vfs_inode.c

linux 内核源代码

		inode = NULL;
		goto error;
	}

	result = v9fs_fid_add(dentry, fid);
	if (result < 0)
		goto error;

	if ((fid->qid.version) && (v9ses->cache))
		dentry->d_op = &v9fs_cached_dentry_operations;
	else
		dentry->d_op = &v9fs_dentry_operations;

	d_add(dentry, inode);
	return NULL;

error:
	if (fid)
		p9_client_clunk(fid);

	return ERR_PTR(result);
}

/**
 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 * @i:  inode that is being unlinked
 * @d: dentry that is being unlinked
 *
 */

static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
{
	return v9fs_remove(i, d, 0);
}

/**
 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 * @i:  inode that is being unlinked
 * @d: dentry that is being unlinked
 *
 */

static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
{
	return v9fs_remove(i, d, 1);
}

/**
 * v9fs_vfs_rename - VFS hook to rename an inode
 * @old_dir:  old dir inode
 * @old_dentry: old dentry
 * @new_dir: new dir inode
 * @new_dentry: new dentry
 *
 */

static int
v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
		struct inode *new_dir, struct dentry *new_dentry)
{
	struct inode *old_inode;
	struct v9fs_session_info *v9ses;
	struct p9_fid *oldfid;
	struct p9_fid *olddirfid;
	struct p9_fid *newdirfid;
	struct p9_wstat wstat;
	int retval;

	P9_DPRINTK(P9_DEBUG_VFS, "\n");
	retval = 0;
	old_inode = old_dentry->d_inode;
	v9ses = v9fs_inode2v9ses(old_inode);
	oldfid = v9fs_fid_lookup(old_dentry);
	if (IS_ERR(oldfid))
		return PTR_ERR(oldfid);

	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
	if (IS_ERR(olddirfid)) {
		retval = PTR_ERR(olddirfid);
		goto done;
	}

	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
	if (IS_ERR(newdirfid)) {
		retval = PTR_ERR(newdirfid);
		goto clunk_olddir;
	}

	/* 9P can only handle file rename in the same directory */
	if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
		P9_DPRINTK(P9_DEBUG_ERROR,
				"old dir and new dir are different\n");
		retval = -EXDEV;
		goto clunk_newdir;
	}

	v9fs_blank_wstat(&wstat);
	wstat.muid = v9ses->uname;
	wstat.name = (char *) new_dentry->d_name.name;
	retval = p9_client_wstat(oldfid, &wstat);

clunk_newdir:
	p9_client_clunk(newdirfid);

clunk_olddir:
	p9_client_clunk(olddirfid);

done:
	return retval;
}

/**
 * v9fs_vfs_getattr - retrieve file metadata
 * @mnt - mount information
 * @dentry - file to get attributes on
 * @stat - metadata structure to populate
 *
 */

static int
v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
		 struct kstat *stat)
{
	int err;
	struct v9fs_session_info *v9ses;
	struct p9_fid *fid;
	struct p9_stat *st;

	P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
	err = -EPERM;
	v9ses = v9fs_inode2v9ses(dentry->d_inode);
	if (v9ses->cache == CACHE_LOOSE)
		return simple_getattr(mnt, dentry, stat);

	fid = v9fs_fid_lookup(dentry);
	if (IS_ERR(fid))
		return PTR_ERR(fid);

	st = p9_client_stat(fid);
	if (IS_ERR(st))
		return PTR_ERR(st);

	v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
		generic_fillattr(dentry->d_inode, stat);

	kfree(st);
	return 0;
}

/**
 * v9fs_vfs_setattr - set file metadata
 * @dentry: file whose metadata to set
 * @iattr: metadata assignment structure
 *
 */

static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
{
	int retval;
	struct v9fs_session_info *v9ses;
	struct p9_fid *fid;
	struct p9_wstat wstat;

	P9_DPRINTK(P9_DEBUG_VFS, "\n");
	retval = -EPERM;
	v9ses = v9fs_inode2v9ses(dentry->d_inode);
	fid = v9fs_fid_lookup(dentry);
	if(IS_ERR(fid))
		return PTR_ERR(fid);

	v9fs_blank_wstat(&wstat);
	if (iattr->ia_valid & ATTR_MODE)
		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);

	if (iattr->ia_valid & ATTR_MTIME)
		wstat.mtime = iattr->ia_mtime.tv_sec;

	if (iattr->ia_valid & ATTR_ATIME)
		wstat.atime = iattr->ia_atime.tv_sec;

	if (iattr->ia_valid & ATTR_SIZE)
		wstat.length = iattr->ia_size;

	if (v9fs_extended(v9ses)) {
		if (iattr->ia_valid & ATTR_UID)
			wstat.n_uid = iattr->ia_uid;

