Christoph Anton Mitterer wrote on 2015/11/22 07:56 +0100:
Hey Qu.
On Sun, 2015-11-22 at 10:04 +0800, Qu Wenruo wrote:
If any of you can recompile btrfs-progs and use gdb to debug it,
would
anyone please to investigate where did the wrong_chunk_type is set?
It is in the function check_extent_type():
Not 100% what you want... AFAIU, you just want to see whether that line
is reached?
If didn't re-compile but used the btrfs-tools-dbg package, but I guess
that should do.
In the debian version that line seems to be at:
4374
4375 /* Check if the type of extent matches with its chunk */
4376 static void check_extent_type(struct extent_record *rec)
4377 {
...
4419 bg_type = BTRFS_BLOCK_GROUP_METADATA;
4420 if (!(bg_cache->flags & bg_type))
4421 rec->wrong_chunk_type = 1;
4422 }
4423 }
Running:
# gdb btrfs
(gdb) dir /root/btrfs-tools-4.3
Source directories searched: /root/btrfs-tools-4.3:$cdir:$cwd
(gdb) break cmds-check.c:4421
Breakpoint 1 at 0x41d859: file cmds-check.c, line 4421.
(gdb) run check /dev/mapper/data-b
Starting program: /bin/btrfs check /dev/mapper/data-b
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
... in fact reaches that breakpoint:
Breakpoint 1, check_extent_type (rec=rec@entry=0x884290) at cmds-check.c:4423
4423 }
Normally you can use -dbg package, but as you experienced, a lot of
reasons like optimization from compiler can cause such situation.
That's why I recommended to compile the package from scratch.
And if you want to compile, it's also recommended to disable unrelated
component by disabling document(needs xmlto and ascii) and convert(needs
a lot of ext2 related headers).
"./configure --disable-convert --disable-documentation" should do the trick.
Also, you won't want compiler to do extra optimization, so after
configuration, you'd better edit Makefile and change optimization level
to 0, by changing the "-O1" (o and one) to "-O0" (o and zero) of CFLAGS.
Then make, compiler will complain about the optimization level as some
headers need it, but that's OK and won't cause anything wrong.
After make, you won't need to install the btrfs-progs, you can just use
gdb to debug local ./btrfsck and add new breakpoints to do the trick.
Thanks,
Qu
... but the error message ("bad extent [5993525264384, 5993525280768),
type mismatch with chunk") doesn't seem to be printed at that stage...
If I continue, it goes for a while:
Breakpoint 1, check_extent_type (rec=rec@entry=0x884290) at cmds-check.c:4423
4423 }
(gdb) cont 100000
Will ignore next 99999 crossings of breakpoint 1. Continuing.
and so on for at least several million crossings... I then removed the
breakpoint and after a longer while the usual error messages came up.
Does that help?
Chris.
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