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xfs: don't sleep in xlog_cil_force_lsn on shutdown
Reports of a shutdown hang when fsyncing a directory have surfaced, such as this: [ 3663.394472] Call Trace: [ 3663.397199] [<ffffffff815f1889>] schedule+0x29/0x70 [ 3663.402743] [<ffffffffa01feda5>] xlog_cil_force_lsn+0x185/0x1a0 [xfs] [ 3663.416249] [<ffffffffa01fd3af>] _xfs_log_force_lsn+0x6f/0x2f0 [xfs] [ 3663.429271] [<ffffffffa01a339d>] xfs_dir_fsync+0x7d/0xe0 [xfs] [ 3663.435873] [<ffffffff811df8c5>] do_fsync+0x65/0xa0 [ 3663.441408] [<ffffffff811dfbc0>] SyS_fsync+0x10/0x20 [ 3663.447043] [<ffffffff815fc7d9>] system_call_fastpath+0x16/0x1b If we trigger a shutdown in xlog_cil_push() from xlog_write(), we will never wake waiters on the current push sequence number, so anything waiting in xlog_cil_force_lsn() for that push sequence number to come up will not get woken and hence stall the shutdown. Fix this by ensuring we call wake_up_all(&cil->xc_commit_wait) in the push abort handling, in the log shutdown code when waking all waiters, and adding a shutdown check in the sequence completion wait loops to ensure they abort when a wakeup due to a shutdown occurs. Reported-by: Boris Ranto <branto@redhat.com> Reported-by: Eric Sandeen <esandeen@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
parent
49abc3a8f8
commit
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2 changed files with 48 additions and 11 deletions
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@ -3915,11 +3915,14 @@ xfs_log_force_umount(
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retval = xlog_state_ioerror(log);
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retval = xlog_state_ioerror(log);
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spin_unlock(&log->l_icloglock);
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spin_unlock(&log->l_icloglock);
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}
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}
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/*
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/*
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* Wake up everybody waiting on xfs_log_force.
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* Wake up everybody waiting on xfs_log_force. Wake the CIL push first
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* Callback all log item committed functions as if the
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* as if the log writes were completed. The abort handling in the log
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* log writes were completed.
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* item committed callback functions will do this again under lock to
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* avoid races.
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*/
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*/
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wake_up_all(&log->l_cilp->xc_commit_wait);
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xlog_state_do_callback(log, XFS_LI_ABORTED, NULL);
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xlog_state_do_callback(log, XFS_LI_ABORTED, NULL);
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#ifdef XFSERRORDEBUG
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#ifdef XFSERRORDEBUG
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@ -385,7 +385,15 @@ xlog_cil_committed(
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xfs_extent_busy_clear(mp, &ctx->busy_extents,
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xfs_extent_busy_clear(mp, &ctx->busy_extents,
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(mp->m_flags & XFS_MOUNT_DISCARD) && !abort);
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(mp->m_flags & XFS_MOUNT_DISCARD) && !abort);
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/*
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* If we are aborting the commit, wake up anyone waiting on the
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* committing list. If we don't, then a shutdown we can leave processes
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* waiting in xlog_cil_force_lsn() waiting on a sequence commit that
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* will never happen because we aborted it.
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*/
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spin_lock(&ctx->cil->xc_push_lock);
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spin_lock(&ctx->cil->xc_push_lock);
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if (abort)
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wake_up_all(&ctx->cil->xc_commit_wait);
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list_del(&ctx->committing);
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list_del(&ctx->committing);
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spin_unlock(&ctx->cil->xc_push_lock);
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spin_unlock(&ctx->cil->xc_push_lock);
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@ -563,9 +571,19 @@ xlog_cil_push(
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restart:
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restart:
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spin_lock(&cil->xc_push_lock);
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spin_lock(&cil->xc_push_lock);
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list_for_each_entry(new_ctx, &cil->xc_committing, committing) {
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list_for_each_entry(new_ctx, &cil->xc_committing, committing) {
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/*
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* Avoid getting stuck in this loop because we were woken by the
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* shutdown, but then went back to sleep once already in the
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* shutdown state.
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*/
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if (XLOG_FORCED_SHUTDOWN(log)) {
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spin_unlock(&cil->xc_push_lock);
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goto out_abort_free_ticket;
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}
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/*
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/*
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* Higher sequences will wait for this one so skip them.
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* Higher sequences will wait for this one so skip them.
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* Don't wait for own own sequence, either.
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* Don't wait for our own sequence, either.
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*/
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*/
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if (new_ctx->sequence >= ctx->sequence)
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if (new_ctx->sequence >= ctx->sequence)
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continue;
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continue;
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@ -810,6 +828,13 @@ xlog_cil_force_lsn(
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*/
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*/
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spin_lock(&cil->xc_push_lock);
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spin_lock(&cil->xc_push_lock);
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list_for_each_entry(ctx, &cil->xc_committing, committing) {
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list_for_each_entry(ctx, &cil->xc_committing, committing) {
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/*
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* Avoid getting stuck in this loop because we were woken by the
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* shutdown, but then went back to sleep once already in the
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* shutdown state.
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*/
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if (XLOG_FORCED_SHUTDOWN(log))
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goto out_shutdown;
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if (ctx->sequence > sequence)
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if (ctx->sequence > sequence)
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continue;
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continue;
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if (!ctx->commit_lsn) {
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if (!ctx->commit_lsn) {
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@ -833,14 +858,12 @@ xlog_cil_force_lsn(
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* push sequence after the above wait loop and the CIL still contains
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* push sequence after the above wait loop and the CIL still contains
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* dirty objects.
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* dirty objects.
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*
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*
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* When the push occurs, it will empty the CIL and
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* When the push occurs, it will empty the CIL and atomically increment
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* atomically increment the currect sequence past the push sequence and
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* the currect sequence past the push sequence and move it into the
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* move it into the committing list. Of course, if the CIL is clean at
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* committing list. Of course, if the CIL is clean at the time of the
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* the time of the push, it won't have pushed the CIL at all, so in that
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* push, it won't have pushed the CIL at all, so in that case we should
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* case we should try the push for this sequence again from the start
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* try the push for this sequence again from the start just in case.
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* just in case.
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*/
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*/
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if (sequence == cil->xc_current_sequence &&
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if (sequence == cil->xc_current_sequence &&
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!list_empty(&cil->xc_cil)) {
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!list_empty(&cil->xc_cil)) {
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spin_unlock(&cil->xc_push_lock);
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spin_unlock(&cil->xc_push_lock);
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@ -849,6 +872,17 @@ xlog_cil_force_lsn(
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spin_unlock(&cil->xc_push_lock);
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spin_unlock(&cil->xc_push_lock);
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return commit_lsn;
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return commit_lsn;
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/*
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* We detected a shutdown in progress. We need to trigger the log force
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* to pass through it's iclog state machine error handling, even though
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* we are already in a shutdown state. Hence we can't return
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* NULLCOMMITLSN here as that has special meaning to log forces (i.e.
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* LSN is already stable), so we return a zero LSN instead.
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*/
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out_shutdown:
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spin_unlock(&cil->xc_push_lock);
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return 0;
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}
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}
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/*
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/*
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