fuse_i.h

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2006  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(2,6,9)
#error Kernel versions earlier than 2.6.9 are not supported
#endif

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,10)
#  define KERNEL_2_6_10_PLUS
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,11)
#  define KERNEL_2_6_11_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
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
#  define KERNEL_2_6_16_PLUS
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,17)
#  define KERNEL_2_6_17_PLUS
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,18)
#  define KERNEL_2_6_18_PLUS
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,19)
#  define KERNEL_2_6_19_PLUS
#endif

#if defined(__arm__) && LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
#define DCACHE_BUG
#endif

#include "config.h"
#endif /* FUSE_MAINLINE */
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
#ifdef HAVE_MUTEX_H
#include <linux/mutex.h>
#else
#include <asm/semaphore.h>
#define DEFINE_MUTEX(m) DECLARE_MUTEX(m)
#define mutex_init(m) init_MUTEX(m)
#define mutex_destroy(m) do { } while (0)
#define mutex_lock(m) down(m)
#define mutex_unlock(m) up(m)
#define mutex semaphore
#endif
#ifndef HAVE_I_MUTEX
#define i_mutex i_sem   /* Hack for struct inode */
#endif
#ifndef KERNEL_2_6_19_PLUS
#define clear_nlink(inode) (inode)->i_nlink = 0
#define inc_nlink(inode) (inode)->i_nlink++
#endif
#ifndef HAVE_CONFIG_BLOCK
#define CONFIG_BLOCK
#endif

/** Max number of pages that can be used in a single read request */
#define FUSE_MAX_PAGES_PER_REQ 32

/** Maximum number of outstanding background requests */
#define FUSE_MAX_BACKGROUND 10

/** It could be as large as PATH_MAX, but would that have any uses? */
#define FUSE_NAME_MAX 1024

/** Number of dentries for each connection in the control filesystem */
#define FUSE_CTL_NUM_DENTRIES 3

/** 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)

/** List of active connections */
extern struct list_head fuse_conn_list;

/** Global mutex protecting fuse_conn_list and the control filesystem */
extern struct mutex fuse_mutex;

/** FUSE inode */
00108 struct fuse_inode {
      /** Inode data */
00110       struct inode inode;

      /** Unique ID, which identifies the inode between userspace
       * and kernel */
00114       u64 nodeid;

      /** Number of lookups on this inode */
00117       u64 nlookup;

      /** The request used for sending the FORGET message */
00120       struct fuse_req *forget_req;

      /** Time in jiffies until the file attributes are valid */
00123       u64 i_time;
};

/** FUSE specific file data */
00127 struct fuse_file {
      /** Request reserved for flush and release */
00129       struct fuse_req *reserved_req;

      /** File handle used by userspace */
00132       u64 fh;
};

/** One input argument of a request */
00136 struct fuse_in_arg {
      unsigned size;
      const void *value;
};

/** The request input */
00142 struct fuse_in {
      /** The request header */
00144       struct fuse_in_header h;

      /** True if the data for the last argument is in req->pages */
00147       unsigned argpages:1;

      /** Number of arguments */
00150       unsigned numargs;

      /** Array of arguments */
00153       struct fuse_in_arg args[3];
};

/** One output argument of a request */
00157 struct fuse_arg {
      unsigned size;
      void *value;
};

/** The request output */
00163 struct fuse_out {
      /** Header returned from userspace */
00165       struct fuse_out_header h;

      /*
       * The following bitfields are not changed during the request
       * processing
       */

      /** Last argument is variable length (can be shorter than
          arg->size) */
00174       unsigned argvar:1;

      /** Last argument is a list of pages to copy data to */
00177       unsigned argpages:1;

      /** Zero partially or not copied pages */
00180       unsigned page_zeroing:1;

      /** Number or arguments */
00183       unsigned numargs;

      /** Array of arguments */
00186       struct fuse_arg args[3];
};

