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From:   trondmy@kernel.org
To:     linux-nfs@vger.kernel.org
Subject: [PATCH v6 10/13] NFS: Don't request readdirplus when revaldation was forced
Date:   Mon, 21 Feb 2022 11:08:48 -0500
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From: Trond Myklebust <trond.myklebust@hammerspace.com>

If the revalidation was forced, due to the presence of a LOOKUP_EXCL or
a LOOKUP_REVAL flag, then readdirplus won't help. It also can't help
when we're doing a path component lookup.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/dir.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index b1e6c56d7e1a..b6e21c5e1a0f 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -665,10 +665,13 @@ void nfs_readdir_record_entry_cache_miss(struct inode *dir)
 	}
 }
 
-static void nfs_lookup_advise_force_readdirplus(struct inode *dir)
+static void nfs_lookup_advise_force_readdirplus(struct inode *dir,
+						unsigned int flags)
 {
 	if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))
 		return;
+	if (flags & (LOOKUP_EXCL | LOOKUP_PARENT | LOOKUP_REVAL))
+		return;
 	nfs_readdir_record_entry_cache_miss(dir);
 }
 
@@ -1582,15 +1585,17 @@ nfs_lookup_revalidate_delegated(struct inode *dir, struct dentry *dentry,
 	return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
 }
 
-static int
-nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
-			     struct inode *inode)
+static int nfs_lookup_revalidate_dentry(struct inode *dir,
+					struct dentry *dentry,
+					struct inode *inode, unsigned int flags)
 {
 	struct nfs_fh *fhandle;
 	struct nfs_fattr *fattr;
 	unsigned long dir_verifier;
 	int ret;
 
+	trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
+
 	ret = -ENOMEM;
 	fhandle = nfs_alloc_fhandle();
 	fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode));
@@ -1611,6 +1616,10 @@ nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
 		}
 		goto out;
 	}
+
+	/* Request help from readdirplus */
+	nfs_lookup_advise_force_readdirplus(dir, flags);
+
 	ret = 0;
 	if (nfs_compare_fh(NFS_FH(inode), fhandle))
 		goto out;
@@ -1620,8 +1629,6 @@ nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
 	nfs_setsecurity(inode, fattr);
 	nfs_set_verifier(dentry, dir_verifier);
 
-	/* set a readdirplus hint that we had a cache miss */
-	nfs_lookup_advise_force_readdirplus(dir);
 	ret = 1;
 out:
 	nfs_free_fattr(fattr);
@@ -1687,8 +1694,7 @@ nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
 	if (NFS_STALE(inode))
 		goto out_bad;
 
-	trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
-	return nfs_lookup_revalidate_dentry(dir, dentry, inode);
+	return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags);
 out_valid:
 	return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
 out_bad:
@@ -1882,7 +1888,7 @@ struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned in
 		goto out;
 
 	/* Notify readdir to use READDIRPLUS */
-	nfs_lookup_advise_force_readdirplus(dir);
+	nfs_lookup_advise_force_readdirplus(dir, flags);
 
 no_entry:
 	res = d_splice_alias(inode, dentry);
@@ -2145,7 +2151,7 @@ nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
 reval_dentry:
 	if (flags & LOOKUP_RCU)
 		return -ECHILD;
-	return nfs_lookup_revalidate_dentry(dir, dentry, inode);
+	return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags);
 
 full_reval:
 	return nfs_do_lookup_revalidate(dir, dentry, flags);
-- 
2.35.1