This is a note to let you know that I've just added the patch titled
nfsd: Reduce contention for the nfsd_file nf_rwsem
to the 5.13-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-reduce-contention-for-the-nfsd_file-nf_rwsem.patch
and it can be found in the queue-5.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4d4cc15f278160bf3e36b1efe901c61870c2bf24
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Thu Jun 17 19:26:52 2021 -0400
nfsd: Reduce contention for the nfsd_file nf_rwsem
[ Upstream commit 474bc334698df98ce07c890f1898c7e7f389b0c7 ]
When flushing out the unstable file writes as part of a COMMIT call, try
to perform most of of the data writes and waits outside the semaphore.
This means that if the client is sending the COMMIT as part of a memory
reclaim operation, then it can continue performing I/O, with contention
for the lock occurring only once the data sync is finished.
Fixes: 5011af4c698a ("nfsd: Fix stable writes")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Tested-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 15adf1f6ab21..46485c04740d 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1123,6 +1123,19 @@ out:
}
#ifdef CONFIG_NFSD_V3
+static int
+nfsd_filemap_write_and_wait_range(struct nfsd_file *nf, loff_t offset,
+ loff_t end)
+{
+ struct address_space *mapping = nf->nf_file->f_mapping;
+ int ret = filemap_fdatawrite_range(mapping, offset, end);
+
+ if (ret)
+ return ret;
+ filemap_fdatawait_range_keep_errors(mapping, offset, end);
+ return 0;
+}
+
/*
* Commit all pending writes to stable storage.
*
@@ -1153,10 +1166,11 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
if (err)
goto out;
if (EX_ISSYNC(fhp->fh_export)) {
- int err2;
+ int err2 = nfsd_filemap_write_and_wait_range(nf, offset, end);
down_write(&nf->nf_rwsem);
- err2 = vfs_fsync_range(nf->nf_file, offset, end, 0);
+ if (!err2)
+ err2 = vfs_fsync_range(nf->nf_file, offset, end, 0);
switch (err2) {
case 0:
nfsd_copy_boot_verifier(verf, net_generic(nf->nf_net,
