[821] | 1 | /*
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| 2 | * unix_io.c --- This is the Unix (well, really POSIX) implementation
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| 3 | * of the I/O manager.
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| 4 | *
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| 5 | * Implements a one-block write-through cache.
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| 6 | *
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| 7 | * Includes support for Windows NT support under Cygwin.
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| 8 | *
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| 9 | * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
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| 10 | * 2002 by Theodore Ts'o.
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| 11 | *
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| 12 | * %Begin-Header%
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| 13 | * This file may be redistributed under the terms of the GNU Public
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| 14 | * License.
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| 15 | * %End-Header%
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| 16 | */
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| 17 |
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| 18 | #include <stdio.h>
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| 19 | #include <string.h>
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| 20 | #if HAVE_UNISTD_H
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| 21 | #include <unistd.h>
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| 22 | #endif
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| 23 | #if HAVE_ERRNO_H
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| 24 | #include <errno.h>
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| 25 | #endif
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| 26 | #include <fcntl.h>
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| 27 | #include <time.h>
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| 28 | #ifdef __linux__
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| 29 | #include <sys/utsname.h>
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| 30 | #endif
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| 31 | #if HAVE_SYS_STAT_H
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| 32 | #include <sys/stat.h>
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| 33 | #endif
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| 34 | #if HAVE_SYS_TYPES_H
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| 35 | #include <sys/types.h>
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| 36 | #endif
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| 37 | #include <sys/resource.h>
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| 38 |
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| 39 | #include "ext2_fs.h"
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| 40 | #include "ext2fs.h"
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| 41 |
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| 42 | /*
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| 43 | * For checking structure magic numbers...
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| 44 | */
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| 45 |
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| 46 | #define EXT2_CHECK_MAGIC(struct, code) \
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| 47 | if ((struct)->magic != (code)) return (code)
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| 48 |
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| 49 | struct unix_cache {
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| 50 | char *buf;
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| 51 | unsigned long block;
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| 52 | int access_time;
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| 53 | unsigned dirty:1;
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| 54 | unsigned in_use:1;
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| 55 | };
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| 56 |
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| 57 | #define CACHE_SIZE 8
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| 58 | #define WRITE_DIRECT_SIZE 4 /* Must be smaller than CACHE_SIZE */
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| 59 | #define READ_DIRECT_SIZE 4 /* Should be smaller than CACHE_SIZE */
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| 60 |
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| 61 | struct unix_private_data {
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| 62 | int magic;
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| 63 | int dev;
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| 64 | int flags;
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| 65 | int access_time;
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| 66 | ext2_loff_t offset;
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| 67 | struct unix_cache cache[CACHE_SIZE];
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| 68 | };
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| 69 |
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| 70 | static errcode_t unix_open(const char *name, int flags, io_channel *channel);
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| 71 | static errcode_t unix_close(io_channel channel);
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| 72 | static errcode_t unix_set_blksize(io_channel channel, int blksize);
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| 73 | static errcode_t unix_read_blk(io_channel channel, unsigned long block,
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| 74 | int count, void *data);
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| 75 | static errcode_t unix_write_blk(io_channel channel, unsigned long block,
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| 76 | int count, const void *data);
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| 77 | static errcode_t unix_flush(io_channel channel);
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| 78 | static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
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| 79 | int size, const void *data);
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| 80 | static errcode_t unix_set_option(io_channel channel, const char *option,
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| 81 | const char *arg);
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| 82 |
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| 83 | static void reuse_cache(io_channel channel, struct unix_private_data *data,
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| 84 | struct unix_cache *cache, unsigned long block);
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| 85 |
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| 86 | /* __FreeBSD_kernel__ is defined by GNU/kFreeBSD - the FreeBSD kernel
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| 87 | * does not know buffered block devices - everything is raw. */
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| 88 | #if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
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| 89 | #define NEED_BOUNCE_BUFFER
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| 90 | #else
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| 91 | #undef NEED_BOUNCE_BUFFER
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| 92 | #endif
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| 93 |
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| 94 | static struct struct_io_manager struct_unix_manager = {
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| 95 | EXT2_ET_MAGIC_IO_MANAGER,
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| 96 | "Unix I/O Manager",
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| 97 | unix_open,
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| 98 | unix_close,
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| 99 | unix_set_blksize,
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| 100 | unix_read_blk,
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| 101 | unix_write_blk,
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| 102 | unix_flush,
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| 103 | #ifdef NEED_BOUNCE_BUFFER
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| 104 | 0,
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| 105 | #else
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| 106 | unix_write_byte,
