fuse: create fuse_dev on /dev/fuse open instead of mount

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Allocate struct fuse_dev when opening the device.  This means that unlike
before, ->private_data is always set to a valid pointer.

The use of USE_DEV_SYNC_INIT magic pointer for the private_data is now
replaced with a simple bool sync_init member.

If sync INIT is not set, I/O on the device returns error before mount.
Keep this behavior by checking for the ->fc member.  If fud->fc is set, the
mount has succeeded.  Testing this used READ_ONCE(file->private_data) and
smp_mb() to try and provide the necessary semantics.  Switch this to
smp_store_release() and smp_load_acquire().

Setting fud->fc is protected by fuse_mutex, this is unchanged.

Will need this later so the /dev/fuse open file reference is not held
during FSCONFIG_CMD_CREATE.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

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This commit is contained in:

Miklos Szeredi 2026-03-11 21:02:41 +01:00

parent e45f591f70

commit a8dd5f1b73

5 changed files with 57 additions and 66 deletions

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47

fs/fuse/dev.c

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33

fs/fuse/fuse_dev_i.h

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6

fs/fuse/fuse_i.h

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35

fs/fuse/inode.c

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2

fs/fuse/virtio_fs.c

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