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
{
232 * A request to the client
235 /** This can be on either pending processing or io lists in
237 struct list_head list
;
239 /** Entry on the interrupts list */
240 struct list_head intr_entry
;
245 /** Unique ID for the interrupt request */
249 * The following bitfields are either set once before the
250 * request is queued or setting/clearing them is protected by
254 /** True if the request has reply */
257 /** Force sending of the request even if interrupted */
260 /** The request was aborted */
263 /** Request is sent in the background */
264 unsigned background
:1;
266 /** The request has been interrupted */
267 unsigned interrupted
:1;
269 /** Data is being copied to/from the request */
272 /** Request is counted as "waiting" */
275 /** State of the request */
276 enum fuse_req_state state
;
278 /** The request input */
281 /** The request output */
284 /** Used to wake up the task waiting for completion of request*/
285 wait_queue_head_t waitq
;
287 /** Data for asynchronous requests */
291 struct fuse_release_in in
;
292 struct work_struct work
;
296 struct fuse_init_in init_in
;
297 struct fuse_init_out init_out
;
298 struct cuse_init_in cuse_init_in
;
300 struct fuse_read_in in
;
304 struct fuse_write_in in
;
305 struct fuse_write_out out
;
307 struct fuse_notify_retrieve_in retrieve_in
;
308 struct fuse_lk_in lk_in
;
314 /** page-descriptor vector */
315 struct fuse_page_desc
*page_descs
;
317 /** size of the 'pages' array */
320 /** inline page vector */
321 struct page
*inline_pages
[FUSE_REQ_INLINE_PAGES
];
323 /** inline page-descriptor vector */
324 struct fuse_page_desc inline_page_descs
[FUSE_REQ_INLINE_PAGES
];
326 /** number of pages in vector */
329 /** File used in the request (or NULL) */
330 struct fuse_file
*ff
;
332 /** Inode used in the request or NULL */
335 /** Link on fi->writepages */
336 struct list_head writepages_entry
;
338 /** Request completion callback */
339 void (*end
)(struct fuse_conn
*, struct fuse_req
*);
341 /** Request is stolen from fuse_file->reserved_req */
342 struct file
*stolen_file
;
348 * This structure is created, when the filesystem is mounted, and is
349 * destroyed, when the client device is closed and the filesystem is
353 /** Lock protecting accessess to members of this structure */
356 /** Mutex protecting against directory alias creation */
357 struct mutex inst_mutex
;
362 /** The user id for this mount */
365 /** The group id for this mount */
368 /** The fuse mount flags for this mount */
371 /** Maximum read size */
374 /** Maximum write size */
377 /** Readers of the connection are waiting on this */
378 wait_queue_head_t waitq
;
380 /** The list of pending requests */
381 struct list_head pending
;
383 /** The list of requests being processed */
384 struct list_head processing
;
386 /** The list of requests under I/O */
389 /** The next unique kernel file handle */
392 /** rbtree of fuse_files waiting for poll events indexed by ph */
393 struct rb_root polled_files
;
395 /** Maximum number of outstanding background requests */
396 unsigned max_background
;
398 /** Number of background requests at which congestion starts */
399 unsigned congestion_threshold
;
401 /** Number of requests currently in the background */
402 unsigned num_background
;
404 /** Number of background requests currently queued for userspace */
405 unsigned active_background
;
407 /** The list of background requests set aside for later queuing */
408 struct list_head bg_queue
;
410 /** Pending interrupts */
411 struct list_head interrupts
;
413 /** Queue of pending forgets */
414 struct fuse_forget_link forget_list_head
;
415 struct fuse_forget_link
*forget_list_tail
;
417 /** Batching of FORGET requests (positive indicates FORGET batch) */
420 /** Flag indicating if connection is blocked. This will be
421 the case before the INIT reply is received, and if there
422 are too many outstading backgrounds requests */
425 /** waitq for blocked connection */