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| 107 | #endif
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| 108 | unix_set_option
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| 109 | };
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| 110 |
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| 111 | io_manager unix_io_manager = &struct_unix_manager;
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| 112 |
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| 113 | /*
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| 114 | * Here are the raw I/O functions
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| 115 | */
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| 116 | #ifndef NEED_BOUNCE_BUFFER
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| 117 | static errcode_t raw_read_blk(io_channel channel,
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| 118 | struct unix_private_data *data,
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| 119 | unsigned long block,
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| 120 | int count, void *buf)
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| 121 | {
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| 122 | errcode_t retval;
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| 123 | ssize_t size;
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| 124 | ext2_loff_t location;
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| 125 | int actual = 0;
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| 126 |
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| 127 | size = (count < 0) ? -count : count * channel->block_size;
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| 128 | location = ((ext2_loff_t) block * channel->block_size) + data->offset;
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| 129 | if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
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| 130 | retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
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| 131 | goto error_out;
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| 132 | }
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| 133 | actual = read(data->dev, buf, size);
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| 134 | if (actual != size) {
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| 135 | if (actual < 0)
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| 136 | actual = 0;
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| 137 | retval = EXT2_ET_SHORT_READ;
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| 138 | goto error_out;
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| 139 | }
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| 140 | return 0;
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| 141 |
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| 142 | error_out:
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| 143 | memset((char *) buf+actual, 0, size-actual);
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| 144 | if (channel->read_error)
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| 145 | retval = (channel->read_error)(channel, block, count, buf,
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| 146 | size, actual, retval);
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| 147 | return retval;
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| 148 | }
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| 149 | #else /* NEED_BOUNCE_BUFFER */
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| 150 | /*
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| 151 | * Windows and FreeBSD block devices only allow sector alignment IO in offset and size
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| 152 | */
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| 153 | static errcode_t raw_read_blk(io_channel channel,
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| 154 | struct unix_private_data *data,
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| 155 | unsigned long block,
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| 156 | int count, void *buf)
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| 157 | {
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| 158 | errcode_t retval;
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| 159 | size_t size, alignsize, fragment;
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| 160 | ext2_loff_t location;
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| 161 | int total = 0, actual;
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| 162 | #define BLOCKALIGN 512
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| 163 | char sector[BLOCKALIGN];
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| 164 |
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| 165 | size = (count < 0) ? -count : count * channel->block_size;
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| 166 | location = ((ext2_loff_t) block * channel->block_size) + data->offset;
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| 167 | #ifdef DEBUG
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| 168 | printf("count=%d, size=%d, block=%d, blk_size=%d, location=%lx\n",
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| 169 | count, size, block, channel->block_size, location);
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| 170 | #endif
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| 171 | if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
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| 172 | retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
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| 173 | goto error_out;
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| 174 | }
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| 175 | fragment = size % BLOCKALIGN;
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| 176 | alignsize = size - fragment;
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| 177 | if (alignsize) {
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| 178 | actual = read(data->dev, buf, alignsize);
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| 179 | if (actual != alignsize)
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| 180 | goto short_read;
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| 181 | }
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| 182 | if (fragment) {
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| 183 | actual = read(data->dev, sector, BLOCKALIGN);
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| 184 | if (actual != BLOCKALIGN)
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| 185 | goto short_read;
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| 186 | memcpy(buf+alignsize, sector, fragment);
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| 187 | }
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| 188 | return 0;
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| 189 |
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| 190 | short_read:
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| 191 | if (actual>0)
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| 192 | total += actual;
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| 193 | retval = EXT2_ET_SHORT_READ;
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| 194 |
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| 195 | error_out:
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| 196 | memset((char *) buf+total, 0, size-actual);
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| 197 | if (channel->read_error)
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| 198 | retval = (channel->read_error)(channel, block, count, buf,
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| 199 | size, actual, retval);
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| 200 | return retval;
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| 201 | }
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| 202 | #endif
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| 203 |
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| 204 | static errcode_t raw_write_blk(io_channel channel,
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| 205 | struct unix_private_data *data,
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| 206 | unsigned long block,
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| 207 | int count, const void *buf)
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| 208 | {
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| 209 | ssize_t size;
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| 210 | ext2_loff_t location;
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| 211 | int actual = 0;
