On 09.04.2019 20:08, Kenneth J. Miller wrote:
The extroot mount preparation code for r/w rootfs overlay discovery, and
determining the user-defined /etc/config/fstab location within, would only
discover overlays residing on JFFS2 or UBIFS MTD storage.
This led to attempts at loading the uci fstab configuration without the
required /tmp/overlay directory prefix on devices with a non-MTD r/w
rootfs overlay, and thus failure to find any custom fstab /overlay extroot
entries on PREINIT.
(example: the default openwrt eMMC partition layout on the zyxel nbg6817)
Futher, with UBIFS_EXTROOT enabled (fstools package default), and no MTD
rootfs partitions present, check_extroot would not attempt rootfs
discovery on block devices, such as the ext4 mmcblk rootfs overlay on the
nbg6817.
With this patch:
1) main_extroot now attempts to load uci fstab configuration from an
already mounted overlay, before defaulting to the prefix-less uci
config dir when no MTD rootfs partitions are detected.
2) check_extroot now also attempts to find rootfs partitions on block >
devices when no MTD rootfs partitions are detected.
There were some questions about this old patch on IRC so I took a moment
to review it (finally). It touches some rarely used code and there are
no enough experienced people who remember how it's supposed to work.
block.c | 17 +++++------------
1 file changed, 5 insertions(+), 12 deletions(-)
diff --git a/block.c b/block.c
index 39212d2..3dfc4a5 100644
--- a/block.c
+++ b/block.c
@@ -1301,7 +1301,7 @@ static int find_block_ubi_RO(libubi_t libubi, char *name,
char *part, int plen)
return err;
}
-#else
+#endif
static int find_root_dev(char *buf, int len)
{
@@ -1332,8 +1332,6 @@ static int find_root_dev(char *buf, int len)
return -1;
}
-#endif
-
static int test_fs_support(const char *name)
{
char line[128], *p;
@@ -1363,25 +1361,20 @@ static int check_extroot(char *path)
struct probe_info *pr = NULL;
char devpath[32];
-#ifdef UBIFS_EXTROOT
if (find_block_mtd("\"rootfs\"", devpath, sizeof(devpath))) {
int err = -1;
+#ifdef UBIFS_EXTROOT
libubi_t libubi;
libubi = libubi_open();
err = find_block_ubi_RO(libubi, "rootfs", devpath,
sizeof(devpath));
libubi_close(libubi);
- if (err)
- return -1;
- }
-#else
- if (find_block_mtd("\"rootfs\"", devpath, sizeof(devpath))) {
- if (find_root_dev(devpath, sizeof(devpath))) {
+#endif
+ if (err && find_root_dev(devpath, sizeof(devpath))) {
ULOG_ERR("extroot: unable to determine root device\n");
return -1;
}
}
-#endif
list_for_each_entry(pr, &devices, list) {
if (!strcmp(pr->dev, devpath)) {
@@ -1585,7 +1578,7 @@ static int main_extroot(int argc, char **argv)
}
#endif
- return mount_extroot(NULL);
+ return mount_extroot("/tmp/overlay");
Did you consider consequences of this change? This breaks reading
/etc/config/fstab from "rootfs" partition. You need to handle your
case properly (carefully). Please don't suggest random change that
just happen to work for your scenario.
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