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Commit bf76c012 by Christian Brauner
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Split bdev into modules: lxcnbd

The functions - clone_attach_nbd(); - do_attach_nbd(); - nbd_busy(); - nbd_detach(); - nbd_get_partition(); - wait_for_partition(); move from bdev.c to lxcnbd.c. They remain static The functions - attach_nbd(); - detach_nbd_idx(); - nbd_clonepaths(); - nbd_create(); - nbd_destroy(); - nbd_detect(); - nbd_mount(); - nbd_umount(); - requires_nbd(); move from bdev.c to lxcnbd.{c,h}. They all become extern. The struct - struct nbd_attach_data moves from bdev.c to lxcnbd.c. Adapt Makefile.am to include lxcnbd.{c,h}. The structs - struct bdev; /* defined in bdev.h */ - struct bdev_specs; /* defined in lxccontainer.h */ - struct lxc_conf; /* defined conf.h */ are forward declared/put as incomplete types into lxcnbd.h as the functions associated with nbd need access to it. Signed-off-by: 's avatarChristian Brauner <christian.brauner@mailbox.org>
parent 3ceb2820
Showing with 422 additions and 342 deletions
src/lxc/Makefile.am
......@@ -12,6 +12,7 @@ noinst_HEADERS = \
bdev/lxcdir.h \
bdev/lxcloop.h \
bdev/lxclvm.h \
bdev/lxcnbd.h \
bdev/lxcoverlay.h \
bdev/lxcrbd.h \
bdev/lxcrsync.h \
......@@ -74,6 +75,7 @@ liblxc_so_SOURCES = \
bdev/lxcdir.c bdev/lxcdir.h \
bdev/lxcloop.c bdev/lxcloop.h \
bdev/lxclvm.c bdev/lxclvm.h \
bdev/lxcnbd.c bdev/lxcnbd.h \
bdev/lxcoverlay.c bdev/lxcoverlay.h \
bdev/lxcrbd.c bdev/lxcrbd.h \
bdev/lxcrsync.c bdev/lxcrsync.h \
......
src/lxc/bdev/bdev.c
......@@ -58,6 +58,7 @@
#include "lxclock.h"
#include "lxclvm.h"
#include "lxcloop.h"
#include "lxcnbd.h"
#include "lxcoverlay.h"
#include "lxcrbd.h"
#include "lxcrsync.h"
......@@ -140,6 +141,18 @@ static const struct bdev_ops lvm_ops = {
.can_backup = false,
};
/* nbd */
const struct bdev_ops nbd_ops = {
.detect = &nbd_detect,
.mount = &nbd_mount,
.umount = &nbd_umount,
.clone_paths = &nbd_clonepaths,
.destroy = &nbd_destroy,
.create = &nbd_create,
.can_snapshot = true,
.can_backup = false,
};
/* overlay */
static const struct bdev_ops ovl_ops = {
.detect = &ovl_detect,
......@@ -176,33 +189,13 @@ static const struct bdev_ops zfs_ops = {
.can_backup = true,
};
/* functions associated with an nbd bdev struct */
static bool attach_nbd(char *src, struct lxc_conf *conf);
static bool clone_attach_nbd(const char *nbd, const char *path);
static int do_attach_nbd(void *d);
static int nbd_get_partition(const char *src);
static bool nbd_busy(int idx);
static int nbd_clonepaths(struct bdev *orig, struct bdev *new,
const char *oldname, const char *cname,
const char *oldpath, const char *lxcpath, int snap,
uint64_t newsize, struct lxc_conf *conf);
static int nbd_create(struct bdev *bdev, const char *dest, const char *n,
struct bdev_specs *specs);
static void nbd_detach(const char *path);
static int nbd_destroy(struct bdev *orig);
static int nbd_detect(const char *path);
static int nbd_mount(struct bdev *bdev);
static int nbd_umount(struct bdev *bdev);
static bool requires_nbd(const char *path);
static bool wait_for_partition(const char *path);
/* helpers */
/*
* These are copied from conf.c. However as conf.c will be moved to using
* the callback system, they can be pulled from there eventually, so we
* don't need to pollute utils.c with these low level functions
*/
static int find_fstype_cb(char* buffer, void *data);
static int find_fstype_cb(char *buffer, void *data);
static char *linkderef(char *path, char *dest);
static bool unpriv_snap_allowed(struct bdev *b, const char *t, bool snap,
bool maybesnap);
......@@ -512,317 +505,6 @@ int is_blktype(struct bdev *b)
return 0;
}
//
// nbd dev ops
//
