scan.c

linux 内核源代码

			continue;
		}

		switch(je16_to_cpu(node->nodetype)) {
		case JFFS2_NODETYPE_INODE:
			if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
				buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
				D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
					  sizeof(struct jffs2_raw_inode), buf_len, ofs));
				err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
				if (err)
					return err;
				buf_ofs = ofs;
				node = (void *)buf;
			}
			err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
			if (err) return err;
			ofs += PAD(je32_to_cpu(node->totlen));
			break;

		case JFFS2_NODETYPE_DIRENT:
			if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
				buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
				D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
					  je32_to_cpu(node->totlen), buf_len, ofs));
				err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
				if (err)
					return err;
				buf_ofs = ofs;
				node = (void *)buf;
			}
			err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
			if (err) return err;
			ofs += PAD(je32_to_cpu(node->totlen));
			break;

#ifdef CONFIG_JFFS2_FS_XATTR
		case JFFS2_NODETYPE_XATTR:
			if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
				buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
				D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
					  " left to end of buf. Reading 0x%x at 0x%08x\n",
					  je32_to_cpu(node->totlen), buf_len, ofs));
				err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
				if (err)
					return err;
				buf_ofs = ofs;
				node = (void *)buf;
			}
			err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
			if (err)
				return err;
			ofs += PAD(je32_to_cpu(node->totlen));
			break;
		case JFFS2_NODETYPE_XREF:
			if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
				buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
				D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
					  " left to end of buf. Reading 0x%x at 0x%08x\n",
					  je32_to_cpu(node->totlen), buf_len, ofs));
				err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
				if (err)
					return err;
				buf_ofs = ofs;
				node = (void *)buf;
			}
			err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
			if (err)
				return err;
			ofs += PAD(je32_to_cpu(node->totlen));
			break;
#endif	/* CONFIG_JFFS2_FS_XATTR */

		case JFFS2_NODETYPE_CLEANMARKER:
			D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
			if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
				printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
				       ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
				if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
					return err;
				ofs += PAD(sizeof(struct jffs2_unknown_node));
			} else if (jeb->first_node) {
				printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
				if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
					return err;
				ofs += PAD(sizeof(struct jffs2_unknown_node));
			} else {
				jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);

				ofs += PAD(c->cleanmarker_size);
			}
			break;

		case JFFS2_NODETYPE_PADDING:
			if (jffs2_sum_active())
				jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
			if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
				return err;
			ofs += PAD(je32_to_cpu(node->totlen));
			break;

		default:
			switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
			case JFFS2_FEATURE_ROCOMPAT:
				printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
				c->flags |= JFFS2_SB_FLAG_RO;
				if (!(jffs2_is_readonly(c)))
					return -EROFS;
				if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
					return err;
				ofs += PAD(je32_to_cpu(node->totlen));
				break;

			case JFFS2_FEATURE_INCOMPAT:
				printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
				return -EINVAL;

			case JFFS2_FEATURE_RWCOMPAT_DELETE:
				D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
				if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
					return err;
				ofs += PAD(je32_to_cpu(node->totlen));
				break;

			case JFFS2_FEATURE_RWCOMPAT_COPY: {
				D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));

				jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);

				/* We can't summarise nodes we don't grok */
				jffs2_sum_disable_collecting(s);
				ofs += PAD(je32_to_cpu(node->totlen));
				break;
				}
			}
		}
	}

	if (jffs2_sum_active()) {
		if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
			dbg_summary("There is not enough space for "
				"summary information, disabling for this jeb!\n");
			jffs2_sum_disable_collecting(s);
		}
	}

	D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
		  jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size));
	
	/* mark_node_obsolete can add to wasted !! */
	if (jeb->wasted_size) {
		jeb->dirty_size += jeb->wasted_size;
		c->dirty_size += jeb->wasted_size;
		c->wasted_size -= jeb->wasted_size;
		jeb->wasted_size = 0;
	}

	return jffs2_scan_classify_jeb(c, jeb);
}

struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
{
	struct jffs2_inode_cache *ic;

	ic = jffs2_get_ino_cache(c, ino);
	if (ic)
		return ic;

	if (ino > c->highest_ino)
		c->highest_ino = ino;

	ic = jffs2_alloc_inode_cache();
	if (!ic) {
		printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
		return NULL;
	}
	memset(ic, 0, sizeof(*ic));

	ic->ino = ino;
	ic->nodes = (void *)ic;
	jffs2_add_ino_cache(c, ic);
	if (ino == 1)
		ic->nlink = 1;
	return ic;
}

static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
{
	struct jffs2_inode_cache *ic;
	uint32_t crc, ino = je32_to_cpu(ri->ino);

	D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));

	/* We do very little here now. Just check the ino# to which we should attribute
	   this node; we can do all the CRC checking etc. later. There's a tradeoff here --
	   we used to scan the flash once only, reading everything we want from it into
	   memory, then building all our in-core data structures and freeing the extra
	   information. Now we allow the first part of the mount to complete a lot quicker,
	   but we have to go _back_ to the flash in order to finish the CRC checking, etc.
	   Which means that the _full_ amount of time to get to proper write mode with GC
	   operational may actually be _longer_ than before. Sucks to be me. */

