This is a note to let you know that I've just added the patch titled
nfsd: add some comments to nfsd_file_do_acquire
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-add-some-comments-to-nfsd_file_do_acquire.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d6b492fb13dfa81b95983ee0f692a08d9bc09ca3
Author: Jeff Layton <jlayton@xxxxxxxxxx>
Date: Thu Jan 5 07:15:12 2023 -0500
nfsd: add some comments to nfsd_file_do_acquire
[ Upstream commit b680cb9b737331aad271feebbedafb865504e234 ]
David Howells mentioned that he found this bit of code confusing, so
sprinkle in some comments to clarify.
Reported-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 43bb2fd47cf58..faa0c7d0253eb 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -1093,6 +1093,11 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
rcu_read_unlock();
if (nf) {
+ /*
+ * If the nf is on the LRU then it holds an extra reference
+ * that must be put if it's removed. It had better not be
+ * the last one however, since we should hold another.
+ */
if (nfsd_file_lru_remove(nf))
WARN_ON_ONCE(refcount_dec_and_test(&nf->nf_ref));
goto wait_for_construction;