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| 212 | errcode_t retval;
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| 213 |
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| 214 | if (count == 1)
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| 215 | size = channel->block_size;
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| 216 | else {
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| 217 | if (count < 0)
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| 218 | size = -count;
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| 219 | else
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| 220 | size = count * channel->block_size;
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| 221 | }
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| 222 |
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| 223 | location = ((ext2_loff_t) block * channel->block_size) + data->offset;
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| 224 | if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
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| 225 | retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
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| 226 | goto error_out;
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| 227 | }
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| 228 |
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| 229 | actual = write(data->dev, buf, size);
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| 230 | if (actual != size) {
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| 231 | retval = EXT2_ET_SHORT_WRITE;
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| 232 | goto error_out;
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| 233 | }
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| 234 | return 0;
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| 235 |
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| 236 | error_out:
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| 237 | if (channel->write_error)
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| 238 | retval = (channel->write_error)(channel, block, count, buf,
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| 239 | size, actual, retval);
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| 240 | return retval;
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| 241 | }
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| 242 |
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| 243 |
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| 244 | /*
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| 245 | * Here we implement the cache functions
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| 246 | */
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| 247 |
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| 248 | /* Allocate the cache buffers */
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| 249 | static errcode_t alloc_cache(io_channel channel,
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| 250 | struct unix_private_data *data)
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| 251 | {
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| 252 | errcode_t retval;
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| 253 | struct unix_cache *cache;
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| 254 | int i;
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| 255 |
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| 256 | data->access_time = 0;
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| 257 | for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
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| 258 | cache->block = 0;
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| 259 | cache->access_time = 0;
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| 260 | cache->dirty = 0;
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| 261 | cache->in_use = 0;
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| 262 | if ((retval = ext2fs_get_mem(channel->block_size,
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| 263 | &cache->buf)))
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| 264 | return retval;
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| 265 | }
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| 266 | return 0;
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| 267 | }
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| 268 |
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| 269 | /* Free the cache buffers */
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| 270 | static void free_cache(struct unix_private_data *data)
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| 271 | {
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| 272 | struct unix_cache *cache;
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| 273 | int i;
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| 274 |
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| 275 | data->access_time = 0;
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| 276 | for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
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| 277 | cache->block = 0;
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| 278 | cache->access_time = 0;
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| 279 | cache->dirty = 0;
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| 280 | cache->in_use = 0;
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| 281 | ext2fs_free_mem(&cache->buf);
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| 282 | cache->buf = 0;
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| 283 | }
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| 284 | }
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| 285 |
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| 286 | #ifndef NO_IO_CACHE
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| 287 | /*
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| 288 | * Try to find a block in the cache. If the block is not found, and
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| 289 | * eldest is a non-zero pointer, then fill in eldest with the cache
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| 290 | * entry to that should be reused.
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| 291 | */
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| 292 | static struct unix_cache *find_cached_block(struct unix_private_data *data,
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| 293 | unsigned long block,
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| 294 | struct unix_cache **eldest)
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| 295 | {
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| 296 | struct unix_cache *cache, *unused_cache, *oldest_cache;
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| 297 | int i;
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| 298 |
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| 299 | unused_cache = oldest_cache = 0;
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| 300 | for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
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| 301 | if (!cache->in_use) {
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| 302 | if (!unused_cache)
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| 303 | unused_cache = cache;
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| 304 | continue;
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| 305 | }
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| 306 | if (cache->block == block) {
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| 307 | cache->access_time = ++data->access_time;
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| 308 | return cache;
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| 309 | }
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| 310 | if (!oldest_cache ||
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| 311 | (cache->access_time < oldest_cache->access_time))
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| 312 | oldest_cache = cache;
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| 313 | }
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| 314 | if (eldest)
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| 315 | *eldest = (unused_cache) ? unused_cache : oldest_cache;
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| 316 | return 0;
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| 317 | }
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| 318 |
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| 319 | /*
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| 320 | * Reuse a particular cache entry for another block.
