1 files changed, 209 insertions, 664 deletions

diff --git a/fs/afs/write.c b/fs/afs/write.c
index a890db4b9898..93ad86ff3345 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -1,678 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* handling of writes to regular files and writing back to the server
  *
  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
  */
+
 #include <linux/backing-dev.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/pagemap.h>
 #include <linux/writeback.h>
 #include <linux/pagevec.h>
-#include <linux/aio.h>
+#include <linux/netfs.h>
+#include <trace/events/netfs.h>
 #include "internal.h"
 
-static int afs_write_back_from_locked_page(struct afs_writeback *wb,
-					   struct page *page);
-
-/*
- * mark a page as having been made dirty and thus needing writeback
- */
-int afs_set_page_dirty(struct page *page)
-{
-	_enter("");
-	return __set_page_dirty_nobuffers(page);
-}
-
-/*
- * unlink a writeback record because its usage has reached zero
- * - must be called with the wb->vnode->writeback_lock held
- */
-static void afs_unlink_writeback(struct afs_writeback *wb)
-{
-	struct afs_writeback *front;
-	struct afs_vnode *vnode = wb->vnode;
-
-	list_del_init(&wb->link);
-	if (!list_empty(&vnode->writebacks)) {
-		/* if an fsync rises to the front of the queue then wake it
-		 * up */
-		front = list_entry(vnode->writebacks.next,
-				   struct afs_writeback, link);
-		if (front->state == AFS_WBACK_SYNCING) {
-			_debug("wake up sync");
-			front->state = AFS_WBACK_COMPLETE;
-			wake_up(&front->waitq);
-		}
-	}
-}
-
-/*
- * free a writeback record
- */
-static void afs_free_writeback(struct afs_writeback *wb)
-{
-	_enter("");
-	key_put(wb->key);
-	kfree(wb);
-}
-
 /*
- * dispose of a reference to a writeback record
+ * completion of write to server
  */
-void afs_put_writeback(struct afs_writeback *wb)
+static void afs_pages_written_back(struct afs_vnode *vnode, loff_t start, unsigned int len)
 {
-	struct afs_vnode *vnode = wb->vnode;
-
-	_enter("{%d}", wb->usage);
+	_enter("{%llx:%llu},{%x @%llx}",
+	       vnode->fid.vid, vnode->fid.vnode, len, start);
 
-	spin_lock(&vnode->writeback_lock);
-	if (--wb->usage == 0)
-		afs_unlink_writeback(wb);
-	else
-		wb = NULL;
-	spin_unlock(&vnode->writeback_lock);
-	if (wb)
-		afs_free_writeback(wb);
+	afs_prune_wb_keys(vnode);
+	_leave("");
 }
 
 /*
- * partly or wholly fill a page that's under preparation for writing
+ * Find a key to use for the writeback.  We cached the keys used to author the
+ * writes on the vnode.  wreq->netfs_priv2 will contain the last writeback key
+ * record used or NULL and we need to start from there if it's set.
+ * wreq->netfs_priv will be set to the key itself or NULL.
  */
-static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
-			 loff_t pos, struct page *page)
+static void afs_get_writeback_key(struct netfs_io_request *wreq)
 {
-	loff_t i_size;
-	int ret;
-	int len;
+	struct afs_wb_key *wbk, *old = wreq->netfs_priv2;
+	struct afs_vnode *vnode = AFS_FS_I(wreq->inode);
 
-	_enter(",,%llu", (unsigned long long)pos);
+	key_put(wreq->netfs_priv);
+	wreq->netfs_priv = NULL;
+	wreq->netfs_priv2 = NULL;
 
