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-rw-r--r--fs/nfsd/filecache.c39
1 files changed, 31 insertions, 8 deletions
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 5cb8cce15..697acf5c3 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -1,7 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
/*
- * Open file cache.
+ * The NFSD open file cache.
*
* (c) 2015 - Jeff Layton <jeff.layton@primarydata.com>
+ *
+ * An nfsd_file object is a per-file collection of open state that binds
+ * together:
+ * - a struct file *
+ * - a user credential
+ * - a network namespace
+ * - a read-ahead context
+ * - monitoring for writeback errors
+ *
+ * nfsd_file objects are reference-counted. Consumers acquire a new
+ * object via the nfsd_file_acquire API. They manage their interest in
+ * the acquired object, and hence the object's reference count, via
+ * nfsd_file_get and nfsd_file_put. There are two varieties of nfsd_file
+ * object:
+ *
+ * * non-garbage-collected: When a consumer wants to precisely control
+ * the lifetime of a file's open state, it acquires a non-garbage-
+ * collected nfsd_file. The final nfsd_file_put releases the open
+ * state immediately.
+ *
+ * * garbage-collected: When a consumer does not control the lifetime
+ * of open state, it acquires a garbage-collected nfsd_file. The
+ * final nfsd_file_put allows the open state to linger for a period
+ * during which it may be re-used.
*/
#include <linux/hash.h>
@@ -186,12 +211,9 @@ static const struct rhashtable_params nfsd_file_rhash_params = {
static void
nfsd_file_schedule_laundrette(void)
{
- if ((atomic_read(&nfsd_file_rhash_tbl.nelems) == 0) ||
- test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 0)
- return;
-
- queue_delayed_work(system_wq, &nfsd_filecache_laundrette,
- NFSD_LAUNDRETTE_DELAY);
+ if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags))
+ queue_delayed_work(system_wq, &nfsd_filecache_laundrette,
+ NFSD_LAUNDRETTE_DELAY);
}
static void
@@ -589,7 +611,8 @@ static void
nfsd_file_gc_worker(struct work_struct *work)
{
nfsd_file_gc();
- nfsd_file_schedule_laundrette();
+ if (list_lru_count(&nfsd_file_lru))
+ nfsd_file_schedule_laundrette();
}
static unsigned long