7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hongling Zeng [ Upstream commit 9cc5761b8f28f9cef72061094eb5e37e2cd44d97 ] ntfs_setattr_size() updates i_size and resizes the on-disk attribute without holding mapping->invalidate_lock. Page faults take the lock shared, so a fault racing the resize can resolve a VCN against the transient runlist state of ntfs_non_resident_attr_expand() and fail with a spurious SIGBUS, and can interleave with the size-change epilogue (truncate_pagecache(), i_size_write(), pagecache_isize_extended()). Take invalidate_lock exclusively around the whole resize after inode_dio_wait(), matching the fallocate path and other filesystems such as xfs, which wraps truncate in its mmaplock (= invalidate_lock). Fixes: 9c87959601e8 ("ntfs: update file operations") Cc: stable@vger.kernel.org Reviewed-by: Hyunchul Lee Reviewed-by: Baolin Liu Signed-off-by: Hongling Zeng Signed-off-by: Namjae Jeon Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/ntfs/file.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) --- a/fs/ntfs/file.c +++ b/fs/ntfs/file.c @@ -269,18 +269,25 @@ static int ntfs_setattr_size(struct inod return err; inode_dio_wait(vi); + + /* + * Serialize with page faults and pagecache instantiation so that + * readers cannot observe the size change until the attribute + * updates below have completed. + */ + filemap_invalidate_lock(vi->i_mapping); if (attr->ia_size > old_size) { truncate_pagecache(vi, old_size); i_size_write(vi, attr->ia_size); pagecache_isize_extended(vi, old_size, attr->ia_size); - } else + } else { truncate_setsize(vi, attr->ia_size); + } err = ntfs_truncate_vfs(vi, attr->ia_size, old_size); - if (err) { + if (err) i_size_write(vi, old_size); - return err; - } + filemap_invalidate_unlock(vi->i_mapping); return err; }