/*

 * unix_io.c --- This is the Unix (well, really POSIX) implementation

 *  of the I/O manager.

 *

 * Implements a one-block write-through cache.

 *

 * Includes support for Windows NT support under Cygwin.

 *

 * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,

 *  2002 by Theodore Ts'o.

 *

 * %Begin-Header%

 * This file may be redistributed under the terms of the GNU Library

 * General Public License, version 2.

 * %End-Header%

 */

#if !defined(__FreeBSD__) && !defined(__NetBSD__) && !defined(__OpenBSD__)

#define _XOPEN_SOURCE 600

#define _DARWIN_C_SOURCE

#ifndef _LARGEFILE_SOURCE

#define _LARGEFILE_SOURCE

#endif

#ifndef _LARGEFILE64_SOURCE

#define _LARGEFILE64_SOURCE

#endif

#ifndef _GNU_SOURCE

#define _GNU_SOURCE

#endif

#endif

#include "config.h"

#include <stdio.h>

#include <string.h>

#if HAVE_UNISTD_H

#include <unistd.h>

#endif

#if HAVE_ERRNO_H

#include <errno.h>

#endif

#include <fcntl.h>

#include <time.h>

#ifdef __linux__

#include <sys/utsname.h>

#endif

#if HAVE_SYS_TYPES_H

#include <sys/types.h>

#endif

#ifdef HAVE_SYS_IOCTL_H

#include <sys/ioctl.h>

#endif

#ifdef HAVE_SYS_MOUNT_H

#include <sys/mount.h>

#endif

#if HAVE_SYS_STAT_H

#include <sys/stat.h>

#endif

#if HAVE_SYS_RESOURCE_H

#include <sys/resource.h>

#endif

#if HAVE_LINUX_FALLOC_H

#include <linux/falloc.h>

#endif

#ifdef HAVE_PTHREAD

#include <pthread.h>

#endif

#if defined(__linux__) && defined(_IO) && !defined(BLKROGET)

#define BLKROGET   _IO(0x12, 94) /* Get read-only status (0 = read_write).  */

#endif

#undef ALIGN_DEBUG

#include "ext2_fs.h"

#include "ext2fs.h"

#include "ext2fsP.h"

/*

 * For checking structure magic numbers...

 */

#define EXT2_CHECK_MAGIC(struct, code) \

    if ((struct)->magic != (code)) return (code)

struct unix_cache {

  char      *buf;

  unsigned long long  block;

  int     access_time;

  unsigned    dirty:1;

  unsigned    in_use:1;

  unsigned    write_err:1;

};

#define CACHE_SIZE 8

#define WRITE_DIRECT_SIZE 4  /* Must be smaller than CACHE_SIZE */

#define READ_DIRECT_SIZE 4  /* Should be smaller than CACHE_SIZE */

struct unix_private_data {

  int magic;

  int dev;

  int flags;

  int align;

  int access_time;

  ext2_loff_t offset;

  struct unix_cache cache[CACHE_SIZE];

  void  *bounce;

  struct struct_io_stats io_stats;

#ifdef HAVE_PTHREAD

  pthread_mutex_t cache_mutex;

  pthread_mutex_t bounce_mutex;

  pthread_mutex_t stats_mutex;

#endif

};

#define IS_ALIGNED(n, align) ((((uintptr_t) n) & \

             ((uintptr_t) ((align)-1))) == 0)

typedef enum lock_kind {

  CACHE_MTX, BOUNCE_MTX, STATS_MTX

} kind_t;

#ifdef HAVE_PTHREAD

static inline pthread_mutex_t *get_mutex(struct unix_private_data *data,

           kind_t kind)

{

  if (data->flags & IO_FLAG_THREADS) {

    switch (kind) {

    case CACHE_MTX:

      return &data->cache_mutex;

    case BOUNCE_MTX:

      return &data->bounce_mutex;

    case STATS_MTX:

      return &data->stats_mutex;

    }

  }

  return NULL;