-	i_size = i_size_read(&vnode->vfs_inode);
-	if (pos + PAGE_CACHE_SIZE > i_size)
-		len = i_size - pos;
+	spin_lock(&vnode->wb_lock);
+	if (old)
+		wbk = list_next_entry(old, vnode_link);
 	else
-		len = PAGE_CACHE_SIZE;
-
-	ret = afs_vnode_fetch_data(vnode, key, pos, len, page);
-	if (ret < 0) {
-		if (ret == -ENOENT) {
-			_debug("got NOENT from server"
-			       " - marking file deleted and stale");
-			set_bit(AFS_VNODE_DELETED, &vnode->flags);
-			ret = -ESTALE;
-		}
-	}
-
-	_leave(" = %d", ret);
-	return ret;
-}
-
-/*
- * prepare to perform part of a write to a page
- */
-int afs_write_begin(struct file *file, struct address_space *mapping,
-		    loff_t pos, unsigned len, unsigned flags,
-		    struct page **pagep, void **fsdata)
-{
-	struct afs_writeback *candidate, *wb;
-	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
-	struct page *page;
-	struct key *key = file->private_data;
-	unsigned from = pos & (PAGE_CACHE_SIZE - 1);
-	unsigned to = from + len;
-	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
-	int ret;
-
-	_enter("{%x:%u},{%lx},%u,%u",
-	       vnode->fid.vid, vnode->fid.vnode, index, from, to);
-
-	candidate = kzalloc(sizeof(*candidate), GFP_KERNEL);
-	if (!candidate)
-		return -ENOMEM;
-	candidate->vnode = vnode;
-	candidate->first = candidate->last = index;
-	candidate->offset_first = from;
-	candidate->to_last = to;
-	INIT_LIST_HEAD(&candidate->link);
-	candidate->usage = 1;
-	candidate->state = AFS_WBACK_PENDING;
-	init_waitqueue_head(&candidate->waitq);
-
-	page = grab_cache_page_write_begin(mapping, index, flags);
-	if (!page) {
-		kfree(candidate);
-		return -ENOMEM;
-	}
-	*pagep = page;
-	/* page won't leak in error case: it eventually gets cleaned off LRU */
-
-	if (!PageUptodate(page) && len != PAGE_CACHE_SIZE) {
-		ret = afs_fill_page(vnode, key, index << PAGE_CACHE_SHIFT, page);
-		if (ret < 0) {
-			kfree(candidate);
-			_leave(" = %d [prep]", ret);
-			return ret;
-		}
-		SetPageUptodate(page);
-	}
-
-try_again:
-	spin_lock(&vnode->writeback_lock);
-
-	/* see if this page is already pending a writeback under a suitable key
-	 * - if so we can just join onto that one */
-	wb = (struct afs_writeback *) page_private(page);
-	if (wb) {
-		if (wb->key == key && wb->state == AFS_WBACK_PENDING)
-			goto subsume_in_current_wb;
-		goto flush_conflicting_wb;
-	}
-
-	if (index > 0) {
-		/* see if we can find an already pending writeback that we can
-		 * append this page to */
-		list_for_each_entry(wb, &vnode->writebacks, link) {
-			if (wb->last == index - 1 && wb->key == key &&
-			    wb->state == AFS_WBACK_PENDING)
-				goto append_to_previous_wb;
+		wbk = list_first_entry(&vnode->wb_keys, struct afs_wb_key, vnode_link);
+
+	list_for_each_entry_from(wbk, &vnode->wb_keys, vnode_link) {
+		_debug("wbk %u", key_serial(wbk->key));
+		if (key_validate(wbk->key) == 0) {
+			refcount_inc(&wbk->usage);
+			wreq->netfs_priv = key_get(wbk->key);
+			wreq->netfs_priv2 = wbk;
+			_debug("USE WB KEY %u", key_serial(wbk->key));
+			break;
 		}
 	}
 