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| 321 | */
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| 322 | static void reuse_cache(io_channel channel, struct unix_private_data *data,
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| 323 | struct unix_cache *cache, unsigned long block)
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| 324 | {
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| 325 | if (cache->dirty && cache->in_use)
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| 326 | raw_write_blk(channel, data, cache->block, 1, cache->buf);
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| 327 |
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| 328 | cache->in_use = 1;
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| 329 | cache->dirty = 0;
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| 330 | cache->block = block;
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| 331 | cache->access_time = ++data->access_time;
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| 332 | }
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| 333 |
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| 334 | /*
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| 335 | * Flush all of the blocks in the cache
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| 336 | */
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| 337 | static errcode_t flush_cached_blocks(io_channel channel,
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| 338 | struct unix_private_data *data,
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| 339 | int invalidate)
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| 340 |
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| 341 | {
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| 342 | struct unix_cache *cache;
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| 343 | errcode_t retval, retval2;
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| 344 | int i;
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| 345 |
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| 346 | retval2 = 0;
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| 347 | for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
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| 348 | if (!cache->in_use)
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| 349 | continue;
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| 350 |
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| 351 | if (invalidate)
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| 352 | cache->in_use = 0;
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| 353 |
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| 354 | if (!cache->dirty)
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| 355 | continue;
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| 356 |
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| 357 | retval = raw_write_blk(channel, data,
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| 358 | cache->block, 1, cache->buf);
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| 359 | if (retval)
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| 360 | retval2 = retval;
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| 361 | else
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| 362 | cache->dirty = 0;
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| 363 | }
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| 364 | return retval2;
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| 365 | }
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| 366 | #endif /* NO_IO_CACHE */
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| 367 |
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| 368 | static errcode_t unix_open(const char *name, int flags, io_channel *channel)
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| 369 | {
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| 370 | io_channel io = NULL;
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| 371 | struct unix_private_data *data = NULL;
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| 372 | errcode_t retval;
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| 373 | int open_flags;
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| 374 | struct stat st;
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| 375 | #ifdef __linux__
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| 376 | struct utsname ut;
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| 377 | #endif
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| 378 |
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| 379 | if (name == 0)
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| 380 | return EXT2_ET_BAD_DEVICE_NAME;
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| 381 | retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
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| 382 | if (retval)
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| 383 | return retval;
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| 384 | memset(io, 0, sizeof(struct struct_io_channel));
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| 385 | io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
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| 386 | retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data);
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| 387 | if (retval)
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| 388 | goto cleanup;
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| 389 |
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| 390 | io->manager = unix_io_manager;
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| 391 | retval = ext2fs_get_mem(strlen(name)+1, &io->name);
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| 392 | if (retval)
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| 393 | goto cleanup;
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| 394 |
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| 395 | strcpy(io->name, name);
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| 396 | io->private_data = data;
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| 397 | io->block_size = 1024;
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| 398 | io->read_error = 0;
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| 399 | io->write_error = 0;
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| 400 | io->refcount = 1;
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| 401 |
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| 402 | memset(data, 0, sizeof(struct unix_private_data));
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| 403 | data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL;
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| 404 |
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| 405 | if ((retval = alloc_cache(io, data)))
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| 406 | goto cleanup;
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| 407 |
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| 408 | open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY;
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| 409 | #ifdef CONFIG_LFS
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| 410 | data->dev = open64(io->name, open_flags);
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| 411 | #else
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| 412 | data->dev = open(io->name, open_flags);
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| 413 | #endif
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| 414 | if (data->dev < 0) {
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| 415 | retval = errno;
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| 416 | goto cleanup;
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| 417 | }
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| 418 |
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| 419 | #ifdef __linux__
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| 420 | #undef RLIM_INFINITY
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| 421 | #if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4)))
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| 422 | #define RLIM_INFINITY ((unsigned long)(~0UL>>1))
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| 423 | #else
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| 424 | #define RLIM_INFINITY (~0UL)
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| 425 | #endif
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| 426 | /*
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| 427 | * Work around a bug in 2.4.10-2.4.18 kernels where writes to
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| 428 | * block devices are wrongly getting hit by the filesize
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| 429 | * limit. This workaround isn't perfect, since it won't work
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| 430 | * if glibc wasn't built against 2.2 header files. (Sigh.)
