C++ JFFS2_INODE_INFO函数代码示例

static int jffs2_mkdir (struct inode *dir_i, struct dentry *dentry, int mode)
{
	struct jffs2_inode_info *f, *dir_f;
	struct jffs2_sb_info *c;
	struct inode *inode;
	struct jffs2_raw_inode *ri;
	struct jffs2_raw_dirent *rd;
	struct jffs2_full_dnode *fn;
	struct jffs2_full_dirent *fd;
	int namelen;
	uint32_t alloclen, phys_ofs;
	int ret;

	mode |= S_IFDIR;

	ri = jffs2_alloc_raw_inode();
	if (!ri)
		return -ENOMEM;
	
	c = JFFS2_SB_INFO(dir_i->i_sb);

	/* Try to reserve enough space for both node and dirent. 
	 * Just the node will do for now, though 
	 */
	namelen = dentry->d_name.len;
	ret = jffs2_reserve_space(c, sizeof(*ri), &phys_ofs, &alloclen, ALLOC_NORMAL);

	if (ret) {
		jffs2_free_raw_inode(ri);
		return ret;
	}

	inode = jffs2_new_inode(dir_i, mode, ri);

	if (IS_ERR(inode)) {
		jffs2_free_raw_inode(ri);
		jffs2_complete_reservation(c);
		return PTR_ERR(inode);
	}

	inode->i_op = &jffs2_dir_inode_operations;
	inode->i_fop = &jffs2_dir_operations;
	/* Directories get nlink 2 at start */
	inode->i_nlink = 2;

	f = JFFS2_INODE_INFO(inode);

	ri->data_crc = cpu_to_je32(0);
	ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));
	
	fn = jffs2_write_dnode(c, f, ri, NULL, 0, phys_ofs, ALLOC_NORMAL);

	jffs2_free_raw_inode(ri);

	if (IS_ERR(fn)) {
		/* Eeek. Wave bye bye */
		up(&f->sem);
		jffs2_complete_reservation(c);
		jffs2_clear_inode(inode);
		return PTR_ERR(fn);
	}
	/* No data here. Only a metadata node, which will be 
	   obsoleted by the first data write
	*/
	f->metadata = fn;
	up(&f->sem);

	jffs2_complete_reservation(c);
	ret = jffs2_reserve_space(c, sizeof(*rd)+namelen, &phys_ofs, &alloclen, ALLOC_NORMAL);
	if (ret) {
		/* Eep. */
		jffs2_clear_inode(inode);
		return ret;
	}
	
	rd = jffs2_alloc_raw_dirent();
	if (!rd) {
		/* Argh. Now we treat it like a normal delete */
		jffs2_complete_reservation(c);
		jffs2_clear_inode(inode);
		return -ENOMEM;
	}

	dir_f = JFFS2_INODE_INFO(dir_i);
	down(&dir_f->sem);

	rd->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
	rd->nodetype = cpu_to_je16(JFFS2_NODETYPE_DIRENT);
	rd->totlen = cpu_to_je32(sizeof(*rd) + namelen);
	rd->hdr_crc = cpu_to_je32(crc32(0, rd, sizeof(struct jffs2_unknown_node)-4));

	rd->pino = cpu_to_je32(dir_i->i_ino);
	rd->version = cpu_to_je32(++dir_f->highest_version);
	rd->ino = cpu_to_je32(inode->i_ino);
	rd->mctime = cpu_to_je32(get_seconds());
	rd->nsize = namelen;
	rd->type = DT_DIR;
	rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8));
	rd->name_crc = cpu_to_je32(crc32(0, dentry->d_name.name, namelen));

//.........这里部分代码省略.........

static int jffs2_write_end(struct file *filp, struct address_space *mapping,
			loff_t pos, unsigned len, unsigned copied,
			struct page *pg, void *fsdata)
{
	/* Actually commit the write from the page cache page we're looking at.
	 * For now, we write the full page out each time. It sucks, but it's simple
	 */
	struct inode *inode = mapping->host;
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	struct jffs2_raw_inode *ri;
	unsigned start = pos & (PAGE_CACHE_SIZE - 1);
	unsigned end = start + copied;
	unsigned aligned_start = start & ~3;
	int ret = 0;
	uint32_t writtenlen = 0;

	D1(printk(KERN_DEBUG "jffs2_write_end(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
		  inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));

	/* We need to avoid deadlock with page_cache_read() in
	   jffs2_garbage_collect_pass(). So the page must be
	   up to date to prevent page_cache_read() from trying
	   to re-lock it. */
	BUG_ON(!PageUptodate(pg));

	if (end == PAGE_CACHE_SIZE) {
		/* When writing out the end of a page, write out the
		   _whole_ page. This helps to reduce the number of
		   nodes in files which have many short writes, like
		   syslog files. */
		aligned_start = 0;
	}

	ri = jffs2_alloc_raw_inode();

	if (!ri) {
		D1(printk(KERN_DEBUG "jffs2_write_end(): Allocation of raw inode failed\n"));
		unlock_page(pg);
		page_cache_release(pg);
		return -ENOMEM;
	}

