CIFS: Add support for direct I/O write
With direct I/O write, user supplied buffers are pinned to the memory and data are transferred directly from user buffers to the transport layer. Change in v3: add support for kernel AIO Change in v4: Refactor common write code to __cifs_writev for direct and non-direct I/O. Retry on direct I/O failure. Signed-off-by: Long Li <longli@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>hifive-unleashed-5.1
Long Li
Steve French
parent
6e6e2b86c2
commit
8c5f9c1ab7
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@ -104,6 +104,7 @@ extern ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to);
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extern ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter *to);
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extern ssize_t cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to);
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extern ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from);
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extern ssize_t cifs_direct_writev(struct kiocb *iocb, struct iov_iter *from);
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extern ssize_t cifs_strict_writev(struct kiocb *iocb, struct iov_iter *from);
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extern int cifs_lock(struct file *, int, struct file_lock *);
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extern int cifs_fsync(struct file *, loff_t, loff_t, int);
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204
fs/cifs/file.c
204
fs/cifs/file.c
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@ -2537,6 +2537,61 @@ wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from,
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return 0;
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}
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static int
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cifs_resend_wdata(struct cifs_writedata *wdata, struct list_head *wdata_list,
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struct cifs_aio_ctx *ctx)
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{
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int wait_retry = 0;
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unsigned int wsize, credits;
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int rc;
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struct TCP_Server_Info *server =
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tlink_tcon(wdata->cfile->tlink)->ses->server;
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/*
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* Try to resend this wdata, waiting for credits up to 3 seconds.
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* Note: we are attempting to resend the whole wdata not in segments
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*/
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do {
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rc = server->ops->wait_mtu_credits(
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server, wdata->bytes, &wsize, &credits);
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if (rc)
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break;
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if (wsize < wdata->bytes) {
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add_credits_and_wake_if(server, credits, 0);
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msleep(1000);
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wait_retry++;
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}
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} while (wsize < wdata->bytes && wait_retry < 3);
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if (wsize < wdata->bytes) {
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rc = -EBUSY;
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goto out;
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}
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rc = -EAGAIN;
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while (rc == -EAGAIN) {
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rc = 0;
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if (wdata->cfile->invalidHandle)
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rc = cifs_reopen_file(wdata->cfile, false);
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if (!rc)
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rc = server->ops->async_writev(wdata,
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cifs_uncached_writedata_release);
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}
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if (!rc) {
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list_add_tail(&wdata->list, wdata_list);
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return 0;
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}
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add_credits_and_wake_if(server, wdata->credits, 0);
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out:
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kref_put(&wdata->refcount, cifs_uncached_writedata_release);
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return rc;
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}
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static int
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cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
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struct cifsFileInfo *open_file,
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@ -2551,6 +2606,8 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
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loff_t saved_offset = offset;
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pid_t pid;
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struct TCP_Server_Info *server;
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struct page **pagevec;
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size_t start;
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if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
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pid = open_file->pid;
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@ -2567,38 +2624,76 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
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if (rc)
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break;
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nr_pages = get_numpages(wsize, len, &cur_len);
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wdata = cifs_writedata_alloc(nr_pages,
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if (ctx->direct_io) {
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cur_len = iov_iter_get_pages_alloc(
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from, &pagevec, wsize, &start);
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if (cur_len < 0) {
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cifs_dbg(VFS,
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"direct_writev couldn't get user pages "
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"(rc=%zd) iter type %d iov_offset %zd "
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"count %zd\n",
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cur_len, from->type,
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from->iov_offset, from->count);
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dump_stack();
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break;
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}
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iov_iter_advance(from, cur_len);
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nr_pages =
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(cur_len + start + PAGE_SIZE - 1) / PAGE_SIZE;
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wdata = cifs_writedata_direct_alloc(pagevec,
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cifs_uncached_writev_complete);
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if (!wdata) {
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rc = -ENOMEM;
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add_credits_and_wake_if(server, credits, 0);
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break;
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}
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if (!wdata) {
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rc = -ENOMEM;
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add_credits_and_wake_if(server, credits, 0);
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break;
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}
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rc = cifs_write_allocate_pages(wdata->pages, nr_pages);
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if (rc) {
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kfree(wdata);
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add_credits_and_wake_if(server, credits, 0);
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break;
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}
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num_pages = nr_pages;
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rc = wdata_fill_from_iovec(wdata, from, &cur_len, &num_pages);
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if (rc) {
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for (i = 0; i < nr_pages; i++)
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put_page(wdata->pages[i]);
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kfree(wdata);
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add_credits_and_wake_if(server, credits, 0);
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break;
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}
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wdata->page_offset = start;
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wdata->tailsz =
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nr_pages > 1 ?
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cur_len - (PAGE_SIZE - start) -
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(nr_pages - 2) * PAGE_SIZE :
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cur_len;
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} else {
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nr_pages = get_numpages(wsize, len, &cur_len);
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wdata = cifs_writedata_alloc(nr_pages,
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cifs_uncached_writev_complete);
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if (!wdata) {
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rc = -ENOMEM;
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add_credits_and_wake_if(server, credits, 0);
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break;
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}
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/*
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* Bring nr_pages down to the number of pages we actually used,
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* and free any pages that we didn't use.