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| 431 | *
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| 432 | */
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| 433 | if ((flags & IO_FLAG_RW) &&
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| 434 | (uname(&ut) == 0) &&
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| 435 | ((ut.release[0] == '2') && (ut.release[1] == '.') &&
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| 436 | (ut.release[2] == '4') && (ut.release[3] == '.') &&
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| 437 | (ut.release[4] == '1') && (ut.release[5] >= '0') &&
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| 438 | (ut.release[5] < '8')) &&
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| 439 | (fstat(data->dev, &st) == 0) &&
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| 440 | (S_ISBLK(st.st_mode))) {
|
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| 441 | struct rlimit rlim;
|
---|
| 442 |
|
---|
| 443 | rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY;
|
---|
| 444 | setrlimit(RLIMIT_FSIZE, &rlim);
|
---|
| 445 | getrlimit(RLIMIT_FSIZE, &rlim);
|
---|
| 446 | if (((unsigned long) rlim.rlim_cur) <
|
---|
| 447 | ((unsigned long) rlim.rlim_max)) {
|
---|
| 448 | rlim.rlim_cur = rlim.rlim_max;
|
---|
| 449 | setrlimit(RLIMIT_FSIZE, &rlim);
|
---|
| 450 | }
|
---|
| 451 | }
|
---|
| 452 | #endif
|
---|
| 453 | *channel = io;
|
---|
| 454 | return 0;
|
---|
| 455 |
|
---|
| 456 | cleanup:
|
---|
| 457 | if (data) {
|
---|
| 458 | free_cache(data);
|
---|
| 459 | ext2fs_free_mem(&data);
|
---|
| 460 | }
|
---|
| 461 | ext2fs_free_mem(&io);
|
---|
| 462 | return retval;
|
---|
| 463 | }
|
---|
| 464 |
|
---|
| 465 | static errcode_t unix_close(io_channel channel)
|
---|
| 466 | {
|
---|
| 467 | struct unix_private_data *data;
|
---|
| 468 | errcode_t retval = 0;
|
---|
| 469 |
|
---|
| 470 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
| 471 | data = (struct unix_private_data *) channel->private_data;
|
---|
| 472 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
| 473 |
|
---|
| 474 | if (--channel->refcount > 0)
|
---|
| 475 | return 0;
|
---|
| 476 |
|
---|
| 477 | #ifndef NO_IO_CACHE
|
---|
| 478 | retval = flush_cached_blocks(channel, data, 0);
|
---|
| 479 | #endif
|
---|
| 480 |
|
---|
| 481 | if (close(data->dev) < 0)
|
---|
| 482 | retval = errno;
|
---|
| 483 | free_cache(data);
|
---|
| 484 |
|
---|
| 485 | ext2fs_free_mem(&channel->private_data);
|
---|
| 486 | ext2fs_free_mem(&channel->name);
|
---|
| 487 | ext2fs_free_mem(&channel);
|
---|
| 488 | return retval;
|
---|
| 489 | }
|
---|
| 490 |
|
---|
| 491 | static errcode_t unix_set_blksize(io_channel channel, int blksize)
|
---|
| 492 | {
|
---|
| 493 | struct unix_private_data *data;
|
---|
| 494 | errcode_t retval;
|
---|
| 495 |
|
---|
| 496 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
| 497 | data = (struct unix_private_data *) channel->private_data;
|
---|
| 498 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
| 499 |
|
---|
| 500 | if (channel->block_size != blksize) {
|
---|
| 501 | #ifndef NO_IO_CACHE
|
---|
| 502 | if ((retval = flush_cached_blocks(channel, data, 0)))
|
---|
| 503 | return retval;
|
---|
| 504 | #endif
|
---|
| 505 |
|
---|
| 506 | channel->block_size = blksize;
|
---|
| 507 | free_cache(data);
|
---|
| 508 | if ((retval = alloc_cache(channel, data)))
|
---|
| 509 | return retval;
|
---|
| 510 | }
|
---|
| 511 | return 0;
|
---|
| 512 | }
|
---|
| 513 |
|
---|
| 514 |
|
---|
| 515 | static errcode_t unix_read_blk(io_channel channel, unsigned long block,
|
---|
| 516 | int count, void *buf)
|
---|
| 517 | {
|
---|
| 518 | struct unix_private_data *data;
|
---|
| 519 | struct unix_cache *cache, *reuse[READ_DIRECT_SIZE];
|
---|
| 520 | errcode_t retval;
|
---|
| 521 | char *cp;
|
---|
| 522 | int i, j;
|
---|
| 523 |
|
---|
| 524 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
| 525 | data = (struct unix_private_data *) channel->private_data;
|
---|
| 526 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
| 527 |
|
---|
| 528 | #ifdef NO_IO_CACHE
|
---|
| 529 | return raw_read_blk(channel, data, block, count, buf);
|
---|
| 530 | #else
|
---|
| 531 | /*
|
---|
| 532 | * If we're doing an odd-sized read or a very large read,
|
---|
| 533 | * flush out the cache and then do a direct read.
