libnfs.c: add a simple dircache to libnfs

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>

diff --git a/lib/libnfs.c b/lib/libnfs.c
index 830e28e4e2df75ec2d08e9e92641d683cb9cf9f5..1328aed1cf81278e37163003f66e8f87c4e15a66 100644 (file)
--- a/lib/libnfs.c
+++ b/lib/libnfs.c
@@ -69,6 +69,7 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include "libnfs-zdr.h"
+#include "slist.h"
 #include "libnfs.h"
 #include "libnfs-raw.h"
 #include "libnfs-raw-mount.h"
@@ -76,7 +77,13 @@
 #include "libnfs-raw-portmap.h"
 #include "libnfs-private.h"
 
+#define MAX_DIR_CACHE 1024
+
 struct nfsdir {
+       struct nfs_fh3 fh;
+       fattr3 attr;
+       struct nfsdir *next;
+
        struct nfsdirent *entries;
        struct nfsdirent *current;
 };
@@ -96,6 +103,7 @@ struct nfs_context {
        uint64_t readmax;
        uint64_t writemax;
        char *cwd;
+       struct nfsdir *dircache;
 };
 
 void nfs_free_nfsdir(struct nfsdir *nfsdir)
@@ -108,9 +116,39 @@ void nfs_free_nfsdir(struct nfsdir *nfsdir)
                free(nfsdir->entries);
                nfsdir->entries = dirent;
        }
+       free(nfsdir->fh.data.data_val);
        free(nfsdir);
 }
 
+static void nfs_dircache_add(struct nfs_context *nfs, struct nfsdir *nfsdir)
+{
+       int i;
+       LIBNFS_LIST_ADD(&nfs->dircache, nfsdir);
+
+       for (nfsdir = nfs->dircache, i = 0; nfsdir; nfsdir = nfsdir->next, i++) {
+               if (i > MAX_DIR_CACHE) {
+                       LIBNFS_LIST_REMOVE(&nfs->dircache, nfsdir);
+                       nfs_free_nfsdir(nfsdir);
+                       break;
+               }
+       }
+}
+
+static struct nfsdir *nfs_dircache_find(struct nfs_context *nfs, struct nfs_fh3 *fh)
+{
+       struct nfsdir *nfsdir;
+
+       for (nfsdir = nfs->dircache; nfsdir; nfsdir = nfsdir->next) {
+               if (nfsdir->fh.data.data_len == fh->data.data_len &&
+                   !memcmp(nfsdir->fh.data.data_val, fh->data.data_val, fh->data.data_len)) {
+                       LIBNFS_LIST_REMOVE(&nfs->dircache, nfsdir);
+                       return nfsdir;
+               }
+       }
+
+       return NULL;
+}
+
 struct nfs_cb_data;
 typedef int (*continue_func)(struct nfs_context *nfs, fattr3 *attr,
                             struct nfs_cb_data *data);
@@ -379,6 +417,12 @@ void nfs_destroy_context(struct nfs_context *nfs)
                nfs->rootfh.data.data_val = NULL;
        }
 
+       while (nfs->dircache) {
+               struct nfsdir *nfsdir = nfs->dircache;
+               LIBNFS_LIST_REMOVE(&nfs->dircache, nfsdir);
+               nfs_free_nfsdir(nfsdir);
+       }
+
        free(nfs);
 }
 
@@ -2923,6 +2967,9 @@ static void nfs_opendir2_cb(struct rpc_context *rpc, int status, void *command_d
                return;
        }
 
+       if (res->READDIR3res_u.resok.dir_attributes.attributes_follow)
+               nfsdir->attr = res->READDIR3res_u.resok.dir_attributes.post_op_attr_u.attributes;
+
        /* steal the dirhandle */
        nfsdir->current = nfsdir->entries;
 
@@ -3083,6 +3130,9 @@ static void nfs_opendir_cb(struct rpc_context *rpc, int status, void *command_da
                return;
        }
 
+       if (res->READDIRPLUS3res_u.resok.dir_attributes.attributes_follow)
+               nfsdir->attr = res->READDIRPLUS3res_u.resok.dir_attributes.post_op_attr_u.attributes;
+
        /* steal the dirhandle */
        data->continue_data = NULL;
        nfsdir->current = nfsdir->entries;
@@ -3094,6 +3144,31 @@ static void nfs_opendir_cb(struct rpc_context *rpc, int status, void *command_da
 static int nfs_opendir_continue_internal(struct nfs_context *nfs, fattr3 *attr _U_, struct nfs_cb_data *data)
 {
        READDIRPLUS3args args;
+       struct nfsdir *nfsdir = data->continue_data;;
+       struct nfsdir *cached;
+
+       cached = nfs_dircache_find(nfs, &data->fh);
+       if (cached) {
+               if (attr && attr->mtime.seconds == cached->attr.mtime.seconds) {
+                       cached->current = cached->entries;
+                       data->cb(0, nfs, cached, data->private_data);
+                       free_nfs_cb_data(data);
+                       return 0;
+               } else {
+                       /* cache must be stale */
+                       nfs_free_nfsdir(cached);
+               }
+       }
+
+       nfsdir->fh.data.data_len  = data->fh.data.data_len;
+       nfsdir->fh.data.data_val = malloc(nfsdir->fh.data.data_len);
+       if (nfsdir->fh.data.data_val == NULL) {
+               rpc_set_error(nfs->rpc, "OOM when allocating fh for nfsdir");
+               data->cb(-ENOMEM, nfs, rpc_get_error(nfs->rpc), data->private_data);
+               free_nfs_cb_data(data);
+               return -1;
+       }
+       memcpy(nfsdir->fh.data.data_val, data->fh.data.data_val, data->fh.data.data_len);
 
        args.dir = data->fh;
        args.cookie = 0;
@@ -3143,9 +3218,9 @@ struct nfsdirent *nfs_readdir(struct nfs_context *nfs _U_, struct nfsdir *nfsdir
 /*
  * closedir()
  */
-void nfs_closedir(struct nfs_context *nfs _U_, struct nfsdir *nfsdir)
+void nfs_closedir(struct nfs_context *nfs, struct nfsdir *nfsdir)
 {
-       nfs_free_nfsdir(nfsdir);
+       nfs_dircache_add(nfs, nfsdir);
 }