fs/ext4/ext4fs.c

   1 /*
   2  * (C) Copyright 2011 - 2012 Samsung Electronics
   3  * EXT4 filesystem implementation in Uboot by
   4  * Uma Shankar <uma.shankar@samsung.com>
   5  * Manjunatha C Achar <a.manjunatha@samsung.com>
   6  *
   7  * ext4ls and ext4load : Based on ext2 ls and load support in Uboot.
   8  *                     Ext4 read optimization taken from Open-Moko
   9  *                     Qi bootloader
  10  *
  11  * (C) Copyright 2004
  12  * esd gmbh <www.esd-electronics.com>
  13  * Reinhard Arlt <reinhard.arlt@esd-electronics.com>
  14  *
  15  * based on code from grub2 fs/ext2.c and fs/fshelp.c by
  16  * GRUB  --  GRand Unified Bootloader
  17  * Copyright (C) 2003, 2004  Free Software Foundation, Inc.
  18  *
  19  * ext4write : Based on generic ext4 protocol.
  20  *
  21  * This program is free software; you can redistribute it and/or modify
  22  * it under the terms of the GNU General Public License as published by
  23  * the Free Software Foundation; either version 2 of the License, or
  24  * (at your option) any later version.
  25  *
  26  * This program is distributed in the hope that it will be useful,
  27  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  * GNU General Public License for more details.
  30  *
  31  * You should have received a copy of the GNU General Public License
  32  * along with this program; if not, write to the Free Software
  33  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  34  */
  35
  36 #include <common.h>
  37 #include <ext_common.h>
  38 #include <ext4fs.h>
  39 #include "ext4_common.h"
  40
  41 int ext4fs_symlinknest;
  42 struct ext_filesystem ext_fs;
  43
  44 struct ext_filesystem *get_fs(void)
  45 {
  46         return &ext_fs;
  47 }
  48
  49 void ext4fs_free_node(struct ext2fs_node *node, struct ext2fs_node *currroot)
  50 {
  51         if ((node != &ext4fs_root->diropen) && (node != currroot))
  52                 free(node);
  53 }
  54
  55 /*
  56  * Taken from openmoko-kernel mailing list: By Andy green
  57  * Optimized read file API : collects and defers contiguous sector
  58  * reads into one potentially more efficient larger sequential read action
  59  */
  60 int ext4fs_read_file(struct ext2fs_node *node, int pos,
  61                 unsigned int len, char *buf)
  62 {
  63         struct ext_filesystem *fs = get_fs();
  64         int i;
  65         int blockcnt;
  66         int log2blksz = fs->dev_desc->log2blksz;
  67         int log2_fs_blocksize = LOG2_BLOCK_SIZE(node->data) - log2blksz;
  68         int blocksize = (1 << (log2_fs_blocksize + log2blksz));
  69         unsigned int filesize = __le32_to_cpu(node->inode.size);
  70         int previous_block_number = -1;
  71         int delayed_start = 0;
  72         int delayed_extent = 0;
  73         int delayed_skipfirst = 0;
  74         int delayed_next = 0;
  75         char *delayed_buf = NULL;
  76         short status;
  77
  78         /* Adjust len so it we can't read past the end of the file. */
  79         if (len > filesize)
  80                 len = filesize;
  81
  82         blockcnt = ((len + pos) + blocksize - 1) / blocksize;
  83
  84         for (i = pos / blocksize; i < blockcnt; i++) {
  85                 int blknr;
  86                 int blockoff = pos % blocksize;
  87                 int blockend = blocksize;
  88                 int skipfirst = 0;
  89                 blknr = read_allocated_block(&(node->inode), i);
  90                 if (blknr < 0)
  91                         return -1;
  92
  93                 blknr = blknr << log2_fs_blocksize;
  94
  95                 /* Last block.  */
  96                 if (i == blockcnt - 1) {
  97                         blockend = (len + pos) % blocksize;
  98
  99                         /* The last portion is exactly blocksize. */
 100                         if (!blockend)
 101                                 blockend = blocksize;
 102                 }
 103
 104                 /* First block. */
 105                 if (i == pos / blocksize) {
 106                         skipfirst = blockoff;
 107                         blockend -= skipfirst;
 108                 }
 109                 if (blknr) {
 110                         int status;
 111
 112                         if (previous_block_number != -1) {
 113                                 if (delayed_next == blknr) {
 114                                         delayed_extent += blockend;
 115                                         delayed_next += blockend >> log2blksz;
 116                                 } else {        /* spill */
