r16945: Sync trunk -> 3.0 for 3.0.24 code. Still need

to do the upper layer directories but this is what
everyone is waiting for....

Jeremy.
(This used to be commit 9dafb7f48ca3e7af956b0a7d1720c2546fc4cfb8)

1 files changed, 214 insertions, 0 deletions

diff --git a/source3/modules/vfs_prealloc.c b/source3/modules/vfs_prealloc.c
new file mode 100644
index 0000000000..94db642370
--- /dev/null
+++ b/source3/modules/vfs_prealloc.c
@@ -0,0 +1,214 @@
+/*
+ * XFS preallocation support module.
+ *
+ * Copyright (c) James Peach 2006
+ *
+ * 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"
+
+/* Extent preallocation module.
+ *
+ * The purpose of this module is to preallocate space on the filesystem when
+ * we have a good idea of how large files are supposed to be. This lets writes
+ * proceed without having to allocate new extents and results in better file
+ * layouts on disk.
+ *
+ * Currently only implemented for XFS. This module is based on an original idea
+ * and implementation by Sebastian Brings.
+ *
+ * Tunables.
+ *
+ *      prealloc: <ext>	    Number of bytes to preallocate for a file with
+ *			    the matching extension.
+ *      prealloc:debug	    Debug level at which to emit messages.
+ *
+ * Example.
+ *
+ *	prealloc:mpeg = 500M  # Preallocate *.mpeg to 500 MiB.
+ */
+
+#ifdef HAVE_XFS_LIBXFS_H
+#include <xfs/libxfs.h>
+#define lock_type xfs_flock64_t
+#else
+#define lock_type struct flock64
+#endif
+
+#define MODULE "prealloc"
+static int module_debug;
+
+static int preallocate_space(int fd, SMB_OFF_T size)
+{
+	lock_type fl = {0};
+	int err;
+
+	if (size <= 0) {
+		return 0;
+	}
+
+	fl.l_whence = SEEK_SET;
+	fl.l_start = 0;
+	fl.l_len = size;
+
+	/* IMPORTANT: We use RESVSP because we want the extents to be
+	 * allocated, but we don't want the allocation to show up in
+	 * st_size or persist after the close(2).
+	 */
+
+#if defined(XFS_IOC_RESVSP64)
+	/* On Linux this comes in via libxfs.h. */
+	err = xfsctl(NULL, fd, XFS_IOC_RESVSP64, &fl);
+#elif defined(F_RESVSP64)
+	/* On IRIX, this comes from fcntl.h. */
+	err = fcntl(fd, F_RESVSP64, &fl);
+#else
+	err = -1;
+	errno = ENOSYS;
+#endif
+
+	if (err) {
+		DEBUG(module_debug,
+			("%s: preallocate failed on fd=%d size=%lld: %s\n",
+			MODULE, fd, (long long)size, strerror(errno)));
+	}
+
+	return err;
+}
+
+static int prealloc_connect(
+                struct vfs_handle_struct *  handle,
+                const char *                service,
+                const char *                user)
+{
+	    module_debug = lp_parm_int(SNUM(handle->conn),
+					MODULE, "debug", 100);
+
+	    return SMB_VFS_NEXT_CONNECT(handle, service, user);
+}
+
+static int prealloc_open(vfs_handle_struct* handle,
+			const char *	    fname,
+			files_struct *	    fsp,
+			int		    flags,
+			mode_t		    mode)
+{
+	int fd;
+	off64_t size = 0;
+
+	const char * dot;
+	char fext[10];
+
+	if (!(flags & (O_CREAT|O_TRUNC))) {
+		/* Caller is not intending to rewrite the file. Let's not mess
+		 * with the allocation in this case.
+		 */
+		goto normal_open;
+	}
+
+	*fext = '\0';
+	dot = strrchr(fname, '.');
+	if (dot && *++dot) {
+		if (strlen(dot) < sizeof(fext)) {
+			strncpy(fext, dot, sizeof(fext));
+			strnorm(fext, CASE_LOWER);
+		}
+	}
+
+	if (*fext == '\0') {
+		goto normal_open;
+	}
+
+	/* Syntax for specifying preallocation size is:
+	 *	MODULE: <extension> = <size>
+	 * where
+	 *	<extension> is the file extension in lower case
+	 *	<size> is a size like 10, 10K, 10M
+	 */
+	size = conv_str_size(lp_parm_const_string(SNUM(handle->conn), MODULE,
+						    fext, NULL));
+	if (size <= 0) {
+		/* No need to preallocate this file. */
+		goto normal_open;
+	}
+
+	fd = SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode);
+	if (fd < 0) {
+		return fd;
+	}
+
+	/* Prellocate only if the file is being created or replaced. Note that
+	 * Samba won't ever pass down O_TRUNC, which is why we have to handle
+	 * truncate calls specially.
+	 */
+	if ((flags & O_CREAT) || (flags & O_TRUNC)) {
+		SMB_OFF_T * psize;
+
+		psize = VFS_ADD_FSP_EXTENSION(handle, fsp, SMB_OFF_T);
+		if (psize == NULL || *psize == -1) {
+			return fd;
+		}
+
+		DEBUG(module_debug,
+			("%s: preallocating %s (fd=%d) to %lld bytes\n",
+			MODULE, fname, fd, (long long)size));
+
+		*psize = size;
+		if (preallocate_space(fd, *psize) < 0) {
+			VFS_REMOVE_FSP_EXTENSION(handle, fsp);
+		}
+	}
+
+	return fd;
+
+normal_open:
+	/* We are not creating or replacing a file. Skip the
+	 * preallocation.
+	 */
+	DEBUG(module_debug, ("%s: skipping preallocation for %s\n",
+		    MODULE, fname));
+	return SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode);
+}
+
+static int prealloc_ftruncate(vfs_handle_struct * handle,
+			files_struct *	fsp,
+			int		fd,
+			SMB_OFF_T	offset)
+{
+	SMB_OFF_T *psize;
+	int ret = SMB_VFS_NEXT_FTRUNCATE(handle, fsp, fd, offset);
+
+	/* Maintain the allocated space even in the face of truncates. */
+	if ((psize = VFS_FETCH_FSP_EXTENSION(handle, fsp))) {
+		preallocate_space(fd, *psize);
+	}
+
+	return ret;
+}
+
+static vfs_op_tuple prealloc_op_tuples[] = {
+	{SMB_VFS_OP(prealloc_open), SMB_VFS_OP_OPEN, SMB_VFS_LAYER_TRANSPARENT},
+	{SMB_VFS_OP(prealloc_ftruncate), SMB_VFS_OP_FTRUNCATE, SMB_VFS_LAYER_TRANSPARENT},
+	{SMB_VFS_OP(prealloc_connect), SMB_VFS_OP_CONNECT, SMB_VFS_LAYER_TRANSPARENT},
+	{NULL,	SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
+};
+
+NTSTATUS vfs_prealloc_init(void)
+{
+	return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
+		MODULE, prealloc_op_tuples);
+}
+