426 wait_queue_head_t blocked_waitq
;
428 /** waitq for reserved requests */
429 wait_queue_head_t reserved_req_waitq
;
431 /** The next unique request id */
434 /** Connection established, cleared on umount, connection
435 abort and device release */
438 /** Connection failed (version mismatch). Cannot race with
439 setting other bitfields since it is only set once in INIT
440 reply, before any other request, and never cleared */
441 unsigned conn_error
:1;
443 /** Connection successful. Only set in INIT */
444 unsigned conn_init
:1;
446 /** Do readpages asynchronously? Only set in INIT */
447 unsigned async_read
:1;
449 /** Do not send separate SETATTR request before open(O_TRUNC) */
450 unsigned atomic_o_trunc
:1;
452 /** Filesystem supports NFS exporting. Only set in INIT */
453 unsigned export_support
:1;
455 /** Set if bdi is valid */
456 unsigned bdi_initialized
:1;
459 * The following bitfields are only for optimization purposes
460 * and hence races in setting them will not cause malfunction
463 /** Is fsync not implemented by fs? */
466 /** Is fsyncdir not implemented by fs? */
467 unsigned no_fsyncdir
:1;
469 /** Is flush not implemented by fs? */
472 /** Is setxattr not implemented by fs? */
473 unsigned no_setxattr
:1;
475 /** Is getxattr not implemented by fs? */
476 unsigned no_getxattr
:1;
478 /** Is listxattr not implemented by fs? */
479 unsigned no_listxattr
:1;
481 /** Is removexattr not implemented by fs? */
482 unsigned no_removexattr
:1;
484 /** Are posix file locking primitives not implemented by fs? */
487 /** Is access not implemented by fs? */
488 unsigned no_access
:1;
490 /** Is create not implemented by fs? */
491 unsigned no_create
:1;
493 /** Is interrupt not implemented by fs? */
494 unsigned no_interrupt
:1;
496 /** Is bmap not implemented by fs? */
499 /** Is poll not implemented by fs? */
502 /** Do multi-page cached writes */
503 unsigned big_writes
:1;
505 /** Don't apply umask to creation modes */
506 unsigned dont_mask
:1;
508 /** Are BSD file locking primitives not implemented by fs? */
511 /** Is fallocate not implemented by fs? */
512 unsigned no_fallocate
:1;
514 /** Use enhanced/automatic page cache invalidation. */
515 unsigned auto_inval_data
:1;
517 /** Does the filesystem support readdirplus? */
518 unsigned do_readdirplus
:1;
520 /** Does the filesystem want adaptive readdirplus? */
521 unsigned readdirplus_auto
:1;
523 /** The number of requests waiting for completion */
524 atomic_t num_waiting
;
526 /** Negotiated minor version */
529 /** Backing dev info */
530 struct backing_dev_info bdi
;
532 /** Entry on the fuse_conn_list */
533 struct list_head entry
;
535 /** Device ID from super block */
538 /** Dentries in the control filesystem */
539 struct dentry
*ctl_dentry
[FUSE_CTL_NUM_DENTRIES
];
541 /** number of dentries used in the above array */
544 /** O_ASYNC requests */
545 struct fasync_struct
*fasync
;
547 /** Key for lock owner ID scrambling */
550 /** Reserved request for the DESTROY message */
551 struct fuse_req
*destroy_req
;
553 /** Version counter for attribute changes */
556 /** Called on final put */
557 void (*release
)(struct fuse_conn
*);
559 /** Super block for this connection. */
560 struct super_block
*sb
;
562 /** Read/write semaphore to hold when accessing sb. */
563 struct rw_semaphore killsb
;
566 static inline struct fuse_conn
*get_fuse_conn_super(struct super_block
*sb
)
568 return sb
->s_fs_info
;
571 static inline struct fuse_conn
*get_fuse_conn(struct inode
*inode
)
573 return get_fuse_conn_super(inode
->i_sb
);
576 static inline struct fuse_inode
*get_fuse_inode(struct inode
*inode
)
578 return container_of(inode
, struct fuse_inode
, inode
);
581 static inline u64
get_node_id(struct inode
*inode
)
583 return get_fuse_inode(inode
)->nodeid
;
586 /** Device operations */
587 extern const struct file_operations fuse_dev_operations
;
589 extern const struct dentry_operations fuse_dentry_operations
;
592 * Inode to nodeid comparison.