/** The request state */
enum fuse_req_state {
      FUSE_REQ_INIT = 0,
      FUSE_REQ_PENDING,
      FUSE_REQ_READING,
      FUSE_REQ_SENT,
      FUSE_REQ_WRITING,
      FUSE_REQ_FINISHED
};

struct fuse_conn;

/**
 * A request to the client
 */
00204 struct fuse_req {
      /** This can be on either pending processing or io lists in
          fuse_conn */
00207       struct list_head list;

      /** Entry on the interrupts list  */
00210       struct list_head intr_entry;

      /** refcount */
00213       atomic_t count;

      /** Unique ID for the interrupt request */
00216       u64 intr_unique;

      /*
       * The following bitfields are either set once before the
       * request is queued or setting/clearing them is protected by
       * fuse_conn->lock
       */

      /** True if the request has reply */
00225       unsigned isreply:1;

      /** Force sending of the request even if interrupted */
00228       unsigned force:1;

      /** The request was aborted */
00231       unsigned aborted:1;

      /** Request is sent in the background */
00234       unsigned background:1;

      /** The request has been interrupted */
00237       unsigned interrupted:1;

      /** Data is being copied to/from the request */
00240       unsigned locked:1;

      /** Request is counted as "waiting" */
00243       unsigned waiting:1;

      /** State of the request */
00246       enum fuse_req_state state;

      /** The request input */
00249       struct fuse_in in;

      /** The request output */
00252       struct fuse_out out;

      /** Used to wake up the task waiting for completion of request*/
00255       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 init_in;
            struct fuse_init_out init_out;
            struct fuse_read_in read_in;
            struct fuse_lk_in lk_in;
      } misc;

      /** page vector */
00268       struct page *pages[FUSE_MAX_PAGES_PER_REQ];

      /** number of pages in vector */
00271       unsigned num_pages;

      /** offset of data on first page */
00274       unsigned page_offset;

      /** File used in the request (or NULL) */
00277       struct file *file;

      /** vfsmount used in release */
00280       struct vfsmount *vfsmount;

      /** dentry used in release */
00283       struct dentry *dentry;

      /** Request completion callback */
      void (*end)(struct fuse_conn *, struct fuse_req *);

      /** Request is stolen from fuse_file->reserved_req */
00289       struct file *stolen_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.
 */
00299 struct fuse_conn {
      /** Lock protecting accessess to  members of this structure */
00301       spinlock_t lock;

      /** Mutex protecting against directory alias creation */
00304       struct mutex inst_mutex;

      /** Refcount */
00307       atomic_t count;

      /** The user id for this mount */
00310       uid_t user_id;

      /** The group id for this mount */
00313       gid_t group_id;

      /** The fuse mount flags for this mount */
00316       unsigned flags;

      /** Maximum read size */
00319       unsigned max_read;

      /** Maximum write size */
00322       unsigned max_write;

      /** Readers of the connection are waiting on this */
00325       wait_queue_head_t waitq;

      /** The list of pending requests */
00328       struct list_head pending;

      /** The list of requests being processed */
00331       struct list_head processing;

      /** The list of requests under I/O */
00334       struct list_head io;

      /** Number of requests currently in the background */
00337       unsigned num_background;

      /** Pending interrupts */
00340       struct list_head interrupts;

      /** Flag indicating if connection is blocked.  This will be
          the case before the INIT reply is received, and if there
          are too many outstading backgrounds requests */
00345       int blocked;

      /** waitq for blocked connection */
00348       wait_queue_head_t blocked_waitq;

      /** The next unique request id */
00351       u64 reqctr;

      /** Connection established, cleared on umount, connection
          abort and device release */
00355       unsigned connected;

      /** Connection failed (version mismatch).  Cannot race with
          setting other bitfields since it is only set once in INIT
          reply, before any other request, and never cleared */
00360       unsigned conn_error : 1;

      /** Connection successful.  Only set in INIT */
00363       unsigned conn_init : 1;

      /** Do readpages asynchronously?  Only set in INIT */
00366       unsigned async_read : 1;

