Sorry for not following up on this until now. :( I've been busy and have been using a backup. But I'm still very interested in restoring the btrfs and finding this bug! Let me know if I should refresh any details. Chris Mason wrote: > > In any case changing the partition table shouldn't affect the > > filesystem, right? Also, I changed the partition with the filesystem > > mounted, so the kernel did not start using the new partition table. > > I'd have to repeat the test on this flash card to say for sure. > Deleting then recreating the partition with the FS mounted isn't very > high up on the list of things that get tested often, so my guess is > that's where the problem is. I resized the filesystem, and then changed the partition. However as expected the kernel doesn't really care about the partition change until I reboot, since a partition on the disk was mounted. Do you think this could be a problem still? It seems that the only way there could be a problem is if the resize would not stay within the new smaller size? > > from gdb:ing disk-io.c it seems that zero-bytes are where there's > > supposed to be a root node. So either the root node was destroyed > > (uh-oh?) or code is reading from the wrong place. I don't know > > which is more likely? > > Right, we've got a block full with zeros where they don't belong. > Can you run dump the block contents with gdb please? I'd like to > see if they are all zeros or just offset slightly. That block is all zeros. /tmp/btrfs-progs-unstable $ gdb --args ./btrfs-debug-tree /dev/sdb2 GNU gdb 6.8 Copyright (C) 2008 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "i686-pc-linux-gnu"... (gdb) b read_extent_from_disk Breakpoint 1 at 0x806882d: file extent_io.c, line 671. (gdb) r Starting program: /tmp/btrfs-progs-unstable/btrfs-debug-tree /dev/sdb2 Breakpoint 1, read_extent_from_disk (eb=0x92a0538) at extent_io.c:671 671 ret = pread(eb->fd, eb->data, eb->len, eb->dev_bytenr); (gdb) p eb->dev_bytenr $1 = 20971520 (gdb) c Continuing. Breakpoint 1, read_extent_from_disk (eb=0x92a1588) at extent_io.c:671 671 ret = pread(eb->fd, eb->data, eb->len, eb->dev_bytenr); (gdb) p eb->dev_bytenr $2 = 20987904 (gdb) c Continuing. Breakpoint 1, read_extent_from_disk (eb=0x92a25d8) at extent_io.c:671 671 ret = pread(eb->fd, eb->data, eb->len, eb->dev_bytenr); (gdb) p eb->dev_bytenr $3 = 20983808 (gdb) c Continuing. Breakpoint 1, read_extent_from_disk (eb=0x92a3628) at extent_io.c:671 671 ret = pread(eb->fd, eb->data, eb->len, eb->dev_bytenr); (gdb) p eb->dev_bytenr $4 = 36675878912 (gdb) p eb->len (gdb) c Continuing. Breakpoint 1, read_extent_from_disk (eb=0x92a3628) at extent_io.c:671 671 ret = pread(eb->fd, eb->data, eb->len, eb->dev_bytenr); (gdb) p eb->dev_bytenr $5 = 36944314368 (gdb) c Continuing. btrfs-debug-tree: disk-io.c:739: open_ctree_fd: Assertion `!(!tree_root->node)' failed. Program received signal SIGABRT, Aborted. 0xb78ea424 in __kernel_vsyscall () (gdb) q The program is running. Exit anyway? (y or n) y $ bc <<< 36944314368/4096 9019608 $ dd if=/dev/sdb2 bs=4k skip=9019608 count=1|xxd -a 0000000: 0000 0000 0000 0000 0000 0000 0000 0000 ................ * 0000ff0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 1+0 records in 1+0 records out 4096 bytes (4.1 kB) copied, 0.0035931 s, 1.1 MB/s Nearby blocks are also zero: $ dd if=/dev/sdb2 bs=4k skip=$[9019608-8] count=16|xxd -a 0000000: 0000 0000 0000 0000 0000 0000 0000 0000 ................ * 000fff0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 16+0 records in 16+0 records out 65536 bytes (66 kB) copied, 0.0128077 s, 5.1 MB/s Further back there are some bits: $ dd if=/dev/sdb2 bs=4k skip=$[9019608-17] count=32|xxd -a 0000000: 52a6 7b43 0000 0000 0000 0000 0000 0000 R.{C............ 0000010: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 0000020: c25c f583 2e8c 40b2 8464 175f e314 7a5f .\....@..d._..z_ 0000030: 0070 8c09 0800 0000 0100 0000 0000 0001 .p.............. 0000040: 1538 bb3f eb62 45f5 8956 4728 ca7b fad0 .8.?.bE..VG(.{.. 0000050: 8934 0500 0000 0000 0200 0000 0000 0000 .4.............. 0000060: 4b00 0000 0100 a099 ec07 0000 00a8 0070 K..............p 0000070: 0000 0000 0000 0050 0103 0800 0000 bc32 .......P.......2 0000080: 0500 0000 0000 0090 a6ec 0700 0000 a800 ................ 0000090: 1000 0000 0000 0000 3043 0408 0000 00ed ........0C...... 00000a0: 3205 0000 0000 0000 50ac ec07 0000 00a8 2.......P....... 00000b0: 0020 0000 0000 0000 00d0 4003 0800 0000 . ........@..... 00000c0: be32 0500 0000 0000 0050 b1ec 0700 0000 .2.......P...... 00000d0: a800 0002 0000 0000 0000 506f 0908 0000 ..........Po.... 00000e0: 0084 3405 0000 0000 0000 40be ec07 0000 ..4.......@..... 00000f0: 00a8 0020 0000 0000 0000 0060 4204 0800 ... .......`B... 0000100: 0000 ed32 0500 0000 0000 0030 c1ec 0700 ...2.......0.... 0000110: 0000 a800 1000 0000 0000 0000 8001 0308 ................ 0000120: 0000 00bc 3205 0000 0000 0000 f0c5 ec07 ....2........... 0000130: 0000 00a8 0010 0000 0000 0000 00b0 3d03 ..............=. 0000140: 0800 0000 be32 0500 0000 0000 00d0 c8ec .....2.......... 0000150: 0700 0000 a800 1000 0000 0000 0000 c03d ...............= 0000160: 0308 0000 00be 3205 0000 0000 0000 90cc ......2......... 0000170: ec07 0000 00a8 0010 0000 0000 0000 0020 ............... 0000180: 6f09 0800 0000 8434 0500 0000 0000 0010 o......4........ 0000190: d7ec 0700 0000 a800 1000 0000 0000 0000 ................ 00001a0: f0dd 0108 0000 009b 3205 0000 0000 0000 ........2....... 00001b0: 50e0 ec07 0000 00a8 0030 0000 0000 0000 P........0...... 00001c0: 00f0 cd02 0800 0000 b332 0500 0000 0000 .........2...... 00001d0: 0030 e6ec 0700 0000 a800 3000 0000 0000 .0........0..... 00001e0: 0000 006f 0908 0000 0084 3405 0000 0000 ...o......4..... 00001f0: 0000 40f0 ec07 0000 00a8 00a0 0000 0000 ..@............. 0000200: 0000 0060 7409 0800 0000 8534 0500 0000 ...`t......4.... 0000210: 0000 0000 05ed 0700 0000 a800 1000 0000 ................ 0000220: 0000 0000 d06e 0908 0000 0084 3405 0000 .....n......4... 0000230: 0000 0000 f031 ed07 0000 00a8 0010 0000 .....1.......... 0000240: 0000 0000 00e0 be07 0800 0000 d933 0500 .............3.. 0000250: 0000 0000 0020 52ed 0700 0000 a800 3000 ..... R.......0. 0000260: 0000 0000 0000 60db 0708 0000 00e0 3305 ......`.......3. 0000270: 0000 0000 0000 0068 ef07 0000 00a8 00f0 .......h........ 0000280: 0800 0000 0000 00b0 8c09 0800 0000 8934 ...............4 0000290: 0500 0000 0000 0010 c101 0800 0000 a800 ................ 00002a0: 1000 0000 0000 0000 0044 0908 0000 007b .........D.....{ 00002b0: 3405 0000 0000 0000 d0c6 0108 0000 00a8 4............... 00002c0: 0010 0000 0000 0000 0030 de08 0800 0000 .........0...... 00002d0: 5c34 0500 0000 0000 00c0 c901 0800 0000 \4.............. 00002e0: a800 1000 0000 0000 0000 2014 0508 0000 .......... ..... 00002f0: 0055 3305 0000 0000 0000 90d0 0108 0000 .U3............. 0000300: 00a8 0010 0000 0000 0000 00a0 c003 0800 ................ 0000310: 0000 cc32 0500 0000 0000 0010 d401 0800 ...2............ 0000320: 0000 a800 1000 0000 0000 0000 608b 0908 ............`... 