Linus pointed out that checking only VMA_WRITE_BIT is incorrect. Private writable mappings (MAP_PRIVATE) set VM_WRITE but do not write back to the filesystem. Also, mappings that can become writable via mprotect() (VM_MAYWRITE) must be handled. Use vma_desc_test_all(VMA_SHARED_BIT, VMA_MAYWRITE_BIT) instead, which matches what other filesystems do. Suggested-by: Linus Torvalds Signed-off-by: Namjae Jeon --- fs/ntfs/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c index f55f55d4ca9a..e0265a8825f2 100644 --- a/fs/ntfs/file.c +++ b/fs/ntfs/file.c @@ -650,7 +650,7 @@ static int ntfs_file_mmap_prepare(struct vm_area_desc *desc) if (NInoCompressed(NTFS_I(inode))) return -EOPNOTSUPP; - if (vma_desc_test(desc, VMA_WRITE_BIT)) { + if (vma_desc_test_all(desc, VMA_SHARED_BIT, VMA_MAYWRITE_BIT)) { struct inode *inode = file_inode(file); loff_t from, to; int err; -- 2.25.1