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fuse_i.h

/*
  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.
*/

#ifdef FUSE_MAINLINE
#include <linux/fuse.h>
#else
#include "fuse_kernel.h"
#include <linux/version.h>
#include <linux/utsname.h>

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) && LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
#error Kernel version 2.5.* not supported
#endif

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
#  define KERNEL_2_6
#  if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,6)
#    define KERNEL_2_6_6_PLUS
#  endif
#  if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,8)
#    define KERNEL_2_6_8_PLUS
#  endif
#  if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,9)
#    define KERNEL_2_6_9_PLUS
#  endif
#  if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
#    define KERNEL_2_6_10_PLUS
#  endif
#  if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,12)
#    define KERNEL_2_6_12_PLUS
#  endif
#  if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,13)
#    define KERNEL_2_6_13_PLUS
#  endif
#endif

#include "config.h"
#ifndef KERNEL_2_6
#  include <linux/config.h>
#  ifdef CONFIG_MODVERSIONS
#     define MODVERSIONS
#     include <linux/modversions.h>
#  endif
#  ifndef HAVE_I_SIZE_FUNC
#     define i_size_read(inode) ((inode)->i_size)
#     define i_size_write(inode, size) do { (inode)->i_size = size; } while(0)
#  endif
#  define new_decode_dev(x) (x)
#  define new_encode_dev(x) (x)
#endif /* KERNEL_2_6 */
#endif /* FUSE_MAINLINE */
#include <linux/fs.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#ifdef KERNEL_2_6
#include <linux/mm.h>
#include <linux/backing-dev.h>
#endif
#include <asm/semaphore.h>

#ifndef BUG_ON
#define BUG_ON(x)
#endif
#ifndef container_of
#define container_of(ptr, type, member) ({                  \
        const typeof( ((type *)0)->member ) *__mptr = (ptr);      \
        (type *)( (char *)__mptr - offsetof(type,member) );})
#endif
#ifndef __user
#define __user
#endif
#ifndef KERNEL_2_6
#include <linux/pagemap.h>
static inline void set_page_dirty_lock(struct page *page)
{
      lock_page(page);
      set_page_dirty(page);
      unlock_page(page);
}
#endif
/** 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)

#ifndef KERNEL_2_6
/** Allow FUSE to combine reads into 64k chunks.  This is useful if
    the filesystem is better at handling large chunks */
#define FUSE_LARGE_READ          (1 << 31)
#endif

/** FUSE inode */
00109 struct fuse_inode {
      /** Inode data */
00111       struct inode inode;

      /** Unique ID, which identifies the inode between userspace
       * and kernel */
00115       u64 nodeid;

      /** Number of lookups on this inode */
00118       u64 nlookup;

      /** The request used for sending the FORGET message */
00121       struct fuse_req *forget_req;

      /** Time in jiffies until the file attributes are valid */
00124       unsigned long i_time;
};

/** FUSE specific file data */
00128 struct fuse_file {
      /** Request reserved for flush and release */
00130       struct fuse_req *release_req;

      /** File handle used by userspace */
00133       u64 fh;
};

/** One input argument of a request */
00137 struct fuse_in_arg {
      unsigned size;
      const void *value;
};

/** The request input */
00143 struct fuse_in {
      /** The request header */
00145       struct fuse_in_header h;

      /** True if the data for the last argument is in req->pages */
00148       unsigned argpages:1;

      /** Number of arguments */
00151       unsigned numargs;

      /** Array of arguments */
00154       struct fuse_in_arg args[3];
};

/** One output argument of a request */
00158 struct fuse_arg {
      unsigned size;
      void *value;
};

/** The request output */
00164 struct fuse_out {
      /** Header returned from userspace */
00166       struct fuse_out_header h;

      /** Last argument is variable length (can be shorter than
          arg->size) */
00170       unsigned argvar:1;

      /** Last argument is a list of pages to copy data to */
00173       unsigned argpages:1;

      /** Zero partially or not copied pages */
00176       unsigned page_zeroing:1;

      /** Number or arguments */
00179       unsigned numargs;

      /** Array of arguments */
00182       struct fuse_arg args[3];
};

struct fuse_req;
struct fuse_conn;