}

#endif

static inline void mutex_lock(struct unix_private_data *data, kind_t kind)

{

#ifdef HAVE_PTHREAD

  pthread_mutex_t *mtx = get_mutex(data,kind);

  if (mtx)

    pthread_mutex_lock(mtx);

#endif

}

static inline void mutex_unlock(struct unix_private_data *data, kind_t kind)

{

#ifdef HAVE_PTHREAD

  pthread_mutex_t *mtx = get_mutex(data,kind);

  if (mtx)

    pthread_mutex_unlock(mtx);

#endif

}

static errcode_t unix_get_stats(io_channel channel, io_stats *stats)

{

  errcode_t retval = 0;

  struct unix_private_data *data;

  EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);

  data = (struct unix_private_data *) channel->private_data;

  EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);

  if (stats) {

    mutex_lock(data, STATS_MTX);

    *stats = &data->io_stats;

    mutex_unlock(data, STATS_MTX);

  }

  return retval;

}

/*

 * Here are the raw I/O functions

 */

static errcode_t raw_read_blk(io_channel channel,

            struct unix_private_data *data,

            unsigned long long block,

            int count, void *bufv)

{

  errcode_t retval;

  ssize_t   size;

  ext2_loff_t location;

  int   actual = 0;

  unsigned char *buf = bufv;

  ssize_t   really_read = 0;

  unsigned long long aligned_blk;

  int   align_size, offset;

  size = (count < 0) ? -count : (ext2_loff_t) count * channel->block_size;

  mutex_lock(data, STATS_MTX);

  data->io_stats.bytes_read += size;

  mutex_unlock(data, STATS_MTX);

  location = ((ext2_loff_t) block * channel->block_size) + data->offset;

  if (data->flags & IO_FLAG_FORCE_BOUNCE)

    goto bounce_read;

#ifdef HAVE_PREAD64

  /* Try an aligned pread */

  if ((channel->align == 0) ||

      (IS_ALIGNED(buf, channel->align) &&

       IS_ALIGNED(location, channel->align) &&

       IS_ALIGNED(size, channel->align))) {

    actual = pread64(data->dev, buf, size, location);

    if (actual == size)

      return 0;

    actual = 0;

  }

#elif HAVE_PREAD

  /* Try an aligned pread */

  if ((sizeof(off_t) >= sizeof(ext2_loff_t)) &&

      ((channel->align == 0) ||

       (IS_ALIGNED(buf, channel->align) &&

        IS_ALIGNED(location, channel->align) &&

        IS_ALIGNED(size, channel->align)))) {

    actual = pread(data->dev, buf, size, location);

    if (actual == size)

      return 0;

    actual = 0;

  }

#endif /* HAVE_PREAD */

  if ((channel->align == 0) ||

      (IS_ALIGNED(buf, channel->align) &&

       IS_ALIGNED(location, channel->align) &&

       IS_ALIGNED(size, channel->align))) {

    mutex_lock(data, BOUNCE_MTX);

    if (ext2fs_llseek(data->dev, location, SEEK_SET) < 0) {

      retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;

      goto error_unlock;

    }

    actual = read(data->dev, buf, size);

    if (actual != size) {

    short_read:

      if (actual < 0) {

        retval = errno;

        actual = 0;

      } else

        retval = EXT2_ET_SHORT_READ;

      goto error_unlock;

    }

    goto success_unlock;

  }

#ifdef ALIGN_DEBUG

  printf("raw_read_blk: O_DIRECT fallback: %p %lu\n", buf,

         (unsigned long) size);

#endif

  /*

   * The buffer or size which we're trying to read isn't aligned

   * to the O_DIRECT rules, so we need to do this the hard way...

