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On Mar 28 18:35, Ben RUBSON wrote: > On 28 Mar 2018, Ben RUBSON wrote: > > > Hi, > > > > I'm porting a FUSE FS to Cygwin, and I focus especially on readdir() > > performance. > > > > What I see is that when readdir() occurs, each file of the directory is > > as expected (at least I think) stated (getattr), but also opened (open). > > The first block of the file was even red, until I set the notexec mount > > option. > > > > My question is, why is every file opened ? > > This is quite a performance killer, particularly for a FUSE FS. > > > > I thought this was to calculate the inode number, I then set the ihash > > mount option, but it did not help. > > I may be totally wrong, but perhaps the culprit is the following code path ? > https://github.com/mirror/newlib-cygwin/blob/master/winsup/cygwin/fhandler_disk_file.cc#L2262 > Perhaps we simply don't need to open the file if (!hasgood_inode ()) ? > > That would be a nice performance improvement ! You should make sure that the hasgood_inode() check works for your FUSE FS. Check at the end of fs_info::update(): has_acls (flags () & FS_PERSISTENT_ACLS); /* Netapp inode numbers are fly-by-night. */ hasgood_inode ((has_acls () && !is_netapp ()) || is_nfs ()); So your filesystem should return the FS_PERSISTENT_ACLS flags in a call to NtQueryVolumeInformationFile(..., FileFsAttributeInformation) Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat
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