2874c5fd28
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 license as published by the free software foundation either version 2 of the license 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 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
98 lines
2.9 KiB
C
98 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* Filesystem index definition
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*
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* Copyright (C) 2004-2007 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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#define FSCACHE_DEBUG_LEVEL CACHE
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#include <linux/module.h>
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#include "internal.h"
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static
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enum fscache_checkaux fscache_fsdef_netfs_check_aux(void *cookie_netfs_data,
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const void *data,
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uint16_t datalen,
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loff_t object_size);
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/*
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* The root index is owned by FS-Cache itself.
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*
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* When a netfs requests caching facilities, FS-Cache will, if one doesn't
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* already exist, create an entry in the root index with the key being the name
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* of the netfs ("AFS" for example), and the auxiliary data holding the index
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* structure version supplied by the netfs:
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*
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* FSDEF
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* |
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* +-----------+
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* | |
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* NFS AFS
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* [v=1] [v=1]
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*
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* If an entry with the appropriate name does already exist, the version is
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* compared. If the version is different, the entire subtree from that entry
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* will be discarded and a new entry created.
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*
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* The new entry will be an index, and a cookie referring to it will be passed
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* to the netfs. This is then the root handle by which the netfs accesses the
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* cache. It can create whatever objects it likes in that index, including
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* further indices.
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*/
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static struct fscache_cookie_def fscache_fsdef_index_def = {
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.name = ".FS-Cache",
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.type = FSCACHE_COOKIE_TYPE_INDEX,
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};
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struct fscache_cookie fscache_fsdef_index = {
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.usage = ATOMIC_INIT(1),
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.n_active = ATOMIC_INIT(1),
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.lock = __SPIN_LOCK_UNLOCKED(fscache_fsdef_index.lock),
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.backing_objects = HLIST_HEAD_INIT,
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.def = &fscache_fsdef_index_def,
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.flags = 1 << FSCACHE_COOKIE_ENABLED,
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.type = FSCACHE_COOKIE_TYPE_INDEX,
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};
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EXPORT_SYMBOL(fscache_fsdef_index);
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/*
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* Definition of an entry in the root index. Each entry is an index, keyed to
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* a specific netfs and only applicable to a particular version of the index
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* structure used by that netfs.
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*/
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struct fscache_cookie_def fscache_fsdef_netfs_def = {
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.name = "FSDEF.netfs",
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.type = FSCACHE_COOKIE_TYPE_INDEX,
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.check_aux = fscache_fsdef_netfs_check_aux,
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};
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/*
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* check that the index structure version number stored in the auxiliary data
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* matches the one the netfs gave us
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*/
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static enum fscache_checkaux fscache_fsdef_netfs_check_aux(
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void *cookie_netfs_data,
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const void *data,
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uint16_t datalen,
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loff_t object_size)
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{
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struct fscache_netfs *netfs = cookie_netfs_data;
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uint32_t version;
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_enter("{%s},,%hu", netfs->name, datalen);
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if (datalen != sizeof(version)) {
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_leave(" = OBSOLETE [dl=%d v=%zu]", datalen, sizeof(version));
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return FSCACHE_CHECKAUX_OBSOLETE;
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}
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memcpy(&version, data, sizeof(version));
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if (version != netfs->version) {
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_leave(" = OBSOLETE [ver=%x net=%x]", version, netfs->version);
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return FSCACHE_CHECKAUX_OBSOLETE;
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}
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_leave(" = OKAY");
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return FSCACHE_CHECKAUX_OKAY;
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}
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