[PATCH 14/15] gfs2: don't use buffer_heads in gfs2_allocate_page_backing

Christoph Hellwig
2019-07-01T21:56:34Z

Rewrite gfs2_allocate_page_backing to call gfs2_iomap_get_alloc and
operate on struct iomap directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/gfs2/file.c | 33 ++++++++++++++++-----------------
1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 282a4aaab900..8c72e4cecd89 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -379,31 +379,30 @@ static void gfs2_size_hint(struct file *filep, loff_t offset, size_t size)
}

/**
- * gfs2_allocate_page_backing - Use bmap to allocate blocks
+ * gfs2_allocate_page_backing - Allocate blocks for a write fault
* @page: The (locked) page to allocate backing for
*
- * We try to allocate all the blocks required for the page in
- * one go. This might fail for various reasons, so we keep
- * trying until all the blocks to back this page are allocated.
- * If some of the blocks are already allocated, thats ok too.
+ * We try to allocate all the blocks required for the page in one go. This
+ * might fail for various reasons, so we keep trying until all the blocks to
+ * back this page are allocated. If some of the blocks are already allocated,
+ * that is ok too.
*/
-
static int gfs2_allocate_page_backing(struct page *page)
{
- struct inode *inode = page->mapping->host;
- struct buffer_head bh;
- unsigned long size = PAGE_SIZE;
- u64 lblock = page->index << (PAGE_SHIFT - inode->i_blkbits);
+ u64 pos = page_offset(page);
+ u64 size = PAGE_SIZE;

do {
- bh.b_state = 0;
- bh.b_size = size;
- gfs2_block_map(inode, lblock, &bh, 1);
- if (!buffer_mapped(&bh))
+ struct iomap iomap = { };
+
+ if (gfs2_iomap_get_alloc(page->mapping->host, pos, 1, &iomap))
return -EIO;
- size -= bh.b_size;
- lblock += (bh.b_size >> inode->i_blkbits);
- } while(size > 0);
+
+ iomap.length = min(iomap.length, size);
+ size -= iomap.length;
+ pos += iomap.length;
+ } while (size > 0);
+
return 0;
}

--
2.20.1