mergerfs/libfuse/lib/fuse_lowlevel.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU LGPLv2.
  See the file COPYING.LIB
*/

#define _GNU_SOURCE

#include "config.h"
#include "fuse_i.h"
#include "fuse_kernel.h"
#include "fuse_opt.h"
#include "fuse_misc.h"
#include "xmem.h"

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <errno.h>
#include <assert.h>
#include <sys/file.h>

#ifndef F_LINUX_SPECIFIC_BASE
#define F_LINUX_SPECIFIC_BASE       1024
#endif
#ifndef F_SETPIPE_SZ
#define F_SETPIPE_SZ	(F_LINUX_SPECIFIC_BASE + 7)
#endif


#define PARAM(inarg) (((char *)(inarg)) + sizeof(*(inarg)))
#define OFFSET_MAX 0x7fffffffffffffffLL

#define container_of(ptr, type, member) ({                      \
      const typeof( ((type *)0)->member ) *__mptr = (ptr);      \
      (type *)( (char *)__mptr - offsetof(type,member) );})

struct fuse_pollhandle {
  uint64_t kh;
  struct fuse_chan *ch;
  struct fuse_ll *f;
};

static size_t pagesize;

static __attribute__((constructor)) void fuse_ll_init_pagesize(void)
{
  pagesize = getpagesize();
}

static
void
convert_stat(const struct stat *stbuf_,
             struct fuse_attr  *attr_)
{
  attr_->ino       = stbuf_->st_ino;
  attr_->mode      = stbuf_->st_mode;
  attr_->nlink     = stbuf_->st_nlink;
  attr_->uid       = stbuf_->st_uid;
  attr_->gid       = stbuf_->st_gid;
  attr_->rdev      = stbuf_->st_rdev;
  attr_->size      = stbuf_->st_size;
  attr_->blksize   = stbuf_->st_blksize;
  attr_->blocks    = stbuf_->st_blocks;
  attr_->atime     = stbuf_->st_atime;
  attr_->mtime     = stbuf_->st_mtime;
  attr_->ctime     = stbuf_->st_ctime;
  attr_->atimensec = ST_ATIM_NSEC(stbuf_);
  attr_->mtimensec = ST_MTIM_NSEC(stbuf_);
  attr_->ctimensec = ST_CTIM_NSEC(stbuf_);
}

static
void
convert_attr(const struct fuse_setattr_in *attr_,
             struct stat                  *stbuf_)
{
  stbuf_->st_mode  = attr_->mode;
  stbuf_->st_uid   = attr_->uid;
  stbuf_->st_gid   = attr_->gid;
  stbuf_->st_size  = attr_->size;
  stbuf_->st_atime = attr_->atime;
  stbuf_->st_mtime = attr_->mtime;
  stbuf_->st_ctime = attr_->ctime;
  ST_ATIM_NSEC_SET(stbuf_,attr_->atimensec);
  ST_MTIM_NSEC_SET(stbuf_,attr_->mtimensec);
  ST_CTIM_NSEC_SET(stbuf_,attr_->ctimensec);
}

static	size_t iov_length(const struct iovec *iov, size_t count)
{
  size_t seg;
  size_t ret = 0;

  for (seg = 0; seg < count; seg++)
    ret += iov[seg].iov_len;
  return ret;
}

static void list_init_req(struct fuse_req *req)
{
  req->next = req;
  req->prev = req;
}

static void list_del_req(struct fuse_req *req)
{
  struct fuse_req *prev = req->prev;
  struct fuse_req *next = req->next;
  prev->next = next;
  next->prev = prev;
}

static void list_add_req(struct fuse_req *req, struct fuse_req *next)
{
  struct fuse_req *prev = next->prev;
  req->next = next;
  req->prev = prev;
  prev->next = req;
  next->prev = req;
}

static void destroy_req(fuse_req_t req)
{
  pthread_mutex_destroy(&req->lock);
  xmem_free(req);
}

void fuse_free_req(fuse_req_t req)
{
  int ctr;
  struct fuse_ll *f = req->f;

  pthread_mutex_lock(&f->lock);
  req->u.ni.func = NULL;
  req->u.ni.data = NULL;
  list_del_req(req);
  ctr = --req->ctr;
  pthread_mutex_unlock(&f->lock);
  if (!ctr)
    destroy_req(req);
}

static struct fuse_req *fuse_ll_alloc_req(struct fuse_ll *f)
{
  struct fuse_req *req;

  req = (struct fuse_req *)xmem_calloc(1, sizeof(struct fuse_req));
  if (req == NULL) {
    fprintf(stderr, "fuse: failed to allocate request\n");
  } else {
    req->f = f;
    req->ctr = 1;
    list_init_req(req);
    fuse_mutex_init(&req->lock);
  }

  return req;
}

static int fuse_send_msg(struct fuse_ll *f, struct fuse_chan *ch,
			 struct iovec *iov, int count)
{
  struct fuse_out_header *out = iov[0].iov_base;

  out->len = iov_length(iov, count);
  if (f->debug) {
    if (out->unique == 0) {
      fprintf(stderr, "NOTIFY: code=%d length=%u\n",
              out->error, out->len);
    } else if (out->error) {
      fprintf(stderr,
              "   unique: %llu, error: %i (%s), outsize: %i\n",
              (unsigned long long) out->unique, out->error,
              strerror(-out->error), out->len);
    } else {
      fprintf(stderr,
              "   unique: %llu, success, outsize: %i\n",
              (unsigned long long) out->unique, out->len);
    }
  }

  return fuse_chan_send(ch, iov, count);
}

int fuse_send_reply_iov_nofree(fuse_req_t req, int error, struct iovec *iov,
			       int count)
{
  struct fuse_out_header out;

  if (error <= -1000 || error > 0) {
    fprintf(stderr, "fuse: bad error value: %i\n",	error);
    error = -ERANGE;
  }

  out.unique = req->unique;
  out.error = error;

  iov[0].iov_base = &out;
  iov[0].iov_len = sizeof(struct fuse_out_header);

  return fuse_send_msg(req->f, req->ch, iov, count);
}

static int send_reply_iov(fuse_req_t req, int error, struct iovec *iov,
			  int count)
{
  int res;

  res = fuse_send_reply_iov_nofree(req, error, iov, count);
  fuse_free_req(req);
  return res;
}

static int send_reply(fuse_req_t req, int error, const void *arg,
		      size_t argsize)
{
  struct iovec iov[2];
  int count = 1;
  if (argsize) {
    iov[1].iov_base = (void *) arg;
    iov[1].iov_len = argsize;
    count++;
  }
  return send_reply_iov(req, error, iov, count);
}

int fuse_reply_iov(fuse_req_t req, const struct iovec *iov, int count)
{
  int res;
  struct iovec *padded_iov;

  padded_iov = xmem_malloc((count + 1) * sizeof(struct iovec));
  if (padded_iov == NULL)
    return fuse_reply_err(req, ENOMEM);

  memcpy(padded_iov + 1, iov, count * sizeof(struct iovec));
  count++;

  res = send_reply_iov(req, 0, padded_iov, count);
  xmem_free(padded_iov);

  return res;
}

size_t fuse_dirent_size(size_t namelen)
{
  return FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + namelen);
}

char *fuse_add_dirent(char *buf, const char *name, const struct stat *stbuf,
		      off_t off)
{
  unsigned namelen = strlen(name);
  unsigned entlen = FUSE_NAME_OFFSET + namelen;
  unsigned entsize = fuse_dirent_size(namelen);
  unsigned padlen = entsize - entlen;
  struct fuse_dirent *dirent = (struct fuse_dirent *) buf;

  dirent->ino = stbuf->st_ino;
  dirent->off = off;
  dirent->namelen = namelen;
  dirent->type = (stbuf->st_mode & 0170000) >> 12;
  strncpy(dirent->name, name, namelen);
  if (padlen)
    memset(buf + entlen, 0, padlen);

  return buf + entsize;
}

size_t fuse_add_direntry(fuse_req_t req, char *buf, size_t bufsize,
			 const char *name, const struct stat *stbuf, off_t off)
{
  size_t entsize;

  (void) req;
  entsize = fuse_dirent_size(strlen(name));
  if (entsize <= bufsize && buf)
    fuse_add_dirent(buf, name, stbuf, off);
  return entsize;
}

static void convert_statfs(const struct statvfs *stbuf,
			   struct fuse_kstatfs *kstatfs)
{
  kstatfs->bsize	 = stbuf->f_bsize;
  kstatfs->frsize	 = stbuf->f_frsize;
  kstatfs->blocks	 = stbuf->f_blocks;
  kstatfs->bfree	 = stbuf->f_bfree;
  kstatfs->bavail	 = stbuf->f_bavail;
  kstatfs->files	 = stbuf->f_files;
  kstatfs->ffree	 = stbuf->f_ffree;
  kstatfs->namelen = stbuf->f_namemax;
}

static int send_reply_ok(fuse_req_t req, const void *arg, size_t argsize)
{
  return send_reply(req, 0, arg, argsize);
}

int
fuse_reply_err(fuse_req_t req_,
               int        err_)
{
  return send_reply(req_,-err_,NULL,0);
}

void fuse_reply_none(fuse_req_t req)
{
  if (req->ch)
    fuse_chan_send(req->ch, NULL, 0);
  fuse_free_req(req);
}

static
void
fill_entry(struct fuse_entry_out         *arg,
           const struct fuse_entry_param *e)
{
  arg->nodeid           = e->ino;
  arg->generation       = e->generation;
  arg->entry_valid      = e->timeout.entry;
  arg->entry_valid_nsec = 0;
  arg->attr_valid       = e->timeout.attr;
  arg->attr_valid_nsec  = 0;
  convert_stat(&e->attr,&arg->attr);
}

static void fill_open(struct fuse_open_out *arg,
		      const struct fuse_file_info *f)
{
  arg->fh = f->fh;
  if (f->direct_io)
    arg->open_flags |= FOPEN_DIRECT_IO;
  if (f->keep_cache)
    arg->open_flags |= FOPEN_KEEP_CACHE;
  if (f->nonseekable)
    arg->open_flags |= FOPEN_NONSEEKABLE;
  if (f->cache_readdir)
    arg->open_flags |= FOPEN_CACHE_DIR;
}

int fuse_reply_entry(fuse_req_t req, const struct fuse_entry_param *e)
{
  struct fuse_entry_out arg;
  size_t size = req->f->conn.proto_minor < 9 ?
    FUSE_COMPAT_ENTRY_OUT_SIZE : sizeof(arg);

