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systemd-mount: support unmounting loop devices by backing files (#6211)

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This makes `systemd-umount` or `systemd-mount -u` support unmounting
loop devices by the corresponding backing files, like
`systemd-mount --umount /tmp/foo.img /tmp/bar.img`

Fixes #6206.
This commit is contained in:
Yu Watanabe 2017-06-29 03:19:38 +09:00 committed by Zbigniew Jędrzejewski-Szmek
parent 0d787d5ff8
commit 6f6165bf7d
2 changed files with 98 additions and 52 deletions
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5
man/systemd-mount.xml
View file

@ -256,8 +256,9 @@
<listitem><para>Stop the mount and automount units corresponding to the specified mount points
<replaceable>WHERE</replaceable> or the devices <replaceable>WHAT</replaceable>.
<command>systemd-mount</command> with this option or <command>systemd-umount</command> can take multiple arguments
which can be path, device, or <filename>/etc/fstab</filename> style node name, like
<command>systemd-mount --umount /path/to/umount /dev/sda1 UUID=xxxxxx-xxxx LABEL=xxxxx</command>.
which can be mount points, devices, <filename>/etc/fstab</filename> style node names, or backing files
corresponding to loop devices, like
<command>systemd-mount --umount /path/to/umount /dev/sda1 UUID=xxxxxx-xxxx LABEL=xxxxx /path/to/disk.img</command>.
</para>
</listitem>
</varlistentry>

