text: // SPDX-License-Identifier: GPL-2.0-or-later
  /* Fileserver-directed operation handling.
   *
   * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   */
  
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/fs.h>
  #include "internal.h"
  
  static atomic_t afs_operation_debug_counter;
  
  /*
   * Create an operation against a volume.
   */
  struct afs_operation *afs_alloc_operation(struct key *key, struct afs_volume *volume)
  {
  	struct afs_operation *op;
  
  	_enter("");
  
  	op = kzalloc(sizeof(*op), GFP_KERNEL);
  	if (!op)
  		return ERR_PTR(-ENOMEM);
  
  	if (!key) {
  		key = afs_request_key(volume->cell);
  		if (IS_ERR(key)) {
  			kfree(op);
  			return ERR_CAST(key);
  		}
  	} else {
  		key_get(key);
  	}
  
  	op->key		= key;
  	op->volume	= afs_get_volume(volume, afs_volume_trace_get_new_op);
  	op->net		= volume->cell->net;
  	op->cb_v_break	= volume->cb_v_break;
  	op->debug_id	= atomic_inc_return(&afs_operation_debug_counter);
  	op->error	= -EDESTADDRREQ;
  	op->ac.error	= SHRT_MAX;
  
  	_leave(" = [op=%08x]", op->debug_id);
  	return op;
  }
  
  /*
   * Lock the vnode(s) being operated upon.
   */
  static bool afs_get_io_locks(struct afs_operation *op)
  {
  	struct afs_vnode *vnode = op->file[0].vnode;
  	struct afs_vnode *vnode2 = op->file[1].vnode;
  
  	_enter("");
  
  	if (op->flags & AFS_OPERATION_UNINTR) {
  		mutex_lock(&vnode->io_lock);
  		op->flags |= AFS_OPERATION_LOCK_0;
  		_leave(" = t [1]");
  		return true;
  	}
  
  	if (!vnode2 || !op->file[1].need_io_lock || vnode == vnode2)
  		vnode2 = NULL;
  
  	if (vnode2 > vnode)
  		swap(vnode, vnode2);
  
  	if (mutex_lock_interruptible(&vnode->io_lock) < 0) {
  		op->error = -ERESTARTSYS;
  		op->flags |= AFS_OPERATION_STOP;
  		_leave(" = f [I 0]");
  		return false;
  	}
  	op->flags |= AFS_OPERATION_LOCK_0;
  
  	if (vnode2) {
  		if (mutex_lock_interruptible_nested(&vnode2->io_lock, 1) < 0) {
  			op->error = -ERESTARTSYS;
  			op->flags |= AFS_OPERATION_STOP;
  			mutex_unlock(&vnode->io_lock);
  			op->flags &= ~AFS_OPERATION_LOCK_0;
  			_leave(" = f [I 1]");
  			return false;
  		}
  		op->flags |= AFS_OPERATION_LOCK_1;
  	}
  
  	_leave(" = t [2]");
  	return true;
  }
  
  static void afs_drop_io_locks(struct afs_operation *op)
  {
  	struct afs_vnode *vnode = op->file[0].vnode;
  	struct afs_vnode *vnode2 = op->file[1].vnode;
  
  	_enter("");
  
  	if (op->flags & AFS_OPERATION_LOCK_1)
  		mutex_unlock(&vnode2->io_lock);
  	if (op->flags & AFS_OPERATION_LOCK_0)
  		mutex_unlock(&vnode->io_lock);
  }
  
  static void afs_prepare_vnode(struct afs_operation *op, struct afs_vnode_param *vp,
  			      unsigned int index)
  {
  	struct afs_vnode *vnode = vp->vnode;
  
  	if (vnode) {
  		vp->fid			= vnode->fid;
  		vp->dv_before		= vnode->status.data_version;
  		vp->cb_break_before	= afs_calc_vnode_cb_break(vnode);
  		if (vnode->lock_state != AFS_VNODE_LOCK_NONE)
  			op->flags	|= AFS_OPERATION_CUR_ONLY;
  		if (vp->modification)
  			set_bit(AFS_VNODE_MODIFYING, &vnode->flags);
  	}
  
  	if (vp->fid.vnode)
  		_debug("PREP[%u] {%llx:%llu.%u}",
  		       index, vp->fid.vid, vp->fid.vnode, vp->fid.unique);
  }
  
