feat(linux/vfs): integrate openvfs linux virtual files plugin by mgallien · Pull Request #10635 · nextcloud/desktop

mgallien · 2026-08-20T15:41:54Z

Resolves

#

Summary

TODO

...

Checklist

Sign-off message is added to all commits.
The commit history is clean with no merge commits.
- How to rebase your commits
- How to squash commits with rebase
Uploaded screenshots from before and after for UI changes.
Test(s) added to branch, with before/after results included in PR description, for performance improvements where applicable.
Documentation has been updated or is not required.
Backports requested where applicable (critical bugfixes).
Labels added where applicable (bug/enhancement).
Milestone added for target version.

AI (if applicable)

The content of this PR was partly or fully generated using AI
- I have read the guidelines for AI-assisted contributions.
- I have read Nextcloud's AI Contribution Policy.

mgallien · 2026-08-26T14:08:43Z

currently able to complete the initial synchronization
missing is proper communication between the openvfs fuse daemon and the desktop files client
will need investigation

mgallien · 2026-08-27T14:05:00Z

Current UI on linux to decide what type of synchronization the user wants to enable

@kra-mo We would want to offer an easy way to test the linux virtual files plug-in while recommending people to not use for production use (until it is ready for that)
any idea how to tune the UI to achieve that ?
I understand that this may not be easy to do 😄
I would still like to have an easy way of discovering the new feature (currently I modified the code as if the plug-in should be the default as seen in the screenshot)
previous experimental plug-in needed to modify the configuration file manually

kra-mo · 2026-08-27T14:12:22Z

@mgallien I think being straightforward with the text is probably the best idea. For example:

Virtual files (beta)
Download files on-demand. This feature is in an early preview. Recommended only with proper backups.

And don't have it be the default selection.

mgallien · 2026-08-28T09:57:00Z

I need to implement the suggestion for the selection of the synchronization types
I have now working hydration
so this is ready for testing
the disclaimer is that there is no guarantee, so feedback is very much welcome but be careful with your data

mgallien · 2026-08-28T09:58:08Z

there is a build and runtime dependency on https://github.com/opencloud-eu/openvfs

github-actions

⚠️ Clang-Tidy found issue(s) with the introduced code (57/63)

github-actions · 2026-09-09T19:08:45Z

     */
    bool multipleAccountsRegistered = false;
+
+    const FileSystem::Path &root() const;


⚠️ modernize-use-nodiscard ⚠️
function root should be marked [[nodiscard]]

Suggested change

const FileSystem::Path &root() const;

[[nodiscard]] const FileSystem::Path &root() const;

github-actions · 2026-09-09T19:08:45Z

    };
    FolderQuota _folderQuota;
+
+    QString localName() const


⚠️ modernize-use-nodiscard ⚠️
function localName should be marked [[nodiscard]]

Suggested change

QString localName() const

[[nodiscard]] QString localName() const

github-actions · 2026-09-09T19:08:45Z

+         */
+        static Path relative(QAnyStringView path);
+
+        const std::filesystem::path &get() const { return _path; }


⚠️ modernize-use-nodiscard ⚠️
function get should be marked [[nodiscard]]

Suggested change

const std::filesystem::path &get() const { return _path; }

[[nodiscard]] const std::filesystem::path &get() const { return _path; }

github-actions · 2026-09-09T19:08:45Z

     */
    bool multipleAccountsRegistered = false;
+
+    const FileSystem::Path &root() const;


⚠️ modernize-use-nodiscard ⚠️
function root should be marked [[nodiscard]]

Suggested change

const FileSystem::Path &root() const;

[[nodiscard]] const FileSystem::Path &root() const;

github-actions · 2026-09-09T19:08:45Z

    };
    FolderQuota _folderQuota;
+
+    QString localName() const


⚠️ modernize-use-nodiscard ⚠️
function localName should be marked [[nodiscard]]

Suggested change

QString localName() const

[[nodiscard]] QString localName() const

github-actions · 2026-09-09T19:08:45Z

+         */
+        static Path relative(QAnyStringView path);
+
+        const std::filesystem::path &get() const { return _path; }


⚠️ modernize-use-nodiscard ⚠️
function get should be marked [[nodiscard]]

