2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
5 This program can be distributed under the terms of the GNU GPL.
12 #include <linux/fuse.h>
14 #include <linux/mount.h>
15 #include <linux/wait.h>
16 #include <linux/list.h>
17 #include <linux/spinlock.h>
19 #include <linux/backing-dev.h>
20 #include <linux/mutex.h>
21 #include <linux/rwsem.h>
22 #include <linux/rbtree.h>
23 #include <linux/poll.h>
24 #include <linux/workqueue.h>
26 /** Max number of pages that can be used in a single read request */
27 #define FUSE_MAX_PAGES_PER_REQ 32
29 /** Bias for fi->writectr, meaning new writepages must not be sent */
30 #define FUSE_NOWRITE INT_MIN
32 /** It could be as large as PATH_MAX, but would that have any uses? */
33 #define FUSE_NAME_MAX 1024
35 /** Number of dentries for each connection in the control filesystem */
36 #define FUSE_CTL_NUM_DENTRIES 5
38 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
39 module will check permissions based on the file mode. Otherwise no
40 permission checking is done in the kernel */
41 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
43 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
44 doing the mount will be allowed to access the filesystem */
45 #define FUSE_ALLOW_OTHER (1 << 1)
47 /** Number of page pointers embedded in fuse_req */
48 #define FUSE_REQ_INLINE_PAGES 1
50 /** List of active connections */
51 extern struct list_head fuse_conn_list;
53 /** Global mutex protecting fuse_conn_list and the control filesystem */
54 extern struct mutex fuse_mutex;
56 /** Module parameters */
57 extern unsigned max_user_bgreq;
58 extern unsigned max_user_congthresh;
60 /* One forget request */
61 struct fuse_forget_link {
62 struct fuse_forget_one forget_one;
63 struct fuse_forget_link *next;
71 /** Unique ID, which identifies the inode between userspace
75 /** Number of lookups on this inode */
78 /** The request used for sending the FORGET message */
79 struct fuse_forget_link *forget;
81 /** Time in jiffies until the file attributes are valid */
84 /** The sticky bit in inode->i_mode may have been removed, so
85 preserve the original mode */
88 /** 64 bit inode number */
91 /** Version of last attribute change */
94 /** Files usable in writepage. Protected by fc->lock */
95 struct list_head write_files;
97 /** Writepages pending on truncate or fsync */
98 struct list_head queued_writes;
100 /** Number of sent writes, a negative bias (FUSE_NOWRITE)
101 * means more writes are blocked */
104 /** Waitq for writepage completion */
105 wait_queue_head_t page_waitq;
107 /** List of writepage requestst (pending or sent) */
108 struct list_head writepages;
110 /** Miscellaneous bits describing inode state */
114 /** FUSE inode state bits */
116 /** Advise readdirplus */
117 FUSE_I_ADVISE_RDPLUS,
118 /** Initialized with readdirplus */
120 /** An operation changing file size is in progress */
121 FUSE_I_SIZE_UNSTABLE,
126 /** FUSE specific file data */
128 /** Fuse connection for this file */
129 struct fuse_conn *fc;
131 /** Request reserved for flush and release */
132 struct fuse_req *reserved_req;
134 /** Kernel file handle guaranteed to be unique */
137 /** File handle used by userspace */
140 /** Node id of this file */
146 /** FOPEN_* flags returned by open */
149 /** Entry on inode's write_files list */
150 struct list_head write_entry;
152 /** RB node to be linked on fuse_conn->polled_files */
153 struct rb_node polled_node;
155 /** Wait queue head for poll */
156 wait_queue_head_t poll_wait;
158 /** Has flock been performed on this file? */
162 /** One input argument of a request */
168 /** The request input */
170 /** The request header */
171 struct fuse_in_header h;
173 /** True if the data for the last argument is in req->pages */
176 /** Number of arguments */
179 /** Array of arguments */
180 struct fuse_in_arg args[3];
183 /** One output argument of a request */
189 /** The request output */
191 /** Header returned from userspace */
192 struct fuse_out_header h;
195 * The following bitfields are not changed during the request
199 /** Last argument is variable length (can be shorter than
203 /** Last argument is a list of pages to copy data to */
206 /** Zero partially or not copied pages */
207 unsigned page_zeroing:1;
209 /** Pages may be replaced with new ones */
210 unsigned page_replace:1;
212 /** Number or arguments */
215 /** Array of arguments */
216 struct fuse_arg args[2];
219 /** FUSE page descriptor */
220 struct fuse_page_desc {
232 struct fuse_in_arg args[3];
238 struct fuse_arg args[2];
