1. 06 Jun, 2011 2 commits
    • Lukas Czerner's avatar
      ext4: Fix max file size and logical block counting of extent format file · f17722f9
      Lukas Czerner authored
      Kazuya Mio reported that he was able to hit BUG_ON(next == lblock)
      in ext4_ext_put_gap_in_cache() while creating a sparse file in extent
      format and fill the tail of file up to its end. We will hit the BUG_ON
      when we write the last block (2^32-1) into the sparse file.
      
      The root cause of the problem lies in the fact that we specifically set
      s_maxbytes so that block at s_maxbytes fit into on-disk extent format,
      which is 32 bit long. However, we are not storing start and end block
      number, but rather start block number and length in blocks. It means
      that in order to cover extent from 0 to EXT_MAX_BLOCK we need
      EXT_MAX_BLOCK+1 to fit into len (because we counting block 0 as well) -
      and it does not.
      
      The only way to fix it without changing the meaning of the struct
      ext4_extent members is, as Kazuya Mio suggested, to lower s_maxbytes
      by one fs block so we can cover the whole extent we can get by the
      on-disk extent format.
      
      Also in many places EXT_MAX_BLOCK is used as length instead of maximum
      logical block number as the name suggests, it is all a bit messy. So
      this commit renames it to EXT_MAX_BLOCKS and change its usage in some
      places to actually be maximum number of blocks in the extent.
      
      The bug which this commit fixes can be reproduced as follows:
      
       dd if=/dev/zero of=/mnt/mp1/file bs=<blocksize> count=1 seek=$((2**32-2))
       sync
       dd if=/dev/zero of=/mnt/mp1/file bs=<blocksize> count=1 seek=$((2**32-1))
      Reported-by: default avatarKazuya Mio <k-mio@sx.jp.nec.com>
      Signed-off-by: default avatarLukas Czerner <lczerner@redhat.com>
      Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
      f17722f9
    • Yongqiang Yang's avatar
      ext4: correct comments for ext4_free_blocks() · 5def1360
      Yongqiang Yang authored
      metadata is not parameter of ext4_free_blocks() any more.
      Signed-off-by: default avatarYongqiang Yang <xiaoqiangnk@gmail.com>
      Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
      5def1360
  2. 30 May, 2011 1 commit
  3. 29 May, 2011 37 commits