229 lines
6.7 KiB
C
229 lines
6.7 KiB
C
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/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright © 2001-2007 Red Hat, Inc.
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*
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* Created by David Woodhouse <dwmw2@infradead.org>
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*
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* For licensing information, see the file 'LICENCE' in this directory.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/crc32.h>
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#include <linux/pagemap.h>
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#include <linux/mtd/mtd.h>
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#include <linux/compiler.h>
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#include "nodelist.h"
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#include "compr.h"
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int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
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struct jffs2_full_dnode *fd, unsigned char *buf,
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int ofs, int len)
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{
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struct jffs2_raw_inode *ri;
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size_t readlen;
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uint32_t crc;
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unsigned char *decomprbuf = NULL;
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unsigned char *readbuf = NULL;
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int ret = 0;
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ri = jffs2_alloc_raw_inode();
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if (!ri)
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return -ENOMEM;
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ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri);
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if (ret) {
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jffs2_free_raw_inode(ri);
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pr_warn("Error reading node from 0x%08x: %d\n",
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ref_offset(fd->raw), ret);
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return ret;
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}
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if (readlen != sizeof(*ri)) {
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jffs2_free_raw_inode(ri);
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pr_warn("Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
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ref_offset(fd->raw), sizeof(*ri), readlen);
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return -EIO;
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}
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crc = crc32(0, ri, sizeof(*ri)-8);
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jffs2_dbg(1, "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
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ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
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crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
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je32_to_cpu(ri->offset), buf);
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if (crc != je32_to_cpu(ri->node_crc)) {
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pr_warn("Node CRC %08x != calculated CRC %08x for node at %08x\n",
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je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
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ret = -EIO;
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goto out_ri;
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}
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/* There was a bug where we wrote hole nodes out with csize/dsize
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swapped. Deal with it */
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if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
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je32_to_cpu(ri->csize)) {
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ri->dsize = ri->csize;
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ri->csize = cpu_to_je32(0);
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}
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D1(if(ofs + len > je32_to_cpu(ri->dsize)) {
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pr_warn("jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
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len, ofs, je32_to_cpu(ri->dsize));
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ret = -EINVAL;
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goto out_ri;
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});
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if (ri->compr == JFFS2_COMPR_ZERO) {
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memset(buf, 0, len);
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goto out_ri;
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}
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/* Cases:
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Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
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Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
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Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
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Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
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*/
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if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) {
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readbuf = buf;
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} else {
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readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
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if (!readbuf) {
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ret = -ENOMEM;
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goto out_ri;
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}
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}
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if (ri->compr != JFFS2_COMPR_NONE) {
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if (len < je32_to_cpu(ri->dsize)) {
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decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
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if (!decomprbuf) {
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ret = -ENOMEM;
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goto out_readbuf;
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}
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} else {
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decomprbuf = buf;
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}
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} else {
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decomprbuf = readbuf;
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}
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jffs2_dbg(2, "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
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readbuf);
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ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri),
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je32_to_cpu(ri->csize), &readlen, readbuf);
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if (!ret && readlen != je32_to_cpu(ri->csize))
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ret = -EIO;
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if (ret)
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goto out_decomprbuf;
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crc = crc32(0, readbuf, je32_to_cpu(ri->csize));
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if (crc != je32_to_cpu(ri->data_crc)) {
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pr_warn("Data CRC %08x != calculated CRC %08x for node at %08x\n",
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je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
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ret = -EIO;
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goto out_decomprbuf;
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}
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jffs2_dbg(2, "Data CRC matches calculated CRC %08x\n", crc);
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if (ri->compr != JFFS2_COMPR_NONE) {
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jffs2_dbg(2, "Decompress %d bytes from %p to %d bytes at %p\n",
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je32_to_cpu(ri->csize), readbuf,
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je32_to_cpu(ri->dsize), decomprbuf);
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ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
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if (ret) {
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pr_warn("Error: jffs2_decompress returned %d\n", ret);
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goto out_decomprbuf;
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}
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}
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if (len < je32_to_cpu(ri->dsize)) {
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memcpy(buf, decomprbuf+ofs, len);
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}
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out_decomprbuf:
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if(decomprbuf != buf && decomprbuf != readbuf)
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kfree(decomprbuf);
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out_readbuf:
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if(readbuf != buf)
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kfree(readbuf);
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out_ri:
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jffs2_free_raw_inode(ri);
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return ret;
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}
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int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
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unsigned char *buf, uint32_t offset, uint32_t len)
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{
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uint32_t end = offset + len;
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struct jffs2_node_frag *frag;
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int ret;
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jffs2_dbg(1, "%s(): ino #%u, range 0x%08x-0x%08x\n",
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__func__, f->inocache->ino, offset, offset + len);
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frag = jffs2_lookup_node_frag(&f->fragtree, offset);
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/* XXX FIXME: Where a single physical node actually shows up in two
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frags, we read it twice. Don't do that. */
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/* Now we're pointing at the first frag which overlaps our page
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* (or perhaps is before it, if we've been asked to read off the
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* end of the file). */
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while(offset < end) {
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jffs2_dbg(2, "%s(): offset %d, end %d\n",
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__func__, offset, end);
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if (unlikely(!frag || frag->ofs > offset ||
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frag->ofs + frag->size <= offset)) {
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uint32_t holesize = end - offset;
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if (frag && frag->ofs > offset) {
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jffs2_dbg(1, "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n",
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f->inocache->ino, frag->ofs, offset);
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holesize = min(holesize, frag->ofs - offset);
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}
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jffs2_dbg(1, "Filling non-frag hole from %d-%d\n",
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offset, offset + holesize);
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memset(buf, 0, holesize);
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buf += holesize;
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offset += holesize;
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continue;
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} else if (unlikely(!frag->node)) {
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uint32_t holeend = min(end, frag->ofs + frag->size);
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jffs2_dbg(1, "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n",
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offset, holeend, frag->ofs,
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frag->ofs + frag->size);
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memset(buf, 0, holeend - offset);
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buf += holeend - offset;
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offset = holeend;
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frag = frag_next(frag);
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continue;
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} else {
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uint32_t readlen;
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uint32_t fragofs; /* offset within the frag to start reading */
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fragofs = offset - frag->ofs;
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readlen = min(frag->size - fragofs, end - offset);
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jffs2_dbg(1, "Reading %d-%d from node at 0x%08x (%d)\n",
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frag->ofs+fragofs,
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frag->ofs + fragofs+readlen,
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ref_offset(frag->node->raw),
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ref_flags(frag->node->raw));
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ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
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jffs2_dbg(2, "node read done\n");
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if (ret) {
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jffs2_dbg(1, "%s(): error %d\n",
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__func__, ret);
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memset(buf, 0, readlen);
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return ret;
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}
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buf += readlen;
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offset += readlen;
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frag = frag_next(frag);
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jffs2_dbg(2, "node read was OK. Looping\n");
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}
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}
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return 0;
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}
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