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295 lines
6.5 KiB
295 lines
6.5 KiB
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/ext4/acl.c
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*
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* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
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*/
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#include <linux/quotaops.h>
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#include "ext4_jbd2.h"
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#include "ext4.h"
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#include "xattr.h"
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#include "acl.h"
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/*
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* Convert from filesystem to in-memory representation.
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*/
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static struct posix_acl *
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ext4_acl_from_disk(const void *value, size_t size)
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{
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const char *end = (char *)value + size;
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int n, count;
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struct posix_acl *acl;
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if (!value)
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return NULL;
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if (size < sizeof(ext4_acl_header))
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return ERR_PTR(-EINVAL);
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if (((ext4_acl_header *)value)->a_version !=
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cpu_to_le32(EXT4_ACL_VERSION))
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return ERR_PTR(-EINVAL);
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value = (char *)value + sizeof(ext4_acl_header);
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count = ext4_acl_count(size);
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if (count < 0)
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return ERR_PTR(-EINVAL);
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if (count == 0)
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return NULL;
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acl = posix_acl_alloc(count, GFP_NOFS);
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if (!acl)
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return ERR_PTR(-ENOMEM);
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for (n = 0; n < count; n++) {
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ext4_acl_entry *entry =
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(ext4_acl_entry *)value;
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if ((char *)value + sizeof(ext4_acl_entry_short) > end)
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goto fail;
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acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
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acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
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switch (acl->a_entries[n].e_tag) {
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case ACL_USER_OBJ:
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case ACL_GROUP_OBJ:
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case ACL_MASK:
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case ACL_OTHER:
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value = (char *)value +
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sizeof(ext4_acl_entry_short);
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break;
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case ACL_USER:
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value = (char *)value + sizeof(ext4_acl_entry);
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if ((char *)value > end)
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goto fail;
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acl->a_entries[n].e_uid =
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make_kuid(&init_user_ns,
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le32_to_cpu(entry->e_id));
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break;
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case ACL_GROUP:
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value = (char *)value + sizeof(ext4_acl_entry);
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if ((char *)value > end)
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goto fail;
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acl->a_entries[n].e_gid =
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make_kgid(&init_user_ns,
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le32_to_cpu(entry->e_id));
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break;
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default:
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goto fail;
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}
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}
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if (value != end)
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goto fail;
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return acl;
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fail:
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posix_acl_release(acl);
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return ERR_PTR(-EINVAL);
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}
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/*
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* Convert from in-memory to filesystem representation.
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*/
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static void *
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ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
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{
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ext4_acl_header *ext_acl;
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char *e;
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size_t n;
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*size = ext4_acl_size(acl->a_count);
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ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
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sizeof(ext4_acl_entry), GFP_NOFS);
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if (!ext_acl)
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return ERR_PTR(-ENOMEM);
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ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
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e = (char *)ext_acl + sizeof(ext4_acl_header);
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for (n = 0; n < acl->a_count; n++) {
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const struct posix_acl_entry *acl_e = &acl->a_entries[n];
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ext4_acl_entry *entry = (ext4_acl_entry *)e;
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entry->e_tag = cpu_to_le16(acl_e->e_tag);
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entry->e_perm = cpu_to_le16(acl_e->e_perm);
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switch (acl_e->e_tag) {
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case ACL_USER:
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entry->e_id = cpu_to_le32(
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from_kuid(&init_user_ns, acl_e->e_uid));
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e += sizeof(ext4_acl_entry);
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break;
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case ACL_GROUP:
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entry->e_id = cpu_to_le32(
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from_kgid(&init_user_ns, acl_e->e_gid));
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e += sizeof(ext4_acl_entry);
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break;
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case ACL_USER_OBJ:
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case ACL_GROUP_OBJ:
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case ACL_MASK:
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case ACL_OTHER:
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e += sizeof(ext4_acl_entry_short);
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break;
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default:
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goto fail;
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}
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}
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return (char *)ext_acl;
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fail:
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kfree(ext_acl);
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return ERR_PTR(-EINVAL);
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}
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/*
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* Inode operation get_posix_acl().
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*
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* inode->i_mutex: don't care
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*/
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struct posix_acl *
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ext4_get_acl(struct inode *inode, int type)
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{
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int name_index;
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char *value = NULL;
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struct posix_acl *acl;
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int retval;
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switch (type) {
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case ACL_TYPE_ACCESS:
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name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
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break;
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default:
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BUG();
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}
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retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
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if (retval > 0) {
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value = kmalloc(retval, GFP_NOFS);
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if (!value)
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return ERR_PTR(-ENOMEM);
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retval = ext4_xattr_get(inode, name_index, "", value, retval);
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}
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if (retval > 0)
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acl = ext4_acl_from_disk(value, retval);
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else if (retval == -ENODATA || retval == -ENOSYS)
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acl = NULL;
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else
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acl = ERR_PTR(retval);
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kfree(value);
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return acl;
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}
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/*
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* Set the access or default ACL of an inode.
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*
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* inode->i_mutex: down unless called from ext4_new_inode
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*/
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static int
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__ext4_set_acl(handle_t *handle, struct inode *inode, int type,
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struct posix_acl *acl, int xattr_flags)
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{
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int name_index;
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void *value = NULL;
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size_t size = 0;
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int error;
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switch (type) {
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case ACL_TYPE_ACCESS:
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name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
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if (!S_ISDIR(inode->i_mode))
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return acl ? -EACCES : 0;
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break;
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default:
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return -EINVAL;
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}
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if (acl) {
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value = ext4_acl_to_disk(acl, &size);
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if (IS_ERR(value))
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return (int)PTR_ERR(value);
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}
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error = ext4_xattr_set_handle(handle, inode, name_index, "",
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value, size, xattr_flags);
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kfree(value);
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if (!error) {
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set_cached_acl(inode, type, acl);
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}
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return error;
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}
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int
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ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
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{
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handle_t *handle;
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int error, credits, retries = 0;
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size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
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umode_t mode = inode->i_mode;
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int update_mode = 0;
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error = dquot_initialize(inode);
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if (error)
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return error;
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retry:
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error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */,
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&credits);
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if (error)
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return error;
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handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
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if (IS_ERR(handle))
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return PTR_ERR(handle);
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if ((type == ACL_TYPE_ACCESS) && acl) {
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error = posix_acl_update_mode(inode, &mode, &acl);
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if (error)
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goto out_stop;
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update_mode = 1;
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}
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error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
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if (!error && update_mode) {
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inode->i_mode = mode;
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inode->i_ctime = current_time(inode);
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ext4_mark_inode_dirty(handle, inode);
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}
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out_stop:
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ext4_journal_stop(handle);
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if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
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goto retry;
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return error;
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}
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/*
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* Initialize the ACLs of a new inode. Called from ext4_new_inode.
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*
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* dir->i_mutex: down
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* inode->i_mutex: up (access to inode is still exclusive)
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*/
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int
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ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
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{
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struct posix_acl *default_acl, *acl;
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int error;
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error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
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if (error)
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return error;
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if (default_acl) {
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error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
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default_acl, XATTR_CREATE);
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posix_acl_release(default_acl);
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}
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if (acl) {
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if (!error)
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error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
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acl, XATTR_CREATE);
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posix_acl_release(acl);
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}
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return error;
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}
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