On Sat 19-11-11 17:34:29, Yongqiang Yang wrote:
> Currently, we clear revoked flag only when a block is reused. However,
> this can tigger a false journal error. Consider a situation when a block
> is used as a meta block and is deleted(revoked) in ordered mode, then the
> block is allocated as a data block to a file. At this moment, user changes
> the file's journal mode from ordered to journaled and truncates the file.
> The block will be considered re-revoked by journal because it has revoked
> flag still pending from the last transaction and an assertion triggers.
>
> We fix the problem by keeping the revoked status more uptodate - we clear
> revoked flag when switching revoke tables to reflect there is no revoked
> buffers in current transaction any more.
Thanks. Merged into my tree. Will you create the same patch for JBD2 as
well?
Honza
>
> Signed-off-by: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx>
> ---
> fs/jbd/commit.c | 6 ++++++
> fs/jbd/revoke.c | 34 ++++++++++++++++++++++++++++++++++
> include/linux/jbd.h | 1 +
> 3 files changed, 41 insertions(+), 0 deletions(-)
>
> diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
> index 8799207..f2b9a57 100644
> --- a/fs/jbd/commit.c
> +++ b/fs/jbd/commit.c
> @@ -392,6 +392,12 @@ void journal_commit_transaction(journal_t *journal)
> jbd_debug (3, "JBD: commit phase 1\n");
>
> /*
> + * Clear revoked flag to reflect there is no revoked buffers
> + * in the next transaction which is going to be started.
> + */
> + journal_clear_buffer_revoked_flags(journal);
> +
> + /*
> * Switch to a new revoke table.
> */
> journal_switch_revoke_table(journal);
> diff --git a/fs/jbd/revoke.c b/fs/jbd/revoke.c
> index 034eb82..501d363 100644
> --- a/fs/jbd/revoke.c
> +++ b/fs/jbd/revoke.c
> @@ -47,6 +47,10 @@
> * overwriting the new data. We don't even need to clear the revoke
> * bit here.
> *
> + * We cache revoke status of a buffer in the current transaction in b_states
> + * bits. As the name says, revokevalid flag indicates that the cached revoke
> + * status of a buffer is valid and we can rely on the cached status.
> + *
> * Revoke information on buffers is a tri-state value:
> *
> * RevokeValid clear: no cached revoke status, need to look it up
> @@ -474,6 +478,36 @@ int journal_cancel_revoke(handle_t *handle, struct journal_head *jh)
> return did_revoke;
> }
>
> +/*
> + * journal_clear_revoked_flag clears revoked flag of buffers in
> + * revoke table to reflect there is no revoked buffers in the next
> + * transaction which is going to be started.
> + */
> +void journal_clear_buffer_revoked_flags(journal_t *journal)
> +{
> + struct jbd_revoke_table_s *revoke = journal->j_revoke;
> + int i = 0;
> +
> + for (i = 0; i < revoke->hash_size; i++) {
> + struct list_head *hash_list;
> + struct list_head *list_entry;
> + hash_list = &revoke->hash_table[i];
> +
> + list_for_each(list_entry, hash_list) {
> + struct jbd_revoke_record_s *record;
> + struct buffer_head *bh;
> + record = (struct jbd_revoke_record_s *)list_entry;
> + bh = __find_get_block(journal->j_fs_dev,
> + record->blocknr,
> + journal->j_blocksize);
> + if (bh) {
> + clear_buffer_revoked(bh);
> + __brelse(bh);
> + }
> + }
> + }
> +}
> +
> /* journal_switch_revoke table select j_revoke for next transaction
> * we do not want to suspend any processing until all revokes are
> * written -bzzz
> diff --git a/include/linux/jbd.h b/include/linux/jbd.h
> index 0f9f0b6..5aa964e 100644
> --- a/include/linux/jbd.h
> +++ b/include/linux/jbd.h
> @@ -918,6 +918,7 @@ extern int journal_set_revoke(journal_t *, unsigned int, tid_t);
> extern int journal_test_revoke(journal_t *, unsigned int, tid_t);
> extern void journal_clear_revoke(journal_t *);
> extern void journal_switch_revoke_table(journal_t *journal);
> +extern void journal_clear_buffer_revoked_flags(journal_t *journal);
>
> /*
> * The log thread user interface:
> --
> 1.7.5.1
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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