	/* Set the fields that the generic jffs2_write_inode_range() code can't find */
	ri->ino = cpu_to_je32(inode->i_ino);
	ri->mode = cpu_to_jemode(inode->i_mode);
	ri->uid = cpu_to_je16(inode->i_uid);
	ri->gid = cpu_to_je16(inode->i_gid);
	ri->isize = cpu_to_je32((uint32_t)inode->i_size);
	ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());

	/* In 2.4, it was already kmapped by generic_file_write(). Doesn't
	   hurt to do it again. The alternative is ifdefs, which are ugly. */
	kmap(pg);

	ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
				      (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
				      end - aligned_start, &writtenlen);

	kunmap(pg);

	if (ret) {
		/* There was an error writing. */
		SetPageError(pg);
	}

	/* Adjust writtenlen for the padding we did, so we don't confuse our caller */
	writtenlen -= min(writtenlen, (start - aligned_start));

	if (writtenlen) {
		if (inode->i_size < pos + writtenlen) {
			inode->i_size = pos + writtenlen;
			inode->i_blocks = (inode->i_size + 511) >> 9;

			inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
		}
	}

static ssize_t rtems_jffs2_file_write(rtems_libio_t *iop, const void *buf, size_t len)
{
	struct _inode *inode = rtems_jffs2_get_inode_by_iop(iop);
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	struct jffs2_raw_inode ri;
	uint32_t writtenlen;
	off_t pos;
	int eno = 0;

	memset(&ri, 0, sizeof(ri));

	ri.ino = cpu_to_je32(f->inocache->ino);
	ri.mode = cpu_to_jemode(inode->i_mode);
	ri.uid = cpu_to_je16(inode->i_uid);
	ri.gid = cpu_to_je16(inode->i_gid);
	ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());

	rtems_jffs2_do_lock(inode->i_sb);

	if ((iop->flags & LIBIO_FLAGS_APPEND) == 0) {
		pos = iop->offset;
	} else {
		pos = inode->i_size;
	}

	if (pos > inode->i_size) {
		ri.version = cpu_to_je32(++f->highest_version);
		eno = -jffs2_extend_file(inode, &ri, pos);
	}

	if (eno == 0) {
		ri.isize = cpu_to_je32(inode->i_size);

		eno = -jffs2_write_inode_range(c, f, &ri, (void *) buf, pos, len, &writtenlen);
	}

	if (eno == 0) {
		pos += writtenlen;

		inode->i_mtime = inode->i_ctime = je32_to_cpu(ri.mtime);

		if (pos > inode->i_size) {
			inode->i_size = pos;
		}

		iop->offset = pos;

		if (writtenlen != len) {
			eno = ENOSPC;
		}
	}

	rtems_jffs2_do_unlock(inode->i_sb);

	if (eno == 0) {
		return writtenlen;
	} else {
		errno = eno;

		return -1;
	}
}

static void jffs2_i_callback(struct rcu_head *head)
{
	struct inode *inode = container_of(head, struct inode, i_rcu);
	kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
}

static int jffs2_do_setattr (struct inode *inode, struct iattr *iattr)
{
	struct jffs2_full_dnode *old_metadata, *new_metadata;
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	struct jffs2_raw_inode *ri;
	unsigned short dev;
	unsigned char *mdata = NULL;
	int mdatalen = 0;
	unsigned int ivalid;
	uint32_t phys_ofs, alloclen;
	int ret;
	D1(printk(KERN_DEBUG "jffs2_setattr(): ino #%lu\n", inode->i_ino));
	ret = inode_change_ok(inode, iattr);
	if (ret) 
		return ret;

	/* Special cases - we don't want more than one data node
	   for these types on the medium at any time. So setattr
	   must read the original data associated with the node
	   (i.e. the device numbers or the target name) and write
	   it out again with the appropriate data attached */
	if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) {
		/* For these, we don't actually need to read the old node */
		dev = old_encode_dev(inode->i_rdev);
		mdata = (char *)&dev;
		mdatalen = sizeof(dev);
		D1(printk(KERN_DEBUG "jffs2_setattr(): Writing %d bytes of kdev_t\n", mdatalen));
	} else if (S_ISLNK(inode->i_mode)) {
		mdatalen = f->metadata->size;
		mdata = kmalloc(f->metadata->size, GFP_USER);
		if (!mdata)
			return -ENOMEM;
		ret = jffs2_read_dnode(c, f->metadata, mdata, 0, mdatalen);
		if (ret) {
			kfree(mdata);
			return ret;
		}
		D1(printk(KERN_DEBUG "jffs2_setattr(): Writing %d bytes of symlink target\n", mdatalen));
	}

	ri = jffs2_alloc_raw_inode();
	if (!ri) {
		if (S_ISLNK(inode->i_mode))
			kfree(mdata);
		return -ENOMEM;
	}
		
