Merge tag 'afs-next-20171113' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull AFS updates from David Howells:
 "kAFS filesystem driver overhaul.

  The major points of the overhaul are:

   (1) Preliminary groundwork is laid for supporting network-namespacing
       of kAFS. The remainder of the namespacing work requires some way
       to pass namespace information to submounts triggered by an
       automount. This requires something like the mount overhaul that's
       in progress.

   (2) sockaddr_rxrpc is used in preference to in_addr for holding
       addresses internally and add support for talking to the YFS VL
       server. With this, kAFS can do everything over IPv6 as well as
       IPv4 if it's talking to servers that support it.

   (3) Callback handling is overhauled to be generally passive rather
       than active. 'Callbacks' are promises by the server to tell us
       about data and metadata changes. Callbacks are now checked when
       we next touch an inode rather than actively going and looking for
       it where possible.

   (4) File access permit caching is overhauled to store the caching
       information per-inode rather than per-directory, shared over
       subordinate files. Whilst older AFS servers only allow ACLs on
       directories (shared to the files in that directory), newer AFS
       servers break that restriction.

       To improve memory usage and to make it easier to do mass-key
       removal, permit combinations are cached and shared.

   (5) Cell database management is overhauled to allow lighter locks to
       be used and to make cell records autonomous state machines that
       look after getting their own DNS records and cleaning themselves
       up, in particular preventing races in acquiring and relinquishing
       the fscache token for the cell.

   (6) Volume caching is overhauled. The afs_vlocation record is got rid
       of to simplify things and the superblock is now keyed on the cell
       and the numeric volume ID only. The volume record is tied to a
       superblock and normal superblock management is used to mediate
       the lifetime of the volume fscache token.

   (7) File server record caching is overhauled to make server records
       independent of cells and volumes. A server can be in multiple
       cells (in such a case, the administrator must make sure that the
       VL services for all cells correctly reflect the volumes shared
       between those cells).

       Server records are now indexed using the UUID of the server
       rather than the address since a server can have multiple
       addresses.

   (8) File server rotation is overhauled to handle VMOVED, VBUSY (and
       similar), VOFFLINE and VNOVOL indications and to handle rotation
       both of servers and addresses of those servers. The rotation will
       also wait and retry if the server says it is busy.

   (9) Data writeback is overhauled. Each inode no longer stores a list
       of modified sections tagged with the key that authorised it in
       favour of noting the modified region of a page in page->private
       and storing a list of keys that made modifications in the inode.

       This simplifies things and allows other keys to be used to
       actually write to the server if a key that made a modification
       becomes useless.

  (10) Writable mmap() is implemented. This allows a kernel to be build
       entirely on AFS.

  Note that Pre AFS-3.4 servers are no longer supported, though this can
  be added back if necessary (AFS-3.4 was released in 1998)"

* tag 'afs-next-20171113' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (35 commits)
  afs: Protect call->state changes against signals
  afs: Trace page dirty/clean
  afs: Implement shared-writeable mmap
  afs: Get rid of the afs_writeback record
  afs: Introduce a file-private data record
  afs: Use a dynamic port if 7001 is in use
  afs: Fix directory read/modify race
  afs: Trace the sending of pages
  afs: Trace the initiation and completion of client calls
  afs: Fix documentation on # vs % prefix in mount source specification
  afs: Fix total-length calculation for multiple-page send
  afs: Only progress call state at end of Tx phase from rxrpc callback
  afs: Make use of the YFS service upgrade to fully support IPv6
  afs: Overhaul volume and server record caching and fileserver rotation
  afs: Move server rotation code into its own file
  afs: Add an address list concept
  afs: Overhaul cell database management
  afs: Overhaul permit caching
  afs: Overhaul the callback handling
  afs: Rename struct afs_call server member to cm_server
  ...

