xattr.c

linux 内核源代码

		   size_t buffer_size, int flags)
{
	int err = 0;
	struct file *fp;
	struct page *page;
	char *data;
	struct address_space *mapping;
	size_t file_pos = 0;
	size_t buffer_pos = 0;
	struct inode *xinode;
	struct iattr newattrs;
	__u32 xahash = 0;

	if (get_inode_sd_version(inode) == STAT_DATA_V1)
		return -EOPNOTSUPP;

	/* Empty xattrs are ok, they're just empty files, no hash */
	if (buffer && buffer_size)
		xahash = xattr_hash(buffer, buffer_size);

      open_file:
	fp = open_xa_file(inode, name, flags);
	if (IS_ERR(fp)) {
		err = PTR_ERR(fp);
		goto out;
	}

	xinode = fp->f_path.dentry->d_inode;
	REISERFS_I(inode)->i_flags |= i_has_xattr_dir;

	/* we need to copy it off.. */
	if (xinode->i_nlink > 1) {
		fput(fp);
		err = reiserfs_xattr_del(inode, name);
		if (err < 0)
			goto out;
		/* We just killed the old one, we're not replacing anymore */
		if (flags & XATTR_REPLACE)
			flags &= ~XATTR_REPLACE;
		goto open_file;
	}

	/* Resize it so we're ok to write there */
	newattrs.ia_size = buffer_size;
	newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
	mutex_lock_nested(&xinode->i_mutex, I_MUTEX_XATTR);
	err = notify_change(fp->f_path.dentry, &newattrs);
	if (err)
		goto out_filp;

	mapping = xinode->i_mapping;
	while (buffer_pos < buffer_size || buffer_pos == 0) {
		size_t chunk;
		size_t skip = 0;
		size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1));
		if (buffer_size - buffer_pos > PAGE_CACHE_SIZE)
			chunk = PAGE_CACHE_SIZE;
		else
			chunk = buffer_size - buffer_pos;

		page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT);
		if (IS_ERR(page)) {
			err = PTR_ERR(page);
			goto out_filp;
		}

		lock_page(page);
		data = page_address(page);

		if (file_pos == 0) {
			struct reiserfs_xattr_header *rxh;
			skip = file_pos = sizeof(struct reiserfs_xattr_header);
			if (chunk + skip > PAGE_CACHE_SIZE)
				chunk = PAGE_CACHE_SIZE - skip;
			rxh = (struct reiserfs_xattr_header *)data;
			rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC);
			rxh->h_hash = cpu_to_le32(xahash);
		}

		err = reiserfs_prepare_write(fp, page, page_offset,
					    page_offset + chunk + skip);
		if (!err) {
			if (buffer)
				memcpy(data + skip, buffer + buffer_pos, chunk);
			err =
			    reiserfs_commit_write(fp, page, page_offset,
						  page_offset + chunk +
						  skip);
		}
		unlock_page(page);
		reiserfs_put_page(page);
		buffer_pos += chunk;
		file_pos += chunk;
		skip = 0;
		if (err || buffer_size == 0 || !buffer)
			break;
	}

	/* We can't mark the inode dirty if it's not hashed. This is the case
	 * when we're inheriting the default ACL. If we dirty it, the inode
	 * gets marked dirty, but won't (ever) make it onto the dirty list until
	 * it's synced explicitly to clear I_DIRTY. This is bad. */
	if (!hlist_unhashed(&inode->i_hash)) {
		inode->i_ctime = CURRENT_TIME_SEC;
		mark_inode_dirty(inode);
	}

      out_filp:
	mutex_unlock(&xinode->i_mutex);
	fput(fp);

      out:
	return err;
}

/*
 * inode->i_mutex: down
 */
int
reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer,
		   size_t buffer_size)
{
	ssize_t err = 0;
	struct file *fp;
	size_t isize;
	size_t file_pos = 0;
	size_t buffer_pos = 0;
	struct page *page;
	struct inode *xinode;
	__u32 hash = 0;

	if (name == NULL)
		return -EINVAL;

