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dir: improve dir backend
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Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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@stgraber
Christian Brauner authored and stgraber committed Mar 26, 2020
1 parent 53209ca commit d06e151
Showing 1 changed file with 56 additions and 69 deletions.
125 changes: 56 additions & 69 deletions src/lxc/storage/dir.c
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Expand Up @@ -4,16 +4,20 @@
#define _GNU_SOURCE 1
#endif
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#include "config.h"
#include "log.h"
#include "macro.h"
#include "memory_utils.h"
#include "storage.h"
#include "utils.h"

lxc_log_define(dir, lxc);

/* For a simple directory bind mount, we substitute the old container name and
/*
* For a simple directory bind mount, we substitute the old container name and
* paths for the new.
*/
int dir_clonepaths(struct lxc_storage *orig, struct lxc_storage *new,
Expand All @@ -25,33 +29,26 @@ int dir_clonepaths(struct lxc_storage *orig, struct lxc_storage *new,
int ret;
size_t len;

if (snap) {
ERROR("Directories cannot be snapshotted");
return -1;
}
if (snap)
return log_error_errno(-EINVAL, EINVAL, "Directories cannot be snapshotted");

if (!orig->dest || !orig->src)
return -1;
return ret_errno(EINVAL);

len = strlen(lxcpath) + strlen(cname) + strlen("rootfs") + 4 + 3;
len = STRLITERALLEN("dir:") + strlen(lxcpath) + STRLITERALLEN("/") +
strlen(cname) + STRLITERALLEN("/rootfs") + 1;
new->src = malloc(len);
if (!new->src) {
ERROR("Failed to allocate memory");
return -1;
}
if (!new->src)
return ret_errno(ENOMEM);

ret = snprintf(new->src, len, "dir:%s/%s/rootfs", lxcpath, cname);
if (ret < 0 || (size_t)ret >= len) {
ERROR("Failed to create string");
return -1;
}
if (ret < 0 || (size_t)ret >= len)
return ret_errno(EIO);

src_no_prefix = lxc_storage_get_path(new->src, new->type);
new->dest = strdup(src_no_prefix);
if (!new->dest) {
ERROR("Failed to duplicate string \"%s\"", new->src);
return -1;
}
if (!new->dest)
return log_error_errno(-ENOMEM, ENOMEM, "Failed to duplicate string \"%s\"", new->src);

TRACE("Created new path \"%s\" for dir storage driver", new->dest);
return 0;
Expand All @@ -60,42 +57,37 @@ int dir_clonepaths(struct lxc_storage *orig, struct lxc_storage *new,
int dir_create(struct lxc_storage *bdev, const char *dest, const char *n,
struct bdev_specs *specs, const struct lxc_conf *conf)
{
__do_free char *bdev_src = NULL, *bdev_dest = NULL;
int ret;
const char *src;
size_t len;

/* strlen("dir:") */
len = 4;
len = STRLITERALLEN("dir:");
if (specs && specs->dir)
src = specs->dir;
else
src = dest;

len += strlen(src) + 1;
bdev->src = malloc(len);
if (!bdev->src) {
ERROR("Failed to allocate memory");
return -1;
}
bdev_src = malloc(len);
if (!bdev_src)
return ret_errno(ENOMEM);

ret = snprintf(bdev->src, len, "dir:%s", src);
if (ret < 0 || (size_t)ret >= len) {
ERROR("Failed to create string");
return -1;
}
ret = snprintf(bdev_src, len, "dir:%s", src);
if (ret < 0 || (size_t)ret >= len)
return ret_errno(EIO);

bdev->dest = strdup(dest);
if (!bdev->dest) {
ERROR("Failed to duplicate string \"%s\"", dest);
return -1;
}
bdev_dest = strdup(dest);
if (!bdev_dest)
return ret_errno(ENOMEM);

ret = mkdir_p(dest, 0755);
if (ret < 0) {
ERROR("Failed to create directory \"%s\"", dest);
return -1;
}
if (ret < 0)
return log_error_errno(-errno, errno, "Failed to create directory \"%s\"", dest);