1 files changed, 387 insertions, 322 deletions

diff --git a/fs/afs/write.c b/fs/afs/write.c
index 11dd0526b96b..18e46e31523c 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -8,6 +8,7 @@
  * 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>
@@ -16,9 +17,6 @@
 #include <linux/pagevec.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
  */
@@ -29,58 +27,6 @@ int afs_set_page_dirty(struct page *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
- */
-void afs_put_writeback(struct afs_writeback *wb)
-{
-	struct afs_vnode *vnode = wb->vnode;
-
-	_enter("{%d}", wb->usage);
-
-	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);
-}
-
-/*
  * partly or wholly fill a page that's under preparation for writing
  */
 static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
@@ -103,7 +49,7 @@ static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
 	req->pages[0] = page;
 	get_page(page);
 
-	ret = afs_vnode_fetch_data(vnode, key, req);
+	ret = afs_fetch_data(vnode, key, req);
 	afs_put_read(req);
 	if (ret < 0) {
 		if (ret == -ENOENT) {
@@ -125,42 +71,32 @@ 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_SIZE - 1);
-	unsigned to = from + len;
+	struct key *key = afs_file_key(file);
+	unsigned long priv;
+	unsigned f, from = pos & (PAGE_SIZE - 1);
+	unsigned t, to = from + len;
 	pgoff_t index = pos >> PAGE_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);
+	/* We want to store information about how much of a page is altered in
+	 * page->private.
+	 */
+	BUILD_BUG_ON(PAGE_SIZE > 32768 && sizeof(page->private) < 8);
 
 	page = grab_cache_page_write_begin(mapping, index, flags);
-	if (!page) {
-		kfree(candidate);
+	if (!page)
 		return -ENOMEM;
-	}
 
 	if (!PageUptodate(page) && len != PAGE_SIZE) {
 		ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page);
 		if (ret < 0) {
 			unlock_page(page);
 			put_page(page);
-			kfree(candidate);
 			_leave(" = %d [prep]", ret);
 			return ret;
 		}
@@ -171,79 +107,54 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 	*pagep = 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;
+	/* See if this page is already partially written in a way that we can
+	 * merge the new write with.
+	 */
+	t = f = 0;
+	if (PagePrivate(page)) {
+		priv = page_private(page);
+		f = priv & AFS_PRIV_MAX;
+		t = priv >> AFS_PRIV_SHIFT;
+		ASSERTCMP(f, <=, t);
 	}
 
-	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;
-		}
+	if (f != t) {
+		if (to < f || from > t)
+			goto flush_conflicting_write;
+		if (from < f)
+			f = from;
+		if (to > t)
+			t = to;
+	} else {
+		f = from;
+		t = to;
 	}
 
-	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);
+	priv = (unsigned long)t << AFS_PRIV_SHIFT;
+	priv |= f;
+	trace_afs_page_dirty(vnode, tracepoint_string("begin"),
+			     page->index, priv);
 	SetPagePrivate(page);
-	set_page_private(page, (unsigned long) wb);
-	kfree(candidate);
-	_leave(" = 0 [app]");
+	set_page_private(page, priv);
+	_leave(" = 0");
 	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:
+	/* The previous write and this write aren't adjacent or overlapping, so
+	 * flush the page out.
+	 */
+flush_conflicting_write:
 	_debug("flush conflict");
-	if (wb->state == AFS_WBACK_PENDING)
-		wb->state = AFS_WBACK_CONFLICTING;
-	spin_unlock(&vnode->writeback_lock);
-	if (clear_page_dirty_for_io(page)) {
-		ret = afs_write_back_from_locked_page(wb, page);
-		if (ret < 0) {
-			afs_put_writeback(candidate);
-			_leave(" = %d", ret);
-			return ret;
-		}
+	ret = write_one_page(page);
+	if (ret < 0) {
+		_leave(" = %d", ret);
+		return ret;
 	}
 
-	/* the page holds a ref on the writeback record */
-	afs_put_writeback(wb);
-	set_page_private(page, 0);
-	ClearPagePrivate(page);
+	ret = lock_page_killable(page);
+	if (ret < 0) {
+		_leave(" = %d", ret);
+		return ret;
+	}
 	goto try_again;
 }
 
@@ -255,7 +166,7 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 		  struct page *page, void *fsdata)
 {
 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
-	struct key *key = file->private_data;
+	struct key *key = afs_file_key(file);
 	loff_t i_size, maybe_i_size;
 	int ret;
 