      /*
       * The following bitfields are only for optimization purposes
       * and hence races in setting them will not cause malfunction
       */

      /** Is fsync not implemented by fs? */
00374       unsigned no_fsync : 1;

      /** Is fsyncdir not implemented by fs? */
00377       unsigned no_fsyncdir : 1;

      /** Is flush not implemented by fs? */
00380       unsigned no_flush : 1;

      /** Is setxattr not implemented by fs? */
00383       unsigned no_setxattr : 1;

      /** Is getxattr not implemented by fs? */
00386       unsigned no_getxattr : 1;

      /** Is listxattr not implemented by fs? */
00389       unsigned no_listxattr : 1;

      /** Is removexattr not implemented by fs? */
00392       unsigned no_removexattr : 1;

      /** Are file locking primitives not implemented by fs? */
00395       unsigned no_lock : 1;

      /** Is access not implemented by fs? */
00398       unsigned no_access : 1;

      /** Is create not implemented by fs? */
00401       unsigned no_create : 1;

      /** Is interrupt not implemented by fs? */
00404       unsigned no_interrupt : 1;

      /** Is bmap not implemented by fs? */
00407       unsigned no_bmap : 1;

      /** The number of requests waiting for completion */
00410       atomic_t num_waiting;

      /** Negotiated minor version */
00413       unsigned minor;

      /** Backing dev info */
00416       struct backing_dev_info bdi;

      /** Entry on the fuse_conn_list */
00419       struct list_head entry;

      /** Unique ID */
00422       u64 id;

      /** Dentries in the control filesystem */
00425       struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];

      /** number of dentries used in the above array */
00428       int ctl_ndents;

      /** O_ASYNC requests */
00431       struct fasync_struct *fasync;

      /** Key for lock owner ID scrambling */
00434       u32 scramble_key[4];

      /** Reserved request for the DESTROY message */
00437       struct fuse_req *destroy_req;
};

static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
{
      return sb->s_fs_info;
}

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;

/**
 * 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);

/**
 * Initialize READ or READDIR request
 */
void fuse_read_fill(struct fuse_req *req, struct file *file,
                struct inode *inode, loff_t pos, size_t count, int opcode);

/**
 * Send OPEN or OPENDIR request
 */
int fuse_open_common(struct inode *inode, struct file *file, int isdir);

struct fuse_file *fuse_file_alloc(void);
void fuse_file_free(struct fuse_file *ff);
void fuse_finish_open(struct inode *inode, struct file *file,
                  struct fuse_file *ff, struct fuse_open_out *outarg);

/** */
struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
                           int opcode);
/**
 * 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);

/**
 * Initialize the client device
 */
int fuse_dev_init(void);

/**
 * Cleanup the client device
 */
void fuse_dev_cleanup(void);

int fuse_ctl_init(void);
void fuse_ctl_cleanup(void);

/**
 * Allocate a request
 */
struct fuse_req *fuse_request_alloc(void);

/**
 * Free a request
 */
void fuse_request_free(struct fuse_req *req);

/**
 * Get a request, may fail with -ENOMEM
 */
struct fuse_req *fuse_get_req(struct fuse_conn *fc);

/**
 * Gets a requests for a file operation, always succeeds
 */
struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);

/**
 * Decrement reference count of a request.  If count goes to zero free
 * the request.
 */
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);

/* Abort all requests */
void fuse_abort_conn(struct fuse_conn *fc);

/**
 * Get the attributes of a file
 */
int fuse_do_getattr(struct inode *inode);

/**
 * Invalidate inode attributes
 */
void fuse_invalidate_attr(struct inode *inode);

/**
 * Acquire reference to fuse_conn
 */
struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);

/**
 * Release reference to fuse_conn
 */
void fuse_conn_put(struct fuse_conn *fc);

/**
 * Add connection to control filesystem
 */
int fuse_ctl_add_conn(struct fuse_conn *fc);

/**
 * Remove connection from control filesystem
 */
void fuse_ctl_remove_conn(struct fuse_conn *fc);