1 files changed, 59 insertions, 51 deletions

diff --git a/fs/afs/write.c b/fs/afs/write.c
index da12abd6db21..c9195fc67fd8 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -76,7 +76,7 @@ static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
  */
 int afs_write_begin(struct file *file, struct address_space *mapping,
 		    loff_t pos, unsigned len, unsigned flags,
-		    struct page **pagep, void **fsdata)
+		    struct page **_page, void **fsdata)
 {
 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
 	struct page *page;
@@ -90,11 +90,6 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 	_enter("{%llx:%llu},{%lx},%u,%u",
 	       vnode->fid.vid, vnode->fid.vnode, index, from, to);
 
-	/* 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)
 		return -ENOMEM;
@@ -110,9 +105,6 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 		SetPageUptodate(page);
 	}
 
-	/* page won't leak in error case: it eventually gets cleaned off LRU */
-	*pagep = page;
-
 try_again:
 	/* See if this page is already partially written in a way that we can
 	 * merge the new write with.
@@ -120,8 +112,8 @@ try_again:
 	t = f = 0;
 	if (PagePrivate(page)) {
 		priv = page_private(page);
-		f = priv & AFS_PRIV_MAX;
-		t = priv >> AFS_PRIV_SHIFT;
+		f = afs_page_dirty_from(priv);
+		t = afs_page_dirty_to(priv);
 		ASSERTCMP(f, <=, t);
 	}
 
@@ -138,21 +130,9 @@ try_again:
 		if (!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags) &&
 		    (to < f || from > t))
 			goto flush_conflicting_write;
-		if (from < f)
-			f = from;
-		if (to > t)
-			t = to;
-	} else {
-		f = from;
-		t = to;
 	}
 
-	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, priv);
+	*_page = page;
 	_leave(" = 0");
 	return 0;
 
@@ -162,17 +142,18 @@ try_again:
 flush_conflicting_write:
 	_debug("flush conflict");
 	ret = write_one_page(page);
-	if (ret < 0) {
-		_leave(" = %d", ret);
-		return ret;
-	}
+	if (ret < 0)
+		goto error;
 
 	ret = lock_page_killable(page);
-	if (ret < 0) {
-		_leave(" = %d", ret);
-		return ret;
-	}
+	if (ret < 0)
+		goto error;
 	goto try_again;
+
+error:
+	put_page(page);
+	_leave(" = %d", ret);
+	return ret;
 }
 
 /*
@@ -184,12 +165,18 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 {
 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
 	struct key *key = afs_file_key(file);
+	unsigned long priv;
+	unsigned int f, from = pos & (PAGE_SIZE - 1);
+	unsigned int t, to = from + copied;
 	loff_t i_size, maybe_i_size;
-	int ret;
+	int ret = 0;
 
 	_enter("{%llx:%llu},{%lx}",
 	       vnode->fid.vid, vnode->fid.vnode, page->index);
 
+	if (copied == 0)
+		goto out;
+
 	maybe_i_size = pos + copied;
 
 	i_size = i_size_read(&vnode->vfs_inode);
@@ -215,6 +202,25 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 		SetPageUptodate(page);
 	}
 
+	if (PagePrivate(page)) {
+		priv = page_private(page);
+		f = afs_page_dirty_from(priv);
+		t = afs_page_dirty_to(priv);
+		if (from < f)
+			f = from;
+		if (to > t)
+			t = to;
+		priv = afs_page_dirty(f, t);
+		set_page_private(page, priv);
+		trace_afs_page_dirty(vnode, tracepoint_string("dirty+"),
+				     page->index, priv);
+	} else {
+		priv = afs_page_dirty(from, to);
+		attach_page_private(page, (void *)priv);
+		trace_afs_page_dirty(vnode, tracepoint_string("dirty"),
+				     page->index, priv);
+	}
+
 	set_page_dirty(page);
 	if (PageDirty(page))
 		_debug("dirtied");
@@ -334,10 +340,9 @@ static void afs_pages_written_back(struct afs_vnode *vnode,
 		ASSERTCMP(pv.nr, ==, count);
 