  /* before ABI 7.4 e->ino == 0 was invalid, only ENOENT meant
     negative entry */
  if (!e->ino && req->f->conn.proto_minor < 4)
    return fuse_reply_err(req, ENOENT);

  memset(&arg, 0, sizeof(arg));
  fill_entry(&arg, e);
  return send_reply_ok(req, &arg, size);
}

int fuse_reply_create(fuse_req_t req, const struct fuse_entry_param *e,
		      const struct fuse_file_info *f)
{
  char buf[sizeof(struct fuse_entry_out) + sizeof(struct fuse_open_out)];
  size_t entrysize = req->f->conn.proto_minor < 9 ?
    FUSE_COMPAT_ENTRY_OUT_SIZE : sizeof(struct fuse_entry_out);
  struct fuse_entry_out *earg = (struct fuse_entry_out *) buf;
  struct fuse_open_out *oarg = (struct fuse_open_out *) (buf + entrysize);

  memset(buf, 0, sizeof(buf));
  fill_entry(earg, e);
  fill_open(oarg, f);
  return send_reply_ok(req, buf,
                       entrysize + sizeof(struct fuse_open_out));
}

int
fuse_reply_attr(fuse_req_t         req,
                const struct stat *attr,
                const uint64_t     timeout)
{
  struct fuse_attr_out arg;
  size_t size = req->f->conn.proto_minor < 9 ?
    FUSE_COMPAT_ATTR_OUT_SIZE : sizeof(arg);

  memset(&arg,0,sizeof(arg));
  arg.attr_valid      = timeout;
  arg.attr_valid_nsec = 0;
  convert_stat(attr,&arg.attr);

  return send_reply_ok(req,&arg,size);
}

int fuse_reply_readlink(fuse_req_t req, const char *linkname)
{
  return send_reply_ok(req, linkname, strlen(linkname));
}

int fuse_reply_open(fuse_req_t req, const struct fuse_file_info *f)
{
  struct fuse_open_out arg;

  memset(&arg, 0, sizeof(arg));
  fill_open(&arg, f);
  return send_reply_ok(req, &arg, sizeof(arg));
}

int fuse_reply_write(fuse_req_t req, size_t count)
{
  struct fuse_write_out arg;

  memset(&arg, 0, sizeof(arg));
  arg.size = count;

  return send_reply_ok(req, &arg, sizeof(arg));
}

int fuse_reply_buf(fuse_req_t req, const char *buf, size_t size)
{
  return send_reply_ok(req, buf, size);
}

static int fuse_send_data_iov_fallback(struct fuse_ll *f, struct fuse_chan *ch,
				       struct iovec *iov, int iov_count,
				       struct fuse_bufvec *buf,
				       size_t len)
{
  struct fuse_bufvec mem_buf = FUSE_BUFVEC_INIT(len);
  void *mbuf;
  int res;

  /* Optimize common case */
  if (buf->count == 1 && buf->idx == 0 && buf->off == 0 &&
      !(buf->buf[0].flags & FUSE_BUF_IS_FD)) {
    /* FIXME: also avoid memory copy if there are multiple buffers
       but none of them contain an fd */

    iov[iov_count].iov_base = buf->buf[0].mem;
    iov[iov_count].iov_len = len;
    iov_count++;
    return fuse_send_msg(f, ch, iov, iov_count);
  }

  res = posix_memalign(&mbuf, pagesize, len);
  if (res != 0)
    return res;

  mem_buf.buf[0].mem = mbuf;
  res = fuse_buf_copy(&mem_buf, buf, 0);
  if (res < 0) {
    xmem_free(mbuf);
    return -res;
  }
  len = res;

  iov[iov_count].iov_base = mbuf;
  iov[iov_count].iov_len = len;
  iov_count++;
  res = fuse_send_msg(f, ch, iov, iov_count);
  xmem_free(mbuf);

  return res;
}

struct fuse_ll_pipe {
  size_t size;
  int can_grow;
  int pipe[2];
};

static void fuse_ll_pipe_free(struct fuse_ll_pipe *llp)
{
  close(llp->pipe[0]);
  close(llp->pipe[1]);
  xmem_free(llp);
}

#ifdef HAVE_SPLICE
static struct fuse_ll_pipe *fuse_ll_get_pipe(struct fuse_ll *f)
{
  struct fuse_ll_pipe *llp = pthread_getspecific(f->pipe_key);
  if (llp == NULL) {
    int res;

    llp = xmem_malloc(sizeof(struct fuse_ll_pipe));
    if (llp == NULL)
      return NULL;

    res = pipe(llp->pipe);
    if (res == -1) {
      xmem_free(llp);
      return NULL;
    }

    if (fcntl(llp->pipe[0], F_SETFL, O_NONBLOCK) == -1 ||
        fcntl(llp->pipe[1], F_SETFL, O_NONBLOCK) == -1) {
      close(llp->pipe[0]);
      close(llp->pipe[1]);
      xmem_free(llp);
      return NULL;
    }

    /*
     *the default size is 16 pages on linux
     */
    llp->size = pagesize * 16;
    llp->can_grow = 1;

    pthread_setspecific(f->pipe_key, llp);
  }

  return llp;
}
#endif

static void fuse_ll_clear_pipe(struct fuse_ll *f)
{
  struct fuse_ll_pipe *llp = pthread_getspecific(f->pipe_key);
  if (llp) {
    pthread_setspecific(f->pipe_key, NULL);
    fuse_ll_pipe_free(llp);
  }
}

#if defined(HAVE_SPLICE) && defined(HAVE_VMSPLICE)
static int read_back(int fd, char *buf, size_t len)
{
  int res;

  res = read(fd, buf, len);
  if (res == -1) {
    fprintf(stderr, "fuse: internal error: failed to read back from pipe: %s\n", strerror(errno));
    return -EIO;
  }
  if (res != len) {
    fprintf(stderr, "fuse: internal error: short read back from pipe: %i from %zi\n", res, len);
    return -EIO;
  }
  return 0;
}

static int fuse_send_data_iov(struct fuse_ll *f, struct fuse_chan *ch,
                              struct iovec *iov, int iov_count,
                              struct fuse_bufvec *buf, unsigned int flags)
{
  int res;
  size_t len = fuse_buf_size(buf);
  struct fuse_out_header *out = iov[0].iov_base;
  struct fuse_ll_pipe *llp;
  int splice_flags;
  size_t pipesize;
  size_t total_fd_size;
  size_t idx;
  size_t headerlen;
  struct fuse_bufvec pipe_buf = FUSE_BUFVEC_INIT(len);

  if (f->broken_splice_nonblock)
    goto fallback;

  if (flags & FUSE_BUF_NO_SPLICE)
    goto fallback;

  total_fd_size = 0;
  for (idx = buf->idx; idx < buf->count; idx++) {
    if (buf->buf[idx].flags & FUSE_BUF_IS_FD) {
      total_fd_size = buf->buf[idx].size;
      if (idx == buf->idx)
        total_fd_size -= buf->off;
    }
  }
  if (total_fd_size < 2 * pagesize)
    goto fallback;

  if (f->conn.proto_minor < 14 ||
      !(f->conn.want & FUSE_CAP_SPLICE_WRITE))
    goto fallback;

  llp = fuse_ll_get_pipe(f);
  if (llp == NULL)
    goto fallback;


  headerlen = iov_length(iov, iov_count);

  out->len = headerlen + len;

  /*
   * Heuristic for the required pipe size, does not work if the
   * source contains less than page size fragments
   */
  pipesize = pagesize * (iov_count + buf->count + 1) + out->len;

  if (llp->size < pipesize) {
    if (llp->can_grow) {
      res = fcntl(llp->pipe[0], F_SETPIPE_SZ, pipesize);
      if (res == -1) {
        llp->can_grow = 0;
        goto fallback;
      }
      llp->size = res;
    }
    if (llp->size < pipesize)
      goto fallback;
  }


  res = vmsplice(llp->pipe[1], iov, iov_count, SPLICE_F_NONBLOCK);
  if (res == -1)
    goto fallback;

  if (res != headerlen) {
    res = -EIO;
    fprintf(stderr, "fuse: short vmsplice to pipe: %u/%zu\n", res,
            headerlen);
    goto clear_pipe;
  }

  pipe_buf.buf[0].flags = FUSE_BUF_IS_FD;
  pipe_buf.buf[0].fd = llp->pipe[1];

  res = fuse_buf_copy(&pipe_buf, buf,
                      FUSE_BUF_FORCE_SPLICE | FUSE_BUF_SPLICE_NONBLOCK);
  if (res < 0) {
    if (res == -EAGAIN || res == -EINVAL) {
      /*
       * Should only get EAGAIN on kernels with
       * broken SPLICE_F_NONBLOCK support (<=
       * 2.6.35) where this error or a short read is
       * returned even if the pipe itself is not
       * full
       *
       * EINVAL might mean that splice can't handle
       * this combination of input and output.
       */
      if (res == -EAGAIN)
        f->broken_splice_nonblock = 1;

      pthread_setspecific(f->pipe_key, NULL);
      fuse_ll_pipe_free(llp);
      goto fallback;
    }
    res = -res;
    goto clear_pipe;
  }

  if (res != 0 && res < len) {
    struct fuse_bufvec mem_buf = FUSE_BUFVEC_INIT(len);
    void *mbuf;
    size_t now_len = res;
    /*
     * For regular files a short count is either
     *  1) due to EOF, or
     *  2) because of broken SPLICE_F_NONBLOCK (see above)
     *
     * For other inputs it's possible that we overflowed
     * the pipe because of small buffer fragments.
     */

    res = posix_memalign(&mbuf, pagesize, len);
    if (res != 0)
      goto clear_pipe;

    mem_buf.buf[0].mem = mbuf;
    mem_buf.off = now_len;
    res = fuse_buf_copy(&mem_buf, buf, 0);
    if (res > 0) {
      char *tmpbuf;
      size_t extra_len = res;
      /*
       * Trickiest case: got more data.  Need to get
       * back the data from the pipe and then fall
       * back to regular write.
       */
      tmpbuf = xmem_malloc(headerlen);
      if (tmpbuf == NULL) {
        xmem_free(mbuf);
        res = ENOMEM;
        goto clear_pipe;
      }
      res = read_back(llp->pipe[0], tmpbuf, headerlen);
      xmem_free(tmpbuf);
      if (res != 0) {
        xmem_free(mbuf);
        goto clear_pipe;
      }
      res = read_back(llp->pipe[0], mbuf, now_len);
      if (res != 0) {
        xmem_free(mbuf);
        goto clear_pipe;
      }
      len = now_len + extra_len;
      iov[iov_count].iov_base = mbuf;
      iov[iov_count].iov_len = len;
      iov_count++;
      res = fuse_send_msg(f, ch, iov, iov_count);
      xmem_free(mbuf);
      return res;
    }
    xmem_free(mbuf);
    res = now_len;
  }
  len = res;
  out->len = headerlen + len;

  if (f->debug) {
    fprintf(stderr,
            "   unique: %llu, success, outsize: %i (splice)\n",
            (unsigned long long) out->unique, out->len);
  }

  splice_flags = 0;
  if ((flags & FUSE_BUF_SPLICE_MOVE) &&
      (f->conn.want & FUSE_CAP_SPLICE_MOVE))
    splice_flags |= SPLICE_F_MOVE;

  res = splice(llp->pipe[0], NULL,
               fuse_chan_fd(ch), NULL, out->len, splice_flags);
  if (res == -1) {
    res = -errno;
    perror("fuse: splice from pipe");
    goto clear_pipe;
  }
  if (res != out->len) {
    res = -EIO;
    fprintf(stderr, "fuse: short splice from pipe: %u/%u\n",
            res, out->len);
    goto clear_pipe;
  }
  return 0;

