> When ASYNC_COMMIT is enabled, it means that the journal transaction
> coherency is handled by the commit block checksum of the transaction data
> blocks, so the commit block can be submitted to the journal at the same
> time as the transaction data blocks. The flush on the journal device
> (and the filesystem device, if they are separate) should happen after
> both are submitted.
>
> However, if ASYNC_COMMIT is NOT enabled, then the transaction data blocks
> should be submitted and flushed before the journal commit block is
> submitted, and then there should be a second cache flush afterward.
>
> ---
> > This patch is necessary before enabling flush/fua support in jbd2.
> > The flush-fua git tree has been udpated to included this between patch
> > 24 and 25.
> >
> > Thanks.
> >
> > fs/jbd2/commit.c | 29 ++++++++++++++++-------------
> > 1 files changed, 16 insertions(+), 13 deletions(-)
> >
> > diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
> > index 7c068c1..8797fd1 100644
> > --- a/fs/jbd2/commit.c
> > +++ b/fs/jbd2/commit.c
> > @@ -701,6 +701,16 @@ start_journal_io:
> > }
> > }
> >
> > + err = journal_finish_inode_data_buffers(journal, commit_transaction);
> > + if (err) {
> > + printk(KERN_WARNING
> > + "JBD2: Detected IO errors while flushing file data "
> > + "on %s\n", journal->j_devname);
> > + if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
> > + jbd2_journal_abort(journal, err);
> > + err = 0;
> > + }
> > +
> > /*
> > * If the journal is not located on the file system device,
> > * then we must flush the file system device before we issue
> > @@ -719,19 +729,6 @@ start_journal_io:
> > &cbh, crc32_sum);
> > if (err)
> > __jbd2_journal_abort_hard(journal);
> > - if (journal->j_flags & JBD2_BARRIER)
> > - blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL,
> > - BLKDEV_IFL_WAIT);
> > - }
> > -
> > - err = journal_finish_inode_data_buffers(journal, commit_transaction);
> > - if (err) {
> > - printk(KERN_WARNING
> > - "JBD2: Detected IO errors while flushing file data "
> > - "on %s\n", journal->j_devname);
> > - if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
> > - jbd2_journal_abort(journal, err);
> > - err = 0;
> > }
> >
> > /* Lo and behold: we have just managed to send a transaction to
> > @@ -845,6 +842,12 @@ wait_for_iobuf:
> > }
> > if (!err && !is_journal_aborted(journal))
> > err = journal_wait_on_commit_record(journal, cbh);
> > + if (JBD2_HAS_INCOMPAT_FEATURE(journal,
> > + JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
> > + journal->j_flags & JBD2_BARRIER) {
> > + blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL,
> > + BLKDEV_IFL_WAIT);
> > + }
> >
> > if (err)
> > jbd2_journal_abort(journal, err);
> > --
> > 1.7.1
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
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> > More majordomo info at
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>
>
> Cheers, Andreas
>
>
>
>
>
