예제 #1
0
파일: readinode.c 프로젝트: me-oss/me-linux
/*
 * Helper function for jffs2_get_inode_nodes().
 * It is called every time an inode node is found.
 *
 * Returns: 0 on succes;
 * 	    1 if the node should be marked obsolete;
 * 	    negative error code on failure.
 */
static inline int read_dnode(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
			     struct jffs2_raw_inode *rd, struct rb_root *tnp, int rdlen,
			     uint32_t *latest_mctime, uint32_t *mctime_ver)
{
	struct jffs2_tmp_dnode_info *tn;
	uint32_t len, csize;
	int ret = 1;

	/* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
	BUG_ON(ref_obsolete(ref));

	tn = jffs2_alloc_tmp_dnode_info();
	if (!tn) {
		JFFS2_ERROR("failed to allocate tn (%d bytes).\n", sizeof(*tn));
		return -ENOMEM;
	}

	tn->partial_crc = 0;
	csize = je32_to_cpu(rd->csize);

	/* If we've never checked the CRCs on this node, check them now */
	if (ref_flags(ref) == REF_UNCHECKED) {
		uint32_t crc;

		crc = crc32(0, rd, sizeof(*rd) - 8);
		if (unlikely(crc != je32_to_cpu(rd->node_crc))) {
			JFFS2_NOTICE("header CRC failed on node at %#08x: read %#08x, calculated %#08x\n",
					ref_offset(ref), je32_to_cpu(rd->node_crc), crc);
			goto free_out;
		}

		/* Sanity checks */
		if (unlikely(je32_to_cpu(rd->offset) > je32_to_cpu(rd->isize)) ||
		    unlikely(PAD(je32_to_cpu(rd->csize) + sizeof(*rd)) != PAD(je32_to_cpu(rd->totlen)))) {
				JFFS2_WARNING("inode node header CRC is corrupted at %#08x\n", ref_offset(ref));
				jffs2_dbg_dump_node(c, ref_offset(ref));
			goto free_out;
		}

		if (jffs2_is_writebuffered(c) && csize != 0) {
			/* At this point we are supposed to check the data CRC
			 * of our unchecked node. But thus far, we do not
			 * know whether the node is valid or obsolete. To
			 * figure this out, we need to walk all the nodes of
			 * the inode and build the inode fragtree. We don't
			 * want to spend time checking data of nodes which may
			 * later be found to be obsolete. So we put off the full
			 * data CRC checking until we have read all the inode
			 * nodes and have started building the fragtree.
			 *
			 * The fragtree is being built starting with nodes
			 * having the highest version number, so we'll be able
			 * to detect whether a node is valid (i.e., it is not
			 * overlapped by a node with higher version) or not.
			 * And we'll be able to check only those nodes, which
			 * are not obsolete.
			 *
			 * Of course, this optimization only makes sense in case
			 * of NAND flashes (or other flashes whith
			 * !jffs2_can_mark_obsolete()), since on NOR flashes
			 * nodes are marked obsolete physically.
			 *
			 * Since NAND flashes (or other flashes with
			 * jffs2_is_writebuffered(c)) are anyway read by
			 * fractions of c->wbuf_pagesize, and we have just read
			 * the node header, it is likely that the starting part
			 * of the node data is also read when we read the
			 * header. So we don't mind to check the CRC of the
			 * starting part of the data of the node now, and check
			 * the second part later (in jffs2_check_node_data()).
			 * Of course, we will not need to re-read and re-check
			 * the NAND page which we have just read. This is why we
			 * read the whole NAND page at jffs2_get_inode_nodes(),
			 * while we needed only the node header.
			 */
			unsigned char *buf;

			/* 'buf' will point to the start of data */
			buf = (unsigned char *)rd + sizeof(*rd);
			/* len will be the read data length */
			len = min_t(uint32_t, rdlen - sizeof(*rd), csize);
			tn->partial_crc = crc32(0, buf, len);

			dbg_readinode("Calculates CRC (%#08x) for %d bytes, csize %d\n", tn->partial_crc, len, csize);

			/* If we actually calculated the whole data CRC
			 * and it is wrong, drop the node. */
			if (len >= csize && unlikely(tn->partial_crc != je32_to_cpu(rd->data_crc))) {
				JFFS2_NOTICE("wrong data CRC in data node at 0x%08x: read %#08x, calculated %#08x.\n",
					ref_offset(ref), tn->partial_crc, je32_to_cpu(rd->data_crc));
				goto free_out;
			}

