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mirror of git://sourceware.org/git/lvm2.git synced 2024-11-06 08:26:59 +03:00

daemons: add dmfilemapd

Add a daemon that can be launched to monitor a group of regions
corresponding to the extents of a file, and to update the regions as the
file's allocation changes.

The daemon is intended to be started from a library interface, but can
also be run from the command line:

  dmfilemapd <fd> <group_id> <path> <mode> [<foreground>[<log_level>]]

Where fd is a file descriptor open on the mapped file, group_id is the
group identifier of the mapped group and mode is either "inode" or
"path". E.g.:

  # dmfilemapd 3 0 vm.img inode 1 3 3<vm.img
  ...

If foreground is non-zero, the daemon will not fork to run in the
background. If verbose is non-zero, libdm and daemon log messages will
be printed.

It is possible for the group identifier to change when regions are
re-mapped: this occurs when the group leader is deleted (regroup=1 in
dm_stats_update_regions_from_fd()), and another region is created before
the daemon has a chance to recreate the leader region.

The operation is inherently racey since there is currently no way to
atomically move or resize a dm_stats region while retaining its
region_id.

Detect this condition and update the group_id value stored in the
filemap monitor.

A function is also provided in the the stats API to launch the filemap
monitoring daemon:

  int dm_stats_start_filemapd(int fd, uint64_t group_id, const char *path,
                              dm_filemapd_mode_t mode, unsigned foreground,
                              unsigned verbose);

This carries out the first fork and execs dmfilemapd with the arguments
specified.

A dm_filemapd_mode_t value is specified by the mode argument: either
DM_FILEMAPD_FOLLOW_INODE, or DM_FILEMAPD_FOLLOW_PATH. A helper function,
dm_filemapd_mode_from_string(), is provided to parse a string containing
a valid mode name into the appropriate dm_filemapd_mode_t value.
This commit is contained in:
Bryn M. Reeves 2016-12-15 20:10:27 +00:00
parent c98868181f
commit 8b78982297
10 changed files with 1147 additions and 2 deletions