		if (iattr->ia_valid & ATTR_GID)
			wstat.n_gid = iattr->ia_gid;
	}

	retval = p9_client_wstat(fid, &wstat);
	if (retval >= 0)
		retval = inode_setattr(dentry->d_inode, iattr);

	return retval;
}

/**
 * v9fs_stat2inode - populate an inode structure with mistat info
 * @stat: Plan 9 metadata (mistat) structure
 * @inode: inode to populate
 * @sb: superblock of filesystem
 *
 */

void
v9fs_stat2inode(struct p9_stat *stat, struct inode *inode,
	struct super_block *sb)
{
	int n;
	char ext[32];
	struct v9fs_session_info *v9ses = sb->s_fs_info;

	inode->i_nlink = 1;

	inode->i_atime.tv_sec = stat->atime;
	inode->i_mtime.tv_sec = stat->mtime;
	inode->i_ctime.tv_sec = stat->mtime;

	inode->i_uid = v9ses->dfltuid;
	inode->i_gid = v9ses->dfltgid;

	if (v9fs_extended(v9ses)) {
		inode->i_uid = stat->n_uid;
		inode->i_gid = stat->n_gid;
	}

	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
		char type = 0;
		int major = -1;
		int minor = -1;

		n = stat->extension.len;
		if (n > sizeof(ext)-1)
			n = sizeof(ext)-1;
		memmove(ext, stat->extension.str, n);
		ext[n] = 0;
		sscanf(ext, "%c %u %u", &type, &major, &minor);
		switch (type) {
		case 'c':
			inode->i_mode &= ~S_IFBLK;
			inode->i_mode |= S_IFCHR;
			break;
		case 'b':
			break;
		default:
			P9_DPRINTK(P9_DEBUG_ERROR,
				"Unknown special type %c (%.*s)\n", type,
				stat->extension.len, stat->extension.str);
		};
		inode->i_rdev = MKDEV(major, minor);
	} else
		inode->i_rdev = 0;

	inode->i_size = stat->length;

	/* not real number of blocks, but 512 byte ones ... */
	inode->i_blocks = (inode->i_size + 512 - 1) >> 9;
}

/**
 * v9fs_qid2ino - convert qid into inode number
 * @qid: qid to hash
 *
 * BUG: potential for inode number collisions?
 */

ino_t v9fs_qid2ino(struct p9_qid *qid)
{
	u64 path = qid->path + 2;
	ino_t i = 0;

	if (sizeof(ino_t) == sizeof(path))
		memcpy(&i, &path, sizeof(ino_t));
	else
		i = (ino_t) (path ^ (path >> 32));

	return i;
}

/**
 * v9fs_readlink - read a symlink's location (internal version)
 * @dentry: dentry for symlink
 * @buffer: buffer to load symlink location into
 * @buflen: length of buffer
 *
 */

static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
{
	int retval;

	struct v9fs_session_info *v9ses;
	struct p9_fid *fid;
	struct p9_stat *st;

	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
	retval = -EPERM;
	v9ses = v9fs_inode2v9ses(dentry->d_inode);
	fid = v9fs_fid_lookup(dentry);
	if (IS_ERR(fid))
		return PTR_ERR(fid);

	if (!v9fs_extended(v9ses))
		return -EBADF;

	st = p9_client_stat(fid);
	if (IS_ERR(st))
		return PTR_ERR(st);

	if (!(st->mode & P9_DMSYMLINK)) {
		retval = -EINVAL;
		goto done;
	}

	/* copy extension buffer into buffer */
	if (st->extension.len < buflen)
		buflen = st->extension.len + 1;

	memmove(buffer, st->extension.str, buflen - 1);
	buffer[buflen-1] = 0;

	P9_DPRINTK(P9_DEBUG_VFS,
		"%s -> %.*s (%s)\n", dentry->d_name.name, st->extension.len,
		st->extension.str, buffer);

	retval = buflen;

done:
	kfree(st);
	return retval;
}

/**
 * v9fs_vfs_readlink - read a symlink's location
 * @dentry: dentry for symlink
 * @buf: buffer to load symlink location into
 * @buflen: length of buffer
 *
 */

static int v9fs_vfs_readlink(struct dentry *dentry, char __user * buffer,
			     int buflen)
{
	int retval;
	int ret;
	char *link = __getname();

	if (unlikely(!link))
		return -ENOMEM;

	if (buflen > PATH_MAX)
		buflen = PATH_MAX;

	P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);

	retval = v9fs_readlink(dentry, link, buflen);

	if (retval > 0) {
		if ((ret = copy_to_user(buffer, link, retval)) != 0) {
			P9_DPRINTK(P9_DEBUG_ERROR,
					"problem copying to user: %d\n", ret);
			retval = ret;
		}
	}

	__putname(link);
	return retval;
}

/**
 * v9fs_vfs_follow_link - follow a symlink path
 * @dentry: dentry for symlink
 * @nd: nameidata
 *
 */

static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
	int len = 0;
	char *link = __getname();

