fix: 修复NFS使用不可靠父节点信息的错误

NFS的read/write/readpage/writepage接口在读写数据前会尝试更新当前节点的fhandle，更新时会取用父节点vnode的私有数据。
此时如果父节点已经被释放，则可能导致访问空指针或错误数据。因此需要将父节点fhandle保存在当前节点私有数据中。

Close #I4EZ0V
Signed-off-by: NFar <yesiyuan2@huawei.com>

fs/nfs/nfs_adapter.c

@@ -824,6 +824,7 @@ int vfs_nfs_mount(struct Mount *mnt, struct Vnode *device, const void *data)
   vp->data = root;
   root->n_fhsize = nmp->nm_fhsize;
   (void)memcpy_s(&(root->n_fhandle), root->n_fhsize, &(nmp->nm_fh), nmp->nm_fhsize);
+  root->n_pfhsize = 0;
   mnt->vnodeCovered = vp;
   mnt->data = nmp;
   root->n_next = nmp->nm_head;
@@ -874,6 +875,8 @@ int vfs_nfs_lookup(struct Vnode *parent, const char *path, int len, struct Vnode
   nfs_node = zalloc(sizeof(struct nfsnode));
   nfs_node->n_fhsize = (uint8_t)fhandle.length;
   memcpy_s(&(nfs_node->n_fhandle), nfs_node->n_fhsize, &(fhandle.handle), fhandle.length);
+  nfs_node->n_pfhsize = parent_nfs_node->n_fhsize;
+  (void)memcpy_s(&(nfs_node->n_pfhandle), NFSX_V3FHMAX, &(parent_nfs_node->n_fhandle), parent_nfs_node->n_fhsize);
   nfs_node->n_name = zalloc(sizeof(filename));
   memcpy_s(nfs_node->n_name, (len + 1), filename, sizeof(filename));
   nfs_node->n_next = nmp->nm_head;
@@ -1523,6 +1526,8 @@ int vfs_nfs_mkdir(struct Vnode *parent, const char *dirname, mode_t mode, struct
   target_node = zalloc(sizeof(struct nfsnode));
   target_node->n_fhsize = (uint8_t)fhandle.length;
   memcpy_s(&(target_node->n_fhandle), target_node->n_fhsize, &(fhandle.handle), fhandle.length);
+  target_node->n_pfhsize = parent_nfs_node->n_fhsize;
+  (void)memcpy_s(&(target_node->n_pfhandle), NFSX_V3FHMAX, &(parent_nfs_node->n_fhandle), parent_nfs_node->n_fhsize);
   target_node->n_name = zalloc(sizeof (dirname));
   memcpy_s(target_node->n_name, sizeof(dirname), dirname, sizeof (dirname));
   target_node->n_next = nmp->nm_head;
@@ -1576,10 +1581,10 @@ int vfs_nfs_write(struct file *filep, const char *buffer, size_t buflen)
       goto errout_with_mutex;
     }
 
-  parent_fhandle.length = ((struct nfsnode *)node->parent->data)->n_fhsize;
-  memcpy_s(&(parent_fhandle.handle), parent_fhandle.length,
-      &(((struct nfsnode *)node->parent->data)->n_fhandle),
-      ((struct nfsnode *)node->parent->data)->n_fhsize);
+  parent_fhandle.length = ((struct nfsnode *)node->data)->n_pfhsize;
+  (void)memcpy_s(&(parent_fhandle.handle), NFSX_V3FHMAX,
+      &(((struct nfsnode *)node->data)->n_pfhandle),
+      ((struct nfsnode *)node->data)->n_pfhsize);
 
   if (filep->f_oflags & O_APPEND)
     {
@@ -1794,10 +1799,10 @@ ssize_t vfs_nfs_writepage(struct Vnode *node, char *buffer, off_t pos, size_t bu
       goto errout_with_mutex;
     }
 