TRACE("Created directory \"%s\"", dest);
bdev->src = move_ptr(bdev_src);
bdev->dest = move_ptr(bdev_dest);

return 0;
}
Expand All @@ -108,10 +100,8 @@ int dir_destroy(struct lxc_storage *orig)
src = lxc_storage_get_path(orig->src, orig->src);

ret = lxc_rmdir_onedev(src, NULL);
if (ret < 0) {
ERROR("Failed to delete \"%s\"", src);
return -1;
}
if (ret < 0)
return log_error_errno(ret, errno, "Failed to delete \"%s\"", src);

return 0;
}
Expand All @@ -125,10 +115,8 @@ bool dir_detect(const char *path)
return true;

ret = stat(path, &statbuf);
if (ret == -1 && errno == EPERM) {
SYSERROR("dir_detect: failed to look at \"%s\"", path);
return false;
}
if (ret == -1 && errno == EPERM)
return log_error_errno(false, errno, "dir_detect: failed to look at \"%s\"", path);

if (ret == 0 && S_ISDIR(statbuf.st_mode))
return true;
Expand All @@ -150,43 +138,42 @@ int dir_mount(struct lxc_storage *bdev)
return -22;

ret = parse_mntopts(bdev->mntopts, &mntflags, &mntdata);
if (ret < 0) {
ERROR("Failed to parse mount options \"%s\"", bdev->mntopts);
return -EINVAL;
}
if (ret < 0)
return log_error_errno(ret, errno, "Failed to parse mount options \"%s\"", bdev->mntopts);

ret = parse_propagationopts(bdev->mntopts, &pflags);
if (ret < 0) {
ERROR("Failed to parse propagation options \"%s\"", bdev->mntopts);
return -EINVAL;
}
if (ret < 0)
return log_error_errno(-EINVAL, EINVAL, "Failed to parse mount propagation options \"%s\"", bdev->mntopts);

src = lxc_storage_get_path(bdev->src, bdev->type);

ret = mount(src, bdev->dest, "bind", MS_BIND | MS_REC | mntflags | pflags, mntdata);
if ((0 == ret) && (mntflags & MS_RDONLY)) {
DEBUG("Remounting \"%s\" on \"%s\" readonly",
src ? src : "(none)", bdev->dest ? bdev->dest : "(none)");
if (ret < 0)
return log_error_errno(-errno, errno, "Failed to mount \"%s\" on \"%s\"", src, bdev->dest);

if (ret == 0 && (mntflags & MS_RDONLY)) {
mflags = add_required_remount_flags(src, bdev->dest, MS_BIND | MS_REC | mntflags | pflags | MS_REMOUNT);
ret = mount(src, bdev->dest, "bind", mflags, mntdata);
if (ret < 0)
return log_error_errno(-errno, errno, "Failed to remount \"%s\" on \"%s\" read-only with options \"%s\", mount flags \"%lu\", and propagation flags \"%lu\"",
src ? src : "(none)", bdev->dest ? bdev->dest : "(none)", mntdata, mflags, pflags);
else
DEBUG("Remounted \"%s\" on \"%s\" read-only with options \"%s\", mount flags \"%lu\", and propagation flags \"%lu\"",
src ? src : "(none)", bdev->dest ? bdev->dest : "(none)", mntdata, mflags, pflags);
}

if (ret < 0) {
SYSERROR("Failed to mount \"%s\" on \"%s\"", src, bdev->dest);
return -1;
}

TRACE("Mounted \"%s\" on \"%s\"", src, bdev->dest);
return ret;
TRACE("Mounted \"%s\" on \"%s\" with options \"%s\", mount flags \"%lu\", and propagation flags \"%lu\"",
src ? src : "(none)", bdev->dest ? bdev->dest : "(none)", mntdata, mflags, pflags);
return 0;
}

int dir_umount(struct lxc_storage *bdev)
{
if (strcmp(bdev->type, "dir"))
return -22;
return ret_errno(EINVAL);

if (!bdev->src || !bdev->dest)
return -22;
return ret_errno(EINVAL);

return umount(bdev->dest);
return umount2(bdev->dest, MNT_DETACH);
}

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