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Subject: [PATCH 08/13] NFSD: always drop directory lock in nfsd_unlink()
From:   NeilBrown <neilb@suse.de>
To:     Chuck Lever III <chuck.lever@oracle.com>,
        Jeff Layton <jlayton@kernel.org>
Cc:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Date:   Tue, 26 Jul 2022 16:45:30 +1000
Message-ID: <165881793058.21666.12825902860406411178.stgit@noble.brown>
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References: <165881740958.21666.5904057696047278505.stgit@noble.brown>
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Some error paths in nfsd_unlink() allow it to exit without unlocking the
directory.  This is not a problem in practice as the directory will be
locked with an fh_put(), but it is untidy and potentially confusing.

This allows us to remove all the fh_unlock() calls that are immediately
after nfsd_unlink() calls.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
---
 fs/nfsd/nfs3proc.c |    2 --
 fs/nfsd/nfs4proc.c |    4 +---
 fs/nfsd/vfs.c      |    7 +++++--
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 0060a89997d4..774e4a2ab9b1 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -480,7 +480,6 @@ nfsd3_proc_remove(struct svc_rqst *rqstp)
 	fh_copy(&resp->fh, &argp->fh);
 	resp->status = nfsd_unlink(rqstp, &resp->fh, -S_IFDIR,
 				   argp->name, argp->len);
-	fh_unlock(&resp->fh);
 	return rpc_success;
 }
 
@@ -501,7 +500,6 @@ nfsd3_proc_rmdir(struct svc_rqst *rqstp)
 	fh_copy(&resp->fh, &argp->fh);
 	resp->status = nfsd_unlink(rqstp, &resp->fh, S_IFDIR,
 				   argp->name, argp->len);
-	fh_unlock(&resp->fh);
 	return rpc_success;
 }
 
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 915c9457a571..1aa6ae4ec2f5 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1002,10 +1002,8 @@ nfsd4_remove(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		return nfserr_grace;
 	status = nfsd_unlink(rqstp, &cstate->current_fh, 0,
 			     remove->rm_name, remove->rm_namelen);
-	if (!status) {
-		fh_unlock(&cstate->current_fh);
+	if (!status)
 		set_change_info(&remove->rm_cinfo, &cstate->current_fh);
-	}
 	return status;
 }
 
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 877331fabae0..f15ceed6d184 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1742,12 +1742,12 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 	rdentry = lookup_one_len(fname, dentry, flen);
 	host_err = PTR_ERR(rdentry);
 	if (IS_ERR(rdentry))
-		goto out_drop_write;
+		goto out_unlock;
 
 	if (d_really_is_negative(rdentry)) {
 		dput(rdentry);
 		host_err = -ENOENT;
-		goto out_drop_write;
+		goto out_unlock;
 	}
 	rinode = d_inode(rdentry);
 	ihold(rinode);
@@ -1785,6 +1785,9 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 	}
 out:
 	return err;
+out_unlock:
+	fh_unlock(fhp);
+	goto out_drop_write;
 }
 
 /*