 117                                         status = ext4fs_devread(delayed_start,
 118                                                         delayed_skipfirst,
 119                                                         delayed_extent,
 120                                                         delayed_buf);
 121                                         if (status == 0)
 122                                                 return -1;
 123                                         previous_block_number = blknr;
 124                                         delayed_start = blknr;
 125                                         delayed_extent = blockend;
 126                                         delayed_skipfirst = skipfirst;
 127                                         delayed_buf = buf;
 128                                         delayed_next = blknr +
 129                                                 (blockend >> log2blksz);
 130                                 }
 131                         } else {
 132                                 previous_block_number = blknr;
 133                                 delayed_start = blknr;
 134                                 delayed_extent = blockend;
 135                                 delayed_skipfirst = skipfirst;
 136                                 delayed_buf = buf;
 137                                 delayed_next = blknr +
 138                                         (blockend >> log2blksz);
 139                         }
 140                 } else {
 141                         if (previous_block_number != -1) {
 142                                 /* spill */
 143                                 status = ext4fs_devread(delayed_start,
 144                                                         delayed_skipfirst,
 145                                                         delayed_extent,
 146                                                         delayed_buf);
 147                                 if (status == 0)
 148                                         return -1;
 149                                 previous_block_number = -1;
 150                         }
 151                         memset(buf, 0, blocksize - skipfirst);
 152                 }
 153                 buf += blocksize - skipfirst;
 154         }
 155         if (previous_block_number != -1) {
 156                 /* spill */
 157                 status = ext4fs_devread(delayed_start,
 158                                         delayed_skipfirst, delayed_extent,
 159                                         delayed_buf);
 160                 if (status == 0)
 161                         return -1;
 162                 previous_block_number = -1;
 163         }
 164
 165         return len;
 166 }
 167
 168 int ext4fs_ls(const char *dirname)
 169 {
 170         struct ext2fs_node *dirnode;
 171         int status;
 172
 173         if (dirname == NULL)
 174                 return 0;
 175
 176         status = ext4fs_find_file(dirname, &ext4fs_root->diropen, &dirnode,
 177                                   FILETYPE_DIRECTORY);
 178         if (status != 1) {
 179                 printf("** Can not find directory. **\n");
 180                 return 1;
 181         }
 182
 183         ext4fs_iterate_dir(dirnode, NULL, NULL, NULL);
 184         ext4fs_free_node(dirnode, &ext4fs_root->diropen);
 185
 186         return 0;
 187 }
 188
 189 int ext4fs_read(char *buf, unsigned len)
 190 {
 191         if (ext4fs_root == NULL || ext4fs_file == NULL)
 192                 return 0;
 193
 194         return ext4fs_read_file(ext4fs_file, 0, len, buf);
 195 }
 196
 197 int ext4fs_probe(block_dev_desc_t *fs_dev_desc,
 198                  disk_partition_t *fs_partition)
 199 {
 200         ext4fs_set_blk_dev(fs_dev_desc, fs_partition);
 201
 202         if (!ext4fs_mount(fs_partition->size)) {
 203                 ext4fs_close();
 204                 return -1;
 205         }
 206
 207         return 0;
 208 }
 209
 210 int ext4_read_file(const char *filename, void *buf, int offset, int len)
 211 {
 212         int file_len;
 213         int len_read;
 214
 215         if (offset != 0) {
 216                 printf("** Cannot support non-zero offset **\n");
 217                 return -1;
 218         }
 219
 220         file_len = ext4fs_open(filename);
 221         if (file_len < 0) {
 222                 printf("** File not found %s **\n", filename);
 223                 return -1;
 224         }
 225
 226         if (len == 0)
 227                 len = file_len;
 228
 229         len_read = ext4fs_read(buf, len);
 230
 231         return len_read;
 232 }