	ret = jffs2_reserve_space(c, sizeof(*ri) + mdatalen, &phys_ofs, &alloclen, ALLOC_NORMAL);
	if (ret) {
		jffs2_free_raw_inode(ri);
		if (S_ISLNK(inode->i_mode & S_IFMT))
			 kfree(mdata);
		return ret;
	}
	down(&f->sem);
	ivalid = iattr->ia_valid;
	
	ri->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
	ri->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
	ri->totlen = cpu_to_je32(sizeof(*ri) + mdatalen);
	ri->hdr_crc = cpu_to_je32(crc32(0, ri, sizeof(struct jffs2_unknown_node)-4));

	ri->ino = cpu_to_je32(inode->i_ino);
	ri->version = cpu_to_je32(++f->highest_version);

	ri->uid = cpu_to_je16((ivalid & ATTR_UID)?iattr->ia_uid:inode->i_uid);
	ri->gid = cpu_to_je16((ivalid & ATTR_GID)?iattr->ia_gid:inode->i_gid);

	if (ivalid & ATTR_MODE)
		if (iattr->ia_mode & S_ISGID &&
		    !in_group_p(je16_to_cpu(ri->gid)) && !capable(CAP_FSETID))
			ri->mode = cpu_to_jemode(iattr->ia_mode & ~S_ISGID);
		else 
			ri->mode = cpu_to_jemode(iattr->ia_mode);
	else
		ri->mode = cpu_to_jemode(inode->i_mode);


	ri->isize = cpu_to_je32((ivalid & ATTR_SIZE)?iattr->ia_size:inode->i_size);
	ri->atime = cpu_to_je32(I_SEC((ivalid & ATTR_ATIME)?iattr->ia_atime:inode->i_atime));
	ri->mtime = cpu_to_je32(I_SEC((ivalid & ATTR_MTIME)?iattr->ia_mtime:inode->i_mtime));
	ri->ctime = cpu_to_je32(I_SEC((ivalid & ATTR_CTIME)?iattr->ia_ctime:inode->i_ctime));

	ri->offset = cpu_to_je32(0);
	ri->csize = ri->dsize = cpu_to_je32(mdatalen);
	ri->compr = JFFS2_COMPR_NONE;
	if (ivalid & ATTR_SIZE && inode->i_size < iattr->ia_size) {
		/* It's an extension. Make it a hole node */
		ri->compr = JFFS2_COMPR_ZERO;
		ri->dsize = cpu_to_je32(iattr->ia_size - inode->i_size);
		ri->offset = cpu_to_je32(inode->i_size);
	}
	ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));
	if (mdatalen)
		ri->data_crc = cpu_to_je32(crc32(0, mdata, mdatalen));
	else
		ri->data_crc = cpu_to_je32(0);

	new_metadata = jffs2_write_dnode(c, f, ri, mdata, mdatalen, phys_ofs, ALLOC_NORMAL);
//.........这里部分代码省略.........

struct jffs2_inode_info *jffs2_gc_fetch_inode(struct jffs2_sb_info *c,
						     int inum, int nlink)
{
	struct inode *inode;
	struct jffs2_inode_cache *ic;
	if (!nlink) {
		/* The inode has zero nlink but its nodes weren't yet marked
		   obsolete. This has to be because we're still waiting for 
		   the final (close() and) iput() to happen.

		   There's a possibility that the final iput() could have 
		   happened while we were contemplating. In order to ensure
		   that we don't cause a new read_inode() (which would fail)
		   for the inode in question, we use ilookup() in this case
		   instead of iget().

		   The nlink can't _become_ zero at this point because we're 
		   holding the alloc_sem, and jffs2_do_unlink() would also
		   need that while decrementing nlink on any inode.
		*/
		inode = ilookup(OFNI_BS_2SFFJ(c), inum);
		if (!inode) {
			D1(printk(KERN_DEBUG "ilookup() failed for ino #%u; inode is probably deleted.\n",
				  inum));

			spin_lock(&c->inocache_lock);
			ic = jffs2_get_ino_cache(c, inum);
			if (!ic) {
				D1(printk(KERN_DEBUG "Inode cache for ino #%u is gone.\n", inum));
				spin_unlock(&c->inocache_lock);
				return NULL;
			}
			if (ic->state != INO_STATE_CHECKEDABSENT) {
				/* Wait for progress. Don't just loop */
				D1(printk(KERN_DEBUG "Waiting for ino #%u in state %d\n",
					  ic->ino, ic->state));
				sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
			} else {
				spin_unlock(&c->inocache_lock);
			}

			return NULL;
		}
	} else {
		/* Inode has links to it still; they're not going away because
		   jffs2_do_unlink() would need the alloc_sem and we have it.
		   Just iget() it, and if read_inode() is necessary that's OK.
		*/
		inode = iget(OFNI_BS_2SFFJ(c), inum);
		if (!inode)
			return ERR_PTR(-ENOMEM);
	}
	if (is_bad_inode(inode)) {
		printk(KERN_NOTICE "Eep. read_inode() failed for ino #%u. nlink %d\n",
		       inum, nlink);
		/* NB. This will happen again. We need to do something appropriate here. */
		iput(inode);
		return ERR_PTR(-EIO);
	}

