intrep.c

elinux jffs初始版本 具体了解JFFS的文件系统！

}


/* Used for traversing all nodes in the hash table.  */
int
jffs_foreach_file(struct jffs_control *c, int (*func)(struct jffs_file *))
{
	struct jffs_file *f;
	struct jffs_file *next_f;
	int pos;
	int r;
	int result = 0;

	for (pos = 0; pos < c->hash_len; pos++) {
		for (f = c->hash[pos]; f; f = next_f) {
			/* We need a reference to the next file in the
			   list because `func' might remove the current
			   file `f'.  */
			next_f = f->hash_next;
			if ((r = func(f)) < 0) {
				return r;
			}
			result += r;
		}
	}

	return result;
}


/* Free all memory associated with a file.  */
int
jffs_free_node_list(struct jffs_file *f)
{
	struct jffs_node *node;
	struct jffs_node *p;

	D3(printk("jffs_free_node_list(): f #%u, \"%s\"\n",
		  f->ino, (f->name ? f->name : "")));
	node = f->version_head;
	while (node) {
		p = node;
		node = node->version_next;
		kfree(p);
		DJM(no_jffs_node--);
	}
	return 0;
}


/* See if a file is deleted. If so, mark that file's nodes as obsolete.  */
int
jffs_possibly_delete_file(struct jffs_file *f)
{
	struct jffs_node *n;

	D3(printk("jffs_possibly_delete_file(): ino: %u\n",
		  f->ino));

	ASSERT(if (!f) {
		printk(KERN_ERR "jffs_possibly_delete_file(): f == NULL\n");
		return -1;
	});

	if (f->deleted) {
		/* First try to remove all older versions.  */
		for (n = f->version_head; n; n = n->version_next) {
			if (!n->fm) {
				continue;
			}
			if (jffs_fmfree(f->c->fmc, n->fm, n) < 0) {
				break;
			}
		}
		/* Unlink the file from the filesystem.  */
		jffs_unlink_file_from_tree(f);
		jffs_unlink_file_from_hash(f);
		jffs_free_node_list(f);
		if (f->name) {
			kfree(f->name);
			DJM(no_name--);
		}
		kfree(f);
		DJM(no_jffs_file--);
	}
	return 0;
}


/* Used in conjunction with jffs_foreach_file() to count the number
   of files in the file system.  */
int
jffs_file_count(struct jffs_file *f)
{
	return 1;
}


/* Build up a file's range list from scratch by going through the
   version list.  */
int
jffs_build_file(struct jffs_file *f)
{
	struct jffs_node *n;

	D3(printk("jffs_build_file(): ino: %u, name: \"%s\"\n",
		  f->ino, (f->name ? f->name : "")));

	for (n = f->version_head; n; n = n->version_next) {
		jffs_update_file(f, n);
	}
	return 0;
}


/* Remove an amount of data from a file. If this amount of data is
   zero, that could mean that a node should be split in two parts.
   We remove or change the appropriate nodes in the lists.

   Starting offset of area to be removed is node->data_offset,
   and the length of the area is in node->removed_size.   */
static void
jffs_delete_data(struct jffs_file *f, struct jffs_node *node)
{
	struct jffs_node *n;
	__u32 offset = node->data_offset;
	__u32 remove_size = node->removed_size;

	D3(printk("jffs_delete_data(): offset = %u, remove_size = %u\n",
		  offset, remove_size));

	if (remove_size == 0
	    && f->range_tail
	    && f->range_tail->data_offset + f->range_tail->data_size
	       == offset) {
		/* A simple append; nothing to remove or no node to split.  */
		return;
	}