@@ -266,11 +177,11 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 
 	i_size = i_size_read(&vnode->vfs_inode);
 	if (maybe_i_size > i_size) {
-		spin_lock(&vnode->writeback_lock);
+		spin_lock(&vnode->wb_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);
+		spin_unlock(&vnode->wb_lock);
 	}
 
 	if (!PageUptodate(page)) {
@@ -299,9 +210,10 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 /*
  * kill all the pages in the given range
  */
-static void afs_kill_pages(struct afs_vnode *vnode, bool error,
+static void afs_kill_pages(struct address_space *mapping,
 			   pgoff_t first, pgoff_t last)
 {
+	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
 	struct pagevec pv;
 	unsigned count, loop;
 
@@ -316,37 +228,157 @@ static void afs_kill_pages(struct afs_vnode *vnode, bool error,
 		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);
+		pv.nr = find_get_pages_contig(mapping, first, count, pv.pages);
 		ASSERTCMP(pv.nr, ==, count);
 
 		for (loop = 0; loop < count; loop++) {
 			struct page *page = pv.pages[loop];
 			ClearPageUptodate(page);
-			if (error)
-				SetPageError(page);
-			if (PageWriteback(page))
-				end_page_writeback(page);
+			SetPageError(page);
+			end_page_writeback(page);
 			if (page->index >= first)
 				first = page->index + 1;
+			lock_page(page);
+			generic_error_remove_page(mapping, page);
 		}
 
 		__pagevec_release(&pv);
-	} while (first < last);
+	} while (first <= last);
 
 	_leave("");
 }
 
 /*
- * synchronously write back the locked page and any subsequent non-locked dirty
- * pages also covered by the same writeback record
+ * Redirty all the pages in a given range.
+ */
+static void afs_redirty_pages(struct writeback_control *wbc,
+			      struct address_space *mapping,
+			      pgoff_t first, pgoff_t last)
+{
+	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
+	struct pagevec pv;
+	unsigned count, loop;
+
+	_enter("{%x:%u},%lx-%lx",
+	       vnode->fid.vid, vnode->fid.vnode, first, last);
+
+	pagevec_init(&pv);
+
+	do {
+		_debug("redirty %lx-%lx", first, last);
+
+		count = last - first + 1;
+		if (count > PAGEVEC_SIZE)
+			count = PAGEVEC_SIZE;
+		pv.nr = find_get_pages_contig(mapping, first, count, pv.pages);
+		ASSERTCMP(pv.nr, ==, count);
+
+		for (loop = 0; loop < count; loop++) {
+			struct page *page = pv.pages[loop];
+
+			redirty_page_for_writepage(wbc, page);
+			end_page_writeback(page);
+			if (page->index >= first)
+				first = page->index + 1;
+		}
+
+		__pagevec_release(&pv);
+	} while (first <= last);
+
+	_leave("");
+}
+
+/*
+ * write to a file
+ */
+static int afs_store_data(struct address_space *mapping,
+			  pgoff_t first, pgoff_t last,
+			  unsigned offset, unsigned to)
+{
+	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
+	struct afs_fs_cursor fc;
+	struct afs_wb_key *wbk = NULL;
+	struct list_head *p;
+	int ret = -ENOKEY, ret2;
+
+	_enter("%s{%x:%u.%u},%lx,%lx,%x,%x",
+	       vnode->volume->name,
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique,
+	       first, last, offset, to);
+
+	spin_lock(&vnode->wb_lock);
+	p = vnode->wb_keys.next;
+
+	/* Iterate through the list looking for a valid key to use. */
+try_next_key:
+	while (p != &vnode->wb_keys) {
+		wbk = list_entry(p, struct afs_wb_key, vnode_link);
+		_debug("wbk %u", key_serial(wbk->key));
+		ret2 = key_validate(wbk->key);
+		if (ret2 == 0)
+			goto found_key;
+		if (ret == -ENOKEY)
+			ret = ret2;
+		p = p->next;
+	}
+
+	spin_unlock(&vnode->wb_lock);
+	afs_put_wb_key(wbk);
+	_leave(" = %d [no keys]", ret);
+	return ret;
+
+found_key:
+	refcount_inc(&wbk->usage);
+	spin_unlock(&vnode->wb_lock);
+
+	_debug("USE WB KEY %u", key_serial(wbk->key));
+
+	ret = -ERESTARTSYS;
+	if (afs_begin_vnode_operation(&fc, vnode, wbk->key)) {
+		while (afs_select_fileserver(&fc)) {
+			fc.cb_break = vnode->cb_break + vnode->cb_s_break;
+			afs_fs_store_data(&fc, mapping, first, last, offset, to);
+		}
+
+		afs_check_for_remote_deletion(&fc, fc.vnode);
+		afs_vnode_commit_status(&fc, vnode, fc.cb_break);
+		ret = afs_end_vnode_operation(&fc);
+	}
+
+	switch (ret) {
+	case -EACCES:
+	case -EPERM:
+	case -ENOKEY:
+	case -EKEYEXPIRED:
+	case -EKEYREJECTED:
+	case -EKEYREVOKED:
+		_debug("next");
+		spin_lock(&vnode->wb_lock);
+		p = wbk->vnode_link.next;
+		afs_put_wb_key(wbk);
+		goto try_next_key;
+	}
+
+	afs_put_wb_key(wbk);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Synchronously write back the locked page and any subsequent non-locked dirty
+ * pages.
  */
-static int afs_write_back_from_locked_page(struct afs_writeback *wb,
-					   struct page *primary_page)
+static int afs_write_back_from_locked_page(struct address_space *mapping,
+					   struct writeback_control *wbc,
+					   struct page *primary_page,
+					   pgoff_t final_page)
 {
+	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
 	struct page *pages[8], *page;
-	unsigned long count;
-	unsigned n, offset, to;
+	unsigned long count, priv;
+	unsigned n, offset, to, f, t;
 	pgoff_t start, first, last;
 	int loop, ret;
 