 clear_pipe:
  fuse_ll_clear_pipe(f);
  return res;

 fallback:
  return fuse_send_data_iov_fallback(f, ch, iov, iov_count, buf, len);
}
#else
static int fuse_send_data_iov(struct fuse_ll *f, struct fuse_chan *ch,
                              struct iovec *iov, int iov_count,
                              struct fuse_bufvec *buf, unsigned int flags)
{
  size_t len = fuse_buf_size(buf);
  (void) flags;

  return fuse_send_data_iov_fallback(f, ch, iov, iov_count, buf, len);
}
#endif

int fuse_reply_data(fuse_req_t req, struct fuse_bufvec *bufv,
		    enum fuse_buf_copy_flags flags)
{
  struct iovec iov[2];
  struct fuse_out_header out;
  int res;

  iov[0].iov_base = &out;
  iov[0].iov_len = sizeof(struct fuse_out_header);

  out.unique = req->unique;
  out.error = 0;

  res = fuse_send_data_iov(req->f, req->ch, iov, 1, bufv, flags);
  if (res <= 0) {
    fuse_free_req(req);
    return res;
  } else {
    return fuse_reply_err(req, res);
  }
}

int fuse_reply_statfs(fuse_req_t req, const struct statvfs *stbuf)
{
  struct fuse_statfs_out arg;
  size_t size = req->f->conn.proto_minor < 4 ?
    FUSE_COMPAT_STATFS_SIZE : sizeof(arg);

  memset(&arg, 0, sizeof(arg));
  convert_statfs(stbuf, &arg.st);

  return send_reply_ok(req, &arg, size);
}

int fuse_reply_xattr(fuse_req_t req, size_t count)
{
  struct fuse_getxattr_out arg;

  memset(&arg, 0, sizeof(arg));
  arg.size = count;

  return send_reply_ok(req, &arg, sizeof(arg));
}

int fuse_reply_lock(fuse_req_t req, const struct flock *lock)
{
  struct fuse_lk_out arg;

  memset(&arg, 0, sizeof(arg));
  arg.lk.type = lock->l_type;
  if (lock->l_type != F_UNLCK) {
    arg.lk.start = lock->l_start;
    if (lock->l_len == 0)
      arg.lk.end = OFFSET_MAX;
    else
      arg.lk.end = lock->l_start + lock->l_len - 1;
  }
  arg.lk.pid = lock->l_pid;
  return send_reply_ok(req, &arg, sizeof(arg));
}

int fuse_reply_bmap(fuse_req_t req, uint64_t idx)
{
  struct fuse_bmap_out arg;

  memset(&arg, 0, sizeof(arg));
  arg.block = idx;

  return send_reply_ok(req, &arg, sizeof(arg));
}

static struct fuse_ioctl_iovec *fuse_ioctl_iovec_copy(const struct iovec *iov,
						      size_t count)
{
  struct fuse_ioctl_iovec *fiov;
  size_t i;

  fiov = xmem_malloc(sizeof(fiov[0]) * count);
  if (!fiov)
    return NULL;

  for (i = 0; i < count; i++) {
    fiov[i].base = (uintptr_t) iov[i].iov_base;
    fiov[i].len = iov[i].iov_len;
  }

  return fiov;
}

int fuse_reply_ioctl_retry(fuse_req_t req,
			   const struct iovec *in_iov, size_t in_count,
			   const struct iovec *out_iov, size_t out_count)
{
  struct fuse_ioctl_out arg;
  struct fuse_ioctl_iovec *in_fiov = NULL;
  struct fuse_ioctl_iovec *out_fiov = NULL;
  struct iovec iov[4];
  size_t count = 1;
  int res;

  memset(&arg, 0, sizeof(arg));
  arg.flags |= FUSE_IOCTL_RETRY;
  arg.in_iovs = in_count;
  arg.out_iovs = out_count;
  iov[count].iov_base = &arg;
  iov[count].iov_len = sizeof(arg);
  count++;

  if (req->f->conn.proto_minor < 16) {
    if (in_count) {
      iov[count].iov_base = (void *)in_iov;
      iov[count].iov_len = sizeof(in_iov[0]) * in_count;
      count++;
    }

    if (out_count) {
      iov[count].iov_base = (void *)out_iov;
      iov[count].iov_len = sizeof(out_iov[0]) * out_count;
      count++;
    }
  } else {
    /* Can't handle non-compat 64bit ioctls on 32bit */
    if (sizeof(void *) == 4 && req->ioctl_64bit) {
      res = fuse_reply_err(req, EINVAL);
      goto out;
    }

    if (in_count) {
      in_fiov = fuse_ioctl_iovec_copy(in_iov, in_count);
      if (!in_fiov)
        goto enomem;

      iov[count].iov_base = (void *)in_fiov;
      iov[count].iov_len = sizeof(in_fiov[0]) * in_count;
      count++;
    }
    if (out_count) {
      out_fiov = fuse_ioctl_iovec_copy(out_iov, out_count);
      if (!out_fiov)
        goto enomem;

      iov[count].iov_base = (void *)out_fiov;
      iov[count].iov_len = sizeof(out_fiov[0]) * out_count;
      count++;
    }
  }

  res = send_reply_iov(req, 0, iov, count);
 out:
  xmem_free(in_fiov);
  xmem_free(out_fiov);

  return res;

 enomem:
  res = fuse_reply_err(req, ENOMEM);
  goto out;
}

int fuse_reply_ioctl(fuse_req_t req, int result, const void *buf, uint32_t size)
{
  int count;
  struct iovec iov[3];
  struct fuse_ioctl_out arg;

  arg.result   = result;
  arg.flags    = 0;
  arg.in_iovs  = 0;
  arg.out_iovs = 0;

  count = 1;
  iov[count].iov_base = &arg;
  iov[count].iov_len  = sizeof(arg);
  count++;

  if(size)
    {
      iov[count].iov_base = (char*)buf;
      iov[count].iov_len  = size;
      count++;
    }

  return send_reply_iov(req, 0, iov, count);
}

int fuse_reply_ioctl_iov(fuse_req_t req, int result, const struct iovec *iov,
			 int count)
{
  struct iovec *padded_iov;
  struct fuse_ioctl_out arg;
  int res;

  padded_iov = xmem_malloc((count + 2) * sizeof(struct iovec));
  if (padded_iov == NULL)
    return fuse_reply_err(req, ENOMEM);

  memset(&arg, 0, sizeof(arg));
  arg.result = result;
  padded_iov[1].iov_base = &arg;
  padded_iov[1].iov_len = sizeof(arg);

  memcpy(&padded_iov[2], iov, count * sizeof(struct iovec));

  res = send_reply_iov(req, 0, padded_iov, count + 2);
  xmem_free(padded_iov);

  return res;
}

int fuse_reply_poll(fuse_req_t req, unsigned revents)
{
  struct fuse_poll_out arg;

  memset(&arg, 0, sizeof(arg));
  arg.revents = revents;

  return send_reply_ok(req, &arg, sizeof(arg));
}

static void do_lookup(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  char *name = (char *) inarg;

  if (req->f->op.lookup)
    req->f->op.lookup(req, nodeid, name);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_forget(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_forget_in *arg = (struct fuse_forget_in *) inarg;

  if (req->f->op.forget)
    req->f->op.forget(req, nodeid, arg->nlookup);
  else
    fuse_reply_none(req);
}

static void do_batch_forget(fuse_req_t req, fuse_ino_t nodeid,
			    const void *inarg)
{
  struct fuse_batch_forget_in *arg = (void *) inarg;
  struct fuse_forget_one *param = (void *) PARAM(arg);
  unsigned int i;

  (void) nodeid;

  if (req->f->op.forget_multi) {
    req->f->op.forget_multi(req, arg->count,
                            (struct fuse_forget_data *) param);
  } else if (req->f->op.forget) {
    for (i = 0; i < arg->count; i++) {
      struct fuse_forget_one *forget = &param[i];
      struct fuse_req *dummy_req;

      dummy_req = fuse_ll_alloc_req(req->f);
      if (dummy_req == NULL)
        break;

      dummy_req->unique = req->unique;
      dummy_req->ctx = req->ctx;
      dummy_req->ch = NULL;

      req->f->op.forget(dummy_req, forget->nodeid,
                        forget->nlookup);
    }
    fuse_reply_none(req);
  } else {
    fuse_reply_none(req);
  }
}

static void do_getattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_file_info *fip = NULL;
  struct fuse_file_info fi;

  if (req->f->conn.proto_minor >= 9) {
    struct fuse_getattr_in *arg = (struct fuse_getattr_in *) inarg;

    if (arg->getattr_flags & FUSE_GETATTR_FH) {
      memset(&fi, 0, sizeof(fi));
      fi.fh = arg->fh;
      fip = &fi;
    }
  }

  if (req->f->op.getattr)
    req->f->op.getattr(req, nodeid, fip);
  else
    fuse_reply_err(req, ENOSYS);
}

static
void
do_setattr(fuse_req_t  req_,
           fuse_ino_t  nodeid_,
           const void *inarg_)
{
  struct stat stbuf;
  struct fuse_file_info *fi;
  struct fuse_file_info fi_store;
  struct fuse_setattr_in *arg;

  if(req_->f->op.setattr == NULL)
    return (void)fuse_reply_err(req_,ENOSYS);

  fi = NULL;
  arg = (struct fuse_setattr_in*)inarg_;

  memset(&stbuf,0,sizeof(stbuf));
  convert_attr(arg,&stbuf);

  if(arg->valid & FATTR_FH)
    {
      arg->valid &= ~FATTR_FH;
      memset(&fi_store,0,sizeof(fi_store));
      fi = &fi_store;
      fi->fh = arg->fh;
    }

  arg->valid &=
    (FATTR_MODE      |
     FATTR_UID       |
     FATTR_GID       |
     FATTR_SIZE      |
     FATTR_ATIME     |
     FATTR_MTIME     |
     FATTR_CTIME     |
     FATTR_ATIME_NOW |
     FATTR_MTIME_NOW);

  req_->f->op.setattr(req_,nodeid_,&stbuf,arg->valid,fi);
}

static void do_access(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_access_in *arg = (struct fuse_access_in *) inarg;

  if (req->f->op.access)
    req->f->op.access(req, nodeid, arg->mask);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_readlink(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  (void) inarg;

  if (req->f->op.readlink)
    req->f->op.readlink(req, nodeid);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_mknod(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_mknod_in *arg = (struct fuse_mknod_in *) inarg;
  char *name = PARAM(arg);

  if (req->f->conn.proto_minor >= 12)
    req->ctx.umask = arg->umask;
  else
    name = (char *) inarg + FUSE_COMPAT_MKNOD_IN_SIZE;

  if (req->f->op.mknod)
    req->f->op.mknod(req, nodeid, name, arg->mode, arg->rdev);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_mkdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_mkdir_in *arg = (struct fuse_mkdir_in *) inarg;

