fcntl(F_SETFL) and fadvise performs direct manipulation with file's internals. w/o notifying to fs layer. This behavior be not be suitable for some filesystems (mostly stack-fs like ecryptfs, unionfs, etc). Let's introduce new ->set_flags() callback for that purpose. This callback is responsible for flags check so ->check_flags() no longer required. TOC: fs: fcntl add set_flags wrapper -v2 fs: add fadvise file_operation ecryptfs: add fadvise/set_flags calbacks cifs: add set_flag callback *OPEN ISSUE REMAINS* This series does not fix all issues related with set_flags. Race between fcntl(toggling O_DIRECT) vs write() is still possible Usually O_DIRECT checked twice during call chain: ->xxx_file_write_iter --->__generic_file_write_iter So we may end-up up with two different values. Some filesystems (btrfs/xfs) avoid this issue by copy-pasting __generic_file_write_iter. One of possible way to fix this issue it to save flags in kiocb->ki_flags as we already do with ->ki_pos. And fixup all places accordingly. I've calculated numbers of direct access to ->f_flags it is close to 150, half of that number is ->open() methods. So patch would not be gigantic. And finally here is my question to AlViro and Christoph and other VFS-people: *Are you agree with that approach?* Please say your word. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