		} else if (csize == 0) {
			/*
			 * We checked the header CRC. If the node has no data, adjust
			 * the space accounting now. For other nodes this will be done
			 * later either when the node is marked obsolete or when its
			 * data is checked.
			 */
			struct jffs2_eraseblock *jeb;

			dbg_readinode("the node has no data.\n");
			jeb = &c->blocks[ref->flash_offset / c->sector_size];
			len = ref_totlen(c, jeb, ref);

			spin_lock(&c->erase_completion_lock);
			jeb->used_size += len;
			jeb->unchecked_size -= len;
			c->used_size += len;
			c->unchecked_size -= len;
			ref->flash_offset = ref_offset(ref) | REF_NORMAL;
			spin_unlock(&c->erase_completion_lock);
		}
	}

	tn->fn = jffs2_alloc_full_dnode();
	if (!tn->fn) {
		JFFS2_ERROR("alloc fn failed\n");
		ret = -ENOMEM;
		goto free_out;
	}

	tn->version = je32_to_cpu(rd->version);
	tn->fn->ofs = je32_to_cpu(rd->offset);
	tn->data_crc = je32_to_cpu(rd->data_crc);
	tn->csize = csize;
	tn->fn->raw = ref;

	/* There was a bug where we wrote hole nodes out with
	   csize/dsize swapped. Deal with it */
	if (rd->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(rd->dsize) && csize)
		tn->fn->size = csize;
	else // normal case...
		tn->fn->size = je32_to_cpu(rd->dsize);

	dbg_readinode("dnode @%08x: ver %u, offset %#04x, dsize %#04x, csize %#04x\n",
		  ref_offset(ref), je32_to_cpu(rd->version), je32_to_cpu(rd->offset), je32_to_cpu(rd->dsize), csize);

	jffs2_add_tn_to_tree(tn, tnp);

	return 0;

free_out:
	jffs2_free_tmp_dnode_info(tn);
	return ret;
}
예제 #2
0
/*
 * Helper function for jffs2_get_inode_nodes().
 * It is called every time an inode node is found.
 *
 * Returns: 0 on succes;
 * 	    1 if the node should be marked obsolete;
 * 	    negative error code on failure.
 */
static inline int
read_dnode(struct jffs2_sb_info *c,
	   struct jffs2_raw_node_ref *ref,
	   struct jffs2_raw_inode *rd,
	   uint32_t read,
	   struct rb_root *tnp,
	   int32_t *latest_mctime,
	   uint32_t *mctime_ver)
{
	struct jffs2_eraseblock *jeb;
	struct jffs2_tmp_dnode_info *tn;
	
	/* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
	BUG_ON(ref_obsolete(ref));

	/* If we've never checked the CRCs on this node, check them now */
	if (ref_flags(ref) == REF_UNCHECKED) {
		uint32_t crc, len;

		crc = crc32(0, rd, sizeof(*rd) - 8);
		if (unlikely(crc != je32_to_cpu(rd->node_crc))) {
			JFFS2_NOTICE("header CRC failed on node at %#08x: read %#08x, calculated %#08x\n",
					ref_offset(ref), je32_to_cpu(rd->node_crc), crc);
			return 1;
		}
		
		/* Sanity checks */
		if (unlikely(je32_to_cpu(rd->offset) > je32_to_cpu(rd->isize)) ||
		    unlikely(PAD(je32_to_cpu(rd->csize) + sizeof(*rd)) != PAD(je32_to_cpu(rd->totlen)))) {
				JFFS2_WARNING("inode node header CRC is corrupted at %#08x\n", ref_offset(ref));
				jffs2_dbg_dump_node(c, ref_offset(ref));
			return 1;
		}

