[lvm-devel] LVM2 ./WHATS_NEW_DM libdm/libdm-common.c libdm ...
zkabelac at sourceware.org
zkabelac at sourceware.org
Mon Jan 9 12:26:16 UTC 2012
CVSROOT: /cvs/lvm2
Module name: LVM2
Changes by: zkabelac at sourceware.org 2012-01-09 12:26:15
Modified files:
. : WHATS_NEW_DM
libdm : libdm-common.c libdm-common.h
libdm/ioctl : libdm-iface.c
Log message:
Use sysfs to set/get of read-ahead
If we know major:minor number of device (which is known after resume) we will
try to use sysfs to set/get read ahead parameters of device.
This avoid potential problem of blocking commands like 'dmsetup info' awaiting
for device being usable for open/close - i.e. overfilled thin pool may block
such command.
Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/WHATS_NEW_DM.diff?cvsroot=lvm2&r1=1.526&r2=1.527
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/libdm/libdm-common.c.diff?cvsroot=lvm2&r1=1.129&r2=1.130
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/libdm/libdm-common.h.diff?cvsroot=lvm2&r1=1.9&r2=1.10
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/libdm/ioctl/libdm-iface.c.diff?cvsroot=lvm2&r1=1.130&r2=1.131
--- LVM2/WHATS_NEW_DM 2011/12/21 12:47:44 1.526
+++ LVM2/WHATS_NEW_DM 2012/01/09 12:26:14 1.527
@@ -1,5 +1,6 @@
Version 1.02.68 -
==================================
+ Use sysfs to set/get of read-ahead setting if possible.
Fix lvm2-monitor init script to use normalized output when using vgs.
Add test for max length (DM_MAX_TYPE_NAME) of target type name.
Include a copy of kernel DM documentation in doc/kernel.
--- LVM2/libdm/libdm-common.c 2011/12/18 21:56:03 1.129
+++ LVM2/libdm/libdm-common.c 2012/01/09 12:26:15 1.130
@@ -1,6 +1,6 @@
/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2012 Red Hat, Inc. All rights reserved.
*
* This file is part of the device-mapper userspace tools.
*
@@ -59,6 +59,7 @@
static char _dm_dir[PATH_MAX] = DEV_DIR DM_DIR;
static char _sysfs_dir[PATH_MAX] = "/sys/";
+static char _path0[PATH_MAX]; /* path buffer, safe 4kB on stack */
static int _verbose = 0;
static int _suspended_dev_counter = 0;
@@ -658,12 +659,53 @@
return fd;
}
-int get_dev_node_read_ahead(const char *dev_name, uint32_t *read_ahead)
+int get_dev_node_read_ahead(const char *dev_name, uint32_t major, uint32_t minor,
+ uint32_t *read_ahead)
{
+ char buf[24];
+ int len;
int r = 1;
int fd;
long read_ahead_long;
+ /*
+ * If we know the device number, use sysfs if we can.
+ * Otherwise use BLKRAGET ioctl.