  if (req->f->conn.proto_minor >= 12)
    req->ctx.umask = arg->umask;

  if (req->f->op.mkdir)
    req->f->op.mkdir(req, nodeid, PARAM(arg), arg->mode);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_unlink(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  char *name = (char *) inarg;

  if (req->f->op.unlink)
    req->f->op.unlink(req, nodeid, name);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_rmdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  char *name = (char *) inarg;

  if (req->f->op.rmdir)
    req->f->op.rmdir(req, nodeid, name);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_symlink(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  char *name = (char *) inarg;
  char *linkname = ((char *) inarg) + strlen((char *) inarg) + 1;

  if (req->f->op.symlink)
    req->f->op.symlink(req, linkname, nodeid, name);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_rename(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_rename_in *arg = (struct fuse_rename_in *) inarg;
  char *oldname = PARAM(arg);
  char *newname = oldname + strlen(oldname) + 1;

  if (req->f->op.rename)
    req->f->op.rename(req, nodeid, oldname, arg->newdir, newname);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_link(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_link_in *arg = (struct fuse_link_in *) inarg;

  if (req->f->op.link)
    req->f->op.link(req, arg->oldnodeid, nodeid, PARAM(arg));
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_create(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_create_in *arg = (struct fuse_create_in *) inarg;

  if (req->f->op.create) {
    struct fuse_file_info fi;
    char *name = PARAM(arg);

    memset(&fi, 0, sizeof(fi));
    fi.flags = arg->flags;

    if (req->f->conn.proto_minor >= 12)
      req->ctx.umask = arg->umask;
    else
      name = (char *) inarg + sizeof(struct fuse_open_in);

    req->f->op.create(req, nodeid, name, arg->mode, &fi);
  } else
    fuse_reply_err(req, ENOSYS);
}

static void do_open(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_open_in *arg = (struct fuse_open_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.flags = arg->flags;

  if (req->f->op.open)
    req->f->op.open(req, nodeid, &fi);
  else
    fuse_reply_open(req, &fi);
}

static void do_read(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_read_in *arg = (struct fuse_read_in *) inarg;

  if (req->f->op.read) {
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;
    if (req->f->conn.proto_minor >= 9) {
      fi.lock_owner = arg->lock_owner;
      fi.flags = arg->flags;
    }
    req->f->op.read(req, nodeid, arg->size, arg->offset, &fi);
  } else
    fuse_reply_err(req, ENOSYS);
}

static void do_write(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_write_in *arg = (struct fuse_write_in *) inarg;
  struct fuse_file_info fi;
  char *param;

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;
  fi.writepage = arg->write_flags & 1;

  if (req->f->conn.proto_minor < 9) {
    param = ((char *) arg) + FUSE_COMPAT_WRITE_IN_SIZE;
  } else {
    fi.lock_owner = arg->lock_owner;
    fi.flags = arg->flags;
    param = PARAM(arg);
  }

  if (req->f->op.write)
    req->f->op.write(req, nodeid, param, arg->size,
                     arg->offset, &fi);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_write_buf(fuse_req_t req, fuse_ino_t nodeid, const void *inarg,
			 const struct fuse_buf *ibuf)
{
  struct fuse_ll *f = req->f;
  struct fuse_bufvec bufv = {
    .buf[0] = *ibuf,
    .count = 1,
  };
  struct fuse_write_in *arg = (struct fuse_write_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;
  fi.writepage = arg->write_flags & 1;

  if (req->f->conn.proto_minor < 9) {
    bufv.buf[0].mem = ((char *) arg) + FUSE_COMPAT_WRITE_IN_SIZE;
    bufv.buf[0].size -= sizeof(struct fuse_in_header) +
      FUSE_COMPAT_WRITE_IN_SIZE;
    assert(!(bufv.buf[0].flags & FUSE_BUF_IS_FD));
  } else {
    fi.lock_owner = arg->lock_owner;
    fi.flags = arg->flags;
    if (!(bufv.buf[0].flags & FUSE_BUF_IS_FD))
      bufv.buf[0].mem = PARAM(arg);

    bufv.buf[0].size -= sizeof(struct fuse_in_header) +
      sizeof(struct fuse_write_in);
  }
  if (bufv.buf[0].size < arg->size) {
    fprintf(stderr, "fuse: do_write_buf: buffer size too small\n");
    fuse_reply_err(req, EIO);
    goto out;
  }
  bufv.buf[0].size = arg->size;

  req->f->op.write_buf(req, nodeid, &bufv, arg->offset, &fi);

 out:
  /* Need to reset the pipe if ->write_buf() didn't consume all data */
  if ((ibuf->flags & FUSE_BUF_IS_FD) && bufv.idx < bufv.count)
    fuse_ll_clear_pipe(f);
}

static void do_flush(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_flush_in *arg = (struct fuse_flush_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;
  fi.flush = 1;
  if (req->f->conn.proto_minor >= 7)
    fi.lock_owner = arg->lock_owner;

  if (req->f->op.flush)
    req->f->op.flush(req, nodeid, &fi);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_release(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_release_in *arg = (struct fuse_release_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.flags = arg->flags;
  fi.fh = arg->fh;
  if (req->f->conn.proto_minor >= 8) {
    fi.flush = (arg->release_flags & FUSE_RELEASE_FLUSH) ? 1 : 0;
    fi.lock_owner = arg->lock_owner;
  }
  if (arg->release_flags & FUSE_RELEASE_FLOCK_UNLOCK) {
    fi.flock_release = 1;
    fi.lock_owner = arg->lock_owner;
  }

  if (req->f->op.release)
    req->f->op.release(req, nodeid, &fi);
  else
    fuse_reply_err(req, 0);
}

static void do_fsync(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_fsync_in *arg = (struct fuse_fsync_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;

  if (req->f->op.fsync)
    req->f->op.fsync(req, nodeid, arg->fsync_flags & 1, &fi);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_opendir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_open_in *arg = (struct fuse_open_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.flags = arg->flags;

  if (req->f->op.opendir)
    req->f->op.opendir(req, nodeid, &fi);
  else
    fuse_reply_open(req, &fi);
}

static void do_readdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_read_in *arg = (struct fuse_read_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;

  if (req->f->op.readdir)
    req->f->op.readdir(req, nodeid, arg->size, arg->offset, &fi);
  else
    fuse_reply_err(req, ENOSYS);
}

static
void
do_readdir_plus(fuse_req_t  req_,
                fuse_ino_t  nodeid_,
                const void *inarg_)
{
  const struct fuse_read_in *arg;
  struct fuse_file_info ffi = {0};

  arg    = (struct fuse_read_in*)inarg_;
  ffi.fh = arg->fh;

  if(req_->f->op.readdir_plus)
    req_->f->op.readdir_plus(req_,nodeid_,arg->size,arg->offset,&ffi);
  else
    fuse_reply_err(req_,ENOSYS);
}

static void do_releasedir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_release_in *arg = (struct fuse_release_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.flags = arg->flags;
  fi.fh = arg->fh;

  if (req->f->op.releasedir)
    req->f->op.releasedir(req, nodeid, &fi);
  else
    fuse_reply_err(req, 0);
}

static void do_fsyncdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_fsync_in *arg = (struct fuse_fsync_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;

  if (req->f->op.fsyncdir)
    req->f->op.fsyncdir(req, nodeid, arg->fsync_flags & 1, &fi);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_statfs(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  (void) nodeid;
  (void) inarg;

  if (req->f->op.statfs)
    req->f->op.statfs(req, nodeid);
  else {
    struct statvfs buf = {
      .f_namemax = 255,
      .f_bsize = 512,
    };
    fuse_reply_statfs(req, &buf);
  }
}

static void do_setxattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_setxattr_in *arg = (struct fuse_setxattr_in *) inarg;
  char *name = PARAM(arg);
  char *value = name + strlen(name) + 1;

  if (req->f->op.setxattr)
    req->f->op.setxattr(req, nodeid, name, value, arg->size,
                        arg->flags);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_getxattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_getxattr_in *arg = (struct fuse_getxattr_in *) inarg;

  if (req->f->op.getxattr)
    req->f->op.getxattr(req, nodeid, PARAM(arg), arg->size);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_listxattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_getxattr_in *arg = (struct fuse_getxattr_in *) inarg;

  if (req->f->op.listxattr)
    req->f->op.listxattr(req, nodeid, arg->size);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_removexattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  char *name = (char *) inarg;

  if (req->f->op.removexattr)
    req->f->op.removexattr(req, nodeid, name);
  else
    fuse_reply_err(req, ENOSYS);
}

static void convert_fuse_file_lock(struct fuse_file_lock *fl,
				   struct flock *flock)
{
  memset(flock, 0, sizeof(struct flock));
  flock->l_type = fl->type;
  flock->l_whence = SEEK_SET;
  flock->l_start = fl->start;
  if (fl->end == OFFSET_MAX)
    flock->l_len = 0;
  else
    flock->l_len = fl->end - fl->start + 1;
  flock->l_pid = fl->pid;
}

static void do_getlk(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_lk_in *arg = (struct fuse_lk_in *) inarg;
  struct fuse_file_info fi;
  struct flock flock;

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;
  fi.lock_owner = arg->owner;

  convert_fuse_file_lock(&arg->lk, &flock);
  if (req->f->op.getlk)
    req->f->op.getlk(req, nodeid, &fi, &flock);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_setlk_common(fuse_req_t req, fuse_ino_t nodeid,
			    const void *inarg, int sleep)
{
  struct fuse_lk_in *arg = (struct fuse_lk_in *) inarg;
  struct fuse_file_info fi;
  struct flock flock;

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;
  fi.lock_owner = arg->owner;

  if (arg->lk_flags & FUSE_LK_FLOCK) {
    int op = 0;

    switch (arg->lk.type) {
    case F_RDLCK:
      op = LOCK_SH;
      break;
    case F_WRLCK:
      op = LOCK_EX;
      break;
    case F_UNLCK:
      op = LOCK_UN;
      break;
    }
    if (!sleep)
      op |= LOCK_NB;

    if (req->f->op.flock)
      req->f->op.flock(req, nodeid, &fi, op);
    else
      fuse_reply_err(req, ENOSYS);
  } else {
    convert_fuse_file_lock(&arg->lk, &flock);
    if (req->f->op.setlk)
      req->f->op.setlk(req, nodeid, &fi, &flock, sleep);
    else
      fuse_reply_err(req, ENOSYS);
  }
}

static void do_setlk(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  do_setlk_common(req, nodeid, inarg, 0);
}

static void do_setlkw(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  do_setlk_common(req, nodeid, inarg, 1);
}

static int find_interrupted(struct fuse_ll *f, struct fuse_req *req)
{
  struct fuse_req *curr;

  for (curr = f->list.next; curr != &f->list; curr = curr->next) {
    if (curr->unique == req->u.i.unique) {
      fuse_interrupt_func_t func;
      void *data;

      curr->ctr++;
      pthread_mutex_unlock(&f->lock);

