NFS: Be more aggressive in using readdirplus for 'ls -l' situations

Try to detect 'ls -l' by having nfs_getattr() look at whether or not
there is an opendir() file descriptor for the parent directory.
If so, then assume that we want to force use of readdirplus in order
to avoid the multiple GETATTR calls over the wire.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 38 insertions, 4 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index be38b573495a..c8e48c26418b 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -69,21 +69,28 @@ const struct address_space_operations nfs_dir_aops = {
 
 static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir, struct rpc_cred *cred)
 {
+	struct nfs_inode *nfsi = NFS_I(dir);
 	struct nfs_open_dir_context *ctx;
 	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
 	if (ctx != NULL) {
 		ctx->duped = 0;
-		ctx->attr_gencount = NFS_I(dir)->attr_gencount;
+		ctx->attr_gencount = nfsi->attr_gencount;
 		ctx->dir_cookie = 0;
 		ctx->dup_cookie = 0;
 		ctx->cred = get_rpccred(cred);
+		spin_lock(&dir->i_lock);
+		list_add(&ctx->list, &nfsi->open_files);
+		spin_unlock(&dir->i_lock);
 		return ctx;
 	}
 	return  ERR_PTR(-ENOMEM);
 }
 
-static void put_nfs_open_dir_context(struct nfs_open_dir_context *ctx)
+static void put_nfs_open_dir_context(struct inode *dir, struct nfs_open_dir_context *ctx)
 {
+	spin_lock(&dir->i_lock);
+	list_del(&ctx->list);
+	spin_unlock(&dir->i_lock);
 	put_rpccred(ctx->cred);
 	kfree(ctx);
 }
@@ -126,7 +133,7 @@ out:
 static int
 nfs_closedir(struct inode *inode, struct file *filp)
 {
-	put_nfs_open_dir_context(filp->private_data);
+	put_nfs_open_dir_context(filp->f_path.dentry->d_inode, filp->private_data);
 	return 0;
 }
 
@@ -437,6 +444,22 @@ void nfs_advise_use_readdirplus(struct inode *dir)
 	set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags);
 }
 
+/*
+ * This function is mainly for use by nfs_getattr().
+ *
+ * If this is an 'ls -l', we want to force use of readdirplus.
+ * Do this by checking if there is an active file descriptor
+ * and calling nfs_advise_use_readdirplus, then forcing a
+ * cache flush.
+ */
+void nfs_force_use_readdirplus(struct inode *dir)
+{
+	if (!list_empty(&NFS_I(dir)->open_files)) {
+		nfs_advise_use_readdirplus(dir);
+		nfs_zap_mapping(dir, dir->i_mapping);
+	}
+}
+
 static
 void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
 {
@@ -815,6 +838,17 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc)
 	goto out;
 }
 
+static bool nfs_dir_mapping_need_revalidate(struct inode *dir)
+{
+	struct nfs_inode *nfsi = NFS_I(dir);
+
+	if (nfs_attribute_cache_expired(dir))
+		return true;
+	if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+		return true;
+	return false;
+}
+
 /* The file offset position represents the dirent entry number.  A
    last cookie cache takes care of the common case of reading the
    whole directory.
@@ -847,7 +881,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
 	desc->plus = nfs_use_readdirplus(inode, ctx) ? 1 : 0;
 
 	nfs_block_sillyrename(dentry);
-	if (ctx->pos == 0 || nfs_attribute_cache_expired(inode))
+	if (ctx->pos == 0 || nfs_dir_mapping_need_revalidate(inode))
 		res = nfs_revalidate_mapping(inode, file->f_mapping);
 	if (res < 0)
 		goto out;