1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* 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 fanout |
15 | * directories are created and pinned. |
16 | */ |
17 | void 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(size: sizeof(struct cachefiles_volume), GFP_KERNEL); |
31 | if (!volume) |
32 | return; |
33 | volume->vcookie = vcookie; |
34 | volume->cache = cache; |
35 | INIT_LIST_HEAD(list: &volume->cache_link); |
36 | |
37 | cachefiles_begin_secure(cache, saved_cred: &saved_cred); |
38 | |
39 | len = vcookie->key[0]; |
40 | name = kmalloc(size: 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 | |
47 | retry: |
48 | vdentry = cachefiles_get_directory(cache, dir: cache->store, name, is_new: &is_new); |
49 | if (IS_ERR(ptr: 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(inode: d_inode(dentry: cache->store), subclass: I_MUTEX_PARENT); |
62 | cachefiles_bury_object(cache, NULL, dir: cache->store, rep: vdentry, |
63 | why: FSCACHE_VOLUME_IS_WEIRD); |
64 | cachefiles_put_directory(dir: volume->dentry); |
65 | cond_resched(); |
66 | goto retry; |
67 | } |
68 | } |
69 | |
70 | for (i = 0; i < 256; i++) { |
71 | sprintf(buf: name, fmt: "@%02x" , i); |
72 | fan = cachefiles_get_directory(cache, dir: vdentry, name, NULL); |
73 | if (IS_ERR(ptr: 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(v: &vcookie->n_accesses); /* Stop wakeups on dec-to-0 */ |
82 | trace_fscache_access_volume(volume_debug_id: vcookie->debug_id, cookie_debug_id: 0, |
83 | ref: refcount_read(r: &vcookie->ref), |
84 | n_accesses, why: fscache_access_cache_pin); |
85 | |
86 | spin_lock(lock: &cache->object_list_lock); |
87 | list_add(new: &volume->cache_link, head: &volume->cache->volumes); |
88 | spin_unlock(lock: &cache->object_list_lock); |
89 | |
90 | kfree(objp: name); |
91 | return; |
92 | |
93 | error_fan: |
94 | for (i = 0; i < 256; i++) |
95 | cachefiles_put_directory(dir: volume->fanout[i]); |
96 | error_dir: |
97 | cachefiles_put_directory(dir: volume->dentry); |
98 | error_name: |
99 | kfree(objp: name); |
100 | error_vol: |
101 | kfree(objp: volume); |
102 | cachefiles_end_secure(cache, saved_cred); |
103 | } |
104 | |
105 | /* |
106 | * Release a volume representation. |
107 | */ |
108 | static 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(dir: volume->fanout[i]); |
118 | cachefiles_put_directory(dir: volume->dentry); |
119 | kfree(objp: volume); |
120 | } |
121 | |
122 | void cachefiles_free_volume(struct fscache_volume *vcookie) |
123 | { |
124 | struct cachefiles_volume *volume = vcookie->cache_priv; |
125 | |
126 | if (volume) { |
127 | spin_lock(lock: &volume->cache->object_list_lock); |
128 | list_del_init(entry: &volume->cache_link); |
129 | spin_unlock(lock: &volume->cache->object_list_lock); |
130 | __cachefiles_free_volume(volume); |
131 | } |
132 | } |
133 | |
134 | void cachefiles_withdraw_volume(struct cachefiles_volume *volume) |
135 | { |
136 | fscache_withdraw_volume(volume: volume->vcookie); |
137 | cachefiles_set_volume_xattr(volume); |
138 | __cachefiles_free_volume(volume); |
139 | } |
140 | |