	/* Find the node where we should begin the removal.  */
	for (n = f->range_head; n; n = n->range_next) {
		if (n->data_offset + n->data_size > offset) {
			break;
		}
	}
	if (!n) {
		/* If there's no data in the file there's no data to
		   remove either.  */
		return;
	}

	if (n->data_offset > offset) {
		/* XXX: Not implemented yet.  */
		printk(KERN_WARNING "JFFS: An unexpected situation "
		       "occurred in jffs_delete_data.\n");
	}
	else if (n->data_offset < offset) {
		/* See if the node has to be split into two parts.  */
		if (n->data_offset + n->data_size < offset + remove_size) {
			/* Do the split.  */
			struct jffs_node *new_node;
			D3(printk("jffs_delete_data(): Split node with "
				  "version number %u.\n", n->version));

			if (!(new_node = (struct jffs_node *)
					 kmalloc(sizeof(struct jffs_node),
						 GFP_KERNEL))) {
				D(printk("jffs_delete_data(): -ENOMEM\n"));
				return;
			}
			DJM(no_jffs_node++);

			new_node->ino = n->ino;
			new_node->version = n->version;
			new_node->data_offset = offset;
			new_node->data_size = n->data_size
					      - (remove_size
						 + (offset - n->data_offset));
			new_node->fm_offset = n->fm_offset + n->data_size
					      + remove_size;
			new_node->name_size = n->name_size;
			new_node->fm = n->fm;
			new_node->version_prev = n;
			new_node->version_next = n->version_next;
			if (new_node->version_next) {
				new_node->version_next->version_prev
				= new_node;
			}
			else {
				f->version_tail = new_node;
			}
			n->version_next = new_node;
			new_node->range_prev = n;
			new_node->range_next = n->range_next;
			if (new_node->range_next) {
				new_node->range_next->range_prev = new_node;
			}
			else {
				f->range_tail = new_node;
			}
			/* A very interesting can of worms.  */
			n->range_next = new_node;
			n->data_size = offset - n->data_offset;
			jffs_add_node(new_node);
			n = new_node->range_next;
			remove_size = 0;
		}
		else {
			/* No.  No need to split the node.  Just remove
			   the end of the node.  */
			int r = jffs_min(n->data_offset + n->data_size
					 - offset, remove_size);
			n->data_size -= r;
			remove_size -= r;
			n = n->range_next;
		}
	}

	/* Remove as many nodes as necessary.  */
	while (n && remove_size) {
		if (n->data_size <= remove_size) {
			struct jffs_node *p = n;
			remove_size -= n->data_size;
			n = n->range_next;
			D3(printk("jffs_delete_data(): Removing node: "
				  "ino: %u, version: %u\n",
				  p->ino, p->version));
			if (p->fm) {
				jffs_fmfree(f->c->fmc, p->fm, p);
			}
			jffs_unlink_node_from_range_list(f, p);
			jffs_unlink_node_from_version_list(f, p);
			kfree(p);
			DJM(no_jffs_node--);
		}
		else {
			n->data_size -= remove_size;
			n->fm_offset += remove_size;
			n->data_offset -= (node->removed_size - remove_size);
			n = n->range_next;
			break;
		}
	}

	/* Adjust the following nodes' information about offsets etc.  */
	while (n && node->removed_size) {
		n->data_offset -= node->removed_size;
		n = n->range_next;
	}

	f->size -= node->removed_size;
	D3(printk("jffs_delete_data(): f->size = %d\n", f->size));
} /* jffs_delete_data()  */


/* Insert some data into a file.  Prior to the call to this function,
   jffs_delete_data() should be called.  */
static void
jffs_insert_data(struct jffs_file *f, struct jffs_node *node)
{
	D3(printk("jffs_insert_data(): node->data_offset = %u, "
		  "node->data_size = %u, f->size = %u\n",
		  node->data_offset, node->data_size, f->size));

	/* Find the position where we should insert data.  */

	if (node->data_offset == f->size) {
		/* A simple append.  This is the most common operation.  */
		node->range_next = 0;
		node->range_prev = f->range_tail;
		if (node->range_prev) {
			node->range_prev->range_next = node;
		}
		f->range_tail = node;
		f->size += node->data_size;
		if (!f->range_head) {
			f->range_head = node;
		}
	}
	else if (node->data_offset < f->size) {
		/* Trying to insert data into the middle of the file.  This
		   means no problem because jffs_delete_data() has already
		   prepared the range list for us.  */
		struct jffs_node *n;

