Commit c5e4d5e9 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'fscache-fixes-20220831' of... 

Merge tag 'fscache-fixes-20220831' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull fscache/cachefiles fixes from David Howells:

 - Fix kdoc on fscache_use/unuse_cookie().

 - Fix the error returned by cachefiles_ondemand_copen() from an upcall
   result.

 - Fix the distribution of requests in on-demand mode in cachefiles to
   be fairer by cycling through them rather than picking the one with
   the lowest ID each time (IDs being reused).

* tag 'fscache-fixes-20220831' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  cachefiles: make on-demand request distribution fairer
  cachefiles: fix error return code in cachefiles_ondemand_copen()
  fscache: fix misdocumented parameter
parents a1f76426 1122f400

fs/cachefiles/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ struct cachefiles_cache { 
	char				*tag;		/* cache binding tag */

	refcount_t			unbind_pincount;/* refcount to do daemon unbind */

	struct xarray			reqs;		/* xarray of pending on-demand requests */

	unsigned long			req_id_next;

	struct xarray			ondemand_ids;	/* xarray for ondemand_id allocation */

	u32				ondemand_id_next;

};

fs/cachefiles/ondemand.c

+16 −6
Original line number Diff line number Diff line
@@ -158,9 +158,13 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) 


	/* fail OPEN request if daemon reports an error */

	if (size < 0) {

		if (!IS_ERR_VALUE(size))

			size = -EINVAL;

		if (!IS_ERR_VALUE(size)) {

			req->error = -EINVAL;

			ret = -EINVAL;

		} else {

			req->error = size;

			ret = 0;

		}

		goto out;

	}
@@ -238,14 +242,19 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, 
	unsigned long id = 0;

	size_t n;

	int ret = 0;

	XA_STATE(xas, &cache->reqs, 0);

	XA_STATE(xas, &cache->reqs, cache->req_id_next);



	/*

	 * Search for a request that has not ever been processed, to prevent

	 * requests from being processed repeatedly.

	 * Cyclically search for a request that has not ever been processed,

	 * to prevent requests from being processed repeatedly, and make

	 * request distribution fair.

	 */

	xa_lock(&cache->reqs);

	req = xas_find_marked(&xas, UINT_MAX, CACHEFILES_REQ_NEW);

	if (!req && cache->req_id_next > 0) {

		xas_set(&xas, 0);

		req = xas_find_marked(&xas, cache->req_id_next - 1, CACHEFILES_REQ_NEW);

	}

	if (!req) {

		xa_unlock(&cache->reqs);

		return 0;
@@ -260,6 +269,7 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, 
	}



	xas_clear_mark(&xas, CACHEFILES_REQ_NEW);

	cache->req_id_next = xas.xa_index + 1;

	xa_unlock(&cache->reqs);



	id = xas.xa_index;

include/linux/fscache.h

+2 −2
Original line number Diff line number Diff line
@@ -258,7 +258,7 @@ struct fscache_cookie *fscache_acquire_cookie(struct fscache_volume *volume, 


/**

 * fscache_use_cookie - Request usage of cookie attached to an object

 * @object: Object description

 * @cookie: The cookie representing the cache object

 * @will_modify: If cache is expected to be modified locally

 *

 * Request usage of the cookie attached to an object.  The caller should tell
@@ -274,7 +274,7 @@ static inline void fscache_use_cookie(struct fscache_cookie *cookie, 


/**

 * fscache_unuse_cookie - Cease usage of cookie attached to an object

 * @object: Object description

 * @cookie: The cookie representing the cache object

 * @aux_data: Updated auxiliary data (or NULL)

 * @object_size: Revised size of the object (or NULL)

 *