Hi Bruno,
On Sat, 2020-01-04 at 12:52 +0100, Bruno Pena wrote:
> This patch enables fstools to open read-only MTD partitions, which in
> turn also enables OpenWrt to boot from read-only partitions.
>
> The use of read-only partitions is of special importance for WiFi-
> only
> devices, where a protected read-only recovery image can be used in
> case
> something goes wrong with the main firmware (eg. user gets locked out
> due to bad settings, flash of an unbootable dev firmware, etc).
>
> Signed-off-by: Bruno Pena <brunomp...@gmail.com>
> ---
> libfstools/mtd.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/libfstools/mtd.c b/libfstools/mtd.c
> index 77c71ee..aae633e 100644
> --- a/libfstools/mtd.c
> +++ b/libfstools/mtd.c
> @@ -36,20 +36,31 @@ struct mtd_volume {
>
> static struct driver mtd_driver;
>
> +static int mtd_open_device(const char *dev)
> +{
> + int ret;
> +
> + ret = open(dev, O_RDWR | O_SYNC);
> + if (ret < 0)
> + ret = open(dev, O_RDONLY);
> +
> + return ret;
> +}
> +
> static int mtd_open(const char *mtd, int block)
> {
> FILE *fp;
> char dev[PATH_MAX];
> - int i, ret, flags = O_RDWR | O_SYNC;
> + int i, ret;
>
> if ((fp = fopen("/proc/mtd", "r"))) {
> while (fgets(dev, sizeof(dev), fp)) {
> if (sscanf(dev, "mtd%d:", &i) && strstr(dev,
> mtd)) {
> snprintf(dev, sizeof(dev),
> "/dev/mtd%s/%d", (block ? "block" : ""), i);
> - ret = open(dev, flags);
> + ret = mtd_open_device(dev);
> if (ret < 0) {
> snprintf(dev, sizeof(dev),
> "/dev/mtd%s%d", (block ? "block" : ""), i);
> - ret = open(dev, flags);
> + ret = mtd_open_device(dev);
> }
> fclose(fp);
> return ret;
> @@ -58,7 +69,7 @@ static int mtd_open(const char *mtd, int block)
> fclose(fp);
> }
>
> - return open(mtd, flags);
> + return mtd_open_device(mtd);
> }
>
> static void mtd_volume_close(struct mtd_volume *p)
This patch and related commit de80424f706682e8bba27c60bcd2a9c1b4a5e875
break the jffs erase on my Archer a7 v5.
[ 11.787856] jffs2_scan_eraseblock(): End of filesystem marker found at
0x10000
[ 11.795357] jffs2_build_filesystem(): unlocking the mtd device...
[ 11.795390] done.
[ 11.803771] jffs2_build_filesystem(): erasing all blocks after the end
marker...
[ 11.803781] jffs2: Erase at 0x009e0000 failed immediately: -EROFS. Is
the sector locked?
-------------
[ 13.138841] jffs2: Erase at 0x00010000 failed immediately: -EROFS. Is
the sector locked?
[ 13.147188] done.
[ 13.149202] jffs2: notice: (487) jffs2_build_xattr_subsystem: complete
building xattr subsystem, 0 of xdatum (0 unchecked, 0 orphan) and 0 of xref (0 .
[ 13.165896] mount_root: unable to set filesystem state
[ 13.171443] mount_root: switching to jffs2 overlay
[ 13.201867] overlayfs: failed to resolve '/overlay/upper': -2
[ 13.223939] mount_root: mount failed:
lowerdir=/,upperdir=/overlay/upper,workdir=/overlay/work, options No such device
[ 13.235145] mount_root: switching to jffs2 failed - fallback to
ramoverlay
Verified by reverting de80424f7.
Steve
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