kernel/linux.git/fs/fuse/inode.c, branch v6.12.80

fuse: zero initialize inode private data

2025-11-13T20:34:15+00:00

[ Upstream commit 3ca1b311181072415b6432a169de765ac2034e5a ] This is slightly tricky, since the VFS uses non-zeroing allocation to preserve some fields that are left in a consistent state. Reported-by: Chunsheng Luo Closes: https://lore.kernel.org/all/20250818083224.229-1-luochunsheng@ustc.edu/ Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

fs/fuse: introduce and use fuse_simple_idmap_request() helper

2024-09-23T09:07:55+00:00

Let's convert all existing callers properly. No functional changes intended. Suggested-by: Christian Brauner Signed-off-by: Alexander Mikhalitsyn Reviewed-by: Christian Brauner Signed-off-by: Miklos Szeredi

fuse: allow idmapped mounts

2024-09-04T14:51:11+00:00

Now we have everything in place and we can allow idmapped mounts by setting the FS_ALLOW_IDMAP flag. Notice that real availability of idmapped mounts will depend on the fuse daemon. Fuse daemon have to set FUSE_ALLOW_IDMAP flag in the FUSE_INIT reply. To discuss: - we enable idmapped mounts support only if "default_permissions" mode is enabled, because otherwise we would need to deal with UID/GID mappings in the userspace side OR provide the userspace with idmapped req->in.h.uid/req->in.h.gid values which is not something that we probably want to. Idmapped mounts philosophy is not about faking caller uid/gid. Some extra links and examples: - libfuse support https://github.com/mihalicyn/libfuse/commits/idmap_support - fuse-overlayfs support: https://github.com/mihalicyn/fuse-overlayfs/commits/idmap_support - cephfs-fuse conversion example https://github.com/mihalicyn/ceph/commits/fuse_idmap - glusterfs conversion example https://github.com/mihalicyn/glusterfs/commits/fuse_idmap Signed-off-by: Alexander Mikhalitsyn Reviewed-by: Christian Brauner Signed-off-by: Miklos Szeredi

fuse: add an idmap argument to fuse_simple_request

2024-09-04T14:48:22+00:00

If idmap == NULL *and* filesystem daemon declared idmapped mounts support, then uid/gid values in a fuse header will be -1. No functional changes intended. Signed-off-by: Alexander Mikhalitsyn Signed-off-by: Miklos Szeredi

fuse: add basic infrastructure to support idmappings

2024-09-04T14:48:22+00:00

Add some preparational changes in fuse_get_req/fuse_force_creds to handle idmappings. Miklos suggested [1], [2] to change the meaning of in.h.uid/in.h.gid fields when daemon declares support for idmapped mounts. In a new semantic, we fill uid/gid values in fuse header with a id-mapped caller uid/gid (for requests which create new inodes), for all the rest cases we just send -1 to userspace. No functional changes intended. Link: https://lore.kernel.org/all/CAJfpegsVY97_5mHSc06mSw79FehFWtoXT=hhTUK_E-Yhr7OAuQ@mail.gmail.com/ [1] Link: https://lore.kernel.org/all/CAJfpegtHQsEUuFq1k4ZbTD3E1h-GsrN3PWyv7X8cg6sfU_W2Yw@mail.gmail.com/ [2] Signed-off-by: Alexander Mikhalitsyn Signed-off-by: Miklos Szeredi

fuse: disable the combination of passthrough and writeback cache

2024-08-29T09:43:01+00:00

Current design and handling of passthrough is without fuse caching and with that FUSE_WRITEBACK_CACHE is conflicting. Fixes: 7dc4e97a4f9a ("fuse: introduce FUSE_PASSTHROUGH capability") Cc: stable@kernel.org # v6.9 Signed-off-by: Bernd Schubert Acked-by: Amir Goldstein Reviewed-by: Josef Bacik Signed-off-by: Miklos Szeredi