	return JFFS2_INODE_INFO(inode);
}

int jffs2_do_setattr (struct inode *inode, struct iattr *iattr)
{
	struct jffs2_full_dnode *old_metadata, *new_metadata;
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	struct jffs2_raw_inode *ri;
	union jffs2_device_node dev;
	unsigned char *mdata = NULL;
	int mdatalen = 0;
	unsigned int ivalid;
	uint32_t alloclen;
	int ret;
	int alloc_type = ALLOC_NORMAL;

	D1(printk(KERN_DEBUG "jffs2_setattr(): ino #%lu\n", inode->i_ino));

	/* Special cases - we don't want more than one data node
	   for these types on the medium at any time. So setattr
	   must read the original data associated with the node
	   (i.e. the device numbers or the target name) and write
	   it out again with the appropriate data attached */
	if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) {
		/* For these, we don't actually need to read the old node */
		mdatalen = jffs2_encode_dev(&dev, inode->i_rdev);
		mdata = (char *)&dev;
		D1(printk(KERN_DEBUG "jffs2_setattr(): Writing %d bytes of kdev_t\n", mdatalen));
	} else if (S_ISLNK(inode->i_mode)) {
		mutex_lock(&f->sem);
		mdatalen = f->metadata->size;
		mdata = kmalloc(f->metadata->size, GFP_USER);
		if (!mdata) {
			mutex_unlock(&f->sem);
			return -ENOMEM;
		}
		ret = jffs2_read_dnode(c, f, f->metadata, mdata, 0, mdatalen);
		if (ret) {
			mutex_unlock(&f->sem);
			kfree(mdata);
			return ret;
		}
		mutex_unlock(&f->sem);
		D1(printk(KERN_DEBUG "jffs2_setattr(): Writing %d bytes of symlink target\n", mdatalen));
	}

	ri = jffs2_alloc_raw_inode();
	if (!ri) {
		if (S_ISLNK(inode->i_mode))
			kfree(mdata);
		return -ENOMEM;
	}

	ret = jffs2_reserve_space(c, sizeof(*ri) + mdatalen, &alloclen,
				  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
	if (ret) {
		jffs2_free_raw_inode(ri);
		if (S_ISLNK(inode->i_mode & S_IFMT))
			 kfree(mdata);
		return ret;
	}
	mutex_lock(&f->sem);
	ivalid = iattr->ia_valid;

	ri->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
	ri->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
	ri->totlen = cpu_to_je32(sizeof(*ri) + mdatalen);
	ri->hdr_crc = cpu_to_je32(crc32(0, ri, sizeof(struct jffs2_unknown_node)-4));

	ri->ino = cpu_to_je32(inode->i_ino);
	ri->version = cpu_to_je32(++f->highest_version);

	ri->uid = cpu_to_je16((ivalid & ATTR_UID)?iattr->ia_uid:inode->i_uid);
	ri->gid = cpu_to_je16((ivalid & ATTR_GID)?iattr->ia_gid:inode->i_gid);

	if (ivalid & ATTR_MODE)
		ri->mode = cpu_to_jemode(iattr->ia_mode);
	else
		ri->mode = cpu_to_jemode(inode->i_mode);


	ri->isize = cpu_to_je32((ivalid & ATTR_SIZE)?iattr->ia_size:inode->i_size);
	ri->atime = cpu_to_je32(I_SEC((ivalid & ATTR_ATIME)?iattr->ia_atime:inode->i_atime));
	ri->mtime = cpu_to_je32(I_SEC((ivalid & ATTR_MTIME)?iattr->ia_mtime:inode->i_mtime));
	ri->ctime = cpu_to_je32(I_SEC((ivalid & ATTR_CTIME)?iattr->ia_ctime:inode->i_ctime));

	ri->offset = cpu_to_je32(0);
	ri->csize = ri->dsize = cpu_to_je32(mdatalen);
	ri->compr = JFFS2_COMPR_NONE;
	if (ivalid & ATTR_SIZE && inode->i_size < iattr->ia_size) {
		/* It's an extension. Make it a hole node */
		ri->compr = JFFS2_COMPR_ZERO;
		ri->dsize = cpu_to_je32(iattr->ia_size - inode->i_size);
		ri->offset = cpu_to_je32(inode->i_size);
	} else if (ivalid & ATTR_SIZE && !iattr->ia_size) {
		/* For truncate-to-zero, treat it as deletion because
		   it'll always be obsoleting all previous nodes */
		alloc_type = ALLOC_DELETION;
	}
	ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));
	if (mdatalen)
		ri->data_crc = cpu_to_je32(crc32(0, mdata, mdatalen));
//.........这里部分代码省略.........