242 #define FUSE_ARGS(args) struct fuse_args args = {}
244 /** The request IO state (for asynchronous processing) */
245 struct fuse_io_priv {
256 struct completion *done;
262 * FR_ISREPLY: set if the request has reply
263 * FR_FORCE: force sending of the request even if interrupted
264 * FR_BACKGROUND: request is sent in the background
265 * FR_WAITING: request is counted as "waiting"
266 * FR_ABORTED: the request was aborted
267 * FR_INTERRUPTED: the request has been interrupted
268 * FR_LOCKED: data is being copied to/from the request
269 * FR_PENDING: request is not yet in userspace
270 * FR_SENT: request is in userspace, waiting for an answer
271 * FR_FINISHED: request is finished
272 * FR_PRIVATE: request is on private list
289 * A request to the client
291 * .waitq.lock protects the following fields:
293 * - FR_LOCKED (may also be modified under fc->lock, tested under both)
296 /** This can be on either pending processing or io lists in
298 struct list_head list;
300 /** Entry on the interrupts list */
301 struct list_head intr_entry;
306 /** Unique ID for the interrupt request */
309 /* Request flags, updated with test/set/clear_bit() */
312 /** The request input */
315 /** The request output */
318 /** Used to wake up the task waiting for completion of request*/
319 wait_queue_head_t waitq;
321 /** Data for asynchronous requests */
324 struct fuse_release_in in;
327 struct fuse_init_in init_in;
328 struct fuse_init_out init_out;
329 struct cuse_init_in cuse_init_in;
331 struct fuse_read_in in;
335 struct fuse_write_in in;
336 struct fuse_write_out out;
337 struct fuse_req *next;
339 struct fuse_notify_retrieve_in retrieve_in;
345 /** page-descriptor vector */
346 struct fuse_page_desc *page_descs;
348 /** size of the 'pages' array */
351 /** inline page vector */
352 struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
354 /** inline page-descriptor vector */
355 struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
357 /** number of pages in vector */
360 /** File used in the request (or NULL) */
361 struct fuse_file *ff;
363 /** Inode used in the request or NULL */
366 /** AIO control block */
367 struct fuse_io_priv *io;
369 /** Link on fi->writepages */
370 struct list_head writepages_entry;
372 /** Request completion callback */
373 void (*end)(struct fuse_conn *, struct fuse_req *);
375 /** Request is stolen from fuse_file->reserved_req */
376 struct file *stolen_file;
380 /** Connection established */
383 /** Readers of the connection are waiting on this */
384 wait_queue_head_t waitq;
386 /** The next unique request id */
389 /** The list of pending requests */
390 struct list_head pending;
392 /** Pending interrupts */
393 struct list_head interrupts;
395 /** Queue of pending forgets */
396 struct fuse_forget_link forget_list_head;
397 struct fuse_forget_link *forget_list_tail;
399 /** Batching of FORGET requests (positive indicates FORGET batch) */
402 /** O_ASYNC requests */
403 struct fasync_struct *fasync;
407 /** Connection established */
410 /** Lock protecting accessess to members of this structure */
413 /** The list of requests being processed */
414 struct list_head processing;
416 /** The list of requests under I/O */
421 * Fuse device instance
424 /** Fuse connection for this device */
425 struct fuse_conn *fc;
427 /** Processing queue */
428 struct fuse_pqueue pq;
430 /** list entry on fc->devices */
431 struct list_head entry;
437 * This structure is created, when the filesystem is mounted, and is
438 * destroyed, when the client device is closed and the filesystem is
442 /** Lock protecting accessess to members of this structure */
448 /** Number of fuse_dev's */
453 /** The user id for this mount */
456 /** The group id for this mount */
459 /** The fuse mount flags for this mount */
462 /** Maximum read size */
465 /** Maximum write size */
469 struct fuse_iqueue iq;
471 /** The next unique kernel file handle */
474 /** rbtree of fuse_files waiting for poll events indexed by ph */
475 struct rb_root polled_files;
477 /** Maximum number of outstanding background requests */
478 unsigned max_background;
480 /** Number of background requests at which congestion starts */
481 unsigned congestion_threshold;
483 /** Number of requests currently in the background */
484 unsigned num_background;
486 /** Number of background requests currently queued for userspace */
487 unsigned active_background;
489 /** The list of background requests set aside for later queuing */
490 struct list_head bg_queue;