Suggested change

const std::filesystem::path &get() const { return _path; }

[[nodiscard]] const std::filesystem::path &get() const { return _path; }

github-actions · 2026-09-09T19:08:45Z

     */
    bool multipleAccountsRegistered = false;
+
+    const FileSystem::Path &root() const;


⚠️ modernize-use-nodiscard ⚠️
function root should be marked [[nodiscard]]

Suggested change

const FileSystem::Path &root() const;

[[nodiscard]] const FileSystem::Path &root() const;

github-actions · 2026-09-09T19:08:45Z

    };
    FolderQuota _folderQuota;
+
+    QString localName() const


⚠️ modernize-use-nodiscard ⚠️
function localName should be marked [[nodiscard]]

Suggested change

QString localName() const

[[nodiscard]] QString localName() const

github-actions · 2026-09-09T19:08:45Z

+         */
+        static Path relative(QAnyStringView path);
+
+        const std::filesystem::path &get() const { return _path; }


⚠️ modernize-use-nodiscard ⚠️
function get should be marked [[nodiscard]]

Suggested change

const std::filesystem::path &get() const { return _path; }

[[nodiscard]] const std::filesystem::path &get() const { return _path; }

github-actions · 2026-09-09T19:08:45Z

     */
    bool multipleAccountsRegistered = false;
+
+    const FileSystem::Path &root() const;


⚠️ modernize-use-nodiscard ⚠️
function root should be marked [[nodiscard]]

Suggested change

const FileSystem::Path &root() const;

[[nodiscard]] const FileSystem::Path &root() const;

github-actions

⚠️ Clang-Tidy found issue(s) with the introduced code (58/63)

github-actions

⚠️ Clang-Tidy found issue(s) with the introduced code (59/63)

github-actions

⚠️ Clang-Tidy found issue(s) with the introduced code (60/63)

github-actions

⚠️ Clang-Tidy found issue(s) with the introduced code (61/63)

github-actions

⚠️ Clang-Tidy found issue(s) with the introduced code (62/63)

github-actions

⚠️ Clang-Tidy found issue(s) with the introduced code (63/63)

not sure why it does that

github-actions · 2026-09-09T21:04:25Z

Artifact containing the Flatpak bundle: com.nextcloud.desktopclient.nextcloud.flatpak.zip

Digest: sha256:22411da8d96a8230790ef49a866e986ddc31bfc70789d4769f0d9ace618ee5a1

To test this change/fix you can download the above artifact file, unzip it, and install the bundle with:
flatpak install --user com.nextcloud.desktopclient.nextcloud.flatpak

Please make sure to quit your existing Nextcloud app and backup your data.

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

we need to store and restore the account UUID that is used to identify the synchronization folder that will enable connection again to the folder when restarting the client Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

we want to offer an easy way to test the linux on-demand (virtula files) feature we want to still select the classical sync by default and warn users of virtual files to be cautious with it Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com> Assisted-by: ClaudeCode:claude-sonnet-5

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

should enable to build flatpak packages directly from desktop repository modify the build manifest to enable the new openvfs virtual files feature Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

github-actions · 2026-09-14T07:54:36Z

Artifact containing the AppImage: nextcloud-appimage-pr-10635.zip

Digest: sha256:836105d05c3356c2c536a7de96d234521223768db1f01c8509f8049dcc4eabd4

To test this change/fix you can download the above artifact file, unzip it, and run it.

Please make sure to quit your existing Nextcloud app and backup your data.

nilsding · 2026-09-14T08:10:53Z

+// LocalInfo OpenVFS::statTypeVirtualFile(const std::filesystem::directory_entry &path, ItemType type)
+// {
+//     if (type == ItemTypeFile) {
+//         const auto attribs = placeHolderAttributes(path.path());
+//         if (attribs.state == ::OpenVFS::Constants::States::DeHydrated) {
+//             type = ItemTypeVirtualFile;
+//             if (attribs.pinState == convertPinState(PinState::AlwaysLocal)) {
+//                 type = ItemTypeVirtualFileDownload;
+//             }
+//         } else {
+//             if (attribs.pinState == convertPinState(PinState::OnlineOnly)) {
+//                 type = ItemTypeVirtualFileDehydration;
+//             }
+//         }
+//     }
+//     qCDebug(lcOpenVFS) << path.path().native() << Utility::enumToString(type);
+//     return LocalInfo(path, type);
+// }
+