594 int fuse_inode_eq(struct inode
*inode
, void *_nodeidp
);
597 * Get a filled in inode
599 struct inode
*fuse_iget(struct super_block
*sb
, u64 nodeid
,
600 int generation
, struct fuse_attr
*attr
,
601 u64 attr_valid
, u64 attr_version
);
603 int fuse_lookup_name(struct super_block
*sb
, u64 nodeid
, struct qstr
*name
,
604 struct fuse_entry_out
*outarg
, struct inode
**inode
);
607 * Send FORGET command
609 void fuse_queue_forget(struct fuse_conn
*fc
, struct fuse_forget_link
*forget
,
610 u64 nodeid
, u64 nlookup
);
612 struct fuse_forget_link
*fuse_alloc_forget(void);
614 /* Used by READDIRPLUS */
615 void fuse_force_forget(struct file
*file
, u64 nodeid
);
618 * Initialize READ or READDIR request
620 void fuse_read_fill(struct fuse_req
*req
, struct file
*file
,
621 loff_t pos
, size_t count
, int opcode
);
624 * Send OPEN or OPENDIR request
626 int fuse_open_common(struct inode
*inode
, struct file
*file
, bool isdir
);
628 struct fuse_file
*fuse_file_alloc(struct fuse_conn
*fc
);
629 struct fuse_file
*fuse_file_get(struct fuse_file
*ff
);
630 void fuse_file_free(struct fuse_file
*ff
);
631 void fuse_finish_open(struct inode
*inode
, struct file
*file
);
633 void fuse_sync_release(struct fuse_file
*ff
, int flags
);
636 * Send RELEASE or RELEASEDIR request
638 void fuse_release_common(struct file
*file
, int opcode
);
641 * Send FSYNC or FSYNCDIR request
643 int fuse_fsync_common(struct file
*file
, loff_t start
, loff_t end
,
644 int datasync
, int isdir
);
649 int fuse_notify_poll_wakeup(struct fuse_conn
*fc
,
650 struct fuse_notify_poll_wakeup_out
*outarg
);
653 * Initialize file operations on a regular file
655 void fuse_init_file_inode(struct inode
*inode
);
658 * Initialize inode operations on regular files and special files
660 void fuse_init_common(struct inode
*inode
);
663 * Initialize inode and file operations on a directory
665 void fuse_init_dir(struct inode
*inode
);
668 * Initialize inode operations on a symlink
670 void fuse_init_symlink(struct inode
*inode
);
673 * Change attributes of an inode
675 void fuse_change_attributes(struct inode
*inode
, struct fuse_attr
*attr
,
676 u64 attr_valid
, u64 attr_version
);
678 void fuse_change_attributes_common(struct inode
*inode
, struct fuse_attr
*attr
,
682 * Initialize the client device
684 int fuse_dev_init(void);
687 * Cleanup the client device
689 void fuse_dev_cleanup(void);
691 int fuse_ctl_init(void);
692 void fuse_ctl_cleanup(void);
697 struct fuse_req
*fuse_request_alloc(unsigned npages
);
699 struct fuse_req
*fuse_request_alloc_nofs(unsigned npages
);
704 void fuse_request_free(struct fuse_req
*req
);
707 * Get a request, may fail with -ENOMEM,
708 * caller should specify # elements in req->pages[] explicitly
710 struct fuse_req
*fuse_get_req(struct fuse_conn
*fc
, unsigned npages
);
713 * Get a request, may fail with -ENOMEM,
714 * useful for callers who doesn't use req->pages[]
716 static inline struct fuse_req
*fuse_get_req_nopages(struct fuse_conn
*fc
)
718 return fuse_get_req(fc
, 0);
722 * Gets a requests for a file operation, always succeeds
724 struct fuse_req
