[SCM] Samba Shared Repository - branch master updated

[Jeremy Allison]

The branch, master has been updated
       via  56b7525 Sigh :-(. Removing optimization prematurely is the root of all evil :-(.
      from  23158d7 docs: Fix generating idmap manpages.

http://gitweb.samba.org/?p=samba.git;a=shortlog;h=master


- Log -----------------------------------------------------------------
commit 56b752512597acaffa94a979ef9140760e0f5cf3
Author: Jeremy Allison <jra at samba.org>
Date:   Thu Sep 13 10:13:21 2012 -0700

    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 at samba.org>
    Autobuild-Date(master): Thu Sep 13 21:31:42 CEST 2012 on sn-devel-104

-----------------------------------------------------------------------

Summary of changes:
 source3/smbd/globals.c |    1 +
 source3/smbd/globals.h |    1 +
 source3/smbd/vfs.c     |   13 +++++++++++++
 3 files changed, 15 insertions(+), 0 deletions(-)


Changeset truncated at 500 lines:

diff --git a/source3/smbd/globals.c b/source3/smbd/globals.c
index 874f35d..80f6a66 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 1cefe51..566f04d 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 7d19440..fe99ee2 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));


-- 
Samba Shared Repository