Merge tag 'fscache-next-20210829' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull fscache updates from David Howells:
 "Preparatory work for the fscache rewrite that's being worked on and
  fix some bugs. These include:

   - Always select netfs stats when enabling fscache stats since they're
     displayed through the same procfile.

   - Add a cookie debug ID that can be used in tracepoints instead of a
     pointer and cache it in the netfs_cache_resources struct rather
     than in the netfs_read_request struct to make it more available.

   - Use file_inode() in cachefiles rather than dereferencing
     file->f_inode directly.

   - Provide a procfile to display fscache cookies.

   - Remove the fscache and cachefiles histogram procfiles.

   - Remove the fscache object list procfile.

   - Avoid using %p in fscache and cachefiles as the value is hashed and
     not comparable to the register dump in an oops trace.

   - Fix the cookie hash function to actually achieve useful dispersion.

   - Fix fscache_cookie_put() so that it doesn't dereference the cookie
     pointer in the tracepoint after the refcount has been decremented
     (we're only allowed to do that if we decremented it to zero).

   - Use refcount_t rather than atomic_t for the fscache_cookie
     refcount"

* tag 'fscache-next-20210829' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  fscache: Use refcount_t for the cookie refcount instead of atomic_t
  fscache: Fix fscache_cookie_put() to not deref after dec
  fscache: Fix cookie key hashing
  cachefiles: Change %p in format strings to something else
  fscache: Change %p in format strings to something else
  fscache: Remove the object list procfile
  fscache, cachefiles: Remove the histogram stuff
  fscache: Procfile to display cookies
  fscache: Add a cookie debug ID and use that in traces
  cachefiles: Use file_inode() rather than accessing ->f_inode
  netfs: Move cookie debug ID to struct netfs_cache_resources
  fscache: Select netfs stats if fscache stats are enabled

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index abc1c4737fb8..a4dab5998613 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -123,15 +123,17 @@ struct fscache_netfs {
  * - indices are created on disk just-in-time
  */
 struct fscache_cookie {
-	atomic_t			usage;		/* number of users of this cookie */
+	refcount_t			ref;		/* number of users of this cookie */
 	atomic_t			n_children;	/* number of children of this cookie */
 	atomic_t			n_active;	/* number of active users of netfs ptrs */
+	unsigned int			debug_id;
 	spinlock_t			lock;
 	spinlock_t			stores_lock;	/* lock on page store tree */
 	struct hlist_head		backing_objects; /* object(s) backing this file/index */
 	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 */