This (together with the right unit files) is needed in the initramfs in order to natively support mounting /usr (and friends) from the initramfs.
The concept of /etc/fstab.sys is taken from dracut, but might be used elsewhere too. The idea should be that /etc/fstab.sys should contain all filesystems containing "system resources" needed by early boot (i.e. fs' that cannot be mounted or unmounted by the real init). The canonical example would be /usr, but one could imagine also keeping /usr/local or other subdirectories on separate partitions. Notably, /etc (obviously) cannot be mounted from fstab.sys, but must still reside on the rootfs. The way it is meant to work is: * wait for sysroot.mount to be mounted * do a daemon-reload to generate sysroot-usr.mount from /sysroot/etc/fstab.sys * wait for sysroot-usr.mount to be mounted * switch-root Two alternatives were considered, but decided against: * configure usr= on the kernel commandline in the same way as root= is. However, this would be restricted to only the /usr mountpoint, and the kernelcommandline is crowded enough as it is, so it seems more reasonable to store the configuration in /etc (as we can). Moreover, this logic would allow us to use more configuration sources from /etc in the future should that be necessary. * configure the 'sys-mounts' in /etc/fstab. This would require a heuristic to decide which mounts sohuld be taken care of by the initramfs and which to be taken care of by the real init. I could not come up with a non-hacky way of doing that. Perhaps there is use-case for mounting with one set of options in the initrd and remounting with a different set of options in the real init (like can be done for the rootfs)? Keeping everything in fstab would make that impossible. Cc: Harald Hoyer <[email protected]> Cc: Dave Reisner <[email protected]> --- src/fstab-generator/fstab-generator.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/src/fstab-generator/fstab-generator.c b/src/fstab-generator/fstab-generator.c index bfedded..05833ba 100644 --- a/src/fstab-generator/fstab-generator.c +++ b/src/fstab-generator/fstab-generator.c @@ -344,13 +344,14 @@ static int add_mount(const char *what, const char *where, const char *type, cons fprintf(f, "# Automatically generated by systemd-fstab-generator\n\n" "[Unit]\n" - "SourcePath=/etc/fstab\n" + "SourcePath=%s\n" "DefaultDependencies=no\n" "Conflicts=" SPECIAL_UMOUNT_TARGET "\n" "Before=" SPECIAL_UMOUNT_TARGET " %s\n" "\n" "[Automount]\n" "Where=%s\n", + source, post, where); @@ -375,18 +376,20 @@ static int add_mount(const char *what, const char *where, const char *type, cons return 0; } -static int parse_fstab(void) { +static int parse_fstab(const char *prefix, const char *postfix) { FILE *f; + _cleanup_free_ char *fstab_path = NULL; int r = 0; struct mntent *me; errno = 0; - f = setmntent("/etc/fstab", "r"); + fstab_path = strjoin(prefix, "/etc/fstab", postfix, NULL); + f = setmntent(fstab_path, "r"); if (!f) { if (errno == ENOENT) return 0; - log_error("Failed to open /etc/fstab: %m"); + log_error("Failed to open %s/etc/fstab%s: %m", prefix, postfix); return -errno; } @@ -395,7 +398,7 @@ static int parse_fstab(void) { int k; what = fstab_node_to_udev_node(me->mnt_fsname); - where = strdup(me->mnt_dir); + where = strjoin(prefix, me->mnt_dir, NULL); if (!what || !where) { r = log_oom(); goto finish; @@ -422,7 +425,7 @@ static int parse_fstab(void) { k = add_mount(what, where, me->mnt_type, me->mnt_opts, me->mnt_passno, false, noauto, nofail, automount, isbind, isnetwork, - "/etc/fstab"); + fstab_path); } if (k < 0) @@ -557,7 +560,7 @@ static int parse_proc_cmdline(void) { } int main(int argc, char *argv[]) { - int r, k = 0; + int r = 0, k, l = 0; if (argc > 1 && argc != 4) { log_error("This program takes three or no arguments."); @@ -577,12 +580,15 @@ int main(int argc, char *argv[]) { return EXIT_FAILURE; if (in_initrd()) - k = parse_new_root_from_proc_cmdline(); + r = parse_new_root_from_proc_cmdline(); if (!arg_enabled) - return EXIT_SUCCESS; + return (r < 0) ? EXIT_FAILURE : EXIT_SUCCESS; - r = parse_fstab(); + k = parse_fstab("", ""); - return (r < 0) || (k < 0) ? EXIT_FAILURE : EXIT_SUCCESS; + if (in_initrd()) + l = parse_fstab("/sysroot", ".sys"); + + return (r < 0) || (k < 0) || (l < 0) ? EXIT_FAILURE : EXIT_SUCCESS; } -- 1.8.1.4 _______________________________________________ systemd-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/systemd-devel