42
configure vendored
View File

@ -702,6 +702,7 @@ BLKDEACTIVATE
FSADM
ELDFLAGS
DM_LIB_PATCHLEVEL
DMFILEMAPD
DMEVENTD_PATH
DMEVENTD
DL_LIBS
@ -737,6 +738,7 @@ CLDNOWHOLEARCHIVE
CLDFLAGS
CACHE
BUILD_NOTIFYDBUS
BUILD_DMFILEMAPD
BUILD_LOCKDDLM
BUILD_LOCKDSANLOCK
BUILD_LVMLOCKD
@ -960,6 +962,7 @@ enable_use_lvmetad
with_lvmetad_pidfile
enable_use_lvmpolld
with_lvmpolld_pidfile
enable_dmfilemapd
enable_notify_dbus
enable_blkid_wiping
enable_udev_systemd_background_jobs
@ -1694,6 +1697,7 @@ Optional Features:
--disable-use-lvmlockd disable usage of LVM lock daemon
--disable-use-lvmetad disable usage of LVM Metadata Daemon
--disable-use-lvmpolld disable usage of LVM Poll Daemon
--enable-dmfilemapd enable the dmstats filemap daemon
--enable-notify-dbus enable LVM notification using dbus
--disable-blkid_wiping disable libblkid detection of signatures when wiping
and use native code instead
@ -12074,6 +12078,21 @@ cat >>confdefs.h <<_ACEOF
_ACEOF
################################################################################
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to build dmfilemapd" >&5
$as_echo_n "checking whether to build dmfilemapd... " >&6; }
# Check whether --enable-dmfilemapd was given.
if test "${enable_dmfilemapd+set}" = set; then :
enableval=$enable_dmfilemapd; DMFILEMAPD=$enableval
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $DMFILEMAPD" >&5
$as_echo "$DMFILEMAPD" >&6; }
BUILD_DMFILEMAPD=$DMFILEMAPD
$as_echo "#define DMFILEMAPD 1" >>confdefs.h
################################################################################
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to build notifydbus" >&5
$as_echo_n "checking whether to build notifydbus... " >&6; }
@ -15123,6 +15142,24 @@ done
fi
if test "$DMFILEMAPD" = yes; then
for ac_header in sys/inotify.h
do :
ac_fn_c_check_header_mongrel "$LINENO" "sys/inotify.h" "ac_cv_header_sys_inotify_h" "$ac_includes_default"
if test "x$ac_cv_header_sys_inotify_h" = xyes; then :
cat >>confdefs.h <<_ACEOF
#define HAVE_SYS_INOTIFY_H 1
_ACEOF
else
hard_bailout
fi
done
fi
################################################################################
if test -n "$ac_tool_prefix"; then
# Extract the first word of "${ac_tool_prefix}modprobe", so it can be a program name with args.
@ -15582,11 +15619,13 @@ LVM_LIBAPI=`echo "$VER" | $AWK -F '[()]' '{print $2}'`
################################################################################
ac_config_files="$ac_config_files Makefile make.tmpl daemons/Makefile daemons/clvmd/Makefile daemons/cmirrord/Makefile daemons/dmeventd/Makefile daemons/dmeventd/libdevmapper-event.pc daemons/dmeventd/plugins/Makefile daemons/dmeventd/plugins/lvm2/Makefile daemons/dmeventd/plugins/raid/Makefile daemons/dmeventd/plugins/mirror/Makefile daemons/dmeventd/plugins/snapshot/Makefile daemons/dmeventd/plugins/thin/Makefile daemons/lvmdbusd/Makefile daemons/lvmdbusd/path.py daemons/lvmetad/Makefile daemons/lvmpolld/Makefile daemons/lvmlockd/Makefile conf/Makefile conf/example.conf conf/lvmlocal.conf conf/command_profile_template.profile conf/metadata_profile_template.profile include/.symlinks include/Makefile lib/Makefile lib/format1/Makefile lib/format_pool/Makefile lib/locking/Makefile lib/mirror/Makefile lib/replicator/Makefile include/lvm-version.h lib/raid/Makefile lib/snapshot/Makefile lib/thin/Makefile lib/cache_segtype/Makefile libdaemon/Makefile libdaemon/client/Makefile libdaemon/server/Makefile libdm/Makefile libdm/libdevmapper.pc liblvm/Makefile liblvm/liblvm2app.pc man/Makefile po/Makefile python/Makefile python/setup.py scripts/blkdeactivate.sh scripts/blk_availability_init_red_hat scripts/blk_availability_systemd_red_hat.service scripts/clvmd_init_red_hat scripts/cmirrord_init_red_hat scripts/com.redhat.lvmdbus1.service scripts/dm_event_systemd_red_hat.service scripts/dm_event_systemd_red_hat.socket scripts/lvm2_cluster_activation_red_hat.sh scripts/lvm2_cluster_activation_systemd_red_hat.service scripts/lvm2_clvmd_systemd_red_hat.service scripts/lvm2_cmirrord_systemd_red_hat.service scripts/lvm2_lvmdbusd_systemd_red_hat.service scripts/lvm2_lvmetad_init_red_hat scripts/lvm2_lvmetad_systemd_red_hat.service scripts/lvm2_lvmetad_systemd_red_hat.socket scripts/lvm2_lvmpolld_init_red_hat scripts/lvm2_lvmpolld_systemd_red_hat.service scripts/lvm2_lvmpolld_systemd_red_hat.socket scripts/lvm2_lvmlockd_systemd_red_hat.service scripts/lvm2_lvmlocking_systemd_red_hat.service scripts/lvm2_monitoring_init_red_hat scripts/lvm2_monitoring_systemd_red_hat.service scripts/lvm2_pvscan_systemd_red_hat@.service scripts/lvm2_tmpfiles_red_hat.conf scripts/lvmdump.sh scripts/Makefile test/Makefile test/api/Makefile test/unit/Makefile tools/Makefile udev/Makefile unit-tests/datastruct/Makefile unit-tests/regex/Makefile unit-tests/mm/Makefile"
ac_config_files="$ac_config_files Makefile make.tmpl daemons/Makefile daemons/clvmd/Makefile daemons/cmirrord/Makefile daemons/dmeventd/Makefile daemons/dmeventd/libdevmapper-event.pc daemons/dmeventd/plugins/Makefile daemons/dmeventd/plugins/lvm2/Makefile daemons/dmeventd/plugins/raid/Makefile daemons/dmeventd/plugins/mirror/Makefile daemons/dmeventd/plugins/snapshot/Makefile daemons/dmeventd/plugins/thin/Makefile daemons/dmfilemapd/Makefile daemons/lvmdbusd/Makefile daemons/lvmdbusd/path.py daemons/lvmetad/Makefile daemons/lvmpolld/Makefile daemons/lvmlockd/Makefile conf/Makefile conf/example.conf conf/lvmlocal.conf conf/command_profile_template.profile conf/metadata_profile_template.profile include/.symlinks include/Makefile lib/Makefile lib/format1/Makefile lib/format_pool/Makefile lib/locking/Makefile lib/mirror/Makefile lib/replicator/Makefile include/lvm-version.h lib/raid/Makefile lib/snapshot/Makefile lib/thin/Makefile lib/cache_segtype/Makefile libdaemon/Makefile libdaemon/client/Makefile libdaemon/server/Makefile libdm/Makefile libdm/libdevmapper.pc liblvm/Makefile liblvm/liblvm2app.pc man/Makefile po/Makefile python/Makefile python/setup.py scripts/blkdeactivate.sh scripts/blk_availability_init_red_hat scripts/blk_availability_systemd_red_hat.service scripts/clvmd_init_red_hat scripts/cmirrord_init_red_hat scripts/com.redhat.lvmdbus1.service scripts/dm_event_systemd_red_hat.service scripts/dm_event_systemd_red_hat.socket scripts/lvm2_cluster_activation_red_hat.sh scripts/lvm2_cluster_activation_systemd_red_hat.service scripts/lvm2_clvmd_systemd_red_hat.service scripts/lvm2_cmirrord_systemd_red_hat.service scripts/lvm2_lvmdbusd_systemd_red_hat.service scripts/lvm2_lvmetad_init_red_hat scripts/lvm2_lvmetad_systemd_red_hat.service scripts/lvm2_lvmetad_systemd_red_hat.socket scripts/lvm2_lvmpolld_init_red_hat scripts/lvm2_lvmpolld_systemd_red_hat.service scripts/lvm2_lvmpolld_systemd_red_hat.socket scripts/lvm2_lvmlockd_systemd_red_hat.service scripts/lvm2_lvmlocking_systemd_red_hat.service scripts/lvm2_monitoring_init_red_hat scripts/lvm2_monitoring_systemd_red_hat.service scripts/lvm2_pvscan_systemd_red_hat@.service scripts/lvm2_tmpfiles_red_hat.conf scripts/lvmdump.sh scripts/Makefile test/Makefile test/api/Makefile test/unit/Makefile tools/Makefile udev/Makefile unit-tests/datastruct/Makefile unit-tests/regex/Makefile unit-tests/mm/Makefile"
cat >confcache <<\_ACEOF
# This file is a shell script that caches the results of configure
@ -16294,6 +16333,7 @@ do
"daemons/dmeventd/plugins/mirror/Makefile") CONFIG_FILES="$CONFIG_FILES daemons/dmeventd/plugins/mirror/Makefile" ;;
"daemons/dmeventd/plugins/snapshot/Makefile") CONFIG_FILES="$CONFIG_FILES daemons/dmeventd/plugins/snapshot/Makefile" ;;
"daemons/dmeventd/plugins/thin/Makefile") CONFIG_FILES="$CONFIG_FILES daemons/dmeventd/plugins/thin/Makefile" ;;
"daemons/dmfilemapd/Makefile") CONFIG_FILES="$CONFIG_FILES daemons/dmfilemapd/Makefile" ;;
"daemons/lvmdbusd/Makefile") CONFIG_FILES="$CONFIG_FILES daemons/lvmdbusd/Makefile" ;;
"daemons/lvmdbusd/path.py") CONFIG_FILES="$CONFIG_FILES daemons/lvmdbusd/path.py" ;;
"daemons/lvmetad/Makefile") CONFIG_FILES="$CONFIG_FILES daemons/lvmetad/Makefile" ;;

