NFS: Be more targeted about readdirplus use when doing lookup/revalidation

There is little point in setting NFS_INO_ADVISE_RDPLUS in nfs_lookup and
nfs_lookup_revalidate() unless a process is actually doing readdir on the
parent directory.
Furthermore, there is little point in using readdirplus if we're trying
to revalidate a negative dentry.

Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 9220bc7b9cd778c1978d9317b72096e890551f6e..22835150579aef2d0ca97e0a959681843423f0bb 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -455,14 +455,18 @@ bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx)
 }
 
 /*
- * This function is called by the lookup code to request the use of
- * readdirplus to accelerate any future lookups in the same
+ * This function is called by the lookup and getattr code to request the
+ * use of readdirplus to accelerate any future lookups in the same
  * directory.
  */
 static
 void nfs_advise_use_readdirplus(struct inode *dir)
 {
-       set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags);
+       struct nfs_inode *nfsi = NFS_I(dir);
+
+       if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
+           !list_empty(&nfsi->open_files))
+               set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
 }
 
 /*
@@ -475,8 +479,11 @@ void nfs_advise_use_readdirplus(struct inode *dir)
  */
 void nfs_force_use_readdirplus(struct inode *dir)
 {
-       if (!list_empty(&NFS_I(dir)->open_files)) {
-               nfs_advise_use_readdirplus(dir);
+       struct nfs_inode *nfsi = NFS_I(dir);
+
+       if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
+           !list_empty(&nfsi->open_files)) {
+               set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
                invalidate_mapping_pages(dir->i_mapping, 0, -1);
        }
 }
@@ -1150,7 +1157,7 @@ static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
                                return -ECHILD;
                        goto out_bad;
                }
-               goto out_valid_noent;
+               goto out_valid;
        }
 
        if (is_bad_inode(inode)) {
@@ -1173,6 +1180,7 @@ static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
                                return -ECHILD;
                        goto out_zap_parent;
                }
+               nfs_advise_use_readdirplus(dir);
                goto out_valid;
        }
 
@@ -1208,12 +1216,12 @@ static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
        nfs_free_fhandle(fhandle);
        nfs4_label_free(label);
 
+       /* set a readdirplus hint that we had a cache miss */
+       nfs_force_use_readdirplus(dir);
+
 out_set_verifier:
        nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
  out_valid:
-       /* Success: notify readdir to use READDIRPLUS */
-       nfs_advise_use_readdirplus(dir);
- out_valid_noent:
        if (flags & LOOKUP_RCU) {
                if (parent != ACCESS_ONCE(dentry->d_parent))
                        return -ECHILD;
@@ -1413,8 +1421,8 @@ struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned in
        if (IS_ERR(res))
                goto out_label;
 
-       /* Success: notify readdir to use READDIRPLUS */
-       nfs_advise_use_readdirplus(dir);
+       /* Notify readdir to use READDIRPLUS */
+       nfs_force_use_readdirplus(dir);
 
 no_entry:
        res = d_splice_alias(inode, dentry);