364 lines
8.4 KiB
C
364 lines
8.4 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/* Extended attribute handling for AFS. We use xattrs to get and set metadata
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* instead of providing pioctl().
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*
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* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/xattr.h>
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#include "internal.h"
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/*
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* Deal with the result of a successful fetch ACL operation.
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*/
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static void afs_acl_success(struct afs_operation *op)
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{
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afs_vnode_commit_status(op, &op->file[0]);
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}
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static void afs_acl_put(struct afs_operation *op)
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{
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kfree(op->acl);
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}
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static const struct afs_operation_ops afs_fetch_acl_operation = {
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.issue_afs_rpc = afs_fs_fetch_acl,
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.success = afs_acl_success,
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.put = afs_acl_put,
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};
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/*
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* Get a file's ACL.
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*/
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static int afs_xattr_get_acl(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_operation *op;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct afs_acl *acl = NULL;
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int ret;
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op = afs_alloc_operation(NULL, vnode->volume);
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if (IS_ERR(op))
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return -ENOMEM;
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afs_op_set_vnode(op, 0, vnode);
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op->ops = &afs_fetch_acl_operation;
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afs_begin_vnode_operation(op);
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afs_wait_for_operation(op);
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acl = op->acl;
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op->acl = NULL;
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ret = afs_put_operation(op);
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if (ret == 0) {
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ret = acl->size;
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if (size > 0) {
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if (acl->size <= size)
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memcpy(buffer, acl->data, acl->size);
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else
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ret = -ERANGE;
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}
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}
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kfree(acl);
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return ret;
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}
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static bool afs_make_acl(struct afs_operation *op,
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const void *buffer, size_t size)
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{
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struct afs_acl *acl;
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acl = kmalloc(sizeof(*acl) + size, GFP_KERNEL);
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if (!acl) {
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afs_op_nomem(op);
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return false;
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}
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acl->size = size;
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memcpy(acl->data, buffer, size);
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op->acl = acl;
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return true;
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}
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static const struct afs_operation_ops afs_store_acl_operation = {
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.issue_afs_rpc = afs_fs_store_acl,
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.success = afs_acl_success,
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.put = afs_acl_put,
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};
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/*
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* Set a file's AFS3 ACL.
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*/
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static int afs_xattr_set_acl(const struct xattr_handler *handler,
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struct user_namespace *mnt_userns,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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const void *buffer, size_t size, int flags)
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{
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struct afs_operation *op;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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if (flags == XATTR_CREATE)
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return -EINVAL;
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op = afs_alloc_operation(NULL, vnode->volume);
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if (IS_ERR(op))
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return -ENOMEM;
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afs_op_set_vnode(op, 0, vnode);
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if (!afs_make_acl(op, buffer, size))
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return afs_put_operation(op);
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op->ops = &afs_store_acl_operation;
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return afs_do_sync_operation(op);
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}
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static const struct xattr_handler afs_xattr_afs_acl_handler = {
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.name = "afs.acl",
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.get = afs_xattr_get_acl,
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.set = afs_xattr_set_acl,
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};
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static const struct afs_operation_ops yfs_fetch_opaque_acl_operation = {
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.issue_yfs_rpc = yfs_fs_fetch_opaque_acl,
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.success = afs_acl_success,
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/* Don't free op->yacl in .put here */
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};
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/*
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* Get a file's YFS ACL.
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*/
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static int afs_xattr_get_yfs(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_operation *op;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct yfs_acl *yacl = NULL;
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char buf[16], *data;
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int which = 0, dsize, ret = -ENOMEM;
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if (strcmp(name, "acl") == 0)
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which = 0;
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else if (strcmp(name, "acl_inherited") == 0)
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which = 1;
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else if (strcmp(name, "acl_num_cleaned") == 0)
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which = 2;
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else if (strcmp(name, "vol_acl") == 0)
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which = 3;
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else
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return -EOPNOTSUPP;
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yacl = kzalloc(sizeof(struct yfs_acl), GFP_KERNEL);
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if (!yacl)
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goto error;
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if (which == 0)
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yacl->flags |= YFS_ACL_WANT_ACL;
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else if (which == 3)
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yacl->flags |= YFS_ACL_WANT_VOL_ACL;
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op = afs_alloc_operation(NULL, vnode->volume);
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if (IS_ERR(op))
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goto error_yacl;
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afs_op_set_vnode(op, 0, vnode);
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op->yacl = yacl;
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op->ops = &yfs_fetch_opaque_acl_operation;
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afs_begin_vnode_operation(op);
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afs_wait_for_operation(op);
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ret = afs_put_operation(op);
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if (ret == 0) {
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switch (which) {
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case 0:
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data = yacl->acl->data;
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dsize = yacl->acl->size;
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break;
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case 1:
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data = buf;
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dsize = scnprintf(buf, sizeof(buf), "%u", yacl->inherit_flag);
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break;
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case 2:
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data = buf;
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dsize = scnprintf(buf, sizeof(buf), "%u", yacl->num_cleaned);
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break;
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case 3:
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data = yacl->vol_acl->data;
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dsize = yacl->vol_acl->size;
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break;
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default:
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ret = -EOPNOTSUPP;
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goto error_yacl;
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}
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ret = dsize;
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if (size > 0) {
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if (dsize <= size)
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memcpy(buffer, data, dsize);
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else
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ret = -ERANGE;
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}
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} else if (ret == -ENOTSUPP) {
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ret = -ENODATA;
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}
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error_yacl:
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yfs_free_opaque_acl(yacl);
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error:
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return ret;
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}
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static const struct afs_operation_ops yfs_store_opaque_acl2_operation = {
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.issue_yfs_rpc = yfs_fs_store_opaque_acl2,
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.success = afs_acl_success,
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.put = afs_acl_put,
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};
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/*
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* Set a file's YFS ACL.
