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This will make it possible to grab the fuse_dev and subsequently release the file that it came from. In the above case, fud->fc will be set to FUSE_DEV_FC_DISCONNECTED to indicate that this is no longer a functional device. When trying to assign an fc to such a disconnected fuse_dev, the fc is set to the disconnected state. Use atomic operations xchg() and cmpxchg() to prevent races. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
98 lines
2.7 KiB
C
98 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0
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*
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* FUSE: Filesystem in Userspace
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* Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
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*/
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#ifndef _FS_FUSE_DEV_I_H
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#define _FS_FUSE_DEV_I_H
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#include <linux/types.h>
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/* Ordinary requests have even IDs, while interrupts IDs are odd */
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#define FUSE_INT_REQ_BIT (1ULL << 0)
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#define FUSE_REQ_ID_STEP (1ULL << 1)
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extern struct wait_queue_head fuse_dev_waitq;
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struct fuse_arg;
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struct fuse_args;
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struct fuse_pqueue;
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struct fuse_req;
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struct fuse_iqueue;
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struct fuse_forget_link;
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struct fuse_copy_state {
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struct fuse_req *req;
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struct iov_iter *iter;
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struct pipe_buffer *pipebufs;
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struct pipe_buffer *currbuf;
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struct pipe_inode_info *pipe;
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unsigned long nr_segs;
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struct page *pg;
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unsigned int len;
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unsigned int offset;
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bool write:1;
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bool move_folios:1;
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bool is_uring:1;
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struct {
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unsigned int copied_sz; /* copied size into the user buffer */
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} ring;
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};
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/* fud->fc gets assigned to this value when /dev/fuse is closed */
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#define FUSE_DEV_FC_DISCONNECTED ((struct fuse_conn *) 1)
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/*
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* Lockless access is OK, because fud->fc is set once during mount and is valid
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* until the file is released.
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*
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* fud->fc is set to FUSE_DEV_FC_DISCONNECTED only after the containing file is
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* released, so result is safe to dereference in most cases. Exceptions are:
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* fuse_dev_put() and fuse_fill_super_common().
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*/
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static inline struct fuse_conn *fuse_dev_fc_get(struct fuse_dev *fud)
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{
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/* Pairs with xchg() in fuse_dev_install() */
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return smp_load_acquire(&fud->fc);
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}
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static inline struct fuse_dev *fuse_file_to_fud(struct file *file)
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{
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return file->private_data;
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}
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static inline struct fuse_dev *__fuse_get_dev(struct file *file)
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{
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struct fuse_dev *fud = fuse_file_to_fud(file);
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if (!fuse_dev_fc_get(fud))
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return NULL;
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return fud;
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}
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struct fuse_dev *fuse_get_dev(struct file *file);
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unsigned int fuse_req_hash(u64 unique);
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struct fuse_req *fuse_request_find(struct fuse_pqueue *fpq, u64 unique);
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void fuse_dev_end_requests(struct list_head *head);
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void fuse_copy_init(struct fuse_copy_state *cs, bool write,
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struct iov_iter *iter);
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void fuse_copy_finish(struct fuse_copy_state *cs);
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int fuse_copy_args(struct fuse_copy_state *cs, unsigned int numargs,
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unsigned int argpages, struct fuse_arg *args,
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int zeroing);
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int fuse_copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
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unsigned int nbytes);
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void fuse_dev_queue_forget(struct fuse_iqueue *fiq,
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struct fuse_forget_link *forget);
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void fuse_dev_queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req);
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bool fuse_remove_pending_req(struct fuse_req *req, spinlock_t *lock);
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bool fuse_request_expired(struct fuse_conn *fc, struct list_head *list);
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#endif
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