@@ -356,20 +388,33 @@ static int afs_write_back_from_locked_page(struct afs_writeback *wb,
 	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 */
+	/* Find all consecutive lockable dirty pages that have contiguous
+	 * written regions, 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)
+	priv = page_private(primary_page);
+	offset = priv & AFS_PRIV_MAX;
+	to = priv >> AFS_PRIV_SHIFT;
+	trace_afs_page_dirty(vnode, tracepoint_string("store"),
+			     primary_page->index, priv);
+
+	WARN_ON(offset == to);
+	if (offset == to)
+		trace_afs_page_dirty(vnode, tracepoint_string("WARN"),
+				     primary_page->index, priv);
+
+	if (start >= final_page || to < PAGE_SIZE)
 		goto no_more;
+
 	start++;
 	do {
 		_debug("more %lx [%lx]", start, count);
-		n = wb->last - start + 1;
+		n = final_page - 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);
+		n = find_get_pages_contig(mapping, start, ARRAY_SIZE(pages), pages);
 		_debug("fgpc %u", n);
 		if (n == 0)
 			goto no_more;
@@ -381,16 +426,30 @@ static int afs_write_back_from_locked_page(struct afs_writeback *wb,
 		}
 
 		for (loop = 0; loop < n; loop++) {
+			if (to != PAGE_SIZE)
+				break;
 			page = pages[loop];
-			if (page->index > wb->last)
+			if (page->index > final_page)
 				break;
 			if (!trylock_page(page))
 				break;
-			if (!PageDirty(page) ||
-			    page_private(page) != (unsigned long) wb) {
+			if (!PageDirty(page) || PageWriteback(page)) {
 				unlock_page(page);
 				break;
 			}
+
+			priv = page_private(page);
+			f = priv & AFS_PRIV_MAX;
+			t = priv >> AFS_PRIV_SHIFT;
+			if (f != 0) {
+				unlock_page(page);
+				break;
+			}
+			to = t;
+
+			trace_afs_page_dirty(vnode, tracepoint_string("store+"),
+					     page->index, priv);
+
 			if (!clear_page_dirty_for_io(page))
 				BUG();
 			if (test_set_page_writeback(page))
@@ -406,50 +465,55 @@ static int afs_write_back_from_locked_page(struct afs_writeback *wb,
 		}
 
