4cec713dbf
Summary: 1.Modified the i_crefs from int16_t to atomic_int 2.Modified the i_crefs add, delete, read, and initialize interfaces to atomic operations The purpose of this change is to avoid deadlock in cross-core scenarios, where A Core blocks B Core’s request for a write operation to A Core when A Core requests a read operation to B Core. Signed-off-by: chenrun1 <chenrun1@xiaomi.com>
158 lines
4.6 KiB
C
158 lines
4.6 KiB
C
/****************************************************************************
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* fs/inode/fs_inoderemove.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <assert.h>
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#include <errno.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/fs/fs.h>
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#include "inode/inode.h"
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: inode_unlink
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*
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* Description:
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* Given a path, remove a the node from the in-memory, inode tree that the
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* path refers to. This is normally done in preparation to removing or
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* moving an inode.
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*
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* In symbolic links in the pseduo file system are enabled, then this
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* logic will follow the symbolic links up until the terminal node. Then
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* that link in removed. So if this the terminal node is a symbolic link,
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* the symbolic link node will be removed, not the target of the link.
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*
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* Assumptions/Limitations:
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* The caller must hold the inode semaphore
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*
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****************************************************************************/
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static FAR struct inode *inode_unlink(FAR const char *path)
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{
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struct inode_search_s desc;
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FAR struct inode *node = NULL;
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int ret;
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/* Verify parameters. Ignore null paths */
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if (path == NULL)
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{
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return NULL;
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}
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/* Find the node to unlink */
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SETUP_SEARCH(&desc, path, true);
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ret = inode_search(&desc);
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if (ret >= 0)
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{
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node = desc.node;
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DEBUGASSERT(node != NULL);
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/* If peer is non-null, then remove the node from the right of
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* of that peer node.
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*/
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if (desc.peer != NULL)
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{
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desc.peer->i_peer = node->i_peer;
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}
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/* Then remove the node from head of the list of children. */
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else
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{
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DEBUGASSERT(desc.parent != NULL);
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desc.parent->i_child = node->i_peer;
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}
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node->i_peer = NULL;
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node->i_parent = NULL;
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atomic_fetch_sub(&node->i_crefs, 1);
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}
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RELEASE_SEARCH(&desc);
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return node;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: inode_remove
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*
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* Description:
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* Given a path, remove a the node from the in-memory, inode tree that the
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* path refers to and free all resources related to the inode. If the
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* inode is in-use, then it will be unlinked, but will not be freed until
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* the last reference to the inode is released.
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*
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* Assumptions/Limitations:
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* The caller must hold the inode semaphore
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*
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****************************************************************************/
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int inode_remove(FAR const char *path)
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{
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FAR struct inode *node;
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/* Find the inode and unlink it from the in-memory inode tree */
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node = inode_unlink(path);
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if (node)
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{
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/* Found it! But we cannot delete the inode if there are references
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* to it
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*/
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if (atomic_load(&node->i_crefs))
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{
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return -EBUSY;
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}
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else
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{
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/* And delete it now -- recursively to delete all of its children.
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* Since it has been unlinked, then the peer pointer should be
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* NULL.
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*/
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DEBUGASSERT(node->i_peer == NULL);
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inode_free(node);
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return OK;
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}
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}
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/* The node does not exist */
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return -ENOENT;
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}
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