-	list_add_tail(&candidate->link, &vnode->writebacks);
-	candidate->key = key_get(key);
-	spin_unlock(&vnode->writeback_lock);
-	SetPagePrivate(page);
-	set_page_private(page, (unsigned long) candidate);
-	_leave(" = 0 [new]");
-	return 0;
-
-subsume_in_current_wb:
-	_debug("subsume");
-	ASSERTRANGE(wb->first, <=, index, <=, wb->last);
-	if (index == wb->first && from < wb->offset_first)
-		wb->offset_first = from;
-	if (index == wb->last && to > wb->to_last)
-		wb->to_last = to;
-	spin_unlock(&vnode->writeback_lock);
-	kfree(candidate);
-	_leave(" = 0 [sub]");
-	return 0;
-
-append_to_previous_wb:
-	_debug("append into %lx-%lx", wb->first, wb->last);
-	wb->usage++;
-	wb->last++;
-	wb->to_last = to;
-	spin_unlock(&vnode->writeback_lock);
-	SetPagePrivate(page);
-	set_page_private(page, (unsigned long) wb);
-	kfree(candidate);
-	_leave(" = 0 [app]");
-	return 0;
-
-	/* the page is currently bound to another context, so if it's dirty we
-	 * need to flush it before we can use the new context */
-flush_conflicting_wb:
-	_debug("flush conflict");
-	if (wb->state == AFS_WBACK_PENDING)
-		wb->state = AFS_WBACK_CONFLICTING;
-	spin_unlock(&vnode->writeback_lock);
-	if (PageDirty(page)) {
-		ret = afs_write_back_from_locked_page(wb, page);
-		if (ret < 0) {
-			afs_put_writeback(candidate);
-			_leave(" = %d", ret);
-			return ret;
-		}
-	}
+	spin_unlock(&vnode->wb_lock);
 
-	/* the page holds a ref on the writeback record */
-	afs_put_writeback(wb);
-	set_page_private(page, 0);
-	ClearPagePrivate(page);
-	goto try_again;
+	afs_put_wb_key(old);
 }
 
-/*
- * finalise part of a write to a page
- */
-int afs_write_end(struct file *file, struct address_space *mapping,
-		  loff_t pos, unsigned len, unsigned copied,
-		  struct page *page, void *fsdata)
+static void afs_store_data_success(struct afs_operation *op)
 {
-	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
-	loff_t i_size, maybe_i_size;
-
-	_enter("{%x:%u},{%lx}",
-	       vnode->fid.vid, vnode->fid.vnode, page->index);
-
-	maybe_i_size = pos + copied;
-
-	i_size = i_size_read(&vnode->vfs_inode);
-	if (maybe_i_size > i_size) {
-		spin_lock(&vnode->writeback_lock);
-		i_size = i_size_read(&vnode->vfs_inode);
-		if (maybe_i_size > i_size)
-			i_size_write(&vnode->vfs_inode, maybe_i_size);
-		spin_unlock(&vnode->writeback_lock);
+	struct afs_vnode *vnode = op->file[0].vnode;
+
+	op->ctime = op->file[0].scb.status.mtime_client;
+	afs_vnode_commit_status(op, &op->file[0]);
+	if (!afs_op_error(op)) {
+		afs_pages_written_back(vnode, op->store.pos, op->store.size);
+		afs_stat_v(vnode, n_stores);
+		atomic_long_add(op->store.size, &afs_v2net(vnode)->n_store_bytes);
 	}
-
-	set_page_dirty(page);
-	if (PageDirty(page))
-		_debug("dirtied");
-	unlock_page(page);
-	page_cache_release(page);
-
-	return copied;
 }
 
-/*
- * kill all the pages in the given range
- */
-static void afs_kill_pages(struct afs_vnode *vnode, bool error,
-			   pgoff_t first, pgoff_t last)
-{
-	struct pagevec pv;
-	unsigned count, loop;
-
-	_enter("{%x:%u},%lx-%lx",
-	       vnode->fid.vid, vnode->fid.vnode, first, last);
-
-	pagevec_init(&pv, 0);
-
-	do {
-		_debug("kill %lx-%lx", first, last);
-
-		count = last - first + 1;
-		if (count > PAGEVEC_SIZE)
-			count = PAGEVEC_SIZE;
-		pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping,
-					      first, count, pv.pages);
-		ASSERTCMP(pv.nr, ==, count);
-
-		for (loop = 0; loop < count; loop++) {
-			ClearPageUptodate(pv.pages[loop]);
-			if (error)
-				SetPageError(pv.pages[loop]);
-			end_page_writeback(pv.pages[loop]);
-		}
-
-		__pagevec_release(&pv);
-	} while (first < last);
-
-	_leave("");
-}
+static const struct afs_operation_ops afs_store_data_operation = {
+	.issue_afs_rpc	= afs_fs_store_data,
+	.issue_yfs_rpc	= yfs_fs_store_data,
+	.success	= afs_store_data_success,
+};
 