   */

bounce_read:

  if (channel->align == 0)

    channel->align = 1;

  if ((channel->block_size > channel->align) &&

      (channel->block_size % channel->align) == 0)

    align_size = channel->block_size;

  else

    align_size = channel->align;

  aligned_blk = location / align_size;

  offset = location % align_size;

  mutex_lock(data, BOUNCE_MTX);

  if (ext2fs_llseek(data->dev, aligned_blk * align_size, SEEK_SET) < 0) {

    retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;

    goto error_unlock;

  }

  while (size > 0) {

    actual = read(data->dev, data->bounce, align_size);

    if (actual != align_size) {

      actual = really_read;

      buf -= really_read;

      size += really_read;

      goto short_read;

    }

    if ((actual + offset) > align_size)

      actual = align_size - offset;

    if (actual > size)

      actual = size;

    memcpy(buf, (char *)data->bounce + offset, actual);

    really_read += actual;

    size -= actual;

    buf += actual;

    offset = 0;

    aligned_blk++;

  }

success_unlock:

  mutex_unlock(data, BOUNCE_MTX);

  return 0;

error_unlock:

  mutex_unlock(data, BOUNCE_MTX);

  if (actual >= 0 && actual < size)

    memset((char *) buf+actual, 0, size-actual);

  if (channel->read_error)

    retval = (channel->read_error)(channel, block, count, buf,

                 size, actual, retval);

  return retval;

}

#define RAW_WRITE_NO_HANDLER  1

static errcode_t raw_write_blk(io_channel channel,

             struct unix_private_data *data,

             unsigned long long block,

             int count, const void *bufv,

             int flags)

{

  ssize_t   size;

  ext2_loff_t location;

  int   actual = 0;

  errcode_t retval;

  const unsigned char *buf = bufv;

  unsigned long long aligned_blk;

  int   align_size, offset;

  if (count == 1)

    size = channel->block_size;

  else {

    if (count < 0)

      size = -count;

    else

      size = (ext2_loff_t) count * channel->block_size;

  }

  mutex_lock(data, STATS_MTX);

  data->io_stats.bytes_written += size;

  mutex_unlock(data, STATS_MTX);

  location = ((ext2_loff_t) block * channel->block_size) + data->offset;

  if (data->flags & IO_FLAG_FORCE_BOUNCE)

    goto bounce_write;

#ifdef HAVE_PWRITE64

  /* Try an aligned pwrite */

  if ((channel->align == 0) ||

      (IS_ALIGNED(buf, channel->align) &&

       IS_ALIGNED(location, channel->align) &&

       IS_ALIGNED(size, channel->align))) {

    actual = pwrite64(data->dev, buf, size, location);

    if (actual == size)

      return 0;

  }

#elif HAVE_PWRITE

  /* Try an aligned pwrite */

  if ((sizeof(off_t) >= sizeof(ext2_loff_t)) &&

      ((channel->align == 0) ||

       (IS_ALIGNED(buf, channel->align) &&

        IS_ALIGNED(location, channel->align) &&

        IS_ALIGNED(size, channel->align)))) {

    actual = pwrite(data->dev, buf, size, location);

    if (actual == size)

      return 0;

  }

#endif /* HAVE_PWRITE */

  if ((channel->align == 0) ||

      (IS_ALIGNED(buf, channel->align) &&

       IS_ALIGNED(location, channel->align) &&

       IS_ALIGNED(size, channel->align))) {

    mutex_lock(data, BOUNCE_MTX);

    if (ext2fs_llseek(data->dev, location, SEEK_SET) < 0) {

      retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;

      goto error_unlock;

    }

    actual = write(data->dev, buf, size);

    mutex_unlock(data, BOUNCE_MTX);

    if (actual < 0) {

      retval = errno;

      goto error_out;

    }

    if (actual != size) {

    short_write:

      retval = EXT2_ET_SHORT_WRITE;

      goto error_out;

    }

    return 0;

  }

#ifdef ALIGN_DEBUG

  printf("raw_write_blk: O_DIRECT fallback: %p %lu\n", buf,

         (unsigned long) size);

#endif

  /*

   * The buffer or size which we're trying to write isn't aligned

   * to the O_DIRECT rules, so we need to do this the hard way...