  /*
   * Begin an operation on the fileserver.
   *
   * Fileserver operations are serialised on the server by vnode, so we serialise
   * them here also using the io_lock.
   */
  bool afs_begin_vnode_operation(struct afs_operation *op)
  {
  	struct afs_vnode *vnode = op->file[0].vnode;
  
  	ASSERT(vnode);
  
  	_enter("");
  
  	if (op->file[0].need_io_lock)
  		if (!afs_get_io_locks(op))
  			return false;
  
  	afs_prepare_vnode(op, &op->file[0], 0);
  	afs_prepare_vnode(op, &op->file[1], 1);
  	op->cb_v_break = op->volume->cb_v_break;
  	_leave(" = true");
  	return true;
  }
  
  /*
   * Tidy up a filesystem cursor and unlock the vnode.
   */
  static void afs_end_vnode_operation(struct afs_operation *op)
  {
  	_enter("");
  
  	if (op->error == -EDESTADDRREQ ||
  	    op->error == -EADDRNOTAVAIL ||
  	    op->error == -ENETUNREACH ||
  	    op->error == -EHOSTUNREACH)
  		afs_dump_edestaddrreq(op);
  
  	afs_drop_io_locks(op);
  
  	if (op->error == -ECONNABORTED)
  		op->error = afs_abort_to_error(op->ac.abort_code);
  }
  
  /*
   * Wait for an in-progress operation to complete.
   */
  void afs_wait_for_operation(struct afs_operation *op)
  {
  	_enter("");
  
  	while (afs_select_fileserver(op)) {
  		op->cb_s_break = op->server->cb_s_break;
  		if (test_bit(AFS_SERVER_FL_IS_YFS, &op->server->flags) &&
  		    op->ops->issue_yfs_rpc)
  			op->ops->issue_yfs_rpc(op);
  		else if (op->ops->issue_afs_rpc)
  			op->ops->issue_afs_rpc(op);
  		else
  			op->ac.error = -ENOTSUPP;
  
  		if (op->call)
  			op->error = afs_wait_for_call_to_complete(op->call, &op->ac);
  	}
  
  	switch (op->error) {
  	case 0:
  		_debug("success");
  		op->ops->success(op);
  		break;
  	case -ECONNABORTED:
  		if (op->ops->aborted)
  			op->ops->aborted(op);
  		break;
  	default:
  		break;
  	}
  
  	afs_end_vnode_operation(op);
  
  	if (op->error == 0 && op->ops->edit_dir) {
  		_debug("edit_dir");
  		op->ops->edit_dir(op);
  	}
  	_leave("");
  }
  
  /*
   * Dispose of an operation.
   */
  int afs_put_operation(struct afs_operation *op)
  {
  	int i, ret = op->error;
  
  	_enter("op=%08x,%d", op->debug_id, ret);
  
  	if (op->ops && op->ops->put)
  		op->ops->put(op);
  	if (op->file[0].modification)
  		clear_bit(AFS_VNODE_MODIFYING, &op->file[0].vnode->flags);
  	if (op->file[1].modification && op->file[1].vnode != op->file[0].vnode)
  		clear_bit(AFS_VNODE_MODIFYING, &op->file[1].vnode->flags);
  	if (op->file[0].put_vnode)
  		iput(&op->file[0].vnode->vfs_inode);
  	if (op->file[1].put_vnode)
  		iput(&op->file[1].vnode->vfs_inode);
  
  	if (op->more_files) {
  		for (i = 0; i < op->nr_files - 2; i++)
  			if (op->more_files[i].put_vnode)
  				iput(&op->more_files[i].vnode->vfs_inode);
  		kfree(op->more_files);
  	}
  
  	afs_end_cursor(&op->ac);
  	afs_put_serverlist(op->net, op->server_list);
  	afs_put_volume(op->net, op->volume, afs_volume_trace_put_put_op);
  	key_put(op->key);
  	kfree(op);
  	return ret;
  }
  
  int afs_do_sync_operation(struct afs_operation *op)
  {
  	afs_begin_vnode_operation(op);
  	afs_wait_for_operation(op);
  	return afs_put_operation(op);
  }
  