fs/ntfs3: Initialize new folios before use

KMSAN reports an uninitialized value in longest_match_std(), invoked
from ntfs_compress_write(). When new folios are allocated without being
marked uptodate and ni_read_frame() is skipped because the caller expects
the frame to be completely overwritten, some reserved folios may remain
only partially filled, leaving the rest memory uninitialized.

Fixes: 584f60b ("ntfs3: Convert ntfs_get_frame_pages() to use a folio")
Tested-by: syzbot+08d8956768c96a2c52cf@syzkaller.appspotmail.com
Reported-by: syzbot+08d8956768c96a2c52cf@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=08d8956768c96a2c52cf

Signed-off-by: Bartlomiej Kubik <kubik.bartlomiej@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Author: Bartekkubik

fs/ntfs3/file.c

@@ -995,7 +995,7 @@ static int ntfs_get_frame_pages(struct address_space *mapping, pgoff_t index,
 
 		folio = __filemap_get_folio(mapping, index,
 					    FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
-					    gfp_mask);
+					    gfp_mask | __GFP_ZERO);
 		if (IS_ERR(folio)) {
 			while (npages--) {
 				folio = page_folio(pages[npages]);