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

Christoph Hellwig
2018-06-14T12:04:54Z

From: Andreas Gruenbacher <agruenba@redhat.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@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.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