/* FUSE: Filesystem in Userspace Copyright (C) 2001-2006 Miklos Szeredi This program can be distributed under the terms of the GNU GPL. See the file COPYING. */ #include #include #include #include #include #include #include #include #include /** Max number of pages that can be used in a single read request */ #define FUSE_MAX_PAGES_PER_REQ 32 /** Maximum number of outstanding background requests */ #define FUSE_MAX_BACKGROUND 12 /** Congestion starts at 75% of maximum */ #define FUSE_CONGESTION_THRESHOLD (FUSE_MAX_BACKGROUND * 75 / 100) /** It could be as large as PATH_MAX, but would that have any uses? */ #define FUSE_NAME_MAX 1024 /** Number of dentries for each connection in the control filesystem */ #define FUSE_CTL_NUM_DENTRIES 3 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem module will check permissions based on the file mode. Otherwise no permission checking is done in the kernel */ #define FUSE_DEFAULT_PERMISSIONS (1 << 0) /** If the FUSE_ALLOW_OTHER flag is given, then not only the user doing the mount will be allowed to access the filesystem */ #define FUSE_ALLOW_OTHER (1 << 1) /** List of active connections */ extern struct list_head fuse_conn_list; /** Global mutex protecting fuse_conn_list and the control filesystem */ extern struct mutex fuse_mutex; /** FUSE inode */ struct fuse_inode { /** Inode data */ struct inode inode; /** Unique ID, which identifies the inode between userspace * and kernel */ u64 nodeid; /** Number of lookups on this inode */ u64 nlookup; /** The request used for sending the FORGET message */ struct fuse_req *forget_req; /** Time in jiffies until the file attributes are valid */ u64 i_time; /** The sticky bit in inode->i_mode may have been removed, so preserve the original mode */ mode_t orig_i_mode; /** Version of last attribute change */ u64 attr_version; }; /** FUSE specific file data */ struct fuse_file { /** Request reserved for flush and release */ struct fuse_req *reserved_req; /** File handle used by userspace */ u64 fh; /** Refcount */ atomic_t count; }; /** One input argument of a request */ struct fuse_in_arg { unsigned size; const void *value; }; /** The request input */ struct fuse_in { /** The request header */ struct fuse_in_header h; /** True if the data for the last argument is in req->pages */ unsigned argpages:1; /** Number of arguments */ unsigned numargs; /** Array of arguments */ struct fuse_in_arg args[3]; }; /** One output argument of a request */ struct fuse_arg { unsigned size; void *value; }; /** The request output */ struct fuse_out { /** Header returned from userspace */ struct fuse_out_header h; /* * The following bitfields are not changed during the request * processing */ /** Last argument is variable length (can be shorter than arg->size) */ unsigned argvar:1; /** Last argument is a list of pages to copy data to */ unsigned argpages:1; /** Zero partially or not copied pages */ unsigned page_zeroing:1; /** Number or arguments */ unsigned numargs; /** Array of arguments */ struct fuse_arg args[3]; }; /** The request state */ enum fuse_req_state { FUSE_REQ_INIT = 0, FUSE_REQ_PENDING, FUSE_REQ_READING, FUSE_REQ_SENT, FUSE_REQ_WRITING, FUSE_REQ_FINISHED }; struct fuse_conn; /** * A request to the client */ struct fuse_req { /** This can be on either pending processing or io lists in fuse_conn */ struct list_head list; /** Entry on the interrupts list */ struct list_head intr_entry; /** refcount */ atomic_t count; /** Unique ID for the interrupt request */ u64 intr_unique; /* * The following bitfields are either set once before the * request is queued or setting/clearing them is protected by * fuse_conn->lock */ /** True if the request has reply */ unsigned isreply:1; /** Force sending of the request even if interrupted */ unsigned force:1; /** The request was aborted */ unsigned aborted:1; /** Request is sent in the background */ unsigned background:1; /** The request has been interrupted */ unsigned interrupted:1; /** Data is being copied to/from the request */ unsigned locked:1; /** Request is counted as "waiting" */ unsigned waiting:1; /** State of the request */ enum fuse_req_state state; /** The