• Hidehiro Kawai's avatar
    jbd: fix error handling for checkpoint io · 4afe9785
    Hidehiro Kawai authored
    When a checkpointing IO fails, current JBD code doesn't check the error
    and continue journaling.  This means latest metadata can be lost from both
    the journal and filesystem.
    This patch leaves the failed metadata blocks in the journal space and
    aborts journaling in the case of log_do_checkpoint().  To achieve this, we
    need to do:
    1. don't remove the failed buffer from the checkpoint list where in
       the case of __try_to_free_cp_buf() because it may be released or
       overwritten by a later transaction
    2. log_do_checkpoint() is the last chance, remove the failed buffer
       from the checkpoint list and abort the journal
    3. when checkpointing fails, don't update the journal super block to
       prevent the journaled contents from being cleaned.  For safety,
       don't update j_tail and j_tail_sequence either
    4. when checkpointing fails, notify this error to the ext3 layer so
       that ext3 don't clear the needs_recovery flag, otherwise the
       journaled contents are ignored and cleaned in the recovery phase
    5. if the recovery fails, keep the needs_recovery flag
    6. prevent cleanup_journal_tail() from being called between
       __journal_drop_transaction() and journal_abort() (a race issue
       between journal_flush() and __log_wait_for_space()
    Signed-off-by: default avatarHidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
    Acked-by: default avatarJan Kara <jack@suse.cz>
    Cc: <linux-ext4@vger.kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
jbd.h 32.3 KB