   */

bounce_write:

  if (channel->align == 0)

    channel->align = 1;

  if ((channel->block_size > channel->align) &&

      (channel->block_size % channel->align) == 0)

    align_size = channel->block_size;

  else

    align_size = channel->align;

  aligned_blk = location / align_size;

  offset = location % align_size;

  while (size > 0) {

    int actual_w;

    mutex_lock(data, BOUNCE_MTX);

    if (size < align_size || offset) {

      if (ext2fs_llseek(data->dev, aligned_blk * align_size,

            SEEK_SET) < 0) {

        retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;

        goto error_unlock;

      }

      actual = read(data->dev, data->bounce,

              align_size);

      if (actual != align_size) {

        if (actual < 0) {

          retval = errno;

          goto error_unlock;

        }

        memset((char *) data->bounce + actual, 0,

               align_size - actual);

      }

    }

    actual = size;

    if ((actual + offset) > align_size)

      actual = align_size - offset;

    if (actual > size)

      actual = size;

    memcpy(((char *)data->bounce) + offset, buf, actual);

    if (ext2fs_llseek(data->dev, aligned_blk * align_size, SEEK_SET) < 0) {

      retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;

      goto error_unlock;

    }

    actual_w = write(data->dev, data->bounce, align_size);

    mutex_unlock(data, BOUNCE_MTX);

    if (actual_w < 0) {

      retval = errno;

      goto error_out;

    }

    if (actual_w != align_size)

      goto short_write;

    size -= actual;

    buf += actual;

    location += actual;

    aligned_blk++;

    offset = 0;

  }

  return 0;

error_unlock:

  mutex_unlock(data, BOUNCE_MTX);

error_out:

  if (((flags & RAW_WRITE_NO_HANDLER) == 0) && channel->write_error)

    retval = (channel->write_error)(channel, block, count, buf,

            size, actual, retval);

  return retval;

}

/*

 * Here we implement the cache functions

 */

/* Allocate the cache buffers */

static errcode_t alloc_cache(io_channel channel,

           struct unix_private_data *data)

{

  errcode_t   retval;

  struct unix_cache *cache;

  int     i;

  data->access_time = 0;

  for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {

    cache->block = 0;

    cache->access_time = 0;

    cache->dirty = 0;

    cache->in_use = 0;

    if (cache->buf)

      ext2fs_free_mem(&cache->buf);

    retval = io_channel_alloc_buf(channel, 0, &cache->buf);

    if (retval)

      return retval;

  }

  if (channel->align || data->flags & IO_FLAG_FORCE_BOUNCE) {

    if (data->bounce)

      ext2fs_free_mem(&data->bounce);

    retval = io_channel_alloc_buf(channel, 0, &data->bounce);

  }

  return retval;

}

/* Free the cache buffers */

static void free_cache(struct unix_private_data *data)

{

  struct unix_cache *cache;

  int     i;

  data->access_time = 0;

  for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {

    cache->block = 0;

    cache->access_time = 0;

    cache->dirty = 0;

    cache->in_use = 0;

    if (cache->buf)

      ext2fs_free_mem(&cache->buf);

  }

  if (data->bounce)

    ext2fs_free_mem(&data->bounce);

}

#ifndef NO_IO_CACHE

/*

 * Try to find a block in the cache.  If the block is not found, and

 * eldest is a non-zero pointer, then fill in eldest with the cache

 * entry to that should be reused.

 */

static struct unix_cache *find_cached_block(struct unix_private_data *data,

              unsigned long long block,

              struct unix_cache **eldest)

{

  struct unix_cache *cache, *unused_cache, *oldest_cache;

  int     i;

  unused_cache = oldest_cache = 0;

  for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {

    if (!cache->in_use) {

      if (!unused_cache)

        unused_cache = cache;

      continue;

    }

    if (cache->block == block) {

      cache->access_time = ++data->access_time;

      return cache;

    }

    if (!oldest_cache ||

        (cache->access_time < oldest_cache->access_time))

      oldest_cache = cache;

  }

  if (eldest)

    *eldest = (unused_cache) ? unused_cache : oldest_cache;

  return 0;

}

/*

 * Reuse a particular cache entry for another block.

