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
,
122 /** FUSE specific file data */
124 /** Fuse connection for this file */
125 struct fuse_conn
*fc
;
127 /** Request reserved for flush and release */
128 struct fuse_req
*reserved_req
;
130 /** Kernel file handle guaranteed to be unique */
133 /** File handle used by userspace */
136 /** Node id of this file */
142 /** FOPEN_* flags returned by open */
145 /** Entry on inode's write_files list */
146 struct list_head write_entry
;
148 /** RB node to be linked on fuse_conn->polled_files */
149 struct rb_node polled_node
;
151 /** Wait queue head for poll */
152 wait_queue_head_t poll_wait
;
154 /** Has flock been performed on this file? */
158 /** One input argument of a request */
164 /** The request input */
166 /** The request header */
167 struct fuse_in_header h
;
169 /** True if the data for the last argument is in req->pages */
172 /** Number of arguments */
175 /** Array of arguments */
176 struct fuse_in_arg args
[3];
179 /** One output argument of a request */
185 /** The request output */
187 /** Header returned from userspace */
188 struct fuse_out_header h
;
191 * The following bitfields are not changed during the request
195 /** Last argument is variable length (can be shorter than
199 /** Last argument is a list of pages to copy data to */
202 /** Zero partially or not copied pages */
203 unsigned page_zeroing
:1;
205 /** Pages may be replaced with new ones */
206 unsigned page_replace
:1;
208 /** Number or arguments */
211 /** Array of arguments */
212 struct fuse_arg args
[3];
215 /** FUSE page descriptor */
216 struct fuse_page_desc
{
221 /** The request state */
222 enum fuse_req_state
{
231 /** The request IO state (for asynchronous processing) */
232 struct fuse_io_priv
{
246 * A request to the client
249 /** This can be on either pending processing or io lists in
251 struct list_head list
;
253 /** Entry on the interrupts list */
254 struct list_head intr_entry
;
259 /** Unique ID for the interrupt request */
263 * The following bitfields are either set once before the
264 * request is queued or setting/clearing them is protected by
268 /** True if the request has reply */
271 /** Force sending of the request even if interrupted */
274 /** The request was aborted */
277 /** Request is sent in the background */
278 unsigned background
:1;
280 /** The request has been interrupted */
281 unsigned interrupted
:1;
283 /** Data is being copied to/from the request */
286 /** Request is counted as "waiting" */
289 /** State of the request */
290 enum fuse_req_state state
;
292 /** The request input */
295 /** The request output */
298 /** Used to wake up the task waiting for completion of request*/
299 wait_queue_head_t waitq
;
301 /** Data for asynchronous requests */
305 struct fuse_release_in in
;
306 struct work_struct work
;
310 struct fuse_init_in init_in
;
311 struct fuse_init_out init_out
;
312 struct cuse_init_in cuse_init_in
;
314 struct fuse_read_in in
;
318 struct fuse_write_in in
;
319 struct fuse_write_out out
;
321 struct fuse_notify_retrieve_in retrieve_in
;
322 struct fuse_lk_in lk_in
;
328 /** page-descriptor vector */
329 struct fuse_page_desc
*page_descs
;
331 /** size of the 'pages' array */
334 /** inline page vector */
335 struct page
*inline_pages
[FUSE_REQ_INLINE_PAGES
];
337 /** inline page-descriptor vector */
338 struct fuse_page_desc inline_page_descs
[FUSE_REQ_INLINE_PAGES
];
340 /** number of pages in vector */
343 /** File used in the request (or NULL) */
344 struct fuse_file
*ff
;
346 /** Inode used in the request or NULL */
349 /** AIO control block */
350 struct fuse_io_priv
*io
;
352 /** Link on fi->writepages */
353 struct list_head writepages_entry
;
355 /** Request completion callback */
356 void (*end
)(struct fuse_conn
*, struct fuse_req
*);
358 /** Request is stolen from fuse_file->reserved_req */
359 struct file
*stolen_file
;
365 * This structure is created, when the filesystem is mounted, and is
366 * destroyed, when the client device is closed and the filesystem is
370 /** Lock protecting accessess to members of this structure */
373 /** Mutex protecting against directory alias creation */
374 struct mutex inst_mutex
;
379 /** The user id for this mount */
382 /** The group id for this mount */
385 /** The fuse mount flags for this mount */
388 /** Maximum read size */
391 /** Maximum write size */
394 /** Readers of the connection are waiting on this */
395 wait_queue_head_t waitq
;
397 /** The list of pending requests */
398 struct list_head pending
;
400 /** The list of requests being processed */
401 struct list_head processing
;
403 /** The list of requests under I/O */
406 /** The next unique kernel file handle */
409 /** rbtree of fuse_files waiting for poll events indexed by ph */
410 struct rb_root polled_files
;
412 /** Maximum number of outstanding background requests */
413 unsigned max_background
;
415 /** Number of background requests at which congestion starts */
416 unsigned congestion_threshold
