[PATCH 5.4 48/84] iomap: Set all uptodate bits for an Uptodate page

Greg Kroah-Hartman
2024-02-27T14:25:03Z

From: Matthew Wilcox (Oracle) <willy@infradead.org>

[ Upstream commit 4595a298d5563cf76c1d852970f162051fd1a7a6 ]

For filesystems with block size < page size, we need to set all the
per-block uptodate bits if the page was already uptodate at the time
we create the per-block metadata. This can happen if the page is
invalidated (eg by a write to drop_caches) but ultimately not removed
from the page cache.

This is a data corruption issue as page writeback skips blocks which
are marked !uptodate.

Fixes: 9dc55f1389f9 ("iomap: add support for sub-pagesize buffered I/O without buffer heads")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: Qian Cai <cai@redhat.com>
Cc: Brian Foster <bfoster@redhat.com>
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/iomap/buffered-io.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 53cd7b2bb580b..c28ba474a25e7 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -23,6 +23,7 @@ static struct iomap_page *
iomap_page_create(struct inode *inode, struct page *page)
{
struct iomap_page *iop = to_iomap_page(page);
+ unsigned int nr_blocks = PAGE_SIZE / i_blocksize(inode);

if (iop || i_blocksize(inode) == PAGE_SIZE)
return iop;
@@ -32,6 +33,8 @@ iomap_page_create(struct inode *inode, struct page *page)
atomic_set(&iop->write_count, 0);
spin_lock_init(&iop->uptodate_lock);
bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
+ if (PageUptodate(page))
+ bitmap_fill(iop->uptodate, nr_blocks);

/*
* migrate_page_move_mapping() assumes that pages with private data have
--
2.43.0