fs/gfs2/acl.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
0004  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
0005  */
0006
0007 #include <linux/sched.h>
0008 #include <linux/slab.h>
0009 #include <linux/spinlock.h>
0010 #include <linux/completion.h>
0011 #include <linux/buffer_head.h>
0012 #include <linux/xattr.h>
0013 #include <linux/posix_acl.h>
0014 #include <linux/posix_acl_xattr.h>
0015 #include <linux/gfs2_ondisk.h>
0016
0017 #include "gfs2.h"
0018 #include "incore.h"
0019 #include "acl.h"
0020 #include "xattr.h"
0021 #include "glock.h"
0022 #include "inode.h"
0023 #include "meta_io.h"
0024 #include "quota.h"
0025 #include "rgrp.h"
0026 #include "trans.h"
0027 #include "util.h"
0028
0029 static const char *gfs2_acl_name(int type)
0030 {
0031     switch (type) {
0032     case ACL_TYPE_ACCESS:
0033         return XATTR_POSIX_ACL_ACCESS;
0034     case ACL_TYPE_DEFAULT:
0035         return XATTR_POSIX_ACL_DEFAULT;
0036     }
0037     return NULL;
0038 }
0039
0040 static struct posix_acl *__gfs2_get_acl(struct inode *inode, int type)
0041 {
0042     struct gfs2_inode *ip = GFS2_I(inode);
0043     struct posix_acl *acl;
0044     const char *name;
0045     char *data;
0046     int len;
0047
0048     if (!ip->i_eattr)
0049         return NULL;
0050
0051     name = gfs2_acl_name(type);
0052     len = gfs2_xattr_acl_get(ip, name, &data);
0053     if (len <= 0)
0054         return ERR_PTR(len);
0055     acl = posix_acl_from_xattr(&init_user_ns, data, len);
0056     kfree(data);
0057     return acl;
0058 }
0059
0060 struct posix_acl *gfs2_get_acl(struct inode *inode, int type, bool rcu)
0061 {
0062     struct gfs2_inode *ip = GFS2_I(inode);
0063     struct gfs2_holder gh;
0064     bool need_unlock = false;
0065     struct posix_acl *acl;
0066
0067     if (rcu)
0068         return ERR_PTR(-ECHILD);
0069
0070     if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
0071         int ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
0072                          LM_FLAG_ANY, &gh);
0073         if (ret)
0074             return ERR_PTR(ret);
0075         need_unlock = true;
0076     }
0077     acl = __gfs2_get_acl(inode, type);
0078     if (need_unlock)
0079         gfs2_glock_dq_uninit(&gh);
0080     return acl;
0081 }
0082
0083 int __gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
0084 {
0085     int error;
0086     size_t len;
0087     char *data;
0088     const char *name = gfs2_acl_name(type);
0089
0090     if (acl) {
0091         len = posix_acl_xattr_size(acl->a_count);
0092         data = kmalloc(len, GFP_NOFS);
0093         if (data == NULL)
0094             return -ENOMEM;
0095         error = posix_acl_to_xattr(&init_user_ns, acl, data, len);
0096         if (error < 0)
0097             goto out;
0098     } else {
0099         data = NULL;
0100         len = 0;
0101     }
0102
0103     error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
0104     if (error)
0105         goto out;
0106     set_cached_acl(inode, type, acl);
0107 out:
0108     kfree(data);
0109     return error;
0110 }
0111
0112 int gfs2_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
0113          struct posix_acl *acl, int type)
0114 {
0115     struct gfs2_inode *ip = GFS2_I(inode);
0116     struct gfs2_holder gh;
0117     bool need_unlock = false;
0118     int ret;
0119     umode_t mode;
0120
0121     if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
0122         return -E2BIG;
0123
0124     ret = gfs2_qa_get(ip);
0125     if (ret)
0126         return ret;
0127
0128     if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
0129         ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
0130         if (ret)
0131             goto out;
0132         need_unlock = true;
0133     }
0134
0135     mode = inode->i_mode;
0136     if (type == ACL_TYPE_ACCESS && acl) {
0137         ret = posix_acl_update_mode(&init_user_ns, inode, &mode, &acl);
0138         if (ret)
0139             goto unlock;
0140     }
0141
0142     ret = __gfs2_set_acl(inode, acl, type);
0143     if (!ret && mode != inode->i_mode) {
0144         inode->i_ctime = current_time(inode);
0145         inode->i_mode = mode;
0146         mark_inode_dirty(inode);
0147     }
0148 unlock:
0149     if (need_unlock)
0150         gfs2_glock_dq_uninit(&gh);
0151 out:
0152     gfs2_qa_put(ip);
0153     return ret;
0154 }