 		for (loop = 0; loop < count; loop++) {
-			priv = page_private(pv.pages[loop]);
+			priv = (unsigned long)detach_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]);
 		}
 		first += count;
@@ -396,7 +401,8 @@ static void afs_store_data_success(struct afs_operation *op)
 	op->ctime = op->file[0].scb.status.mtime_client;
 	afs_vnode_commit_status(op, &op->file[0]);
 	if (op->error == 0) {
-		afs_pages_written_back(vnode, op->store.first, op->store.last);
+		if (!op->store.laundering)
+			afs_pages_written_back(vnode, op->store.first, op->store.last);
 		afs_stat_v(vnode, n_stores);
 		atomic_long_add((op->store.last * PAGE_SIZE + op->store.last_to) -
 				(op->store.first * PAGE_SIZE + op->store.first_offset),
@@ -415,7 +421,7 @@ static const struct afs_operation_ops afs_store_data_operation = {
  */
 static int afs_store_data(struct address_space *mapping,
 			  pgoff_t first, pgoff_t last,
-			  unsigned offset, unsigned to)
+			  unsigned offset, unsigned to, bool laundering)
 {
 	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
 	struct afs_operation *op;
@@ -448,6 +454,7 @@ static int afs_store_data(struct address_space *mapping,
 	op->store.last = last;
 	op->store.first_offset = offset;
 	op->store.last_to = to;
+	op->store.laundering = laundering;
 	op->mtime = vnode->vfs_inode.i_mtime;
 	op->flags |= AFS_OPERATION_UNINTR;
 	op->ops = &afs_store_data_operation;
@@ -509,8 +516,8 @@ static int afs_write_back_from_locked_page(struct address_space *mapping,
 	 */
 	start = primary_page->index;
 	priv = page_private(primary_page);
-	offset = priv & AFS_PRIV_MAX;
-	to = priv >> AFS_PRIV_SHIFT;
+	offset = afs_page_dirty_from(priv);
+	to = afs_page_dirty_to(priv);
 	trace_afs_page_dirty(vnode, tracepoint_string("store"),
 			     primary_page->index, priv);
 
@@ -555,8 +562,8 @@ static int afs_write_back_from_locked_page(struct address_space *mapping,
 			}
 
 			priv = page_private(page);
-			f = priv & AFS_PRIV_MAX;
-			t = priv >> AFS_PRIV_SHIFT;
+			f = afs_page_dirty_from(priv);
+			t = afs_page_dirty_to(priv);
 			if (f != 0 &&
 			    !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) {
 				unlock_page(page);
@@ -601,7 +608,7 @@ no_more:
 	if (end > i_size)
 		to = i_size & ~PAGE_MASK;
 
-	ret = afs_store_data(mapping, first, last, offset, to);
+	ret = afs_store_data(mapping, first, last, offset, to, false);
 	switch (ret) {
 	case 0:
 		ret = count;
@@ -857,12 +864,14 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
 	 */
 	wait_on_page_writeback(vmf->page);
 
-	priv = (unsigned long)PAGE_SIZE << AFS_PRIV_SHIFT; /* To */
-	priv |= 0; /* From */
+	priv = afs_page_dirty(0, PAGE_SIZE);
+	priv = afs_page_dirty_mmapped(priv);
 	trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"),
 			     vmf->page->index, priv);
-	SetPagePrivate(vmf->page);
-	set_page_private(vmf->page, priv);
+	if (PagePrivate(vmf->page))
+		set_page_private(vmf->page, priv);
+	else
+		attach_page_private(vmf->page, (void *)priv);
 	file_update_time(file);
 
 	sb_end_pagefault(inode->i_sb);
@@ -915,19 +924,18 @@ int afs_launder_page(struct page *page)
 		f = 0;
 		t = PAGE_SIZE;
 		if (PagePrivate(page)) {
-			f = priv & AFS_PRIV_MAX;
-			t = priv >> AFS_PRIV_SHIFT;
+			f = afs_page_dirty_from(priv);
+			t = afs_page_dirty_to(priv);
 		}
 
 		trace_afs_page_dirty(vnode, tracepoint_string("launder"),
 				     page->index, priv);
-		ret = afs_store_data(mapping, page->index, page->index, t, f);
+		ret = afs_store_data(mapping, page->index, page->index, t, f, true);
 	}
 
+	priv = (unsigned long)detach_page_private(page);
 	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)) {