 */

static errcode_t reuse_cache(io_channel channel,

    struct unix_private_data *data, struct unix_cache *cache,

    unsigned long long block)

{

  if (cache->dirty && cache->in_use) {

    errcode_t retval;

    retval = raw_write_blk(channel, data, cache->block, 1,

               cache->buf, RAW_WRITE_NO_HANDLER);

    if (retval) {

      cache->write_err = 1;

      return retval;

    }

  }

  cache->in_use = 1;

  cache->dirty = 0;

  cache->write_err = 0;

  cache->block = block;

  cache->access_time = ++data->access_time;

  return 0;

}

#define FLUSH_INVALIDATE  0x01

#define FLUSH_NOLOCK    0x02

/*

 * Flush all of the blocks in the cache

 */

static errcode_t flush_cached_blocks(io_channel channel,

             struct unix_private_data *data,

             int flags)

{

  struct unix_cache *cache;

  errcode_t   retval, retval2 = 0;

  int     i;

  int     errors_found = 0;

  if ((flags & FLUSH_NOLOCK) == 0)

    mutex_lock(data, CACHE_MTX);

  for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {

    if (!cache->in_use || !cache->dirty)

      continue;

    retval = raw_write_blk(channel, data,

               cache->block, 1, cache->buf,

               RAW_WRITE_NO_HANDLER);

    if (retval) {

      cache->write_err = 1;

      errors_found = 1;

      retval2 = retval;

    } else {

      cache->dirty = 0;

      cache->write_err = 0;

      if (flags & FLUSH_INVALIDATE)

        cache->in_use = 0;

    }

  }

  if ((flags & FLUSH_NOLOCK) == 0)

    mutex_unlock(data, CACHE_MTX);

retry:

  while (errors_found) {

    if ((flags & FLUSH_NOLOCK) == 0)

      mutex_lock(data, CACHE_MTX);

    errors_found = 0;

    for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {

      if (!cache->in_use || !cache->write_err)

        continue;

      errors_found = 1;

      if (cache->write_err && channel->write_error) {

        char *err_buf = NULL;

        unsigned long long err_block = cache->block;

        cache->dirty = 0;

        cache->in_use = 0;

        cache->write_err = 0;

        if (io_channel_alloc_buf(channel, 0,

               &err_buf))

          err_buf = NULL;

        else

          memcpy(err_buf, cache->buf,

                 channel->block_size);

        mutex_unlock(data, CACHE_MTX);

        (channel->write_error)(channel, err_block,

          1, err_buf, channel->block_size, -1,

          retval2);

        if (err_buf)

          ext2fs_free_mem(&err_buf);

        goto retry;

      } else

        cache->write_err = 0;

    }

    if ((flags & FLUSH_NOLOCK) == 0)

      mutex_unlock(data, CACHE_MTX);

  }

  return retval2;

}

#endif /* NO_IO_CACHE */

#ifdef __linux__

#ifndef BLKDISCARDZEROES

#define BLKDISCARDZEROES _IO(0x12,124)

#endif

#endif

int ext2fs_open_file(const char *pathname, int flags, mode_t mode)

{

  if (mode)

#if defined(HAVE_OPEN64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)

    return open64(pathname, flags, mode);

  else

    return open64(pathname, flags);

#else

    return open(pathname, flags, mode);

  else

    return open(pathname, flags);

#endif

}

int ext2fs_stat(const char *path, ext2fs_struct_stat *buf)

{

#if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)

  return stat64(path, buf);

#else

  return stat(path, buf);

#endif

}

int ext2fs_fstat(int fd, ext2fs_struct_stat *buf)

{

#if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)

  return fstat64(fd, buf);

#else

  return fstat(fd, buf);

#endif

}

static errcode_t unix_open_channel(const char *name, int fd,

           int flags, io_channel *channel,

           io_manager io_mgr)

{

  io_channel  io = NULL;

  struct unix_private_data *data = NULL;

  errcode_t retval;

  ext2fs_struct_stat st;

#ifdef __linux__

  struct    utsname ut;

#endif

  if (ext2fs_safe_getenv("UNIX_IO_FORCE_BOUNCE"))

    flags |= IO_FLAG_FORCE_BOUNCE;

#ifdef __linux__

  /*

   * We need to make sure any previous errors in the block

   * device are thrown away, sigh.

