From a390ccb316beb8ea594b8695d53926710ca454a3 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Sun, 24 Oct 2021 16:26:07 +0300 Subject: fuse: add FOPEN_NOFLUSH Add flag returned by FUSE_OPEN and FUSE_CREATE requests to avoid flushing data cache on close. Different filesystems implement ->flush() is different ways: - Most disk filesystems do not implement ->flush() at all - Some network filesystem (e.g. nfs) flush local write cache of FMODE_WRITE file and send a "flush" command to server - Some network filesystem (e.g. cifs) flush local write cache of FMODE_WRITE file without sending an additional command to server FUSE flushes local write cache of ANY file, even non FMODE_WRITE and sends a "flush" command to server (if server implements it). The FUSE implementation of ->flush() seems over agressive and arbitrary and does not make a lot of sense when writeback caching is disabled. Instead of deciding on another arbitrary implementation that makes sense, leave the choice of per-file flush behavior in the hands of the server. Link: https://lore.kernel.org/linux-fsdevel/CAJfpegspE8e6aKd47uZtSYX8Y-1e1FWS0VL0DH2Skb9gQP5RJQ@mail.gmail.com/ Suggested-by: Miklos Szeredi Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi --- fs/fuse/file.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/fuse') diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 26730e699d68..b7f1a164e18a 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -476,6 +476,9 @@ static int fuse_flush(struct file *file, fl_owner_t id) if (fuse_is_bad(inode)) return -EIO; + if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache) + return 0; + err = write_inode_now(inode, 1); if (err) return err; -- cgit v1.2.3-58-ga151