 /*
- * synchronously write back the locked page and any subsequent non-locked dirty
- * pages also covered by the same writeback record
+ * Prepare a subrequest to write to the server.  This sets the max_len
+ * parameter.
  */
-static int afs_write_back_from_locked_page(struct afs_writeback *wb,
-					   struct page *primary_page)
+void afs_prepare_write(struct netfs_io_subrequest *subreq)
 {
-	struct page *pages[8], *page;
-	unsigned long count;
-	unsigned n, offset, to;
-	pgoff_t start, first, last;
-	int loop, ret;
-
-	_enter(",%lx", primary_page->index);
-
-	count = 1;
-	if (!clear_page_dirty_for_io(primary_page))
-		BUG();
-	if (test_set_page_writeback(primary_page))
-		BUG();
-
-	/* find all consecutive lockable dirty pages, stopping when we find a
-	 * page that is not immediately lockable, is not dirty or is missing,
-	 * or we reach the end of the range */
-	start = primary_page->index;
-	if (start >= wb->last)
-		goto no_more;
-	start++;
-	do {
-		_debug("more %lx [%lx]", start, count);
-		n = wb->last - start + 1;
-		if (n > ARRAY_SIZE(pages))
-			n = ARRAY_SIZE(pages);
-		n = find_get_pages_contig(wb->vnode->vfs_inode.i_mapping,
-					  start, n, pages);
-		_debug("fgpc %u", n);
-		if (n == 0)
-			goto no_more;
-		if (pages[0]->index != start) {
-			do {
-				put_page(pages[--n]);
-			} while (n > 0);
-			goto no_more;
-		}
-
-		for (loop = 0; loop < n; loop++) {
-			page = pages[loop];
-			if (page->index > wb->last)
-				break;
-			if (!trylock_page(page))
-				break;
-			if (!PageDirty(page) ||
-			    page_private(page) != (unsigned long) wb) {
-				unlock_page(page);
-				break;
-			}
-			if (!clear_page_dirty_for_io(page))
-				BUG();
-			if (test_set_page_writeback(page))
-				BUG();
-			unlock_page(page);
-			put_page(page);
-		}
-		count += loop;
-		if (loop < n) {
-			for (; loop < n; loop++)
-				put_page(pages[loop]);
-			goto no_more;
-		}
-
-		start += loop;
-	} while (start <= wb->last && count < 65536);
-
-no_more:
-	/* we now have a contiguous set of dirty pages, each with writeback set
-	 * and the dirty mark cleared; the first page is locked and must remain
-	 * so, all the rest are unlocked */
-	first = primary_page->index;
-	last = first + count - 1;
-
-	offset = (first == wb->first) ? wb->offset_first : 0;
-	to = (last == wb->last) ? wb->to_last : PAGE_SIZE;
-
-	_debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to);
-
-	ret = afs_vnode_store_data(wb, first, last, offset, to);
-	if (ret < 0) {
-		switch (ret) {
-		case -EDQUOT:
-		case -ENOSPC:
-			set_bit(AS_ENOSPC,
-				&wb->vnode->vfs_inode.i_mapping->flags);
-			break;
-		case -EROFS:
-		case -EIO:
-		case -EREMOTEIO:
-		case -EFBIG:
-		case -ENOENT:
-		case -ENOMEDIUM:
-		case -ENXIO:
-			afs_kill_pages(wb->vnode, true, first, last);
-			set_bit(AS_EIO, &wb->vnode->vfs_inode.i_mapping->flags);
-			break;
-		case -EACCES:
-		case -EPERM:
-		case -ENOKEY:
-		case -EKEYEXPIRED:
-		case -EKEYREJECTED:
-		case -EKEYREVOKED:
-			afs_kill_pages(wb->vnode, false, first, last);
-			break;
-		default:
-			break;
-		}
-	} else {
-		ret = count;
-	}
+	struct netfs_io_stream *stream = &subreq->rreq->io_streams[subreq->stream_nr];
 