View File

@ -1271,6 +1271,16 @@ fi
AC_DEFINE_UNQUOTED(DEFAULT_USE_LVMPOLLD, [$DEFAULT_USE_LVMPOLLD],
[Use lvmpolld by default.])
################################################################################
dnl -- Check dmfilemapd
AC_MSG_CHECKING(whether to build dmfilemapd)
AC_ARG_ENABLE(dmfilemapd, AC_HELP_STRING([--enable-dmfilemapd],
[enable the dmstats filemap daemon]),
DMFILEMAPD=$enableval)
AC_MSG_RESULT($DMFILEMAPD)
BUILD_DMFILEMAPD=$DMFILEMAPD
AC_DEFINE([DMFILEMAPD], 1, [Define to 1 to enable the device-mapper filemap daemon.])
################################################################################
dnl -- Build notifydbus
AC_MSG_CHECKING(whether to build notifydbus)
@ -1855,6 +1865,10 @@ if test "$UDEV_SYNC" = yes; then
AC_CHECK_HEADERS(sys/ipc.h sys/sem.h,,hard_bailout)
fi
if test "$DMFILEMAPD" = yes; then
AC_CHECK_HEADERS([sys/inotify.h],,hard_bailout)
fi
################################################################################
AC_PATH_TOOL(MODPROBE_CMD, modprobe)
@ -1994,6 +2008,7 @@ AC_SUBST(BUILD_LVMPOLLD)
AC_SUBST(BUILD_LVMLOCKD)
AC_SUBST(BUILD_LOCKDSANLOCK)
AC_SUBST(BUILD_LOCKDDLM)
AC_SUBST(BUILD_DMFILEMAPD)
AC_SUBST(BUILD_NOTIFYDBUS)
AC_SUBST(CACHE)
AC_SUBST(CFLAGS)
@ -2043,6 +2058,7 @@ AC_SUBST(DLM_LIBS)
AC_SUBST(DL_LIBS)
AC_SUBST(DMEVENTD)
AC_SUBST(DMEVENTD_PATH)
AC_SUBST(DMFILEMAPD)
AC_SUBST(DM_LIB_PATCHLEVEL)
AC_SUBST(ELDFLAGS)
AC_SUBST(FSADM)
@ -2158,6 +2174,7 @@ daemons/dmeventd/plugins/raid/Makefile
daemons/dmeventd/plugins/mirror/Makefile
daemons/dmeventd/plugins/snapshot/Makefile
daemons/dmeventd/plugins/thin/Makefile
daemons/dmfilemapd/Makefile
daemons/lvmdbusd/Makefile
daemons/lvmdbusd/path.py
daemons/lvmetad/Makefile

View File

@ -48,8 +48,12 @@ ifeq ("@BUILD_LVMDBUSD@", "yes")
SUBDIRS += lvmdbusd
endif
ifeq ("@BUILD_DMFILEMAPD@", "yes")
SUBDIRS += dmfilemapd
endif
ifeq ($(MAKECMDGOALS),distclean)
SUBDIRS = clvmd cmirrord dmeventd lvmetad lvmpolld lvmlockd lvmdbusd
SUBDIRS = clvmd cmirrord dmeventd lvmetad lvmpolld lvmlockd lvmdbusd dmfilemapd
endif
include $(top_builddir)/make.tmpl

1
daemons/dmfilemapd/.gitignore vendored Normal file
View File

@ -0,0 +1 @@
dmfilemapd

View File

@ -0,0 +1,69 @@
#
# Copyright (C) 2016 Red Hat, Inc. All rights reserved.
#
# This file is part of the device-mapper userspace tools.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions
# of the GNU Lesser General Public License v.2.1.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
srcdir = @srcdir@
top_srcdir = @top_srcdir@
top_builddir = @top_builddir@
SOURCES = dmfilemapd.c
TARGETS = dmfilemapd
.PHONY: install_dmeventd install_dmeventd_static
INSTALL_DMFILEMAPD_TARGETS = install_dmfilemapd_dynamic
CLEAN_TARGETS = dmfilemapd.static
CFLOW_LIST = $(SOURCES)
CFLOW_LIST_TARGET = $(LIB_NAME).cflow
CFLOW_TARGET = dmfilemapd
include $(top_builddir)/make.tmpl
all: device-mapper
device-mapper: $(TARGETS)
LIBS += -ldevmapper
LVMLIBS += -ldevmapper-event $(PTHREAD_LIBS)
CFLAGS_dmeventd.o += $(EXTRA_EXEC_CFLAGS)
dmfilemapd: $(LIB_SHARED) dmfilemapd.o
$(CC) $(CFLAGS) $(LDFLAGS) $(EXTRA_EXEC_LDFLAGS) $(ELDFLAGS) -L. -o $@ dmfilemapd.o \
$(DL_LIBS) $(LVMLIBS) $(LIBS) -rdynamic
dmfilemapd.static: $(LIB_STATIC) dmfilemapd.o $(interfacebuilddir)/libdevmapper.a
$(CC) $(CFLAGS) $(LDFLAGS) $(ELDFLAGS) -static -L. -L$(interfacebuilddir) -o $@ \
dmfilemapd.o $(DL_LIBS) $(LVMLIBS) $(LIBS) $(STATIC_LIBS)
ifneq ("$(CFLOW_CMD)", "")
CFLOW_SOURCES = $(addprefix $(srcdir)/, $(SOURCES))
-include $(top_builddir)/libdm/libdevmapper.cflow
-include $(top_builddir)/lib/liblvm-internal.cflow
-include $(top_builddir)/lib/liblvm2cmd.cflow
-include $(top_builddir)/daemons/dmfilemapd/$(LIB_NAME).cflow
endif
install_dmfilemapd_dynamic: dmfilemapd
$(INSTALL_PROGRAM) -D $< $(sbindir)/$(<F)
install_dmfilemapd_static: dmfilemapd.static
$(INSTALL_PROGRAM) -D $< $(staticdir)/$(<F)
install_dmfilemapd: $(INSTALL_DMEVENTD_TARGETS)
install: install_dmfilemapd
install_device-mapper: install_dmfilemapd

