dir.c

linux 内核源代码

	vnode = AFS_FS_I(dentry->d_inode);

	if (dentry->d_inode)
		_enter("{v={%x:%u} n=%s fl=%lx},",
		       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
		       vnode->flags);
	else
		_enter("{neg n=%s}", dentry->d_name.name);

	key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);
	if (IS_ERR(key))
		key = NULL;

	/* lock down the parent dentry so we can peer at it */
	parent = dget_parent(dentry);
	if (!parent->d_inode)
		goto out_bad;

	dir = AFS_FS_I(parent->d_inode);

	/* validate the parent directory */
	if (test_bit(AFS_VNODE_MODIFIED, &dir->flags))
		afs_validate(dir, key);

	if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {
		_debug("%s: parent dir deleted", dentry->d_name.name);
		goto out_bad;
	}

	dir_version = (void *) (unsigned long) dir->status.data_version;
	if (dentry->d_fsdata == dir_version)
		goto out_valid; /* the dir contents are unchanged */

	_debug("dir modified");

	/* search the directory for this vnode */
	ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);
	switch (ret) {
	case 0:
		/* the filename maps to something */
		if (!dentry->d_inode)
			goto out_bad;
		if (is_bad_inode(dentry->d_inode)) {
			printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n",
			       parent->d_name.name, dentry->d_name.name);
			goto out_bad;
		}

		/* if the vnode ID has changed, then the dirent points to a
		 * different file */
		if (fid.vnode != vnode->fid.vnode) {
			_debug("%s: dirent changed [%u != %u]",
			       dentry->d_name.name, fid.vnode,
			       vnode->fid.vnode);
			goto not_found;
		}

		/* if the vnode ID uniqifier has changed, then the file has
		 * been deleted and replaced, and the original vnode ID has
		 * been reused */
		if (fid.unique != vnode->fid.unique) {
			_debug("%s: file deleted (uq %u -> %u I:%lu)",
			       dentry->d_name.name, fid.unique,
			       vnode->fid.unique, dentry->d_inode->i_version);
			spin_lock(&vnode->lock);
			set_bit(AFS_VNODE_DELETED, &vnode->flags);
			spin_unlock(&vnode->lock);
			goto not_found;
		}
		goto out_valid;

	case -ENOENT:
		/* the filename is unknown */
		_debug("%s: dirent not found", dentry->d_name.name);
		if (dentry->d_inode)
			goto not_found;
		goto out_valid;

	default:
		_debug("failed to iterate dir %s: %d",
		       parent->d_name.name, ret);
		goto out_bad;
	}

out_valid:
	dentry->d_fsdata = dir_version;
out_skip:
	dput(parent);
	key_put(key);
	_leave(" = 1 [valid]");
	return 1;

	/* the dirent, if it exists, now points to a different vnode */
not_found:
	spin_lock(&dentry->d_lock);
	dentry->d_flags |= DCACHE_NFSFS_RENAMED;
	spin_unlock(&dentry->d_lock);

out_bad:
	if (dentry->d_inode) {
		/* don't unhash if we have submounts */
		if (have_submounts(dentry))
			goto out_skip;
	}

	_debug("dropping dentry %s/%s",
	       parent->d_name.name, dentry->d_name.name);
	shrink_dcache_parent(dentry);
	d_drop(dentry);
	dput(parent);
	key_put(key);

	_leave(" = 0 [bad]");
	return 0;
}

/*
 * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
 * sleep)
 * - called from dput() when d_count is going to 0.
 * - return 1 to request dentry be unhashed, 0 otherwise
 */
static int afs_d_delete(struct dentry *dentry)
{
	_enter("%s", dentry->d_name.name);

	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
		goto zap;

	if (dentry->d_inode &&
	    test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dentry->d_inode)->flags))
			goto zap;

	_leave(" = 0 [keep]");
	return 0;

zap:
	_leave(" = 1 [zap]");
	return 1;
}

/*
 * handle dentry release
 */
static void afs_d_release(struct dentry *dentry)
{
	_enter("%s", dentry->d_name.name);
}

/*
 * create a directory on an AFS filesystem
 */
static int afs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
	struct afs_file_status status;
	struct afs_callback cb;
	struct afs_server *server;
	struct afs_vnode *dvnode, *vnode;
	struct afs_fid fid;
	struct inode *inode;
	struct key *key;
	int ret;

	dvnode = AFS_FS_I(dir);

	_enter("{%x:%u},{%s},%o",
	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name, mode);

	ret = -ENAMETOOLONG;
	if (dentry->d_name.len >= AFSNAMEMAX)
		goto error;

	key = afs_request_key(dvnode->volume->cell);
	if (IS_ERR(key)) {
		ret = PTR_ERR(key);
		goto error;
	}

	mode |= S_IFDIR;
	ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
			       mode, &fid, &status, &cb, &server);
	if (ret < 0)
		goto mkdir_error;

	inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
	if (IS_ERR(inode)) {
		/* ENOMEM at a really inconvenient time - just abandon the new
		 * directory on the server */
		ret = PTR_ERR(inode);
		goto iget_error;
	}