-	_leave(" = %d", ret);
-	return ret;
+	//if (test_bit(NETFS_SREQ_RETRYING, &subreq->flags))
+	//	subreq->max_len = 512 * 1024;
+	//else
+	stream->sreq_max_len = 256 * 1024 * 1024;
 }
 
 /*
- * write a page back to the server
- * - the caller locked the page for us
+ * Issue a subrequest to write to the server.
  */
-int afs_writepage(struct page *page, struct writeback_control *wbc)
+static void afs_issue_write_worker(struct work_struct *work)
 {
-	struct afs_writeback *wb;
-	int ret;
-
-	_enter("{%lx},", page->index);
-
-	wb = (struct afs_writeback *) page_private(page);
-	ASSERT(wb != NULL);
-
-	ret = afs_write_back_from_locked_page(wb, page);
-	unlock_page(page);
-	if (ret < 0) {
-		_leave(" = %d", ret);
-		return 0;
+	struct netfs_io_subrequest *subreq = container_of(work, struct netfs_io_subrequest, work);
+	struct netfs_io_request *wreq = subreq->rreq;
+	struct afs_operation *op;
+	struct afs_vnode *vnode = AFS_FS_I(wreq->inode);
+	unsigned long long pos = subreq->start + subreq->transferred;
+	size_t len = subreq->len - subreq->transferred;
+	int ret = -ENOKEY;
+
+	_enter("R=%x[%x],%s{%llx:%llu.%u},%llx,%zx",
+	       wreq->debug_id, subreq->debug_index,
+	       vnode->volume->name,
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique,
+	       pos, len);
+
+#if 0 // Error injection
+	if (subreq->debug_index == 3)
+		return netfs_write_subrequest_terminated(subreq, -ENOANO);
+
+	if (!subreq->retry_count) {
+		set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
+		return netfs_write_subrequest_terminated(subreq, -EAGAIN);
 	}
+#endif
 
-	wbc->nr_to_write -= ret;
-
-	_leave(" = 0");
-	return 0;
-}
-
-/*
- * write a region of pages back to the server
- */
-static int afs_writepages_region(struct address_space *mapping,
-				 struct writeback_control *wbc,
-				 pgoff_t index, pgoff_t end, pgoff_t *_next)
-{
-	struct afs_writeback *wb;
-	struct page *page;
-	int ret, n;
-
-	_enter(",,%lx,%lx,", index, end);
-
-	do {
-		n = find_get_pages_tag(mapping, &index, PAGECACHE_TAG_DIRTY,
-				       1, &page);
-		if (!n)
-			break;
-
-		_debug("wback %lx", page->index);
-
-		if (page->index > end) {
-			*_next = index;
-			page_cache_release(page);
-			_leave(" = 0 [%lx]", *_next);
-			return 0;
-		}
-
-		/* at this point we hold neither mapping->tree_lock nor lock on
-		 * the page itself: the page may be truncated or invalidated
-		 * (changing page->mapping to NULL), or even swizzled back from
-		 * swapper_space to tmpfs file mapping
+	op = afs_alloc_operation(wreq->netfs_priv, vnode->volume);
+	if (IS_ERR(op))
+		return netfs_write_subrequest_terminated(subreq, -EAGAIN);
+
+	afs_op_set_vnode(op, 0, vnode);
+	op->file[0].dv_delta	= 1;
+	op->file[0].modification = true;
+	op->store.pos		= pos;
+	op->store.size		= len;
+	op->flags		|= AFS_OPERATION_UNINTR;
+	op->ops			= &afs_store_data_operation;
+
+	afs_begin_vnode_operation(op);
+
+	op->store.write_iter	= &subreq->io_iter;
+	op->store.i_size	= umax(pos + len, vnode->netfs.remote_i_size);
+	op->mtime		= inode_get_mtime(&vnode->netfs.inode);
+
+	afs_wait_for_operation(op);
+	ret = afs_put_operation(op);
+	switch (ret) {
+	case 0:
+		__set_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags);
+		break;
+	case -EACCES:
+	case -EPERM:
+	case -ENOKEY:
+	case -EKEYEXPIRED:
+	case -EKEYREJECTED:
+	case -EKEYREVOKED:
+		/* If there are more keys we can try, use the retry algorithm
+		 * to rotate the keys.
 		 */
-		lock_page(page);
-
-		if (page->mapping != mapping) {
-			unlock_page(page);
-			page_cache_release(page);
-			continue;
-		}
-
-		if (wbc->sync_mode != WB_SYNC_NONE)
-			wait_on_page_writeback(page);
-
-		if (PageWriteback(page) || !PageDirty(page)) {
-			unlock_page(page);
-			continue;
-		}
-
-		wb = (struct afs_writeback *) page_private(page);
-		ASSERT(wb != NULL);
-
-		spin_lock(&wb->vnode->writeback_lock);
-		wb->state = AFS_WBACK_WRITING;
-		spin_unlock(&wb->vnode->writeback_lock);
-
-		ret = afs_write_back_from_locked_page(wb, page);
-		unlock_page(page);
-		page_cache_release(page);
-		if (ret < 0) {
-			_leave(" = %d", ret);
-			return ret;
-		}
-
-		wbc->nr_to_write -= ret;
-
-		cond_resched();
-	} while (index < end && wbc->nr_to_write > 0);
+		if (wreq->netfs_priv2)
+			set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
+		break;
+	}
 
