On Thu, Jul 20, 2017 at 4:27 PM, Eric Sandeen [off-list ref] wrote:

On 07/20/2017 02:52 AM, Stefan Ring wrote:

quoted

On Thu, Jul 20, 2017 at 12:00 AM, Eric Sandeen [off-list ref] wrote:

quoted

ok, that shoulda worked... I wonder how to debug this, if you can't
legally share the problematic image with me to investigate...

I put a lot of effort into selectively zeroing out unused portions
of metablocks a couple years back, I am surprised that this much remains.

I wonder if something regressed ...

I will try if I can find out which code paths lead to the content
being dumped out.

Perhaps you could send xfs_info output and offsets of the "safe" strings,
and maybe look at block or sector boundaries of the blocks containing
those "safe" strings to identify magic numbers which would identify
the metadata types ...

Ok,

I'm using the for-next branch now (0602fbe880) and inserted something
like this so I can set a breakpoint on my_break.

--- a/db/metadump.c
+++ b/db/metadump.c

@@ -169,6 +169,10 @@ write_index(void)
        return 0;
 }

+void my_break()
+{
+}
+
 /*
  * Return 0 for success, -errno for failure.
  */

@@ -184,6 +188,8 @@ write_buf_segment(
        for (i = 0; i < len; i++, off++, data += BBSIZE) {
                block_index[cur_index] = cpu_to_be64(off);
                memcpy(&block_buffer[cur_index << BBSHIFT], data, BBSIZE);
+               if (memmem(data, BBSIZE, "_mkstemp_inner", 14))
+                       my_break();
                if (++cur_index == num_indices) {
                        ret = write_index();
                        if (ret)

The backtraces are quite similar except for the "stray filenames"
case. I've repeated the exercise for every snippet I've highlighted in
the previous e-mail (in the same order):

"MasterShellCommand"
#0  my_break () at metadump.c:174
#1  0x000000000041e2a6 in write_buf_segment (data=0xe26c00 "XD2F",
off=134667936, len=8) at metadump.c:192
#2  0x000000000041e3d3 in write_buf (buf=0x7fd7b0) at metadump.c:238
#3  0x000000000042163d in process_single_fsb_objects (o=16777216,
s=16833492, c=1, btype=TYP_DIR2, last=16777217)
    at metadump.c:1829
#4  0x0000000000421cdd in process_bmbt_reclist (rp=0xdf5628,
numrecs=34, btype=TYP_DIR2) at metadump.c:1997
#5  0x0000000000421e22 in scanfunc_bmap (block=0xdf5400, agno=0,
agbno=57273, level=0, btype=TYP_BMAPBTD,
    arg=0x7fffffffd994) at metadump.c:2031
#6  0x000000000041eb6c in scan_btree (agno=0, agbno=57273, level=1,
btype=TYP_BMAPBTD, arg=0x7fffffffd994,
    func=0x421d40 <scanfunc_bmap>) at metadump.c:427
#7  0x000000000042236b in process_btinode (dip=0xdd3700,
itype=TYP_DIR2) at metadump.c:2125
#8  0x000000000042276f in process_inode_data (dip=0xdd3700,
itype=TYP_DIR2) at metadump.c:2186
#9  0x00000000004228b0 in process_inode (agno=0, agino=900491,
dip=0xdd3700, free_inode=false) at metadump.c:2231
#10 0x0000000000422e15 in copy_inode_chunk (agno=0, rp=0xafee40) at
metadump.c:2373
#11 0x0000000000422fd5 in scanfunc_ino (block=0xafea00, agno=0,
agbno=25, level=0, btype=TYP_INOBT, arg=0x7fffffffdc44)
    at metadump.c:2433
#12 0x000000000041eb6c in scan_btree (agno=0, agbno=25, level=1,
btype=TYP_INOBT, arg=0x7fffffffdc44,
    func=0x422ecd <scanfunc_ino>) at metadump.c:427
#13 0x000000000042317e in scanfunc_ino (block=0x78d200, agno=0,
agbno=63095, level=1, btype=TYP_INOBT,
    arg=0x7fffffffdc44) at metadump.c:2456
#14 0x000000000041eb6c in scan_btree (agno=0, agbno=63095, level=2,
btype=TYP_INOBT, arg=0x7fffffffdc44,
    func=0x422ecd <scanfunc_ino>) at metadump.c:427
#15 0x0000000000423274 in copy_inodes (agno=0, agi=0x6cd400) at metadump.c:2489
#16 0x00000000004238b3 in scan_ag (agno=0) at metadump.c:2613
#17 0x00000000004244be in metadump_f (argc=5, argv=0x6cd310) at metadump.c:2895
#18 0x000000000041a544 in main (argc=<value optimized out>,
argv=<value optimized out>) at init.c:207