fuse: Convert to new uid/gid option parsing helpers

2024-07-03T14:55:11+00:00

Convert to new uid/gid option parsing helpers Signed-off-by: Eric Sandeen Link: https://lore.kernel.org/r/4e1a4efa-4ca5-4358-acee-40efd07c3c44@redhat.com Reviewed-by: Christian Brauner Reviewed-by: Josef Bacik Signed-off-by: Christian Brauner

fuse: verify {g,u}id mount options correctly

2024-07-03T14:55:11+00:00

As was done in 0200679fc795 ("tmpfs: verify {g,u}id mount options correctly") we need to validate that the requested uid and/or gid is representable in the filesystem's idmapping. Cribbing from the above commit log, The contract for {g,u}id mount options and {g,u}id values in general set from userspace has always been that they are translated according to the caller's idmapping. In so far, fuse has been doing the correct thing. But since fuse is mountable in unprivileged contexts it is also necessary to verify that the resulting {k,g}uid is representable in the namespace of the superblock. Fixes: c30da2e981a7 ("fuse: convert to use the new mount API") Cc: stable@vger.kernel.org # 5.4+ Signed-off-by: Eric Sandeen Link: https://lore.kernel.org/r/8f07d45d-c806-484d-a2e3-7a2199df1cd2@redhat.com Reviewed-by: Christian Brauner Reviewed-by: Josef Bacik Signed-off-by: Christian Brauner

fuse: fix wrong ff->iomode state changes from parallel dio write

2024-04-15T08:12:03+00:00

There is a confusion with fuse_file_uncached_io_{start,end} interface. These helpers do two things when called from passthrough open()/release(): 1. Take/drop negative refcount of fi->iocachectr (inode uncached io mode) 2. State change ff->iomode IOM_NONE <-> IOM_UNCACHED (file uncached open) The calls from parallel dio write path need to take a reference on fi->iocachectr, but they should not be changing ff->iomode state, because in this case, the fi->iocachectr reference does not stick around until file release(). Factor out helpers fuse_inode_uncached_io_{start,end}, to be used from parallel dio write path and rename fuse_file_*cached_io_{start,end} helpers to fuse_file_*cached_io_{open,release} to clarify the difference. Fixes: 205c1d802683 ("fuse: allow parallel dio writes with FUSE_DIRECT_IO_ALLOW_MMAP") Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

Merge tag 'fuse-update-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

2024-03-15T16:47:14+00:00

Pull fuse updates from Miklos Szeredi: - Add passthrough mode for regular file I/O. This allows performing read and write (also via memory maps) on a backing file without incurring the overhead of roundtrips to userspace. For now this is only allowed to privileged servers, but this limitation will go away in the future (Amir Goldstein) - Fix interaction of direct I/O mode with memory maps (Bernd Schubert) - Export filesystem tags through sysfs for virtiofs (Stefan Hajnoczi) - Allow resending queued requests for server crash recovery (Zhao Chen) - Misc fixes and cleanups * tag 'fuse-update-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (38 commits) fuse: get rid of ff->readdir.lock fuse: remove unneeded lock which protecting update of congestion_threshold fuse: Fix missing FOLL_PIN for direct-io fuse: remove an unnecessary if statement fuse: Track process write operations in both direct and writethrough modes fuse: Use the high bit of request ID for indicating resend requests fuse: Introduce a new notification type for resend pending requests fuse: add support for explicit export disabling fuse: __kuid_val/__kgid_val helpers in fuse_fill_attr_from_inode() fuse: fix typo for fuse_permission comment fuse: Convert fuse_writepage_locked to take a folio fuse: Remove fuse_writepage virtio_fs: remove duplicate check if queue is broken fuse: use FUSE_ROOT_ID in fuse_get_root_inode() fuse: don't unhash root fuse: fix root lookup with nonzero generation fuse: replace remaining make_bad_inode() with fuse_make_bad() virtiofs: drop __exit from virtio_fs_sysfs_exit() fuse: implement passthrough for mmap fuse: implement splice read/write passthrough ...