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[/] [or1k/] [trunk/] [ecos-2.0/] [packages/] [fs/] [jffs2/] [v2_0/] [src/] [read.c] - Rev 1254
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/* * JFFS2 -- Journalling Flash File System, Version 2. * * Copyright (C) 2001, 2002 Red Hat, Inc. * * Created by David Woodhouse <dwmw2@cambridge.redhat.com> * * For licensing information, see the file 'LICENCE' in this directory. * * $Id: read.c,v 1.1.1.1 2004-02-14 13:29:20 phoenix Exp $ * */ #include <linux/kernel.h> #include <linux/slab.h> #include <linux/crc32.h> #include <linux/pagemap.h> #include <linux/mtd/mtd.h> #include "nodelist.h" int jffs2_read_dnode(struct jffs2_sb_info *c, 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(ri->compr, 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 (!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); D1(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 (frag->ofs < offset && (offset & (PAGE_CACHE_SIZE-1)) != 0) { D1(printk(KERN_NOTICE "Eep. Overlap in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset)); D1(jffs2_print_frag_list(f)); memset(buf, 0, end - offset); return -EIO; } else if (!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, 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; } /* Core function to read symlink target. */ char *jffs2_getlink(struct jffs2_sb_info *c, struct jffs2_inode_info *f) { char *buf; int ret; down(&f->sem); if (!f->metadata) { printk(KERN_NOTICE "No metadata for symlink inode #%u\n", f->inocache->ino); up(&f->sem); return ERR_PTR(-EINVAL); } buf = kmalloc(f->metadata->size+1, GFP_USER); if (!buf) { up(&f->sem); return ERR_PTR(-ENOMEM); } buf[f->metadata->size]=0; ret = jffs2_read_dnode(c, f->metadata, buf, 0, f->metadata->size); up(&f->sem); if (ret) { kfree(buf); return ERR_PTR(ret); } return buf; }
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