static int nbd_detect(const char *path)
{
if (strncmp(path, "nbd:", 4) == 0)
return 1;
return 0;
}
struct nbd_attach_data {
const char *nbd;
const char *path;
};
static void nbd_detach(const char *path)
{
int ret;
pid_t pid = fork();
if (pid < 0) {
SYSERROR("Error forking to detach nbd");
return;
}
if (pid) {
ret = wait_for_pid(pid);
if (ret < 0)
ERROR("nbd disconnect returned an error");
return;
}
execlp("qemu-nbd", "qemu-nbd", "-d", path, NULL);
SYSERROR("Error executing qemu-nbd");
exit(1);
}
static int do_attach_nbd(void *d)
{
struct nbd_attach_data *data = d;
const char *nbd, *path;
pid_t pid;
sigset_t mask;
int sfd;
ssize_t s;
struct signalfd_siginfo fdsi;
sigemptyset(&mask);
sigaddset(&mask, SIGHUP);
sigaddset(&mask, SIGCHLD);
nbd = data->nbd;
path = data->path;
if (sigprocmask(SIG_BLOCK, &mask, NULL) == -1) {
SYSERROR("Error blocking signals for nbd watcher");
exit(1);
}
sfd = signalfd(-1, &mask, 0);
if (sfd == -1) {
SYSERROR("Error opening signalfd for nbd task");
exit(1);
}
if (prctl(PR_SET_PDEATHSIG, SIGHUP, 0, 0, 0) < 0)
SYSERROR("Error setting parent death signal for nbd watcher");
pid = fork();
if (pid) {
for (;;) {
s = read(sfd, &fdsi, sizeof(struct signalfd_siginfo));
if (s != sizeof(struct signalfd_siginfo))
SYSERROR("Error reading from signalfd");
if (fdsi.ssi_signo == SIGHUP) {
/* container has exited */
nbd_detach(nbd);
exit(0);
} else if (fdsi.ssi_signo == SIGCHLD) {
int status;
/* If qemu-nbd fails, or is killed by a signal,
* then exit */
while (waitpid(-1, &status, WNOHANG) > 0) {
if ((WIFEXITED(status) && WEXITSTATUS(status) != 0) ||
WIFSIGNALED(status)) {
nbd_detach(nbd);
exit(1);
}
}
}
}
}
close(sfd);
if (sigprocmask(SIG_UNBLOCK, &mask, NULL) == -1)
WARN("Warning: unblocking signals for nbd watcher");
execlp("qemu-nbd", "qemu-nbd", "-c", nbd, path, NULL);
SYSERROR("Error executing qemu-nbd");
exit(1);
}
static bool clone_attach_nbd(const char *nbd, const char *path)
{
pid_t pid;
struct nbd_attach_data data;
data.nbd = nbd;
data.path = path;
pid = lxc_clone(do_attach_nbd, &data, CLONE_NEWPID);
if (pid < 0)
return false;
return true;
}
static bool nbd_busy(int idx)
{
char path[100];
int ret;
ret = snprintf(path, 100, "/sys/block/nbd%d/pid", idx);
if (ret < 0 || ret >= 100)
return true;
return file_exists(path);
}
static bool attach_nbd(char *src, struct lxc_conf *conf)
{
char *orig = alloca(strlen(src)+1), *p, path[50];
int i = 0;
strcpy(orig, src);
/* if path is followed by a partition, drop that for now */
p = strchr(orig, ':');
if (p)
*p = '\0';
while (1) {
sprintf(path, "/dev/nbd%d", i);
if (!file_exists(path))
return false;
if (nbd_busy(i)) {
i++;
continue;
}
if (!clone_attach_nbd(path, orig))
return false;
conf->nbd_idx = i;
return true;
}
}
static bool requires_nbd(const char *path)
{
if (strncmp(path, "nbd:", 4) == 0)
return true;
return false;
}
/*
* attach_block_device returns true if all went well,
* meaning either a block device was attached or was not
* needed. It returns false if something went wrong and
* container startup should be stopped.
*/
bool attach_block_device(struct lxc_conf *conf)
{
char *path;
if (!conf->rootfs.path)
return true;
path = conf->rootfs.path;
if (!requires_nbd(path))
return true;
path = strchr(path, ':');
if (!path)
return false;
path++;
if (!attach_nbd(path, conf))
return false;
return true;
}
void detach_nbd_idx(int idx)
{
int ret;
char path[50];
ret = snprintf(path, 50, "/dev/nbd%d", idx);
if (ret < 0 || ret >= 50)
return;
nbd_detach(path);
}
void detach_block_device(struct lxc_conf *conf)
{
if (conf->nbd_idx != -1)
detach_nbd_idx(conf->nbd_idx);
}
/*
* Pick the partition # off the end of a nbd:file:p
* description. Return 1-9 for the partition id, or 0
* for no partition.