	/* Check the node CRC in any case. */
	crc = crc32(0, ri, sizeof(*ri)-8);
	if (crc != je32_to_cpu(ri->node_crc)) {
		printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on "
		       "node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
		       ofs, je32_to_cpu(ri->node_crc), crc);
		/*
		 * We believe totlen because the CRC on the node
		 * _header_ was OK, just the node itself failed.
		 */
		return jffs2_scan_dirty_space(c, jeb,
					      PAD(je32_to_cpu(ri->totlen)));
	}

	ic = jffs2_get_ino_cache(c, ino);
	if (!ic) {
		ic = jffs2_scan_make_ino_cache(c, ino);
		if (!ic)
			return -ENOMEM;
	}

	/* Wheee. It worked */
	jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);

	D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
		  je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
		  je32_to_cpu(ri->offset),
		  je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));

	pseudo_random += je32_to_cpu(ri->version);

	if (jffs2_sum_active()) {
		jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
	}

	return 0;
}

static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
{
	struct jffs2_full_dirent *fd;
	struct jffs2_inode_cache *ic;
	uint32_t checkedlen;
	uint32_t crc;
	int err;

	D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));

	/* We don't get here unless the node is still valid, so we don't have to
	   mask in the ACCURATE bit any more. */
	crc = crc32(0, rd, sizeof(*rd)-8);

	if (crc != je32_to_cpu(rd->node_crc)) {
		printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
		       ofs, je32_to_cpu(rd->node_crc), crc);
		/* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
		if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
			return err;
		return 0;
	}

	pseudo_random += je32_to_cpu(rd->version);

	/* Should never happen. Did. (OLPC trac #4184)*/
	checkedlen = strnlen(rd->name, rd->nsize);
	if (checkedlen < rd->nsize) {
		printk(KERN_ERR "Dirent at %08x has zeroes in name. Truncating to %d chars\n",
		       ofs, checkedlen);
	}
	fd = jffs2_alloc_full_dirent(checkedlen+1);
	if (!fd) {
		return -ENOMEM;
	}
	memcpy(&fd->name, rd->name, checkedlen);
	fd->name[checkedlen] = 0;

	crc = crc32(0, fd->name, rd->nsize);
	if (crc != je32_to_cpu(rd->name_crc)) {
		printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
		       ofs, je32_to_cpu(rd->name_crc), crc);
		D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
		jffs2_free_full_dirent(fd);
		/* FIXME: Why do we believe totlen? */
		/* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
		if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
			return err;
		return 0;
	}
	ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
	if (!ic) {
		jffs2_free_full_dirent(fd);
		return -ENOMEM;
	}

	fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
				      PAD(je32_to_cpu(rd->totlen)), ic);

	fd->next = NULL;
	fd->version = je32_to_cpu(rd->version);
	fd->ino = je32_to_cpu(rd->ino);
	fd->nhash = full_name_hash(fd->name, checkedlen);
	fd->type = rd->type;
	jffs2_add_fd_to_list(c, fd, &ic->scan_dents);

	if (jffs2_sum_active()) {
		jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
	}

	return 0;
}

static int count_list(struct list_head *l)
{
	uint32_t count = 0;
	struct list_head *tmp;

	list_for_each(tmp, l) {
		count++;
	}
	return count;
}

/* Note: This breaks if list_empty(head). I don't care. You
   might, if you copy this code and use it elsewhere :) */
static void rotate_list(struct list_head *head, uint32_t count)
{
	struct list_head *n = head->next;

	list_del(head);
	while(count--) {
		n = n->next;
	}
	list_add(head, n);
}

void jffs2_rotate_lists(struct jffs2_sb_info *c)
{
	uint32_t x;
	uint32_t rotateby;

	x = count_list(&c->clean_list);
	if (x) {
		rotateby = pseudo_random % x;
		rotate_list((&c->clean_list), rotateby);
	}

	x = count_list(&c->very_dirty_list);
	if (x) {
		rotateby = pseudo_random % x;
		rotate_list((&c->very_dirty_list), rotateby);
	}

	x = count_list(&c->dirty_list);
	if (x) {
		rotateby = pseudo_random % x;
		rotate_list((&c->dirty_list), rotateby);
	}

	x = count_list(&c->erasable_list);
	if (x) {
		rotateby = pseudo_random % x;
		rotate_list((&c->erasable_list), rotateby);
	}

	if (c->nr_erasing_blocks) {
		rotateby = pseudo_random % c->nr_erasing_blocks;
		rotate_list((&c->erase_pending_list), rotateby);
	}

	if (c->nr_free_blocks) {
		rotateby = pseudo_random % c->nr_free_blocks;
		rotate_list((&c->free_list), rotateby);
	}
}