	/* apply the status report we've got for the new vnode */
	vnode = AFS_FS_I(inode);
	spin_lock(&vnode->lock);
	vnode->update_cnt++;
	spin_unlock(&vnode->lock);
	afs_vnode_finalise_status_update(vnode, server);
	afs_put_server(server);

	d_instantiate(dentry, inode);
	if (d_unhashed(dentry)) {
		_debug("not hashed");
		d_rehash(dentry);
	}
	key_put(key);
	_leave(" = 0");
	return 0;

iget_error:
	afs_put_server(server);
mkdir_error:
	key_put(key);
error:
	d_drop(dentry);
	_leave(" = %d", ret);
	return ret;
}

/*
 * remove a directory from an AFS filesystem
 */
static int afs_rmdir(struct inode *dir, struct dentry *dentry)
{
	struct afs_vnode *dvnode, *vnode;
	struct key *key;
	int ret;

	dvnode = AFS_FS_I(dir);

	_enter("{%x:%u},{%s}",
	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name);

	ret = -ENAMETOOLONG;
	if (dentry->d_name.len >= AFSNAMEMAX)
		goto error;

	key = afs_request_key(dvnode->volume->cell);
	if (IS_ERR(key)) {
		ret = PTR_ERR(key);
		goto error;
	}

	ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, true);
	if (ret < 0)
		goto rmdir_error;

	if (dentry->d_inode) {
		vnode = AFS_FS_I(dentry->d_inode);
		clear_nlink(&vnode->vfs_inode);
		set_bit(AFS_VNODE_DELETED, &vnode->flags);
		afs_discard_callback_on_delete(vnode);
	}

	key_put(key);
	_leave(" = 0");
	return 0;

rmdir_error:
	key_put(key);
error:
	_leave(" = %d", ret);
	return ret;
}

/*
 * remove a file from an AFS filesystem
 */
static int afs_unlink(struct inode *dir, struct dentry *dentry)
{
	struct afs_vnode *dvnode, *vnode;
	struct key *key;
	int ret;

	dvnode = AFS_FS_I(dir);

	_enter("{%x:%u},{%s}",
	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name);

	ret = -ENAMETOOLONG;
	if (dentry->d_name.len >= AFSNAMEMAX)
		goto error;

	key = afs_request_key(dvnode->volume->cell);
	if (IS_ERR(key)) {
		ret = PTR_ERR(key);
		goto error;
	}

	if (dentry->d_inode) {
		vnode = AFS_FS_I(dentry->d_inode);

		/* make sure we have a callback promise on the victim */
		ret = afs_validate(vnode, key);
		if (ret < 0)
			goto error;
	}

	ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, false);
	if (ret < 0)
		goto remove_error;

	if (dentry->d_inode) {
		/* if the file wasn't deleted due to excess hard links, the
		 * fileserver will break the callback promise on the file - if
		 * it had one - before it returns to us, and if it was deleted,
		 * it won't
		 *
		 * however, if we didn't have a callback promise outstanding,
		 * or it was outstanding on a different server, then it won't
		 * break it either...
		 */
		vnode = AFS_FS_I(dentry->d_inode);
		if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
			_debug("AFS_VNODE_DELETED");
		if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags))
			_debug("AFS_VNODE_CB_BROKEN");
		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
		ret = afs_validate(vnode, key);
		_debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, ret);
	}

	key_put(key);
	_leave(" = 0");
	return 0;

remove_error:
	key_put(key);
error:
	_leave(" = %d", ret);
	return ret;
}

/*
 * create a regular file on an AFS filesystem
 */
static int afs_create(struct inode *dir, struct dentry *dentry, int mode,
		      struct nameidata *nd)
{
	struct afs_file_status status;
	struct afs_callback cb;
	struct afs_server *server;
	struct afs_vnode *dvnode, *vnode;
	struct afs_fid fid;
	struct inode *inode;
	struct key *key;
	int ret;

	dvnode = AFS_FS_I(dir);

	_enter("{%x:%u},{%s},%o,",
	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name, mode);

	ret = -ENAMETOOLONG;
	if (dentry->d_name.len >= AFSNAMEMAX)
		goto error;

	key = afs_request_key(dvnode->volume->cell);
	if (IS_ERR(key)) {
		ret = PTR_ERR(key);
		goto error;
	}

	mode |= S_IFREG;
	ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
			       mode, &fid, &status, &cb, &server);
	if (ret < 0)
		goto create_error;

	inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
	if (IS_ERR(inode)) {
		/* ENOMEM at a really inconvenient time - just abandon the new
		 * directory on the server */
		ret = PTR_ERR(inode);
		goto iget_error;
	}

