2022-09-08 22:29:58

by Chuck Lever III

[permalink] [raw]
Subject: [PATCH v4 7/8] NFSD: Make nfsd4_rename() wait before returning NFS4ERR_DELAY

nfsd_rename() can kick off a CB_RECALL (via
vfs_rename() -> leases_conflict()) if a delegation is present.
Before returning NFS4ERR_DELAY, give the client holding that
delegation a chance to return it and then retry the nfsd_rename()
again, once.

This version of the patch handles renaming an existing file,
but does not deal with renaming onto an existing file. That
case will still always trigger an NFS4ERR_DELAY.

Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=354
Tested-by: Igor Mammedov <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>
---
fs/nfsd/vfs.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 03a826ccc165..b597cb2af949 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1681,7 +1681,15 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
.new_dir = tdir,
.new_dentry = ndentry,
};
- host_err = vfs_rename(&rd);
+ int retries;
+
+ for (retries = 1;;) {
+ host_err = vfs_rename(&rd);
+ if (host_err != -EAGAIN || !retries--)
+ break;
+ if (!nfsd_wait_for_delegreturn(rqstp, d_inode(odentry)))
+ break;
+ }
if (!host_err) {
host_err = commit_metadata(tfhp);
if (!host_err)