callops); + return ret; +} + +static const struct nfs_pageio_ops nfs_pageio_read_ops = { + .pg_test = nfs_generic_pg_test, + .pg_doio = nfs_generic_pg_readpages, +}; + +/* + * This is the callback from RPC telling us whether a reply was + * received or some error occurred (timeout or socket shutdown). + */ +int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data) +{ + int status; + + dprintk("NFS: %s: %5u, (status %d)\n", __func__, task->tk_pid, + task->tk_status); + + status = NFS_PROTO(data->inode)->read_done(task, data); + if (status != 0) + return status; + + nfs_add_stats(data->inode, NFSIOS_SERVERREADBYTES, data->res.count); + + if (task->tk_status == -ESTALE) { + set_bit(NFS_INO_STALE, &NFS_I(data->inode)->flags); + nfs_mark_for_revalidate(data->inode); + } + return 0; +} + +static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data) +{ + struct nfs_readargs *argp = &data->args; + struct nfs_readres *resp = &data->res; + + if (resp->eof || resp->count == argp->count) + return; + + /* This is a short read! */ + nfs_inc_stats(data->inode, NFSIOS_SHORTREAD); + /* Has the server at least made some progress? */ + if (resp->count == 0) + return; + + /* Yes, so retry the read at the end of the data */ + data->mds_offset += resp->count; + argp->offset += resp->count; + argp->pgbase += resp->count; + argp->count -= resp->count; + rpc_restart_call_prepare(task); +} + +/* + * Handle a read reply that fills part of a page. + */ +static void nfs_readpage_result_partial(struct rpc_task *task, void *calldata) +{ + struct nfs_read_data *data = calldata; + + if (nfs_readpage_result(task, data) != 0) + return; + if (task->tk_status < 0) + return; + + nfs_readpage_truncate_uninitialised_page(data); + nfs_readpage_retry(task, data); +} + +static void nfs_readpage_release_partial(void *calldata) +{ + struct nfs_read_data *data = calldata; + struct nfs_page *req = data->req; + struct page *page = req->wb_page; + int status = data->task.tk_status; + + if (status < 0) + set_bit(PG_PARTIAL_READ_FAILED, &req->wb_flags); + + if (atomic_dec_and_test(&req->wb_complete)) { + if (!test_bit(PG_PARTIAL_READ_FAILED, &req->wb_flags)) + SetPageUptodate(page); + nfs_readpage_release(req); + } + nfs_readdata_release(calldata); +} + +void nfs_read_prepare(struct rpc_task *task, void *calldata) +{ + struct nfs_read_data *data = calldata; + NFS_PROTO(data->inode)->read_rpc_prepare(task, data); +} + +static const struct rpc_call_ops nfs_read_partial_ops = { + .rpc_call_prepare = nfs_read_prepare, + .rpc_call_done = nfs_readpage_result_partial, + .rpc_release = nfs_readpage_release_partial, +}; + +static void nfs_readpage_set_pages_uptodate(struct nfs_read_data *data) +{ + unsigned int count = data->res.count; + unsigned int base = data->args.pgbase; + struct page **pages; + + if (data->res.eof) + count = data->args.count; + if (unlikely(count == 0)) + return; + pages = &data->args.pages[base >> PAGE_CACHE_SHIFT]; + base &= ~PAGE_CACHE_MASK; + count += base; + for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++) + SetPageUptodate(*pages); + if (count == 0) + return; + /* Was this a short read? */ + if (data->res.eof || data->res.count == data->args.count) + SetPageUptodate(*pages); +} + +/* + * 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 rpc_task *task, void *calldata) +{ + struct nfs_read_data *data = calldata; + + if (nfs_readpage_result(task, data) != 0) + return; + if (task->tk_status < 0) + return; + /* + * Note: nfs_readpage_retry may change the values of + * data->args. In the multi-page case, we therefore need + * to ensure that we call nfs_readpage_set_pages_uptodate() + * first. + */ + nfs_readpage_truncate_uninitialised_page(data); + nfs_readpage_set_pages_uptodate(data); + nfs_readpage_retry(task, data); +} + +static void nfs_readpage_release_full(void *calldata) +{ + struct nfs_read_data *data = calldata; + + while (!list_empty(&data->pages)) { + struct nfs_page *req = nfs_list_entry(data->pages.next); + + nfs_list_remove_request(req); + nfs_readpage_release(req); + } + nfs_readdata_release(calldata); +} + +static const struct rpc_call_ops nfs_read_full_ops = { + .rpc_call_prepare = nfs_read_prepare, + .rpc_call_done = nfs_readpage_result_full, + .rpc_release = nfs_readpage_release_full, +}; + +/* + * 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); + nfs_inc_stats(inode, NFSIOS_VFSREADPAGE); + nfs_add_stats(inode, NFSIOS_READPAGES, 1); + + /* + * 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_unlock; + if (PageUptodate(page)) + goto out_unlock; + + error = -ESTALE; + if (NFS_STALE(inode)) + goto out_unlock; + + if (file == NULL) { + error = -EBADF; + ctx = nfs_find_open_context(inode, NULL, FMODE_READ); + if (ctx == NULL) + goto out_unlock; + } else + ctx = get_nfs_open_context(nfs_file_open_context(file)); + + if (!IS_SYNC(inode)) { + error = nfs_readpage_from_fscache(ctx, inode, page); + if (error == 0) + goto out; + } + + error = nfs_readpage_async(ctx, inode, page); + +out: + put_nfs_open_context(ctx); + return error; +out_unlock: + unlock_page(page); + return error; +} + +struct nfs_readdesc { + struct nfs_pageio_descriptor *pgio; + 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; + int error; + + len = nfs_page_length(page); + if (len == 0) + return nfs_return_empty_page(page); + + new = nfs_create_request(desc->ctx, inode, page, 0, len); + if (IS_ERR(new)) + goto out_error; + + if (len < PAGE_CACHE_SIZE) + zero_user_segment(page, len, PAGE_CACHE_SIZE); + if (!nfs_pageio_add_request(desc->pgio, new)) { + error = desc->pgio->pg_error; + goto out_unlock; + } + return 0; +out_error: + error = PTR_ERR(new); +out_unlock: + unlock_page(page); + return error; +} + +int nfs_readpages(struct file *filp, struct address_space *mapping, + struct list_head *pages, unsigned nr_pages) +{ + struct nfs_pageio_descriptor pgio; + struct nfs_readdesc desc = { + .pgio = &pgio, + }; + struct inode *inode = mapping->host; + unsigned long npages; + int ret = -ESTALE; + + dprintk("NFS: nfs_readpages (%s/%Ld %d)\n", + inode->i_sb->s_id, + (long long)NFS_FILEID(inode), + nr_pages); + nfs_inc_stats(inode, NFSIOS_VFSREADPAGES); + + if (NFS_STALE(inode)) + goto out; + + if (filp == NULL) { + desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ); + if (desc.ctx == NULL) + return -EBADF; + } else + desc.ctx = get_nfs_open_context(nfs_file_open_context(filp)); + + /* attempt to read as many of the pages as possible from the cache + * - this returns -ENOBUFS immediately if the cookie is negative + */ + ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping, + pages, &nr_pages); + if (ret == 0) + goto read_complete; /* all pages were read */ + + nfs_pageio_init_read(&pgio, inode); + + ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc); + + nfs_pageio_complete(&pgio); + npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; + nfs_add_stats(inode, NFSIOS_READPAGES, npages); +read_complete: + put_nfs_open_context(desc.ctx); +out: + return ret; +} + +int __init nfs_init_readpagecache(void) +{ + nfs_rdata_cachep = kmem_cache_create("nfs_read_data", + sizeof(struct nfs_read_data), + 0, SLAB_HWCACHE_ALIGN, + NULL); + if (nfs_rdata_cachep == NULL) + return -ENOMEM; + + return 0; +} + +void nfs_destroy_readpagecache(void) +{ + kmem_cache_destroy(nfs_rdata_cachep); +} |