On 2018-01-03 22:54, Hauke Mehrtens wrote:
On 12/15/2017 03:10 PM, Roman Yeryomin wrote:
There is a race between `cp -a /tmp/root/* /rom/overlay` from
libfstools/overlay.c and a process creating new file(s) before
pivot(/rom, /mnt) occured.
That is a process can create a file and it will not be copied.
To workaround this, do additional copy after jffs2 is ready.
This doesn't completely solve the problem but since there
was no other fix provided since original RFC [1], it is better
than nothiing.
[1]
https://www.mail-archive.com/openwrt-devel@lists.openwrt.org/msg38218.html
Signed-off-by: Roman Yeryomin <ro...@advem.lv>
---
libfstools/overlay.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/libfstools/overlay.c b/libfstools/overlay.c
index 7ada5ff..8423a57 100644
--- a/libfstools/overlay.c
+++ b/libfstools/overlay.c
@@ -243,6 +243,10 @@ jffs2_switch(struct volume *v)
ULOG_INFO("performing overlay whiteout\n");
umount2("/tmp/root", MNT_DETACH);
foreachdir("/overlay/", handle_whiteout);
+
+ /* try hard to be in sync */
+ ULOG_INFO("syncronizing overlay\n");
+ system("cp -a /tmp/root/upper/* / 2>/dev/null");
break;
case FS_EXT4:
This patch causes the following compile problem when compiled with
glibc
on x86:
[ 50%] Building C object CMakeFiles/fstools.dir/libfstools/overlay.c.o
/home/hauke/openwrt/lede/build_dir/target-x86_64_glibc/fstools-2018-01-02-11efbf3b/libfstools/overlay.c:
In function 'jffs2_switch':
/home/hauke/openwrt/lede/build_dir/target-x86_64_glibc/fstools-2018-01-02-11efbf3b/libfstools/overlay.c:249:3:
warning: ignoring return value of 'system', declared with attribute
warn_unused_result [-Wunused-result]
system("cp -a /tmp/root/upper/* / 2>/dev/null");
^
/home/hauke/openwrt/lede/build_dir/target-x86_64_glibc/fstools-2018-01-02-11efbf3b/libfstools/overlay.c:
At top level:
cc1: error: unrecognized command line option '-Wno-format-truncation'
[-Werror]
cc1: all warnings being treated as errors
CMakeFiles/fstools.dir/build.make:110: recipe for target
'CMakeFiles/fstools.dir/libfstools/overlay.c.o' failed
Patch sent to list, thanks!
Regards,
Roman
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