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1// SPDX-License-Identifier: GPL-2.0-or-later2/* Volume handling.3 *4 * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.5 * Written by David Howells (dhowells@redhat.com)6 */7 8#include <linux/fs.h>9#include <linux/slab.h>10#include "internal.h"11#include <trace/events/fscache.h>12 13/*14 * Allocate and set up a volume representation. We make sure all the fanout15 * directories are created and pinned.16 */17void cachefiles_acquire_volume(struct fscache_volume *vcookie)18{19 struct cachefiles_volume *volume;20 struct cachefiles_cache *cache = vcookie->cache->cache_priv;21 const struct cred *saved_cred;22 struct dentry *vdentry, *fan;23 size_t len;24 char *name;25 bool is_new = false;26 int ret, n_accesses, i;27 28 _enter("");29 30 volume = kzalloc(sizeof(struct cachefiles_volume), GFP_KERNEL);31 if (!volume)32 return;33 volume->vcookie = vcookie;34 volume->cache = cache;35 INIT_LIST_HEAD(&volume->cache_link);36 37 cachefiles_begin_secure(cache, &saved_cred);38 39 len = vcookie->key[0];40 name = kmalloc(len + 3, GFP_NOFS);41 if (!name)42 goto error_vol;43 name[0] = 'I';44 memcpy(name + 1, vcookie->key + 1, len);45 name[len + 1] = 0;46 47retry:48 vdentry = cachefiles_get_directory(cache, cache->store, name, &is_new);49 if (IS_ERR(vdentry))50 goto error_name;51 volume->dentry = vdentry;52 53 if (is_new) {54 if (!cachefiles_set_volume_xattr(volume))55 goto error_dir;56 } else {57 ret = cachefiles_check_volume_xattr(volume);58 if (ret < 0) {59 if (ret != -ESTALE)60 goto error_dir;61 inode_lock_nested(d_inode(cache->store), I_MUTEX_PARENT);62 cachefiles_bury_object(cache, NULL, cache->store, vdentry,63 FSCACHE_VOLUME_IS_WEIRD);64 cachefiles_put_directory(volume->dentry);65 cond_resched();66 goto retry;67 }68 }69 70 for (i = 0; i < 256; i++) {71 sprintf(name, "@%02x", i);72 fan = cachefiles_get_directory(cache, vdentry, name, NULL);73 if (IS_ERR(fan))74 goto error_fan;75 volume->fanout[i] = fan;76 }77 78 cachefiles_end_secure(cache, saved_cred);79 80 vcookie->cache_priv = volume;81 n_accesses = atomic_inc_return(&vcookie->n_accesses); /* Stop wakeups on dec-to-0 */82 trace_fscache_access_volume(vcookie->debug_id, 0,83 refcount_read(&vcookie->ref),84 n_accesses, fscache_access_cache_pin);85 86 spin_lock(&cache->object_list_lock);87 list_add(&volume->cache_link, &volume->cache->volumes);88 spin_unlock(&cache->object_list_lock);89 90 kfree(name);91 return;92 93error_fan:94 for (i = 0; i < 256; i++)95 cachefiles_put_directory(volume->fanout[i]);96error_dir:97 cachefiles_put_directory(volume->dentry);98error_name:99 kfree(name);100error_vol:101 kfree(volume);102 cachefiles_end_secure(cache, saved_cred);103}104 105/*106 * Release a volume representation.107 */108static void __cachefiles_free_volume(struct cachefiles_volume *volume)109{110 int i;111 112 _enter("");113 114 volume->vcookie->cache_priv = NULL;115 116 for (i = 0; i < 256; i++)117 cachefiles_put_directory(volume->fanout[i]);118 cachefiles_put_directory(volume->dentry);119 kfree(volume);120}121 122void cachefiles_free_volume(struct fscache_volume *vcookie)123{124 struct cachefiles_volume *volume = vcookie->cache_priv;125 126 if (volume) {127 spin_lock(&volume->cache->object_list_lock);128 list_del_init(&volume->cache_link);129 spin_unlock(&volume->cache->object_list_lock);130 __cachefiles_free_volume(volume);131 }132}133 134void cachefiles_withdraw_volume(struct cachefiles_volume *volume)135{136 cachefiles_set_volume_xattr(volume);137 __cachefiles_free_volume(volume);138}139