Re: How to Explicitly Sync When Appending to a File

I solved the invalid write, but I am still stuck on the syncing.

Apparently I needed to use the fs tied to the `handle` like so:

```cpp handle->fs().write(handle, bufrange, out); ```

So now I focused on the actual syncing, so I added the following:

```cpp handle->fs().queue_sync(handle);

auto res = handle->fs().complete_sync(handle); while (res == Vfs::File_io_service::SYNC_QUEUED) { root_dir.commit_and_wait(); } ```

With `root_dir` being the following:

```cpp Genode::Root_directory root_dir = rom.node().with_sub_node( "vfs", [&](const Genode::Node &config) -> Genode::Root_directory { return {env, heap, config}; }, [&]() -> Genode::Root_directory { Genode::error( "VFS was not configured properly: missing <vfs> under <config>"); return {env, heap, Genode::Node()}; }); ```

The first file gets written to disk, however, after that the program blocks again and no more writes are started. Am I handling the sync correctly?

Best, Rumen

________________________________________ From: Rumen Mitov via users users@lists.genode.org Sent: Tuesday, June 23, 2026 7:28 PM To: Ryan Davidovics via users Cc: Rumen Mitov Subject: How to Explicitly Sync When Appending to a File

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Hello,

I would like to sync the file-system after every invocation to `Genode::Append_file::append()`. However, the `_sync()` interface is private as are the Genode::Append_file's `_io` and `_handle`.

What is the recommended way to sync?

I tried using handles as well:

```cpp Vfs::File_system &fs{root_dir.root_dir()}; Vfs::Vfs_handle *handle {};

fs.open("foo", Vfs::Directory_service::Open_mode::OPEN_MODE_RDWR | Vfs::Directory_service::Open_mode::OPEN_MODE_CREATE, &handle, heap);

// file opens properly

for (long long unsigned i = 0; i < 10; i++) { auto _str = Genode::String<512>(Genode::Hex(i), "\n"); Genode::Const_byte_range_ptr const bufrange { _str.string(), _str.length() }; Genode::size_t out = 0;

auto res = fs.write(handle, bufrange, out); handle->advance_seek(out);

Genode::warning("WROTE: ", out, "B, RES: ", (Genode::uint32_t)res); }

fs.close(handle); ```

However, before I could add syncing to the above example, I noticed that `fs.write()` returns WRITE_ERR_INVALID. I am stuck on what could be wrong, as I based this example off of the internal implementation of `Genode::Writeable_file`.

As always, any help is greatly appreciated :)

Best, Rumen

P.S. This was tested on rump-ext2fs. _______________________________________________ users mailing list -- users@lists.genode.org To unsubscribe send an email to users-leave@lists.genode.org Archived at https://lists.genode.org/mailman3/hyperkitty/list/users@lists.genode.org/mes...