On Friday 17 January 2025 11:51:54 Steve French wrote: > On Fri, Jan 17, 2025 at 11:39 AM Darrick J. Wong <djwong@xxxxxxxxxx> wrote: > > > > On Fri, Jan 17, 2025 at 05:53:34PM +0100, Amir Goldstein wrote: > > > On Wed, Jan 15, 2025 at 12:59 AM Darrick J. Wong <djwong@xxxxxxxxxx> wrote: > <...> > > > Looking at the FILE_ATTRIBUTE_* flags defined in SMB protocol > > > (fs/smb/common/smb2pdu.h) I wonder how many of them will be > > > needed for applications beyond the obvious ones that were listed. > > > > Well they only asked for seven of them. ;) > > > > I chatted with Ted about this yesterday, and ... some of the attributes > > (like read only) imply that you'd want the linux server to enforce no > > writing to the file; some like archive seem a little superfluous since > > on linux you can compare cmtime from the backup against what's in the > > file now; and still others (like hidden/system) might just be some dorky > > thing that could be hidden in some xattr because a unix filesystem won't > > care. > > > > And then there are other attrs like "integrity stream" where someone > > with more experience with windows would have to tell me if fsverity > > provides sufficient behaviors or not. > > > > But maybe we should start by plumbing one of those bits in? I guess the > > gross part is that implies an ondisk inode format change or (gross) > > xattr lookups in the open path. > > > > We have talked about some of these missing flags in the past, but the > obvious ones that would be helpful i (e.g. is used in other operating > systems when view directories in the equivalent of the "Files" GUI is > checking FILE_ATTRIBUTE_OFFLINE to determine whether to query icons, > and additional metadata for files). In the past Unix used to have > various ways to determine this, but it is fairly common for files to > be tiered (where the data is in very slow storage offline - so should > only be opened and read by apps that really need to - not things like > GUIs browsing lists of files) so that attribute could be helpful. > > The other two obvious ones (missing in Linux but that some other OS > have filesystems which support) discussed before were > FILE_ATTRIBUTE_INTEGRITY_STREAM which could be set for files that need > stronger data integrity guarantees (if a filesystem allows files to be > marked for stronger data integrity guarantees) , and > FILE_ATTRIBUTE_NO_SCRUB_DATA that indicates integrity checks can be > skipped for this particular file. > -- > Thanks, > > Steve Thank you for information about integrity stream and these new things around. I have not included them into my initial list because I have not used them yet. That it why I listed only seven. But as I wrote in the other email, whatever API is chosen, it should be prepared for extending and integrity stream sounds like something could be included there.