      /* Ugh, ugly locking */
      pthread_mutex_lock(&curr->lock);
      pthread_mutex_lock(&f->lock);
      curr->interrupted = 1;
      func = curr->u.ni.func;
      data = curr->u.ni.data;
      pthread_mutex_unlock(&f->lock);
      if (func)
        func(curr, data);
      pthread_mutex_unlock(&curr->lock);

      pthread_mutex_lock(&f->lock);
      curr->ctr--;
      if (!curr->ctr)
        destroy_req(curr);

      return 1;
    }
  }
  for (curr = f->interrupts.next; curr != &f->interrupts;
       curr = curr->next) {
    if (curr->u.i.unique == req->u.i.unique)
      return 1;
  }
  return 0;
}

static void do_interrupt(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_interrupt_in *arg = (struct fuse_interrupt_in *) inarg;
  struct fuse_ll *f = req->f;

  (void) nodeid;
  if (f->debug)
    fprintf(stderr, "INTERRUPT: %llu\n",
            (unsigned long long) arg->unique);

  req->u.i.unique = arg->unique;

  pthread_mutex_lock(&f->lock);
  if (find_interrupted(f, req))
    destroy_req(req);
  else
    list_add_req(req, &f->interrupts);
  pthread_mutex_unlock(&f->lock);
}

static struct fuse_req *check_interrupt(struct fuse_ll *f, struct fuse_req *req)
{
  struct fuse_req *curr;

  for (curr = f->interrupts.next; curr != &f->interrupts;
       curr = curr->next) {
    if (curr->u.i.unique == req->unique) {
      req->interrupted = 1;
      list_del_req(curr);
      xmem_free(curr);
      return NULL;
    }
  }
  curr = f->interrupts.next;
  if (curr != &f->interrupts) {
    list_del_req(curr);
    list_init_req(curr);
    return curr;
  } else
    return NULL;
}

static void do_bmap(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_bmap_in *arg = (struct fuse_bmap_in *) inarg;

  if (req->f->op.bmap)
    req->f->op.bmap(req, nodeid, arg->blocksize, arg->block);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_ioctl(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_ioctl_in *arg = (struct fuse_ioctl_in *) inarg;
  unsigned int flags = arg->flags;
  void *in_buf = arg->in_size ? PARAM(arg) : NULL;
  struct fuse_file_info fi;

  if (flags & FUSE_IOCTL_DIR &&
      !(req->f->conn.want & FUSE_CAP_IOCTL_DIR)) {
    fuse_reply_err(req, ENOTTY);
    return;
  }

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;

  if (sizeof(void *) == 4 && req->f->conn.proto_minor >= 16 &&
      !(flags & FUSE_IOCTL_32BIT)) {
    req->ioctl_64bit = 1;
  }

  if (req->f->op.ioctl)
    req->f->op.ioctl(req, nodeid, (unsigned long)arg->cmd,
                     (void *)(uintptr_t)arg->arg, &fi, flags,
                     in_buf, arg->in_size, arg->out_size);
  else
    fuse_reply_err(req, ENOSYS);
}

void fuse_pollhandle_destroy(struct fuse_pollhandle *ph)
{
  xmem_free(ph);
}

static void do_poll(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_poll_in *arg = (struct fuse_poll_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;

  if (req->f->op.poll) {
    struct fuse_pollhandle *ph = NULL;

    if (arg->flags & FUSE_POLL_SCHEDULE_NOTIFY) {
      ph = xmem_malloc(sizeof(struct fuse_pollhandle));
      if (ph == NULL) {
        fuse_reply_err(req, ENOMEM);
        return;
      }
      ph->kh = arg->kh;
      ph->ch = req->ch;
      ph->f = req->f;
    }

    req->f->op.poll(req, nodeid, &fi, ph);
  } else {
    fuse_reply_err(req, ENOSYS);
  }
}

static void do_fallocate(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_fallocate_in *arg = (struct fuse_fallocate_in *) inarg;
  struct fuse_file_info fi;

  memset(&fi, 0, sizeof(fi));
  fi.fh = arg->fh;

  if (req->f->op.fallocate)
    req->f->op.fallocate(req, nodeid, arg->mode, arg->offset, arg->length, &fi);
  else
    fuse_reply_err(req, ENOSYS);
}

static void do_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_init_in *arg = (struct fuse_init_in *) inarg;
  struct fuse_init_out outarg;
  struct fuse_ll *f = req->f;
  size_t bufsize = fuse_chan_bufsize(req->ch);

  (void) nodeid;
  if (f->debug) {
    fprintf(stderr, "INIT: %u.%u\n", arg->major, arg->minor);
    if (arg->major == 7 && arg->minor >= 6) {
      fprintf(stderr, "flags=0x%08x\n", arg->flags);
      fprintf(stderr, "max_readahead=0x%08x\n",
              arg->max_readahead);
    }
  }
  f->conn.proto_major = arg->major;
  f->conn.proto_minor = arg->minor;
  f->conn.capable = 0;
  f->conn.want = 0;

  memset(&outarg, 0, sizeof(outarg));

  outarg.major     = FUSE_KERNEL_VERSION;
  outarg.minor     = FUSE_KERNEL_MINOR_VERSION;
  outarg.max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;

  if (arg->major < 7) {
    fprintf(stderr, "fuse: unsupported protocol version: %u.%u\n",
            arg->major, arg->minor);
    fuse_reply_err(req, EPROTO);
    return;
  }

  if (arg->major > 7) {
    /* Wait for a second INIT request with a 7.X version */
    send_reply_ok(req, &outarg, sizeof(outarg));
    return;
  }

  if (arg->minor >= 6) {
    if (arg->max_readahead < f->conn.max_readahead)
      f->conn.max_readahead = arg->max_readahead;
    if (arg->flags & FUSE_ASYNC_READ)
      f->conn.capable |= FUSE_CAP_ASYNC_READ;
    if (arg->flags & FUSE_POSIX_LOCKS)
      f->conn.capable |= FUSE_CAP_POSIX_LOCKS;
    if (arg->flags & FUSE_ATOMIC_O_TRUNC)
      f->conn.capable |= FUSE_CAP_ATOMIC_O_TRUNC;
    if (arg->flags & FUSE_EXPORT_SUPPORT)
      f->conn.capable |= FUSE_CAP_EXPORT_SUPPORT;
    if (arg->flags & FUSE_BIG_WRITES)
      f->conn.capable |= FUSE_CAP_BIG_WRITES;
    if (arg->flags & FUSE_DONT_MASK)
      f->conn.capable |= FUSE_CAP_DONT_MASK;
    if (arg->flags & FUSE_FLOCK_LOCKS)
      f->conn.capable |= FUSE_CAP_FLOCK_LOCKS;
    if (arg->flags & FUSE_POSIX_ACL)
      f->conn.capable |= FUSE_CAP_POSIX_ACL;
    if (arg->flags & FUSE_CACHE_SYMLINKS)
      f->conn.capable |= FUSE_CAP_CACHE_SYMLINKS;
    if (arg->flags & FUSE_ASYNC_DIO)
      f->conn.capable |= FUSE_CAP_ASYNC_DIO;
    if (arg->flags & FUSE_PARALLEL_DIROPS)
      f->conn.capable |= FUSE_CAP_PARALLEL_DIROPS;
    if (arg->flags & FUSE_MAX_PAGES)
      f->conn.capable |= FUSE_CAP_MAX_PAGES;
    if (arg->flags & FUSE_WRITEBACK_CACHE)
      f->conn.capable |= FUSE_CAP_WRITEBACK_CACHE;
    if (arg->flags & FUSE_DO_READDIRPLUS)
      f->conn.capable |= FUSE_CAP_READDIR_PLUS;
    if (arg->flags & FUSE_READDIRPLUS_AUTO)
      f->conn.capable |= FUSE_CAP_READDIR_PLUS_AUTO;
  } else {
    f->conn.want &= ~FUSE_CAP_ASYNC_READ;
    f->conn.max_readahead = 0;
  }

  if (req->f->conn.proto_minor >= 14) {
#ifdef HAVE_SPLICE
#ifdef HAVE_VMSPLICE
    f->conn.capable |= FUSE_CAP_SPLICE_WRITE | FUSE_CAP_SPLICE_MOVE;
    if (f->splice_write)
      f->conn.want |= FUSE_CAP_SPLICE_WRITE;
    if (f->splice_move)
      f->conn.want |= FUSE_CAP_SPLICE_MOVE;
#endif
    f->conn.capable |= FUSE_CAP_SPLICE_READ;
    if (f->splice_read)
      f->conn.want |= FUSE_CAP_SPLICE_READ;
#endif
  }
  if (req->f->conn.proto_minor >= 18)
    f->conn.capable |= FUSE_CAP_IOCTL_DIR;

  if (f->op.getlk && f->op.setlk && !f->no_remote_posix_lock)
    f->conn.want |= FUSE_CAP_POSIX_LOCKS;
  if (f->op.flock && !f->no_remote_flock)
    f->conn.want |= FUSE_CAP_FLOCK_LOCKS;

  if (bufsize < FUSE_MIN_READ_BUFFER) {
    fprintf(stderr, "fuse: warning: buffer size too small: %zu\n",
            bufsize);
    bufsize = FUSE_MIN_READ_BUFFER;
  }

  bufsize -= 4096;
  if (bufsize < f->conn.max_write)
    f->conn.max_write = bufsize;

  f->got_init = 1;
  if (f->op.init)
    f->op.init(f->userdata, &f->conn);

  if (f->no_splice_read)
    f->conn.want &= ~FUSE_CAP_SPLICE_READ;
  if (f->no_splice_write)
    f->conn.want &= ~FUSE_CAP_SPLICE_WRITE;
  if (f->no_splice_move)
    f->conn.want &= ~FUSE_CAP_SPLICE_MOVE;

  if ((arg->flags & FUSE_MAX_PAGES) && (f->conn.want & FUSE_CAP_MAX_PAGES))
    {
      outarg.flags     |= FUSE_MAX_PAGES;
      outarg.max_pages  = f->conn.max_pages;
    }

