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

commit 4595a298d5563cf76c1d852970f162051fd1a7a6 upstream.

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: Shida Zhang zhangshida@kylinos.cn --- fs/iomap.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/fs/iomap.c b/fs/iomap.c index ac7b2152c3ad..04e82b6bd9bf 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -109,6 +109,7 @@ 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; @@ -118,6 +119,8 @@ 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