/**
 * A request to the client
 */
00191 struct fuse_req {
      /** This can be on either unused_list, pending or processing
          lists in fuse_conn */
00194       struct list_head list;

      /** Entry on the background list */
00197       struct list_head bg_entry;

      /** refcount */
00200       atomic_t count;

      /** True if the request has reply */
00203       unsigned isreply:1;

      /** The request is preallocated */
00206       unsigned preallocated:1;

      /** The request was interrupted */
00209       unsigned interrupted:1;

      /** Request is sent in the background */
00212       unsigned background:1;

      /** Data is being copied to/from the request */
00215       unsigned locked:1;

      /** Request has been sent to userspace */
00218       unsigned sent:1;

      /** The request is finished */
00221       unsigned finished:1;

      /** The request input */
00224       struct fuse_in in;

      /** The request output */
00227       struct fuse_out out;

      /** Used to wake up the task waiting for completion of request*/
00230       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 */
00240       struct page *pages[FUSE_MAX_PAGES_PER_REQ];

      /** number of pages in vector */
00243       unsigned num_pages;

      /** offset of data on first page */
00246       unsigned page_offset;

      /** Inode used in the request */
00249       struct inode *inode;

      /** Second inode used in the request (or NULL) */
00252       struct inode *inode2;

      /** File used in the request (or NULL) */
00255       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.
 */
00265 struct fuse_conn {
      /** Reference count */
00267       int count;

      /** The user id for this mount */
00270       uid_t user_id;

      /** The group id for this mount */
00273       gid_t group_id;

      /** The fuse mount flags for this mount */
00276       unsigned flags;

      /** Maximum read size */
00279       unsigned max_read;

      /** Maximum write size */
00282       unsigned max_write;

      /** Readers of the connection are waiting on this */
00285       wait_queue_head_t waitq;

      /** The list of pending requests */
00288       struct list_head pending;

      /** The list of requests being processed */
00291       struct list_head processing;

      /** Requests put in the background (RELEASE or any other
          interrupted request) */
00295       struct list_head background;

      /** Controls the maximum number of outstanding requests */
00298       struct semaphore outstanding_sem;

      /** This counts the number of outstanding requests if
          outstanding_sem would go negative */
00302       unsigned outstanding_debt;

      /** RW semaphore for exclusion with fuse_put_super() */
00305       struct rw_semaphore sbput_sem;

      /** The list of unused requests */
00308       struct list_head unused_list;

      /** The next unique request id */
00311       u64 reqctr;

      /** Mount is active */
00314       unsigned mounted : 1;

      /** Connection established */
00317       unsigned connected : 1;

      /** Connection failed (version mismatch) */
00320       unsigned conn_error : 1;

      /** Is fsync not implemented by fs? */
00323       unsigned no_fsync : 1;

      /** Is fsyncdir not implemented by fs? */
00326       unsigned no_fsyncdir : 1;

      /** Is flush not implemented by fs? */
00329       unsigned no_flush : 1;

      /** Is setxattr not implemented by fs? */
00332       unsigned no_setxattr : 1;

      /** Is getxattr not implemented by fs? */
00335       unsigned no_getxattr : 1;

      /** Is listxattr not implemented by fs? */
00338       unsigned no_listxattr : 1;

      /** Is removexattr not implemented by fs? */
00341       unsigned no_removexattr : 1;

#ifdef KERNEL_2_6
      /** Backing dev info */
00345       struct backing_dev_info bdi;
#endif
};

static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb)
{
#ifdef KERNEL_2_6
      return (struct fuse_conn **) &sb->s_fs_info;
#else
      return (struct fuse_conn **) &sb->u.generic_sbp;
#endif
}

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);

/**
 * Initialize file operations on a regular file
 */
void fuse_init_file_inode(struct inode *inode);

/**
 * Initialize inode operations on regular files and special files
 */
void fuse_init_common(struct inode *inode);

/**
 * Initialize inode and file operations on a directory
 */
void fuse_init_dir(struct inode *inode);

/**
 * Initialize 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);

/**
 * Decrement reference count of a request.  If count goes to zero put
 * on unused list (preallocated) or free request (not preallocated).
 */
void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);

/**
 * Send a request (synchronous)
 */
void request_send(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 associated 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);

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