	/* We can't have xattrs attached to v1 items since they don't have
	 * generation numbers */
	if (get_inode_sd_version(inode) == STAT_DATA_V1)
		return -EOPNOTSUPP;

	fp = open_xa_file(inode, name, FL_READONLY);
	if (IS_ERR(fp)) {
		err = PTR_ERR(fp);
		goto out;
	}

	xinode = fp->f_path.dentry->d_inode;
	isize = xinode->i_size;
	REISERFS_I(inode)->i_flags |= i_has_xattr_dir;

	/* Just return the size needed */
	if (buffer == NULL) {
		err = isize - sizeof(struct reiserfs_xattr_header);
		goto out_dput;
	}

	if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) {
		err = -ERANGE;
		goto out_dput;
	}

	while (file_pos < isize) {
		size_t chunk;
		char *data;
		size_t skip = 0;
		if (isize - file_pos > PAGE_CACHE_SIZE)
			chunk = PAGE_CACHE_SIZE;
		else
			chunk = isize - file_pos;

		page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT);
		if (IS_ERR(page)) {
			err = PTR_ERR(page);
			goto out_dput;
		}

		lock_page(page);
		data = page_address(page);
		if (file_pos == 0) {
			struct reiserfs_xattr_header *rxh =
			    (struct reiserfs_xattr_header *)data;
			skip = file_pos = sizeof(struct reiserfs_xattr_header);
			chunk -= skip;
			/* Magic doesn't match up.. */
			if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) {
				unlock_page(page);
				reiserfs_put_page(page);
				reiserfs_warning(inode->i_sb,
						 "Invalid magic for xattr (%s) "
						 "associated with %k", name,
						 INODE_PKEY(inode));
				err = -EIO;
				goto out_dput;
			}
			hash = le32_to_cpu(rxh->h_hash);
		}
		memcpy(buffer + buffer_pos, data + skip, chunk);
		unlock_page(page);
		reiserfs_put_page(page);
		file_pos += chunk;
		buffer_pos += chunk;
		skip = 0;
	}
	err = isize - sizeof(struct reiserfs_xattr_header);

	if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) !=
	    hash) {
		reiserfs_warning(inode->i_sb,
				 "Invalid hash for xattr (%s) associated "
				 "with %k", name, INODE_PKEY(inode));
		err = -EIO;
	}

      out_dput:
	fput(fp);

      out:
	return err;
}

static int
__reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen)
{
	struct dentry *dentry;
	struct inode *dir = xadir->d_inode;
	int err = 0;

	dentry = lookup_one_len(name, xadir, namelen);
	if (IS_ERR(dentry)) {
		err = PTR_ERR(dentry);
		goto out;
	} else if (!dentry->d_inode) {
		err = -ENODATA;
		goto out_file;
	}

	/* Skip directories.. */
	if (S_ISDIR(dentry->d_inode->i_mode))
		goto out_file;

	if (!is_reiserfs_priv_object(dentry->d_inode)) {
		reiserfs_warning(dir->i_sb, "OID %08x [%.*s/%.*s] doesn't have "
				 "priv flag set [parent is %sset].",
				 le32_to_cpu(INODE_PKEY(dentry->d_inode)->
					     k_objectid), xadir->d_name.len,
				 xadir->d_name.name, namelen, name,
				 is_reiserfs_priv_object(xadir->
							 d_inode) ? "" :
				 "not ");
		dput(dentry);
		return -EIO;
	}

	err = dir->i_op->unlink(dir, dentry);
	if (!err)
		d_delete(dentry);

      out_file:
	dput(dentry);

      out:
	return err;
}

int reiserfs_xattr_del(struct inode *inode, const char *name)
{
	struct dentry *dir;
	int err;

	dir = open_xa_dir(inode, FL_READONLY);
	if (IS_ERR(dir)) {
		err = PTR_ERR(dir);
		goto out;
	}

	err = __reiserfs_xattr_del(dir, name, strlen(name));
	dput(dir);

	if (!err) {
		inode->i_ctime = CURRENT_TIME_SEC;
		mark_inode_dirty(inode);
	}

      out:
	return err;
}

/* The following are side effects of other operations that aren't explicitly
 * modifying extended attributes. This includes operations such as permissions
 * or ownership changes, object deletions, etc. */

static int
reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen,
			      loff_t offset, u64 ino, unsigned int d_type)
{
	struct dentry *xadir = (struct dentry *)buf;

	return __reiserfs_xattr_del(xadir, name, namelen);

