Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * JFFS2 -- Journalling Flash File System, Version 2. |
| 3 | * |
| 4 | * Copyright (C) 2001-2003 Red Hat, Inc. |
| 5 | * |
| 6 | * Created by David Woodhouse <dwmw2@infradead.org> |
| 7 | * |
| 8 | * For licensing information, see the file 'LICENCE' in this directory. |
| 9 | * |
Artem B. Bityutskiy | e0c8e42 | 2005-07-24 16:14:17 +0100 | [diff] [blame] | 10 | * $Id: read.c,v 1.41 2005/07/22 10:32:08 dedekind Exp $ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | * |
| 12 | */ |
| 13 | |
| 14 | #include <linux/kernel.h> |
| 15 | #include <linux/slab.h> |
| 16 | #include <linux/crc32.h> |
| 17 | #include <linux/pagemap.h> |
| 18 | #include <linux/mtd/mtd.h> |
| 19 | #include <linux/compiler.h> |
| 20 | #include "nodelist.h" |
| 21 | #include "compr.h" |
| 22 | |
| 23 | int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, |
| 24 | struct jffs2_full_dnode *fd, unsigned char *buf, |
| 25 | int ofs, int len) |
| 26 | { |
| 27 | struct jffs2_raw_inode *ri; |
| 28 | size_t readlen; |
| 29 | uint32_t crc; |
| 30 | unsigned char *decomprbuf = NULL; |
| 31 | unsigned char *readbuf = NULL; |
| 32 | int ret = 0; |
| 33 | |
| 34 | ri = jffs2_alloc_raw_inode(); |
| 35 | if (!ri) |
| 36 | return -ENOMEM; |
| 37 | |
| 38 | ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri); |
| 39 | if (ret) { |
| 40 | jffs2_free_raw_inode(ri); |
| 41 | printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret); |
| 42 | return ret; |
| 43 | } |
| 44 | if (readlen != sizeof(*ri)) { |
| 45 | jffs2_free_raw_inode(ri); |
| 46 | printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n", |
| 47 | ref_offset(fd->raw), sizeof(*ri), readlen); |
| 48 | return -EIO; |
| 49 | } |
| 50 | crc = crc32(0, ri, sizeof(*ri)-8); |
| 51 | |
| 52 | D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n", |
| 53 | ref_offset(fd->raw), je32_to_cpu(ri->node_crc), |
| 54 | crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize), |
| 55 | je32_to_cpu(ri->offset), buf)); |
| 56 | if (crc != je32_to_cpu(ri->node_crc)) { |
| 57 | printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n", |
| 58 | je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw)); |
| 59 | ret = -EIO; |
| 60 | goto out_ri; |
| 61 | } |
| 62 | /* There was a bug where we wrote hole nodes out with csize/dsize |
| 63 | swapped. Deal with it */ |
| 64 | if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) && |
| 65 | je32_to_cpu(ri->csize)) { |
| 66 | ri->dsize = ri->csize; |
| 67 | ri->csize = cpu_to_je32(0); |
| 68 | } |
| 69 | |
| 70 | D1(if(ofs + len > je32_to_cpu(ri->dsize)) { |
| 71 | printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n", |
| 72 | len, ofs, je32_to_cpu(ri->dsize)); |
| 73 | ret = -EINVAL; |
| 74 | goto out_ri; |
| 75 | }); |
| 76 | |
| 77 | |
| 78 | if (ri->compr == JFFS2_COMPR_ZERO) { |
| 79 | memset(buf, 0, len); |
| 80 | goto out_ri; |
| 81 | } |
| 82 | |
| 83 | /* Cases: |
| 84 | Reading whole node and it's uncompressed - read directly to buffer provided, check CRC. |
| 85 | Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided |
| 86 | Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy |
| 87 | Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy |
| 88 | */ |
| 89 | if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) { |
| 90 | readbuf = buf; |
| 91 | } else { |
| 92 | readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL); |
| 93 | if (!readbuf) { |
| 94 | ret = -ENOMEM; |
| 95 | goto out_ri; |
| 96 | } |
| 97 | } |
| 98 | if (ri->compr != JFFS2_COMPR_NONE) { |
| 99 | if (len < je32_to_cpu(ri->dsize)) { |
| 100 | decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL); |
| 101 | if (!decomprbuf) { |
| 102 | ret = -ENOMEM; |
| 103 | goto out_readbuf; |
| 104 | } |
| 105 | } else { |
| 106 | decomprbuf = buf; |
| 107 | } |
| 108 | } else { |
| 109 | decomprbuf = readbuf; |
| 110 | } |
| 111 | |
| 112 | D2(printk(KERN_DEBUG "Read %d bytes to %p\n", je32_to_cpu(ri->csize), |