492 /** Flag indicating that INIT reply has been received. Allocating
493 * any fuse request will be suspended until the flag is set */
496 /** Flag indicating if connection is blocked. This will be
497 the case before the INIT reply is received, and if there
498 are too many outstading backgrounds requests */
501 /** waitq for blocked connection */
502 wait_queue_head_t blocked_waitq;
504 /** waitq for reserved requests */
505 wait_queue_head_t reserved_req_waitq;
507 /** Connection established, cleared on umount, connection
508 abort and device release */
511 /** Connection failed (version mismatch). Cannot race with
512 setting other bitfields since it is only set once in INIT
513 reply, before any other request, and never cleared */
514 unsigned conn_error:1;
516 /** Connection successful. Only set in INIT */
517 unsigned conn_init:1;
519 /** Do readpages asynchronously? Only set in INIT */
520 unsigned async_read:1;
522 /** Do not send separate SETATTR request before open(O_TRUNC) */
523 unsigned atomic_o_trunc:1;
525 /** Filesystem supports NFS exporting. Only set in INIT */
526 unsigned export_support:1;
528 /** Set if bdi is valid */
529 unsigned bdi_initialized:1;
531 /** write-back cache policy (default is write-through) */
532 unsigned writeback_cache:1;
535 * The following bitfields are only for optimization purposes
536 * and hence races in setting them will not cause malfunction
539 /** Is open/release not implemented by fs? */
542 /** Is fsync not implemented by fs? */
545 /** Is fsyncdir not implemented by fs? */
546 unsigned no_fsyncdir:1;
548 /** Is flush not implemented by fs? */
551 /** Is setxattr not implemented by fs? */
552 unsigned no_setxattr:1;
554 /** Is getxattr not implemented by fs? */
555 unsigned no_getxattr:1;
557 /** Is listxattr not implemented by fs? */
558 unsigned no_listxattr:1;
560 /** Is removexattr not implemented by fs? */
561 unsigned no_removexattr:1;
563 /** Are posix file locking primitives not implemented by fs? */
566 /** Is access not implemented by fs? */
567 unsigned no_access:1;
569 /** Is create not implemented by fs? */
570 unsigned no_create:1;
572 /** Is interrupt not implemented by fs? */
573 unsigned no_interrupt:1;
575 /** Is bmap not implemented by fs? */
578 /** Is poll not implemented by fs? */
581 /** Do multi-page cached writes */
582 unsigned big_writes:1;
584 /** Don't apply umask to creation modes */
585 unsigned dont_mask:1;
587 /** Are BSD file locking primitives not implemented by fs? */
590 /** Is fallocate not implemented by fs? */
591 unsigned no_fallocate:1;
593 /** Is rename with flags implemented by fs? */
594 unsigned no_rename2:1;
596 /** Use enhanced/automatic page cache invalidation. */
597 unsigned auto_inval_data:1;
599 /** Does the filesystem support readdirplus? */
600 unsigned do_readdirplus:1;
602 /** Does the filesystem want adaptive readdirplus? */
603 unsigned readdirplus_auto:1;
605 /** Does the filesystem support asynchronous direct-IO submission? */
606 unsigned async_dio:1;
608 /** The number of requests waiting for completion */
609 atomic_t num_waiting;
611 /** Negotiated minor version */
614 /** Backing dev info */
615 struct backing_dev_info bdi;
617 /** Entry on the fuse_conn_list */
618 struct list_head entry;
620 /** Device ID from super block */
623 /** Dentries in the control filesystem */
624 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
626 /** number of dentries used in the above array */
629 /** Key for lock owner ID scrambling */
632 /** Reserved request for the DESTROY message */
633 struct fuse_req *destroy_req;
635 /** Version counter for attribute changes */
638 /** Called on final put */
639 void (*release)(struct fuse_conn *);
641 /** Super block for this connection. */
642 struct super_block *sb;
644 /** Read/write semaphore to hold when accessing sb. */
645 struct rw_semaphore killsb;
647 /** List of device instances belonging to this connection */
648 struct list_head devices;
651 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
653 return sb->s_fs_info;
656 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
658 return get_fuse_conn_super(inode->i_sb);
661 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
663 return container_of(inode, struct fuse_inode, inode);
666 static inline u64 get_node_id(struct inode *inode)
668 return get_fuse_inode(inode)->nodeid;
671 /** Device operations */
672 extern const struct file_operations fuse_dev_operations;
674 extern const struct dentry_operations fuse_dentry_operations;
677 * Inode to nodeid comparison.
