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![Thomas Gleixner](/assets/img/avatar_default.png)
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public licence as published by the free software foundation either version 2 of the licence or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 114 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
250 lines
6.5 KiB
C
250 lines
6.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* AFS silly rename handling
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*
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* Copyright (C) 2019 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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* - Derived from NFS's sillyrename.
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*/
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include <linux/fsnotify.h>
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#include "internal.h"
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/*
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* Actually perform the silly rename step.
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*/
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static int afs_do_silly_rename(struct afs_vnode *dvnode, struct afs_vnode *vnode,
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struct dentry *old, struct dentry *new,
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struct key *key)
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{
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struct afs_fs_cursor fc;
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struct afs_status_cb *scb;
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int ret = -ERESTARTSYS;
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_enter("%pd,%pd", old, new);
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scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL);
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if (!scb)
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return -ENOMEM;
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trace_afs_silly_rename(vnode, false);
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if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
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afs_dataversion_t dir_data_version = dvnode->status.data_version + 1;
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while (afs_select_fileserver(&fc)) {
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fc.cb_break = afs_calc_vnode_cb_break(dvnode);
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afs_fs_rename(&fc, old->d_name.name,
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dvnode, new->d_name.name,
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scb, scb);
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}
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afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
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&dir_data_version, scb);
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ret = afs_end_vnode_operation(&fc);
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}
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if (ret == 0) {
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spin_lock(&old->d_lock);
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old->d_flags |= DCACHE_NFSFS_RENAMED;
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spin_unlock(&old->d_lock);
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if (dvnode->silly_key != key) {
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key_put(dvnode->silly_key);
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dvnode->silly_key = key_get(key);
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}
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if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
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afs_edit_dir_remove(dvnode, &old->d_name,
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afs_edit_dir_for_silly_0);
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if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
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afs_edit_dir_add(dvnode, &new->d_name,
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&vnode->fid, afs_edit_dir_for_silly_1);
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/* vfs_unlink and the like do not issue this when a file is
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* sillyrenamed, so do it here.
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*/
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fsnotify_nameremove(old, 0);
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}
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kfree(scb);
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_leave(" = %d", ret);
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return ret;
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}
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/**
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* afs_sillyrename - Perform a silly-rename of a dentry
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*
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* AFS is stateless and the server doesn't know when the client is holding a
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* file open. To prevent application problems when a file is unlinked while
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* it's still open, the client performs a "silly-rename". That is, it renames
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* the file to a hidden file in the same directory, and only performs the
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* unlink once the last reference to it is put.
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*
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* The final cleanup is done during dentry_iput.
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*/
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int afs_sillyrename(struct afs_vnode *dvnode, struct afs_vnode *vnode,
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struct dentry *dentry, struct key *key)
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{
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static unsigned int sillycounter;
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struct dentry *sdentry = NULL;
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unsigned char silly[16];
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int ret = -EBUSY;
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_enter("");
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/* We don't allow a dentry to be silly-renamed twice. */
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if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
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return -EBUSY;
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sdentry = NULL;
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do {
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int slen;
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dput(sdentry);
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sillycounter++;
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/* Create a silly name. Note that the ".__afs" prefix is
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* understood by the salvager and must not be changed.
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*/
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slen = scnprintf(silly, sizeof(silly), ".__afs%04X", sillycounter);
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sdentry = lookup_one_len(silly, dentry->d_parent, slen);
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/* N.B. Better to return EBUSY here ... it could be dangerous
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* to delete the file while it's in use.
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*/
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if (IS_ERR(sdentry))
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goto out;
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} while (!d_is_negative(sdentry));
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ihold(&vnode->vfs_inode);
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ret = afs_do_silly_rename(dvnode, vnode, dentry, sdentry, key);
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switch (ret) {
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case 0:
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/* The rename succeeded. */
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d_move(dentry, sdentry);
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break;
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case -ERESTARTSYS:
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/* The result of the rename is unknown. Play it safe by forcing
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* a new lookup.