-	*_next = index;
-	_leave(" = 0 [%lx]", *_next);
-	return 0;
+	netfs_write_subrequest_terminated(subreq, ret < 0 ? ret : subreq->len);
 }
 
-/*
- * write some of the pending data back to the server
- */
-int afs_writepages(struct address_space *mapping,
-		   struct writeback_control *wbc)
+void afs_issue_write(struct netfs_io_subrequest *subreq)
 {
-	pgoff_t start, end, next;
-	int ret;
-
-	_enter("");
-
-	if (wbc->range_cyclic) {
-		start = mapping->writeback_index;
-		end = -1;
-		ret = afs_writepages_region(mapping, wbc, start, end, &next);
-		if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
-			ret = afs_writepages_region(mapping, wbc, 0, start,
-						    &next);
-		mapping->writeback_index = next;
-	} else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
-		end = (pgoff_t)(LLONG_MAX >> PAGE_CACHE_SHIFT);
-		ret = afs_writepages_region(mapping, wbc, 0, end, &next);
-		if (wbc->nr_to_write > 0)
-			mapping->writeback_index = next;
-	} else {
-		start = wbc->range_start >> PAGE_CACHE_SHIFT;
-		end = wbc->range_end >> PAGE_CACHE_SHIFT;
-		ret = afs_writepages_region(mapping, wbc, start, end, &next);
-	}
-
-	_leave(" = %d", ret);
-	return ret;
+	subreq->work.func = afs_issue_write_worker;
+	if (!queue_work(system_dfl_wq, &subreq->work))
+		WARN_ON_ONCE(1);
 }
 
 /*
- * completion of write to server
+ * Writeback calls this when it finds a folio that needs uploading.  This isn't
+ * called if writeback only has copy-to-cache to deal with.
  */
-void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call)
+void afs_begin_writeback(struct netfs_io_request *wreq)
 {
-	struct afs_writeback *wb = call->wb;
-	struct pagevec pv;
-	unsigned count, loop;
-	pgoff_t first = call->first, last = call->last;
-	bool free_wb;
-
-	_enter("{%x:%u},{%lx-%lx}",
-	       vnode->fid.vid, vnode->fid.vnode, first, last);
-
-	ASSERT(wb != NULL);
-
-	pagevec_init(&pv, 0);
-
-	do {
-		_debug("done %lx-%lx", first, last);
-
-		count = last - first + 1;
-		if (count > PAGEVEC_SIZE)
-			count = PAGEVEC_SIZE;
-		pv.nr = find_get_pages_contig(call->mapping, first, count,
-					      pv.pages);
-		ASSERTCMP(pv.nr, ==, count);
-
-		spin_lock(&vnode->writeback_lock);
-		for (loop = 0; loop < count; loop++) {
-			struct page *page = pv.pages[loop];
-			end_page_writeback(page);
-			if (page_private(page) == (unsigned long) wb) {
-				set_page_private(page, 0);
-				ClearPagePrivate(page);
-				wb->usage--;
-			}
-		}
-		free_wb = false;
-		if (wb->usage == 0) {
-			afs_unlink_writeback(wb);
-			free_wb = true;
-		}
-		spin_unlock(&vnode->writeback_lock);
-		first += count;
-		if (free_wb) {
-			afs_free_writeback(wb);
-			wb = NULL;
-		}
-
-		__pagevec_release(&pv);
-	} while (first <= last);
-
-	_leave("");
+	if (S_ISREG(wreq->inode->i_mode))
+		afs_get_writeback_key(wreq);
 }
 
