| /* |
| FUSE: Filesystem in Userspace |
| Copyright (C) 2001-2005 Miklos Szeredi <miklos@szeredi.hu> |
| |
| This program can be distributed under the terms of the GNU GPL. |
| See the file COPYING. |
| */ |
| |
| #include <linux/fuse.h> |
| #include <linux/fs.h> |
| #include <linux/wait.h> |
| #include <linux/list.h> |
| #include <linux/spinlock.h> |
| #include <linux/mm.h> |
| #include <linux/backing-dev.h> |
| #include <asm/semaphore.h> |
| |
| /** Max number of pages that can be used in a single read request */ |
| #define FUSE_MAX_PAGES_PER_REQ 32 |
| |
| /** If more requests are outstanding, then the operation will block */ |
| #define FUSE_MAX_OUTSTANDING 10 |
| |
| /** 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) |
| |
| |
| /** 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 */ |
| unsigned long i_time; |
| }; |
| |
| /** FUSE specific file data */ |
| struct fuse_file { |
| /** Request reserved for flush and release */ |
| struct fuse_req *release_req; |
| |
| /** File handle used by userspace */ |
| u64 fh; |
| }; |
| |
| /** 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; |
| |
| /** 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]; |
| }; |
| |
| struct fuse_req; |
| struct fuse_conn; |
| |
| /** |
| * A request to the client |
| */ |
| struct fuse_req { |
| /** This can be on either unused_list, pending or processing |
| lists in fuse_conn */ |
| struct list_head list; |
| |
| /** Entry on the background list */ |
| struct list_head bg_entry; |
| |
| /** refcount */ |
| atomic_t count; |
| |
| /** True if the request has reply */ |
| unsigned isreply:1; |
| |
| /** The request is preallocated */ |
| unsigned preallocated:1; |
| |
| /** The request was interrupted */ |
| unsigned interrupted:1; |
| |
| /** Request is sent in the background */ |
| unsigned background:1; |
| |
| /** Data is being copied to/from the request */ |
| unsigned locked:1; |
| |
| /** Request has been sent to userspace */ |
| unsigned sent:1; |
| |
| /** The request is finished */ |
| unsigned finished:1; |
| |
| /** 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_out init_in_out; |
| } 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; |
| |
| /** Inode used in the request */ |
| struct inode *inode; |
| |
| /** Second inode used in the request (or NULL) */ |
| struct inode *inode2; |
| |
| /** File used in the request (or NULL) */ |
| struct file *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 { |
| /** Reference count */ |
| int 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; |
| |
| /** Requests put in the background (RELEASE or any other |
| interrupted request) */ |
| struct list_head background; |
| |
| /** Controls the maximum number of outstanding requests */ |
| struct semaphore outstanding_sem; |
| |
| /** This counts the number of outstanding requests if |
| outstanding_sem would go negative */ |
| unsigned outstanding_debt; |
| |
| /** RW semaphore for exclusion with fuse_put_super() */ |
| struct rw_semaphore sbput_sem; |
| |
| /** The list of unused requests */ |
| struct list_head unused_list; |
| |
| /** The next unique request id */ |
| u64 reqctr; |
| |
| /** Mount is active */ |
| unsigned mounted : 1; |
| |
| /** Connection established */ |
| unsigned connected : 1; |
| |
| /** Connection failed (version mismatch) */ |
| unsigned conn_error : 1; |
| |
| /** 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; |
| |
| /** Backing dev info */ |
| struct backing_dev_info bdi; |
| }; |
| |
| static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb) |
| { |
| return (struct fuse_conn **) &sb->s_fs_info; |
| } |
| |
| static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) |
| { |
| return *get_fuse_conn_super_p(sb); |
| } |
| |
| 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 struct file_operations fuse_dev_operations; |
| |
| /** |
| * This is the single global spinlock which protects FUSE's structures |
| * |
| * The following data is protected by this lock: |
| * |
| * - the private_data field of the device file |
| * - the s_fs_info field of the super block |
| * - unused_list, pending, processing lists in fuse_conn |
| * - background list in fuse_conn |
| * - the unique request ID counter reqctr in fuse_conn |
| * - the sb (super_block) field in fuse_conn |
| * - the file (device file) field in fuse_conn |
| */ |
| extern spinlock_t fuse_lock; |
| |
| /** |
| * Get a filled in inode |
| */ |
| struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, |
| int generation, struct fuse_attr *attr); |
| |
| /** |
| * Send FORGET command |
| */ |
| void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, |
| unsigned long nodeid, u64 nlookup); |
| |
| /** |
| * Send READ or READDIR request |
| */ |
| size_t fuse_send_read_common(struct fuse_req *req, struct file *file, |
| struct inode *inode, loff_t pos, size_t count, |
| int isdir); |
| |
| /** |
| * Send OPEN or OPENDIR request |
| */ |
| int fuse_open_common(struct inode *inode, struct file *file, int isdir); |
| |
| /** |
| * 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); |
| |
| /** |
| * Initialise file operations on a regular file |
| */ |
| void fuse_init_file_inode(struct inode *inode); |
| |
| /** |
| * Initialise inode operations on regular files and special files |
| */ |
| void fuse_init_common(struct inode *inode); |
| |
| /** |
| * Initialise inode and file operations on a directory |
| */ |
| void fuse_init_dir(struct inode *inode); |
| |
| /** |
| * Initialise 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); |
| |
| /** |
| * Check if the connection can be released, and if yes, then free the |
| * connection structure |
| */ |
| void fuse_release_conn(struct fuse_conn *fc); |
| |
| /** |
| * Initialize the client device |
| */ |
| int fuse_dev_init(void); |
| |
| /** |
| * Cleanup the client device |
| */ |
| void fuse_dev_cleanup(void); |
| |
| /** |
| * Allocate a request |
| */ |
| struct fuse_req *fuse_request_alloc(void); |
| |
| /** |
| * Free a request |
| */ |
| void fuse_request_free(struct fuse_req *req); |
| |
| /** |
| * Reinitialize a request, the preallocated flag is left unmodified |
| */ |
| void fuse_reset_request(struct fuse_req *req); |
| |
| /** |
| * Reserve a preallocated request |
| */ |
| struct fuse_req *fuse_get_request(struct fuse_conn *fc); |
| |
| /** |
| * Reserve a preallocated request, only interruptible by SIGKILL |
| */ |
| struct fuse_req *fuse_get_request_nonint(struct fuse_conn *fc); |
| |
| /** |
| * Decrement reference count of a request. If count goes to zero put |
| * on unused list (preallocated) or free reqest (not preallocated). |
| */ |
| void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); |
| |
| /** |
| * Send a request (synchronous, interruptible) |
| */ |
| void request_send(struct fuse_conn *fc, struct fuse_req *req); |
| |
| /** |
| * Send a request (synchronous, non-interruptible except by SIGKILL) |
| */ |
| void request_send_nonint(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); |
| |
| /** |
| * Release inodes and file assiciated with background request |
| */ |
| void fuse_release_background(struct fuse_req *req); |
| |
| /** |
| * Get the attributes of a file |
| */ |
| int fuse_do_getattr(struct inode *inode); |
| |
| /** |
| * Invalidate inode attributes |
| */ |
| void fuse_invalidate_attr(struct inode *inode); |
| |
| /** |
| * Send the INIT message |
| */ |
| void fuse_send_init(struct fuse_conn *fc); |