   */

  (void) fsync(fd);

#endif

  retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);

  if (retval)

    goto cleanup;

  memset(io, 0, sizeof(struct struct_io_channel));

  io->magic = EXT2_ET_MAGIC_IO_CHANNEL;

  retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data);

  if (retval)

    goto cleanup;

  io->manager = io_mgr;

  retval = ext2fs_get_mem(strlen(name)+1, &io->name);

  if (retval)

    goto cleanup;

  strcpy(io->name, name);

  io->private_data = data;

  io->block_size = 1024;

  io->read_error = 0;

  io->write_error = 0;

  io->refcount = 1;

  io->flags = 0;

  if (ext2fs_safe_getenv("UNIX_IO_NOZEROOUT"))

    io->flags |= CHANNEL_FLAGS_NOZEROOUT;

  memset(data, 0, sizeof(struct unix_private_data));

  data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL;

  data->io_stats.num_fields = 2;

  data->flags = flags;

  data->dev = fd;

#if defined(O_DIRECT)

  if (flags & IO_FLAG_DIRECT_IO)

    io->align = ext2fs_get_dio_alignment(data->dev);

#elif defined(F_NOCACHE)

  if (flags & IO_FLAG_DIRECT_IO)

    io->align = 4096;

#endif

  /*

   * If the device is really a block device, then set the

   * appropriate flag, otherwise we can set DISCARD_ZEROES flag

   * because we are going to use punch hole instead of discard

   * and if it succeed, subsequent read from sparse area returns

   * zero.

   */

  if (ext2fs_fstat(data->dev, &st) == 0) {

    if (ext2fsP_is_disk_device(st.st_mode)) {

#ifdef BLKDISCARDZEROES

      int zeroes = 0;

      if (ioctl(data->dev, BLKDISCARDZEROES, &zeroes) == 0 &&

          zeroes)

        io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES;

#endif

      io->flags |= CHANNEL_FLAGS_BLOCK_DEVICE;

    } else {

      io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES;

    }

  }

#if defined(__CYGWIN__)

  /*

   * Some operating systems require that the buffers be aligned,

   * regardless of O_DIRECT

   */

  if (!io->align)

    io->align = 512;

#endif

#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)

  if (io->flags & CHANNEL_FLAGS_BLOCK_DEVICE) {

    int dio_align = ext2fs_get_dio_alignment(fd);

    if (io->align < dio_align)

      io->align = dio_align;

  }

#endif

  if ((retval = alloc_cache(io, data)))

    goto cleanup;

#ifdef BLKROGET

  if (flags & IO_FLAG_RW) {

    int error;

    int readonly = 0;

    /* Is the block device actually writable? */

    error = ioctl(data->dev, BLKROGET, &readonly);

    if (!error && readonly) {

      retval = EPERM;

      goto cleanup;

    }

  }

#endif

#ifdef __linux__

#undef RLIM_INFINITY

#if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4)))

#define RLIM_INFINITY ((unsigned long)(~0UL>>1))

#else

#define RLIM_INFINITY  (~0UL)

#endif

  /*

   * Work around a bug in 2.4.10-2.4.18 kernels where writes to

   * block devices are wrongly getting hit by the filesize

   * limit.  This workaround isn't perfect, since it won't work

   * if glibc wasn't built against 2.2 header files.  (Sigh.)

