[RFC PATCH 39/61] fscache: Display cache-specific data in /proc/fs/fscache/objects

From: David Howells
Date: Mon May 04 2020 - 13:13:38 EST


Allow the cache to add information in /proc/fs/fscache/objects instead of
displaying cookie key and aux data - which can be seen in the cookies file.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

fs/cachefiles/content-map.c | 41 +++++++++++++++++++++++++++++++++++++++++
fs/cachefiles/interface.c | 1 +
fs/cachefiles/internal.h | 1 +
fs/fscache/object-list.c | 33 +++------------------------------
include/linux/fscache-cache.h | 4 ++++
5 files changed, 50 insertions(+), 30 deletions(-)

diff --git a/fs/cachefiles/content-map.c b/fs/cachefiles/content-map.c
index dea28948f006..02236b24f914 100644
--- a/fs/cachefiles/content-map.c
+++ b/fs/cachefiles/content-map.c
@@ -408,3 +408,44 @@ void cachefiles_save_content_map(struct cachefiles_object *object)

_leave(" = %zd", ret);
}
+
+/*
+ * Display object information in proc.
+ */
+int cachefiles_display_object(struct seq_file *m, struct fscache_object *_object)
+{
+ struct cachefiles_object *object =
+ container_of(_object, struct cachefiles_object, fscache);
+
+ if (object->fscache.cookie->type == FSCACHE_COOKIE_TYPE_INDEX) {
+ if (object->content_info != CACHEFILES_CONTENT_NO_DATA)
+ seq_printf(m, " ???%u???", object->content_info);
+ } else {
+ switch (object->content_info) {
+ case CACHEFILES_CONTENT_NO_DATA:
+ seq_puts(m, " <n>");
+ break;
+ case CACHEFILES_CONTENT_SINGLE:
+ seq_puts(m, " <s>");
+ break;
+ case CACHEFILES_CONTENT_ALL:
+ seq_puts(m, " <a>");
+ break;
+ case CACHEFILES_CONTENT_MAP:
+ read_lock_bh(&object->content_map_lock);
+ if (object->content_map) {
+ seq_printf(m, " %*phN",
+ object->content_map_size,
+ object->content_map);
+ }
+ read_unlock_bh(&object->content_map_lock);
+ break;
+ default:
+ seq_printf(m, " <%u>", object->content_info);
+ break;
+ }
+ }
+
+ seq_putc(m, '\n');
+ return 0;
+}
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index feff39dff0f5..4fcbd788d3b2 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -495,4 +495,5 @@ const struct fscache_cache_ops cachefiles_cache_ops = {
.shape_extent = cachefiles_shape_extent,
.read = cachefiles_read,
.write = cachefiles_write,
+ .display_object = cachefiles_display_object,
};
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 43f8e71136dd..32cb55319a7d 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -133,6 +133,7 @@ extern void cachefiles_expand_content_map(struct cachefiles_object *object, loff
extern void cachefiles_shorten_content_map(struct cachefiles_object *object, loff_t new_size);
extern bool cachefiles_load_content_map(struct cachefiles_object *object);
extern void cachefiles_save_content_map(struct cachefiles_object *object);
+extern int cachefiles_display_object(struct seq_file *m, struct fscache_object *object);

/*
* daemon.c
diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c
index 5777f909d31a..361610e124bd 100644
--- a/fs/fscache/object-list.c
+++ b/fs/fscache/object-list.c
@@ -155,7 +155,6 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
struct fscache_cookie *cookie;
unsigned long config = data->config;
char _type[3], *type;
- u8 *p;

if ((unsigned long) v == 1) {
seq_puts(m, "OBJECT PARENT USE CHLDN OPS FL S"
@@ -201,8 +200,6 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
obj->stage);

if (obj->cookie) {
- uint16_t keylen = 0, auxlen = 0;
-
switch (cookie->type) {
case 0:
type = "IX";
@@ -211,8 +208,7 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
type = "DT";
break;
default:
- snprintf(_type, sizeof(_type), "%02u",
- cookie->type);
+ snprintf(_type, sizeof(_type), "%02x", cookie->type);
type = _type;
break;
}
@@ -223,34 +219,11 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
type,
cookie->stage,
cookie->flags);
-
- if (config & FSCACHE_OBJLIST_CONFIG_KEY)
- keylen = cookie->key_len;
-
- if (config & FSCACHE_OBJLIST_CONFIG_AUX)
- 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) {
- if (config & FSCACHE_OBJLIST_CONFIG_KEY)
- 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");
} else {
seq_puts(m, "<no_netfs>\n");
}
- return 0;
+
+ return obj->cache->ops->display_object(m, obj);
}

static const struct seq_operations fscache_objlist_ops = {
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index 1d235072239d..f82c998917e0 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -19,6 +19,7 @@

#define NR_MAXCACHES BITS_PER_LONG

+struct seq_file;
struct fscache_cache;
struct fscache_cache_ops;
struct fscache_object;
@@ -152,6 +153,9 @@ struct fscache_cache_ops {
int (*write)(struct fscache_object *object,
struct fscache_io_request *req,
struct iov_iter *iter);
+
+ /* Display object info in /proc/fs/fscache/objects */
+ int (*display_object)(struct seq_file *m, struct fscache_object *object);
};

extern struct fscache_cookie fscache_fsdef_index;