ops_inode.c

linux 内核源代码

		if (ip == nip)
			return 0;
	}

	/* Make sure we aren't trying to move a dirctory into it's subdir */

	if (S_ISDIR(ip->i_inode.i_mode) && odip != ndip) {
		dir_rename = 1;

		error = gfs2_glock_nq_init(sdp->sd_rename_gl, LM_ST_EXCLUSIVE, 0,
					   &r_gh);
		if (error)
			goto out;

		error = gfs2_ok_to_move(ip, ndip);
		if (error)
			goto out_gunlock_r;
	}

	num_gh = 1;
	gfs2_holder_init(odip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
	if (odip != ndip) {
		gfs2_holder_init(ndip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
		num_gh++;
	}
	gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
	num_gh++;

	if (nip) {
		gfs2_holder_init(nip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
		num_gh++;
		/* grab the resource lock for unlink flag twiddling 
		 * this is the case of the target file already existing
		 * so we unlink before doing the rename
		 */
		nrgd = gfs2_blk2rgrpd(sdp, nip->i_no_addr);
		if (nrgd)
			gfs2_holder_init(nrgd->rd_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh++);
	}

	error = gfs2_glock_nq_m(num_gh, ghs);
	if (error)
		goto out_uninit;

	/* Check out the old directory */

	error = gfs2_unlink_ok(odip, &odentry->d_name, ip);
	if (error)
		goto out_gunlock;

	/* Check out the new directory */

	if (nip) {
		error = gfs2_unlink_ok(ndip, &ndentry->d_name, nip);
		if (error)
			goto out_gunlock;

		if (S_ISDIR(nip->i_inode.i_mode)) {
			if (nip->i_di.di_entries < 2) {
				if (gfs2_consist_inode(nip))
					gfs2_dinode_print(nip);
				error = -EIO;
				goto out_gunlock;
			}
			if (nip->i_di.di_entries > 2) {
				error = -ENOTEMPTY;
				goto out_gunlock;
			}
		}
	} else {
		error = permission(ndir, MAY_WRITE | MAY_EXEC, NULL);
		if (error)
			goto out_gunlock;

		error = gfs2_dir_check(ndir, &ndentry->d_name, NULL);
		switch (error) {
		case -ENOENT:
			error = 0;
			break;
		case 0:
			error = -EEXIST;
		default:
			goto out_gunlock;
		};

		if (odip != ndip) {
			if (!ndip->i_inode.i_nlink) {
				error = -EINVAL;
				goto out_gunlock;
			}
			if (ndip->i_di.di_entries == (u32)-1) {
				error = -EFBIG;
				goto out_gunlock;
			}
			if (S_ISDIR(ip->i_inode.i_mode) &&
			    ndip->i_inode.i_nlink == (u32)-1) {
				error = -EMLINK;
				goto out_gunlock;
			}
		}
	}

	/* Check out the dir to be renamed */

	if (dir_rename) {
		error = permission(odentry->d_inode, MAY_WRITE, NULL);
		if (error)
			goto out_gunlock;
	}

	alloc_required = error = gfs2_diradd_alloc_required(ndir, &ndentry->d_name);
	if (error < 0)
		goto out_gunlock;
	error = 0;

	if (alloc_required) {
		struct gfs2_alloc *al = gfs2_alloc_get(ndip);

		error = gfs2_quota_lock(ndip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
		if (error)
			goto out_alloc;

		error = gfs2_quota_check(ndip, ndip->i_inode.i_uid, ndip->i_inode.i_gid);
		if (error)
			goto out_gunlock_q;

		al->al_requested = sdp->sd_max_dirres;

		error = gfs2_inplace_reserve(ndip);
		if (error)
			goto out_gunlock_q;

		error = gfs2_trans_begin(sdp, sdp->sd_max_dirres +
					 al->al_rgd->rd_length +
					 4 * RES_DINODE + 4 * RES_LEAF +
					 RES_STATFS + RES_QUOTA + 4, 0);
		if (error)
			goto out_ipreserv;
	} else {
		error = gfs2_trans_begin(sdp, 4 * RES_DINODE +
					 5 * RES_LEAF + 4, 0);
		if (error)
			goto out_gunlock;
	}

