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         int i;
  64         int blockcnt;
  65         int log2blocksize = LOG2_EXT2_BLOCK_SIZE(node->data);
  66         int blocksize = 1 << (log2blocksize + DISK_SECTOR_BITS);
  67         unsigned int filesize = __le32_to_cpu(node->inode.size);
  68         int previous_block_number = -1;
  69         int delayed_start = 0;
  70         int delayed_extent = 0;
  71         int delayed_skipfirst = 0;
  72         int delayed_next = 0;
  73         char *delayed_buf = NULL;
  74         short status;
  75
  76         /* Adjust len so it we can't read past the end of the file. */
  77         if (len > filesize)
  78                 len = filesize;
  79
  80         blockcnt = ((len + pos) + blocksize - 1) / blocksize;
  81
  82         for (i = pos / blocksize; i < blockcnt; i++) {
  83                 int blknr;
  84                 int blockoff = pos % blocksize;
  85                 int blockend = blocksize;
  86                 int skipfirst = 0;
  87                 blknr = read_allocated_block(&(node->inode), i);
  88                 if (blknr < 0)
  89                         return -1;
  90
  91                 blknr = blknr << log2blocksize;
  92
  93                 /* Last block.  */
  94                 if (i == blockcnt - 1) {
  95                         blockend = (len + pos) % blocksize;
  96
  97                         /* The last portion is exactly blocksize. */
  98                         if (!blockend)
  99                                 blockend = blocksize;
 100                 }
 101
 102                 /* First block. */
 103                 if (i == pos / blocksize) {
 104                         skipfirst = blockoff;
 105                         blockend -= skipfirst;
 106                 }
 107                 if (blknr) {
 108                         int status;
 109
 110                         if (previous_block_number != -1) {
 111                                 if (delayed_next == blknr) {
 112                                         delayed_extent += blockend;
 113                                         delayed_next += blockend >> SECTOR_BITS;
 114                                 } else {        /* spill */
 115                                         status = ext4fs_devread(delayed_start,
 116                                                         delayed_skipfirst,
 117                                                         delayed_extent,
 118                                                         delayed_buf);
 119                                         if (status == 0)
 120                                                 return -1;
 121                                         previous_block_number = blknr;
 122                                         delayed_start = blknr;
 123                                         delayed_extent = blockend;
 124                                         delayed_skipfirst = skipfirst;
 125                                         delayed_buf = buf;
 126                                         delayed_next = blknr +
 127                                                 (blockend >> SECTOR_BITS);
 128                                 }
 129                         } else {
 130                                 previous_block_number = blknr;
 131                                 delayed_start = blknr;
 132                                 delayed_extent = blockend;
 133                                 delayed_skipfirst = skipfirst;
 134                                 delayed_buf = buf;
 135                                 delayed_next = blknr +
 136                                         (blockend >> SECTOR_BITS);
 137                         }
 138                 } else {
 139                         if (previous_block_number != -1) {
 140                                 /* spill */
 141                                 status = ext4fs_devread(delayed_start,
 142                                                         delayed_skipfirst,
 143                                                         delayed_extent,
 144                                                         delayed_buf);
 145                                 if (status == 0)
 146                                         return -1;
 147                                 previous_block_number = -1;
 148                         }
 149                         memset(buf, 0, blocksize - skipfirst);
 150                 }
 151                 buf += blocksize - skipfirst;
 152         }
 153         if (previous_block_number != -1) {
 154                 /* spill */
 155                 status = ext4fs_devread(delayed_start,
 156                                         delayed_skipfirst, delayed_extent,
 157                                         delayed_buf);
 158                 if (status == 0)
 159                         return -1;
 160                 previous_block_number = -1;
 161         }
 162
 163         return len;
 164 }
 165
 166 int ext4fs_ls(const char *dirname)
 167 {
 168         struct ext2fs_node *dirnode;
 169         int status;
 170
 171         if (dirname == NULL)
 172                 return 0;
 173
 174         status = ext4fs_find_file(dirname, &ext4fs_root->diropen, &dirnode,
 175                                   FILETYPE_DIRECTORY);
 176         if (status != 1) {
 177                 printf("** Can not find directory. **\n");
 178                 return 1;
 179         }
 180
 181         ext4fs_iterate_dir(dirnode, NULL, NULL, NULL);
 182         ext4fs_free_node(dirnode, &ext4fs_root->diropen);
 183
 184         return 0;
 185 }
 186
 187 int ext4fs_read(char *buf, unsigned len)
 188 {
 189         if (ext4fs_root == NULL || ext4fs_file == NULL)
 190                 return 0;
 191
 192         return ext4fs_read_file(ext4fs_file, 0, len, buf);
 193 }