View File

@ -0,0 +1,791 @@
/*
* Copyright (C) 2016 Red Hat, Inc. All rights reserved.
*
* This file is part of the device-mapper userspace tools.
*
* It includes tree drawing code based on pstree: http://psmisc.sourceforge.net/
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "tool.h"
#include "dm-logging.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/inotify.h>
#include <dirent.h>
#include <ctype.h>
#ifdef __linux__
# include "kdev_t.h"
#else
# define MAJOR(x) major((x))
# define MINOR(x) minor((x))
# define MKDEV(x,y) makedev((x),(y))
#endif
/* limit to two updates/sec */
#define FILEMAPD_WAIT_USECS 500000
/* how long to wait for unlinked files */
#define FILEMAPD_NOFILE_WAIT_USECS 100000
#define FILEMAPD_NOFILE_WAIT_TRIES 10
struct filemap_monitor {
dm_filemapd_mode_t mode;
const char *program_id;
uint64_t group_id;
char *path;
int fd;
int inotify_fd;
int inotify_watch_fd;
/* monitoring heuristics */
int64_t blocks; /* allocated blocks, from stat.st_blocks */
int64_t nr_regions;
int deleted;
};
static int _foreground;
static int _verbose;
const char *const _usage = "dmfilemapd <fd> <group_id> <path> <mode> "
"[<foreground>[<log_level>]]";
/*
* Daemon logging. By default, all messages are thrown away: messages
* are only written to the terminal if the daemon is run in the foreground.
*/
__attribute__((format(printf, 5, 0)))
static void _dmfilemapd_log_line(int level,
const char *file __attribute__((unused)),
int line __attribute__((unused)),
int dm_errno_or_class,
const char *f, va_list ap)
{
static int _abort_on_internal_errors = -1;
FILE *out = log_stderr(level) ? stderr : stdout;
level = log_level(level);
if (level <= _LOG_WARN || _verbose) {
if (level < _LOG_WARN)
out = stderr;
vfprintf(out, f, ap);
fputc('\n', out);
}
if (_abort_on_internal_errors < 0)
/* Set when env DM_ABORT_ON_INTERNAL_ERRORS is not "0" */
_abort_on_internal_errors =
strcmp(getenv("DM_ABORT_ON_INTERNAL_ERRORS") ? : "0", "0");
if (_abort_on_internal_errors &&
!strncmp(f, INTERNAL_ERROR, sizeof(INTERNAL_ERROR) - 1))
abort();
}
__attribute__((format(printf, 5, 6)))
static void _dmfilemapd_log_with_errno(int level,
const char *file, int line,
int dm_errno_or_class,
const char *f, ...)
{
va_list ap;
va_start(ap, f);
_dmfilemapd_log_line(level, file, line, dm_errno_or_class, f, ap);
va_end(ap);
}
/*
* Only used for reporting errors before daemonise().
*/
__attribute__((format(printf, 1, 2)))
static void _early_log(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
fputc('\n', stderr);
va_end(ap);
}
static void _setup_logging(void)
{
dm_log_init_verbose(_verbose - 1);
dm_log_with_errno_init(_dmfilemapd_log_with_errno);
}
#define PROC_FD_DELETED_STR "(deleted)"
/*
* Scan the /proc/<pid>/fd directory for pid and check for an fd
* symlink whose contents match path.
*/
static int _is_open_in_pid(pid_t pid, const char *path)
{
char deleted_path[PATH_MAX + sizeof(PROC_FD_DELETED_STR)];
struct dirent *pid_dp = NULL;
char path_buf[PATH_MAX];
char link_buf[PATH_MAX];
DIR *pid_d = NULL;
ssize_t len;
if (pid == getpid())
return 0;
if (dm_snprintf(path_buf, sizeof(path_buf), "/proc/%d/fd", pid) < 0) {
log_error("Could not format pid path.");
goto bad;
}
/*
* Test for the kernel 'file (deleted)' form when scanning.
*/
if (dm_snprintf(deleted_path, sizeof(deleted_path), "%s %s",
path, PROC_FD_DELETED_STR) < 0) {
log_error("Could not format check path.");
}
pid_d = opendir(path_buf);
if (!pid_d) {
log_error("Could not open proc path: %s.", path_buf);
goto bad;
}
while ((pid_dp = readdir(pid_d)) != NULL) {
if (pid_dp->d_name[0] == '.')
continue;
if ((len = readlinkat(dirfd(pid_d), pid_dp->d_name, link_buf,
sizeof(link_buf))) < 0) {
log_error("readlink failed for /proc/%d/fd/.", pid);
goto bad;
}
link_buf[len] = '\0';
if (!strcmp(deleted_path, link_buf)) {
closedir(pid_d);
return 1;
}
}
bad:
closedir(pid_d);
return 0;
}
/*
* Attempt to determine whether a file is open by any process by
* scanning symbolic links in /proc/<pid>/fd.
*
* This is a heuristic since it cannot guarantee to detect brief
* access in all cases: a process that opens and then closes the
* file rapidly may never be seen by the scan.
*
* The method will also give false-positives if a process exists
* that has a deleted file open that had the same path, but a
* different inode number, to the file being monitored.
*
* For this reason the daemon only uses _is_open() for unlinked
* files when the mode is DM_FILEMAPD_FOLLOW_INODE, since these
* files can no longer be newly opened by processes.
*
* In this situation !is_open(path) provides an indication that
* the daemon should shut down: the file has been unlinked from
* the file system and we appear to hold the final reference.
*/
static int _is_open(const char *path)
{
struct dirent *proc_dp = NULL;
DIR *proc_d = NULL;
pid_t pid;
proc_d = opendir("/proc");
if (!proc_d)
return 0;
while ((proc_dp = readdir(proc_d)) != NULL) {
if (!isdigit(proc_dp->d_name[0]))
continue;
pid = strtol(proc_dp->d_name, NULL, 10);
if (!pid)
continue;
if (_is_open_in_pid(pid, path)) {
closedir(proc_d);
return 1;
}
}
closedir(proc_d);
return 0;
}
static void _filemap_monitor_wait(uint64_t usecs)
{
if (_verbose) {
if (usecs == FILEMAPD_WAIT_USECS)
log_very_verbose("Waiting for check interval");
if (usecs == FILEMAPD_NOFILE_WAIT_USECS)
log_very_verbose("Waiting for unlinked path");
}
usleep((useconds_t) usecs);
}
static int _parse_args(int argc, char **argv, struct filemap_monitor *fm)
{
char *endptr;
/* we don't care what is in argv[0]. */
argc--;
argv++;
if (argc < 5) {
_early_log("Wrong number of arguments.");
_early_log("usage: %s", _usage);
return 1;
}
memset(fm, 0, sizeof(*fm));
/*