 		start += loop;
-	} while (start <= wb->last && count < 65536);
+	} while (start <= final_page && 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 */
+	/* We now have a contiguous set of dirty pages, each with writeback
+	 * set; the first page is still locked at this point, but all the rest
+	 * have been unlocked.
+	 */
+	unlock_page(primary_page);
+
 	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:
-			mapping_set_error(wb->vnode->vfs_inode.i_mapping, -ENOSPC);
-			break;
-		case -EROFS:
-		case -EIO:
-		case -EREMOTEIO:
-		case -EFBIG:
-		case -ENOENT:
-		case -ENOMEDIUM:
-		case -ENXIO:
-			afs_kill_pages(wb->vnode, true, first, last);
-			mapping_set_error(wb->vnode->vfs_inode.i_mapping, -EIO);
-			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 = afs_store_data(mapping, first, last, offset, to);
+	switch (ret) {
+	case 0:
 		ret = count;
+		break;
+
+	default:
+		pr_notice("kAFS: Unexpected error from FS.StoreData %d\n", ret);
+		/* Fall through */
+	case -EACCES:
+	case -EPERM:
+	case -ENOKEY:
+	case -EKEYEXPIRED:
+	case -EKEYREJECTED:
+	case -EKEYREVOKED:
+		afs_redirty_pages(wbc, mapping, first, last);
+		mapping_set_error(mapping, ret);
+		break;
+
+	case -EDQUOT:
+	case -ENOSPC:
+		afs_redirty_pages(wbc, mapping, first, last);
+		mapping_set_error(mapping, -ENOSPC);
+		break;
+
+	case -EROFS:
+	case -EIO:
+	case -EREMOTEIO:
+	case -EFBIG:
+	case -ENOENT:
+	case -ENOMEDIUM:
+	case -ENXIO:
+		afs_kill_pages(mapping, first, last);
+		mapping_set_error(mapping, ret);
+		break;
 	}
 
 	_leave(" = %d", ret);
@@ -462,16 +526,12 @@ no_more:
  */
 int afs_writepage(struct page *page, struct writeback_control *wbc)
 {
-	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);
+	ret = afs_write_back_from_locked_page(page->mapping, wbc, page,
+					      wbc->range_end >> PAGE_SHIFT);
 	if (ret < 0) {
 		_leave(" = %d", ret);
 		return 0;
@@ -490,7 +550,6 @@ 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;
 
@@ -509,7 +568,12 @@ static int afs_writepages_region(struct address_space *mapping,
 		 * (changing page->mapping to NULL), or even swizzled back from
 		 * swapper_space to tmpfs file mapping
 		 */
-		lock_page(page);
+		ret = lock_page_killable(page);
+		if (ret < 0) {
+			put_page(page);
+			_leave(" = %d", ret);
+			return ret;
+		}
 
 		if (page->mapping != mapping || !PageDirty(page)) {
 			unlock_page(page);
@@ -525,17 +589,9 @@ static int afs_writepages_region(struct address_space *mapping,
 			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);
-
 		if (!clear_page_dirty_for_io(page))
 			BUG();
-		ret = afs_write_back_from_locked_page(wb, page);
-		unlock_page(page);
+		ret = afs_write_back_from_locked_page(mapping, wbc, page, end);
 		put_page(page);
 		if (ret < 0) {
 			_leave(" = %d", ret);
@@ -591,17 +647,14 @@ int afs_writepages(struct address_space *mapping,
  */
 void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call)
 {
-	struct afs_writeback *wb = call->wb;
 	struct pagevec pv;
+	unsigned long priv;
 	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);
 
 	do {
@@ -610,35 +663,22 @@ void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call)
 		count = last - first + 1;
 		if (count > PAGEVEC_SIZE)
 			count = PAGEVEC_SIZE;
-		pv.nr = find_get_pages_contig(call->mapping, first, count,
-					      pv.pages);
+		pv.nr = find_get_pages_contig(vnode->vfs_inode.i_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;
+			priv = page_private(pv.pages[loop]);
+			trace_afs_page_dirty(vnode, tracepoint_string("clear"),
+					     pv.pages[loop]->index, priv);
+			set_page_private(pv.pages[loop], 0);
+			end_page_writeback(pv.pages[loop]);
 		}
-		spin_unlock(&vnode->writeback_lock);
 		first += count;
-		if (free_wb) {
-			afs_free_writeback(wb);
-			wb = NULL;
-		}
-
 		__pagevec_release(&pv);
 	} while (first <= last);
 
+	afs_prune_wb_keys(vnode);
 	_leave("");
 }
 
@@ -670,28 +710,6 @@ ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from)
 }
 
