intrep.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

		 * collection.
		 *
		 * If this is the case, don't let f->size go negative.
		 * Bad things would happen :)
		 */
		f->size = node->data_offset;
	} else {
		f->size -= node->removed_size;
	}
	D3(printk("jffs_delete_data(): f->size = %d\n", f->size));
	return 0;
} /* jffs_delete_data()  */


/* Insert some data into a file.  Prior to the call to this function,
   jffs_delete_data should be called.  */
static int
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.  */
	retry:
	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) {
			D2(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 -1;
			});
		}

		/* 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) {
		/* Okay.  This is tricky.  This means that we want to insert
		   data at a place that is beyond the limits of the file as
		   it is constructed right now.  This is actually a common
		   event that for instance could occur during the mounting
		   of the file system if a large file have been truncated,
		   rewritten and then only partially garbage collected.  */

		struct jffs_node *n;

		/* We need a place holder for the data that is missing in
		   front of this insertion.  This "virtual node" will not
		   be associated with any space on the flash device.  */
		struct jffs_node *virtual_node;
		if (!(virtual_node = (struct jffs_node *)
				     kmalloc(sizeof(struct jffs_node),
					     GFP_KERNEL))) {
			return -ENOMEM;
		}

		D(printk("jffs_insert_data: Inserting a virtual node.\n"));
		D(printk("  node->data_offset = %u\n", node->data_offset));
		D(printk("  f->size = %u\n", f->size));

		virtual_node->ino = node->ino;
		virtual_node->version = node->version;
		virtual_node->removed_size = 0;
		virtual_node->fm_offset = 0;
		virtual_node->name_size = 0;
		virtual_node->fm = 0; /* This is a virtual data holder.  */
		virtual_node->version_prev = 0;
		virtual_node->version_next = 0;
		virtual_node->range_next = 0;

		/* Are there any data at all in the file yet?  */
		if (f->range_head) {
			virtual_node->data_offset
			= f->range_tail->data_offset
			  + f->range_tail->data_size;
			virtual_node->data_size
			= node->data_offset - virtual_node->data_offset;
			virtual_node->range_prev = f->range_tail;
			f->range_tail->range_next = virtual_node;
		}
		else {
			virtual_node->data_offset = 0;
			virtual_node->data_size = node->data_offset;
			virtual_node->range_prev = 0;
			f->range_head = virtual_node;
		}

		f->range_tail = virtual_node;
		f->size += virtual_node->data_size;

		/* Insert this virtual node in the version list as well.  */
		for (n = f->version_head; n ; n = n->version_next) {
			if (n->version == virtual_node->version) {
				virtual_node->version_prev = n->version_prev;
				n->version_prev = virtual_node;
				if (virtual_node->version_prev) {
					virtual_node->version_prev
					->version_next = virtual_node;
				}
				else {
					f->version_head = virtual_node;
				}
				virtual_node->version_next = n;
				break;
			}
		}

		D(jffs_print_node(virtual_node));

		/* Make a new try to insert the node.  */
		goto retry;
	}

	D3(printk("jffs_insert_data(): f->size = %d\n", f->size));
	return 0;
}


/* 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)
{
	int err;

	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  */
			if ((err = jffs_delete_data(f, node)) < 0) {
				return err;
			}
		}
	}
	else {
		/* data_offset == X  */
		/* data_size != 0  */
		/* remove_size == Y  */
		if ((err = jffs_delete_data(f, node)) < 0) {
			return err;
		}
		if ((err = jffs_insert_data(f, node)) < 0) {
			return err;
		}
	}
	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 ? n->fm->offset : 0)));
	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("        0x%p, /* version_tail  */\n", f->version_tail));
	D(printk("}\n"));
	return 0;
}


void
jffs_print_hash_table(struct jffs_control *c)
{
	int i;

	printk("JFFS: Dumping the file system's hash table...\n");
	for (i = 0; i < c->hash_len; i++) {
		struct list_head *p;
		for (p = c->hash[i].next; p != &c->hash[i]; p = p->next) {
			struct jffs_file *f=list_entry(p,struct jffs_file,hash);
			printk("*** c->hash[%u]: \"%s\" "
			       "(ino: %u, pino: %u)\n",
			       i, (f->name ? f->name : ""),
			       f->ino, f->pino);
		}
	}
}


void
jffs_print_tree(struct jffs_file *first_file, int indent)
{
	struct jffs_file *f;
	char *space;
	int dir;

	if (!first_file) {
		return;
	}

	if (!(space = (char *) kmalloc(indent + 1, GFP_KERNEL))) {
		printk("jffs_print_tree(): Out of memory!\n");
		return;
	}

	memset(space, ' ', indent);
	space[indent] = '\0';

	for (f = first_file; f; f = f->sibling_next) {
		dir = S_ISDIR(f->mode);
		printk("%s%s%s (ino: %u, highest_version: %u, size: %u)\n",
		       space, (f->name ? f->name : ""), (dir ? "/" : ""),
		       f->ino, f->highest_version, f->size);
		if (dir) {
			jffs_print_tree(f->children, indent + 2);
		}
	}

	kfree(space);
}


#if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG
void
jffs_print_memory_allocation_statistics(void)
{
	static long printout = 0;
	printk("________ Memory printout #%ld ________\n", ++printout);
	printk("no_jffs_file = %ld\n", no_jffs_file);
	printk("no_jffs_node = %ld\n", no_jffs_node);
	printk("no_jffs_control = %ld\n", no_jffs_control);
	printk("no_jffs_raw_inode = %ld\n", no_jffs_raw_inode);
	printk("no_jffs_node_ref = %ld\n", no_jffs_node_ref);
	printk("no_jffs_fm = %ld\n", no_jffs_fm);
	printk("no_jffs_fmcontrol = %ld\n", no_jffs_fmcontrol);
	printk("no_hash = %ld\n", no_hash);
	printk("no_name = %ld\n", no_name);
	printk("\n");
}
#endif


