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fscache: Procfile to display cookies

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Add /proc/fs/fscache/cookies to display active cookies.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/158861211871.340223.7223853943667440807.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/159465771021.1376105.6933857529128238020.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/160588460994.3465195.16963417803501149328.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/162431194785.2908479.786917990782538164.stgit@warthog.procyon.org.uk/
This commit is contained in:
David Howells 2020-02-10 10:00:22 +00:00
parent 2908f5e101
commit 884a76881f
4 changed files with 112 additions and 0 deletions
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103
fs/fscache/cookie.c
View File

@ -19,6 +19,8 @@ static atomic_t fscache_object_debug_id = ATOMIC_INIT(0);
#define fscache_cookie_hash_shift 15
static struct hlist_bl_head fscache_cookie_hash[1 << fscache_cookie_hash_shift];
static LIST_HEAD(fscache_cookies);
static DEFINE_RWLOCK(fscache_cookies_lock);
static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie,
loff_t object_size);
@ -65,6 +67,9 @@ void fscache_free_cookie(struct fscache_cookie *cookie)
{
if (cookie) {
BUG_ON(!hlist_empty(&cookie->backing_objects));
write_lock(&fscache_cookies_lock);
list_del(&cookie->proc_link);
write_unlock(&fscache_cookies_lock);
if (cookie->aux_len > sizeof(cookie->inline_aux))
kfree(cookie->aux);
if (cookie->key_len > sizeof(cookie->inline_key))
@ -192,6 +197,10 @@ struct fscache_cookie *fscache_alloc_cookie(
/* radix tree insertion won't use the preallocation pool unless it's
* told it may not wait */
INIT_RADIX_TREE(&cookie->stores, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
write_lock(&fscache_cookies_lock);
list_add_tail(&cookie->proc_link, &fscache_cookies);
write_unlock(&fscache_cookies_lock);
return cookie;
nomem:
@ -969,3 +978,97 @@ inconsistent:
return -ESTALE;
}
EXPORT_SYMBOL(__fscache_check_consistency);
/*
* Generate a list of extant cookies in /proc/fs/fscache/cookies
*/
static int fscache_cookies_seq_show(struct seq_file *m, void *v)
{
struct fscache_cookie *cookie;
unsigned int keylen = 0, auxlen = 0;
char _type[3], *type;
u8 *p;
if (v == &fscache_cookies) {
seq_puts(m,
"COOKIE PARENT USAGE CHILD ACT TY FL DEF NETFS_DATA\n"
"======== ======== ===== ===== === == === ================ ==========\n"
);
return 0;
}
cookie = list_entry(v, struct fscache_cookie, proc_link);
switch (cookie->type) {
case 0:
type = "IX";
break;
case 1:
type = "DT";
break;
default:
snprintf(_type, sizeof(_type), "%02u",
cookie->type);
type = _type;
break;
}
seq_printf(m,
"%08x %08x %5u %5u %3u %s %03lx %-16s %px",
cookie->debug_id,
cookie->parent ? cookie->parent->debug_id : 0,
atomic_read(&cookie->usage),
atomic_read(&cookie->n_children),
atomic_read(&cookie->n_active),
type,
cookie->flags,
cookie->def->name,
cookie->netfs_data);
keylen = cookie->key_len;
auxlen = cookie->aux_len;
if (keylen > 0 || auxlen > 0) {
seq_puts(m, " ");
p = keylen <= sizeof(cookie->inline_key) ?
cookie->inline_key : cookie->key;
for (; keylen > 0; keylen--)
seq_printf(m, "%02x", *p++);
if (auxlen > 0) {
seq_puts(m, ", ");
p = auxlen <= sizeof(cookie->inline_aux) ?
cookie->inline_aux : cookie->aux;
for (; auxlen > 0; auxlen--)
seq_printf(m, "%02x", *p++);
}
}
seq_puts(m, "\n");
return 0;
}
static void *fscache_cookies_seq_start(struct seq_file *m, loff_t *_pos)
__acquires(fscache_cookies_lock)
{
read_lock(&fscache_cookies_lock);
return seq_list_start_head(&fscache_cookies, *_pos);
}
static void *fscache_cookies_seq_next(struct seq_file *m, void *v, loff_t *_pos)
{
return seq_list_next(v, &fscache_cookies, _pos);
}
static void fscache_cookies_seq_stop(struct seq_file *m, void *v)
__releases(rcu)
{
read_unlock(&fscache_cookies_lock);
}
const struct seq_operations fscache_cookies_seq_ops = {
.start = fscache_cookies_seq_start,
.next = fscache_cookies_seq_next,
.stop = fscache_cookies_seq_stop,
.show = fscache_cookies_seq_show,
};

1
fs/fscache/internal.h
View File

@ -45,6 +45,7 @@ extern struct fscache_cache *fscache_select_cache_for_object(
* cookie.c
*/
extern struct kmem_cache *fscache_cookie_jar;
extern const struct seq_operations fscache_cookies_seq_ops;
extern void fscache_free_cookie(struct fscache_cookie *);
extern struct fscache_cookie *fscache_alloc_cookie(struct fscache_cookie *,

7
fs/fscache/proc.c
View File

@ -21,6 +21,10 @@ int __init fscache_proc_init(void)
if (!proc_mkdir("fs/fscache", NULL))
goto error_dir;
if (!proc_create_seq("fs/fscache/cookies", S_IFREG | 0444, NULL,
&fscache_cookies_seq_ops))
goto error_cookies;
#ifdef CONFIG_FSCACHE_STATS
if (!proc_create_single("fs/fscache/stats", S_IFREG | 0444, NULL,
fscache_stats_show))
@ -53,6 +57,8 @@ error_histogram:
remove_proc_entry("fs/fscache/stats", NULL);
error_stats:
#endif
remove_proc_entry("fs/fscache/cookies", NULL);
error_cookies:
remove_proc_entry("fs/fscache", NULL);
error_dir:
_leave(" = -ENOMEM");
@ -73,5 +79,6 @@ void fscache_proc_cleanup(void)
#ifdef CONFIG_FSCACHE_STATS
remove_proc_entry("fs/fscache/stats", NULL);
#endif
remove_proc_entry("fs/fscache/cookies", NULL);
remove_proc_entry("fs/fscache", NULL);
}

1
include/linux/fscache.h
View File

@ -133,6 +133,7 @@ struct fscache_cookie {
const struct fscache_cookie_def *def; /* definition */
struct fscache_cookie *parent; /* parent of this entry */
struct hlist_bl_node hash_link; /* Link in hash table */
struct list_head proc_link; /* Link in proc list */
void *netfs_data; /* back pointer to netfs */
struct radix_tree_root stores; /* pages to be stored on this cookie */
#define FSCACHE_COOKIE_PENDING_TAG 0 /* pages tag: pending write to cache */