*fuse_get_req_nofail_nopages(struct fuse_conn
*fc
,
728 * Decrement reference count of a request. If count goes to zero free
731 void fuse_put_request(struct fuse_conn
*fc
, struct fuse_req
*req
);
734 * Send a request (synchronous)
736 void fuse_request_send(struct fuse_conn
*fc
, struct fuse_req
*req
);
739 * Send a request in the background
741 void fuse_request_send_background(struct fuse_conn
*fc
, struct fuse_req
*req
);
743 void fuse_request_send_background_locked(struct fuse_conn
*fc
,
744 struct fuse_req
*req
);
746 /* Abort all requests */
747 void fuse_abort_conn(struct fuse_conn
*fc
);
750 * Invalidate inode attributes
752 void fuse_invalidate_attr(struct inode
*inode
);
754 void fuse_invalidate_entry_cache(struct dentry
*entry
);
757 * Acquire reference to fuse_conn
759 struct fuse_conn
*fuse_conn_get(struct fuse_conn
*fc
);
761 void fuse_conn_kill(struct fuse_conn
*fc
);
764 * Initialize fuse_conn
766 void fuse_conn_init(struct fuse_conn
*fc
);
769 * Release reference to fuse_conn
771 void fuse_conn_put(struct fuse_conn
*fc
);
774 * Add connection to control filesystem
776 int fuse_ctl_add_conn(struct fuse_conn
*fc
);
779 * Remove connection from control filesystem
781 void fuse_ctl_remove_conn(struct fuse_conn
*fc
);
784 * Is file type valid?
786 int fuse_valid_type(int m
);
789 * Is current process allowed to perform filesystem operation?
791 int fuse_allow_current_process(struct fuse_conn
*fc
);
793 u64
fuse_lock_owner_id(struct fuse_conn
*fc
, fl_owner_t id
);
795 int fuse_update_attributes(struct inode
*inode
, struct kstat
*stat
,
796 struct file
*file
, bool *refreshed
);
798 void fuse_flush_writepages(struct inode
*inode
);
800 void fuse_set_nowrite(struct inode
*inode
);
801 void fuse_release_nowrite(struct inode
*inode
);
803 u64
fuse_get_attr_version(struct fuse_conn
*fc
);
806 * File-system tells the kernel to invalidate cache for the given node id.
808 int fuse_reverse_inval_inode(struct super_block
*sb
, u64 nodeid
,
809 loff_t offset
, loff_t len
);
812 * File-system tells the kernel to invalidate parent attributes and
813 * the dentry matching parent/name.
815 * If the child_nodeid is non-zero and:
816 * - matches the inode number for the dentry matching parent/name,
817 * - is not a mount point
818 * - is a file or oan empty directory
819 * then the dentry is unhashed (d_delete()).
821 int fuse_reverse_inval_entry(struct super_block
*sb
, u64 parent_nodeid
,
822 u64 child_nodeid
, struct qstr
*name
);
824 int fuse_do_open(struct fuse_conn
*fc
, u64 nodeid
, struct file
*file
,
826 ssize_t
fuse_direct_io(struct file
*file
, const struct iovec
*iov
,
827 unsigned long nr_segs
, size_t count
, loff_t
*ppos
,
829 long fuse_do_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
,
831 long fuse_ioctl_common(struct file
*file
, unsigned int cmd
,
832 unsigned long arg
, unsigned int flags
);
833 unsigned fuse_file_poll(struct file
*file
, poll_table
*wait
);
834 int fuse_dev_release(struct inode
*inode
, struct file
*file
);
836 void fuse_write_update_size(struct inode
*inode
, loff_t pos
);
838 #endif /* _FS_FUSE_I_H */