	/* Remove the target file, if it exists */

	if (nip) {
		if (S_ISDIR(nip->i_inode.i_mode))
			error = gfs2_rmdiri(ndip, &ndentry->d_name, nip);
		else {
			error = gfs2_dir_del(ndip, &ndentry->d_name);
			if (error)
				goto out_end_trans;
			error = gfs2_change_nlink(nip, -1);
		}
		if (error)
			goto out_end_trans;
	}

	if (dir_rename) {
		struct qstr name;
		gfs2_str2qstr(&name, "..");

		error = gfs2_change_nlink(ndip, +1);
		if (error)
			goto out_end_trans;
		error = gfs2_change_nlink(odip, -1);
		if (error)
			goto out_end_trans;

		error = gfs2_dir_mvino(ip, &name, ndip, DT_DIR);
		if (error)
			goto out_end_trans;
	} else {
		struct buffer_head *dibh;
		error = gfs2_meta_inode_buffer(ip, &dibh);
		if (error)
			goto out_end_trans;
		ip->i_inode.i_ctime = CURRENT_TIME;
		gfs2_trans_add_bh(ip->i_gl, dibh, 1);
		gfs2_dinode_out(ip, dibh->b_data);
		brelse(dibh);
	}

	error = gfs2_dir_del(odip, &odentry->d_name);
	if (error)
		goto out_end_trans;

	error = gfs2_dir_add(ndir, &ndentry->d_name, ip, IF2DT(ip->i_inode.i_mode));
	if (error)
		goto out_end_trans;

out_end_trans:
	gfs2_trans_end(sdp);
out_ipreserv:
	if (alloc_required)
		gfs2_inplace_release(ndip);
out_gunlock_q:
	if (alloc_required)
		gfs2_quota_unlock(ndip);
out_alloc:
	if (alloc_required)
		gfs2_alloc_put(ndip);
out_gunlock:
	gfs2_glock_dq_m(num_gh, ghs);
out_uninit:
	for (x = 0; x < num_gh; x++)
		gfs2_holder_uninit(ghs + x);
out_gunlock_r:
	if (dir_rename)
		gfs2_glock_dq_uninit(&r_gh);
out:
	return error;
}

/**
 * gfs2_readlink - Read the value of a symlink
 * @dentry: the symlink
 * @buf: the buffer to read the symlink data into
 * @size: the size of the buffer
 *
 * Returns: errno
 */

static int gfs2_readlink(struct dentry *dentry, char __user *user_buf,
			 int user_size)
{
	struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
	char array[GFS2_FAST_NAME_SIZE], *buf = array;
	unsigned int len = GFS2_FAST_NAME_SIZE;
	int error;

	error = gfs2_readlinki(ip, &buf, &len);
	if (error)
		return error;

	if (user_size > len - 1)
		user_size = len - 1;

	if (copy_to_user(user_buf, buf, user_size))
		error = -EFAULT;
	else
		error = user_size;

	if (buf != array)
		kfree(buf);

	return error;
}

/**
 * gfs2_follow_link - Follow a symbolic link
 * @dentry: The dentry of the link
 * @nd: Data that we pass to vfs_follow_link()
 *
 * This can handle symlinks of any size. It is optimised for symlinks
 * under GFS2_FAST_NAME_SIZE.
 *
 * Returns: 0 on success or error code
 */

static void *gfs2_follow_link(struct dentry *dentry, struct nameidata *nd)
{
	struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
	char array[GFS2_FAST_NAME_SIZE], *buf = array;
	unsigned int len = GFS2_FAST_NAME_SIZE;
	int error;

	error = gfs2_readlinki(ip, &buf, &len);
	if (!error) {
		error = vfs_follow_link(nd, buf);
		if (buf != array)
			kfree(buf);
	}

	return ERR_PTR(error);
}

/**
 * gfs2_permission -
 * @inode:
 * @mask:
 * @nd: passed from Linux VFS, ignored by us
 *
 * This may be called from the VFS directly, or from within GFS2 with the
 * inode locked, so we look to see if the glock is already locked and only
 * lock the glock if its not already been done.
 *
 * Returns: errno
 */

static int gfs2_permission(struct inode *inode, int mask, struct nameidata *nd)
{
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_holder i_gh;
	int error;
	int unlock = 0;

	if (gfs2_glock_is_locked_by_me(ip->i_gl) == 0) {
		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
		if (error)
			return error;
		unlock = 1;
	}

	error = generic_permission(inode, mask, gfs2_check_acl);
	if (unlock)
		gfs2_glock_dq_uninit(&i_gh);