-  parent_fhandle.length = ((struct nfsnode *)node->parent->data)->n_fhsize;
-  memcpy_s(&(parent_fhandle.handle), parent_fhandle.length,
-      &(((struct nfsnode *)node->parent->data)->n_fhandle),
-      ((struct nfsnode *)node->parent->data)->n_fhsize);
+  parent_fhandle.length = ((struct nfsnode *)node->data)->n_pfhsize;
+  (void)memcpy_s(&(parent_fhandle.handle), NFSX_V3FHMAX,
+      &(((struct nfsnode *)node->data)->n_pfhandle),
+      ((struct nfsnode *)node->data)->n_pfhsize);
 
   /* Check if the file size would exceed the range of off_t */
 
@@ -2066,10 +2071,10 @@ ssize_t vfs_nfs_readpage(struct Vnode *node, char *buffer, off_t pos)
     }
 
 
-  parent_fhandle.length = ((struct nfsnode *)node->parent->data)->n_fhsize;
-  memcpy_s(&(parent_fhandle.handle), parent_fhandle.length,
-      &(((struct nfsnode *)node->parent->data)->n_fhandle),
-      ((struct nfsnode *)node->parent->data)->n_fhsize);
+  parent_fhandle.length = ((struct nfsnode *)node->data)->n_pfhsize;
+  (void)memcpy_s(&(parent_fhandle.handle), NFSX_V3FHMAX,
+      &(((struct nfsnode *)node->data)->n_pfhandle),
+      ((struct nfsnode *)node->data)->n_pfhsize);
   error = nfs_fileupdate(nmp, np->n_name, &parent_fhandle, np);
   if (error != OK)
     {
@@ -2217,10 +2222,10 @@ ssize_t vfs_nfs_read(struct file *filep, char *buffer, size_t buflen)
     }
 
 
-  parent_fhandle.length = ((struct nfsnode *)node->parent->data)->n_fhsize;
-  memcpy_s(&(parent_fhandle.handle), parent_fhandle.length,
-      &(((struct nfsnode *)node->parent->data)->n_fhandle),
-      ((struct nfsnode *)node->parent->data)->n_fhsize);
+  parent_fhandle.length = ((struct nfsnode *)node->data)->n_pfhsize;
+  (void)memcpy_s(&(parent_fhandle.handle), NFSX_V3FHMAX,
+      &(((struct nfsnode *)node->data)->n_pfhandle),
+      ((struct nfsnode *)node->data)->n_pfhsize);
   error = nfs_fileupdate(nmp, np->n_name, &parent_fhandle, np);
   if (error != OK)
     {
@@ -2497,6 +2502,9 @@ int vfs_nfs_create(struct Vnode *parent, const char *filename, int mode, struct
   np->n_next   = nmp->nm_head;
   nmp->nm_head = np;
 
+  np->n_pfhsize     = parent_nfs_node->n_fhsize;
+  (void)memcpy_s(&(np->n_pfhandle), NFSX_V3FHMAX, &(parent_nfs_node->n_fhandle), parent_nfs_node->n_fhsize);
+
   np->n_flags |= (NFSNODE_OPEN | NFSNODE_MODIFIED);
   np->n_name = zalloc(namelen + 1);
   memcpy_s(np->n_name, (namelen + 1), filename, (namelen + 1));

fs/nfs/nfs_node.h

@@ -79,12 +79,14 @@ struct nfsnode
   uint8_t            n_crefs;       /* Reference count (for nfs_dup) */
   uint8_t            n_type;        /* File type */
   uint8_t            n_fhsize;      /* Size in bytes of the file handle */
+  uint8_t            n_pfhsize;     /* Size in bytes of the file handle of parent */
   uint8_t            n_flags;       /* Node flags */
   uint16_t           n_mode;        /* File mode for fstat() */
   time_t             n_atime;       /* File access time */
   time_t             n_mtime;       /* File modification time */
   time_t             n_ctime;       /* File creation time */
   nfsfh_t            n_fhandle;     /* NFS File Handle */
+  nfsfh_t            n_pfhandle;    /* NFS File Handle of parent */
   uint64_t           n_size;        /* Current size of file */
   int                n_oflags;      /* Flags provided when file was opened */
   loff_t             n_fpos;        /* NFS File position */