| Message ID | 20210722015335.3063274-6-david@fromorbit.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xfs: fix log cache flush regressions | expand |
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
On Thu, Jul 22, 2021 at 11:53:35AM +1000, Dave Chinner wrote: > From: Dave Chinner <dchinner@redhat.com> > > Before waiting on a iclog in xfs_log_force_lsn(), we don't check to > see if the iclog has already been completed and the contents on > stable storage. We check for completed iclogs in xfs_log_force(), so > we should do the same thing for xfs_log_force_lsn(). > > This fixed some random up-to-30s pauses seen in unmounting > filesystems in some tests. A log force ends up waiting on completed > iclog, and that doesn't then get flushed (and hence the log force > get completed) until the background log worker issues a log force > that flushes the iclog in question. Then the unmount unblocks and > continues. > > Signed-off-by: Dave Chinner <dchinner@redhat.com> Heh. Reviewed-by: Darrick J. Wong <djwong@kernel.org> --D > --- > fs/xfs/xfs_log.c | 47 +++++++++++++++++++++++++++++++++++++---------- > 1 file changed, 37 insertions(+), 10 deletions(-) > > diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c > index 7da42c0656e3..baee9871cd65 100644 > --- a/fs/xfs/xfs_log.c > +++ b/fs/xfs/xfs_log.c > @@ -3147,6 +3147,35 @@ xlog_state_switch_iclogs( > log->l_iclog = iclog->ic_next; > } > > +/* > + * Force the iclog to disk and check if the iclog has been completed before > + * xlog_force_iclog() returns. This can happen on synchronous (e.g. > + * pmem) or fast async storage because we drop the icloglock to issue the IO. > + * If completion has already occurred, tell the caller so that it can avoid an > + * unnecessary wait on the iclog. > + */ > +static int > +xlog_force_and_check_iclog( > + struct xlog_in_core *iclog, > + bool *completed) > +{ > + xfs_lsn_t lsn = be64_to_cpu(iclog->ic_header.h_lsn); > + int error; > + > + *completed = false; > + error = xlog_force_iclog(iclog); > + if (error) > + return error; > + > + /* > + * If the iclog has already been completed and reused the header LSN > + * will have been rewritten by completion > + */ > + if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) > + *completed = true; > + return 0; > +} > + > /* > * Write out all data in the in-core log as of this exact moment in time. > * > @@ -3181,7 +3210,6 @@ xfs_log_force( > { > struct xlog *log = mp->m_log; > struct xlog_in_core *iclog; > - xfs_lsn_t lsn; > > XFS_STATS_INC(mp, xs_log_force); > trace_xfs_log_force(mp, 0, _RET_IP_); > @@ -3210,15 +3238,11 @@ xfs_log_force( > } else if (iclog->ic_state == XLOG_STATE_ACTIVE) { > if (atomic_read(&iclog->ic_refcnt) == 0) { > /* We have exclusive access to this iclog. */ > - lsn = be64_to_cpu(iclog->ic_header.h_lsn); > - if (xlog_force_iclog(iclog)) > + bool completed; > + > + if (xlog_force_and_check_iclog(iclog, &completed)) > goto out_error; > - /* > - * If the iclog has already been completed and reused > - * the header LSN will have been rewritten. Don't wait > - * on these iclogs that contain future modifications. > - */ > - if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) > + if (completed) > goto out_unlock; > } else { > /* > @@ -3258,6 +3282,7 @@ xlog_force_lsn( > bool already_slept) > { > struct xlog_in_core *iclog; > + bool completed; > > spin_lock(&log->l_icloglock); > iclog = log->l_iclog; > @@ -3295,10 +3320,12 @@ xlog_force_lsn( > &log->l_icloglock); > return -EAGAIN; > } > - if (xlog_force_iclog(iclog)) > + if (xlog_force_and_check_iclog(iclog, &completed)) > goto out_error; > if (log_flushed) > *log_flushed = 1; > + if (completed) > + goto out_unlock; > break; > case XLOG_STATE_WANT_SYNC: > /* > -- > 2.31.1 >
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 7da42c0656e3..baee9871cd65 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -3147,6 +3147,35 @@ xlog_state_switch_iclogs( log->l_iclog = iclog->ic_next; } +/* + * Force the iclog to disk and check if the iclog has been completed before + * xlog_force_iclog() returns. This can happen on synchronous (e.g. + * pmem) or fast async storage because we drop the icloglock to issue the IO. + * If completion has already occurred, tell the caller so that it can avoid an + * unnecessary wait on the iclog. + */ +static int +xlog_force_and_check_iclog( + struct xlog_in_core *iclog, + bool *completed) +{ + xfs_lsn_t lsn = be64_to_cpu(iclog->ic_header.h_lsn); + int error; + + *completed = false; + error = xlog_force_iclog(iclog); + if (error) + return error; + + /* + * If the iclog has already been completed and reused the header LSN + * will have been rewritten by completion + */ + if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) + *completed = true; + return 0; +} + /* * Write out all data in the in-core log as of this exact moment in time. * @@ -3181,7 +3210,6 @@ xfs_log_force( { struct xlog *log = mp->m_log; struct xlog_in_core *iclog; - xfs_lsn_t lsn; XFS_STATS_INC(mp, xs_log_force); trace_xfs_log_force(mp, 0, _RET_IP_); @@ -3210,15 +3238,11 @@ xfs_log_force( } else if (iclog->ic_state == XLOG_STATE_ACTIVE) { if (atomic_read(&iclog->ic_refcnt) == 0) { /* We have exclusive access to this iclog. */ - lsn = be64_to_cpu(iclog->ic_header.h_lsn); - if (xlog_force_iclog(iclog)) + bool completed; + + if (xlog_force_and_check_iclog(iclog, &completed)) goto out_error; - /* - * If the iclog has already been completed and reused - * the header LSN will have been rewritten. Don't wait - * on these iclogs that contain future modifications. - */ - if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) + if (completed) goto out_unlock; } else { /* @@ -3258,6 +3282,7 @@ xlog_force_lsn( bool already_slept) { struct xlog_in_core *iclog; + bool completed; spin_lock(&log->l_icloglock); iclog = log->l_iclog; @@ -3295,10 +3320,12 @@ xlog_force_lsn( &log->l_icloglock); return -EAGAIN; } - if (xlog_force_iclog(iclog)) + if (xlog_force_and_check_iclog(iclog, &completed)) goto out_error; if (log_flushed) *log_flushed = 1; + if (completed) + goto out_unlock; break; case XLOG_STATE_WANT_SYNC: /*