145
src/mount/mount-tool.c
View file

@ -25,13 +25,16 @@
#include "bus-error.h"
#include "bus-unit-util.h"
#include "bus-util.h"
#include "dirent-util.h"
#include "escape.h"
#include "fd-util.h"
#include "fileio.h"
#include "fstab-util.h"
#include "pager.h"
#include "parse-util.h"
#include "path-util.h"
#include "spawn-polkit-agent.h"
#include "stat-util.h"
#include "strv.h"
#include "udev-util.h"
#include "unit-name.h"
@ -636,8 +639,7 @@ static int start_transient_automount(
static int stop_mount(
sd_bus *bus,
const char *where,
const char *suffix,
bool ignore_enoent) {
const char *suffix) {
_cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
@ -677,11 +679,8 @@ static int stop_mount(
polkit_agent_open_if_enabled();
r = sd_bus_call(bus, m, 0, &error, &reply);
if (r < 0) {
if (r != -ENOENT || !ignore_enoent)
return log_error_errno(r, "Failed to stop mount unit: %s", bus_error_message(&error, r));
return r;
}
if (r < 0)
return log_error_errno(r, "Failed to stop mount unit: %s", bus_error_message(&error, r));
if (w) {
const char *object;
@ -705,8 +704,7 @@ static int stop_mount(
static int stop_mounts(
sd_bus *bus,
const char *where,
bool ignore_enoent) {
const char *where) {
int r;
@ -720,11 +718,11 @@ static int stop_mounts(
return -EINVAL;
}
r = stop_mount(bus, where, ".mount", ignore_enoent);
r = stop_mount(bus, where, ".mount");
if (r < 0)
return r;
r = stop_mount(bus, where, ".automount", ignore_enoent);
r = stop_mount(bus, where, ".automount");
if (r < 0)
return r;
@ -769,15 +767,13 @@ static int umount_by_mountinfo(sd_bus *bus, const char *what) {
r = cunescape(path, UNESCAPE_RELAX, &where);
if (r < 0) {
if (r2 >= 0)
r2 = r;
r2 = r;
continue;
}
r = stop_mounts(bus, where, false);
r = stop_mounts(bus, where);
if (r < 0) {
if (r2 >= 0)
r2 = r;
r2 = r;
continue;
}
}
@ -791,7 +787,7 @@ static int umount_by_device(sd_bus *bus, const char *what) {
_cleanup_free_ char *where = NULL;
struct stat st;
const char *v;
int r = 0, r2;
int r, r2 = 0;
assert(what);
@ -799,7 +795,7 @@ static int umount_by_device(sd_bus *bus, const char *what) {
return log_error_errno(errno, "Can't stat %s: %m", what);
if (!S_ISBLK(st.st_mode)) {
log_error("Path %s is not a block device, don't know what to do.", what);
log_error("Not a block device: %s", what);
return -ENOTBLK;
}
@ -822,17 +818,74 @@ static int umount_by_device(sd_bus *bus, const char *what) {
where = strdup(v);
if (!where)
return log_oom();
r = stop_mounts(bus, where, false);
r2 = stop_mounts(bus, where);
}
v = udev_device_get_devnode(d);
if (!isempty(v)) {
r2 = umount_by_mountinfo(bus, v);
if (r2 < 0)
return r2;
r = umount_by_mountinfo(bus, v);
if (r < 0)
return r;
}
return r;
return r2;
}
static int umount_loop(sd_bus *bus, const char *backing_file) {
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
int r, r2 = 0;
bool found = false;
assert(backing_file);
d = opendir("/sys/devices/virtual/block");
if (!d) {
if (errno == ENOENT)
return log_error_errno(errno, "File %s is not mounted.", backing_file);
return log_error_errno(errno, "Can't open directory /sys/devices/virtual/block: %m");
}
FOREACH_DIRENT(de, d, return -errno) {
_cleanup_free_ char *sys = NULL, *what = NULL, *fname = NULL;
dirent_ensure_type(d, de);
if (de->d_type != DT_DIR)
continue;
if (!startswith(de->d_name, "loop"))
continue;
sys = strjoin("/sys/devices/virtual/block/", de->d_name, "/loop/backing_file");
if (!sys)
return log_oom();
r = read_one_line_file(sys, &fname);
if (r < 0) {
if (r != -ENOENT)
r2 = log_error_errno(r, "Can't read %s: %m", sys);
continue;
}
if (!files_same(fname, backing_file, 0))
continue;
found = true;
what = strjoin("/dev/", de->d_name);
if (!what)
return log_oom();
r = umount_by_device(bus, what);
if (r < 0)
r2 = r;
}
if (!found)
return log_error_errno(ENOENT, "File %s is not mounted.", backing_file);
return r2;
}
static int action_umount(
@ -843,44 +896,36 @@ static int action_umount(
int i, r, r2 = 0;
for (i = optind; i < argc; i++) {
_cleanup_free_ char *what = NULL, *where = NULL, *u = NULL;
bool ignore_enoent;
_cleanup_free_ char *u = NULL, *p = NULL;
struct stat st;
u = fstab_node_to_udev_node(argv[i]);
if (!u)
return log_oom();
if (streq(u, argv[i])) {
r = path_make_absolute_cwd(argv[i], &where);
if (r < 0) {
log_error_errno(r, "Failed to make path absolute: %m");
if (r2 >= 0)
r2 = r;
} else {
path_kill_slashes(where);
ignore_enoent = is_device_path(where);
r = stop_mounts(bus, where, ignore_enoent);
if (r >= 0)
continue;
if ((r != -ENOENT || !ignore_enoent) && r2 >= 0)
r2 = r;
}
}
r = path_make_absolute_cwd(u, &what);
r = path_make_absolute_cwd(u, &p);
if (r < 0) {
log_error_errno(r, "Failed to make path absolute: %m");
if (r2 >= 0)
r2 = r;
r2 = log_error_errno(r, "Failed to make path absolute: %m");
continue;
}
path_kill_slashes(what);
path_kill_slashes(p);
if (!is_device_path(what))
continue;
if (stat(p, &st) < 0)
return log_error_errno(errno, "Can't stat %s: %m", p);
r = umount_by_device(bus, what);
if (r < 0 && r2 >= 0)
if (S_ISBLK(st.st_mode))
r = umount_by_device(bus, p);
else if (S_ISREG(st.st_mode))
r = umount_loop(bus, p);
else if (S_ISDIR(st.st_mode))
r = stop_mounts(bus, p);
else {
log_error("Invalid file type: %s", p);
r = -EINVAL;
}
if (r < 0)
r2 = r;
}