Andreas Dilger <adilger@xxxxxxxxx> wrote: > > Any thoughts on how that might scale? vfs_tmpfile() doesn't appear to > > require the directory inode lock. I presume the directory is required for > > security purposes in addition to being a way to specify the target > > filesystem. > > I don't see how that would help much? When it comes to dealing with a file I don't have cached, I can't probe the cache file to find out whether it has data that I can read until I've opened it (or found out it doesn't exist). When it comes to writing to a new cache file, I can't start writing until the file is created and opened - but this will potentially hold up close, data sync and writes that conflict (and have to implicitly sync). If I can use vfs_tmpfile() to defer synchronous directory accesses, that could be useful. As mentioned, creating a link to a temporary cache file (ie. modifying the directory) could be deferred to a background thread whilst allowing file I/O to progress to the tmpfile. David