int jffs2_commit_write (struct file *filp, struct page *pg, unsigned start, unsigned end)
{
	/* Actually commit the write from the page cache page we're looking at.
	 * For now, we write the full page out each time. It sucks, but it's simple
	 */
	struct inode *inode = pg->mapping->host;
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	__u32 newsize = max_t(__u32, filp->f_dentry->d_inode->i_size, (pg->index << PAGE_CACHE_SHIFT) + end);
	__u32 file_ofs = (pg->index << PAGE_CACHE_SHIFT);
	__u32 writelen = min((__u32)PAGE_CACHE_SIZE, newsize - file_ofs);
	struct jffs2_raw_inode *ri;
	int ret = 0;
	ssize_t writtenlen = 0;

	D1(printk(KERN_DEBUG "jffs2_commit_write(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));

	if (!start && end == PAGE_CACHE_SIZE) {
		/* We need to avoid deadlock with page_cache_read() in
		   jffs2_garbage_collect_pass(). So we have to mark the
		   page up to date, to prevent page_cache_read() from 
		   trying to re-lock it. */
		SetPageUptodate(pg);
	}

	ri = jffs2_alloc_raw_inode();
	if (!ri)
		return -ENOMEM;

	while(writelen) {
		struct jffs2_full_dnode *fn;
		unsigned char *comprbuf = NULL;
		unsigned char comprtype = JFFS2_COMPR_NONE;
		__u32 phys_ofs, alloclen;
		__u32 datalen, cdatalen;

		D2(printk(KERN_DEBUG "jffs2_commit_write() loop: 0x%x to write to 0x%x\n", writelen, file_ofs));

		ret = jffs2_reserve_space(c, sizeof(*ri) + JFFS2_MIN_DATA_LEN, &phys_ofs, &alloclen, ALLOC_NORMAL);
		if (ret) {
			SetPageError(pg);
			D1(printk(KERN_DEBUG "jffs2_reserve_space returned %d\n", ret));
			break;
		}
		down(&f->sem);
		datalen = writelen;
		cdatalen = min(alloclen - sizeof(*ri), writelen);

		comprbuf = kmalloc(cdatalen, GFP_KERNEL);
		if (comprbuf) {
			comprtype = jffs2_compress(page_address(pg)+ (file_ofs & (PAGE_CACHE_SIZE-1)), comprbuf, &datalen, &cdatalen);
		}
		if (comprtype == JFFS2_COMPR_NONE) {
			/* Either compression failed, or the allocation of comprbuf failed */
			if (comprbuf)
				kfree(comprbuf);
			comprbuf = page_address(pg) + (file_ofs & (PAGE_CACHE_SIZE -1));
			datalen = cdatalen;
		}
		/* Now comprbuf points to the data to be written, be it compressed or not.
		   comprtype holds the compression type, and comprtype == JFFS2_COMPR_NONE means
		   that the comprbuf doesn't need to be kfree()d. 
		*/

		ri->magic = JFFS2_MAGIC_BITMASK;
		ri->nodetype = JFFS2_NODETYPE_INODE;
		ri->totlen = sizeof(*ri) + cdatalen;
		ri->hdr_crc = crc32(0, ri, sizeof(struct jffs2_unknown_node)-4);

		ri->ino = inode->i_ino;
		ri->version = ++f->highest_version;
		ri->mode = inode->i_mode;
		ri->uid = inode->i_uid;
		ri->gid = inode->i_gid;
		ri->isize = max((__u32)inode->i_size, file_ofs + datalen);
		ri->atime = ri->ctime = ri->mtime = CURRENT_TIME;
		ri->offset = file_ofs;
		ri->csize = cdatalen;
		ri->dsize = datalen;
		ri->compr = comprtype;
		ri->node_crc = crc32(0, ri, sizeof(*ri)-8);
		ri->data_crc = crc32(0, comprbuf, cdatalen);

		fn = jffs2_write_dnode(inode, ri, comprbuf, cdatalen, phys_ofs, NULL);

		jffs2_complete_reservation(c);

		if (comprtype != JFFS2_COMPR_NONE)
			kfree(comprbuf);

		if (IS_ERR(fn)) {
			ret = PTR_ERR(fn);
			up(&f->sem);
			SetPageError(pg);
			break;
		}
		ret = jffs2_add_full_dnode_to_inode(c, f, fn);
		if (f->metadata) {
			jffs2_mark_node_obsolete(c, f->metadata->raw);
			jffs2_free_full_dnode(f->metadata);
//.........这里部分代码省略.........

int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
{
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	struct jffs2_node_frag *frag = f->fraglist;
	__u32 offset = pg->index << PAGE_CACHE_SHIFT;
	__u32 end = offset + PAGE_CACHE_SIZE;
	unsigned char *pg_buf;
	int ret;