/* Rewrite `size' bytes, and begin at `node'.  */
int
jffs_rewrite_data(struct jffs_file *f, struct jffs_node *node, int size)
{
	struct jffs_control *c = f->c;
	struct jffs_fmcontrol *fmc = c->fmc;
	struct jffs_raw_inode raw_inode;
	struct jffs_node *new_node;
	struct jffs_fm *fm;
	__u32 pos;
	__u32 pos_dchksum;
	__u32 total_name_size;
	__u32 total_data_size;
	__u32 total_size;
	int err;

	D1(printk("***jffs_rewrite_data(): node: %u, name: \"%s\", size: %u\n",
		  f->ino, (f->name ? f->name : "(null)"), size));

	/* Create and initialize the new node.  */
	if (!(new_node = (struct jffs_node *)
			 kmalloc(sizeof(struct jffs_node), GFP_KERNEL))) {
		D(printk("jffs_rewrite_data(): "
			 "Failed to allocate node.\n"));
		return -ENOMEM;
	}
	DJM(no_jffs_node++);
	new_node->data_offset = node->data_offset;
	new_node->removed_size = size;
	total_name_size = JFFS_PAD(f->nsize);
	total_data_size = JFFS_PAD(size);
	total_size = sizeof(struct jffs_raw_inode)
		     + total_name_size + total_data_size;
	new_node->fm_offset = sizeof(struct jffs_raw_inode)
			      + total_name_size;

	jffs_fm_write_lock(fmc);

	if ((err = jffs_fmalloc(fmc, total_size, new_node, &fm)) < 0) {
		DJM(no_jffs_node--);
		jffs_fm_write_unlock(fmc);
		D(printk("jffs_rewrite_data(): Failed to allocate fm.\n"));
		kfree(new_node);
		return err;
	}
	else if (!fm->nodes) {
		/* The jffs_fm struct that we got is not big enough.  */
		/* This should never happen, because we deal with this case
		   in jffs_garbage_collect_next().*/
		printk(KERN_WARNING "jffs_rewrite_data(): Allocated node is too small (%d bytes of %d)\n", fm->size, total_size);
		if ((err = jffs_write_dummy_node(c, fm)) < 0) {
			D(printk("jffs_rewrite_data(): "
				 "jffs_write_dummy_node() Failed!\n"));
		} else {
			err = -ENOSPC;
		}
		DJM(no_jffs_fm--);
		jffs_fm_write_unlock(fmc);
		kfree(fm);
		
		return err;
	}
	new_node->fm = fm;

	/* Initialize the raw inode.  */
	raw_inode.magic = JFFS_MAGIC_BITMASK;
	raw_inode.ino = f->ino;
	raw_inode.pino = f->pino;
	raw_inode.version = f->highest_version + 1;
	raw_inode.mode = f->mode;
	raw_inode.uid = f->uid;
	raw_inode.gid = f->gid;
	raw_inode.atime = f->atime;
	raw_inode.mtime = f->mtime;
	raw_inode.ctime = f->ctime;
	raw_inode.offset = node->data_offset;
	raw_inode.dsize = size;
	raw_inode.rsize = size;
	raw_inode.nsize = f->nsize;
	raw_inode.nlink = f->nlink;
	raw_inode.spare = 0;
	raw_inode.rename = 0;
	raw_inode.deleted = 0;
	raw_inode.accurate = 0xff;
	raw_inode.dchksum = 0;
	raw_inode.nchksum = 0;

	pos = new_node->fm->offset;
	pos_dchksum = pos +JFFS_RAW_INODE_DCHKSUM_OFFSET;

	D3(printk("jffs_rewrite_data(): Writing this raw inode "
		  "to pos 0x%ul.\n", pos));
	D3(jffs_print_raw_inode(&raw_inode));

	if ((err = flash_safe_write(fmc->mtd, pos,
				    (u_char *) &raw_inode,
				    sizeof(struct jffs_raw_inode)
				    - sizeof(__u32)
				    - sizeof(__u16) - sizeof(__u16))) < 0) {
		jffs_fmfree_partly(fmc, fm,
				   total_name_size + total_data_size);
		jffs_fm_write_unlock(fmc);
		printk(KERN_ERR "JFFS: jffs_rewrite_data: Write error during "
		       "rewrite. (raw inode)\n");
		return err;
	}
	pos += sizeof(struct jffs_raw_inode);

	/* Write the name to the flash memory.  */
	if (f->nsize) {
		D3(printk("jffs_rewrite_data(): Writing name \"%s\" to "
			  "pos 0x%ul.\n", f->name, (long)pos));
		if ((err = flash_safe_write(fmc->mtd, pos,
					    (u_char *)f->name,
					    f->nsize)) < 0) {
			jffs_fmfree_partly(fmc, fm, total_data_size);