r22105: Added vfs_readahead module that appears to do wonderful things

for copying files from Samba when using Windows Vista Windows
explorer.... :-). By default if you add this I can go on my
vmware sessions from 7MB/sec to 12MB/sec (+1 extra MB/sec if
I turn sendfile on).
Jeremy.
(This used to be commit 97fdd67e83bb2706106a9bae95b32d8d9f8b4066)

3 files changed, 145 insertions, 1 deletions

diff --git a/source3/Makefile.in b/source3/Makefile.in
index e62ee9a571..8f9b775cc7 100644
--- a/source3/Makefile.in
+++ b/source3/Makefile.in
@@ -446,6 +446,7 @@ VFS_PREALLOC_OBJ = modules/vfs_prealloc.o
 VFS_COMMIT_OBJ = modules/vfs_commit.o
 VFS_GPFS_OBJ = modules/vfs_gpfs.o modules/gpfs.o modules/nfs4_acls.o
 VFS_NOTIFY_FAM_OBJ = modules/vfs_notify_fam.o
+VFS_LINUX_READAHEAD_OBJ = modules/vfs_readahead.o
 
 PLAINTEXT_AUTH_OBJ = auth/pampass.o auth/pass_check.o
 
@@ -1606,6 +1607,11 @@ bin/notify_fam.@SHLIBEXT@: $(VFS_NOTIFY_FAM_OBJ)
 	@$(SHLD) $(LDSHFLAGS) -o $@ $(VFS_NOTIFY_FAM_OBJ) \
 		@SONAMEFLAG@`basename $@`
 
+bin/readahead.@SHLIBEXT@: $(VFS_LINUX_READAHEAD_OBJ)
+	@echo "Building plugin $@"
+	@$(SHLD) $(LDSHFLAGS) -o $@ $(VFS_LINUX_READAHEAD_OBJ) \
+		@SONAMEFLAG@`basename $@`
+
 #########################################################
 ## IdMap NSS plugins
 
diff --git a/source3/configure.in b/source3/configure.in
index eb4bd9bcdc..326f81ca00 100644
--- a/source3/configure.in
+++ b/source3/configure.in
@@ -594,7 +594,7 @@ dnl These have to be built static:
 default_static_modules="pdb_smbpasswd pdb_tdbsam rpc_lsa rpc_samr rpc_winreg rpc_initshutdown rpc_lsa_ds rpc_wkssvc rpc_svcctl rpc_ntsvcs rpc_net rpc_netdfs rpc_srvsvc rpc_spoolss rpc_eventlog rpc_unixinfo rpc_epmapper auth_sam auth_unix auth_winbind auth_server auth_domain auth_builtin vfs_default nss_info_template"
 
 dnl These are preferably build shared, and static if dlopen() is not available
-default_shared_modules="vfs_recycle vfs_audit vfs_extd_audit vfs_full_audit vfs_netatalk vfs_fake_perms vfs_default_quota vfs_readonly vfs_cap vfs_expand_msdfs vfs_shadow_copy charset_CP850 charset_CP437 auth_script"
+default_shared_modules="vfs_recycle vfs_audit vfs_extd_audit vfs_full_audit vfs_netatalk vfs_fake_perms vfs_default_quota vfs_readonly vfs_cap vfs_expand_msdfs vfs_shadow_copy charset_CP850 charset_CP437 auth_script vfs_readahead"
 
 if test "x$developer" = xyes; then
    default_static_modules="$default_static_modules rpc_rpcecho"
@@ -5667,6 +5667,26 @@ if test x"$samba_cv_HAVE_LINUX_READAHEAD" = x"yes"; then
              [Whether Linux readahead is available])
 fi
 
+############################################
+# See if we have the posix_fadvise syscall.
+
+AC_CACHE_CHECK([for posix_fadvise],
+                samba_cv_HAVE_POSIX_FADVISE,[
+    AC_TRY_LINK([
+#if defined(HAVE_UNISTD_H)
+#include <unistd.h>
+#endif
+#include <fcntl.h>],
+    [ssize_t err = posix_fadvise(0,0,0x80000,POSIX_FADV_WILLNEED);],
+    samba_cv_HAVE_POSIX_FADVISE=yes,
+    samba_cv_HAVE_POSIX_FADVISE=no)])
+
+if test x"$samba_cv_HAVE_POSIX_FADVISE" = x"yes"; then
+  AC_DEFINE(HAVE_POSIX_FADVISE,1,
+             [Whether posix_fadvise is available])
+fi
+
+
 
