Am 29.06.2016 um 12:21 schrieb John Crispin: > > > On 29/06/2016 12:11, Josua Mayer wrote: >> Hi John, >> >> thansk for taking a look. I actually sent it this way by intention, >> looking to get in touch with someone who had the original bug. >> >> Am 29.06.2016 um 08:30 schrieb John Crispin: >>> Hi, >>> >>> the patch is an attachement making inline commenting impossible. please >>> send patches inline >> From 59a8fa6d7490ba3da76aec710a1beb241ffaa089 Mon Sep 17 00:00:00 2001 >> From: Josua Mayer <josua.maye...@gmail.com> >> Date: Thu, 16 Jun 2016 18:35:30 +0200 >> Subject: [PATCH 2/4] mount_root: Don't mount ext4 rootfs twice >> >> When there is a) no rootfs_data overlay partition, >> and b) /dev/root points to an ext4 partition >> the partition would be mounted twice, once as / and then as /overlay. >> The essence of this change is to return before mounting /overlay, >> if /dev/root has been mounted as /. >>> >> Signed-off-by: Josua Mayer <josua.maye...@gmail.com> >> --- >> mount_root.c | 40 ++++++++++++++++++++++++++++++---------- >> 1 file changed, 30 insertions(+), 10 deletions(-) >> >> diff --git a/mount_root.c b/mount_root.c >> index 608ce5d..13e5772 100644 >> --- a/mount_root.c >> +++ b/mount_root.c >> @@ -37,25 +37,45 @@ start(int argc, char *argv[1]) >> if (!getenv("PREINIT") && stat("/tmp/.preinit", &s)) >> return -1; >> >> + /* >> + * When the default overlay partition name rootfs_data can not be found, >> + * fall back to the special /dev/root device. >> + */ >> if (!data) { >> root = volume_find("rootfs"); >> volume_init(root); >> + >> + // mount /dev/root at / >> ULOG_NOTE("mounting /dev/root\n"); >> mount("/dev/root", "/", NULL, MS_NOATIME | MS_REMOUNT, 0); >> - } >> >> - /* >> - * Before trying to mount and use "rootfs_data" let's check if there is >> - * extroot configured. Following call will handle reading config from >> - * the "rootfs_data" on its own. >> - */ >> - extroot_prefix = ""; >> - if (!mount_extroot()) { >> - ULOG_NOTE("switched to extroot\n"); >> + /* >> + * Now that / has been mounted, and there is no overlay device, >> + * see if extroot is configured. >> + * >> + * The following call will handle reading configuration from >> + * rootfs on its own. >> + */ >> + extroot_prefix = ""; >> + if (!mount_extroot()) { >> + ULOG_NOTE("switched to extroot\n"); >> + /* >> + * extroot succeeded mounting an overlay partition, >> return. >> + */ >> + return 0; >> + } >> + >> + /* >> + * Even if extroot was not configured, considering that no >> overlay >> + * partition was found, and / was mounted, return now. >> + */ >> return 0; >> } >> >> - /* There isn't extroot, so just try to mount "rootfs_data" */ >> + /* >> + * neither /dev/root nor extroot were used. >> + * Attempt to mount the overlay partition. >> + */ >> switch (volume_identify(data)) { >> case FS_NONE: >> ULOG_WARN("no usable overlay filesystem found, using tmpfs >> overlay\n"); >> > > derived from looking at the patch. as the patch is not inline i am not > able to actually import it locally so i can only judge it by looking at it. > > after applying your patch, mount_extroot() would be hidden behind a > if(!data) {} which means that it will only ever be called if there is no > rootfs_data That is only partially right. Like I pointed out, it is called inside mount_overlay(). If there is a way to fix this, I need to understand what should happen: code path before my patch: data = volume_find("rootfs_data"); if (!data) {/* mount /dev/root as / */} mount_extroot() switch (volume_identify(data))
>From this artificial trace, I extracted these runtime conditions for extroot: 1. rootfs_data exists but not mounted yet 2. rootfs_data does not exist and /dev/root mounted as / I then guessed that mount_extroot only makes sense when there is an overlay partition, or the read-write rootfs mounted in order to have its configuration available. So my guess was: if overlay isnt mounted yet but will be later, no point in executing mount_extroot. Especially considering it will be inherently called from the call to mount_overlay thats occuring later on. > > John > _______________________________________________ Lede-dev mailing list Lede-dev@lists.infradead.org http://lists.infradead.org/mailman/listinfo/lede-dev