* We don't know the true nr_regions at daemon start time,
* and it is not worth a dm_stats_list()/group walk to count:
* we can assume that there is at least one region or the
* daemon would not have been started.
*
* A correct value will be obtained following the first update
* of the group's regions.
*/
fm->nr_regions = 1;
/* parse <fd> */
fm->fd = strtol(argv[0], &endptr, 10);
if (*endptr) {
_early_log("Could not parse file descriptor: %s", argv[0]);
return 0;
}
argc--;
argv++;
/* parse <group_id> */
fm->group_id = strtoull(argv[0], &endptr, 10);
if (*endptr) {
_early_log("Could not parse group identifier: %s", argv[0]);
return 0;
}
argc--;
argv++;
/* parse <path> */
if (!argv[0] || !strlen(argv[0])) {
_early_log("Path argument is required.");
return 0;
}
fm->path = dm_strdup(argv[0]);
if (!fm->path) {
_early_log("Could not allocate memory for path argument.");
return 0;
}
argc--;
argv++;
/* parse <mode> */
if (!argv[0] || !strlen(argv[0])) {
_early_log("Mode argument is required.");
return 0;
}
fm->mode = dm_filemapd_mode_from_string(argv[0]);
if (fm->mode == DM_FILEMAPD_FOLLOW_NONE)
return 0;
argc--;
argv++;
/* parse [<foreground>[<verbose>]] */
if (argc) {
_foreground = strtol(argv[0], &endptr, 10);
if (*endptr) {
_early_log("Could not parse debug argument: %s.",
argv[0]);
return 0;
}
argc--;
argv++;
if (argc) {
_verbose = strtol(argv[0], &endptr, 10);
if (*endptr) {
_early_log("Could not parse verbose "
"argument: %s", argv[0]);
return 0;
}
if (_verbose < 0 || _verbose > 3) {
_early_log("Verbose argument out of range: %d.",
_verbose);
return 0;
}
}
}
return 1;
}
static int _filemap_fd_check_changed(struct filemap_monitor *fm)
{
int64_t blocks, old_blocks;
struct stat buf;
if (fm->fd < 0) {
log_error("Filemap fd is not open.");
return -1;
}
if (fstat(fm->fd, &buf)) {
log_error("Failed to fstat filemap file descriptor.");
return -1;
}
blocks = buf.st_blocks;
/* first check? */
if (fm->blocks < 0)
old_blocks = buf.st_blocks;
else
old_blocks = fm->blocks;
fm->blocks = blocks;
return (fm->blocks != old_blocks);
}
static void _filemap_monitor_close_fd(struct filemap_monitor *fm)
{
if (close(fm->fd))
log_error("Error closing file descriptor.");
fm->fd = -1;
}
static void _filemap_monitor_end_notify(struct filemap_monitor *fm)
{
inotify_rm_watch(fm->inotify_fd, fm->inotify_watch_fd);
}
static int _filemap_monitor_set_notify(struct filemap_monitor *fm)
{
int inotify_fd, watch_fd;
/*
* Set IN_NONBLOCK since we do not want to block in event read()
* calls. Do not set IN_CLOEXEC as dmfilemapd is single-threaded
* and does not fork or exec.
*/
if ((inotify_fd = inotify_init1(IN_NONBLOCK)) < 0) {
_early_log("Failed to initialise inotify.");
return 0;
}
if ((watch_fd = inotify_add_watch(inotify_fd, fm->path,
IN_MODIFY | IN_DELETE_SELF)) < 0) {
_early_log("Failed to add inotify watch.");
return 0;
}
fm->inotify_fd = inotify_fd;
fm->inotify_watch_fd = watch_fd;
return 1;
}
static int _filemap_monitor_reopen_fd(struct filemap_monitor *fm)
{
int tries = FILEMAPD_NOFILE_WAIT_TRIES;
/*
* In DM_FILEMAPD_FOLLOW_PATH mode, inotify watches must be
* re-established whenever the file at the watched path is
* changed.
*
* FIXME: stat file and skip if inode is unchanged.
*/
if (fm->fd > 0)
log_error("Filemap file descriptor already open.");
while ((fm->fd < 0) && --tries)
if (((fm->fd = open(fm->path, O_RDONLY)) < 0) && tries)
_filemap_monitor_wait(FILEMAPD_NOFILE_WAIT_USECS);
if (!tries && (fm->fd < 0)) {
log_error("Could not re-open file descriptor.");
return 0;
}
return _filemap_monitor_set_notify(fm);
}
static int _filemap_monitor_get_events(struct filemap_monitor *fm)
{
/* alignment as per man(7) inotify */
char buf[sizeof(struct inotify_event) + NAME_MAX + 1]
__attribute__ ((aligned(__alignof__(struct inotify_event))));
struct inotify_event *event;
int check = 0;
ssize_t len;
char *ptr;
/*
* Close the file descriptor for the file being monitored here
* when mode=path: this will allow the inode to be de-allocated,
* and an IN_DELETE_SELF event generated in the case that the
* daemon is holding the last open reference to the file.
*/
if (fm->mode == DM_FILEMAPD_FOLLOW_PATH) {
_filemap_monitor_end_notify(fm);
_filemap_monitor_close_fd(fm);
}
len = read(fm->inotify_fd, (void *) &buf, sizeof(buf));
/* no events to read? */
if (len < 0 && (errno == EAGAIN))
goto out;
/* interrupted by signal? */
if (len < 0 && (errno == EINTR))
goto out;
if (len < 0)
return -1;
if (!len)
goto out;
for (ptr = buf; ptr < buf + len; ptr += sizeof(*event) + event->len) {
event = (struct inotify_event *) ptr;
if (event->mask & IN_DELETE_SELF)
fm->deleted = 1;
if (event->mask & IN_MODIFY)
check = 1;
/*
* Event IN_IGNORED is generated when a file has been deleted
* and IN_DELETE_SELF generated, and indicates that the file
* watch has been automatically removed.
*
* This can only happen for the DM_FILEMAPD_FOLLOW_PATH mode,
* since inotify IN_DELETE events are generated at the time
* the inode is destroyed: DM_FILEMAPD_FOLLOW_INODE will hold
* the file descriptor open, meaning that the event will not
* be generated until after the daemon closes the file.
*
* The event is ignored here since inotify monitoring will
* be reestablished (or the daemon will terminate) following
* deletion of a DM_FILEMAPD_FOLLOW_PATH monitored file.
*/
if (event->mask & IN_IGNORED)
log_very_verbose("Inotify watch removed: IN_IGNORED "
"in event->mask");
}
out:
/*
* Re-open file descriptor if required and log disposition.
*/
if (fm->mode == DM_FILEMAPD_FOLLOW_PATH)
if (!_filemap_monitor_reopen_fd(fm))
return -1;
log_very_verbose("exiting _filemap_monitor_get_events() with "
"deleted=%d, check=%d", fm->deleted, check);
return check;
}
