Messages in this thread | | | From | Miklos Szeredi <> | Date | Tue, 27 Sep 2022 11:46:44 +0200 | Subject | Re: [PATCH] fuse: In fuse_flush only wait if someone wants the return code |
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On Thu, 1 Sept 2022 at 16:07, Tycho Andersen <tycho@tycho.pizza> wrote: > > From: "Eric W. Biederman" <ebiederm@xmission.com> > > In my very light testing this resolves a hang where a thread of the > fuse server was accessing the fuse filesystem (the fuse server is > serving up), when the fuse server is killed. > > The practical problem is that the fuse server file descriptor was > being closed after the file descriptor into the fuse filesystem so > that the fuse filesystem operations were being blocked for instead of > being aborted. Simply skipping the unnecessary wait resolves this > issue. > > This is just a proof of concept and someone should look to see if the > fuse max_background limit could cause a problem with this approach.
Maybe you missed my comments here:
https://lore.kernel.org/all/CAJfpegsTmiO-sKaBLgoVT4WxDXBkRES=HF1YmQN1ES7gfJEJ+w@mail.gmail.com/
I'm generally okay with this, but please write a proper changelog for the patch, also mentioning the issues related to posix locks.
> --- a/fs/fuse/file.c > +++ b/fs/fuse/file.c > @@ -464,6 +464,67 @@ static void fuse_sync_writes(struct inode *inode) > fuse_release_nowrite(inode); > } > > +struct fuse_flush_args { > + struct fuse_args args; > + struct fuse_flush_in inarg; > + struct inode *inode; > + struct fuse_file *ff; > +}; > + > +static void fuse_flush_end(struct fuse_mount *fm, struct fuse_args *args, int err) > +{ > + struct fuse_flush_args *fa = container_of(args, typeof(*fa), args); > + > + if (err == -ENOSYS) { > + fm->fc->no_flush = 1; > + err = 0; > + } > + > + /* > + * In memory i_blocks is not maintained by fuse, if writeback cache is > + * enabled, i_blocks from cached attr may not be accurate. > + */ > + if (!err && fm->fc->writeback_cache) > + fuse_invalidate_attr_mask(fa->inode, STATX_BLOCKS); > + > + > + iput(fa->inode); > + fuse_file_put(fa->ff, false, false); > + kfree(fa); > +} > + > +static int fuse_flush_async(struct file *file, fl_owner_t id) > +{ > + struct inode *inode = file_inode(file); > + struct fuse_mount *fm = get_fuse_mount(inode); > + struct fuse_file *ff = file->private_data; > + struct fuse_flush_args *fa; > + int err; > + > + fa = kzalloc(sizeof(*fa), GFP_KERNEL); > + if (!fa) > + return -ENOMEM; > + > + fa->inarg.fh = ff->fh; > + fa->inarg.lock_owner = fuse_lock_owner_id(fm->fc, id); > + fa->args.opcode = FUSE_FLUSH; > + fa->args.nodeid = get_node_id(inode); > + fa->args.in_numargs = 1; > + fa->args.in_args[0].size = sizeof(fa->inarg); > + fa->args.in_args[0].value = &fa->inarg; > + fa->args.force = true; > + fa->args.nocreds = true; > + fa->args.end = fuse_flush_end; > + fa->inode = igrab(inode);
Grabbing the inode should already taken care of by fuse_file_release().
Also please try to reduce duplication in both the above functions.
Thanks, Miklos
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