|
---|
| 534 | */
|
---|
| 535 | if (count < 0 || count > WRITE_DIRECT_SIZE) {
|
---|
| 536 | if ((retval = flush_cached_blocks(channel, data, 0)))
|
---|
| 537 | return retval;
|
---|
| 538 | return raw_read_blk(channel, data, block, count, buf);
|
---|
| 539 | }
|
---|
| 540 |
|
---|
| 541 | cp = buf;
|
---|
| 542 | while (count > 0) {
|
---|
| 543 | /* If it's in the cache, use it! */
|
---|
| 544 | if ((cache = find_cached_block(data, block, &reuse[0]))) {
|
---|
| 545 | #ifdef DEBUG
|
---|
| 546 | printf("Using cached block %d\n", block);
|
---|
| 547 | #endif
|
---|
| 548 | memcpy(cp, cache->buf, channel->block_size);
|
---|
| 549 | count--;
|
---|
| 550 | block++;
|
---|
| 551 | cp += channel->block_size;
|
---|
| 552 | continue;
|
---|
| 553 | }
|
---|
| 554 | /*
|
---|
| 555 | * Find the number of uncached blocks so we can do a
|
---|
| 556 | * single read request
|
---|
| 557 | */
|
---|
| 558 | for (i=1; i < count; i++)
|
---|
| 559 | if (find_cached_block(data, block+i, &reuse[i]))
|
---|
| 560 | break;
|
---|
| 561 | #ifdef DEBUG
|
---|
| 562 | printf("Reading %d blocks starting at %d\n", i, block);
|
---|
| 563 | #endif
|
---|
| 564 | if ((retval = raw_read_blk(channel, data, block, i, cp)))
|
---|
| 565 | return retval;
|
---|
| 566 |
|
---|
| 567 | /* Save the results in the cache */
|
---|
| 568 | for (j=0; j < i; j++) {
|
---|
| 569 | count--;
|
---|
| 570 | cache = reuse[j];
|
---|
| 571 | reuse_cache(channel, data, cache, block++);
|
---|
| 572 | memcpy(cache->buf, cp, channel->block_size);
|
---|
| 573 | cp += channel->block_size;
|
---|
| 574 | }
|
---|
| 575 | }
|
---|
| 576 | return 0;
|
---|
| 577 | #endif /* NO_IO_CACHE */
|
---|
| 578 | }
|
---|
| 579 |
|
---|
| 580 | static errcode_t unix_write_blk(io_channel channel, unsigned long block,
|
---|
| 581 | int count, const void *buf)
|
---|
| 582 | {
|
---|
| 583 | struct unix_private_data *data;
|
---|
| 584 | struct unix_cache *cache, *reuse;
|
---|
| 585 | errcode_t retval = 0;
|
---|
| 586 | const char *cp;
|
---|
| 587 | int writethrough;
|
---|
| 588 |
|
---|
| 589 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
| 590 | data = (struct unix_private_data *) channel->private_data;
|
---|
| 591 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
| 592 |
|
---|
| 593 | #ifdef NO_IO_CACHE
|
---|
| 594 | return raw_write_blk(channel, data, block, count, buf);
|
---|
| 595 | #else
|
---|
| 596 | /*
|
---|
| 597 | * If we're doing an odd-sized write or a very large write,
|
---|
| 598 | * flush out the cache completely and then do a direct write.
|
---|
| 599 | */
|
---|
| 600 | if (count < 0 || count > WRITE_DIRECT_SIZE) {
|
---|
| 601 | if ((retval = flush_cached_blocks(channel, data, 1)))
|
---|
| 602 | return retval;
|
---|
| 603 | return raw_write_blk(channel, data, block, count, buf);
|
---|
| 604 | }
|
---|
| 605 |
|
---|
| 606 | /*
|
---|
| 607 | * For a moderate-sized multi-block write, first force a write
|
---|
| 608 | * if we're in write-through cache mode, and then fill the
|
---|
| 609 | * cache with the blocks.
