Add a gpfs_prefetch module

This can not go upstream yet because it uses the non-GPL libgpfs. So it will
not be compiled by default and will not be included in the SOFS RPMs. But upon
Sven's request, we include it in the git tree and the source RPMs, so that it
can be built for in-house tests.
(This used to be commit fc9b30bed2d774dca6660b497cb50f982b23b885)

1 files changed, 308 insertions, 0 deletions

diff --git a/source3/modules/vfs_gpfs_prefetch.c b/source3/modules/vfs_gpfs_prefetch.c
new file mode 100644
index 0000000000..77f265fc24
--- /dev/null
+++ b/source3/modules/vfs_gpfs_prefetch.c
@@ -0,0 +1,308 @@
+/*
+   Unix SMB/CIFS implementation.
+   Make use of gpfs prefetch functionality
+
+   Copyright (C) Volker Lendecke 2008
+
+   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 3 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, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#include "includes.h"
+
+#undef DBGC_CLASS
+#define DBGC_CLASS DBGC_VFS
+
+#include <gpfs.h>
+#include <gpfs_fcntl.h>
+
+static int (*gpfs_fcntl_fn)(int fd, void *arg);
+
+static int smbd_gpfs_fcntl(int fd, void *arg)
+{
+	static void *libgpfs_handle = NULL;
+
+	DEBUG(10, ("smbd_gpfs_fcntl called for %d\n", fd));
+
+	if (gpfs_fcntl_fn == NULL) {
+		libgpfs_handle = sys_dlopen("libgpfs.so", RTLD_LAZY);
+
+		if (libgpfs_handle == NULL) {
+			DEBUG(10, ("sys_dlopen for libgpfs failed: %s\n",
+				   strerror(errno)));
+			return;
+		}
+
+		gpfs_fcntl_fn = sys_dlsym(libgpfs_handle, "gpfs_fcntl");
+		if (gpfs_fcntl_fn == NULL) {
+			DEBUG(3, ("libgpfs.so does not contain the symbol "
+				  "'gpfs_fcntl'\n"));
+			errno = ENOSYS;
+			return -1;
+		}
+	}
+
+	return gpfs_fcntl_fn(fd, arg);
+}
+
+struct gpfs_prefetch_config {
+	name_compare_entry *namelist;
+	size_t size;
+};
+
+struct gpfs_prefetch_hints {
+	blksize_t st_blksize;
+	/*
+	 * The current center around which config->size bytes are
+	 * prefetched
+	 */
+	SMB_OFF_T center;
+};
+
+static void gpfs_prefetch_recenter(vfs_handle_struct *handle,
+				   files_struct *fsp,
+				   SMB_OFF_T offset, size_t size,
+				   struct gpfs_prefetch_hints *hints)
+{
+	int ret;
+	SMB_OFF_T new_center;
+
+	struct {
+		gpfsFcntlHeader_t hdr;
+		gpfsMultipleAccessRange_t acc;
+	} arg;
+
+
+	if (hints->st_blksize == 0) {
+		SMB_STRUCT_STAT sbuf;
+
+		if (SMB_VFS_NEXT_FSTAT(handle, fsp, &sbuf) == -1) {
+			return;
+		}
+		DEBUG(10, ("gpfs_prefetch_recenter: st_blksize = %d\n",
+			   (int)sbuf.st_blksize));
+		hints->st_blksize = sbuf.st_blksize;
+	}
+
+	new_center = (offset > size) ? offset : 0;
+
+	DEBUG(10, ("gpfs_prefetch_recenter: size=%d, offset=%d, "
+		   "old_center=%d, new_center=%d\n", (int)size, (int)offset,
+		   (int)hints->center, (int)new_center));
+
+	ZERO_STRUCT(arg);
+
+	arg.hdr.totalLength = sizeof(arg);
+	arg.hdr.fcntlVersion = GPFS_FCNTL_CURRENT_VERSION;
+	arg.hdr.fcntlReserved = 0;
+	arg.acc.structLen = sizeof(arg.acc);
+	arg.acc.structType = GPFS_MULTIPLE_ACCESS_RANGE;
+	arg.acc.accRangeCnt = 1;
+	arg.acc.relRangeCnt = 1;
+
+	arg.acc.accRangeArray[0].blockNumber = new_center/hints->st_blksize;
+	arg.acc.accRangeArray[0].start = 0;
+	arg.acc.accRangeArray[0].length = size;
+	arg.acc.accRangeArray[0].isWrite = 0;
+
+	arg.acc.relRangeArray[0].blockNumber = hints->center/hints->st_blksize;
+	arg.acc.relRangeArray[0].start = 0;
+	arg.acc.relRangeArray[0].length = size;
+	arg.acc.relRangeArray[0].isWrite = 0;
+
+	ret = smbd_gpfs_fcntl(fsp->fh->fd, &arg);
+	if (ret == -1) {
+		DEBUG(5, ("gpfs_fcntl returned %s\n", strerror(errno)));
+	}
+
+	hints->center = new_center;
+}
+
+static ssize_t gpfs_prefetch_pread(vfs_handle_struct *handle,
+				   files_struct *fsp, void *data,
+				   size_t n, SMB_OFF_T offset)
+{
+	struct gpfs_prefetch_config *config =
+		(struct gpfs_prefetch_config *)handle->data;
+	struct gpfs_prefetch_hints *hints = (struct gpfs_prefetch_hints *)
+		VFS_FETCH_FSP_EXTENSION(handle, fsp);
+	SMB_OFF_T out_of_center;
+
+	/*
+	 * How far away from the center of the prefetch region is the
+	 * request?
+	 */
+
+	out_of_center = (offset > hints->center)
+		? (offset - hints->center) : (hints->center - offset);
+
+	DEBUG(10, ("gpfs_prefetch_pread: n=%d, offset=%d, center=%d, "