;
418 /** Number of requests currently in the background */
419 unsigned num_background
;
421 /** Number of background requests currently queued for userspace */
422 unsigned active_background
;
424 /** The list of background requests set aside for later queuing */
425 struct list_head bg_queue
;
427 /** Pending interrupts */
428 struct list_head interrupts
;
430 /** Queue of pending forgets */
431 struct fuse_forget_link forget_list_head
;
432 struct fuse_forget_link
*forget_list_tail
;
434 /** Batching of FORGET requests (positive indicates FORGET batch) */
437 /** Flag indicating that INIT reply has been received. Allocating
438 * any fuse request will be suspended until the flag is set */
441 /** Flag indicating if connection is blocked. This will be
442 the case before the INIT reply is received, and if there
443 are too many outstading backgrounds requests */
446 /** waitq for blocked connection */
447 wait_queue_head_t blocked_waitq
;
449 /** waitq for reserved requests */
450 wait_queue_head_t reserved_req_waitq
;
452 /** The next unique request id */
455 /** Connection established, cleared on umount, connection
456 abort and device release */
459 /** Connection failed (version mismatch). Cannot race with
460 setting other bitfields since it is only set once in INIT
461 reply, before any other request, and never cleared */
462 unsigned conn_error
:1;
464 /** Connection successful. Only set in INIT */
465 unsigned conn_init
:1;
467 /** Do readpages asynchronously? Only set in INIT */
468 unsigned async_read
:1;
470 /** Do not send separate SETATTR request before open(O_TRUNC) */
471 unsigned atomic_o_trunc
:1;
473 /** Filesystem supports NFS exporting. Only set in INIT */
474 unsigned export_support
:1;
476 /** Set if bdi is valid */
477 unsigned bdi_initialized
:1;
480 * The following bitfields are only for optimization purposes
481 * and hence races in setting them will not cause malfunction
484 /** Is fsync not implemented by fs? */
487 /** Is fsyncdir not implemented by fs? */
488 unsigned no_fsyncdir
:1;
490 /** Is flush not implemented by fs? */
493 /** Is setxattr not implemented by fs? */
494 unsigned no_setxattr
:1;
496 /** Is getxattr not implemented by fs? */
497 unsigned no_getxattr
:1;
499 /** Is listxattr not implemented by fs? */
500 unsigned no_listxattr
:1;
502 /** Is removexattr not implemented by fs? */
503 unsigned no_removexattr
:1;
505 /** Are posix file locking primitives not implemented by fs? */
508 /** Is access not implemented by fs? */
509 unsigned no_access
:1;
511 /** Is create not implemented by fs? */
512 unsigned no_create
:1;
514 /** Is interrupt not implemented by fs? */
515 unsigned no_interrupt
:1;
517 /** Is bmap not implemented by fs? */
520 /** Is poll not implemented by fs? */
523 /** Do multi-page cached writes */
524 unsigned big_writes
:1;
526 /** Don't apply umask to creation modes */
527 unsigned dont_mask
:1;
529 /** Are BSD file locking primitives not implemented by fs? */
532 /** Is fallocate not implemented by fs? */
533 unsigned no_fallocate
:1;
535 /** Use enhanced/automatic page cache invalidation. */
536 unsigned auto_inval_data
:1;
538 /** Does the filesystem support readdirplus? */
539 unsigned do_readdirplus
:1;
541 /** Does the filesystem want adaptive readdirplus? */
542 unsigned readdirplus_auto
:1;
544 /** Does the filesystem support asynchronous direct-IO submission? */
545 unsigned async_dio
:1;
547 /** The number of requests waiting for completion */
548 atomic_t num_waiting
;
550 /** Negotiated minor version */
553 /** Backing dev info */
554 struct backing_dev_info bdi
;
556 /** Entry on the fuse_conn_list */
557 struct list_head entry
;
559 /** Device ID from super block */
562 /** Dentries in the control filesystem */
563 struct dentry
*ctl_dentry
[FUSE_CTL_NUM_DENTRIES
];
565 /** number of dentries used in the above array */
568 /** O_ASYNC requests */
569 struct fasync_struct
*fasync
;
571 /** Key for lock owner ID scrambling */
574 /** Reserved request for the DESTROY message */
575 struct fuse_req
*destroy_req
;
577 /** Version counter for attribute changes */
580 /** Called on final put */
581 void (*release
)(struct fuse_conn
*);
583 /** Super block for this connection. */
584 struct super_block
*sb
;
586 /** Read/write semaphore to hold when accessing sb. */
587 struct rw_semaphore killsb
;
590 static inline struct fuse_conn
*get_fuse_conn_super(struct super_block
*sb
)
592 return sb
->s_fs_info
;
595 static inline struct fuse_conn
*get_fuse_conn(struct inode
*inode
)
597 return get_fuse_conn_super(inode
->i_sb
);
600 static inline struct fuse_inode
*get_fuse_inode(struct inode
*inode
)
602 return container_of(inode
, struct fuse_inode
, inode
);
605 static inline u64
get_node_id(struct inode
*inode
)
607 return get_fuse_inode(inode
)->nodeid
;
610 /** Device operations */
611 extern const struct file_operations fuse_dev_operations
;
613 extern const struct dentry_operations fuse_dentry_operations
;
616 * Inode to nodeid comparison.