	return error;
}

static int setattr_size(struct inode *inode, struct iattr *attr)
{
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_sbd *sdp = GFS2_SB(inode);
	int error;

	if (attr->ia_size != ip->i_di.di_size) {
		error = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);
		if (error)
			return error;
		error = vmtruncate(inode, attr->ia_size);
		gfs2_trans_end(sdp);
		if (error) 
			return error;
	}

	error = gfs2_truncatei(ip, attr->ia_size);
	if (error && (inode->i_size != ip->i_di.di_size))
		i_size_write(inode, ip->i_di.di_size);

	return error;
}

static int setattr_chown(struct inode *inode, struct iattr *attr)
{
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_sbd *sdp = GFS2_SB(inode);
	struct buffer_head *dibh;
	u32 ouid, ogid, nuid, ngid;
	int error;

	ouid = inode->i_uid;
	ogid = inode->i_gid;
	nuid = attr->ia_uid;
	ngid = attr->ia_gid;

	if (!(attr->ia_valid & ATTR_UID) || ouid == nuid)
		ouid = nuid = NO_QUOTA_CHANGE;
	if (!(attr->ia_valid & ATTR_GID) || ogid == ngid)
		ogid = ngid = NO_QUOTA_CHANGE;

	gfs2_alloc_get(ip);

	error = gfs2_quota_lock(ip, nuid, ngid);
	if (error)
		goto out_alloc;

	if (ouid != NO_QUOTA_CHANGE || ogid != NO_QUOTA_CHANGE) {
		error = gfs2_quota_check(ip, nuid, ngid);
		if (error)
			goto out_gunlock_q;
	}

	error = gfs2_trans_begin(sdp, RES_DINODE + 2 * RES_QUOTA, 0);
	if (error)
		goto out_gunlock_q;

	error = gfs2_meta_inode_buffer(ip, &dibh);
	if (error)
		goto out_end_trans;

	error = inode_setattr(inode, attr);
	gfs2_assert_warn(sdp, !error);

	gfs2_trans_add_bh(ip->i_gl, dibh, 1);
	gfs2_dinode_out(ip, dibh->b_data);
	brelse(dibh);

	if (ouid != NO_QUOTA_CHANGE || ogid != NO_QUOTA_CHANGE) {
		gfs2_quota_change(ip, -ip->i_di.di_blocks, ouid, ogid);
		gfs2_quota_change(ip, ip->i_di.di_blocks, nuid, ngid);
	}

out_end_trans:
	gfs2_trans_end(sdp);
out_gunlock_q:
	gfs2_quota_unlock(ip);
out_alloc:
	gfs2_alloc_put(ip);
	return error;
}

/**
 * gfs2_setattr - Change attributes on an inode
 * @dentry: The dentry which is changing
 * @attr: The structure describing the change
 *
 * The VFS layer wants to change one or more of an inodes attributes.  Write
 * that change out to disk.
 *
 * Returns: errno
 */

static int gfs2_setattr(struct dentry *dentry, struct iattr *attr)
{
	struct inode *inode = dentry->d_inode;
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_holder i_gh;
	int error;

	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
	if (error)
		return error;

	error = -EPERM;
	if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
		goto out;

	error = inode_change_ok(inode, attr);
	if (error)
		goto out;

	if (attr->ia_valid & ATTR_SIZE)
		error = setattr_size(inode, attr);
	else if (attr->ia_valid & (ATTR_UID | ATTR_GID))
		error = setattr_chown(inode, attr);
	else if ((attr->ia_valid & ATTR_MODE) && IS_POSIXACL(inode))
		error = gfs2_acl_chmod(ip, attr);
	else
		error = gfs2_setattr_simple(ip, attr);

out:
	gfs2_glock_dq_uninit(&i_gh);
	if (!error)
		mark_inode_dirty(inode);
	return error;
}

