[PATCH] FUSE - device functions
This adds the FUSE device handling functions.
This contains the following files:
o dev.c
- fuse device operations (read, write, release, poll)
- registers misc device
- support for sending requests to userspace
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index eed6e89..50ad6a0 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -15,6 +15,12 @@
#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
+
/** FUSE inode */
struct fuse_inode {
/** Inode data */
@@ -28,6 +34,123 @@
unsigned long i_time;
};
+/** 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;
+
+ /** 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_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.
*
@@ -39,9 +162,37 @@
/** The superblock of the mounted filesystem */
struct super_block *sb;
+ /** The opened client device */
+ struct file *file;
+
/** The user id for this mount */
uid_t user_id;
+ /** 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;
+
+ /** 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;
+
+ /** The list of unused requests */
+ struct list_head unused_list;
+
+ /** The next unique request id */
+ u64 reqctr;
+
+ /** Connection failed (version mismatch) */
+ unsigned conn_error : 1;
+
/** Backing dev info */
struct backing_dev_info bdi;
};
@@ -71,13 +222,20 @@
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
+ * - 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;
@@ -87,3 +245,68 @@
*/
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);
+
+/**
+ * Send the INIT message
+ */
+void fuse_send_init(struct fuse_conn *fc);