 /*
- * flush the vnode to the fileserver
- */
-int afs_writeback_all(struct afs_vnode *vnode)
-{
-	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,
-	};
-	int ret;
-
-	_enter("");
-
-	ret = mapping->a_ops->writepages(mapping, &wbc);
-	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
-
-	_leave(" = %d", ret);
-	return ret;
-}
-
-/*
  * flush any dirty pages for this process, and check for write errors.
  * - the return status from this call provides a reliable indication of
  *   whether any write errors occurred for this process.
@@ -699,61 +717,13 @@ int afs_writeback_all(struct afs_vnode *vnode)
 int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 {
 	struct inode *inode = file_inode(file);
-	struct afs_writeback *wb, *xwb;
 	struct afs_vnode *vnode = AFS_FS_I(inode);
-	int ret;
 
 	_enter("{%x:%u},{n=%pD},%d",
 	       vnode->fid.vid, vnode->fid.vnode, file,
 	       datasync);
 
-	ret = file_write_and_wait_range(file, start, end);
-	if (ret)
-		return ret;
-	inode_lock(inode);
-
-	/* 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:
-	inode_unlock(inode);
-	return ret;
+	return file_write_and_wait_range(file, start, end);
 }
 
 /*
@@ -774,19 +744,114 @@ int afs_flush(struct file *file, fl_owner_t id)
  * 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)
+int 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;
+	struct inode *inode = file_inode(file);
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+	unsigned long priv;
 
 	_enter("{{%x:%u}},{%lx}",
-	       vnode->fid.vid, vnode->fid.vnode, page->index);
+	       vnode->fid.vid, vnode->fid.vnode, vmf->page->index);
+
+	sb_start_pagefault(inode->i_sb);
 
-	/* wait for the page to be written to the cache before we allow it to
-	 * be modified */
+	/* Wait for the page to be written to the cache before we allow it to
+	 * be modified.  We then assume the entire page will need writing back.
+	 */
 #ifdef CONFIG_AFS_FSCACHE
-	fscache_wait_on_page_write(vnode->cache, page);
+	fscache_wait_on_page_write(vnode->cache, vmf->page);
 #endif
 
-	_leave(" = 0");
-	return 0;
+	if (PageWriteback(vmf->page) &&
+	    wait_on_page_bit_killable(vmf->page, PG_writeback) < 0)
+		return VM_FAULT_RETRY;
+
+	if (lock_page_killable(vmf->page) < 0)
+		return VM_FAULT_RETRY;
+
+	/* We mustn't change page->private until writeback is complete as that
+	 * details the portion of the page we need to write back and we might
+	 * need to redirty the page if there's a problem.
+	 */
+	wait_on_page_writeback(vmf->page);
+
+	priv = (unsigned long)PAGE_SIZE << AFS_PRIV_SHIFT; /* To */
+	priv |= 0; /* From */
+	trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"),
+			     vmf->page->index, priv);
+	SetPagePrivate(vmf->page);
+	set_page_private(vmf->page, priv);
+
+	sb_end_pagefault(inode->i_sb);
+	return VM_FAULT_LOCKED;
+}
+
+/*
+ * 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;
+
+	/* Discard unused keys */
+	spin_lock(&vnode->wb_lock);
+
+	if (!mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_WRITEBACK) &&
+	    !mapping_tagged(&vnode->vfs_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);
+	}
+}
+
+/*
+ * Clean up a page during invalidation.
+ */
+int afs_launder_page(struct page *page)
+{
+	struct address_space *mapping = page->mapping;
+	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
+	unsigned long priv;
+	unsigned int f, t;
+	int ret = 0;
+
+	_enter("{%lx}", page->index);
+
+	priv = page_private(page);
+	if (clear_page_dirty_for_io(page)) {
+		f = 0;
+		t = PAGE_SIZE;
+		if (PagePrivate(page)) {
+			f = priv & AFS_PRIV_MAX;
+			t = priv >> AFS_PRIV_SHIFT;
+		}
+
+		trace_afs_page_dirty(vnode, tracepoint_string("launder"),
+				     page->index, priv);
+		ret = afs_store_data(mapping, page->index, page->index, t, f);
+	}
+
+	trace_afs_page_dirty(vnode, tracepoint_string("laundered"),
+			     page->index, priv);
+	set_page_private(page, 0);
+	ClearPagePrivate(page);
+
+#ifdef CONFIG_AFS_FSCACHE
+	if (PageFsCache(page)) {
+		fscache_wait_on_page_write(vnode->cache, page);
+		fscache_uncache_page(vnode->cache, page);
+	}
+#endif
+	return ret;
 }