		/* Find the correct place for the insertion and then insert
		   the node.  */
		for (n = f->range_head; n; n = n->range_next) {
			D1(printk("Cool stuff's happening!\n"));

			if (n->data_offset == node->data_offset) {
				node->range_prev = n->range_prev;
				if (node->range_prev) {
					node->range_prev->range_next = node;
				}
				else {
					f->range_head = node;
				}
				node->range_next = n;
				n->range_prev = node;
				break;
			}
			ASSERT(else if (n->data_offset + n->data_size >
					node->data_offset) {
				printk(KERN_ERR "jffs_insert_data(): "
				       "Couldn't find a place to insert "
				       "the data!\n");
				return;
			});
		}

		/* Adjust later nodes' offsets etc.  */
		n = node->range_next;
		while (n) {
			n->data_offset += node->data_size;
			n = n->range_next;
		}
		f->size += node->data_size;
	}
	else if (node->data_offset > f->size) {
		/* Not implemented yet.  */
#if 0
		/* Below is some example code for future use if we decide
		   to implement it.  */
		/* This is code that isn't supported by VFS. So there aren't
		   really any reasons to implement it yet.  */
		if (!f->range_head) {
			if (node->data_offset > f->size) {
				if (!(nn = jffs_alloc_node())) {
					D(printk("jffs_insert_data(): "
						 "Allocation failed.\n"));
					return;
				}
				nn->version = JFFS_MAGIC_BITMASK;
				nn->data_offset = 0;
				nn->data_size = node->data_offset;
				nn->removed_size = 0;
				nn->fm_offset = 0;
				nn->name_size = 0;
				nn->fm = 0; /* This is a virtual data holder.  */
				nn->version_prev = 0;
				nn->version_next = 0;
				nn->range_prev = 0;
				nn->range_next = 0;
				nh->range_head = nn;
				nh->range_tail = nn;
			}
		}
#endif
	}

	D3(printk("jffs_insert_data(): f->size = %d\n", f->size));
}


/* A new node (with data) has been added to the file and now the range
   list has to be modified.  */
static int
jffs_update_file(struct jffs_file *f, struct jffs_node *node)
{
	D3(printk("jffs_update_file(): ino: %u, version: %u\n",
		  f->ino, node->version));

	if (node->data_size == 0) {
		if (node->removed_size == 0) {
			/* data_offset == X  */
			/* data_size == 0  */
			/* remove_size == 0  */
		}
		else {
			/* data_offset == X  */
			/* data_size == 0  */
			/* remove_size != 0  */
			jffs_delete_data(f, node);
		}
	}
	else {
		/* data_offset == X  */
		/* data_size != 0  */
		/* remove_size == Y  */
		jffs_delete_data(f, node);
		jffs_insert_data(f, node);
	}
	return 0;
}


/* Print the contents of a node.  */
void
jffs_print_node(struct jffs_node *n)
{
	D(printk("jffs_node: 0x%p\n", n));
	D(printk("{\n"));
	D(printk("        0x%08x, /* version  */\n", n->version));
	D(printk("        0x%08x, /* data_offset  */\n", n->data_offset));
	D(printk("        0x%08x, /* data_size  */\n", n->data_size));
	D(printk("        0x%08x, /* removed_size  */\n", n->removed_size));
	D(printk("        0x%08x, /* fm_offset  */\n", n->fm_offset));
	D(printk("        0x%02x,       /* name_size  */\n", n->name_size));
	D(printk("        0x%p, /* fm,  fm->offset: %u  */\n",
		 n->fm, n->fm->offset));
	D(printk("        0x%p, /* version_prev  */\n", n->version_prev));
	D(printk("        0x%p, /* version_next  */\n", n->version_next));
	D(printk("        0x%p, /* range_prev  */\n", n->range_prev));
	D(printk("        0x%p, /* range_next  */\n", n->range_next));
	D(printk("}\n"));
}