*/
static int nbd_get_partition(const char *src)
{
char *p = strchr(src, ':');
if (!p)
return 0;
p = strchr(p+1, ':');
if (!p)
return 0;
p++;
if (*p < '1' || *p > '9')
return 0;
return *p - '0';
}
static bool wait_for_partition(const char *path)
{
int count = 0;
while (count < 5) {
if (file_exists(path))
return true;
sleep(1);
count++;
}
ERROR("Device %s did not show up after 5 seconds", path);
return false;
}
static int nbd_mount(struct bdev *bdev)
{
int ret = -1, partition;
char path[50];
if (strcmp(bdev->type, "nbd"))
return -22;
if (!bdev->src || !bdev->dest)
return -22;
/* nbd_idx should have been copied by bdev_init from the lxc_conf */
if (bdev->nbd_idx < 0)
return -22;
partition = nbd_get_partition(bdev->src);
if (partition)
ret = snprintf(path, 50, "/dev/nbd%dp%d", bdev->nbd_idx,
partition);
else
ret = snprintf(path, 50, "/dev/nbd%d", bdev->nbd_idx);
if (ret < 0 || ret >= 50) {
ERROR("Error setting up nbd device path");
return ret;
}
/* It might take awhile for the partition files to show up */
if (partition) {
if (!wait_for_partition(path))
return -2;
}
ret = mount_unknown_fs(path, bdev->dest, bdev->mntopts);
if (ret < 0)
ERROR("Error mounting %s", bdev->src);
return ret;
}
static int nbd_create(struct bdev *bdev, const char *dest, const char *n,
struct bdev_specs *specs)
{
return -ENOSYS;
}
static int nbd_clonepaths(struct bdev *orig, struct bdev *new,
const char *oldname, const char *cname,
const char *oldpath, const char *lxcpath, int snap,
uint64_t newsize, struct lxc_conf *conf)
{
return -ENOSYS;
}
static int nbd_destroy(struct bdev *orig)
{
return -ENOSYS;
}
static int nbd_umount(struct bdev *bdev)
{
int ret;
if (strcmp(bdev->type, "nbd"))
return -22;
if (!bdev->src || !bdev->dest)
return -22;
ret = umount(bdev->dest);
return ret;
}
static const struct bdev_ops nbd_ops = {
.detect = &nbd_detect,
.mount = &nbd_mount,
.umount = &nbd_umount,
.clone_paths = &nbd_clonepaths,
.destroy = &nbd_destroy,
.create = &nbd_create,
.can_snapshot = true,
.can_backup = false,
};
static const struct bdev_type bdevs[] = {
{.name = "zfs", .ops = &zfs_ops,},
{.name = "lvm", .ops = &lvm_ops,},
......@@ -1249,3 +931,33 @@ int bdev_destroy_wrapper(void *data)
else
return 0;
}
/*
* attach_block_device returns true if all went well,
* meaning either a block device was attached or was not
* needed. It returns false if something went wrong and
* container startup should be stopped.
*/
bool attach_block_device(struct lxc_conf *conf)
{
char *path;
if (!conf->rootfs.path)
return true;
path = conf->rootfs.path;
if (!requires_nbd(path))
return true;
path = strchr(path, ':');
if (!path)
return false;
path++;
if (!attach_nbd(path, conf))
return false;
return true;
}
void detach_block_device(struct lxc_conf *conf)
{
if (conf->nbd_idx != -1)
detach_nbd_idx(conf->nbd_idx);
}
src/lxc/bdev/bdev.h
......@@ -128,15 +128,6 @@ bool bdev_destroy(struct lxc_conf *conf);
/* callback function to be used with userns_exec_1() */
int bdev_destroy_wrapper(void *data);
/*
* these are really for qemu-nbd support, as container shutdown
* must explicitly request device detach.
*/
bool attach_block_device(struct lxc_conf *conf);
void detach_block_device(struct lxc_conf *conf);
bool rootfs_is_blockdev(struct lxc_conf *conf);
/* Some helpers for lvm, rdb, and/or loop:
* Maybe they should move to a separate implementation and header-file
* (bdev_utils.{c,h}) which can be included in bdev.c?