| 113 | readbuf)); |
| 114 | ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri), |
| 115 | je32_to_cpu(ri->csize), &readlen, readbuf); |
| 116 | |
| 117 | if (!ret && readlen != je32_to_cpu(ri->csize)) |
| 118 | ret = -EIO; |
| 119 | if (ret) |
| 120 | goto out_decomprbuf; |
| 121 | |
| 122 | crc = crc32(0, readbuf, je32_to_cpu(ri->csize)); |
| 123 | if (crc != je32_to_cpu(ri->data_crc)) { |
| 124 | printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n", |
| 125 | je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw)); |
| 126 | ret = -EIO; |
| 127 | goto out_decomprbuf; |
| 128 | } |
| 129 | D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc)); |
| 130 | if (ri->compr != JFFS2_COMPR_NONE) { |
| 131 | D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n", |
| 132 | je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf)); |
| 133 | ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize)); |
| 134 | if (ret) { |
| 135 | printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret); |
| 136 | goto out_decomprbuf; |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | if (len < je32_to_cpu(ri->dsize)) { |
| 141 | memcpy(buf, decomprbuf+ofs, len); |
| 142 | } |
| 143 | out_decomprbuf: |
| 144 | if(decomprbuf != buf && decomprbuf != readbuf) |
| 145 | kfree(decomprbuf); |
| 146 | out_readbuf: |
| 147 | if(readbuf != buf) |
| 148 | kfree(readbuf); |
| 149 | out_ri: |
| 150 | jffs2_free_raw_inode(ri); |
| 151 | |
| 152 | return ret; |
| 153 | } |
| 154 | |
| 155 | int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f, |
| 156 | unsigned char *buf, uint32_t offset, uint32_t len) |
| 157 | { |
| 158 | uint32_t end = offset + len; |
| 159 | struct jffs2_node_frag *frag; |
| 160 | int ret; |
| 161 | |
| 162 | D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n", |
| 163 | f->inocache->ino, offset, offset+len)); |
| 164 | |
| 165 | frag = jffs2_lookup_node_frag(&f->fragtree, offset); |
| 166 | |
| 167 | /* XXX FIXME: Where a single physical node actually shows up in two |
| 168 | frags, we read it twice. Don't do that. */ |
| 169 | /* Now we're pointing at the first frag which overlaps our page */ |
| 170 | while(offset < end) { |
| 171 | D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end)); |
| 172 | if (unlikely(!frag || frag->ofs > offset)) { |
| 173 | uint32_t holesize = end - offset; |
| 174 | if (frag) { |
| 175 | D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset)); |
| 176 | holesize = min(holesize, frag->ofs - offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | } |
| 178 | D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize)); |
| 179 | memset(buf, 0, holesize); |
| 180 | buf += holesize; |
| 181 | offset += holesize; |
| 182 | continue; |
| 183 | } else if (unlikely(!frag->node)) { |
| 184 | uint32_t holeend = min(end, frag->ofs + frag->size); |
| 185 | D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size)); |
| 186 | memset(buf, 0, holeend - offset); |
| 187 | buf += holeend - offset; |
| 188 | offset = holeend; |
| 189 | frag = frag_next(frag); |
| 190 | continue; |
| 191 | } else { |
| 192 | uint32_t readlen; |
| 193 | uint32_t fragofs; /* offset within the frag to start reading */ |
| 194 | |
| 195 | fragofs = offset - frag->ofs; |
| 196 | readlen = min(frag->size - fragofs, end - offset); |
| 197 | D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n", |
| 198 | frag->ofs+fragofs, frag->ofs+fragofs+readlen, |
| 199 | ref_offset(frag->node->raw), ref_flags(frag->node->raw))); |
| 200 | ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen); |
| 201 | D2(printk(KERN_DEBUG "node read done\n")); |
| 202 | if (ret) { |
| 203 | D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret)); |
| 204 | memset(buf, 0, readlen); |
| 205 | return ret; |
| 206 | } |
| 207 | buf += readlen; |
| 208 | offset += readlen; |
| 209 | frag = frag_next(frag); |
| 210 | D2(printk(KERN_DEBUG "node read was OK. Looping\n")); |
| 211 | } |
| 212 | } |
| 213 | return 0; |
| 214 | } |
| 215 | |