/**
 * gfs2_getattr - Read out an inode's attributes
 * @mnt: The vfsmount the inode is being accessed from
 * @dentry: The dentry to stat
 * @stat: The inode's stats
 *
 * This may be called from the VFS directly, or from within GFS2 with the
 * inode locked, so we look to see if the glock is already locked and only
 * lock the glock if its not already been done. Note that its the NFS
 * readdirplus operation which causes this to be called (from filldir)
 * with the glock already held.
 *
 * Returns: errno
 */

static int gfs2_getattr(struct vfsmount *mnt, struct dentry *dentry,
			struct kstat *stat)
{
	struct inode *inode = dentry->d_inode;
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_holder gh;
	int error;
	int unlock = 0;

	if (gfs2_glock_is_locked_by_me(ip->i_gl) == 0) {
		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &gh);
		if (error)
			return error;
		unlock = 1;
	}

	generic_fillattr(inode, stat);
	if (unlock)
		gfs2_glock_dq_uninit(&gh);

	return 0;
}

static int gfs2_setxattr(struct dentry *dentry, const char *name,
			 const void *data, size_t size, int flags)
{
	struct inode *inode = dentry->d_inode;
	struct gfs2_ea_request er;

	memset(&er, 0, sizeof(struct gfs2_ea_request));
	er.er_type = gfs2_ea_name2type(name, &er.er_name);
	if (er.er_type == GFS2_EATYPE_UNUSED)
		return -EOPNOTSUPP;
	er.er_data = (char *)data;
	er.er_name_len = strlen(er.er_name);
	er.er_data_len = size;
	er.er_flags = flags;

	gfs2_assert_warn(GFS2_SB(inode), !(er.er_flags & GFS2_ERF_MODE));

	return gfs2_ea_set(GFS2_I(inode), &er);
}

static ssize_t gfs2_getxattr(struct dentry *dentry, const char *name,
			     void *data, size_t size)
{
	struct gfs2_ea_request er;

	memset(&er, 0, sizeof(struct gfs2_ea_request));
	er.er_type = gfs2_ea_name2type(name, &er.er_name);
	if (er.er_type == GFS2_EATYPE_UNUSED)
		return -EOPNOTSUPP;
	er.er_data = data;
	er.er_name_len = strlen(er.er_name);
	er.er_data_len = size;

	return gfs2_ea_get(GFS2_I(dentry->d_inode), &er);
}

static ssize_t gfs2_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
	struct gfs2_ea_request er;

	memset(&er, 0, sizeof(struct gfs2_ea_request));
	er.er_data = (size) ? buffer : NULL;
	er.er_data_len = size;

	return gfs2_ea_list(GFS2_I(dentry->d_inode), &er);
}

static int gfs2_removexattr(struct dentry *dentry, const char *name)
{
	struct gfs2_ea_request er;

	memset(&er, 0, sizeof(struct gfs2_ea_request));
	er.er_type = gfs2_ea_name2type(name, &er.er_name);
	if (er.er_type == GFS2_EATYPE_UNUSED)
		return -EOPNOTSUPP;
	er.er_name_len = strlen(er.er_name);

	return gfs2_ea_remove(GFS2_I(dentry->d_inode), &er);
}

const struct inode_operations gfs2_file_iops = {
	.permission = gfs2_permission,
	.setattr = gfs2_setattr,
	.getattr = gfs2_getattr,
	.setxattr = gfs2_setxattr,
	.getxattr = gfs2_getxattr,
	.listxattr = gfs2_listxattr,
	.removexattr = gfs2_removexattr,
};

const struct inode_operations gfs2_dev_iops = {
	.permission = gfs2_permission,
	.setattr = gfs2_setattr,
	.getattr = gfs2_getattr,
	.setxattr = gfs2_setxattr,
	.getxattr = gfs2_getxattr,
	.listxattr = gfs2_listxattr,
	.removexattr = gfs2_removexattr,
};

const struct inode_operations gfs2_dir_iops = {
	.create = gfs2_create,
	.lookup = gfs2_lookup,
	.link = gfs2_link,
	.unlink = gfs2_unlink,
	.symlink = gfs2_symlink,
	.mkdir = gfs2_mkdir,
	.rmdir = gfs2_rmdir,
	.mknod = gfs2_mknod,
	.rename = gfs2_rename,
	.permission = gfs2_permission,
	.setattr = gfs2_setattr,
	.getattr = gfs2_getattr,
	.setxattr = gfs2_setxattr,
	.getxattr = gfs2_getxattr,
	.listxattr = gfs2_listxattr,
	.removexattr = gfs2_removexattr,
};

const struct inode_operations gfs2_symlink_iops = {
	.readlink = gfs2_readlink,
	.follow_link = gfs2_follow_link,
	.permission = gfs2_permission,
	.setattr = gfs2_setattr,
	.getattr = gfs2_getattr,
	.setxattr = gfs2_setxattr,
	.getxattr = gfs2_getxattr,
	.listxattr = gfs2_listxattr,
	.removexattr = gfs2_removexattr,
};