static void _filemap_monitor_destroy(struct filemap_monitor *fm)
{
if (fm->fd > 0) {
_filemap_monitor_end_notify(fm);
_filemap_monitor_close_fd(fm);
}
dm_free(fm->program_id);
}
static int _filemap_monitor_check_same_file(int fd1, int fd2)
{
struct stat buf1, buf2;
if ((fd1 < 0) || (fd2 < 0))
return 0;
if (fstat(fd1, &buf1)) {
log_error("Failed to fstat file descriptor %d", fd1);
return -1;
}
if (fstat(fd2, &buf2)) {
log_error("Failed to fstat file descriptor %d", fd2);
return -1;
}
return ((buf1.st_dev == buf2.st_dev) && (buf1.st_ino == buf2.st_ino));
}
static int _filemap_monitor_check_file_unlinked(struct filemap_monitor *fm)
{
char path_buf[PATH_MAX];
char link_buf[PATH_MAX];
int same, fd, len;
fm->deleted = 0;
if ((fd = open(fm->path, O_RDONLY)) < 0)
goto check_unlinked;
if ((same = _filemap_monitor_check_same_file(fm->fd, fd)) < 0)
return 0;
if (close(fd))
log_error("Error closing fd %d", fd);
if (same)
return 1;
check_unlinked:
/*
* The file has been unlinked from its original location: test
* whether it is still reachable in the filesystem, or if it is
* unlinked and anonymous.
*/
if (dm_snprintf(path_buf, sizeof(path_buf),
"/proc/%d/fd/%d", getpid(), fm->fd) < 0) {
log_error("Could not format pid path.");
return 0;
}
if ((len = readlink(path_buf, link_buf, sizeof(link_buf))) < 0) {
log_error("readlink failed for /proc/%d/fd/%d.",
getpid(), fm->fd);
return 0;
}
/*
* Try to re-open the file, from the path now reported in /proc/pid/fd.
*/
if ((fd = open(link_buf, O_RDONLY)) < 0)
fm->deleted = 1;
if ((same = _filemap_monitor_check_same_file(fm->fd, fd)) < 0)
return 0;
if ((fd > 0) && close(fd))
log_error("Error closing fd %d", fd);
/* Should not happen with normal /proc. */
if ((fd > 0) && !same) {
log_error("File descriptor mismatch: %d and %s (read from %s) "
"are not the same file!", fm->fd, link_buf, path_buf);
return 0;
}
return 1;
}
static int _daemonise(struct filemap_monitor *fm)
{
pid_t pid = 0, sid;
int fd;
if (!(sid = setsid())) {
_early_log("setsid failed.");
return 0;
}
if ((pid = fork()) < 0) {
_early_log("Failed to fork daemon process.");
return 0;
}
if (pid > 0) {
if (_verbose)
_early_log("Started dmfilemapd with pid=%d", pid);
exit(0);
}
if (chdir("/")) {
_early_log("Failed to change directory.");
return 0;
}
if (!_verbose) {
if (close(STDIN_FILENO))
_early_log("Error closing stdin");
if (close(STDOUT_FILENO))
_early_log("Error closing stdout");
if (close(STDERR_FILENO))
_early_log("Error closing stderr");
if ((open("/dev/null", O_RDONLY) < 0) ||
(open("/dev/null", O_WRONLY) < 0) ||
(open("/dev/null", O_WRONLY) < 0)) {
_early_log("Error opening stdio streams.");
return 0;
}
}
for (fd = sysconf(_SC_OPEN_MAX) - 1; fd > STDERR_FILENO; fd--) {
if (fd == fm->fd)
continue;
close(fd);
}
return 1;
}
static int _update_regions(struct dm_stats *dms, struct filemap_monitor *fm)
{
uint64_t *regions = NULL, *region, nr_regions = 0;
regions = dm_stats_update_regions_from_fd(dms, fm->fd, fm->group_id);
if (!regions) {
log_error("Failed to update filemap regions for group_id="
FMTu64 ".", fm->group_id);
return 0;
}
for (region = regions; *region != DM_STATS_REGIONS_ALL; region++)
nr_regions++;
if (regions[0] != fm->group_id) {
log_warn("group_id changed from " FMTu64 " to " FMTu64,
fm->group_id, regions[0]);
fm->group_id = regions[0];
}
fm->nr_regions = nr_regions;
return 1;
}
static int _dmfilemapd(struct filemap_monitor *fm)
{
int running = 1, check = 0, open = 0;
const char *program_id;
struct dm_stats *dms;
/*
* The correct program_id is retrieved from the group leader
* following the call to dm_stats_list().
*/
dms = dm_stats_create(NULL);
if (!dm_stats_bind_from_fd(dms, fm->fd)) {
log_error("Could not bind dm_stats handle to file descriptor "
"%d", fm->fd);
goto bad;
}
if (!_filemap_monitor_set_notify(fm))
goto bad;
if (!dm_stats_list(dms, NULL)) {
log_error("Failed to list stats handle.");
goto bad;
}
/*
* Take the program_id for new regions (created by calls to
* dm_stats_update_regions_from_fd()) from the value used by
* the group leader.
*/
program_id = dm_stats_get_region_program_id(dms, fm->group_id);
if (program_id)
fm->program_id = dm_strdup(program_id);
else
fm->program_id = NULL;
do {
if (!dm_stats_group_present(dms, fm->group_id)) {
log_info("Filemap group removed: exiting.");
running = 0;
continue;
}
if ((check = _filemap_monitor_get_events(fm)) < 0)
goto bad;
if (!check)
goto wait;
if ((check = _filemap_fd_check_changed(fm)) < 0)
goto bad;
if (!check)
goto wait;
if (!_update_regions(dms, fm))
goto bad;
wait:
_filemap_monitor_wait(FILEMAPD_WAIT_USECS);
running = !!fm->nr_regions;
/* mode=inode termination condions */
if (fm->mode == DM_FILEMAPD_FOLLOW_INODE) {
if (!_filemap_monitor_check_file_unlinked(fm))
goto bad;
if (fm->deleted && !(open = _is_open(fm->path))) {
log_info("File unlinked and closed: exiting.");
running = 0;
} else if (fm->deleted && open)
log_verbose("File unlinked and open: "
"continuing.");
}
if (!dm_stats_list(dms, NULL)) {
log_error("Failed to list stats handle.");
goto bad;
}
} while (running);
_filemap_monitor_destroy(fm);
dm_stats_destroy(dms);
return 0;
bad:
_filemap_monitor_destroy(fm);
dm_stats_destroy(dms);
log_error("Exiting");
return 1;
}
static const char * _mode_names[] = {
"inode",
"path"
};
/*
* dmfilemapd <fd> <group_id> <path> <mode> [<foreground>[<log_level>]]
*/
int main(int argc, char **argv)
{
struct filemap_monitor fm;
if (!_parse_args(argc, argv, &fm))
return 1;
_setup_logging();
log_info("Starting dmfilemapd with fd=%d, group_id=" FMTu64 " "
"mode=%s, path=%s", fm.fd, fm.group_id,
_mode_names[fm.mode], fm.path);
if (!_foreground && !_daemonise(&fm))
return 1;
return _dmfilemapd(&fm);
}