request input */ struct fuse_in in; /** The request output */ struct fuse_out out; /** Used to wake up the task waiting for completion of request*/ wait_queue_head_t waitq; /** Data for asynchronous requests */ union { struct fuse_forget_in forget_in; struct fuse_release_in release_in; struct fuse_init_in init_in; struct fuse_init_out init_out; struct fuse_read_in read_in; struct fuse_lk_in lk_in; } misc; /** page vector */ struct page *pages[FUSE_MAX_PAGES_PER_REQ]; /** number of pages in vector */ unsigned num_pages; /** offset of data on first page */ unsigned page_offset; /** File used in the request (or NULL) */ struct fuse_file *ff; /** vfsmount used in release */ struct vfsmount *vfsmount; /** dentry used in release */ struct dentry *dentry; /** Request completion callback */ void (*end)(struct fuse_conn *, struct fuse_req *); /** Request is stolen from fuse_file->reserved_req */ struct file *stolen_file; }; /** * A Fuse connection. * * This structure is created, when the filesystem is mounted, and is * destroyed, when the client device is closed and the filesystem is * unmounted. */ struct fuse_conn { /** Lock protecting accessess to members of this structure */ spinlock_t lock; /** Mutex protecting against directory alias creation */ struct mutex inst_mutex; /** Refcount */ atomic_t count; /** The user id for this mount */ uid_t user_id; /** The group id for this mount */ gid_t group_id; /** The fuse mount flags for this mount */ unsigned flags; /** Maximum read size */ unsigned max_read; /** Maximum write size */ unsigned max_write; /** Readers of the connection are waiting on this */ wait_queue_head_t waitq; /** The list of pending requests */ struct list_head pending; /** The list of requests being processed */ struct list_head processing; /** The list of requests under I/O */ struct list_head io; /** Number of requests currently in the background */ unsigned num_background; /** Pending interrupts */ struct list_head interrupts; /** Flag indicating if connection is blocked. This will be the case before the INIT reply is received, and if there are too many outstading backgrounds requests */ int blocked; /** waitq for blocked connection */ wait_queue_head_t blocked_waitq; /** waitq for reserved requests */ wait_queue_head_t reserved_req_waitq; /** The next unique request id */ u64 reqctr; /** Connection established, cleared on umount, connection abort and device release */ unsigned connected; /** Connection failed (version mismatch). Cannot race with setting other bitfields since it is only set once in INIT reply, before any other request, and never cleared */ unsigned conn_error : 1; /** Connection successful. Only set in INIT */ unsigned conn_init : 1; /** Do readpages asynchronously? Only set in INIT */ unsigned async_read : 1; /* * The following bitfields are only for optimization purposes * and hence races in setting them will not cause malfunction */ /** Is fsync not implemented by fs? */ unsigned no_fsync : 1; /** Is fsyncdir not implemented by fs? */ unsigned no_fsyncdir : 1; /** Is flush not implemented by fs? */ unsigned no_flush : 1; /** Is setxattr not implemented by fs? */ unsigned no_setxattr : 1; /** Is getxattr not implemented by fs? */ unsigned no_getxattr : 1; /** Is listxattr not implemented by fs? */ unsigned no_listxattr : 1; /** Is removexattr not implemented by fs? */ unsigned no_removexattr : 1; /** Are file locking primitives not implemented by fs? */ unsigned no_lock : 1; /** Is access not implemented by fs? */ unsigned no_access : 1; /** Is create not implemented by fs? */ unsigned no_create : 1; /** Is interrupt not implemented by fs? */ unsigned no_interrupt : 1; /** Is bmap not implemented by fs? */ unsigned no_bmap : 1; /** The number of requests waiting for completion */ atomic_t num_waiting; /** Negotiated minor version */ unsigned minor; /** Backing dev info */ struct backing_dev_info bdi; /** Entry on the fuse_conn_list */ struct list_head entry; /** Unique ID */ u64 id; /** Dentries in the control filesystem */ struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES]; /** number of dentries used in the above array */ int