|
---|
| 610 | */
|
---|
| 611 | writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH;
|
---|
| 612 | if (writethrough)
|
---|
| 613 | retval = raw_write_blk(channel, data, block, count, buf);
|
---|
| 614 |
|
---|
| 615 | cp = buf;
|
---|
| 616 | while (count > 0) {
|
---|
| 617 | cache = find_cached_block(data, block, &reuse);
|
---|
| 618 | if (!cache) {
|
---|
| 619 | cache = reuse;
|
---|
| 620 | reuse_cache(channel, data, cache, block);
|
---|
| 621 | }
|
---|
| 622 | memcpy(cache->buf, cp, channel->block_size);
|
---|
| 623 | cache->dirty = !writethrough;
|
---|
| 624 | count--;
|
---|
| 625 | block++;
|
---|
| 626 | cp += channel->block_size;
|
---|
| 627 | }
|
---|
| 628 | return retval;
|
---|
| 629 | #endif /* NO_IO_CACHE */
|
---|
| 630 | }
|
---|
| 631 |
|
---|
| 632 | static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
|
---|
| 633 | int size, const void *buf)
|
---|
| 634 | {
|
---|
| 635 | struct unix_private_data *data;
|
---|
| 636 | errcode_t retval = 0;
|
---|
| 637 | ssize_t actual;
|
---|
| 638 |
|
---|
| 639 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
| 640 | data = (struct unix_private_data *) channel->private_data;
|
---|
| 641 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
| 642 |
|
---|
| 643 | #ifndef NO_IO_CACHE
|
---|
| 644 | /*
|
---|
| 645 | * Flush out the cache completely
|
---|
| 646 | */
|
---|
| 647 | if ((retval = flush_cached_blocks(channel, data, 1)))
|
---|
| 648 | return retval;
|
---|
| 649 | #endif
|
---|
| 650 |
|
---|
| 651 | if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0)
|
---|
| 652 | return errno;
|
---|
| 653 |
|
---|
| 654 | actual = write(data->dev, buf, size);
|
---|
| 655 | if (actual != size)
|
---|
| 656 | return EXT2_ET_SHORT_WRITE;
|
---|
| 657 |
|
---|
| 658 | return 0;
|
---|
| 659 | }
|
---|
| 660 |
|
---|
| 661 | /*
|
---|
| 662 | * Flush data buffers to disk.
|
---|
| 663 | */
|
---|
| 664 | static errcode_t unix_flush(io_channel channel)
|
---|
| 665 | {
|
---|
| 666 | struct unix_private_data *data;
|
---|
| 667 | errcode_t retval = 0;
|
---|
| 668 |
|
---|
| 669 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
| 670 | data = (struct unix_private_data *) channel->private_data;
|
---|
| 671 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
| 672 |
|
---|
| 673 | #ifndef NO_IO_CACHE
|
---|
| 674 | retval = flush_cached_blocks(channel, data, 0);
|
---|
| 675 | #endif
|
---|
| 676 | fsync(data->dev);
|
---|
| 677 | return retval;
|
---|
| 678 | }
|
---|
| 679 |
|
---|
| 680 | static errcode_t unix_set_option(io_channel channel, const char *option,
|
---|
| 681 | const char *arg)
|
---|
| 682 | {
|
---|
| 683 | struct unix_private_data *data;
|
---|
| 684 | unsigned long tmp;
|
---|
| 685 | char *end;
|
---|
| 686 |
|
---|
| 687 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
| 688 | data = (struct unix_private_data *) channel->private_data;
|
---|
| 689 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
| 690 |
|
---|
| 691 | if (!strcmp(option, "offset")) {
|
---|
| 692 | if (!arg)
|
---|
| 693 | return EXT2_ET_INVALID_ARGUMENT;
|
---|
| 694 |
|
---|
| 695 | tmp = strtoul(arg, &end, 0);
|
---|
| 696 | if (*end)
|
---|
| 697 | return EXT2_ET_INVALID_ARGUMENT;
|
---|
| 698 | data->offset = tmp;
|
---|
| 699 | return 0;
|
---|
| 700 | }
|
---|
| 701 | return EXT2_ET_INVALID_ARGUMENT;
|
---|
| 702 | }
|
---|