679 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
682 * Get a filled in inode
684 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
685 int generation, struct fuse_attr *attr,
686 u64 attr_valid, u64 attr_version);
688 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
689 struct fuse_entry_out *outarg, struct inode **inode);
692 * Send FORGET command
694 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
695 u64 nodeid, u64 nlookup);
697 struct fuse_forget_link *fuse_alloc_forget(void);
699 /* Used by READDIRPLUS */
700 void fuse_force_forget(struct file *file, u64 nodeid);
703 * Initialize READ or READDIR request
705 void fuse_read_fill(struct fuse_req *req, struct file *file,
706 loff_t pos, size_t count, int opcode);
709 * Send OPEN or OPENDIR request
711 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
713 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
714 struct fuse_file *fuse_file_get(struct fuse_file *ff);
715 void fuse_file_free(struct fuse_file *ff);
716 void fuse_finish_open(struct inode *inode, struct file *file);
718 void fuse_sync_release(struct fuse_file *ff, int flags);
721 * Send RELEASE or RELEASEDIR request
723 void fuse_release_common(struct file *file, int opcode);
726 * Send FSYNC or FSYNCDIR request
728 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
729 int datasync, int isdir);
734 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
735 struct fuse_notify_poll_wakeup_out *outarg);
738 * Initialize file operations on a regular file
740 void fuse_init_file_inode(struct inode *inode);
743 * Initialize inode operations on regular files and special files
745 void fuse_init_common(struct inode *inode);
748 * Initialize inode and file operations on a directory
750 void fuse_init_dir(struct inode *inode);
753 * Initialize inode operations on a symlink
755 void fuse_init_symlink(struct inode *inode);
758 * Change attributes of an inode
760 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
761 u64 attr_valid, u64 attr_version);
763 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
767 * Initialize the client device
769 int fuse_dev_init(void);
772 * Cleanup the client device
774 void fuse_dev_cleanup(void);
776 int fuse_ctl_init(void);
777 void __exit fuse_ctl_cleanup(void);
782 struct fuse_req *fuse_request_alloc(unsigned npages);
784 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
789 void fuse_request_free(struct fuse_req *req);
792 * Get a request, may fail with -ENOMEM,
793 * caller should specify # elements in req->pages[] explicitly
795 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
796 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
800 * Increment reference count on request
802 void __fuse_get_request(struct fuse_req *req);
805 * Gets a requests for a file operation, always succeeds
807 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
811 * Decrement reference count of a request. If count goes to zero free
814 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
817 * Send a request (synchronous)
819 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
822 * Simple request sending that does request allocation and freeing
824 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
827 * Send a request in the background
829 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
831 void fuse_request_send_background_locked(struct fuse_conn *fc,
832 struct fuse_req *req);
834 /* Abort all requests */
835 void fuse_abort_conn(struct fuse_conn *fc);
838 * Invalidate inode attributes
840 void fuse_invalidate_attr(struct inode *inode);
842 void fuse_invalidate_entry_cache(struct dentry *entry);
844 void fuse_invalidate_atime(struct inode *inode);
847 * Acquire reference to fuse_conn
849 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
852 * Initialize fuse_conn
854 void fuse_conn_init(struct fuse_conn *fc);
857 * Release reference to fuse_conn
859 void fuse_conn_put(struct fuse_conn *fc);
861 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
862 void fuse_dev_free(struct fuse_dev *fud);
865 * Add connection to control filesystem
867 int fuse_ctl_add_conn(struct fuse_conn *fc);
870 * Remove connection from control filesystem
872 void fuse_ctl_remove_conn(struct fuse_conn *fc);
875 * Is file type valid?
877 int fuse_valid_type(int m);
880 * Is current process allowed to perform filesystem operation?
882 int fuse_allow_current_process(struct fuse_conn *fc);
884 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
886 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
887 struct file *file, bool *refreshed);
889 void fuse_flush_writepages(struct inode *inode);
891 void fuse_set_nowrite(struct inode *inode);
892 void fuse_release_nowrite(struct inode *inode);
894 u64 fuse_get_attr_version(struct fuse_conn *fc);
897 * File-system tells the kernel to invalidate cache for the given node id.
899 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
900 loff_t offset, loff_t len);
903 * File-system tells the kernel to invalidate parent attributes and
904 * the dentry matching parent/name.
906 * If the child_nodeid is non-zero and:
907 * - matches the inode number for the dentry matching parent/name,
908 * - is not a mount point
909 * - is a file or oan empty directory
910 * then the dentry is unhashed (d_delete()).
912 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
913 u64 child_nodeid, struct qstr *name);
915 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
919 * fuse_direct_io() flags
922 /** If set, it is WRITE; otherwise - READ */
923 #define FUSE_DIO_WRITE (1 << 0)
925 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
926 #define FUSE_DIO_CUSE (1 << 1)
928 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
929 loff_t *ppos, int flags);
930 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
932 long fuse_ioctl_common(struct file *file, unsigned int cmd,
933 unsigned long arg, unsigned int flags);
934 unsigned fuse_file_poll(struct file *file, poll_table *wait);
935 int fuse_dev_release(struct inode *inode, struct file *file);
937 bool fuse_write_update_size(struct inode *inode, loff_t pos);
939 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
940 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
942 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
945 void fuse_set_initialized(struct fuse_conn *fc);
947 #endif /* _FS_FUSE_I_H */