View File

@ -127,6 +127,9 @@
/* Path to dmeventd pidfile. */
#undef DMEVENTD_PIDFILE
/* Define to 1 to enable the device-mapper filemap daemon. */
#undef DMFILEMAPD
/* Define to enable compat protocol */
#undef DM_COMPAT

View File

@ -1,6 +1,8 @@
dm_bit_get_last
dm_bit_get_prev
dm_filemapd_mode_from_string
dm_stats_update_regions_from_fd
dm_bitset_parse_list
dm_stats_bind_from_fd
dm_stats_start_filemapd
dm_tree_node_add_raid_target_with_params_v2

View File

@ -1369,6 +1369,69 @@ uint64_t *dm_stats_create_regions_from_fd(struct dm_stats *dms, int fd,
uint64_t *dm_stats_update_regions_from_fd(struct dm_stats *dms, int fd,
uint64_t group_id);
/*
* The file map monitoring daemon can monitor files in two distinct
* ways: the mode affects the behaviour of the daemon when a file
* under monitoring is renamed or unlinked, and the conditions which
* cause the daemon to terminate.
*
* In both modes, the daemon will always shut down when the group
* being monitored is deleted.
*
* Follow inode:
* The daemon follows the inode of the file, as it was at the time the
* daemon started. The file descriptor referencing the file is kept
* open at all times, and the daemon will exit when it detects that
* the file has been unlinked and it is the last holder of a reference
* to the file.
*
* This mode is useful if the file is expected to be renamed, or moved
* within the file system, while it is being monitored.
*
* Follow path:
* The daemon follows the path that was given on the daemon command
* line. The file descriptor referencing the file is re-opened on each
* iteration of the daemon, and the daemon will exit if no file exists
* at this location (a tolerance is allowed so that a brief delay
* between unlink() and creat() is permitted).
*
* This mode is useful if the file is updated by unlinking the original
* and placing a new file at the same path.
*/
typedef enum {
DM_FILEMAPD_FOLLOW_INODE,
DM_FILEMAPD_FOLLOW_PATH,
DM_FILEMAPD_FOLLOW_NONE
} dm_filemapd_mode_t;
/*
* Parse a string representation of a dmfilemapd mode.
*
* Returns a valid dm_filemapd_mode_t value on success, or
* DM_FILEMAPD_FOLLOW_NONE on error.
*/
dm_filemapd_mode_t dm_filemapd_mode_from_string(const char *mode_str);
/*
* Start the dmfilemapd filemap monitoring daemon for the specified
* file descriptor, group, and file system path. The daemon will
* monitor the file for allocation changes, and when a change is
* detected, call dm_stats_update_regions_from_fd() to update the
* mapped regions for the file.
*
* The mode parameter controls the behaviour of the daemon when the
* file being monitored is unlinked or moved: see the comments for
* dm_filemapd_mode_t for a full description and possible values.
*
* The daemon can be stopped at any time by sending SIGTERM to the
* daemon pid.
*/
int dm_stats_start_filemapd(int fd, uint64_t group_id, const char *path,
dm_filemapd_mode_t mode, unsigned foreground,
unsigned verbose);
/*
* Call this to actually run the ioctl.
*/