/* Print the contents of a raw inode.  */
void
jffs_print_raw_inode(struct jffs_raw_inode *raw_inode)
{
	D(printk("jffs_raw_inode: inode number: %u\n", raw_inode->ino));
	D(printk("{\n"));
	D(printk("        0x%08x, /* magic  */\n", raw_inode->magic));
	D(printk("        0x%08x, /* ino  */\n", raw_inode->ino));
	D(printk("        0x%08x, /* pino  */\n", raw_inode->pino));
	D(printk("        0x%08x, /* version  */\n", raw_inode->version));
	D(printk("        0x%08x, /* mode  */\n", raw_inode->mode));
	D(printk("        0x%04x,     /* uid  */\n", raw_inode->uid));
	D(printk("        0x%04x,     /* gid  */\n", raw_inode->gid));
	D(printk("        0x%08x, /* atime  */\n", raw_inode->atime));
	D(printk("        0x%08x, /* mtime  */\n", raw_inode->mtime));
	D(printk("        0x%08x, /* ctime  */\n", raw_inode->ctime));
	D(printk("        0x%08x, /* offset  */\n", raw_inode->offset));
	D(printk("        0x%08x, /* dsize  */\n", raw_inode->dsize));
	D(printk("        0x%08x, /* rsize  */\n", raw_inode->rsize));
	D(printk("        0x%02x,       /* nsize  */\n", raw_inode->nsize));
	D(printk("        0x%02x,       /* nlink  */\n", raw_inode->nlink));
	D(printk("        0x%02x,       /* spare  */\n",
		 raw_inode->spare));
	D(printk("        %u,          /* rename  */\n",
		 raw_inode->rename));
	D(printk("        %u,          /* deleted  */\n",
		 raw_inode->deleted));
	D(printk("        0x%02x,       /* accurate  */\n",
		 raw_inode->accurate));
	D(printk("        0x%08x, /* dchksum  */\n", raw_inode->dchksum));
	D(printk("        0x%04x,     /* nchksum  */\n", raw_inode->nchksum));
	D(printk("        0x%04x,     /* chksum  */\n", raw_inode->chksum));
	D(printk("}\n"));
}


/* Print the contents of a file.  */
int
jffs_print_file(struct jffs_file *f)
{
	D(int i);
	D(printk("jffs_file: 0x%p\n", f));
	D(printk("{\n"));
	D(printk("        0x%08x, /* ino  */\n", f->ino));
	D(printk("        0x%08x, /* pino  */\n", f->pino));
	D(printk("        0x%08x, /* mode  */\n", f->mode));
	D(printk("        0x%04x,     /* uid  */\n", f->uid));
	D(printk("        0x%04x,     /* gid  */\n", f->gid));
	D(printk("        0x%08x, /* atime  */\n", f->atime));
	D(printk("        0x%08x, /* mtime  */\n", f->mtime));
	D(printk("        0x%08x, /* ctime  */\n", f->ctime));
	D(printk("        0x%02x,       /* nsize  */\n", f->nsize));
	D(printk("        0x%02x,       /* nlink  */\n", f->nlink));
	D(printk("        0x%02x,       /* deleted  */\n", f->deleted));
	D(printk("        \"%s\", ", (f->name ? f->name : "")));
	D(for (i = strlen(f->name ? f->name : ""); i < 8; ++i) {
		printk(" ");
	});
	D(printk("/* name  */\n"));
	D(printk("        0x%08x, /* size  */\n", f->size));
	D(printk("        0x%08x, /* highest_version  */\n",
		 f->highest_version));
	D(printk("        0x%p, /* c  */\n", f->c));
	D(printk("        0x%p, /* parent  */\n", f->parent));
	D(printk("        0x%p, /* children  */\n", f->children));
	D(printk("        0x%p, /* sibling_prev  */\n", f->sibling_prev));
	D(printk("        0x%p, /* sibling_next  */\n", f->sibling_next));
	D(printk("        0x%p, /* hash_prev  */\n", f->hash_prev));
	D(printk("        0x%p, /* hash_next  */\n", f->hash_next));
	D(printk("        0x%p, /* range_head  */\n", f->range_head));
	D(printk("        0x%p, /* range_tail  */\n", f->range_tail));
	D(printk("        0x%p, /* version_head  */\n", f->version_head));
	D(printk("