forked from Minki/linux
2fba46a04c
Before this patch, multiple users called gfs2_qa_alloc which allocated a qadata structure to the inode, if quotas are turned on. Later, in file close or evict, the structure was deleted with gfs2_qa_delete. But there can be several competing processes who need access to the structure. There were races between file close (release) and the others. Thus, a release could delete the structure out from under a process that relied upon its existence. For example, chown. This patch changes the management of the qadata structures to be a get/put scheme. Function gfs2_qa_alloc has been changed to gfs2_qa_get and if the structure is allocated, the count essentially starts out at 1. Function gfs2_qa_delete has been renamed to gfs2_qa_put, and the last guy to decrement the count to 0 frees the memory. Signed-off-by: Bob Peterson <rpeterso@redhat.com>
151 lines
3.1 KiB
C
151 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*/
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/completion.h>
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#include <linux/buffer_head.h>
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#include <linux/xattr.h>
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#include <linux/posix_acl.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/gfs2_ondisk.h>
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#include "gfs2.h"
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#include "incore.h"
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#include "acl.h"
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#include "xattr.h"
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#include "glock.h"
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#include "inode.h"
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#include "meta_io.h"
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#include "quota.h"
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#include "rgrp.h"
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#include "trans.h"
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#include "util.h"
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static const char *gfs2_acl_name(int type)
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{
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switch (type) {
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case ACL_TYPE_ACCESS:
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return XATTR_POSIX_ACL_ACCESS;
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case ACL_TYPE_DEFAULT:
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return XATTR_POSIX_ACL_DEFAULT;
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}
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return NULL;
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}
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static struct posix_acl *__gfs2_get_acl(struct inode *inode, int type)
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{
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struct gfs2_inode *ip = GFS2_I(inode);
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struct posix_acl *acl;
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const char *name;
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char *data;
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int len;
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if (!ip->i_eattr)
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return NULL;
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name = gfs2_acl_name(type);
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len = gfs2_xattr_acl_get(ip, name, &data);
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if (len <= 0)
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return ERR_PTR(len);
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acl = posix_acl_from_xattr(&init_user_ns, data, len);
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kfree(data);
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return acl;
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}
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struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
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{
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struct gfs2_inode *ip = GFS2_I(inode);
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struct gfs2_holder gh;
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bool need_unlock = false;
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struct posix_acl *acl;
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if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
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int ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
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LM_FLAG_ANY, &gh);
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if (ret)
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return ERR_PTR(ret);
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need_unlock = true;
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}
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acl = __gfs2_get_acl(inode, type);
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if (need_unlock)
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gfs2_glock_dq_uninit(&gh);
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return acl;
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}
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int __gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
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{
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int error;
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size_t len;
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char *data;
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const char *name = gfs2_acl_name(type);
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if (acl) {
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len = posix_acl_xattr_size(acl->a_count);
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data = kmalloc(len, GFP_NOFS);
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if (data == NULL)
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return -ENOMEM;
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error = posix_acl_to_xattr(&init_user_ns, acl, data, len);
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if (error < 0)
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goto out;
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} else {
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data = NULL;
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len = 0;
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}
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error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
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if (error)
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goto out;
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set_cached_acl(inode, type, acl);
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out:
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kfree(data);
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return error;
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}
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int gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
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{
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struct gfs2_inode *ip = GFS2_I(inode);
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struct gfs2_holder gh;
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bool need_unlock = false;
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int ret;
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umode_t mode;
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if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
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return -E2BIG;
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ret = gfs2_qa_get(ip);
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if (ret)
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return ret;
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if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
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ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
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if (ret)
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goto out;
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need_unlock = true;
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}
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mode = inode->i_mode;
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if (type == ACL_TYPE_ACCESS && acl) {
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ret = posix_acl_update_mode(inode, &mode, &acl);
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if (ret)
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goto unlock;
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}
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ret = __gfs2_set_acl(inode, acl, type);
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if (!ret && mode != inode->i_mode) {
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inode->i_ctime = current_time(inode);
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inode->i_mode = mode;
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mark_inode_dirty(inode);
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}
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unlock:
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if (need_unlock)
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gfs2_glock_dq_uninit(&gh);
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out:
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gfs2_qa_put(ip);
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return ret;
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}
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