+		   "out_of_center=%d, size=%d\n", (int)n, (int)offset,
+		   (int)hints->center, (int)out_of_center,
+		   (int)config->size));
+	/*
+	 * Are we completely out of the prefetch range or less than
+	 * 10% at its borders?
+	 */
+
+	if ((out_of_center > config->size)
+	    || ((config->size - out_of_center) * 10 < config->size)) {
+		/*
+		 * Re-center the prefetch area
+		 */
+		gpfs_prefetch_recenter(handle, fsp, offset, config->size,
+				       hints);
+	}
+
+	return SMB_VFS_NEXT_PREAD(handle, fsp, data, n, offset);
+}
+
+static int gpfs_prefetch_open(vfs_handle_struct *handle,  const char *fname,
+			      files_struct *fsp, int flags, mode_t mode)
+{
+	int fd, ret;
+	struct gpfs_prefetch_hints *hints;
+	struct gpfs_prefetch_config *config =
+		(struct gpfs_prefetch_config *)handle->data;
+
+	struct {
+		gpfsFcntlHeader_t hdr;
+		gpfsAccessRange_t acc;
+	} arg;
+
+	DEBUG(10, ("gpfs_prefetch_open called for %s, config=%p, "
+		   "config->namelist = %p, config->size=%d\n", fname,
+		   config, config->namelist, (int)config->size));
+
+	if (!is_in_path(fname, config->namelist,
+			handle->conn->case_sensitive)) {
+		DEBUG(10, ("gpfs_prefetch_open not in list: %s\n", fname));
+		return SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode);
+	}
+
+	hints = (struct gpfs_prefetch_hints *)VFS_ADD_FSP_EXTENSION(
+		handle, fsp, struct gpfs_prefetch_hints);
+	if (hints == NULL) {
+		errno = ENOMEM;
+		return -1;
+	}
+
+	fd = SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode);
+	if (fd == -1) {
+		VFS_REMOVE_FSP_EXTENSION(handle, fsp);
+		return -1;
+	}
+
+	arg.hdr.totalLength = sizeof(arg);
+	arg.hdr.fcntlVersion = GPFS_FCNTL_CURRENT_VERSION;
+	arg.hdr.fcntlReserved = 0;
+	arg.acc.structLen = sizeof(arg.acc);
+	arg.acc.structType = GPFS_ACCESS_RANGE;
+	arg.acc.start = 0;
+	arg.acc.length = 1;
+	arg.acc.isWrite = 0;
+
+	ret = smbd_gpfs_fcntl(fd, &arg);
+	if (ret == -1) {
+		DEBUG(5, ("gpfs_fcntl returned %s\n", strerror(errno)));
+	}
+
+	hints->st_blksize = 0;
+	hints->center = 0;
+
+	return fd;
+}
+
+static void gpfs_prefetch_config_free(void **data)
+{
+	struct gpfs_prefetch_config **config =
+		(struct gpfs_prefetch_config **)data;
+
+	free_namearray((*config)->namelist);
+	TALLOC_FREE(*config);
+}
+
+static int gpfs_prefetch_connect(struct vfs_handle_struct *handle,
+				 const char *service,
+				 const char *user)
+{
+	struct gpfs_prefetch_config *config;
+	const char *mask;
+
+	config = talloc(handle, struct gpfs_prefetch_config);
+	if (config == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		errno = ENOMEM;
+		return -1;
+	}
+
+	mask = lp_parm_const_string(SNUM(handle->conn), "gpfs_prefetch",
+				    "mask", "");
+
+	set_namearray(&config->namelist, mask);
+	config->size = lp_parm_int(SNUM(handle->conn), "gpfs_prefetch",
+				   "size", 1024);
+
+	/*
+	 * The size calculations in the core routines assume that
+	 * config->size is the size from the center to the border of
+	 * the prefetched area. So we need to multiply by 1024/2 here
+	 * to get the whole prefetch area in kilobytes.
+	 */
+	config->size *= 1024/2;
+
+	SMB_VFS_HANDLE_SET_DATA(handle, config, gpfs_prefetch_config_free,
+				struct gpfs_prefetch_config, goto fail);
+
+	return SMB_VFS_NEXT_CONNECT(handle, service, user);
+
+fail:
+	free_namearray(config->namelist);
+	TALLOC_FREE(config);
+	return -1;
+}
+
+/* VFS operations structure */
+
+static vfs_op_tuple gpfs_prefetch_op_tuples[] = {
+
+	{SMB_VFS_OP(gpfs_prefetch_open),	SMB_VFS_OP_OPEN,
+	 SMB_VFS_LAYER_TRANSPARENT },
+	{SMB_VFS_OP(gpfs_prefetch_pread),	SMB_VFS_OP_PREAD,
+	 SMB_VFS_LAYER_TRANSPARENT },
+	{SMB_VFS_OP(gpfs_prefetch_connect),	SMB_VFS_OP_CONNECT,
+	 SMB_VFS_LAYER_TRANSPARENT },
+
+        { SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP }
+};
+
+/*
+ * When done properly upstream (GPL issue resolved), change this
+ * routine name to vfs_gpfs_prefetch_init!!
+ */
+
+NTSTATUS init_samba_module(void);
+NTSTATUS init_samba_module(void)
+{
+	NTSTATUS status;
+
+	DEBUG(10, ("vfs_gpfs_prefetch_init called\n"));
+
+	status = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "gpfs_prefetch",
+				  gpfs_prefetch_op_tuples);
+	DEBUG(10, ("smb_register_vfs returned %s\n",
+		   nt_errstr(status)));
+
+	return status;
+}