linux-ext4 - [PATCH 3/6] iomap: mark newly allocated buffer heads as new

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Date:   Thu, 14 Jun 2018 14:04:54 +0200
From:   Christoph Hellwig <hch@....de>
To:     Andreas Gruenbacher <agruenba@...hat.com>,
        linux-xfs@...r.kernel.org
Cc:     Dan Williams <dan.j.williams@...el.com>,
        linux-fsdevel@...r.kernel.org, cluster-devel@...hat.com,
        linux-ext4@...r.kernel.org
Subject: [PATCH 3/6] iomap: mark newly allocated buffer heads as new

From: Andreas Gruenbacher <agruenba@...hat.com>

In iomap_to_bh, not only mark buffer heads in IOMAP_UNWRITTEN maps as
new, but also buffer heads in IOMAP_MAPPED maps with the IOMAP_F_NEW
flag set.  This will be used by filesystems like gfs2, which allocate
blocks in iomap->begin.

Minor corrections to the comment for IOMAP_UNWRITTEN maps.

Signed-off-by: Andreas Gruenbacher <agruenba@...hat.com>
Signed-off-by: Christoph Hellwig <hch@....de>
---
 fs/buffer.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index aba2a948b235..c8c2b7d8b8d6 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1900,15 +1900,16 @@ iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh,
 		break;
 	case IOMAP_UNWRITTEN:
 		/*
-		 * For unwritten regions, we always need to ensure that
-		 * sub-block writes cause the regions in the block we are not
-		 * writing to are zeroed. Set the buffer as new to ensure this.
+		 * For unwritten regions, we always need to ensure that regions
+		 * in the block we are not writing to are zeroed. Mark the
+		 * buffer as new to ensure this.
 		 */
 		set_buffer_new(bh);
 		set_buffer_unwritten(bh);
 		/* FALLTHRU */
 	case IOMAP_MAPPED:
-		if (offset >= i_size_read(inode))
+		if ((iomap->flags & IOMAP_F_NEW) ||
+		    offset >= i_size_read(inode))
 			set_buffer_new(bh);
 		bh->b_blocknr = (iomap->addr + offset - iomap->offset) >>
 				inode->i_blkbits;
-- 
2.17.1