• Ryusuke Konishi's avatar
    nilfs2: ensure proper cache clearing for gc-inodes · fbb24a3a
    Ryusuke Konishi authored
    A gc-inode is a pseudo inode used to buffer the blocks to be moved by
    garbage collection.
    Block caches of gc-inodes must be cleared every time a garbage collection
    function (nilfs_clean_segments) completes.  Otherwise, stale blocks
    buffered in the caches may be wrongly reused in successive calls of the GC
    For user files, this is not a problem because their gc-inodes are
    distinguished by a checkpoint number as well as an inode number.  They
    never buffer different blocks if either an inode number, a checkpoint
    number, or a block offset differs.
    However, gc-inodes of sufile, cpfile and DAT file can store different data
    for the same block offset.  Thus, the nilfs_clean_segments function can
    move incorrect block for these meta-data files if an old block is cached.
    I found this is really causing meta-data corruption in nilfs.
    This fixes the issue by ensuring cache clear of gc-inodes and resolves
    reported GC problems including checkpoint file corruption, b-tree
    corruption, and the following warning during GC.
      nilfs_palloc_freev: entry number 307234 already freed.
    Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
    Tested-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
    Cc: <stable@vger.kernel.org>	[2.6.37+]
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
gcinode.c 5.65 KB