	D1(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%x\n", inode->i_ino, offset));

	if (!PageLocked(pg))
                PAGE_BUG(pg);

	while(frag && frag->ofs + frag->size  <= offset) {
		//		D1(printk(KERN_DEBUG "skipping frag %d-%d; before the region we care about\n", frag->ofs, frag->ofs + frag->size));
		frag = frag->next;
	}

	pg_buf = kmap(pg);

	/* 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_readpage: offset %d, end %d\n", offset, end));
		if (!frag || frag->ofs > offset) {
			__u32 holesize = end - offset;
			if (frag) {
				D1(printk(KERN_NOTICE "Eep. Hole in ino %ld fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", inode->i_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(pg_buf, 0, holesize);
			pg_buf += holesize;
			offset += holesize;
			continue;
		} else if (frag->ofs < offset && (offset & (PAGE_CACHE_SIZE-1)) != 0) {
			D1(printk(KERN_NOTICE "Eep. Overlap in ino #%ld fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n",
				  inode->i_ino, frag->ofs, offset));
			D1(jffs2_print_frag_list(f));
			memset(pg_buf, 0, end - offset);
			ClearPageUptodate(pg);
			SetPageError(pg);
			kunmap(pg);
			return -EIO;
		} else if (!frag->node) {
			__u32 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(pg_buf, 0, holeend - offset);
			pg_buf += holeend - offset;
			offset = holeend;
			frag = frag->next;
			continue;
		} else {
			__u32 readlen;
			__u32 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%x\n", frag->ofs+fragofs, 
				  fragofs+frag->ofs+readlen, frag->node->raw->flash_offset & ~3));
			ret = jffs2_read_dnode(c, frag->node, pg_buf, fragofs + frag->ofs - frag->node->ofs, readlen);
			D2(printk(KERN_DEBUG "node read done\n"));
			if (ret) {
				D1(printk(KERN_DEBUG"jffs2_readpage error %d\n",ret));
				memset(pg_buf, 0, readlen);
				ClearPageUptodate(pg);
				SetPageError(pg);
				kunmap(pg);
				return ret;
			}
		
			pg_buf += readlen;
			offset += readlen;
			frag = frag->next;
			D2(printk(KERN_DEBUG "node read was OK. Looping\n"));
		}
	}
	D2(printk(KERN_DEBUG "readpage finishing\n"));
	SetPageUptodate(pg);
	ClearPageError(pg);

	flush_dcache_page(pg);

	kunmap(pg);
	D1(printk(KERN_DEBUG "readpage finished\n"));
	return 0;
}

static int jffs2_do_setattr (struct _inode *inode, struct iattr *iattr)
{
	struct jffs2_full_dnode *old_metadata, *new_metadata;
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	struct jffs2_raw_inode *ri;
	unsigned char *mdata = NULL;
	int mdatalen = 0;
	unsigned int ivalid;
	uint32_t alloclen;
	int ret;
	int alloc_type = ALLOC_NORMAL;

	jffs2_dbg(1, "%s(): ino #%lu\n", __func__, inode->i_ino);

	/* Special cases - we don't want more than one data node
	   for these types on the medium at any time. So setattr
	   must read the original data associated with the node
	   (i.e. the device numbers or the target name) and write
	   it out again with the appropriate data attached */
	if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) {
		return -EIO;
	} else if (S_ISLNK(inode->i_mode)) {
		mutex_lock(&f->sem);
		mdatalen = f->metadata->size;
		mdata = kmalloc(f->metadata->size, GFP_USER);
		if (!mdata) {
			mutex_unlock(&f->sem);
			return -ENOMEM;
		}
		ret = jffs2_read_dnode(c, f, f->metadata, mdata, 0, mdatalen);
		if (ret) {
			mutex_unlock(&f->sem);
			kfree(mdata);
			return ret;
		}
		mutex_unlock(&f->sem);
		jffs2_dbg(1, "%s(): Writing %d bytes of symlink target\n",
			  __func__, mdatalen);
	}

	ri = jffs2_alloc_raw_inode();
	if (!ri) {
		if (S_ISLNK(inode->i_mode))
			kfree(mdata);
		return -ENOMEM;
	}

	ret = jffs2_reserve_space(c, sizeof(*ri) + mdatalen, &alloclen,
				  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
	if (ret) {
		jffs2_free_raw_inode(ri);
		if (S_ISLNK(inode->i_mode))
			 kfree(mdata);
		return ret;
	}
	mutex_lock(&f->sem);
	ivalid = iattr->ia_valid;

	ri->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
	ri->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
	ri->totlen = cpu_to_je32(sizeof(*ri) + mdatalen);
	ri->hdr_crc = cpu_to_je32(crc32(0, ri, sizeof(struct jffs2_unknown_node)-4));

	ri->ino = cpu_to_je32(inode->i_ino);
	ri->version = cpu_to_je32(++f->highest_version);

	ri->uid = cpu_to_je16((ivalid & ATTR_UID)?
		from_kuid(&init_user_ns, iattr->ia_uid):i_uid_read(inode));
	ri->gid = cpu_to_je16((ivalid & ATTR_GID)?
		from_kgid(&init_user_ns, iattr->ia_gid):i_gid_read(inode));