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*/
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for ( ; nr_pages > num_pages; nr_pages--)
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put_page(wdata->pages[nr_pages - 1]);
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rc = cifs_write_allocate_pages(wdata->pages, nr_pages);
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if (rc) {
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kfree(wdata);
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add_credits_and_wake_if(server, credits, 0);
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break;
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}
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num_pages = nr_pages;
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rc = wdata_fill_from_iovec(
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wdata, from, &cur_len, &num_pages);
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if (rc) {
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for (i = 0; i < nr_pages; i++)
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put_page(wdata->pages[i]);
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kfree(wdata);
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add_credits_and_wake_if(server, credits, 0);
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break;
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}
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/*
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* Bring nr_pages down to the number of pages we
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* actually used, and free any pages that we didn't use.
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*/
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for ( ; nr_pages > num_pages; nr_pages--)
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put_page(wdata->pages[nr_pages - 1]);
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wdata->tailsz = cur_len - ((nr_pages - 1) * PAGE_SIZE);
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}
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wdata->sync_mode = WB_SYNC_ALL;
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wdata->nr_pages = nr_pages;
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@ -2607,7 +2702,6 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
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wdata->pid = pid;
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wdata->bytes = cur_len;
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wdata->pagesz = PAGE_SIZE;
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wdata->tailsz = cur_len - ((nr_pages - 1) * PAGE_SIZE);
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wdata->credits = credits;
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wdata->ctx = ctx;
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kref_get(&ctx->refcount);
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@ -2682,13 +2776,18 @@ restart_loop:
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INIT_LIST_HEAD(&tmp_list);
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list_del_init(&wdata->list);
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iov_iter_advance(&tmp_from,
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if (ctx->direct_io)
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rc = cifs_resend_wdata(
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wdata, &tmp_list, ctx);
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else {
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iov_iter_advance(&tmp_from,
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wdata->offset - ctx->pos);
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rc = cifs_write_from_iter(wdata->offset,
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rc = cifs_write_from_iter(wdata->offset,
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wdata->bytes, &tmp_from,
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ctx->cfile, cifs_sb, &tmp_list,
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ctx);
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}
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list_splice(&tmp_list, &ctx->list);
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@ -2701,8 +2800,9 @@ restart_loop:
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kref_put(&wdata->refcount, cifs_uncached_writedata_release);
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}
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for (i = 0; i < ctx->npages; i++)
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put_page(ctx->bv[i].bv_page);
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if (!ctx->direct_io)
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for (i = 0; i < ctx->npages; i++)
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put_page(ctx->bv[i].bv_page);
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cifs_stats_bytes_written(tcon, ctx->total_len);
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set_bit(CIFS_INO_INVALID_MAPPING, &CIFS_I(dentry->d_inode)->flags);
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@ -2717,7 +2817,8 @@ restart_loop:
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complete(&ctx->done);
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}
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ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
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static ssize_t __cifs_writev(
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struct kiocb *iocb, struct iov_iter *from, bool direct)
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{
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struct file *file = iocb->ki_filp;
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ssize_t total_written = 0;
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@ -2726,13 +2827,18 @@ ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
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struct cifs_sb_info *cifs_sb;
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struct cifs_aio_ctx *ctx;
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struct iov_iter saved_from = *from;
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size_t len = iov_iter_count(from);
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int rc;
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/*
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* BB - optimize the way when signing is disabled. We can drop this
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* extra memory-to-memory copying and use iovec buffers for constructing
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* write request.
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* iov_iter_get_pages_alloc doesn't work with ITER_KVEC.
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* In this case, fall back to non-direct write function.
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* this could be improved by getting pages directly in ITER_KVEC
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*/
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if (direct && from->type & ITER_KVEC) {
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cifs_dbg(FYI, "use non-direct cifs_writev for kvec I/O\n");
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direct = false;
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}
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rc = generic_write_checks(iocb, from);
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if (rc <= 0)
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@ -2756,10 +2862,16 @@ ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
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ctx->pos = iocb->ki_pos;
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rc = setup_aio_ctx_iter(ctx, from, WRITE);
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if (rc) {
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kref_put(&ctx->refcount, cifs_aio_ctx_release);
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return rc;
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if (direct) {
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ctx->direct_io = true;
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ctx->iter = *from;
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ctx->len = len;
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} else {
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rc = setup_aio_ctx_iter(ctx, from, WRITE);
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if (rc) {
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kref_put(&ctx->refcount, cifs_aio_ctx_release);
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return rc;
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}
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}
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/* grab a lock here due to read response handlers can access ctx */
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@ -2809,6 +2921,16 @@ ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
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return total_written;
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}
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ssize_t cifs_direct_writev(struct kiocb *iocb, struct iov_iter *from)
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{
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return __cifs_writev(iocb, from, true);
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}
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ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
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{
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return __cifs_writev(iocb, from, false);
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}
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static ssize_t
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cifs_writev(struct kiocb *iocb, struct iov_iter *from)
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{
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