618 int fuse_inode_eq(struct inode
*inode
, void *_nodeidp
);
621 * Get a filled in inode
623 struct inode
*fuse_iget(struct super_block
*sb
, u64 nodeid
,
624 int generation
, struct fuse_attr
*attr
,
625 u64 attr_valid
, u64 attr_version
);
627 int fuse_lookup_name(struct super_block
*sb
, u64 nodeid
, struct qstr
*name
,
628 struct fuse_entry_out
*outarg
, struct inode
**inode
);
631 * Send FORGET command
633 void fuse_queue_forget(struct fuse_conn
*fc
, struct fuse_forget_link
*forget
,
634 u64 nodeid
, u64 nlookup
);
636 struct fuse_forget_link
*fuse_alloc_forget(void);
638 /* Used by READDIRPLUS */
639 void fuse_force_forget(struct file
*file
, u64 nodeid
);
642 * Initialize READ or READDIR request
644 void fuse_read_fill(struct fuse_req
*req
, struct file
*file
,
645 loff_t pos
, size_t count
, int opcode
);
648 * Send OPEN or OPENDIR request
650 int fuse_open_common(struct inode
*inode
, struct file
*file
, bool isdir
);
652 struct fuse_file
*fuse_file_alloc(struct fuse_conn
*fc
);
653 struct fuse_file
*fuse_file_get(struct fuse_file
*ff
);
654 void fuse_file_free(struct fuse_file
*ff
);
655 void fuse_finish_open(struct inode
*inode
, struct file
*file
);
657 void fuse_sync_release(struct fuse_file
*ff
, int flags
);
660 * Send RELEASE or RELEASEDIR request
662 void fuse_release_common(struct file
*file
, int opcode
);
665 * Send FSYNC or FSYNCDIR request
667 int fuse_fsync_common(struct file
*file
, loff_t start
, loff_t end
,
668 int datasync
, int isdir
);
673 int fuse_notify_poll_wakeup(struct fuse_conn
*fc
,
674 struct fuse_notify_poll_wakeup_out
*outarg
);
677 * Initialize file operations on a regular file
679 void fuse_init_file_inode(struct inode
*inode
);
682 * Initialize inode operations on regular files and special files
684 void fuse_init_common(struct inode
*inode
);
687 * Initialize inode and file operations on a directory
689 void fuse_init_dir(struct inode
*inode
);
692 * Initialize inode operations on a symlink
694 void fuse_init_symlink(struct inode
*inode
);
697 * Change attributes of an inode
699 void fuse_change_attributes(struct inode
*inode
, struct fuse_attr
*attr
,
700 u64 attr_valid
, u64 attr_version
);
702 void fuse_change_attributes_common(struct inode
*inode
, struct fuse_attr
*attr
,
706 * Initialize the client device
708 int fuse_dev_init(void);
711 * Cleanup the client device
713 void fuse_dev_cleanup(void);
715 int fuse_ctl_init(void);
716 void fuse_ctl_cleanup(void);
721 struct fuse_req
*fuse_request_alloc(unsigned npages
);
723 struct fuse_req
*fuse_request_alloc_nofs(unsigned npages
);
728 void fuse_request_free(struct fuse_req
*req
);
731 * Get a request, may fail with -ENOMEM,
732 * caller should specify # elements in req->pages[] explicitly
734 struct fuse_req
*fuse_get_req(struct fuse_conn
*fc
, unsigned npages
);
735 struct fuse_req
*fuse_get_req_for_background(struct fuse_conn
*fc
,
739 * Increment reference count on request
741 void __fuse_get_request(struct fuse_req
*req
);
744 * Get a request, may fail with -ENOMEM,
745 * useful for callers who doesn't use req->pages[]
747 static inline struct fuse_req
*fuse_get_req_nopages(struct fuse_conn
*fc
)
749 return fuse_get_req(fc
, 0);
753 * Gets a requests for a file operation, always succeeds