}

/* This is called w/ inode->i_mutex downed */
int reiserfs_delete_xattrs(struct inode *inode)
{
	struct file *fp;
	struct dentry *dir, *root;
	int err = 0;

	/* Skip out, an xattr has no xattrs associated with it */
	if (is_reiserfs_priv_object(inode) ||
	    get_inode_sd_version(inode) == STAT_DATA_V1 ||
	    !reiserfs_xattrs(inode->i_sb)) {
		return 0;
	}
	reiserfs_read_lock_xattrs(inode->i_sb);
	dir = open_xa_dir(inode, FL_READONLY);
	reiserfs_read_unlock_xattrs(inode->i_sb);
	if (IS_ERR(dir)) {
		err = PTR_ERR(dir);
		goto out;
	} else if (!dir->d_inode) {
		dput(dir);
		return 0;
	}

	fp = dentry_open(dir, NULL, O_RDWR);
	if (IS_ERR(fp)) {
		err = PTR_ERR(fp);
		/* dentry_open dputs the dentry if it fails */
		goto out;
	}

	lock_kernel();
	err = xattr_readdir(fp, reiserfs_delete_xattrs_filler, dir);
	if (err) {
		unlock_kernel();
		goto out_dir;
	}

	/* Leftovers besides . and .. -- that's not good. */
	if (dir->d_inode->i_nlink <= 2) {
		root = get_xa_root(inode->i_sb, XATTR_REPLACE);
		reiserfs_write_lock_xattrs(inode->i_sb);
		err = vfs_rmdir(root->d_inode, dir);
		reiserfs_write_unlock_xattrs(inode->i_sb);
		dput(root);
	} else {
		reiserfs_warning(inode->i_sb,
				 "Couldn't remove all entries in directory");
	}
	unlock_kernel();

      out_dir:
	fput(fp);

      out:
	if (!err)
		REISERFS_I(inode)->i_flags =
		    REISERFS_I(inode)->i_flags & ~i_has_xattr_dir;
	return err;
}

struct reiserfs_chown_buf {
	struct inode *inode;
	struct dentry *xadir;
	struct iattr *attrs;
};

/* XXX: If there is a better way to do this, I'd love to hear about it */
static int
reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen,
			     loff_t offset, u64 ino, unsigned int d_type)
{
	struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf;
	struct dentry *xafile, *xadir = chown_buf->xadir;
	struct iattr *attrs = chown_buf->attrs;
	int err = 0;

	xafile = lookup_one_len(name, xadir, namelen);
	if (IS_ERR(xafile))
		return PTR_ERR(xafile);
	else if (!xafile->d_inode) {
		dput(xafile);
		return -ENODATA;
	}

	if (!S_ISDIR(xafile->d_inode->i_mode))
		err = notify_change(xafile, attrs);
	dput(xafile);

	return err;
}

int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
{
	struct file *fp;
	struct dentry *dir;
	int err = 0;
	struct reiserfs_chown_buf buf;
	unsigned int ia_valid = attrs->ia_valid;

	/* Skip out, an xattr has no xattrs associated with it */
	if (is_reiserfs_priv_object(inode) ||
	    get_inode_sd_version(inode) == STAT_DATA_V1 ||
	    !reiserfs_xattrs(inode->i_sb)) {
		return 0;
	}
	reiserfs_read_lock_xattrs(inode->i_sb);
	dir = open_xa_dir(inode, FL_READONLY);
	reiserfs_read_unlock_xattrs(inode->i_sb);
	if (IS_ERR(dir)) {
		if (PTR_ERR(dir) != -ENODATA)
			err = PTR_ERR(dir);
		goto out;
	} else if (!dir->d_inode) {
		dput(dir);
		goto out;
	}

	fp = dentry_open(dir, NULL, O_RDWR);
	if (IS_ERR(fp)) {
		err = PTR_ERR(fp);
		/* dentry_open dputs the dentry if it fails */
		goto out;
	}

	lock_kernel();

	attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME);
	buf.xadir = dir;
	buf.attrs = attrs;
	buf.inode = inode;

	err = xattr_readdir(fp, reiserfs_chown_xattrs_filler, &buf);
	if (err) {
		unlock_kernel();
		goto out_dir;
	}

	err = notify_change(dir, attrs);
	unlock_kernel();