	if (ivalid & ATTR_MODE)
		ri->mode = cpu_to_jemode(iattr->ia_mode);
	else
		ri->mode = cpu_to_jemode(inode->i_mode);


	ri->isize = cpu_to_je32((ivalid & ATTR_SIZE)?iattr->ia_size:inode->i_size);
	ri->atime = cpu_to_je32(I_SEC((ivalid & ATTR_ATIME)?iattr->ia_atime:inode->i_atime));
	ri->mtime = cpu_to_je32(I_SEC((ivalid & ATTR_MTIME)?iattr->ia_mtime:inode->i_mtime));
	ri->ctime = cpu_to_je32(I_SEC((ivalid & ATTR_CTIME)?iattr->ia_ctime:inode->i_ctime));

	ri->offset = cpu_to_je32(0);
	ri->csize = ri->dsize = cpu_to_je32(mdatalen);
	ri->compr = JFFS2_COMPR_NONE;
	if (ivalid & ATTR_SIZE && inode->i_size < iattr->ia_size) {
		/* It's an extension. Make it a hole node */
		ri->compr = JFFS2_COMPR_ZERO;
		ri->dsize = cpu_to_je32(iattr->ia_size - inode->i_size);
		ri->offset = cpu_to_je32(inode->i_size);
	} else if (ivalid & ATTR_SIZE && !iattr->ia_size) {
		/* For truncate-to-zero, treat it as deletion because
		   it'll always be obsoleting all previous nodes */
		alloc_type = ALLOC_DELETION;
	}
	ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));
	if (mdatalen)
		ri->data_crc = cpu_to_je32(crc32(0, mdata, mdatalen));
	else
//.........这里部分代码省略.........

static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
			loff_t pos, unsigned len, unsigned flags,
			struct page **pagep, void **fsdata)
{
	struct page *pg;
	struct inode *inode = mapping->host;
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	struct jffs2_raw_inode ri;
	uint32_t alloc_len = 0;
	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
	uint32_t pageofs = index << PAGE_CACHE_SHIFT;
	int ret = 0;

	D1(printk(KERN_DEBUG "%s()\n", __func__));

	if (pageofs > inode->i_size) {
		ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
					  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
		if (ret)
			return ret;
	}

	mutex_lock(&f->sem);
	pg = grab_cache_page_write_begin(mapping, index, flags);
	if (!pg) {
		if (alloc_len)
			jffs2_complete_reservation(c);
		mutex_unlock(&f->sem);
		return -ENOMEM;
	}
	*pagep = pg;

	if (alloc_len) {
		/* Make new hole frag from old EOF to new page */
		struct jffs2_full_dnode *fn;

		D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
			  (unsigned int)inode->i_size, pageofs));

		memset(&ri, 0, sizeof(ri));

		ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
		ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
		ri.totlen = cpu_to_je32(sizeof(ri));
		ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));

		ri.ino = cpu_to_je32(f->inocache->ino);
		ri.version = cpu_to_je32(++f->highest_version);
		ri.mode = cpu_to_jemode(inode->i_mode);
		ri.uid = cpu_to_je16(inode->i_uid);
		ri.gid = cpu_to_je16(inode->i_gid);
		ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
		ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
		ri.offset = cpu_to_je32(inode->i_size);
		ri.dsize = cpu_to_je32(pageofs - inode->i_size);
		ri.csize = cpu_to_je32(0);
		ri.compr = JFFS2_COMPR_ZERO;
		ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
		ri.data_crc = cpu_to_je32(0);

		fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);

		if (IS_ERR(fn)) {
			ret = PTR_ERR(fn);
			jffs2_complete_reservation(c);
			goto out_page;
		}
		ret = jffs2_add_full_dnode_to_inode(c, f, fn);
		if (f->metadata) {
			jffs2_mark_node_obsolete(c, f->metadata->raw);
			jffs2_free_full_dnode(f->metadata);
			f->metadata = NULL;
		}
		if (ret) {
			D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", ret));
			jffs2_mark_node_obsolete(c, fn->raw);
			jffs2_free_full_dnode(fn);
			jffs2_complete_reservation(c);
			goto out_page;
		}
		jffs2_complete_reservation(c);
		inode->i_size = pageofs;
	}

	/*
	 * Read in the page if it wasn't already present. Cannot optimize away
	 * the whole page write case until jffs2_write_end can handle the
	 * case of a short-copy.
	 */
	if (!PageUptodate(pg)) {
		ret = jffs2_do_readpage_nolock(inode, pg);
		if (ret)
			goto out_page;
	}
	mutex_unlock(&f->sem);
	D1(printk(KERN_DEBUG "end write_begin(). pg->flags %lx\n", pg->flags));
	return ret;

out_page:
//.........这里部分代码省略.........