ctl_ndents; /** O_ASYNC requests */ struct fasync_struct *fasync; /** Key for lock owner ID scrambling */ u32 scramble_key[4]; /** Reserved request for the DESTROY message */ struct fuse_req *destroy_req; /** Version counter for attribute changes */ u64 attr_version; }; static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) { return sb->s_fs_info; } static inline struct fuse_conn *get_fuse_conn(struct inode *inode) { return get_fuse_conn_super(inode->i_sb); } static inline struct fuse_inode *get_fuse_inode(struct inode *inode) { return container_of(inode, struct fuse_inode, inode); } static inline u64 get_node_id(struct inode *inode) { return get_fuse_inode(inode)->nodeid; } /** Device operations */ extern const struct file_operations fuse_dev_operations; /** * Get a filled in inode */ struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, int generation, struct fuse_attr *attr, u64 attr_valid, u64 attr_version); /** * Send FORGET command */ void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, unsigned long nodeid, u64 nlookup); /** * Initialize READ or READDIR request */ void fuse_read_fill(struct fuse_req *req, struct fuse_file *ff, struct inode *inode, loff_t pos, size_t count, int opcode); /** * Send OPEN or OPENDIR request */ int fuse_open_common(struct inode *inode, struct file *file, int isdir); struct fuse_file *fuse_file_alloc(void); void fuse_file_free(struct fuse_file *ff); void fuse_finish_open(struct inode *inode, struct file *file, struct fuse_file *ff, struct fuse_open_out *outarg); /** Fill in ff->reserved_req with a RELEASE request */ void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode); /** * Send RELEASE or RELEASEDIR request */ int fuse_release_common(struct inode *inode, struct file *file, int isdir); /** * Send FSYNC or FSYNCDIR request */ int fuse_fsync_common(struct file *file, struct dentry *de, int datasync, int isdir); /** * Initialize file operations on a regular file */ void fuse_init_file_inode(struct inode *inode); /** * Initialize inode operations on regular files and special files */ void fuse_init_common(struct inode *inode); /** * Initialize inode and file operations on a directory */ void fuse_init_dir(struct inode *inode); /** * Initialize inode operations on a symlink */ void fuse_init_symlink(struct inode *inode); /** * Change attributes of an inode */ void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, u64 attr_valid, u64 attr_version); /** * Initialize the client device */ int fuse_dev_init(void); /** * Cleanup the client device */ void fuse_dev_cleanup(void); int fuse_ctl_init(void); void fuse_ctl_cleanup(void); /** * Allocate a request */ struct fuse_req *fuse_request_alloc(void); /** * Free a request */ void fuse_request_free(struct fuse_req *req); /** * Get a request, may fail with -ENOMEM */ struct fuse_req *fuse_get_req(struct fuse_conn *fc); /** * Gets a requests for a file operation, always succeeds */ struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file); /** * Decrement reference count of a request. If count goes to zero free * the request. */ void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); /** * Send a request (synchronous) */ void request_send(struct fuse_conn *fc, struct fuse_req *req); /** * Send a request with no reply */ void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); /** * Send a request in the background */ void request_send_background(struct fuse_conn *fc, struct fuse_req *req); /* Abort all requests */ void fuse_abort_conn(struct fuse_conn *fc); /** * Invalidate inode attributes */ void fuse_invalidate_attr(struct inode *inode); /** * Acquire reference to fuse_conn */ struct fuse_conn *fuse_conn_get(struct fuse_conn *fc); /** * Release reference to fuse_conn */ void fuse_conn_put(struct fuse_conn *fc); /** * Add connection to control filesystem */ int fuse_ctl_add_conn(struct fuse_conn *fc); /** * Remove connection from control filesystem */ void fuse_ctl_remove_conn(struct fuse_conn *fc); /** * Is file type valid? */ int fuse_valid_type(int m); /** * Is task allowed to perform filesystem operation? */ int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);