1 files changed, 127 insertions, 46 deletions

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 139e495b0cd3..392833ccc9c6 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1187,11 +1187,18 @@ __xfs_get_blocks(
 						       &imap, nimaps);
 			if (error)
 				return -error;
+			new = 1;
 		} else {
 			/*
 			 * Delalloc reservations do not require a transaction,
-			 * we can go on without dropping the lock here.
+			 * we can go on without dropping the lock here. If we
+			 * are allocating a new delalloc block, make sure that
+			 * we set the new flag so that we mark the buffer new so
+			 * that we know that it is newly allocated if the write
+			 * fails.
 			 */
+			if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
+				new = 1;
 			error = xfs_iomap_write_delay(ip, offset, size, &imap);
 			if (error)
 				goto out_unlock;
@@ -1408,52 +1415,91 @@ out_destroy_ioend:
 	return ret;
 }
 
+/*
+ * Punch out the delalloc blocks we have already allocated.
+ *
+ * Don't bother with xfs_setattr given that nothing can have made it to disk yet
+ * as the page is still locked at this point.
+ */
+STATIC void
+xfs_vm_kill_delalloc_range(
+	struct inode		*inode,
+	loff_t			start,
+	loff_t			end)
+{
+	struct xfs_inode	*ip = XFS_I(inode);
+	xfs_fileoff_t		start_fsb;
+	xfs_fileoff_t		end_fsb;
+	int			error;
+
+	start_fsb = XFS_B_TO_FSB(ip->i_mount, start);
+	end_fsb = XFS_B_TO_FSB(ip->i_mount, end);
+	if (end_fsb <= start_fsb)
+		return;
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
+						end_fsb - start_fsb);
+	if (error) {
+		/* something screwed, just bail */
+		if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
+			xfs_alert(ip->i_mount,
+		"xfs_vm_write_failed: unable to clean up ino %lld",
+					ip->i_ino);
+		}
+	}
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+}
+
 STATIC void
 xfs_vm_write_failed(
-	struct address_space	*mapping,
-	loff_t			to)
+	struct inode		*inode,
+	struct page		*page,
+	loff_t			pos,
+	unsigned		len)
 {
-	struct inode		*inode = mapping->host;
+	loff_t			block_offset = pos & PAGE_MASK;
+	loff_t			block_start;
+	loff_t			block_end;
+	loff_t			from = pos & (PAGE_CACHE_SIZE - 1);
+	loff_t			to = from + len;
+	struct buffer_head	*bh, *head;
 
-	if (to > inode->i_size) {
-		/*
-		 * Punch out the delalloc blocks we have already allocated.
-		 *
-		 * Don't bother with xfs_setattr given that nothing can have
-		 * made it to disk yet as the page is still locked at this
-		 * point.
-		 */
-		struct xfs_inode	*ip = XFS_I(inode);
-		xfs_fileoff_t		start_fsb;
-		xfs_fileoff_t		end_fsb;
-		int			error;
+	ASSERT(block_offset + from == pos);
 
-		truncate_pagecache(inode, to, inode->i_size);
+	head = page_buffers(page);
+	block_start = 0;
+	for (bh = head; bh != head || !block_start;
+	     bh = bh->b_this_page, block_start = block_end,
+				   block_offset += bh->b_size) {
+		block_end = block_start + bh->b_size;
 
-		/*
-		 * Check if there are any blocks that are outside of i_size
-		 * that need to be trimmed back.
-		 */
-		start_fsb = XFS_B_TO_FSB(ip->i_mount, inode->i_size);
-		end_fsb = XFS_B_TO_FSB(ip->i_mount, to);
-		if (end_fsb <= start_fsb)
-			return;
-
-		xfs_ilock(ip, XFS_ILOCK_EXCL);
-		error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
-							end_fsb - start_fsb);
-		if (error) {
-			/* something screwed, just bail */
-			if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
-				xfs_alert(ip->i_mount,
-			"xfs_vm_write_failed: unable to clean up ino %lld",
-						ip->i_ino);
-			}
-		}
-		xfs_iunlock(ip, XFS_ILOCK_EXCL);
+		/* skip buffers before the write */
+		if (block_end <= from)
+			continue;
+
+		/* if the buffer is after the write, we're done */
+		if (block_start >= to)
+			break;
+
+		if (!buffer_delay(bh))
+			continue;
+
+		if (!buffer_new(bh) && block_offset < i_size_read(inode))
+			continue;
+
+		xfs_vm_kill_delalloc_range(inode, block_offset,
+					   block_offset + bh->b_size);
 	}
+
 }
 
+/*
+ * This used to call block_write_begin(), but it unlocks and releases the page
+ * on error, and we need that page to be able to punch stale delalloc blocks out
+ * on failure. hence we copy-n-waste it here and call xfs_vm_write_failed() at
+ * the appropriate point.
+ */
 STATIC int
 xfs_vm_write_begin(
 	struct file		*file,
@@ -1464,15 +1510,40 @@ xfs_vm_write_begin(
 	struct page		**pagep,
 	void			**fsdata)
 {
-	int			ret;
+	pgoff_t			index = pos >> PAGE_CACHE_SHIFT;
+	struct page		*page;
+	int			status;
 
-	ret = block_write_begin(mapping, pos, len, flags | AOP_FLAG_NOFS,
-				pagep, xfs_get_blocks);
-	if (unlikely(ret))
-		xfs_vm_write_failed(mapping, pos + len);
-	return ret;
+	ASSERT(len <= PAGE_CACHE_SIZE);
+
+	page = grab_cache_page_write_begin(mapping, index,
+					   flags | AOP_FLAG_NOFS);
+	if (!page)
+		return -ENOMEM;
+
+	status = __block_write_begin(page, pos, len, xfs_get_blocks);
+	if (unlikely(status)) {
+		struct inode	*inode = mapping->host;
+
+		xfs_vm_write_failed(inode, page, pos, len);
+		unlock_page(page);
+
+		if (pos + len > i_size_read(inode))
+			truncate_pagecache(inode, pos + len, i_size_read(inode));
+
+		page_cache_release(page);
+		page = NULL;
+	}
+
+	*pagep = page;
+	return status;
 }
 
+/*
+ * On failure, we only need to kill delalloc blocks beyond EOF because they
+ * will never be written. For blocks within EOF, generic_write_end() zeros them
+ * so they are safe to leave alone and be written with all the other valid data.
+ */
 STATIC int
 xfs_vm_write_end(
 	struct file		*file,
@@ -1485,9 +1556,19 @@ xfs_vm_write_end(
 {
 	int			ret;
 
+	ASSERT(len <= PAGE_CACHE_SIZE);
+
 	ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
-	if (unlikely(ret < len))
-		xfs_vm_write_failed(mapping, pos + len);
+	if (unlikely(ret < len)) {
+		struct inode	*inode = mapping->host;
+		size_t		isize = i_size_read(inode);
+		loff_t		to = pos + len;
+
+		if (to > isize) {
+			truncate_pagecache(inode, to, isize);
+			xfs_vm_kill_delalloc_range(inode, isize, to);
+		}
+	}
 	return ret;
 }