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*/
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d_drop(dentry);
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d_drop(sdentry);
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}
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iput(&vnode->vfs_inode);
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dput(sdentry);
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out:
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* Tell the server to remove a sillyrename file.
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*/
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static int afs_do_silly_unlink(struct afs_vnode *dvnode, struct afs_vnode *vnode,
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struct dentry *dentry, struct key *key)
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{
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struct afs_fs_cursor fc;
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struct afs_status_cb *scb;
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int ret = -ERESTARTSYS;
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_enter("");
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scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
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if (!scb)
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return -ENOMEM;
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trace_afs_silly_rename(vnode, true);
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if (afs_begin_vnode_operation(&fc, dvnode, key, false)) {
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afs_dataversion_t dir_data_version = dvnode->status.data_version + 1;
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while (afs_select_fileserver(&fc)) {
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fc.cb_break = afs_calc_vnode_cb_break(dvnode);
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if (test_bit(AFS_SERVER_FL_IS_YFS, &fc.cbi->server->flags) &&
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!test_bit(AFS_SERVER_FL_NO_RM2, &fc.cbi->server->flags)) {
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yfs_fs_remove_file2(&fc, vnode, dentry->d_name.name,
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&scb[0], &scb[1]);
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if (fc.ac.error != -ECONNABORTED ||
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fc.ac.abort_code != RXGEN_OPCODE)
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continue;
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set_bit(AFS_SERVER_FL_NO_RM2, &fc.cbi->server->flags);
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}
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afs_fs_remove(&fc, vnode, dentry->d_name.name, false, &scb[0]);
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}
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afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
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&dir_data_version, &scb[0]);
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ret = afs_end_vnode_operation(&fc);
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if (ret == 0) {
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drop_nlink(&vnode->vfs_inode);
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if (vnode->vfs_inode.i_nlink == 0) {
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set_bit(AFS_VNODE_DELETED, &vnode->flags);
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clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
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}
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}
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if (ret == 0 &&
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test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
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afs_edit_dir_remove(dvnode, &dentry->d_name,
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afs_edit_dir_for_unlink);
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}
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kfree(scb);
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* Remove sillyrename file on iput.
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*/
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int afs_silly_iput(struct dentry *dentry, struct inode *inode)
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{
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struct afs_vnode *dvnode = AFS_FS_I(d_inode(dentry->d_parent));
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct dentry *alias;
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int ret;
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DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
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_enter("%p{%pd},%llx", dentry, dentry, vnode->fid.vnode);
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down_read(&dvnode->rmdir_lock);
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alias = d_alloc_parallel(dentry->d_parent, &dentry->d_name, &wq);
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if (IS_ERR(alias)) {
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up_read(&dvnode->rmdir_lock);
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return 0;
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}
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if (!d_in_lookup(alias)) {
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/* We raced with lookup... See if we need to transfer the
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* sillyrename information to the aliased dentry.
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*/
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ret = 0;
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spin_lock(&alias->d_lock);
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if (d_really_is_positive(alias) &&
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!(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
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alias->d_flags |= DCACHE_NFSFS_RENAMED;
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ret = 1;
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}
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spin_unlock(&alias->d_lock);
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up_read(&dvnode->rmdir_lock);
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dput(alias);
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return ret;
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}
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/* Stop lock-release from complaining. */
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spin_lock(&vnode->lock);
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vnode->lock_state = AFS_VNODE_LOCK_DELETED;
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trace_afs_flock_ev(vnode, NULL, afs_flock_silly_delete, 0);
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spin_unlock(&vnode->lock);
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afs_do_silly_unlink(dvnode, vnode, dentry, dvnode->silly_key);
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up_read(&dvnode->rmdir_lock);
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d_lookup_done(alias);
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dput(alias);
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return 1;
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}
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