		if (rd->compr != JFFS2_COMPR_ZERO && je32_to_cpu(rd->csize)) {
			unsigned char *buf = NULL;
			uint32_t pointed = 0;
			int err;
#ifndef __ECOS
			if (c->mtd->point) {
				err = c->mtd->point (c->mtd, ref_offset(ref) + sizeof(*rd), je32_to_cpu(rd->csize),
						     &read, &buf);
				if (unlikely(read < je32_to_cpu(rd->csize)) && likely(!err)) {
					JFFS2_ERROR("MTD point returned len too short: 0x%zx\n", read);
					c->mtd->unpoint(c->mtd, buf, ref_offset(ref) + sizeof(*rd),
							je32_to_cpu(rd->csize));
				} else if (unlikely(err)){
					JFFS2_ERROR("MTD point failed %d\n", err);
				} else
					pointed = 1; /* succefully pointed to device */
			}
#endif					
			if(!pointed){
				buf = kmalloc(je32_to_cpu(rd->csize), GFP_KERNEL);
				if (!buf)
					return -ENOMEM;
				
				err = jffs2_flash_read(c, ref_offset(ref) + sizeof(*rd), je32_to_cpu(rd->csize),
							&read, buf);
				if (unlikely(read != je32_to_cpu(rd->csize)) && likely(!err))
					err = -EIO;
				if (err) {
					kfree(buf);
					return err;
				}
			}
			crc = crc32(0, buf, je32_to_cpu(rd->csize));
			if(!pointed)
				kfree(buf);
#ifndef __ECOS
			else
				c->mtd->unpoint(c->mtd, buf, ref_offset(ref) + sizeof(*rd), je32_to_cpu(rd->csize));
#endif

			if (crc != je32_to_cpu(rd->data_crc)) {
				JFFS2_NOTICE("data CRC failed on node at %#08x: read %#08x, calculated %#08x\n",
					ref_offset(ref), je32_to_cpu(rd->data_crc), crc);
				return 1;
			}
			
		}

		/* Mark the node as having been checked and fix the accounting accordingly */
		jeb = &c->blocks[ref->flash_offset / c->sector_size];
		len = ref_totlen(c, jeb, ref);

		spin_lock(&c->erase_completion_lock);
		jeb->used_size += len;
		jeb->unchecked_size -= len;
		c->used_size += len;
		c->unchecked_size -= len;

		/* If node covers at least a whole page, or if it starts at the 
		   beginning of a page and runs to the end of the file, or if 
		   it's a hole node, mark it REF_PRISTINE, else REF_NORMAL. 

		   If it's actually overlapped, it'll get made NORMAL (or OBSOLETE) 
		   when the overlapping node(s) get added to the tree anyway. 
		*/
		if ((je32_to_cpu(rd->dsize) >= PAGE_CACHE_SIZE) ||
		    ( ((je32_to_cpu(rd->offset) & (PAGE_CACHE_SIZE-1))==0) &&
		      (je32_to_cpu(rd->dsize) + je32_to_cpu(rd->offset) == je32_to_cpu(rd->isize)))) {
			JFFS2_DBG_READINODE("marking node at %#08x REF_PRISTINE\n", ref_offset(ref));
			ref->flash_offset = ref_offset(ref) | REF_PRISTINE;
		} else {
			JFFS2_DBG_READINODE("marking node at %#08x REF_NORMAL\n", ref_offset(ref));
			ref->flash_offset = ref_offset(ref) | REF_NORMAL;
		}
		spin_unlock(&c->erase_completion_lock);
	}

	tn = jffs2_alloc_tmp_dnode_info();
	if (!tn) {
		JFFS2_ERROR("alloc tn failed\n");
		return -ENOMEM;
	}

	tn->fn = jffs2_alloc_full_dnode();
	if (!tn->fn) {
		JFFS2_ERROR("alloc fn failed\n");
		jffs2_free_tmp_dnode_info(tn);
		return -ENOMEM;
	}
	
	tn->version = je32_to_cpu(rd->version);
	tn->fn->ofs = je32_to_cpu(rd->offset);
	tn->fn->raw = ref;
	
	/* There was a bug where we wrote hole nodes out with
	   csize/dsize swapped. Deal with it */
	if (rd->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(rd->dsize) && je32_to_cpu(rd->csize))
		tn->fn->size = je32_to_cpu(rd->csize);
	else // normal case...
		tn->fn->size = je32_to_cpu(rd->dsize);

	JFFS2_DBG_READINODE("dnode @%08x: ver %u, offset %#04x, dsize %#04x\n",
		  ref_offset(ref), je32_to_cpu(rd->version), je32_to_cpu(rd->offset), je32_to_cpu(rd->dsize));
	
	jffs2_add_tn_to_tree(tn, tnp);

	return 0;
}