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@xxxxxxxxxxxxx>
Reported-by: Qian Cai <cai@xxxxxxxxxx>
Cc: Brian Foster <bfoster@xxxxxxxxxx>
---
fs/iomap/buffered-io.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 8b6cca7e34e4..8180061b9e16 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -60,6 +60,8 @@ iomap_page_create(struct inode *inode, struct page *page)
iop = kzalloc(struct_size(iop, uptodate, BITS_TO_LONGS(nr_blocks)),
GFP_NOFS | __GFP_NOFAIL);
spin_lock_init(&iop->uptodate_lock);
+ if (PageUptodate(page))
+ bitmap_fill(iop->uptodate, nr_blocks);
attach_page_private(page, iop);
return iop;
}
--
2.28.0
