mirror of
https://github.com/libfuse/libfuse.git
synced 2026-07-07 14:47:41 +08:00
Bernd Schubert
87 lines
2.4 KiB
SYSTEMD
87 lines
2.4 KiB
SYSTEMD
FUSE Mount API Flowcharts
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=========================
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Old Mount API
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-------------
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fuse_kern_mount()
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+-- fuse_mount_sys()
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| +-- Try direct mount → mount() syscall
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| +-- On EPERM: fuse_mount_fusermount()
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| +-- socketpair()
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| +-- spawn fusermount3 (no --sync-init)
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| +-- fusermount3: open /dev/fuse, mount(), send fd
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| +-- receive_fd() → return fd
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+-- Worker threads started AFTER mount
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└─> FUSE_INIT asynchronous (queued in kernel)
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New Mount API - Privileged Mount
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---------------------------------
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fuse_session_mount_new_api()
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+-- fuse_kern_mount_prepare() → open /dev/fuse → fd
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+-- session_start_sync_init(se, fd)
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| +-- ioctl(fd, FUSE_DEV_IOC_SYNC_INIT)
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| +-- pthread_create(worker) → ready to process FUSE_INIT
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+-- fuse_kern_fsmount_mo()
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| +-- fsopen/fsconfig/fsmount (BLOCKS until FUSE_INIT completes)
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| +-- Worker processes FUSE_INIT during fsmount()
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| +-- move_mount()
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+-- session_wait_sync_init_completion(se) → pthread_join
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└─> return fd
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New Mount API - EPERM Fallback (fusermount3 with sync-init)
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------------------------------------------------------------
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fuse_session_mount_new_api()
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+-- fuse_kern_mount_prepare() → open /dev/fuse → fd1
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+-- session_start_sync_init(se, fd1)
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| +-- ioctl(fd1, FUSE_DEV_IOC_SYNC_INIT)
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| +-- pthread_create(worker) → ready with fd1
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+-- fuse_kern_fsmount_mo() → EPERM
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+-- *** FALLBACK TO FUSERMOUNT3 WITH SYNC-INIT ***
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+-- session_wait_sync_init_completion(se)
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| +-- pthread_cancel/join → terminate worker with wrong fd1
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+-- close(fd1)
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+-- fuse_mount_fusermount_sync_init() [NEW]
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| +-- socketpair()
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| +-- spawn fusermount3 --sync-init
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| +-- fusermount3: open /dev/fuse → fd2, send fd2
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| +-- receive_fd() → fd2
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| +-- fusermount3 waits for signal
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| └─> return fd2, sock
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+-- session_start_sync_init(se, fd2)
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| +-- ioctl(fd2, FUSE_DEV_IOC_SYNC_INIT)
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| +-- pthread_create(worker) → ready with fd2
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+-- send_proceed_signal(sock) [NEW]
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| +-- send(sock, "\0", 1) → signal fusermount3
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+-- fusermount3: mount() (BLOCKS)
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| +-- Kernel sends FUSE_INIT to fd2
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| +-- Worker processes FUSE_INIT
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| +-- mount() returns
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+-- close(sock)
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+-- session_wait_sync_init_completion(se) → pthread_join
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└─> return fd2
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