diff options
| author | Dave Chinner <dchinner@redhat.com> | 2021-07-27 16:23:49 -0700 |
|---|---|---|
| committer | Darrick J. Wong <djwong@kernel.org> | 2021-07-29 09:27:28 -0700 |
| commit | 8191d8222c514c69a8e1ac46bd9812b9e0aab7d0 (patch) | |
| tree | 3c973fc94ee8d22389bc5fa3a96b755934d45fc0 /fs/xfs/xfs_log.c | |
| parent | 2bf1ec0ff067ff8f692d261b29c713f3583f7e2a (diff) | |
xfs: avoid unnecessary waits in xfs_log_force_lsn()
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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Diffstat (limited to 'fs/xfs/xfs_log.c')
| -rw-r--r-- | fs/xfs/xfs_log.c | 42 |
1 files changed, 37 insertions, 5 deletions
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 160b8bb7ee60..1c328efdca66 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -3144,6 +3144,35 @@ xlog_state_switch_iclogs( } /* + * 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. * * Data may be written to the in-core log during this call. However, @@ -3177,7 +3206,6 @@ 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_); @@ -3206,11 +3234,12 @@ 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 (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) + if (completed) goto out_unlock; } else { /* @@ -3250,6 +3279,7 @@ xlog_force_lsn( bool already_slept) { struct xlog_in_core *iclog; + bool completed; spin_lock(&log->l_icloglock); iclog = log->l_iclog; @@ -3287,10 +3317,12 @@ 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: /* |