0000330: 0000 0088 3405 0000 0000 0000 50dc 0108 ....4.......P... 0000340: 0000 00a8 0010 0000 0000 0000 0020 4803 ............. H. 0000350: 0800 0000 be32 0500 0000 0000 00e0 e001 .....2.......... 0000360: 0800 0000 a800 1000 0000 0000 0000 109f ................ 0000370: 0708 0000 00d5 3305 0000 0000 0000 70eb ......3.......p. 0000380: 0108 0000 00a8 0010 0000 0000 0000 00a0 ................ 0000390: 8a09 0800 0000 8834 0500 0000 0000 0080 .......4........ 00003a0: 0602 0800 0000 a800 1000 0000 0000 0000 ................ 00003b0: c085 0908 0000 0088 3405 0000 0000 0000 ........4....... 00003c0: b03a 0208 0000 00a8 0010 0000 0000 0000 .:.............. 00003d0: 0070 8a09 0800 0000 8834 0500 0000 0000 .p.......4...... 00003e0: 0020 8502 0800 0000 a800 1000 0000 0000 . .............. 00003f0: 0000 2047 0808 0000 0023 3405 0000 0000 .. G.....#4..... 0000400: 0000 90a6 0208 0000 00a8 0010 0000 0000 ................ 0000410: 0000 00e0 8a09 0800 0000 8834 0500 0000 ...........4.... 0000420: 0000 00c0 d702 0800 0000 a800 1000 0000 ................ 0000430: 0000 0000 3081 0908 0000 0086 3405 0000 ....0.......4... 0000440: 0000 0000 5001 0308 0000 00a8 0010 0000 ....P........... 0000450: 0000 0000 0050 7009 0800 0000 8434 0500 .....Pp......4.. 0000460: 0000 0000 00a0 1203 0800 0000 a800 1000 ................ 0000470: 0000 0000 0000 b03d 0508 0000 005a 3305 .......=.....Z3. 0000480: 0000 0000 0000 7014 0308 0000 00a8 0010 ......p......... 0000490: 0000 0000 0000 0080 7809 0800 0000 8534 ........x......4 00004a0: 0500 0000 0000 0070 1703 0800 0000 a800 .......p........ 00004b0: 1000 0000 0000 0000 806e 0908 0000 0084 .........n...... 00004c0: 3405 0000 0000 0000 5022 0308 0000 00a8 4.......P"...... 00004d0: 0010 0000 0000 0000 00d0 8203 0800 0000 ................ 00004e0: c332 0500 0000 0000 0020 2503 0800 0000 .2....... %..... 00004f0: a800 1000 0000 0000 0000 e078 0908 0000 ...........x.... 0000500: 0085 3405 0000 0000 0000 202e 0308 0000 ..4....... ..... 0000510: 00a8 0010 0000 0000 0000 00a0 4809 0800 ............H... 0000520: 0000 7c34 0500 0000 0000 0070 3103 0800 ..|4.......p1... 0000530: 0000 a800 1000 0000 0000 0000 907f 0908 ................ 0000540: 0000 0086 3405 0000 0000 0000 203d 0308 ....4....... =.. 0000550: 0000 00a8 0010 0000 0000 0000 0070 6f09 .............po. 0000560: 0800 0000 8434 0500 0000 0000 00c0 4503 .....4........E. 0000570: 0800 0000 a800 1000 0000 0000 0000 2078 .............. x 0000580: 0908 0000 0085 3405 0000 0000 0000 b048 ......4........H 0000590: 0308 0000 00a8 0010 0000 0000 0000 00e0 ................ 00005a0: dd08 0800 0000 5c34 0500 0000 0000 0040 ......\4.......@ 00005b0: 4c03 0800 0000 a800 1000 0000 0000 0000 L............... 00005c0: f010 0708 0000 00a0 3305 0000 0000 0000 ........3....... 00005d0: 404f 0308 0000 00a8 0010 0000 0000 0000 @O.............. 00005e0: 0000 c406 0800 0000 9633 0500 0000 0000 .........3...... 00005f0: 0080 5203 0800 0000 a800 1000 0000 0000 ..R............. 0000600: 0000 0000 0000 0000 0000 0000 0000 0000 ................ * 001fff0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 32+0 records in 32+0 records out 131072 bytes (131 kB) copied, 0.0395934 s, 3.3 MB/s But going forward there doesn't seem to be much: $ dd if=/dev/sdb2 bs=4k skip=$[9019608] count=1024|xxd -a 0000000: 0000 0000 0000 0000 0000 0000 0000 0000 ................ * 03ffff0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 1024+0 records in 1024+0 records out 4194304 bytes (4.2 MB) copied, 1.62279 s, 2.6 MB/s //Peter -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