 /*
- * write to an AFS file
+ * Prepare to retry the writes in request.  Use this to try rotating the
+ * available writeback keys.
  */
-ssize_t afs_file_write(struct kiocb *iocb, const struct iovec *iov,
-		       unsigned long nr_segs, loff_t pos)
+void afs_retry_request(struct netfs_io_request *wreq, struct netfs_io_stream *stream)
 {
-	struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp));
-	ssize_t result;
-	size_t count = iov_length(iov, nr_segs);
-
-	_enter("{%x.%u},{%zu},%lu,",
-	       vnode->fid.vid, vnode->fid.vnode, count, nr_segs);
-
-	if (IS_SWAPFILE(&vnode->vfs_inode)) {
-		printk(KERN_INFO
-		       "AFS: Attempt to write to active swap file!\n");
-		return -EBUSY;
+	struct netfs_io_subrequest *subreq =
+		list_first_entry(&stream->subrequests,
+				 struct netfs_io_subrequest, rreq_link);
+
+	switch (wreq->origin) {
+	case NETFS_READAHEAD:
+	case NETFS_READPAGE:
+	case NETFS_READ_GAPS:
+	case NETFS_READ_SINGLE:
+	case NETFS_READ_FOR_WRITE:
+	case NETFS_UNBUFFERED_READ:
+	case NETFS_DIO_READ:
+		return;
+	default:
+		break;
 	}
 
-	if (!count)
-		return 0;
-
-	result = generic_file_aio_write(iocb, iov, nr_segs, pos);
-	if (IS_ERR_VALUE(result)) {
-		_leave(" = %zd", result);
-		return result;
+	switch (subreq->error) {
+	case -EACCES:
+	case -EPERM:
+	case -ENOKEY:
+	case -EKEYEXPIRED:
+	case -EKEYREJECTED:
+	case -EKEYREVOKED:
+		afs_get_writeback_key(wreq);
+		if (!wreq->netfs_priv)
+			stream->failed = true;
+		break;
 	}
-
-	_leave(" = %zd", result);
-	return result;
 }
 
 /*
- * flush the vnode to the fileserver
+ * write some of the pending data back to the server
  */
-int afs_writeback_all(struct afs_vnode *vnode)
+int afs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 {
-	struct address_space *mapping = vnode->vfs_inode.i_mapping;
-	struct writeback_control wbc = {
-		.sync_mode	= WB_SYNC_ALL,
-		.nr_to_write	= LONG_MAX,
-		.range_cyclic	= 1,
-	};
+	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
 	int ret;
 
-	_enter("");
-
-	ret = mapping->a_ops->writepages(mapping, &wbc);
-	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+	/* We have to be careful as we can end up racing with setattr()
+	 * truncating the pagecache since the caller doesn't take a lock here
+	 * to prevent it.
+	 */
+	if (wbc->sync_mode == WB_SYNC_ALL)
+		down_read(&vnode->validate_lock);
+	else if (!down_read_trylock(&vnode->validate_lock))
+		return 0;
 
-	_leave(" = %d", ret);
+	ret = netfs_writepages(mapping, wbc);
+	up_read(&vnode->validate_lock);
 	return ret;
 }
 