  if (f->conn.want & FUSE_CAP_ASYNC_READ)
    outarg.flags |= FUSE_ASYNC_READ;
  if (f->conn.want & FUSE_CAP_POSIX_LOCKS)
    outarg.flags |= FUSE_POSIX_LOCKS;
  if (f->conn.want & FUSE_CAP_ATOMIC_O_TRUNC)
    outarg.flags |= FUSE_ATOMIC_O_TRUNC;
  if (f->conn.want & FUSE_CAP_EXPORT_SUPPORT)
    outarg.flags |= FUSE_EXPORT_SUPPORT;
  if (f->conn.want & FUSE_CAP_BIG_WRITES)
    outarg.flags |= FUSE_BIG_WRITES;
  if (f->conn.want & FUSE_CAP_DONT_MASK)
    outarg.flags |= FUSE_DONT_MASK;
  if (f->conn.want & FUSE_CAP_FLOCK_LOCKS)
    outarg.flags |= FUSE_FLOCK_LOCKS;
  if (f->conn.want & FUSE_CAP_POSIX_ACL)
    outarg.flags |= FUSE_POSIX_ACL;
  if (f->conn.want & FUSE_CAP_CACHE_SYMLINKS)
    outarg.flags |= FUSE_CACHE_SYMLINKS;
  if (f->conn.want & FUSE_CAP_ASYNC_DIO)
    outarg.flags |= FUSE_ASYNC_DIO;
  if (f->conn.want & FUSE_CAP_PARALLEL_DIROPS)
    outarg.flags |= FUSE_PARALLEL_DIROPS;
  if (f->conn.want & FUSE_CAP_WRITEBACK_CACHE)
    outarg.flags |= FUSE_WRITEBACK_CACHE;
  if (f->conn.want & FUSE_CAP_READDIR_PLUS)
    outarg.flags |= FUSE_DO_READDIRPLUS;
  if (f->conn.want & FUSE_CAP_READDIR_PLUS_AUTO)
    outarg.flags |= FUSE_READDIRPLUS_AUTO;

  outarg.max_readahead = f->conn.max_readahead;
  outarg.max_write = f->conn.max_write;
  if (f->conn.proto_minor >= 13) {
    if (f->conn.max_background >= (1 << 16))
      f->conn.max_background = (1 << 16) - 1;
    if (f->conn.congestion_threshold > f->conn.max_background)
      f->conn.congestion_threshold = f->conn.max_background;
    if (!f->conn.congestion_threshold) {
      f->conn.congestion_threshold =
        f->conn.max_background * 3 / 4;
    }

    outarg.max_background = f->conn.max_background;
    outarg.congestion_threshold = f->conn.congestion_threshold;
  }

  if (f->debug) {
    fprintf(stderr, "   INIT: %u.%u\n", outarg.major, outarg.minor);
    fprintf(stderr, "   flags=0x%08x\n", outarg.flags);
    fprintf(stderr, "   max_readahead=0x%08x\n",
            outarg.max_readahead);
    fprintf(stderr, "   max_write=0x%08x\n", outarg.max_write);
    fprintf(stderr, "   max_background=%i\n",
            outarg.max_background);
    fprintf(stderr, "   congestion_threshold=%i\n",
            outarg.congestion_threshold);
    fprintf(stderr, "   max_pages=%d\n",outarg.max_pages);
  }

  size_t outargsize;
  if(arg->minor < 5)
    outargsize = FUSE_COMPAT_INIT_OUT_SIZE;
  else if(arg->minor < 23)
    outargsize = FUSE_COMPAT_22_INIT_OUT_SIZE;
  else
    outargsize = sizeof(outarg);

  send_reply_ok(req, &outarg, outargsize);
}

static void do_destroy(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
  struct fuse_ll *f = req->f;

  (void) nodeid;
  (void) inarg;

  f->got_destroy = 1;
  if (f->op.destroy)
    f->op.destroy(f->userdata);

  send_reply_ok(req, NULL, 0);
}

static void list_del_nreq(struct fuse_notify_req *nreq)
{
  struct fuse_notify_req *prev = nreq->prev;
  struct fuse_notify_req *next = nreq->next;
  prev->next = next;
  next->prev = prev;
}

static void list_add_nreq(struct fuse_notify_req *nreq,
			  struct fuse_notify_req *next)
{
  struct fuse_notify_req *prev = next->prev;
  nreq->next = next;
  nreq->prev = prev;
  prev->next = nreq;
  next->prev = nreq;
}

static void list_init_nreq(struct fuse_notify_req *nreq)
{
  nreq->next = nreq;
  nreq->prev = nreq;
}

static void do_notify_reply(fuse_req_t req, fuse_ino_t nodeid,
			    const void *inarg, const struct fuse_buf *buf)
{
  struct fuse_ll *f = req->f;
  struct fuse_notify_req *nreq;
  struct fuse_notify_req *head;

  pthread_mutex_lock(&f->lock);
  head = &f->notify_list;
  for (nreq = head->next; nreq != head; nreq = nreq->next) {
    if (nreq->unique == req->unique) {
      list_del_nreq(nreq);
      break;
    }
  }
  pthread_mutex_unlock(&f->lock);

  if (nreq != head)
    nreq->reply(nreq, req, nodeid, inarg, buf);
}

static
void
do_copy_file_range(fuse_req_t  req_,
                   fuse_ino_t  nodeid_in_,
                   const void *arg_)

{
  struct fuse_file_info ffi_in  = {0};
  struct fuse_file_info ffi_out = {0};
  struct fuse_copy_file_range_in *arg = (struct fuse_copy_file_range_in*)arg_;

  ffi_in.fh  = arg->fh_in;
  ffi_out.fh = arg->fh_out;

  if(req_->f->op.copy_file_range == NULL)
    fuse_reply_err(req_,ENOSYS);
  else
    req_->f->op.copy_file_range(req_,
                                nodeid_in_,
                                arg->off_in,
                                &ffi_in,
                                arg->nodeid_out,
                                arg->off_out,
                                &ffi_out,
                                arg->len,
                                arg->flags);
}

static int send_notify_iov(struct fuse_ll *f, struct fuse_chan *ch,
			   int notify_code, struct iovec *iov, int count)
{
  struct fuse_out_header out;

  if (!f->got_init)
    return -ENOTCONN;

  out.unique = 0;
  out.error = notify_code;
  iov[0].iov_base = &out;
  iov[0].iov_len = sizeof(struct fuse_out_header);

  return fuse_send_msg(f, ch, iov, count);
}

int fuse_lowlevel_notify_poll(struct fuse_pollhandle *ph)
{
  if (ph != NULL) {
    struct fuse_notify_poll_wakeup_out outarg;
    struct iovec iov[2];

    outarg.kh = ph->kh;

    iov[1].iov_base = &outarg;
    iov[1].iov_len = sizeof(outarg);

    return send_notify_iov(ph->f, ph->ch, FUSE_NOTIFY_POLL, iov, 2);
  } else {
    return 0;
  }
}

int fuse_lowlevel_notify_inval_inode(struct fuse_chan *ch, fuse_ino_t ino,
                                     off_t off, off_t len)
{
  struct fuse_notify_inval_inode_out outarg;
  struct fuse_ll *f;
  struct iovec iov[2];

  if (!ch)
    return -EINVAL;

  f = (struct fuse_ll *)fuse_session_data(fuse_chan_session(ch));
  if (!f)
    return -ENODEV;

  outarg.ino = ino;
  outarg.off = off;
  outarg.len = len;

  iov[1].iov_base = &outarg;
  iov[1].iov_len = sizeof(outarg);

  return send_notify_iov(f, ch, FUSE_NOTIFY_INVAL_INODE, iov, 2);
}

int fuse_lowlevel_notify_inval_entry(struct fuse_chan *ch, fuse_ino_t parent,
                                     const char *name, size_t namelen)
{
  struct fuse_notify_inval_entry_out outarg;
  struct fuse_ll *f;
  struct iovec iov[3];

  if (!ch)
    return -EINVAL;

  f = (struct fuse_ll *)fuse_session_data(fuse_chan_session(ch));
  if (!f)
    return -ENODEV;

  outarg.parent = parent;
  outarg.namelen = namelen;
  outarg.padding = 0;

  iov[1].iov_base = &outarg;
  iov[1].iov_len = sizeof(outarg);
  iov[2].iov_base = (void *)name;
  iov[2].iov_len = namelen + 1;

  return send_notify_iov(f, ch, FUSE_NOTIFY_INVAL_ENTRY, iov, 3);
}

int fuse_lowlevel_notify_delete(struct fuse_chan *ch,
				fuse_ino_t parent, fuse_ino_t child,
				const char *name, size_t namelen)
{
  struct fuse_notify_delete_out outarg;
  struct fuse_ll *f;
  struct iovec iov[3];

  if (!ch)
    return -EINVAL;

  f = (struct fuse_ll *)fuse_session_data(fuse_chan_session(ch));
  if (!f)
    return -ENODEV;

  if (f->conn.proto_minor < 18)
    return -ENOSYS;

  outarg.parent = parent;
  outarg.child = child;
  outarg.namelen = namelen;
  outarg.padding = 0;

  iov[1].iov_base = &outarg;
  iov[1].iov_len = sizeof(outarg);
  iov[2].iov_base = (void *)name;
  iov[2].iov_len = namelen + 1;

  return send_notify_iov(f, ch, FUSE_NOTIFY_DELETE, iov, 3);
}

int fuse_lowlevel_notify_store(struct fuse_chan *ch, fuse_ino_t ino,
			       off_t offset, struct fuse_bufvec *bufv,
			       enum fuse_buf_copy_flags flags)
{
  struct fuse_out_header out;
  struct fuse_notify_store_out outarg;
  struct fuse_ll *f;
  struct iovec iov[3];
  size_t size = fuse_buf_size(bufv);
  int res;

  if (!ch)
    return -EINVAL;

  f = (struct fuse_ll *)fuse_session_data(fuse_chan_session(ch));
  if (!f)
    return -ENODEV;

  if (f->conn.proto_minor < 15)
    return -ENOSYS;

  out.unique = 0;
  out.error = FUSE_NOTIFY_STORE;

  outarg.nodeid = ino;
  outarg.offset = offset;
  outarg.size = size;
  outarg.padding = 0;

  iov[0].iov_base = &out;
  iov[0].iov_len = sizeof(out);
  iov[1].iov_base = &outarg;
  iov[1].iov_len = sizeof(outarg);

  res = fuse_send_data_iov(f, ch, iov, 2, bufv, flags);
  if (res > 0)
    res = -res;

  return res;
}

struct fuse_retrieve_req {
  struct fuse_notify_req nreq;
  void *cookie;
};

static void fuse_ll_retrieve_reply(struct fuse_notify_req *nreq,
				   fuse_req_t req, fuse_ino_t ino,
				   const void *inarg,
				   const struct fuse_buf *ibuf)
{
  struct fuse_ll *f = req->f;
  struct fuse_retrieve_req *rreq =
    container_of(nreq, struct fuse_retrieve_req, nreq);
  const struct fuse_notify_retrieve_in *arg = inarg;
  struct fuse_bufvec bufv = {
    .buf[0] = *ibuf,
    .count = 1,
  };

  if (!(bufv.buf[0].flags & FUSE_BUF_IS_FD))
    bufv.buf[0].mem = PARAM(arg);

  bufv.buf[0].size -= sizeof(struct fuse_in_header) +
    sizeof(struct fuse_notify_retrieve_in);

  if (bufv.buf[0].size < arg->size) {
    fprintf(stderr, "fuse: retrieve reply: buffer size too small\n");
    fuse_reply_none(req);
    goto out;
  }
  bufv.buf[0].size = arg->size;

  if (req->f->op.retrieve_reply) {
    req->f->op.retrieve_reply(req, rreq->cookie, ino,
                              arg->offset, &bufv);
  } else {
    fuse_reply_none(req);
  }
 out:
  xmem_free(rreq);
  if ((ibuf->flags & FUSE_BUF_IS_FD) && bufv.idx < bufv.count)
    fuse_ll_clear_pipe(f);
}

