[PATCH] nfsd: Reduce contention for the nfsd_file nf_rwsem
From: trondmy@kernel.org
Date: 2021-06-17 23:26:56
Subsystem:
filesystems (vfs and infrastructure), kernel nfsd, sunrpc, and lockd servers, the rest · Maintainers:
Alexander Viro, Christian Brauner, Chuck Lever, Jeff Layton, Linus Torvalds
From: Trond Myklebust <redacted>
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 <redacted>
---
fs/nfsd/vfs.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
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 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, } #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,
--
2.31.1