217 строки
6.8 KiB
C
217 строки
6.8 KiB
C
/*
|
|
* JFFS2 -- Journalling Flash File System, Version 2.
|
|
*
|
|
* Copyright (C) 2001-2003 Red Hat, Inc.
|
|
*
|
|
* Created by David Woodhouse <dwmw2@infradead.org>
|
|
*
|
|
* For licensing information, see the file 'LICENCE' in this directory.
|
|
*
|
|
* $Id: read.c,v 1.39 2005/03/01 10:34:03 dedekind Exp $
|
|
*
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/crc32.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/mtd/mtd.h>
|
|
#include <linux/compiler.h>
|
|
#include "nodelist.h"
|
|
#include "compr.h"
|
|
|
|
int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
|
|
struct jffs2_full_dnode *fd, unsigned char *buf,
|
|
int ofs, int len)
|
|
{
|
|
struct jffs2_raw_inode *ri;
|
|
size_t readlen;
|
|
uint32_t crc;
|
|
unsigned char *decomprbuf = NULL;
|
|
unsigned char *readbuf = NULL;
|
|
int ret = 0;
|
|
|
|
ri = jffs2_alloc_raw_inode();
|
|
if (!ri)
|
|
return -ENOMEM;
|
|
|
|
ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri);
|
|
if (ret) {
|
|
jffs2_free_raw_inode(ri);
|
|
printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret);
|
|
return ret;
|
|
}
|
|
if (readlen != sizeof(*ri)) {
|
|
jffs2_free_raw_inode(ri);
|
|
printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
|
|
ref_offset(fd->raw), sizeof(*ri), readlen);
|
|
return -EIO;
|
|
}
|
|
crc = crc32(0, ri, sizeof(*ri)-8);
|
|
|
|
D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
|
|
ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
|
|
crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
|
|
je32_to_cpu(ri->offset), buf));
|
|
if (crc != je32_to_cpu(ri->node_crc)) {
|
|
printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n",
|
|
je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
|
|
ret = -EIO;
|
|
goto out_ri;
|
|
}
|
|
/* There was a bug where we wrote hole nodes out with csize/dsize
|
|
swapped. Deal with it */
|
|
if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
|
|
je32_to_cpu(ri->csize)) {
|
|
ri->dsize = ri->csize;
|
|
ri->csize = cpu_to_je32(0);
|
|
}
|
|
|
|
D1(if(ofs + len > je32_to_cpu(ri->dsize)) {
|
|
printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
|
|
len, ofs, je32_to_cpu(ri->dsize));
|
|
ret = -EINVAL;
|
|
goto out_ri;
|
|
});
|
|
|
|
|
|
if (ri->compr == JFFS2_COMPR_ZERO) {
|
|
memset(buf, 0, len);
|
|
goto out_ri;
|
|
}
|
|
|
|
/* Cases:
|
|
Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
|
|
Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
|
|
Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
|
|
Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
|
|
*/
|
|
if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) {
|
|
readbuf = buf;
|
|
} else {
|
|
readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
|
|
if (!readbuf) {
|
|
ret = -ENOMEM;
|
|
goto out_ri;
|
|
}
|
|
}
|
|
if (ri->compr != JFFS2_COMPR_NONE) {
|
|
if (len < je32_to_cpu(ri->dsize)) {
|
|
decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
|
|
if (!decomprbuf) {
|
|
ret = -ENOMEM;
|
|
goto out_readbuf;
|
|
}
|
|
} else {
|
|
decomprbuf = buf;
|
|
}
|
|
} else {
|
|
decomprbuf = readbuf;
|
|
}
|
|
|
|
D2(printk(KERN_DEBUG "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
|
|
readbuf));
|
|
ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri),
|
|
je32_to_cpu(ri->csize), &readlen, readbuf);
|
|
|
|
if (!ret && readlen != je32_to_cpu(ri->csize))
|
|
ret = -EIO;
|
|
if (ret)
|
|
goto out_decomprbuf;
|
|
|
|
crc = crc32(0, readbuf, je32_to_cpu(ri->csize));
|
|
if (crc != je32_to_cpu(ri->data_crc)) {
|
|
printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n",
|
|
je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
|
|
ret = -EIO;
|
|
goto out_decomprbuf;
|
|
}
|
|
D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc));
|
|
if (ri->compr != JFFS2_COMPR_NONE) {
|
|
D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n",
|
|
je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf));
|
|
ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
|
|
if (ret) {
|
|
printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret);
|
|
goto out_decomprbuf;
|
|
}
|
|
}
|
|
|
|
if (len < je32_to_cpu(ri->dsize)) {
|
|
memcpy(buf, decomprbuf+ofs, len);
|
|
}
|
|
out_decomprbuf:
|
|
if(decomprbuf != buf && decomprbuf != readbuf)
|
|
kfree(decomprbuf);
|
|
out_readbuf:
|
|
if(readbuf != buf)
|
|
kfree(readbuf);
|
|
out_ri:
|
|
jffs2_free_raw_inode(ri);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
|
|
unsigned char *buf, uint32_t offset, uint32_t len)
|
|
{
|
|
uint32_t end = offset + len;
|
|
struct jffs2_node_frag *frag;
|
|
int ret;
|
|
|
|
D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n",
|
|
f->inocache->ino, offset, offset+len));
|
|
|
|
frag = jffs2_lookup_node_frag(&f->fragtree, offset);
|
|
|
|
/* XXX FIXME: Where a single physical node actually shows up in two
|
|
frags, we read it twice. Don't do that. */
|
|
/* Now we're pointing at the first frag which overlaps our page */
|
|
while(offset < end) {
|
|
D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end));
|
|
if (unlikely(!frag || frag->ofs > offset)) {
|
|
uint32_t holesize = end - offset;
|
|
if (frag) {
|
|
D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset));
|
|
holesize = min(holesize, frag->ofs - offset);
|
|
D2(jffs2_print_frag_list(f));
|
|
}
|
|
D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize));
|
|
memset(buf, 0, holesize);
|
|
buf += holesize;
|
|
offset += holesize;
|
|
continue;
|
|
} else if (unlikely(!frag->node)) {
|
|
uint32_t holeend = min(end, frag->ofs + frag->size);
|
|
D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size));
|
|
memset(buf, 0, holeend - offset);
|
|
buf += holeend - offset;
|
|
offset = holeend;
|
|
frag = frag_next(frag);
|
|
continue;
|
|
} else {
|
|
uint32_t readlen;
|
|
uint32_t fragofs; /* offset within the frag to start reading */
|
|
|
|
fragofs = offset - frag->ofs;
|
|
readlen = min(frag->size - fragofs, end - offset);
|
|
D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n",
|
|
frag->ofs+fragofs, frag->ofs+fragofs+readlen,
|
|
ref_offset(frag->node->raw), ref_flags(frag->node->raw)));
|
|
ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
|
|
D2(printk(KERN_DEBUG "node read done\n"));
|
|
if (ret) {
|
|
D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret));
|
|
memset(buf, 0, readlen);
|
|
return ret;
|
|
}
|
|
buf += readlen;
|
|
offset += readlen;
|
|
frag = frag_next(frag);
|
|
D2(printk(KERN_DEBUG "node read was OK. Looping\n"));
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|