Steven J. Magnani 70f19f5869 udf: Don't corrupt unalloc spacetable when writing it
For a UDF filesystem configured with an Unallocated Space Table,
a filesystem operation that triggers an update to the table results
in on-disk corruption that prevents remounting:

  udf_read_tagged: tag version 0x0000 != 0x0002 || 0x0003, block 274

For example:
  1. Create a filesystem
      $ mkudffs --media-type=hd --blocksize=512 --lvid=BUGTEST \
              --vid=BUGTEST --fsid=BUGTEST --space=unalloctable \
              /dev/mmcblk0

  2. Mount it
      # mount /dev/mmcblk0 /mnt

  3. Create a file
      $ echo "No corruption, please" > /mnt/new.file

  4. Umount
      # umount /mnt

  5. Attempt remount
      # mount /dev/mmcblk0 /mnt

This appears to be a longstanding bug caused by zero-initialization of
the Unallocated Space Entry block buffer and only partial repopulation
of required fields before writing to disk.

Commit 0adfb339fd64 ("udf: Fix unalloc space handling in udf_update_inode")
addressed one such field, but several others are required.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: Jan Kara <jack@suse.com>
2015-07-09 16:38:57 +02:00
..
2015-01-05 11:04:37 +01:00
2014-07-15 22:40:23 +02:00
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2015-05-18 11:23:08 +02:00
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2013-09-24 11:23:33 +02:00