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authorJeremy Allison <jra@samba.org>2012-09-13 10:13:21 -0700
committerJeremy Allison <jra@samba.org>2012-09-13 21:31:42 +0200
commit56b752512597acaffa94a979ef9140760e0f5cf3 (patch)
tree8a54245369ad6042366f4d24bffadd298efbecc4
parent23158d72c8de9318e1f136331ef4d788df243af7 (diff)
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Sigh :-(. Removing optimization prematurely is the root of all evil :-(.
Sorry for the mistake, but the LastDir singleton cache in vfs_ChDir() actually plays an important role. When we're processing a stream of SMB1/SMB2/SMB3 requests we don't want to add a chdir()/getcwd() system call pair on every request if they're all on the same connection and dealing with the same base path. I did some testing with a program that times 1,000,000 chdir() requests vs. 1,000,000 strcmp requests and it's a penalty of 10x doing the system calls. Just because it's old code, doesn't mean it's bad :-(. Autobuild-User(master): Jeremy Allison <jra@samba.org> Autobuild-Date(master): Thu Sep 13 21:31:42 CEST 2012 on sn-devel-104
-rw-r--r--source3/smbd/globals.c1
-rw-r--r--source3/smbd/globals.h1
-rw-r--r--source3/smbd/vfs.c13
3 files changed, 15 insertions, 0 deletions
diff --git a/source3/smbd/globals.c b/source3/smbd/globals.c
index 874f35d1f6..80f6a66427 100644
--- a/source3/smbd/globals.c
+++ b/source3/smbd/globals.c
@@ -85,6 +85,7 @@ int conn_ctx_stack_ndx = 0;
struct vfs_init_function_entry *backends = NULL;
char *sparse_buf = NULL;
+char *LastDir = NULL;
struct smbd_parent_context *am_parent = NULL;
struct memcache *smbd_memcache_ctx = NULL;
diff --git a/source3/smbd/globals.h b/source3/smbd/globals.h
index 1cefe51faa..566f04d71f 100644
--- a/source3/smbd/globals.h
+++ b/source3/smbd/globals.h
@@ -101,6 +101,7 @@ extern int conn_ctx_stack_ndx;
struct vfs_init_function_entry;
extern struct vfs_init_function_entry *backends;
extern char *sparse_buf;
+extern char *LastDir;
struct smbd_parent_context;
extern struct smbd_parent_context *am_parent;
diff --git a/source3/smbd/vfs.c b/source3/smbd/vfs.c
index 7d194404f4..fe99ee29e9 100644
--- a/source3/smbd/vfs.c
+++ b/source3/smbd/vfs.c
@@ -801,14 +801,27 @@ int vfs_ChDir(connection_struct *conn, const char *path)
{
int ret;
+ if (!LastDir) {
+ LastDir = SMB_STRDUP("");
+ }
+
if (strcsequal(path,".")) {
return 0;
}
+ if (*path == '/' && strcsequal(LastDir,path)) {
+ return 0;
+ }
+
DEBUG(4,("vfs_ChDir to %s\n",path));
ret = SMB_VFS_CHDIR(conn,path);
if (ret == 0) {
+ /* Global cache. */
+ SAFE_FREE(LastDir);
+ LastDir = SMB_STRDUP(path);
+
+ /* conn cache. */
TALLOC_FREE(conn->cwd);
conn->cwd = vfs_GetWd(conn, conn);
DEBUG(4,("vfs_ChDir got %s\n",conn->cwd));