+ */
+ if (*_sysfs_dir && major != 0) {
+ if (dm_snprintf(_path0, sizeof(_path0), "%sdev/block/%" PRIu32
+ ":%" PRIu32 "/bdi/read_ahead_kb", _sysfs_dir,
+ major, minor) < 0) {
+ log_error("Failed to build sysfs_path.");
+ return 0;
+ }
+
+ if ((fd = open(_path0, O_RDONLY, 0)) != -1) {
+ /* Reading from sysfs, expecting number\n */
+ if ((len = read(fd, buf, sizeof(buf))) < 1) {
+ log_sys_error("read", _path0);
+ r = 0;
+ } else {
+ buf[len] = 0; /* kill \n and ensure \0 */
+ *read_ahead = atoi(buf) * 2;
+ log_debug("%s (%d:%d): read ahead is %" PRIu32,
+ dev_name, major, minor, *read_ahead);
+ }
+
+ if (close(fd))
+ log_sys_debug("close", _path0);
+
+ return r;
+ }
+
+ log_sys_debug("open", _path0);
+ /* Fall back to use dev_name */
+ }
+
+ /*
+ * Open/close dev_name may block the process
+ * (i.e. overfilled thin pool volume)
+ */
if (!*dev_name) {
log_error("Empty device name passed to BLKRAGET");
return 0;
@@ -676,23 +718,64 @@
log_sys_error("BLKRAGET", dev_name);
*read_ahead = 0;
r = 0;
- } else {
+ } else {
*read_ahead = (uint32_t) read_ahead_long;
log_debug("%s: read ahead is %" PRIu32, dev_name, *read_ahead);
}
if (close(fd))
- stack;
+ log_sys_debug("close", dev_name);
return r;
}
-static int _set_read_ahead(const char *dev_name, uint32_t read_ahead)
+static int _set_read_ahead(const char *dev_name, uint32_t major, uint32_t minor,
+ uint32_t read_ahead)
{
+ char buf[24];
+ int len;
int r = 1;
int fd;
long read_ahead_long = (long) read_ahead;
+ log_debug("%s (%d:%d): Setting read ahead to %" PRIu32, dev_name,
+ major, minor, read_ahead);
+
+ /*
+ * If we know the device number, use sysfs if we can.
+ * Otherwise use BLKRASET ioctl. RA is set after resume.
+ */
+ if (*_sysfs_dir && major != 0) {
+ if (dm_snprintf(_path0, sizeof(_path0), "%sdev/block/%" PRIu32
+ ":%" PRIu32 "/bdi/read_ahead_kb",
+ _sysfs_dir, major, minor) < 0) {
+ log_error("Failed to build sysfs_path.");
+ return 0;
+ }
+
+ /* Sysfs is kB based, round up to kB */
+ if ((len = dm_snprintf(buf, sizeof(buf), "%" PRIu32,
+ (read_ahead + 1) / 2)) < 0) {
+ log_error("Failed to build size in kB.");
+ return 0;
+ }
+
+ if ((fd = open(_path0, O_WRONLY, 0)) != -1) {
+ if (write(fd, buf, len) < len) {
+ log_sys_error("write", _path0);
+ r = 0;
+ }
+
+ if (close(fd))
+ log_sys_debug("close", _path0);
+
+ return r;
+ }
+
+ log_sys_debug("open", _path0);
+ /* Fall back to use dev_name */
+ }
+
if (!*dev_name) {
log_error("Empty device name passed to BLKRAGET");
return 0;
@@ -701,21 +784,20 @@
if ((fd = _open_dev_node(dev_name)) < 0)
return_0;
- log_debug("%s: Setting read ahead to %" PRIu32, dev_name, read_ahead);
-
if (ioctl(fd, BLKRASET, read_ahead_long)) {
log_sys_error("BLKRASET", dev_name);
r = 0;
}
if (close(fd))
- stack;
+ log_sys_debug("close", dev_name);
return r;
}
-static int _set_dev_node_read_ahead(const char *dev_name, uint32_t read_ahead,
- uint32_t read_ahead_flags)
+static int _set_dev_node_read_ahead(const char *dev_name,
+ uint32_t major, uint32_t minor,
+ uint32_t read_ahead, uint32_t read_ahead_flags)
{
uint32_t current_read_ahead;
@@ -726,7 +808,7 @@
read_ahead = 0;
if (read_ahead_flags & DM_READ_AHEAD_MINIMUM_FLAG) {
- if (!get_dev_node_read_ahead(dev_name, ¤t_read_ahead))
+ if (!get_dev_node_read_ahead(dev_name, major, minor, ¤t_read_ahead))
return_0;