Suggested change

// LocalInfo OpenVFS::statTypeVirtualFile(const std::filesystem::directory_entry &path, ItemType type)

// {

// if (type == ItemTypeFile) {

// const auto attribs = placeHolderAttributes(path.path());

// if (attribs.state == ::OpenVFS::Constants::States::DeHydrated) {

// type = ItemTypeVirtualFile;

// if (attribs.pinState == convertPinState(PinState::AlwaysLocal)) {

// type = ItemTypeVirtualFileDownload;

// }

// } else {

// if (attribs.pinState == convertPinState(PinState::OnlineOnly)) {

// type = ItemTypeVirtualFileDehydration;

// }

// }

// }

// qCDebug(lcOpenVFS) << path.path().native() << Utility::enumToString(type);

// return LocalInfo(path, type);

// }

nilsding · 2026-09-14T08:14:41Z

+    if (stat->type == ItemTypeDirectory) {
+        return false;
+    }


should this catch virtual directories early as well?

Suggested change

if (stat->type == ItemTypeDirectory) {

return false;

}

if (stat->type == ItemTypeDirectory || stat->type == ItemTypeVirtualDirectory) {

return false;

}

that would be covered by the if (stat->type == ItemTypeFile) below

nilsding · 2026-09-14T08:16:40Z

+    const auto owner = xattrOwnerString(params.account->uuid()).toStdString();
+    if (const auto info = ::OpenVFS::Registration::registerFilesystem(std::filesystem::path{params.filesystemPath.toStdWString()}, owner); !info) {
+        if (info.owner() != owner) {
+            Q_EMIT error(tr("Unable to claim the sync root for files on demand, the folder is already claimed by %1").arg(info.owner()));


Suggested change

Q_EMIT error(tr("Unable to claim the sync root for files on demand, the folder is already claimed by %1").arg(info.owner()));

//: %1: system user name who is the owner of the sync root directory

Q_EMIT error(tr("Unable to claim the sync root for files on demand, the folder is already claimed by %1").arg(info.owner()));

nilsding · 2026-09-14T08:18:04Z

+    // if (OCC::Utility::runningInAppImage()) {
+    //     auto appimagePath = OCC::FileSystem::Path(qApp->applicationDirPath()) / "../etc/xdg/openvfs/config.json";
+    //     if (appimagePath.exists()) {
+    //         return appimagePath;
+    //     }
+    // }


is this not necessary?

I will double check

nilsding · 2026-09-14T08:23:24Z

+      PUBLIC
+      OpenVFS::LibOpenVFS
+  )
+endif()


does libsync really need to link to OpenVFS? The appimage build script now includes the --library=/root/linux-gcc-x86_64/lib64/libopenvfs.so option, maybe this change here can be omitted

no
without that, the plugin loader is not finding the libopenvfs.so needed dependency
do not ask me why the loader behave that way inside the AppImage, I did not understand it

sonarqubecloud · 2026-09-14T08:41:35Z

Quality Gate failed

Failed conditions
9.6% Coverage on New Code (required ≥ 80%)
53 New Code Smells (required ≤ 0)

See analysis details on SonarQube Cloud

Catch issues before they fail your Quality Gate with our IDE extension SonarQube for IDE

mgallien mentioned this pull request Aug 21, 2026

[Bug][Linux][VFS] Valid filename fails to sync because .nextcloud suffix exceeds filesystem NAME_MAX #10636

Closed

8 tasks

Rello moved this to NC35 in 💻 Desktop Clients team Aug 21, 2026

Rello added this to 💻 Desktop Clients team Aug 21, 2026

mgallien force-pushed the feature/integrateOpenVfsPlugin branch 2 times, most recently from f1a363a to 702ac22 Compare August 26, 2026 13:12

mgallien force-pushed the feature/integrateOpenVfsPlugin branch from 5cc28ff to aab773f Compare August 27, 2026 08:35

mgallien marked this pull request as ready for review August 28, 2026 09:54

mgallien requested review from camilasan, claucambra, i2h3 and nilsding as code owners August 28, 2026 09:54

mgallien force-pushed the feature/integrateOpenVfsPlugin branch from bbb62b9 to af01969 Compare August 28, 2026 09:55

mgallien force-pushed the feature/integrateOpenVfsPlugin branch from af01969 to 72b1e73 Compare August 28, 2026 10:03