   *

   */

  if ((flags & IO_FLAG_RW) &&

      (uname(&ut) == 0) &&

      ((ut.release[0] == '2') && (ut.release[1] == '.') &&

       (ut.release[2] == '4') && (ut.release[3] == '.') &&

       (ut.release[4] == '1') && (ut.release[5] >= '0') &&

       (ut.release[5] < '8')) &&

      (ext2fs_fstat(data->dev, &st) == 0) &&

      (ext2fsP_is_disk_device(st.st_mode))) {

    struct rlimit rlim;

    rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY;

    setrlimit(RLIMIT_FSIZE, &rlim);

    getrlimit(RLIMIT_FSIZE, &rlim);

    if (((unsigned long) rlim.rlim_cur) <

        ((unsigned long) rlim.rlim_max)) {

      rlim.rlim_cur = rlim.rlim_max;

      setrlimit(RLIMIT_FSIZE, &rlim);

    }

  }

#endif

#ifdef HAVE_PTHREAD

  if (flags & IO_FLAG_THREADS) {

    io->flags |= CHANNEL_FLAGS_THREADS;

    retval = pthread_mutex_init(&data->cache_mutex, NULL);

    if (retval)

      goto cleanup;

    retval = pthread_mutex_init(&data->bounce_mutex, NULL);

    if (retval) {

      pthread_mutex_destroy(&data->cache_mutex);

      goto cleanup;

    }

    retval = pthread_mutex_init(&data->stats_mutex, NULL);

    if (retval) {

      pthread_mutex_destroy(&data->cache_mutex);

      pthread_mutex_destroy(&data->bounce_mutex);

      goto cleanup;

    }

  }

#endif

  *channel = io;

  return 0;

cleanup:

  if (data) {

    if (data->dev >= 0)

      close(data->dev);

    free_cache(data);

    ext2fs_free_mem(&data);

  }

  if (io) {

    if (io->name) {

      ext2fs_free_mem(&io->name);

    }

    ext2fs_free_mem(&io);

  }

  return retval;

}

static errcode_t unixfd_open(const char *str_fd, int flags,

           io_channel *channel)

{

  int fd;

  int fd_flags;

  fd = atoi(str_fd);

#if defined(HAVE_FCNTL)

  fd_flags = fcntl(fd, F_GETFD);

  if (fd_flags == -1)

    return EBADF;

  flags = 0;

  if (fd_flags & O_RDWR)

    flags |= IO_FLAG_RW;

  if (fd_flags & O_EXCL)

    flags |= IO_FLAG_EXCLUSIVE;

#if defined(O_DIRECT)

  if (fd_flags & O_DIRECT)

    flags |= IO_FLAG_DIRECT_IO;

#endif

#endif  /* HAVE_FCNTL */

  return unix_open_channel(str_fd, fd, flags, channel, unixfd_io_manager);

}

static errcode_t unix_open(const char *name, int flags,

         io_channel *channel)

{

  int fd = -1;

  int open_flags;

  if (name == 0)

    return EXT2_ET_BAD_DEVICE_NAME;

  open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY;

  if (flags & IO_FLAG_EXCLUSIVE)

    open_flags |= O_EXCL;

#if defined(O_DIRECT)

  if (flags & IO_FLAG_DIRECT_IO)

    open_flags |= O_DIRECT;

#endif

  fd = ext2fs_open_file(name, open_flags, 0);

  if (fd < 0)

    return errno;

#if defined(F_NOCACHE) && !defined(IO_DIRECT)

  if (flags & IO_FLAG_DIRECT_IO) {

    if (fcntl(fd, F_NOCACHE, 1) < 0)

      return errno;

  }

#endif

  return unix_open_channel(name, fd, flags, channel, unix_io_manager);

}

static errcode_t unix_close(io_channel channel)

{

  struct unix_private_data *data;

  errcode_t retval = 0;

  EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);

  data = (struct unix_private_data *) channel->private_data;

  EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);

  if (--channel->refcount > 0)

    return 0;

#ifndef NO_IO_CACHE

  retval = flush_cached_blocks(channel, data, 0);

#endif

  if (close(data->dev) < 0)

    retval = errno;

  free_cache(data);

#ifdef HAVE_PTHREAD

  if (data->flags & IO_FLAG_THREADS) {