static rtems_filesystem_eval_path_generic_status rtems_jffs2_eval_token(
	rtems_filesystem_eval_path_context_t *ctx,
	void *arg,
	const char *token,
	size_t tokenlen
)
{
	rtems_filesystem_eval_path_generic_status status =
		RTEMS_FILESYSTEM_EVAL_PATH_GENERIC_DONE;
	rtems_filesystem_location_info_t *currentloc =
		rtems_filesystem_eval_path_get_currentloc(ctx);
	struct _inode *dir_i = rtems_jffs2_get_inode_by_location(currentloc);
	bool access_ok = rtems_filesystem_eval_path_check_access(
		ctx,
		RTEMS_FS_PERMS_EXEC,
		dir_i->i_mode,
		dir_i->i_uid,
		dir_i->i_gid
	);

	if (access_ok) {
		struct _inode *entry_i;

		if (rtems_filesystem_is_current_directory(token, tokenlen)) {
			entry_i = dir_i;
			++entry_i->i_count;
		} else if (rtems_filesystem_is_parent_directory(token, tokenlen)) {
			entry_i = dir_i->i_parent;
			++entry_i->i_count;
		} else {
			entry_i = jffs2_lookup(dir_i, token, (int) tokenlen);
		}

		if (IS_ERR(entry_i)) {
			rtems_filesystem_eval_path_error(ctx, PTR_ERR(entry_i));
		} else if (entry_i != NULL) {
			bool terminal = !rtems_filesystem_eval_path_has_path(ctx);
			int eval_flags = rtems_filesystem_eval_path_get_flags(ctx);
			bool follow_sym_link = (eval_flags & RTEMS_FS_FOLLOW_SYM_LINK) != 0;

			rtems_filesystem_eval_path_clear_token(ctx);

			if (S_ISLNK(entry_i->i_mode) && (follow_sym_link || !terminal)) {
				struct jffs2_inode_info *f = JFFS2_INODE_INFO(entry_i);
				const char *target = f->target;

				rtems_filesystem_eval_path_recursive(ctx, target, strlen(target));

				jffs2_iput(entry_i);
			} else {
				if (S_ISDIR(entry_i->i_mode) && entry_i->i_parent == NULL) {
					entry_i->i_parent = dir_i;
					++dir_i->i_count;
				}

				jffs2_iput(dir_i);
				rtems_jffs2_set_location(currentloc, entry_i);

				if (rtems_filesystem_eval_path_has_path(ctx)) {
					status = RTEMS_FILESYSTEM_EVAL_PATH_GENERIC_CONTINUE;
				}
			}
		} else {
			status = RTEMS_FILESYSTEM_EVAL_PATH_GENERIC_NO_ENTRY;
		}
	}

	return status;
}

static int jffs2_create(struct inode *dir_i, struct dentry *dentry, int mode,
			struct nameidata *nd)
{
	struct jffs2_raw_inode *ri;
	struct jffs2_inode_info *f, *dir_f;
	struct jffs2_sb_info *c;
	struct inode *inode;
	int ret;

	ri = jffs2_alloc_raw_inode();
	if (!ri)
		return -ENOMEM;

	c = JFFS2_SB_INFO(dir_i->i_sb);

	D1(printk(KERN_DEBUG "jffs2_create()\n"));

	inode = jffs2_new_inode(dir_i, mode, ri);

	if (IS_ERR(inode)) {
		D1(printk(KERN_DEBUG "jffs2_new_inode() failed\n"));
		jffs2_free_raw_inode(ri);
		return PTR_ERR(inode);
	}

	inode->i_op = &jffs2_file_inode_operations;
	inode->i_fop = &jffs2_file_operations;
	inode->i_mapping->a_ops = &jffs2_file_address_operations;
	inode->i_mapping->nrpages = 0;

	f = JFFS2_INODE_INFO(inode);
	dir_f = JFFS2_INODE_INFO(dir_i);

	/* jffs2_do_create() will want to lock it, _after_ reserving
	   space and taking c-alloc_sem. If we keep it locked here,
	   lockdep gets unhappy (although it's a false positive;
	   nothing else will be looking at this inode yet so there's
	   no chance of AB-BA deadlock involving its f->sem). */
	mutex_unlock(&f->sem);

	ret = jffs2_do_create(c, dir_f, f, ri,
			      dentry->d_name.name, dentry->d_name.len);
	if (ret)
		goto fail;

	dir_i->i_mtime = dir_i->i_ctime = ITIME(je32_to_cpu(ri->ctime));

	jffs2_free_raw_inode(ri);

	D1(printk(KERN_DEBUG "jffs2_create: Created ino #%lu with mode %o, nlink %d(%d). nrpages %ld\n",
		  inode->i_ino, inode->i_mode, inode->i_nlink,
		  f->inocache->pino_nlink, inode->i_mapping->nrpages));

	d_instantiate(dentry, inode);
	unlock_new_inode(inode);
	return 0;

 fail:
	iget_failed(inode);
	jffs2_free_raw_inode(ri);
	return ret;
}