 #################################################
 # Check whether winbind is supported on this platform.  If so we need to
@@ -6061,6 +6081,7 @@ SMB_MODULE(vfs_prealloc, \$(VFS_PREALLOC_OBJ), "bin/prealloc.$SHLIBEXT", VFS)
 SMB_MODULE(vfs_commit, \$(VFS_COMMIT_OBJ), "bin/commit.$SHLIBEXT", VFS)
 SMB_MODULE(vfs_gpfs, \$(VFS_GPFS_OBJ), "bin/gpfs.$SHLIBEXT", VFS)
 SMB_MODULE(vfs_notify_fam, \$(VFS_NOTIFY_FAM_OBJ), "bin/notify_fam.$SHLIBEXT", VFS)
+SMB_MODULE(vfs_readahead, \$(VFS_LINUX_READAHEAD_OBJ), "bin/readahead.$SHLIBEXT", VFS)
 
 SMB_SUBSYSTEM(VFS,smbd/vfs.o)
 
diff --git a/source3/modules/vfs_readahead.c b/source3/modules/vfs_readahead.c
new file mode 100644
index 0000000000..5b08f004c4
--- /dev/null
+++ b/source3/modules/vfs_readahead.c
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) Jeremy Allison 2007.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "includes.h"
+
+#if !defined(HAVE_LINUX_READAHEAD) && !defined(HAVE_POSIX_FADVISE)
+static BOOL didmsg;
+#endif
+
+/* 
+ * This module copes with Vista AIO read requests on Linux
+ * by detecting the initial 0x80000 boundary reads and causing
+ * the buffer cache to be filled in advance.
+ */
+
+static ssize_t readahead_sendfile(struct vfs_handle_struct *handle,
+					int tofd,
+					files_struct *fsp,
+					int fromfd,
+					const DATA_BLOB *header,
+					SMB_OFF_T offset,
+					size_t count)
+{
+	unsigned long off_bound = lp_parm_ulong(SNUM(handle->conn), "readahead", "offset", 0x80000);
+	if ( offset % off_bound == 0) {
+		unsigned long len = lp_parm_ulong(SNUM(handle->conn), "readahead", "length", off_bound);
+#if defined(HAVE_LINUX_READAHEAD)
+		int err = readahead(fromfd, offset, (size_t)len);
+		DEBUG(10,("readahead_sendfile: readahead on fd %u, offset %llu, len %u returned %d\n",
+			(unsigned int)fromfd,
+			(unsigned long long)offset,
+			(unsigned int)len,
+		        err ));
+#elif defined(HAVE_POSIX_FADVISE)
+		int err = posix_fadvise(fromfd, offset, (off_t)len, POSIX_FADV_WILLNEED);
+		DEBUG(10,("readahead_sendfile: posix_fadvise on fd %u, offset %llu, len %u returned %d\n",
+			(unsigned int)fromfd,
+			(unsigned long long)offset,
+			(unsigned int)len,
+			err ));
+#else
+		if (!didmsg) {
+			DEBUG(0,("readahead_sendfile: no readahead on this platform\n"));
+			didmsg = True;
+		}
+#endif
+	}
+	return SMB_VFS_NEXT_SENDFILE(handle,
+					tofd,
+					fsp,
+					fromfd,
+					header,
+					offset,
+					count);
+}
+
+static ssize_t readahead_pread(vfs_handle_struct *handle,
+				files_struct *fsp,
+				int fd,
+				void *data,
+				size_t count,
+				SMB_OFF_T offset)
+{
+	unsigned long off_bound = lp_parm_ulong(SNUM(handle->conn), "readahead", "offset", 0x80000);
+	if ( offset % off_bound == 0) {
+		unsigned long len = lp_parm_ulong(SNUM(handle->conn), "readahead", "length", off_bound);
+#if defined(HAVE_LINUX_READAHEAD)
+		int err = readahead(fd, offset, (size_t)len);
+		DEBUG(10,("readahead_pread: readahead on fd %u, offset %llu, len %u returned %d\n",
+			(unsigned int)fd,
+			(unsigned long long)offset,
+			(unsigned int)len,
+			err ));
+#elif defined(HAVE_POSIX_FADVISE)
+		int err = posix_fadvise(fromfd, offset, (off_t)len, POSIX_FADV_WILLNEED);
+		DEBUG(10,("readahead_pread: posix_fadvise on fd %u, offset %llu, len %u returned %d\n",
+			(unsigned int)fd,
+			(unsigned long long)offset,
+			(unsigned int)len,
+			(err ));
+#else
+		if (!didmsg) {
+			DEBUG(0,("readahead_pread: no readahead on this platform\n"));
+			didmsg = True;
+		}
+#endif
+        }
+        return SMB_VFS_NEXT_PREAD(handle, fsp, fd, data, count, offset);
+}
+
+static vfs_op_tuple readahead_ops [] =
+{
+	{SMB_VFS_OP(readahead_sendfile), SMB_VFS_OP_SENDFILE, SMB_VFS_LAYER_TRANSPARENT},
+	{SMB_VFS_OP(readahead_pread), SMB_VFS_OP_PREAD, SMB_VFS_LAYER_TRANSPARENT},
+	{SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
+};
+
+NTSTATUS vfs_readahead_init(void);
+NTSTATUS vfs_readahead_init(void)
+{
+	return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "readahead", readahead_ops);
+}