Hi all,
I'm debugging an issue on my platform. In short, I can corrupt an ext4
filesystem on one partition by writing a file on a different one. I'm
suspecting something is off either with my partition table or filesystem
parameters, but I'm such an ext4 beginner that I thought I'd start here
to get some help in where to look.
If I run this (which writes a relatively large file to partition 12):
dd if=/dev/zero of=/cache/goingtodie bs=4096 count=120000
Then (after rebooting) I'll get an ext4 error like this on partition 13:
EXT4-fs error (device mmcblk0p13): ext4_readdir:214: inode
#102545: block 426479: comm er.ServerThread:
path /data/app-private: bad entry in directory: rec_len is
smaller than minimal - offset=0(0), inode=0, rec_len=0, na0
My android system runs a slightly modified 3.0.31 kernel with 4GB eMMC
as the block device. My partition table is set up as such (located in
the first 34 blocks):
lba size = 512
lba_start partition_size name
========= ====================== ==============
34 97280( 95K) environment
224 16384( 16K) crypto
256 393216( 384K) xloader
1024 524288( 512K) bootloader
2048 524288( 512K) device_info
3072 524288( 512K) bootloader2
4096 524288( 512K) misc
5120 8388608( 8M) recovery
21504 8388608( 8M) boot
37888 16777216( 16M) efs
70656 1073741824( 1024M) system
2167808 536870912( 512M) cache
3216384 2195193856( 2093M) userdata
========= ====================== ==============
The two filesystems in question are the cache and userdata partitions.
These are created with the following make_ext4fs[1] commands and then
flashed to eMMC:
% make_ext4fs -s -L cache -l 536870912 cache.img cache
Creating filesystem with parameters:
Size: 536870912
Block size: 4096
Blocks per group: 32768
Inodes per group: 8192
Inode size: 256
Journal blocks: 2048
Label: cache
Blocks: 131072
Block groups: 4
Reserved block group size: 31
Created filesystem with 11/32768 inodes and 4206/131072 blocks
% make_ext4fs -s -l 2143744K -a data userdata.img data/
Creating filesystem with parameters:
Size: 2195193856
Block size: 4096
Blocks per group: 32768
Inodes per group: 7888
Inode size: 256
Journal blocks: 8374
Label:
Blocks: 535936
Block groups: 17
Reserved block group size: 135
Created filesystem with 11/134096 inodes and 17614/535936 blocks
Any help is very much appreciated. Does anyone see anything amiss, or
that I should try looking into? If there's any more information that's
needed just let me know. Or if you think there's a better mailing list
for me to take this to, I can do that too.
[1]:
https://android.googlesource.com/platform/system/extras/+/fb109b894a5fc2891e49ec8e81c0dda171b45b7f/ext4_utils/make_ext4fs_main.c
--
Devrin Talen <dct23@xxxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
