FreeBSD/Linux Kernel Cross Reference
sys/fs/nfs/unlink.c

     /*
      *  linux/fs/nfs/unlink.c
      *
      * nfs sillydelete handling
      *
      * NOTE: we rely on holding the BKL for list manipulation protection.
      */
     
     #include <linux/slab.h>
    #include <linux/string.h>
    #include <linux/dcache.h>
    #include <linux/sunrpc/sched.h>
    #include <linux/sunrpc/clnt.h>
    #include <linux/nfs_fs.h>
    
    
    struct nfs_unlinkdata {
            struct nfs_unlinkdata   *next;
            struct dentry   *dir, *dentry;
            struct qstr     name;
            struct rpc_task task;
            struct rpc_cred *cred;
            unsigned int    count;
    };
    
    static struct nfs_unlinkdata    *nfs_deletes;
    static RPC_WAITQ(nfs_delete_queue, "nfs_delete_queue");
    
    /**
     * nfs_detach_unlinkdata - Remove asynchronous unlink from global list
     * @data: pointer to descriptor
     */
    static inline void
    nfs_detach_unlinkdata(struct nfs_unlinkdata *data)
    {
            struct nfs_unlinkdata   **q;
    
            for (q = &nfs_deletes; *q != NULL; q = &((*q)->next)) {
                    if (*q == data) {
                            *q = data->next;
                            break;
                    }
            }
    }
    
    /**
     * nfs_put_unlinkdata - release data from a sillydelete operation.
     * @data: pointer to unlink structure.
     */
    static void
    nfs_put_unlinkdata(struct nfs_unlinkdata *data)
    {
            if (--data->count == 0) {
                    nfs_detach_unlinkdata(data);
                    if (data->name.name != NULL)
                            kfree(data->name.name);
                    kfree(data);
            }
    }
    
    #define NAME_ALLOC_LEN(len)     ((len+16) & ~15)
    /**
     * nfs_copy_dname - copy dentry name to data structure
     * @dentry: pointer to dentry
     * @data: nfs_unlinkdata
     */
    static inline void
    nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
    {
            char            *str;
            int             len = dentry->d_name.len;
    
            str = kmalloc(NAME_ALLOC_LEN(len), GFP_KERNEL);
            if (!str)
                    return;
            memcpy(str, dentry->d_name.name, len);
            if (!data->name.len) {
                    data->name.len = len;
                    data->name.name = str;
            } else
                    kfree(str);
    }
    
    /**
     * nfs_async_unlink_init - Initialize the RPC info
     * @task: rpc_task of the sillydelete
     *
     * We delay initializing RPC info until after the call to dentry_iput()
     * in order to minimize races against rename().
     */
    static void
    nfs_async_unlink_init(struct rpc_task *task)
    {
            struct nfs_unlinkdata   *data = (struct nfs_unlinkdata *)task->tk_calldata;
            struct dentry           *dir = data->dir;
            struct rpc_message      msg;
            int                     status = -ENOENT;
    
            if (!data->name.len)
                   goto out_err;
   
           memset(&msg, 0, sizeof(msg));
           msg.rpc_cred = data->cred;
           status = NFS_PROTO(dir->d_inode)->unlink_setup(&msg, dir, &data->name);
           if (status < 0)
                   goto out_err;
           rpc_call_setup(task, &msg, 0);
           return;
    out_err:
           rpc_exit(task, status);
   }
   
   /**
    * nfs_async_unlink_done - Sillydelete post-processing
    * @task: rpc_task of the sillydelete
    *
    * Do the directory attribute update.
    */
   static void
   nfs_async_unlink_done(struct rpc_task *task)
   {
           struct nfs_unlinkdata   *data = (struct nfs_unlinkdata *)task->tk_calldata;
           struct dentry           *dir = data->dir;
           struct inode            *dir_i;
   
           if (nfs_async_handle_jukebox(task))
                   return;
           if (!dir)
                   return;
           dir_i = dir->d_inode;
           nfs_zap_caches(dir_i);
           NFS_PROTO(dir_i)->unlink_done(dir, &task->tk_msg);
           put_rpccred(data->cred);
           data->cred = NULL;
           dput(dir);
   }
   
   /**
    * nfs_async_unlink_release - Release the sillydelete data.
    * @task: rpc_task of the sillydelete
    *
    * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
    * rpc_task would be freed too.
    */
   static void
   nfs_async_unlink_release(struct rpc_task *task)
   {
           struct nfs_unlinkdata   *data = (struct nfs_unlinkdata *)task->tk_calldata;
           nfs_put_unlinkdata(data);
   }
   
   /**
    * nfs_async_unlink - asynchronous unlinking of a file
    * @dir: directory in which the file resides.
    * @name: name of the file to unlink.
    */
   int
   nfs_async_unlink(struct dentry *dentry)
   {
           struct dentry   *dir = dentry->d_parent;
           struct nfs_unlinkdata   *data;
           struct rpc_task *task;
           struct rpc_clnt *clnt = NFS_CLIENT(dir->d_inode);
           int             status = -ENOMEM;
   
           data = kmalloc(sizeof(*data), GFP_KERNEL);
           if (!data)
                   goto out;
           memset(data, 0, sizeof(*data));
   
           data->dir = dget(dir);
           data->dentry = dentry;
   
           data->next = nfs_deletes;
           nfs_deletes = data;
           data->count = 1;
   
           task = &data->task;
           rpc_init_task(task, clnt, nfs_async_unlink_done , RPC_TASK_ASYNC);
           task->tk_calldata = data;
           task->tk_action = nfs_async_unlink_init;
           task->tk_release = nfs_async_unlink_release;
   
           dentry->d_flags |= DCACHE_NFSFS_RENAMED;
           data->cred = rpcauth_lookupcred(clnt->cl_auth, 0);
   
           rpc_sleep_on(&nfs_delete_queue, task, NULL, NULL);
           status = 0;
    out:
           return status;
   }
   
   /**
    * nfs_complete_remove - Initialize completion of the sillydelete
    * @dentry: dentry to delete
    *
    * Since we're most likely to be called by dentry_iput(), we
    * only use the dentry to find the sillydelete. We then copy the name
    * into the qstr.
    */
   void
   nfs_complete_unlink(struct dentry *dentry)
   {
           struct nfs_unlinkdata   *data;
   
           for(data = nfs_deletes; data != NULL; data = data->next) {
                   if (dentry == data->dentry)
                           break;
           }
           if (!data)
                   return;
           data->count++;
           nfs_copy_dname(dentry, data);
           dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
           if (data->task.tk_rpcwait == &nfs_delete_queue)
                   rpc_wake_up_task(&data->task);
           nfs_put_unlinkdata(data);
   }

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