......@@ -147,6 +138,12 @@ int do_mkfs(const char *path, const char *fstype);
int is_blktype(struct bdev *b);
int mount_unknown_fs(const char *rootfs, const char *target,
const char *options);
bool rootfs_is_blockdev(struct lxc_conf *conf);
/*
* these are really for qemu-nbd support, as container shutdown
* must explicitly request device detach.
*/
bool attach_block_device(struct lxc_conf *conf);
void detach_block_device(struct lxc_conf *conf);
#endif // __LXC_BDEV_H
src/lxc/bdev/lxcnbd.c 0 → 100644
/*
* lxc: linux Container library
*
* (C) Copyright IBM Corp. 2007, 2008
*
* Authors:
* Daniel Lezcano <daniel.lezcano at free.fr>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define _GNU_SOURCE
#include <errno.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include "bdev.h"
#include "log.h"
#include "lxcnbd.h"
#include "utils.h"
lxc_log_define(lxcnbd, lxc);
struct nbd_attach_data {
const char *nbd;
const char *path;
};
static bool clone_attach_nbd(const char *nbd, const char *path);
static int do_attach_nbd(void *d);
static bool nbd_busy(int idx);
static void nbd_detach(const char *path);
static int nbd_get_partition(const char *src);
static bool wait_for_partition(const char *path);
bool attach_nbd(char *src, struct lxc_conf *conf)
{
char *orig = alloca(strlen(src)+1), *p, path[50];
int i = 0;
strcpy(orig, src);
/* if path is followed by a partition, drop that for now */
p = strchr(orig, ':');
if (p)
*p = '\0';
while (1) {
sprintf(path, "/dev/nbd%d", i);
if (!file_exists(path))
return false;
if (nbd_busy(i)) {
i++;
continue;
}
if (!clone_attach_nbd(path, orig))
return false;
conf->nbd_idx = i;
return true;
}
}
void detach_nbd_idx(int idx)
{
int ret;
char path[50];
ret = snprintf(path, 50, "/dev/nbd%d", idx);
if (ret < 0 || ret >= 50)
return;
nbd_detach(path);
}
int nbd_clonepaths(struct bdev *orig, struct bdev *new, const char *oldname,
const char *cname, const char *oldpath, const char *lxcpath,
int snap, uint64_t newsize, struct lxc_conf *conf)
{
return -ENOSYS;
}
int nbd_create(struct bdev *bdev, const char *dest, const char *n,
struct bdev_specs *specs)
{
return -ENOSYS;
}
int nbd_destroy(struct bdev *orig)
{
return -ENOSYS;
}
int nbd_detect(const char *path)
{
if (strncmp(path, "nbd:", 4) == 0)
return 1;
return 0;
}
int nbd_mount(struct bdev *bdev)
{
int ret = -1, partition;
char path[50];
if (strcmp(bdev->type, "nbd"))
return -22;
if (!bdev->src || !bdev->dest)
return -22;
/* nbd_idx should have been copied by bdev_init from the lxc_conf */
if (bdev->nbd_idx < 0)
return -22;
partition = nbd_get_partition(bdev->src);
if (partition)
ret = snprintf(path, 50, "/dev/nbd%dp%d", bdev->nbd_idx,
partition);
else
ret = snprintf(path, 50, "/dev/nbd%d", bdev->nbd_idx);
if (ret < 0 || ret >= 50) {
ERROR("Error setting up nbd device path");
return ret;
}
/* It might take awhile for the partition files to show up */
if (partition) {
if (!wait_for_partition(path))
return -2;
}
ret = mount_unknown_fs(path, bdev->dest, bdev->mntopts);
if (ret < 0)
ERROR("Error mounting %s", bdev->src);
return ret;
}
int nbd_umount(struct bdev *bdev)
{
int ret;
if (strcmp(bdev->type, "nbd"))
return -22;
if (!bdev->src || !bdev->dest)
return -22;
ret = umount(bdev->dest);
return ret;
}
bool requires_nbd(const char *path)
{
if (strncmp(path, "nbd:", 4) == 0)
return true;
return false;
}
static int do_attach_nbd(void *d)
{
struct nbd_attach_data *data = d;
const char *nbd, *path;
pid_t pid;
sigset_t mask;
int sfd;
ssize_t s;
struct signalfd_siginfo fdsi;
sigemptyset(&mask);
sigaddset(&mask, SIGHUP);