Rello mentioned this pull request Aug 31, 2026

VFS OnlineOnly pin state doesn't dehydrate on Linux — 34.0.2 / 3.16.7 #10691

Closed

8 tasks

This was referenced Aug 31, 2026

Create and write files whose mode carries no owner-write bit opencloud-eu/openvfs#65

Open

Truncate through the descriptor when there is one opencloud-eu/openvfs#66

Open

mgallien force-pushed the feature/integrateOpenVfsPlugin branch 2 times, most recently from 17a3181 to f67dc46 Compare September 1, 2026 12:37

Rello mentioned this pull request Sep 1, 2026

VFS pin state (OnlineOnly) silently lost when the sync journal is rebuilt — client re-hydrates entire trees with no warning (Linux suffix VFS, 4.0.6) #10705

Closed

mgallien force-pushed the feature/integrateOpenVfsPlugin branch 6 times, most recently from c116229 to 62e5899 Compare September 9, 2026 07:45

github-actions Bot requested changes Sep 9, 2026

View reviewed changes

github-actions Bot previously requested changes Sep 9, 2026

View reviewed changes

Comment thread src/libsync/syncfileitem.h Outdated

Comment thread src/common/path.h Outdated

Comment thread src/common/vfs.h Outdated

Comment thread src/libsync/syncfileitem.h Outdated

mgallien force-pushed the feature/integrateOpenVfsPlugin branch from bda0c3a to c180e70 Compare September 9, 2026 20:39

Rello added the os: 🐧 Linux label Sep 10, 2026

mgallien added this to the 35.0.0 milestone Sep 14, 2026

mgallien added feature: 💽 virtual filesystem 3. to review labels Sep 14, 2026

mgallien and others added 12 commits September 14, 2026 09:37

feat(linux/vfs): integrate openvfs linux virtual files plugin

088aae3

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

fix(openvfs): fix loading of the plug-in and make it default on linux

d4dceb7

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

fix(linux/vfs): fix socket API communication with fuse driver

59d2d00

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

fix(linux/vfs): Add socket api call for hydration

ebc6e4c

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

fix(linux/vfs): fix lookup of socket commands needed for hydration

4b8d11f

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

fix(linux/vfs): makes sure the hydration job can do something useful

5e51e1e

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

fix(linux/vfs): fix dehydration of files

04eb32d

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

feat(linux/vfs): add flatpak manifest and enable virtual files

66f2244

should enable to build flatpak packages directly from desktop repository modify the build manifest to enable the new openvfs virtual files feature Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

feat(linux/vfs): build AppImage with openvfs virtual files enabled

4dd98b1

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

fix: make the code follow our clang-tidy rules

60e2513

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

mgallien force-pushed the feature/integrateOpenVfsPlugin branch from c180e70 to 60e2513 Compare September 14, 2026 07:38

nilsding requested changes Sep 14, 2026

View reviewed changes

	const FileSystem::Path &root() const;
	[[nodiscard]] const FileSystem::Path &root() const;

	QString localName() const
	[[nodiscard]] QString localName() const

	const std::filesystem::path &get() const { return _path; }
	[[nodiscard]] const std::filesystem::path &get() const { return _path; }

	Q_EMIT error(tr("Unable to claim the sync root for files on demand, the folder is already claimed by %1").arg(info.owner()));
	//: %1: system user name who is the owner of the sync root directory
	Q_EMIT error(tr("Unable to claim the sync root for files on demand, the folder is already claimed by %1").arg(info.owner()));

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Conversation

mgallien commented Aug 20, 2026

Resolves

Summary

TODO

Checklist

AI (if applicable)

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mgallien commented Aug 26, 2026

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mgallien commented Aug 27, 2026

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kra-mo commented Aug 27, 2026

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mgallien commented Aug 28, 2026

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