Adding upstream version 2:4.17.12+dfsg.upstream/2%4.17.12+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 222 insertions, 0 deletions

diff --git a/source3/modules/vfs_prealloc.c b/source3/modules/vfs_prealloc.c
new file mode 100644
index 0000000..51e9ad0
--- /dev/null
+++ b/source3/modules/vfs_prealloc.c
@@ -0,0 +1,222 @@
+/*
+ * 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 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"
+#include "system/filesys.h"
+#include "smbd/smbd.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, off_t size)
+{
+	int err;
+	lock_type fl = {0};
+
+	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)
+{
+	int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
+
+	if (ret < 0) {
+		return ret;
+	}
+
+	module_debug = lp_parm_int(SNUM(handle->conn),
+					MODULE, "debug", 100);
+
+	return 0;
+}
+
+static int prealloc_openat(struct vfs_handle_struct* handle,
+			   const struct files_struct *dirfsp,
+			   const struct smb_filename *smb_fname,
+			   files_struct *fsp,
+			   const struct vfs_open_how *how)
+{
+	int fd;
+	off_t size = 0;
+	const char * dot;
+	char fext[10];
+
+	if (!(how->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(smb_fname->base_name, '.');
+	if (dot && *++dot) {
+		if (strlen(dot) < sizeof(fext)) {
+			bool ok;
+			strncpy(fext, dot, sizeof(fext));
+			ok = strlower_m(fext);
+			if (!ok);
+				goto normal_open;
+			}
+		}
+	}
+
+	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_OPENAT(handle, dirfsp, smb_fname, fsp, how);
+	if (fd < 0) {
+		return fd;
+	}
+
+	/* Preallocate 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 ((how->flags & O_CREAT) || (how->flags & O_TRUNC)) {
+		off_t * psize;
+
+		psize = VFS_ADD_FSP_EXTENSION(handle, fsp, off_t, NULL);
+		if (psize == NULL || *psize == -1) {
+			return fd;
+		}
+
+		DEBUG(module_debug,
+			("%s: preallocating %s (fd=%d) to %lld bytes\n",
+			    MODULE, smb_fname_str_dbg(smb_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, smb_fname_str_dbg(smb_fname)));
+	return SMB_VFS_NEXT_OPENAT(handle, dirfsp, smb_fname, fsp, how);
+}
+
+static int prealloc_ftruncate(vfs_handle_struct * handle,
+			files_struct *	fsp,
+			off_t	offset)
+{
+	off_t *psize;
+	int ret = SMB_VFS_NEXT_FTRUNCATE(handle, fsp, offset);
+
+	/* Maintain the allocated space even in the face of truncates. */
+	if ((psize = VFS_FETCH_FSP_EXTENSION(handle, fsp))) {
+		preallocate_space(fsp_get_io_fd(fsp), *psize);
+	}
+
+	return ret;
+}
+
+static struct vfs_fn_pointers prealloc_fns = {
+	.openat_fn = prealloc_openat,
+	.ftruncate_fn = prealloc_ftruncate,
+	.connect_fn = prealloc_connect,
+};
+
+static_decl_vfs;
+NTSTATUS vfs_prealloc_init(TALLOC_CTX *ctx)
+{
+	return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
+				MODULE, &prealloc_fns);
+}