mount targets when relative are relative to the mounted rootfs dir (with absolute paths under the *not-mounted* rootfs dir being auto- translated to being under the mounted rootfs dir).
These paths would be relative to the containerdir. I think that's too confusing. Quoting Christian Brauner ([email protected]): > I now wonder if it wouldn't be smarter to force users to specify relative > paths > for upper and workdir > > lxc.mount.entry = /lower merged overlay > lowerdir=/lower,upper=upper,workdir=workdir,create=dir > > and fill in the missing path in mount_entry_create_*_dirs(). Otherwise these > mounts won't work out of the box when a clone of the container is made and > started... Thoughts? > > On Tue, Oct 06, 2015 at 08:38:13PM +0200, Christian Brauner wrote: > > When users wanted to mount overlay directories with lxc.mount.entry they > > had to > > create upperdirs and workdirs beforehand in order to mount them. To create > > it > > for them we add the functions mount_entry_create_overlay_dirs() and > > mount_entry_create_aufs_dirs() which do this for them. User can now simply > > specify e.g.: > > > > lxc.mount.entry = /lower merged overlay > > lowerdir=/lower,upper=/upper,workdir=/workdir,create=dir > > > > and /upper and /workdir will be created for them. /upper and /workdir need > > to > > be absolute paths to directories which are created under the containerdir > > (e.g. > > under $lxcpath/CONTAINERNAME/). Relative mountpoints, mountpoints outside > > the > > containerdir, and mountpoints within the container's rootfs are ignored. > > (The > > latter *might* change in the future should it be considered safe/useful.) > > > > Specifying > > > > lxc.mount.entry = /lower merged overlay > > lowerdir=/lower:/lower2,create=dir > > > > will lead to a read-only overlay mount in accordance with the > > kernel-documentation. > > > > Specifying > > > > lxc.mount.entry = /lower merged overlay lowerdir=/lower,create=dir > > > > will fail when no upperdir and workdir options are given. > > > > Signed-off-by: Christian Brauner <[email protected]> > > Acked-by: Serge E. Hallyn <[email protected]> > > --- > > src/lxc/conf.c | 162 > > ++++++++++++++++++++++++++++++++++++++++++++++++++++----- > > 1 file changed, 150 insertions(+), 12 deletions(-) > > > > diff --git a/src/lxc/conf.c b/src/lxc/conf.c > > index 6728c78..5a3209a 100644 > > --- a/src/lxc/conf.c > > +++ b/src/lxc/conf.c > > @@ -1815,13 +1815,151 @@ static void cull_mntent_opt(struct mntent *mntent) > > } > > } > > > > +static int mount_entry_create_overlay_dirs(const struct mntent *mntent, > > + const struct lxc_rootfs *rootfs) > > +{ > > + char *del = NULL; > > + char *lxcpath = NULL; > > + char *upperdir = NULL; > > + char *workdir = NULL; > > + char **opts = NULL; > > + size_t arrlen = 0; > > + size_t dirlen = 0; > > + size_t i; > > + size_t len = 0; > > + size_t rootfslen = 0; > > + > > + if (!rootfs->path) > > + return -1; > > + > > + opts = lxc_string_split(mntent->mnt_opts, ','); > > + if (opts) > > + arrlen = lxc_array_len((void **)opts); > > + else > > + return -1; > > + > > + for (i = 0; i < arrlen; i++) { > > + if (strstr(opts[i], "upperdir=") && (strlen(opts[i]) > (len = > > strlen("upperdir=")))) > > + upperdir = opts[i] + len; > > + else if (strstr(opts[i], "workdir=") && (strlen(opts[i]) > (len > > = strlen("workdir=")))) > > + workdir = opts[i] + len; > > + } > > + > > + lxcpath = strdup(rootfs->path); > > + if (!lxcpath) { > > + lxc_free_array((void **)opts, free); > > + return -1; > > + } > > + > > + del = strstr(lxcpath, "/rootfs"); > > + if (!del) { > > + free(lxcpath); > > + lxc_free_array((void **)opts, free); > > + return -1; > > + } > > + *del = '\0'; > > + > > + dirlen = strlen(lxcpath); > > + rootfslen = strlen(rootfs->path); > > + > > + /* We neither allow users to create upperdirs and workdirs outside the > > + * containerdir nor inside the rootfs. The latter might be debatable. */ > > + if (upperdir) > > + if ((strncmp(upperdir, lxcpath, dirlen) == 0) && > > (strncmp(upperdir, rootfs->path, rootfslen) != 0)) > > + if (mkdir_p(upperdir, 0755) < 0) { > > + WARN("Failed to create upperdir"); > > + } > > + > > + > > + if (workdir) > > + if ((strncmp(workdir, lxcpath, dirlen) == 0) && > > (strncmp(workdir, rootfs->path, rootfslen) != 0)) > > + if (mkdir_p(workdir, 0755) < 0) { > > + WARN("Failed to create workdir"); > > + } > > + > > + free(lxcpath); > > + lxc_free_array((void **)opts, free); > > + return 0; > > +} > > + > > +static int mount_entry_create_aufs_dirs(const struct mntent *mntent, > > + const struct lxc_rootfs *rootfs) > > +{ > > + char *del = NULL; > > + char *lxcpath = NULL; > > + char *scratch = NULL; > > + char *tmp = NULL; > > + char *upperdir = NULL; > > + char **opts = NULL; > > + size_t arrlen = 0; > > + size_t i; > > + size_t len = 0; > > + > > + if (!rootfs->path) > > + return -1; > > + > > + opts = lxc_string_split(mntent->mnt_opts, ','); > > + if (opts) > > + arrlen = lxc_array_len((void **)opts); > > + else > > + return -1; > > + > > + for (i = 0; i < arrlen; i++) { > > + if (strstr(opts[i], "br=") && (strlen(opts[i]) > (len = > > strlen("br=")))) > > + tmp = opts[i] + len; > > + } > > + if (!tmp) { > > + lxc_free_array((void **)opts, free); > > + return -1; > > + } > > + > > + upperdir = strtok_r(tmp, ":=", &scratch); > > + if (!upperdir) { > > + lxc_free_array((void **)opts, free); > > + return -1; > > + } > > + > > + lxcpath = strdup(rootfs->path); > > + if (!lxcpath) { > > + lxc_free_array((void **)opts, free); > > + return -1; > > + } > > + > > + del = strstr(lxcpath, "/rootfs"); > > + if (!del) { > > + free(lxcpath); > > + lxc_free_array((void **)opts, free); > > + return -1; > > + } > > + *del = '\0'; > > + > > + /* We neither allow users to create upperdirs outside the containerdir > > + * nor inside the rootfs. The latter might be debatable. */ > > + if ((strncmp(upperdir, lxcpath, strlen(lxcpath)) == 0) && > > (strncmp(upperdir, rootfs->path, strlen(rootfs->path)) != 0)) > > + if (mkdir_p(upperdir, 0755) < 0) { > > + WARN("Failed to create upperdir"); > > + } > > + > > + free(lxcpath); > > + lxc_free_array((void **)opts, free); > > + return 0; > > +} > > + > > static int mount_entry_create_dir_file(const struct mntent *mntent, > > - const char* path) > > + const char* path, const struct > > lxc_rootfs *rootfs) > > { > > char *pathdirname = NULL; > > int ret = 0; > > FILE *pathfile = NULL; > > > > + if (strncmp(mntent->mnt_type, "overlay", 7) == 0) { > > + if (mount_entry_create_overlay_dirs(mntent, rootfs) < 0) > > + return -1; > > + } else if (strncmp(mntent->mnt_type, "aufs", 4) == 0) { > > + if (mount_entry_create_aufs_dirs(mntent, rootfs) < 0) > > + return -1; > > + } > > + > > if (hasmntopt(mntent, "create=dir")) { > > if (mkdir_p(path, 0755) < 0) { > > WARN("Failed to create mount target '%s'", path); > > @@ -1839,23 +1977,23 @@ static int mount_entry_create_dir_file(const struct > > mntent *mntent, > > if (!pathfile) { > > WARN("Failed to create mount target '%s'", path); > > ret = -1; > > - } > > - else > > + } else { > > fclose(pathfile); > > + } > > } > > free(pathdirname); > > return ret; > > } > > > > static inline int mount_entry_on_generic(struct mntent *mntent, > > - const char* path, const char *rootfs) > > + const char* path, const struct lxc_rootfs *rootfs) > > { > > unsigned long mntflags; > > char *mntdata; > > int ret; > > bool optional = hasmntopt(mntent, "optional") != NULL; > > > > - ret = mount_entry_create_dir_file(mntent, path); > > + ret = mount_entry_create_dir_file(mntent, path, rootfs); > > > > if (ret < 0) > > return optional ? 0 : -1; > > @@ -1867,11 +2005,11 @@ static inline int mount_entry_on_generic(struct > > mntent *mntent, > > return -1; > > } > > > > - ret = mount_entry(mntent->mnt_fsname, path, mntent->mnt_type, > > - mntflags, mntdata, optional, rootfs); > > + ret = mount_entry(mntent->mnt_fsname, path, mntent->mnt_type, mntflags, > > + mntdata, optional, > > + rootfs->path ? rootfs->mount : NULL); > > > > free(mntdata); > > - > > return ret; > > } > > > > @@ -1924,17 +2062,17 @@ skipabs: > > return -1; > > } > > > > - return mount_entry_on_generic(mntent, path, rootfs->mount); > > + return mount_entry_on_generic(mntent, path, rootfs); > > } > > > > static int mount_entry_on_relative_rootfs(struct mntent *mntent, > > - const char *rootfs) > > + const struct lxc_rootfs *rootfs) > > { > > char path[MAXPATHLEN]; > > int ret; > > > > /* relative to root mount point */ > > - ret = snprintf(path, sizeof(path), "%s/%s", rootfs, mntent->mnt_dir); > > + ret = snprintf(path, sizeof(path), "%s/%s", rootfs->mount, > > mntent->mnt_dir); > > if (ret >= sizeof(path)) { > > ERROR("path name too long"); > > return -1; > > @@ -1961,7 +2099,7 @@ static int mount_file_entries(const struct lxc_rootfs > > *rootfs, FILE *file, > > /* We have a separate root, mounts are relative to it */ > > if (mntent.mnt_dir[0] != '/') { > > if (mount_entry_on_relative_rootfs(&mntent, > > - rootfs->mount)) > > + rootfs)) > > goto out; > > continue; > > } > > -- > > 2.6.1 > > > _______________________________________________ > lxc-devel mailing list > [email protected] > http://lists.linuxcontainers.org/listinfo/lxc-devel _______________________________________________ lxc-devel mailing list [email protected] http://lists.linuxcontainers.org/listinfo/lxc-devel