if (current_read_ahead > read_ahead) {
@@ -737,7 +819,7 @@
}
}
- return _set_read_ahead(dev_name, read_ahead);
+ return _set_read_ahead(dev_name, major, minor, read_ahead);
}
#else
@@ -749,8 +831,9 @@
return 1;
}
-static int _set_dev_node_read_ahead(const char *dev_name, uint32_t read_ahead,
- uint32_t read_ahead_flags)
+static int _set_dev_node_read_ahead(const char *dev_name,
+ uint32_t major, uint32_t minor,
+ uint32_t read_ahead, uint32_t read_ahead_flags)
{
return 1;
}
@@ -778,8 +861,8 @@
case NODE_RENAME:
return _rename_dev_node(old_name, dev_name, warn_if_udev_failed);
case NODE_READ_AHEAD:
- return _set_dev_node_read_ahead(dev_name, read_ahead,
- read_ahead_flags);
+ return _set_dev_node_read_ahead(dev_name, major, minor,
+ read_ahead, read_ahead_flags);
default:
; /* NOTREACHED */
}
@@ -993,13 +1076,14 @@
0, 0, "", 0, 0, check_udev, rely_on_udev);
}
-int set_dev_node_read_ahead(const char *dev_name, uint32_t read_ahead,
- uint32_t read_ahead_flags)
+int set_dev_node_read_ahead(const char *dev_name,
+ uint32_t major, uint32_t minor,
+ uint32_t read_ahead, uint32_t read_ahead_flags)
{
if (read_ahead == DM_READ_AHEAD_AUTO)
return 1;
- return _stack_node_op(NODE_READ_AHEAD, dev_name, 0, 0, 0, 0,
+ return _stack_node_op(NODE_READ_AHEAD, dev_name, major, minor, 0, 0,
0, "", read_ahead, read_ahead_flags, 0, 0);
}
--- LVM2/libdm/libdm-common.h 2011/06/27 21:43:59 1.9
+++ LVM2/libdm/libdm-common.h 2012/01/09 12:26:15 1.10
@@ -1,6 +1,6 @@
/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2012 Red Hat, Inc. All rights reserved.
*
* This file is part of the device-mapper userspace tools.
*
@@ -27,9 +27,10 @@
int rm_dev_node(const char *dev_name, int check_udev, unsigned rely_on_udev);
int rename_dev_node(const char *old_name, const char *new_name,
int check_udev, unsigned rely_on_udev);
-int get_dev_node_read_ahead(const char *dev_name, uint32_t *read_ahead);
-int set_dev_node_read_ahead(const char *dev_name, uint32_t read_ahead,
- uint32_t read_ahead_flags);
+int get_dev_node_read_ahead(const char *dev_name, uint32_t major, uint32_t minor,
+ uint32_t *read_ahead);
+int set_dev_node_read_ahead(const char *dev_name, uint32_t major, uint32_t minor,
+ uint32_t read_ahead, uint32_t read_ahead_flags);
void update_devs(void);
void selinux_release(void);
--- LVM2/libdm/ioctl/libdm-iface.c 2011/11/30 02:02:12 1.130
+++ LVM2/libdm/ioctl/libdm-iface.c 2012/01/09 12:26:15 1.131
@@ -1,6 +1,6 @@
/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004-2011 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2012 Red Hat, Inc. All rights reserved.
*
* This file is part of the device-mapper userspace tools.
*
@@ -665,7 +665,8 @@
return 0;
}
- return get_dev_node_read_ahead(dev_name, read_ahead);
+ return get_dev_node_read_ahead(dev_name, MAJOR(dmt->dmi.v4->dev),
+ MINOR(dmt->dmi.v4->dev), read_ahead);
}
const char *dm_task_get_name(const struct dm_task *dmt)
@@ -1818,8 +1819,9 @@
MINOR(dmi->dev), dmt->uid, dmt->gid,
dmt->mode, check_udev, rely_on_udev);
/* FIXME Kernel needs to fill in dmi->name */
- set_dev_node_read_ahead(dmt->dev_name, dmt->read_ahead,
- dmt->read_ahead_flags);
+ set_dev_node_read_ahead(dmt->dev_name,
+ MAJOR(dmi->dev), MINOR(dmi->dev),
+ dmt->read_ahead, dmt->read_ahead_flags);
break;
case DM_DEVICE_MKNODES:
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