755 struct fuse_req
*fuse_get_req_nofail_nopages(struct fuse_conn
*fc
,
759 * Decrement reference count of a request. If count goes to zero free
762 void fuse_put_request(struct fuse_conn
*fc
, struct fuse_req
*req
);
765 * Send a request (synchronous)
767 void fuse_request_send(struct fuse_conn
*fc
, struct fuse_req
*req
);
770 * Send a request in the background
772 void fuse_request_send_background(struct fuse_conn
*fc
, struct fuse_req
*req
);
774 void fuse_request_send_background_locked(struct fuse_conn
*fc
,
775 struct fuse_req
*req
);
777 /* Abort all requests */
778 void fuse_abort_conn(struct fuse_conn
*fc
);
781 * Invalidate inode attributes
783 void fuse_invalidate_attr(struct inode
*inode
);
785 void fuse_invalidate_entry_cache(struct dentry
*entry
);
788 * Acquire reference to fuse_conn
790 struct fuse_conn
*fuse_conn_get(struct fuse_conn
*fc
);
792 void fuse_conn_kill(struct fuse_conn
*fc
);
795 * Initialize fuse_conn
797 void fuse_conn_init(struct fuse_conn
*fc
);
800 * Release reference to fuse_conn
802 void fuse_conn_put(struct fuse_conn
*fc
);
805 * Add connection to control filesystem
807 int fuse_ctl_add_conn(struct fuse_conn
*fc
);
810 * Remove connection from control filesystem
812 void fuse_ctl_remove_conn(struct fuse_conn
*fc
);
815 * Is file type valid?
817 int fuse_valid_type(int m
);
820 * Is current process allowed to perform filesystem operation?
822 int fuse_allow_current_process(struct fuse_conn
*fc
);
824 u64
fuse_lock_owner_id(struct fuse_conn
*fc
, fl_owner_t id
);
826 int fuse_update_attributes(struct inode
*inode
, struct kstat
*stat
,
827 struct file
*file
, bool *refreshed
);
829 void fuse_flush_writepages(struct inode
*inode
);
831 void fuse_set_nowrite(struct inode
*inode
);
832 void fuse_release_nowrite(struct inode
*inode
);
834 u64
fuse_get_attr_version(struct fuse_conn
*fc
);
837 * File-system tells the kernel to invalidate cache for the given node id.
839 int fuse_reverse_inval_inode(struct super_block
*sb
, u64 nodeid
,
840 loff_t offset
, loff_t len
);
843 * File-system tells the kernel to invalidate parent attributes and
844 * the dentry matching parent/name.
846 * If the child_nodeid is non-zero and:
847 * - matches the inode number for the dentry matching parent/name,
848 * - is not a mount point
849 * - is a file or oan empty directory
850 * then the dentry is unhashed (d_delete()).
852 int fuse_reverse_inval_entry(struct super_block
*sb
, u64 parent_nodeid
,
853 u64 child_nodeid
, struct qstr
*name
);
855 int fuse_do_open(struct fuse_conn
*fc
, u64 nodeid
, struct file
*file
,
857 ssize_t
fuse_direct_io(struct fuse_io_priv
*io
, const struct iovec
*iov
,
858 unsigned long nr_segs
, size_t count
, loff_t
*ppos
,
860 long fuse_do_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
,
862 long fuse_ioctl_common(struct file
*file
, unsigned int cmd
,
863 unsigned long arg
, unsigned int flags
);
864 unsigned fuse_file_poll(struct file
*file
, poll_table
*wait
);
865 int fuse_dev_release(struct inode
*inode
, struct file
*file
);
867 void fuse_write_update_size(struct inode
*inode
, loff_t pos
);
869 int fuse_do_setattr(struct inode
*inode
, struct iattr
*attr
,
872 #endif /* _FS_FUSE_I_H */