#36 mksquashfs v4.0 silently creates corrupt filesystem images

closed
nobody
None
5
2010-07-16
2009-10-15
No

I have an automated system that frequently creates squashfs filesystems. Occasionally (about once a week) mksquashfs will produce a squashfs image that is corrupt past a certain point. It's taken me a while to isolate the problem (I didn't expect a bug in mksquashfs so was looking elsewhere for the corruption), but now I'm fairly (99%) confident that I've isolated the problem to mksquashfs. Unfortunately I can't reproduce the problem at will, I can only catch it a little while after it has happened.

Below are two output logs from mksquashfs for almost identical operations (only differences will be the source file times & inode numbers).

Corrupt mksquashfs run:

Parallel mksquashfs: Using 2 processors
Creating 4.0 filesystem on /var/manager/tmp/server-config16669.0/sysconfig, block size 131072.
[=================================================================|] 22/22 100%
Exportable Squashfs 4.0 filesystem, data block size 131072
compressed data, compressed metadata, compressed fragments
duplicates are removed
Filesystem size 30.05 Kbytes (0.03 Mbytes)
36.53% of uncompressed filesystem size (82.26 Kbytes)
Inode table size 465 bytes (0.45 Kbytes)
41.44% of uncompressed inode table size (1122 bytes)
Directory table size 410 bytes (0.40 Kbytes)
57.75% of uncompressed directory table size (710 bytes)
Number of duplicate files found 1
Number of inodes 35
Number of files 23
Number of fragments 1
Number of symbolic links 0
Number of device nodes 0
Number of fifo nodes 0
Number of socket nodes 0
Number of directories 12
Number of ids (unique uids + gids) 1
Number of uids 1
root (0)
Number of gids 1
root (0)

Successful squashfs run:

Parallel mksquashfs: Using 2 processors
Creating 4.0 filesystem on /var/manager/tmp/server-config16669.0/sysconfig, block size 131072.
[===============================================================|] 381/381 100%
Exportable Squashfs 4.0 filesystem, data block size 131072
compressed data, compressed metadata, compressed fragments
duplicates are removed
Filesystem size 585.93 Kbytes (0.57 Mbytes)
33.04% of uncompressed filesystem size (1773.48 Kbytes)
Inode table size 4962 bytes (4.85 Kbytes)
33.15% of uncompressed inode table size (14968 bytes)
Directory table size 4837 bytes (4.72 Kbytes)
42.25% of uncompressed directory table size (11449 bytes)
Number of duplicate files found 90
Number of inodes 467
Number of files 388
Number of fragments 10
Number of symbolic links 0
Number of device nodes 0
Number of fifo nodes 0
Number of socket nodes 0
Number of directories 79
Number of ids (unique uids + gids) 1
Number of uids 1
root (0)
Number of gids 1
root (0)

The figures from the corrupted run are dramatically wrong from what they should be. The corrupted filesystem image is 572452 bytes, while the correct filesystem image is 597514 bytes.

I can provide the images if required, but would prefer to do so by email.

Discussion

  • Phillip Lougher

    Phillip Lougher - 2010-07-16

    Nobody else has reported this issue, and I have been unable to reproduce it. Therefore closing due to lack of information/reproducibility.

     
  • Phillip Lougher

    Phillip Lougher - 2010-07-16
    • status: open --> closed
     

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