@@ -683,82 +252,58 @@ int afs_writeback_all(struct afs_vnode *vnode)
  */
 int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 {
-	struct dentry *dentry = file->f_path.dentry;
-	struct inode *inode = file->f_mapping->host;
-	struct afs_writeback *wb, *xwb;
-	struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
+	struct afs_file *af = file->private_data;
 	int ret;
 
-	_enter("{%x:%u},{n=%s},%d",
-	       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
+	_enter("{%llx:%llu},{n=%pD},%d",
+	       vnode->fid.vid, vnode->fid.vnode, file,
 	       datasync);
 
-	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
-	if (ret)
+	ret = afs_validate(vnode, af->key);
+	if (ret < 0)
 		return ret;
-	mutex_lock(&inode->i_mutex);
-
-	/* use a writeback record as a marker in the queue - when this reaches
-	 * the front of the queue, all the outstanding writes are either
-	 * completed or rejected */
-	wb = kzalloc(sizeof(*wb), GFP_KERNEL);
-	if (!wb) {
-		ret = -ENOMEM;
-		goto out;
-	}
-	wb->vnode = vnode;
-	wb->first = 0;
-	wb->last = -1;
-	wb->offset_first = 0;
-	wb->to_last = PAGE_SIZE;
-	wb->usage = 1;
-	wb->state = AFS_WBACK_SYNCING;
-	init_waitqueue_head(&wb->waitq);
-
-	spin_lock(&vnode->writeback_lock);
-	list_for_each_entry(xwb, &vnode->writebacks, link) {
-		if (xwb->state == AFS_WBACK_PENDING)
-			xwb->state = AFS_WBACK_CONFLICTING;
-	}
-	list_add_tail(&wb->link, &vnode->writebacks);
-	spin_unlock(&vnode->writeback_lock);
-
-	/* push all the outstanding writebacks to the server */
-	ret = afs_writeback_all(vnode);
-	if (ret < 0) {
-		afs_put_writeback(wb);
-		_leave(" = %d [wb]", ret);
-		goto out;
-	}
 
-	/* wait for the preceding writes to actually complete */
-	ret = wait_event_interruptible(wb->waitq,
-				       wb->state == AFS_WBACK_COMPLETE ||
-				       vnode->writebacks.next == &wb->link);
-	afs_put_writeback(wb);
-	_leave(" = %d", ret);
-out:
-	mutex_unlock(&inode->i_mutex);
-	return ret;
+	return file_write_and_wait_range(file, start, end);
 }
 
 /*
  * notification that a previously read-only page is about to become writable
  * - if it returns an error, the caller will deliver a bus error signal
  */
-int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
+vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
 {
-	struct afs_vnode *vnode = AFS_FS_I(vma->vm_file->f_mapping->host);
+	struct file *file = vmf->vma->vm_file;
 
-	_enter("{{%x:%u}},{%lx}",
-	       vnode->fid.vid, vnode->fid.vnode, page->index);
+	if (afs_validate(AFS_FS_I(file_inode(file)), afs_file_key(file)) < 0)
+		return VM_FAULT_SIGBUS;
+	return netfs_page_mkwrite(vmf, NULL);
+}
 
-	/* wait for the page to be written to the cache before we allow it to
-	 * be modified */
-#ifdef CONFIG_AFS_FSCACHE
-	fscache_wait_on_page_write(vnode->cache, page);
-#endif
+/*
+ * Prune the keys cached for writeback.  The caller must hold vnode->wb_lock.
+ */
+void afs_prune_wb_keys(struct afs_vnode *vnode)
+{
+	LIST_HEAD(graveyard);
+	struct afs_wb_key *wbk, *tmp;
 
-	_leave(" = 0");
-	return 0;
+	/* Discard unused keys */
+	spin_lock(&vnode->wb_lock);
+
+	if (!mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_WRITEBACK) &&
+	    !mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_DIRTY)) {
+		list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) {
+			if (refcount_read(&wbk->usage) == 1)
+				list_move(&wbk->vnode_link, &graveyard);
+		}
+	}
+
+	spin_unlock(&vnode->wb_lock);
+
+	while (!list_empty(&graveyard)) {
+		wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link);
+		list_del(&wbk->vnode_link);
+		afs_put_wb_key(wbk);
+	}
 }