int fuse_lowlevel_notify_retrieve(struct fuse_chan *ch, fuse_ino_t ino,
				  size_t size, off_t offset, void *cookie)
{
  struct fuse_notify_retrieve_out outarg;
  struct fuse_ll *f;
  struct iovec iov[2];
  struct fuse_retrieve_req *rreq;
  int err;

  if (!ch)
    return -EINVAL;

  f = (struct fuse_ll *)fuse_session_data(fuse_chan_session(ch));
  if (!f)
    return -ENODEV;

  if (f->conn.proto_minor < 15)
    return -ENOSYS;

  rreq = xmem_malloc(sizeof(*rreq));
  if (rreq == NULL)
    return -ENOMEM;

  pthread_mutex_lock(&f->lock);
  rreq->cookie = cookie;
  rreq->nreq.unique = f->notify_ctr++;
  rreq->nreq.reply = fuse_ll_retrieve_reply;
  list_add_nreq(&rreq->nreq, &f->notify_list);
  pthread_mutex_unlock(&f->lock);

  outarg.notify_unique = rreq->nreq.unique;
  outarg.nodeid = ino;
  outarg.offset = offset;
  outarg.size = size;

  iov[1].iov_base = &outarg;
  iov[1].iov_len = sizeof(outarg);

  err = send_notify_iov(f, ch, FUSE_NOTIFY_RETRIEVE, iov, 2);
  if (err) {
    pthread_mutex_lock(&f->lock);
    list_del_nreq(&rreq->nreq);
    pthread_mutex_unlock(&f->lock);
    xmem_free(rreq);
  }

  return err;
}

void *fuse_req_userdata(fuse_req_t req)
{
  return req->f->userdata;
}

const struct fuse_ctx *fuse_req_ctx(fuse_req_t req)
{
  return &req->ctx;
}

void fuse_req_interrupt_func(fuse_req_t req, fuse_interrupt_func_t func,
			     void *data)
{
  pthread_mutex_lock(&req->lock);
  pthread_mutex_lock(&req->f->lock);
  req->u.ni.func = func;
  req->u.ni.data = data;
  pthread_mutex_unlock(&req->f->lock);
  if (req->interrupted && func)
    func(req, data);
  pthread_mutex_unlock(&req->lock);
}

int fuse_req_interrupted(fuse_req_t req)
{
  int interrupted;

  pthread_mutex_lock(&req->f->lock);
  interrupted = req->interrupted;
  pthread_mutex_unlock(&req->f->lock);

  return interrupted;
}

static struct {
  void (*func)(fuse_req_t, fuse_ino_t, const void *);
  const char *name;
} fuse_ll_ops[] =
  {
    [FUSE_LOOKUP]          = { do_lookup,          "LOOKUP"	     },
    [FUSE_FORGET]          = { do_forget,          "FORGET"	     },
    [FUSE_GETATTR]         = { do_getattr,         "GETATTR"         },
    [FUSE_SETATTR]         = { do_setattr,         "SETATTR"         },
    [FUSE_READLINK]        = { do_readlink,        "READLINK"        },
    [FUSE_SYMLINK]         = { do_symlink,         "SYMLINK"         },
    [FUSE_MKNOD]           = { do_mknod,           "MKNOD"	     },
    [FUSE_MKDIR]           = { do_mkdir,           "MKDIR"	     },
    [FUSE_UNLINK]          = { do_unlink,          "UNLINK"	     },
    [FUSE_RMDIR]           = { do_rmdir,           "RMDIR"	     },
    [FUSE_RENAME]          = { do_rename,          "RENAME"	     },
    [FUSE_LINK]            = { do_link,	           "LINK"	     },
    [FUSE_OPEN]            = { do_open,	           "OPEN"	     },
    [FUSE_READ]            = { do_read,	           "READ"	     },
    [FUSE_WRITE]           = { do_write,           "WRITE"	     },
    [FUSE_STATFS]          = { do_statfs,          "STATFS"	     },
    [FUSE_RELEASE]         = { do_release,         "RELEASE"         },
    [FUSE_FSYNC]           = { do_fsync,           "FSYNC"	     },
    [FUSE_SETXATTR]        = { do_setxattr,        "SETXATTR"        },
    [FUSE_GETXATTR]        = { do_getxattr,        "GETXATTR"        },
    [FUSE_LISTXATTR]       = { do_listxattr,       "LISTXATTR"       },
    [FUSE_REMOVEXATTR]     = { do_removexattr,     "REMOVEXATTR"     },
    [FUSE_FLUSH]           = { do_flush,           "FLUSH"	     },
    [FUSE_INIT]            = { do_init,	           "INIT"	     },
    [FUSE_OPENDIR]         = { do_opendir,         "OPENDIR"         },
    [FUSE_READDIR]         = { do_readdir,         "READDIR"         },
    [FUSE_READDIRPLUS]     = { do_readdir_plus,    "READDIR_PLUS"    },
    [FUSE_RELEASEDIR]      = { do_releasedir,      "RELEASEDIR"      },
    [FUSE_FSYNCDIR]        = { do_fsyncdir,        "FSYNCDIR"        },
    [FUSE_GETLK]           = { do_getlk,           "GETLK"	     },
    [FUSE_SETLK]           = { do_setlk,           "SETLK"	     },
    [FUSE_SETLKW]          = { do_setlkw,          "SETLKW"	     },
    [FUSE_ACCESS]          = { do_access,          "ACCESS"	     },
    [FUSE_CREATE]          = { do_create,          "CREATE"	     },
    [FUSE_INTERRUPT]       = { do_interrupt,       "INTERRUPT"       },
    [FUSE_BMAP]            = { do_bmap,	           "BMAP"	     },
    [FUSE_IOCTL]           = { do_ioctl,           "IOCTL"	     },
    [FUSE_POLL]            = { do_poll,            "POLL"	     },
    [FUSE_FALLOCATE]       = { do_fallocate,       "FALLOCATE"       },
    [FUSE_DESTROY]         = { do_destroy,         "DESTROY"         },
    [FUSE_NOTIFY_REPLY]    = { (void *) 1,         "NOTIFY_REPLY"    },
    [FUSE_BATCH_FORGET]    = { do_batch_forget,    "BATCH_FORGET"    },
    [FUSE_COPY_FILE_RANGE] = { do_copy_file_range, "COPY_FILE_RANGE" },
  };

#define FUSE_MAXOP (sizeof(fuse_ll_ops) / sizeof(fuse_ll_ops[0]))

static const char *opname(enum fuse_opcode opcode)
{
  if (opcode >= FUSE_MAXOP || !fuse_ll_ops[opcode].name)
    return "???";
  else
    return fuse_ll_ops[opcode].name;
}

static int fuse_ll_copy_from_pipe(struct fuse_bufvec *dst,
				  struct fuse_bufvec *src)
{
  int res = fuse_buf_copy(dst, src, 0);
  if (res < 0) {
    fprintf(stderr, "fuse: copy from pipe: %s\n", strerror(-res));
    return res;
  }
  if (res < fuse_buf_size(dst)) {
    fprintf(stderr, "fuse: copy from pipe: short read\n");
    return -1;
  }
  return 0;
}

static void fuse_ll_process_buf(void *data, const struct fuse_buf *buf,
				struct fuse_chan *ch)
{
  struct fuse_ll *f = (struct fuse_ll *) data;
  const size_t write_header_size = sizeof(struct fuse_in_header) +
    sizeof(struct fuse_write_in);
  struct fuse_bufvec bufv = { .buf[0] = *buf, .count = 1 };
  struct fuse_bufvec tmpbuf = FUSE_BUFVEC_INIT(write_header_size);
  struct fuse_in_header *in;
  const void *inarg;
  struct fuse_req *req;
  void *mbuf = NULL;
  int err;
  int res;

  if (buf->flags & FUSE_BUF_IS_FD) {
    if (buf->size < tmpbuf.buf[0].size)
      tmpbuf.buf[0].size = buf->size;

    mbuf = xmem_malloc(tmpbuf.buf[0].size);
    if (mbuf == NULL) {
      fprintf(stderr, "fuse: failed to allocate header\n");
      goto clear_pipe;
    }
    tmpbuf.buf[0].mem = mbuf;

    res = fuse_ll_copy_from_pipe(&tmpbuf, &bufv);
    if (res < 0)
      goto clear_pipe;

    in = mbuf;
  } else {
    in = buf->mem;
  }

  if (f->debug) {
    fprintf(stderr,
            "unique: %llu, opcode: %s (%i), nodeid: %lu, insize: %zu, pid: %u\n",
            (unsigned long long) in->unique,
            opname((enum fuse_opcode) in->opcode), in->opcode,
            (unsigned long) in->nodeid, buf->size, in->pid);
  }

  req = fuse_ll_alloc_req(f);
  if (req == NULL) {
    struct fuse_out_header out = {
      .unique = in->unique,
      .error = -ENOMEM,
    };
    struct iovec iov = {
      .iov_base = &out,
      .iov_len = sizeof(struct fuse_out_header),
    };

    fuse_send_msg(f, ch, &iov, 1);
    goto clear_pipe;
  }

  req->unique = in->unique;
  req->ctx.uid = in->uid;
  req->ctx.gid = in->gid;
  req->ctx.pid = in->pid;
  req->ch = ch;

  err = EIO;
  if(!f->got_init)
    {
      enum fuse_opcode expected;

      expected = FUSE_INIT;
      if (in->opcode != expected)
        goto reply_err;
    }
  else if(in->opcode == FUSE_INIT)
    goto reply_err;

  err = EACCES;
  if (f->allow_root                  &&
      in->uid    != f->owner         &&
      in->uid    != 0                &&
      in->opcode != FUSE_INIT        &&
      in->opcode != FUSE_READ        &&
      in->opcode != FUSE_WRITE       &&
      in->opcode != FUSE_FSYNC       &&
      in->opcode != FUSE_RELEASE     &&
      in->opcode != FUSE_READDIR     &&
      in->opcode != FUSE_READDIRPLUS &&
      in->opcode != FUSE_FSYNCDIR    &&
      in->opcode != FUSE_RELEASEDIR  &&
      in->opcode != FUSE_NOTIFY_REPLY)
    goto reply_err;

  err = ENOSYS;
  if (in->opcode >= FUSE_MAXOP || !fuse_ll_ops[in->opcode].func)
    goto reply_err;
  if (in->opcode != FUSE_INTERRUPT) {
    struct fuse_req *intr;
    pthread_mutex_lock(&f->lock);
    intr = check_interrupt(f, req);
    list_add_req(req, &f->list);
    pthread_mutex_unlock(&f->lock);
    if (intr)
      fuse_reply_err(intr, EAGAIN);
  }

  if ((buf->flags & FUSE_BUF_IS_FD) && write_header_size < buf->size &&
      (in->opcode != FUSE_WRITE || !f->op.write_buf) &&
      in->opcode != FUSE_NOTIFY_REPLY) {
    void *newmbuf;

