dir: improve dir backend

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/storage/dir.c b/src/lxc/storage/dir.c
index b657cc0091cb50dfa347eee1c59430e7364c5e0e..18a10a42f9dfe43460c8374cea19fc1a4a1aab78 100644 (file)
--- a/src/lxc/storage/dir.c
+++ b/src/lxc/storage/dir.c
@@ -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,
@@ -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;
@@ -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;
 }
@@ -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;
 }
@@ -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;
@@ -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);
 }