sigaddset(&mask, SIGCHLD);
nbd = data->nbd;
path = data->path;
if (sigprocmask(SIG_BLOCK, &mask, NULL) == -1) {
SYSERROR("Error blocking signals for nbd watcher");
exit(1);
}
sfd = signalfd(-1, &mask, 0);
if (sfd == -1) {
SYSERROR("Error opening signalfd for nbd task");
exit(1);
}
if (prctl(PR_SET_PDEATHSIG, SIGHUP, 0, 0, 0) < 0)
SYSERROR("Error setting parent death signal for nbd watcher");
pid = fork();
if (pid) {
for (;;) {
s = read(sfd, &fdsi, sizeof(struct signalfd_siginfo));
if (s != sizeof(struct signalfd_siginfo))
SYSERROR("Error reading from signalfd");
if (fdsi.ssi_signo == SIGHUP) {
/* container has exited */
nbd_detach(nbd);
exit(0);
} else if (fdsi.ssi_signo == SIGCHLD) {
int status;
/* If qemu-nbd fails, or is killed by a signal,
* then exit */
while (waitpid(-1, &status, WNOHANG) > 0) {
if ((WIFEXITED(status) && WEXITSTATUS(status) != 0) ||
WIFSIGNALED(status)) {
nbd_detach(nbd);
exit(1);
}
}
}
}
}
close(sfd);
if (sigprocmask(SIG_UNBLOCK, &mask, NULL) == -1)
WARN("Warning: unblocking signals for nbd watcher");
execlp("qemu-nbd", "qemu-nbd", "-c", nbd, path, NULL);
SYSERROR("Error executing qemu-nbd");
exit(1);
}
static bool clone_attach_nbd(const char *nbd, const char *path)
{
pid_t pid;
struct nbd_attach_data data;
data.nbd = nbd;
data.path = path;
pid = lxc_clone(do_attach_nbd, &data, CLONE_NEWPID);
if (pid < 0)
return false;
return true;
}
static bool nbd_busy(int idx)
{
char path[100];
int ret;
ret = snprintf(path, 100, "/sys/block/nbd%d/pid", idx);
if (ret < 0 || ret >= 100)
return true;
return file_exists(path);
}
static void nbd_detach(const char *path)
{
int ret;
pid_t pid = fork();
if (pid < 0) {
SYSERROR("Error forking to detach nbd");
return;
}
if (pid) {
ret = wait_for_pid(pid);
if (ret < 0)
ERROR("nbd disconnect returned an error");
return;
}
execlp("qemu-nbd", "qemu-nbd", "-d", path, NULL);
SYSERROR("Error executing qemu-nbd");
exit(1);
}
/*
* Pick the partition # off the end of a nbd:file:p
* description. Return 1-9 for the partition id, or 0
* for no partition.
*/
static int nbd_get_partition(const char *src)
{
char *p = strchr(src, ':');
if (!p)
return 0;
p = strchr(p+1, ':');
if (!p)
return 0;
p++;
if (*p < '1' || *p > '9')
return 0;
return *p - '0';
}
static bool wait_for_partition(const char *path)
{
int count = 0;
while (count < 5) {
if (file_exists(path))
return true;
sleep(1);
count++;
}
ERROR("Device %s did not show up after 5 seconds", path);
return false;
}
src/lxc/bdev/lxcnbd.h 0 → 100644
/*
* lxc: linux Container library
*
* (C) Copyright IBM Corp. 2007, 2008
*
* Authors:
* Daniel Lezcano <daniel.lezcano at free.fr>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __LXC_NBD_H
#define __LXC_NBD_H
#define _GNU_SOURCE
#include <stdbool.h>
#include <stdint.h>
/* defined in bdev.h */
struct bdev;
/* defined in lxccontainer.h */
struct bdev_specs;
/* defined conf.h */
struct lxc_conf;
/*
* Functions associated with an nbd bdev struct.
*/
int nbd_clonepaths(struct bdev *orig, struct bdev *new, const char *oldname,
const char *cname, const char *oldpath, const char *lxcpath,
int snap, uint64_t newsize, struct lxc_conf *conf);
int nbd_create(struct bdev *bdev, const char *dest, const char *n,
struct bdev_specs *specs);
int nbd_destroy(struct bdev *orig);
int nbd_detect(const char *path);
int nbd_mount(struct bdev *bdev);
int nbd_umount(struct bdev *bdev);
/* helpers */
bool attach_nbd(char *src, struct lxc_conf *conf);
void detach_nbd_idx(int idx);
bool requires_nbd(const char *path);
#endif /* __LXC_NBD_H */
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