	P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);

	if (!link)
		link = ERR_PTR(-ENOMEM);
	else {
		len = v9fs_readlink(dentry, link, PATH_MAX);

		if (len < 0) {
			__putname(link);
			link = ERR_PTR(len);
		} else
			link[len] = 0;
	}
	nd_set_link(nd, link);

	return NULL;
}

/**
 * v9fs_vfs_put_link - release a symlink path
 * @dentry: dentry for symlink
 * @nd: nameidata
 *
 */

static void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
{
	char *s = nd_get_link(nd);

	P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name, s);
	if (!IS_ERR(s))
		__putname(s);
}

static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
	int mode, const char *extension)
{
	u32 perm;
	struct v9fs_session_info *v9ses;
	struct p9_fid *fid;

	v9ses = v9fs_inode2v9ses(dir);
	if (!v9fs_extended(v9ses)) {
		P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
		return -EPERM;
	}

	perm = unixmode2p9mode(v9ses, mode);
	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
								P9_OREAD);
	if (IS_ERR(fid))
		return PTR_ERR(fid);

	p9_client_clunk(fid);
	return 0;
}

/**
 * v9fs_vfs_symlink - helper function to create symlinks
 * @dir: directory inode containing symlink
 * @dentry: dentry for symlink
 * @symname: symlink data
 *
 * See 9P2000.u RFC for more information
 *
 */

static int
v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
{
	P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
					dentry->d_name.name, symname);

	return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
}

/**
 * v9fs_vfs_link - create a hardlink
 * @old_dentry: dentry for file to link to
 * @dir: inode destination for new link
 * @dentry: dentry for link
 *
 */

/* XXX - lots of code dup'd from symlink and creates,
 * figure out a better reuse strategy
 */

static int
v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
	      struct dentry *dentry)
{
	int retval;
	struct p9_fid *oldfid;
	char *name;

	P9_DPRINTK(P9_DEBUG_VFS,
		" %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
		old_dentry->d_name.name);

	oldfid = v9fs_fid_clone(old_dentry);
	if (IS_ERR(oldfid))
		return PTR_ERR(oldfid);

	name = __getname();
	if (unlikely(!name)) {
		retval = -ENOMEM;
		goto clunk_fid;
	}

	sprintf(name, "%d\n", oldfid->fid);
	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
	__putname(name);

clunk_fid:
	p9_client_clunk(oldfid);
	return retval;
}

/**
 * v9fs_vfs_mknod - create a special file
 * @dir: inode destination for new link
 * @dentry: dentry for file
 * @mode: mode for creation
 * @dev_t: device associated with special file
 *
 */

static int
v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
{
	int retval;
	char *name;

	P9_DPRINTK(P9_DEBUG_VFS,
		" %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
		dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));

	if (!new_valid_dev(rdev))
		return -EINVAL;

	name = __getname();
	if (!name)
		return -ENOMEM;
	/* build extension */
	if (S_ISBLK(mode))
		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
	else if (S_ISCHR(mode))
		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
	else if (S_ISFIFO(mode))
		*name = 0;
	else {
		__putname(name);
		return -EINVAL;
	}

	retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
	__putname(name);

	return retval;
}

static const struct inode_operations v9fs_dir_inode_operations_ext = {
	.create = v9fs_vfs_create,
	.lookup = v9fs_vfs_lookup,
	.symlink = v9fs_vfs_symlink,
	.link = v9fs_vfs_link,
	.unlink = v9fs_vfs_unlink,
	.mkdir = v9fs_vfs_mkdir,
	.rmdir = v9fs_vfs_rmdir,
	.mknod = v9fs_vfs_mknod,
	.rename = v9fs_vfs_rename,
	.readlink = v9fs_vfs_readlink,
	.getattr = v9fs_vfs_getattr,
	.setattr = v9fs_vfs_setattr,
};

static const struct inode_operations v9fs_dir_inode_operations = {
	.create = v9fs_vfs_create,
	.lookup = v9fs_vfs_lookup,
	.unlink = v9fs_vfs_unlink,
	.mkdir = v9fs_vfs_mkdir,
	.rmdir = v9fs_vfs_rmdir,
	.mknod = v9fs_vfs_mknod,
	.rename = v9fs_vfs_rename,
	.getattr = v9fs_vfs_getattr,
	.setattr = v9fs_vfs_setattr,
};

static const struct inode_operations v9fs_file_inode_operations = {
	.getattr = v9fs_vfs_getattr,
	.setattr = v9fs_vfs_setattr,
};

static const struct inode_operations v9fs_symlink_inode_operations = {
	.readlink = v9fs_vfs_readlink,
	.follow_link = v9fs_vfs_follow_link,
	.put_link = v9fs_vfs_put_link,
	.getattr = v9fs_vfs_getattr,
	.setattr = v9fs_vfs_setattr,
};