View File

@ -4878,6 +4878,154 @@ out:
return NULL;
}
#ifdef DMFILEMAPD
static const char *_filemapd_mode_names[] = {
"inode",
"path",
NULL
};
dm_filemapd_mode_t dm_filemapd_mode_from_string(const char *mode_str)
{
dm_filemapd_mode_t mode = DM_FILEMAPD_FOLLOW_INODE;
const char **mode_name;
if (mode_str) {
for (mode_name = _filemapd_mode_names; *mode_name; mode_name++)
if (!strcmp(*mode_name, mode_str))
break;
if (*mode_name)
mode = DM_FILEMAPD_FOLLOW_INODE
+ (mode_name - _filemapd_mode_names);
else {
log_error("Could not parse dmfilemapd mode: %s",
mode_str);
return DM_FILEMAPD_FOLLOW_NONE;
}
}
return mode;
}
#define DM_FILEMAPD "dmfilemapd"
#define NR_FILEMAPD_ARGS 6
/*
* Start dmfilemapd to monitor the specified file descriptor, and to
* update the group given by 'group_id' when the file's allocation
* changes.
*
* usage: dmfilemapd <fd> <group_id> <mode> [<foreground>[<log_level>]]
*/
int dm_stats_start_filemapd(int fd, uint64_t group_id, const char *path,
dm_filemapd_mode_t mode, unsigned foreground,
unsigned verbose)
{
char fd_str[8], group_str[8], fg_str[2], verb_str[2];
const char *mode_str = _filemapd_mode_names[mode];
char *args[NR_FILEMAPD_ARGS + 1];
pid_t pid = 0;
int argc = 0;
if (fd < 0) {
log_error("dmfilemapd file descriptor must be "
"non-negative: %d", fd);
return 0;
}
if (mode < DM_FILEMAPD_FOLLOW_INODE
|| mode > DM_FILEMAPD_FOLLOW_PATH) {
log_error("Invalid dmfilemapd mode argument: "
"Must be DM_FILEMAPD_FOLLOW_INODE or "
"DM_FILEMAPD_FOLLOW_PATH");
return 0;
}
if (foreground > 1) {
log_error("Invalid dmfilemapd foreground argument. "
"Must be 0 or 1: %d.", foreground);
return 0;
}
if (verbose > 3) {
log_error("Invalid dmfilemapd verbose argument. "
"Must be 0..3: %d.", verbose);
return 0;
}
/* set argv[0] */
args[argc++] = (char *) DM_FILEMAPD;
/* set <fd> */
if ((dm_snprintf(fd_str, sizeof(fd_str), "%d", fd)) < 0) {
log_error("Could not format fd argument.");
return 0;
}
args[argc++] = fd_str;
/* set <group_id> */
if ((dm_snprintf(group_str, sizeof(group_str), FMTu64, group_id)) < 0) {
log_error("Could not format group_id argument.");
return 0;
}
args[argc++] = group_str;
/* set <path> */
args[argc++] = (char *) path;
/* set <mode> */
args[argc++] = (char *) mode_str;
/* set <foreground> */
if ((dm_snprintf(fg_str, sizeof(fg_str), "%u", foreground)) < 0) {
log_error("Could not format foreground argument.");
return 0;
}
args[argc++] = fg_str;
/* set <verbose> */
if ((dm_snprintf(verb_str, sizeof(verb_str), "%u", verbose)) < 0) {
log_error("Could not format verbose argument.");
return 0;
}
args[argc++] = verb_str;
/* terminate args[argc] */
args[argc] = NULL;
log_very_verbose("Spawning daemon as '%s %d " FMTu64 " %s %s %u %u'",
*args, fd, group_id, path, mode_str,
foreground, verbose);
if (!foreground && ((pid = fork()) < 0)) {
log_error("Failed to fork dmfilemapd process.");
return 0;
}
if (pid > 0) {
log_very_verbose("Forked dmfilemapd process as pid %d", pid);
return 1;
}
execvp(args[0], args);
log_error("execvp() failed.");
if (!foreground)
_exit(127);
return 0;
}
# else /* !DMFILEMAPD */
dm_filemapd_mode_t dm_filemapd_mode_from_string(const char *mode_str)
{
return 0;
};
int dm_stats_start_filemapd(int fd, uint64_t group_id, const char *path,
dm_filemapd_mode_t mode, unsigned foreground,
unsigned verbose)
{
log_error("dmfilemapd support disabled.");
return 0;
}
#endif /* DMFILEMAPD */
#else /* HAVE_LINUX_FIEMAP */
uint64_t *dm_stats_create_regions_from_fd(struct dm_stats *dms, int fd,
@ -4895,6 +5043,13 @@ uint64_t *dm_stats_update_regions_from_fd(struct dm_stats *dms, int fd,
log_error("File mapping requires FIEMAP ioctl support.");
return 0;
}
int dm_stats_start_filemapd(struct dm_stats *dms, int fd, uint64_t group_id,
const char *path)
{
log_error("File mapping requires FIEMAP ioctl support.");
return 0;
}
#endif /* HAVE_LINUX_FIEMAP */
/*