"MANPATH_MAP"
#0  my_break () at metadump.c:174
#1  0x000000000041e2a6 in write_buf_segment (
    data=0xe38000 " nearby files and
directories.\n#\nMANPATH_MAP\t/bin\t\t\t/usr/share/man\nMANPATH_MAP\t/sbin\t\t\t/usr/share/man\nMANPATH_MAP\t/usr/bin\t\t/usr/share/man\nMANPATH_MAP\t/usr/sbin\t\t/usr/share/man\nMANPATH_MAP\t/usr/local/"...,
off=67559158, len=8) at metadump.c:192
#2  0x000000000041e3d3 in write_buf (buf=0x7fd750) at metadump.c:238
#3  0x000000000042163d in process_single_fsb_objects (o=8388608,
s=8444894, c=1, btype=TYP_DIR2, last=8388609)
    at metadump.c:1829
#4  0x0000000000421cdd in process_bmbt_reclist (rp=0xe2ff84,
numrecs=3, btype=TYP_DIR2) at metadump.c:1997
#5  0x00000000004226db in process_exinode (dip=0xe2ff00,
itype=TYP_DIR2) at metadump.c:2157
#6  0x000000000042275c in process_inode_data (dip=0xe2ff00,
itype=TYP_DIR2) at metadump.c:2183
#7  0x00000000004228b0 in process_inode (agno=0, agino=900611,
dip=0xe2ff00, free_inode=false) at metadump.c:2231
#8  0x0000000000422e15 in copy_inode_chunk (agno=0, rp=0xafee50) at
metadump.c:2373
#9  0x0000000000422fd5 in scanfunc_ino (block=0xafea00, agno=0,
agbno=25, level=0, btype=TYP_INOBT, arg=0x7fffffffdc44)
    at metadump.c:2433
#10 0x000000000041eb6c in scan_btree (agno=0, agbno=25, level=1,
btype=TYP_INOBT, arg=0x7fffffffdc44,
    func=0x422ecd <scanfunc_ino>) at metadump.c:427
#11 0x000000000042317e in scanfunc_ino (block=0x78d200, agno=0,
agbno=63095, level=1, btype=TYP_INOBT,
    arg=0x7fffffffdc44) at metadump.c:2456
#12 0x000000000041eb6c in scan_btree (agno=0, agbno=63095, level=2,
btype=TYP_INOBT, arg=0x7fffffffdc44,
    func=0x422ecd <scanfunc_ino>) at metadump.c:427
#13 0x0000000000423274 in copy_inodes (agno=0, agi=0x6cd400) at metadump.c:2489
#14 0x00000000004238b3 in scan_ag (agno=0) at metadump.c:2613
#15 0x00000000004244be in metadump_f (argc=5, argv=0x6cd310) at metadump.c:2895
#16 0x000000000041a544 in main (argc=<value optimized out>,
argv=<value optimized out>) at init.c:207


"RPM-GPG-KEY-beta"
#0  my_break () at metadump.c:174
#1  0x000000000041e2a6 in write_buf_segment (data=0xf1b600
"INA\375\002\002", off=451728, len=32) at metadump.c:192
#2  0x000000000041e3d3 in write_buf (buf=0x7fd6f0) at metadump.c:238
#3  0x0000000000422e4b in copy_inode_chunk (agno=0, rp=0xafef80) at
metadump.c:2380
#4  0x0000000000422fd5 in scanfunc_ino (block=0xafea00, agno=0,
agbno=25, level=0, btype=TYP_INOBT, arg=0x7fffffffdc44)
    at metadump.c:2433
#5  0x000000000041eb6c in scan_btree (agno=0, agbno=25, level=1,
btype=TYP_INOBT, arg=0x7fffffffdc44,
    func=0x422ecd <scanfunc_ino>) at metadump.c:427
#6  0x000000000042317e in scanfunc_ino (block=0x78d200, agno=0,
agbno=63095, level=1, btype=TYP_INOBT,
    arg=0x7fffffffdc44) at metadump.c:2456
#7  0x000000000041eb6c in scan_btree (agno=0, agbno=63095, level=2,
btype=TYP_INOBT, arg=0x7fffffffdc44,
    func=0x422ecd <scanfunc_ino>) at metadump.c:427
#8  0x0000000000423274 in copy_inodes (agno=0, agi=0x6cd400) at metadump.c:2489
#9  0x00000000004238b3 in scan_ag (agno=0) at metadump.c:2613
#10 0x00000000004244be in metadump_f (argc=5, argv=0x6cd310) at metadump.c:2895
#11 0x000000000041a544 in main (argc=<value optimized out>,
argv=<value optimized out>) at init.c:207


