This is a note to let you know that I've just added the patch titled
nfsd: Fix a write performance regression
to the 5.10-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-fix-a-write-performance-regression.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2376f01129994dc452640a08579a30b55a22629d
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Thu Mar 31 09:54:01 2022 -0400
nfsd: Fix a write performance regression
[ Upstream commit 6b8a94332ee4f7d9a8ae0cbac7609f79c212f06c ]
The call to filemap_flush() in nfsd_file_put() is there to ensure that
we clear out any writes belonging to a NFSv3 client relatively quickly
and avoid situations where the file can't be evicted by the garbage
collector. It also ensures that we detect write errors quickly.
The problem is this causes a regression in performance for some
workloads.
So try to improve matters by deferring writeback until we're ready to
close the file, and need to detect errors so that we can force the
client to resend.
Tested-by: Jan Kara <jack@xxxxxxx>
Fixes: b6669305d35a ("nfsd: Reduce the number of calls to nfsd_file_gc()")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20220330103457.r4xrhy2d6nhtouzk@xxxxxxxxxx
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index cc2831cec6695..496f7b3f75237 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -235,6 +235,13 @@ nfsd_file_check_write_error(struct nfsd_file *nf)
return filemap_check_wb_err(file->f_mapping, READ_ONCE(file->f_wb_err));
}
+static void
+nfsd_file_flush(struct nfsd_file *nf)
+{
+ if (nf->nf_file && vfs_fsync(nf->nf_file, 1) != 0)
+ nfsd_reset_write_verifier(net_generic(nf->nf_net, nfsd_net_id));
+}
+
static void
nfsd_file_do_unhash(struct nfsd_file *nf)
{
@@ -302,11 +309,14 @@ nfsd_file_put(struct nfsd_file *nf)
return;
}
- filemap_flush(nf->nf_file->f_mapping);
is_hashed = test_bit(NFSD_FILE_HASHED, &nf->nf_flags) != 0;
- nfsd_file_put_noref(nf);
- if (is_hashed)
+ if (!is_hashed) {
+ nfsd_file_flush(nf);
+ nfsd_file_put_noref(nf);
+ } else {
+ nfsd_file_put_noref(nf);
nfsd_file_schedule_laundrette();
+ }
if (atomic_long_read(&nfsd_filecache_count) >= NFSD_FILE_LRU_LIMIT)
nfsd_file_gc();
}
@@ -327,6 +337,7 @@ nfsd_file_dispose_list(struct list_head *dispose)
while(!list_empty(dispose)) {
nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
list_del(&nf->nf_lru);
+ nfsd_file_flush(nf);
nfsd_file_put_noref(nf);
}
}
@@ -340,6 +351,7 @@ nfsd_file_dispose_list_sync(struct list_head *dispose)
while(!list_empty(dispose)) {
nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
list_del(&nf->nf_lru);
+ nfsd_file_flush(nf);
if (!refcount_dec_and_test(&nf->nf_ref))
continue;
if (nfsd_file_free(nf))