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*/
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static int afs_xattr_set_yfs(const struct xattr_handler *handler,
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struct user_namespace *mnt_userns,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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const void *buffer, size_t size, int flags)
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{
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struct afs_operation *op;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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int ret;
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if (flags == XATTR_CREATE ||
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strcmp(name, "acl") != 0)
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return -EINVAL;
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op = afs_alloc_operation(NULL, vnode->volume);
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if (IS_ERR(op))
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return -ENOMEM;
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afs_op_set_vnode(op, 0, vnode);
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if (!afs_make_acl(op, buffer, size))
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return afs_put_operation(op);
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op->ops = &yfs_store_opaque_acl2_operation;
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ret = afs_do_sync_operation(op);
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if (ret == -ENOTSUPP)
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ret = -ENODATA;
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return ret;
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}
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static const struct xattr_handler afs_xattr_yfs_handler = {
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.prefix = "afs.yfs.",
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.get = afs_xattr_get_yfs,
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.set = afs_xattr_set_yfs,
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};
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/*
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* Get the name of the cell on which a file resides.
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*/
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static int afs_xattr_get_cell(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct afs_cell *cell = vnode->volume->cell;
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size_t namelen;
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namelen = cell->name_len;
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if (size == 0)
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return namelen;
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if (namelen > size)
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return -ERANGE;
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memcpy(buffer, cell->name, namelen);
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return namelen;
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}
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static const struct xattr_handler afs_xattr_afs_cell_handler = {
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.name = "afs.cell",
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.get = afs_xattr_get_cell,
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};
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/*
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* Get the volume ID, vnode ID and vnode uniquifier of a file as a sequence of
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* hex numbers separated by colons.
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*/
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static int afs_xattr_get_fid(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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char text[16 + 1 + 24 + 1 + 8 + 1];
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size_t len;
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/* The volume ID is 64-bit, the vnode ID is 96-bit and the
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* uniquifier is 32-bit.
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*/
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len = scnprintf(text, sizeof(text), "%llx:", vnode->fid.vid);
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if (vnode->fid.vnode_hi)
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len += scnprintf(text + len, sizeof(text) - len, "%x%016llx",
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vnode->fid.vnode_hi, vnode->fid.vnode);
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else
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len += scnprintf(text + len, sizeof(text) - len, "%llx",
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vnode->fid.vnode);
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len += scnprintf(text + len, sizeof(text) - len, ":%x",
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vnode->fid.unique);
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if (size == 0)
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return len;
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if (len > size)
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return -ERANGE;
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memcpy(buffer, text, len);
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return len;
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}
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static const struct xattr_handler afs_xattr_afs_fid_handler = {
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.name = "afs.fid",
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.get = afs_xattr_get_fid,
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};
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/*
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* Get the name of the volume on which a file resides.
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*/
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static int afs_xattr_get_volume(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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const char *volname = vnode->volume->name;
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size_t namelen;
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namelen = strlen(volname);
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if (size == 0)
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return namelen;
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if (namelen > size)
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return -ERANGE;
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memcpy(buffer, volname, namelen);
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return namelen;
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}
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static const struct xattr_handler afs_xattr_afs_volume_handler = {
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.name = "afs.volume",
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.get = afs_xattr_get_volume,
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};
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const struct xattr_handler *afs_xattr_handlers[] = {
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&afs_xattr_afs_acl_handler,
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&afs_xattr_afs_cell_handler,
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&afs_xattr_afs_fid_handler,
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&afs_xattr_afs_volume_handler,
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&afs_xattr_yfs_handler, /* afs.yfs. prefix */
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NULL
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};
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