	/* apply the status report we've got for the new vnode */
	vnode = AFS_FS_I(inode);
	spin_lock(&vnode->lock);
	vnode->update_cnt++;
	spin_unlock(&vnode->lock);
	afs_vnode_finalise_status_update(vnode, server);
	afs_put_server(server);

	d_instantiate(dentry, inode);
	if (d_unhashed(dentry)) {
		_debug("not hashed");
		d_rehash(dentry);
	}
	key_put(key);
	_leave(" = 0");
	return 0;

iget_error:
	afs_put_server(server);
create_error:
	key_put(key);
error:
	d_drop(dentry);
	_leave(" = %d", ret);
	return ret;
}

/*
 * create a hard link between files in an AFS filesystem
 */
static int afs_link(struct dentry *from, struct inode *dir,
		    struct dentry *dentry)
{
	struct afs_vnode *dvnode, *vnode;
	struct key *key;
	int ret;

	vnode = AFS_FS_I(from->d_inode);
	dvnode = AFS_FS_I(dir);

	_enter("{%x:%u},{%x:%u},{%s}",
	       vnode->fid.vid, vnode->fid.vnode,
	       dvnode->fid.vid, dvnode->fid.vnode,
	       dentry->d_name.name);

	ret = -ENAMETOOLONG;
	if (dentry->d_name.len >= AFSNAMEMAX)
		goto error;

	key = afs_request_key(dvnode->volume->cell);
	if (IS_ERR(key)) {
		ret = PTR_ERR(key);
		goto error;
	}

	ret = afs_vnode_link(dvnode, vnode, key, dentry->d_name.name);
	if (ret < 0)
		goto link_error;

	atomic_inc(&vnode->vfs_inode.i_count);
	d_instantiate(dentry, &vnode->vfs_inode);
	key_put(key);
	_leave(" = 0");
	return 0;

link_error:
	key_put(key);
error:
	d_drop(dentry);
	_leave(" = %d", ret);
	return ret;
}

/*
 * create a symlink in an AFS filesystem
 */
static int afs_symlink(struct inode *dir, struct dentry *dentry,
		       const char *content)
{
	struct afs_file_status status;
	struct afs_server *server;
	struct afs_vnode *dvnode, *vnode;
	struct afs_fid fid;
	struct inode *inode;
	struct key *key;
	int ret;

	dvnode = AFS_FS_I(dir);

	_enter("{%x:%u},{%s},%s",
	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name,
	       content);

	ret = -ENAMETOOLONG;
	if (dentry->d_name.len >= AFSNAMEMAX)
		goto error;

	ret = -EINVAL;
	if (strlen(content) >= AFSPATHMAX)
		goto error;

	key = afs_request_key(dvnode->volume->cell);
	if (IS_ERR(key)) {
		ret = PTR_ERR(key);
		goto error;
	}

	ret = afs_vnode_symlink(dvnode, key, dentry->d_name.name, content,
				&fid, &status, &server);
	if (ret < 0)
		goto create_error;

	inode = afs_iget(dir->i_sb, key, &fid, &status, NULL);
	if (IS_ERR(inode)) {
		/* ENOMEM at a really inconvenient time - just abandon the new
		 * directory on the server */
		ret = PTR_ERR(inode);
		goto iget_error;
	}

	/* apply the status report we've got for the new vnode */
	vnode = AFS_FS_I(inode);
	spin_lock(&vnode->lock);
	vnode->update_cnt++;
	spin_unlock(&vnode->lock);
	afs_vnode_finalise_status_update(vnode, server);
	afs_put_server(server);

	d_instantiate(dentry, inode);
	if (d_unhashed(dentry)) {
		_debug("not hashed");
		d_rehash(dentry);
	}
	key_put(key);
	_leave(" = 0");
	return 0;

iget_error:
	afs_put_server(server);
create_error:
	key_put(key);
error:
	d_drop(dentry);
	_leave(" = %d", ret);
	return ret;
}

/*
 * rename a file in an AFS filesystem and/or move it between directories
 */
static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
		      struct inode *new_dir, struct dentry *new_dentry)
{
	struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
	struct key *key;
	int ret;

	vnode = AFS_FS_I(old_dentry->d_inode);
	orig_dvnode = AFS_FS_I(old_dir);
	new_dvnode = AFS_FS_I(new_dir);

	_enter("{%x:%u},{%x:%u},{%x:%u},{%s}",
	       orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
	       vnode->fid.vid, vnode->fid.vnode,
	       new_dvnode->fid.vid, new_dvnode->fid.vnode,
	       new_dentry->d_name.name);

	ret = -ENAMETOOLONG;
	if (new_dentry->d_name.len >= AFSNAMEMAX)
		goto error;

	key = afs_request_key(orig_dvnode->volume->cell);
	if (IS_ERR(key)) {
		ret = PTR_ERR(key);
		goto error;
	}

	ret = afs_vnode_rename(orig_dvnode, new_dvnode, key,
			       old_dentry->d_name.name,
			       new_dentry->d_name.name);
	if (ret < 0)
		goto rename_error;
	key_put(key);
	_leave(" = 0");
	return 0;

rename_error:
	key_put(key);
error:
	d_drop(new_dentry);
	_leave(" = %d", ret);
	return ret;
}