    err = ENOMEM;
    newmbuf = xmem_realloc(mbuf, buf->size);
    if (newmbuf == NULL)
      goto reply_err;
    mbuf = newmbuf;

    tmpbuf = FUSE_BUFVEC_INIT(buf->size - write_header_size);
    tmpbuf.buf[0].mem = mbuf + write_header_size;

    res = fuse_ll_copy_from_pipe(&tmpbuf, &bufv);
    err = -res;
    if (res < 0)
      goto reply_err;

    in = mbuf;
  }

  inarg = (void *) &in[1];
  if (in->opcode == FUSE_WRITE && f->op.write_buf)
    do_write_buf(req, in->nodeid, inarg, buf);
  else if (in->opcode == FUSE_NOTIFY_REPLY)
    do_notify_reply(req, in->nodeid, inarg, buf);
  else
    fuse_ll_ops[in->opcode].func(req, in->nodeid, inarg);

 out_free:
  xmem_free(mbuf);
  return;

 reply_err:
  fuse_reply_err(req, err);
 clear_pipe:
  if (buf->flags & FUSE_BUF_IS_FD)
    fuse_ll_clear_pipe(f);
  goto out_free;
}

static void fuse_ll_process(void *data, const char *buf, size_t len,
			    struct fuse_chan *ch)
{
  struct fuse_buf fbuf = {
    .mem = (void *) buf,
    .size = len,
  };

  fuse_ll_process_buf(data, &fbuf, ch);
}

enum {
  KEY_HELP,
  KEY_VERSION,
};

static const struct fuse_opt fuse_ll_opts[] = {
  { "debug", offsetof(struct fuse_ll, debug), 1 },
  { "-d", offsetof(struct fuse_ll, debug), 1 },
  { "allow_root", offsetof(struct fuse_ll, allow_root), 1 },
  { "max_readahead=%u", offsetof(struct fuse_ll, conn.max_readahead), 0 },
  { "max_background=%u", offsetof(struct fuse_ll, conn.max_background), 0 },
  { "congestion_threshold=%u",
    offsetof(struct fuse_ll, conn.congestion_threshold), 0 },
  { "no_remote_lock", offsetof(struct fuse_ll, no_remote_posix_lock), 1},
  { "no_remote_lock", offsetof(struct fuse_ll, no_remote_flock), 1},
  { "no_remote_flock", offsetof(struct fuse_ll, no_remote_flock), 1},
  { "no_remote_posix_lock", offsetof(struct fuse_ll, no_remote_posix_lock), 1},
  { "splice_write", offsetof(struct fuse_ll, splice_write), 1},
  { "no_splice_write", offsetof(struct fuse_ll, no_splice_write), 1},
  { "splice_move", offsetof(struct fuse_ll, splice_move), 1},
  { "no_splice_move", offsetof(struct fuse_ll, no_splice_move), 1},
  { "splice_read", offsetof(struct fuse_ll, splice_read), 1},
  { "no_splice_read", offsetof(struct fuse_ll, no_splice_read), 1},
  FUSE_OPT_KEY("max_read=", FUSE_OPT_KEY_DISCARD),
  FUSE_OPT_KEY("-h", KEY_HELP),
  FUSE_OPT_KEY("--help", KEY_HELP),
  FUSE_OPT_KEY("-V", KEY_VERSION),
  FUSE_OPT_KEY("--version", KEY_VERSION),
  FUSE_OPT_END
};

static void fuse_ll_version(void)
{
  fprintf(stderr, "using FUSE kernel interface version %i.%i\n",
          FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
}

static void fuse_ll_help(void)
{
  fprintf(stderr,
          "    -o max_readahead=N     set maximum readahead\n"
          "    -o max_background=N    set number of maximum background requests\n"
          "    -o congestion_threshold=N  set kernel's congestion threshold\n"
          "    -o no_remote_lock      disable remote file locking\n"
          "    -o no_remote_flock     disable remote file locking (BSD)\n"
          "    -o no_remote_posix_lock disable remove file locking (POSIX)\n"
          "    -o [no_]splice_write   use splice to write to the fuse device\n"
          "    -o [no_]splice_move    move data while splicing to the fuse device\n"
          "    -o [no_]splice_read    use splice to read from the fuse device\n"
          );
}

static int fuse_ll_opt_proc(void *data, const char *arg, int key,
			    struct fuse_args *outargs)
{
  (void) data; (void) outargs;

  switch (key) {
  case KEY_HELP:
    fuse_ll_help();
    break;

  case KEY_VERSION:
    fuse_ll_version();
    break;

  default:
    fprintf(stderr, "fuse: unknown option `%s'\n", arg);
  }

  return -1;
}

int fuse_lowlevel_is_lib_option(const char *opt)
{
  return fuse_opt_match(fuse_ll_opts, opt);
}

static void fuse_ll_destroy(void *data)
{
  struct fuse_ll *f = (struct fuse_ll *) data;
  struct fuse_ll_pipe *llp;

  if (f->got_init && !f->got_destroy) {
    if (f->op.destroy)
      f->op.destroy(f->userdata);
  }
  llp = pthread_getspecific(f->pipe_key);
  if (llp != NULL)
    fuse_ll_pipe_free(llp);
  pthread_key_delete(f->pipe_key);
  pthread_mutex_destroy(&f->lock);
  xmem_free(f);
}

static void fuse_ll_pipe_destructor(void *data)
{
  struct fuse_ll_pipe *llp = data;
  fuse_ll_pipe_free(llp);
}

#ifdef HAVE_SPLICE
static int fuse_ll_receive_buf(struct fuse_session *se, struct fuse_buf *buf,
			       struct fuse_chan **chp)
{
  struct fuse_chan *ch = *chp;
  struct fuse_ll *f = fuse_session_data(se);
  size_t bufsize = buf->size;
  struct fuse_ll_pipe *llp;
  struct fuse_buf tmpbuf;
  int err;
  int res;

  if (f->conn.proto_minor < 14 || !(f->conn.want & FUSE_CAP_SPLICE_READ))
    goto fallback;

  llp = fuse_ll_get_pipe(f);
  if (llp == NULL)
    goto fallback;

  if (llp->size < bufsize) {
    if (llp->can_grow) {
      res = fcntl(llp->pipe[0], F_SETPIPE_SZ, bufsize);
      if (res == -1) {
        llp->can_grow = 0;
        goto fallback;
      }
      llp->size = res;
    }
    if (llp->size < bufsize)
      goto fallback;
  }

  res = splice(fuse_chan_fd(ch), NULL, llp->pipe[1], NULL, bufsize, 0);
  err = errno;

  if (fuse_session_exited(se))
    return 0;

  if (res == -1) {
    if (err == ENODEV) {
      fuse_session_exit(se);
      return 0;
    }
    if (err != EINTR && err != EAGAIN)
      perror("fuse: splice from device");
    return -err;
  }

  if (res < sizeof(struct fuse_in_header)) {
    fprintf(stderr, "short splice from fuse device\n");
    return -EIO;
  }

  tmpbuf = (struct fuse_buf) {
    .size = res,
    .flags = FUSE_BUF_IS_FD,
    .fd = llp->pipe[0],
  };

  /*
   * Don't bother with zero copy for small requests.
   * fuse_loop_mt() needs to check for FORGET so this more than
   * just an optimization.
   */
  if (res < sizeof(struct fuse_in_header) +
      sizeof(struct fuse_write_in) + pagesize) {
    struct fuse_bufvec src = { .buf[0] = tmpbuf, .count = 1 };
    struct fuse_bufvec dst = { .buf[0] = *buf, .count = 1 };

    res = fuse_buf_copy(&dst, &src, 0);
    if (res < 0) {
      fprintf(stderr, "fuse: copy from pipe: %s\n",
              strerror(-res));
      fuse_ll_clear_pipe(f);
      return res;
    }
    if (res < tmpbuf.size) {
      fprintf(stderr, "fuse: copy from pipe: short read\n");
      fuse_ll_clear_pipe(f);
      return -EIO;
    }
    buf->size = tmpbuf.size;
    return buf->size;
  }

  *buf = tmpbuf;

  return res;

 fallback:
  res = fuse_chan_recv(chp, buf->mem, bufsize);
  if (res <= 0)
    return res;

  buf->size = res;

  return res;
}
#else
static int fuse_ll_receive_buf(struct fuse_session *se, struct fuse_buf *buf,
			       struct fuse_chan **chp)
{
  (void) se;

  int res = fuse_chan_recv(chp, buf->mem, buf->size);
  if (res <= 0)
    return res;

  buf->size = res;

  return res;
}
#endif


/*
 * always call fuse_lowlevel_new_common() internally, to work around a
 * misfeature in the FreeBSD runtime linker, which links the old
 * version of a symbol to internal references.
 */
struct fuse_session *fuse_lowlevel_new_common(struct fuse_args *args,
					      const struct fuse_lowlevel_ops *op,
					      size_t op_size, void *userdata)
{
  int err;
  struct fuse_ll *f;
  struct fuse_session *se;
  struct fuse_session_ops sop = {
    .process = fuse_ll_process,
    .destroy = fuse_ll_destroy,
  };

  if (sizeof(struct fuse_lowlevel_ops) < op_size) {
    fprintf(stderr, "fuse: warning: library too old, some operations may not work\n");
    op_size = sizeof(struct fuse_lowlevel_ops);
  }

  f = (struct fuse_ll *)xmem_calloc(1, sizeof(struct fuse_ll));
  if (f == NULL) {
    fprintf(stderr, "fuse: failed to allocate fuse object\n");
    goto out;
  }

  f->conn.max_write = UINT_MAX;
  f->conn.max_readahead = UINT_MAX;
  list_init_req(&f->list);
  list_init_req(&f->interrupts);
  list_init_nreq(&f->notify_list);
  f->notify_ctr = 1;
  fuse_mutex_init(&f->lock);

  err = pthread_key_create(&f->pipe_key, fuse_ll_pipe_destructor);
  if (err) {
    fprintf(stderr, "fuse: failed to create thread specific key: %s\n",
            strerror(err));
    goto out_free;
  }

  if (fuse_opt_parse(args, f, fuse_ll_opts, fuse_ll_opt_proc) == -1)
    goto out_key_destroy;

  if (f->debug)
    fprintf(stderr, "FUSE library version: %s\n", PACKAGE_VERSION);

  memcpy(&f->op, op, op_size);
  f->owner = getuid();
  f->userdata = userdata;

  se = fuse_session_new(&sop, f);
  if (!se)
    goto out_key_destroy;

  se->receive_buf = fuse_ll_receive_buf;
  se->process_buf = fuse_ll_process_buf;

  return se;

 out_key_destroy:
  pthread_key_delete(f->pipe_key);
 out_free:
  pthread_mutex_destroy(&f->lock);
  xmem_free(f);
 out:
  return NULL;
}

struct fuse_session*
fuse_lowlevel_new(struct fuse_args *args,
                  const struct fuse_lowlevel_ops *op,
                  size_t op_size,
                  void *userdata)
{
  return fuse_lowlevel_new_common(args, op, op_size, userdata);
}