"_mkstemp_inner"
#0  my_break () at metadump.c:174
#1  0x000000000041e2a6 in write_buf_segment (
    data=0x1388e00 "le.py\", line 300, in mkstemp\n2015-04-15 16:25:34
(140466167215872)     return _mkstemp_inner(dir, prefix, suffix,
flags)\n2015-04-15 16:25:34 (140466167215872)   File
\"/opt/vtse/lib/python2.7/tempfile."...,
    off=67568243, len=8) at metadump.c:192
#2  0x000000000041e3d3 in write_buf (buf=0x7fd750) at metadump.c:238
#3  0x000000000042163d in process_single_fsb_objects (o=8388608,
s=8446030, c=1, btype=TYP_DIR2, last=8388609)
    at metadump.c:1829
#4  0x0000000000421cdd in process_bmbt_reclist (rp=0x1382b84,
numrecs=3, btype=TYP_DIR2) at metadump.c:1997
#5  0x00000000004226db in process_exinode (dip=0x1382b00,
itype=TYP_DIR2) at metadump.c:2157
#6  0x000000000042275c in process_inode_data (dip=0x1382b00,
itype=TYP_DIR2) at metadump.c:2183
#7  0x00000000004228b0 in process_inode (agno=0, agino=918921,
dip=0x1382b00, free_inode=false) at metadump.c:2231
#8  0x0000000000422e15 in copy_inode_chunk (agno=0, rp=0x117bbd0) at
metadump.c:2373
#9  0x0000000000422fd5 in scanfunc_ino (block=0x117b800, agno=0,
agbno=57301, level=0, btype=TYP_INOBT,
    arg=0x7fffffffdc44) at metadump.c:2433
#10 0x000000000041eb6c in scan_btree (agno=0, agbno=57301, level=1,
btype=TYP_INOBT, arg=0x7fffffffdc44,
    func=0x422ecd <scanfunc_ino>) at metadump.c:427
#11 0x000000000042317e in scanfunc_ino (block=0x78d200, agno=0,
agbno=63095, level=1, btype=TYP_INOBT,
    arg=0x7fffffffdc44) at metadump.c:2456
#12 0x000000000041eb6c in scan_btree (agno=0, agbno=63095, level=2,
btype=TYP_INOBT, arg=0x7fffffffdc44,
    func=0x422ecd <scanfunc_ino>) at metadump.c:427
#13 0x0000000000423274 in copy_inodes (agno=0, agi=0x6cd400) at metadump.c:2489
#14 0x00000000004238b3 in scan_ag (agno=0) at metadump.c:2613
#15 0x00000000004244be in metadump_f (argc=5, argv=0x6cd310) at metadump.c:2895
#16 0x000000000041a544 in main (argc=<value optimized out>,
argv=<value optimized out>) at init.c:207

SVG
#0  my_break () at metadump.c:174
#1  0x000000000041e2a6 in write_buf_segment (data=0x132f400 "",
off=67567736, len=8) at metadump.c:192
#2  0x000000000041e3d3 in write_buf (buf=0x7fd750) at metadump.c:238
#3  0x000000000042163d in process_single_fsb_objects (o=8388608,
s=8445967, c=1, btype=TYP_DIR2, last=8388609)
    at metadump.c:1829
#4  0x0000000000421cdd in process_bmbt_reclist (rp=0x132b874,
numrecs=2, btype=TYP_DIR2) at metadump.c:1997
#5  0x00000000004226db in process_exinode (dip=0x132b800,
itype=TYP_DIR2) at metadump.c:2157
#6  0x000000000042275c in process_inode_data (dip=0x132b800,
itype=TYP_DIR2) at metadump.c:2183
#7  0x00000000004228b0 in process_inode (agno=0, agino=917784,
dip=0x132b800, free_inode=false) at metadump.c:2231
#8  0x0000000000422e15 in copy_inode_chunk (agno=0, rp=0x117bb50) at
metadump.c:2373
#9  0x0000000000422fd5 in scanfunc_ino (block=0x117b800, agno=0,
agbno=57301, level=0, btype=TYP_INOBT,
    arg=0x7fffffffdc44) at metadump.c:2433
#10 0x000000000041eb6c in scan_btree (agno=0, agbno=57301, level=1,
btype=TYP_INOBT, arg=0x7fffffffdc44,
    func=0x422ecd <scanfunc_ino>) at metadump.c:427
#11 0x000000000042317e in scanfunc_ino (block=0x78d200, agno=0,
agbno=63095, level=1, btype=TYP_INOBT,
    arg=0x7fffffffdc44) at metadump.c:2456
#12 0x000000000041eb6c in scan_btree (agno=0, agbno=63095, level=2,
btype=TYP_INOBT, arg=0x7fffffffdc44,
    func=0x422ecd <scanfunc_ino>) at metadump.c:427
#13 0x0000000000423274 in copy_inodes (agno=0, agi=0x6cd400) at metadump.c:2489
#14 0x00000000004238b3 in scan_ag (agno=0) at metadump.c:2613
#15 0x00000000004244be in metadump_f (argc=5, argv=0x6cd310) at metadump.c:2895
#16 0x000000000041a544 in main (argc=<value optimized out>,
argv=<value optimized out>) at init.c:207


Is this helpful?

Now I also know that I have proceeded to inode 21440 of 11857664 with
my visual inspection, so it is a good thing that I stopped early ;).