X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=fs%2Fxfs%2Fxfs_log.c;h=60ac5fd63f1e932b70b24e7a9bb13d3b458b0044;hb=902e7f373fff2476b53824264c12e4e76c7ec02a;hp=36fa2650b0813fdbec34da1dc87ba82a27c05547;hpb=aef4226f914016cc00affa8476ba5164dcca56fd;p=linux-2.6-microblaze.git diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 36fa2650b081..60ac5fd63f1e 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -78,13 +78,12 @@ xlog_verify_iclog( STATIC void xlog_verify_tail_lsn( struct xlog *log, - struct xlog_in_core *iclog, - xfs_lsn_t tail_lsn); + struct xlog_in_core *iclog); #else #define xlog_verify_dest_ptr(a,b) #define xlog_verify_grant_tail(a) #define xlog_verify_iclog(a,b,c) -#define xlog_verify_tail_lsn(a,b,c) +#define xlog_verify_tail_lsn(a,b) #endif STATIC int @@ -487,51 +486,80 @@ out_error: return error; } -static bool -__xlog_state_release_iclog( - struct xlog *log, - struct xlog_in_core *iclog) -{ - lockdep_assert_held(&log->l_icloglock); - - if (iclog->ic_state == XLOG_STATE_WANT_SYNC) { - /* update tail before writing to iclog */ - xfs_lsn_t tail_lsn = xlog_assign_tail_lsn(log->l_mp); - - iclog->ic_state = XLOG_STATE_SYNCING; - iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn); - xlog_verify_tail_lsn(log, iclog, tail_lsn); - /* cycle incremented when incrementing curr_block */ - trace_xlog_iclog_syncing(iclog, _RET_IP_); - return true; - } - - ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE); - return false; -} - /* * Flush iclog to disk if this is the last reference to the given iclog and the * it is in the WANT_SYNC state. + * + * If the caller passes in a non-zero @old_tail_lsn and the current log tail + * does not match, there may be metadata on disk that must be persisted before + * this iclog is written. To satisfy that requirement, set the + * XLOG_ICL_NEED_FLUSH flag as a condition for writing this iclog with the new + * log tail value. + * + * If XLOG_ICL_NEED_FUA is already set on the iclog, we need to ensure that the + * log tail is updated correctly. NEED_FUA indicates that the iclog will be + * written to stable storage, and implies that a commit record is contained + * within the iclog. We need to ensure that the log tail does not move beyond + * the tail that the first commit record in the iclog ordered against, otherwise + * correct recovery of that checkpoint becomes dependent on future operations + * performed on this iclog. + * + * Hence if NEED_FUA is set and the current iclog tail lsn is empty, write the + * current tail into iclog. Once the iclog tail is set, future operations must + * not modify it, otherwise they potentially violate ordering constraints for + * the checkpoint commit that wrote the initial tail lsn value. The tail lsn in + * the iclog will get zeroed on activation of the iclog after sync, so we + * always capture the tail lsn on the iclog on the first NEED_FUA release + * regardless of the number of active reference counts on this iclog. */ + int xlog_state_release_iclog( struct xlog *log, - struct xlog_in_core *iclog) + struct xlog_in_core *iclog, + xfs_lsn_t old_tail_lsn) { + xfs_lsn_t tail_lsn; lockdep_assert_held(&log->l_icloglock); trace_xlog_iclog_release(iclog, _RET_IP_); if (iclog->ic_state == XLOG_STATE_IOERROR) return -EIO; - if (atomic_dec_and_test(&iclog->ic_refcnt) && - __xlog_state_release_iclog(log, iclog)) { - spin_unlock(&log->l_icloglock); - xlog_sync(log, iclog); - spin_lock(&log->l_icloglock); + /* + * Grabbing the current log tail needs to be atomic w.r.t. the writing + * of the tail LSN into the iclog so we guarantee that the log tail does + * not move between deciding if a cache flush is required and writing + * the LSN into the iclog below. + */ + if (old_tail_lsn || iclog->ic_state == XLOG_STATE_WANT_SYNC) { + tail_lsn = xlog_assign_tail_lsn(log->l_mp); + + if (old_tail_lsn && tail_lsn != old_tail_lsn) + iclog->ic_flags |= XLOG_ICL_NEED_FLUSH; + + if ((iclog->ic_flags & XLOG_ICL_NEED_FUA) && + !iclog->ic_header.h_tail_lsn) + iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn); } + if (!atomic_dec_and_test(&iclog->ic_refcnt)) + return 0; + + if (iclog->ic_state != XLOG_STATE_WANT_SYNC) { + ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE); + return 0; + } + + iclog->ic_state = XLOG_STATE_SYNCING; + if (!iclog->ic_header.h_tail_lsn) + iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn); + xlog_verify_tail_lsn(log, iclog); + trace_xlog_iclog_syncing(iclog, _RET_IP_); + + spin_unlock(&log->l_icloglock); + xlog_sync(log, iclog); + spin_lock(&log->l_icloglock); return 0; } @@ -773,6 +801,21 @@ xfs_log_mount_cancel( xfs_log_unmount(mp); } +/* + * Flush out the iclog to disk ensuring that device caches are flushed and + * the iclog hits stable storage before any completion waiters are woken. + */ +static inline int +xlog_force_iclog( + struct xlog_in_core *iclog) +{ + atomic_inc(&iclog->ic_refcnt); + iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA; + if (iclog->ic_state == XLOG_STATE_ACTIVE) + xlog_state_switch_iclogs(iclog->ic_log, iclog, 0); + return xlog_state_release_iclog(iclog->ic_log, iclog, 0); +} + /* * Wait for the iclog and all prior iclogs to be written disk as required by the * log force state machine. Waiting on ic_force_wait ensures iclog completions @@ -827,13 +870,6 @@ xlog_write_unmount_record( /* account for space used by record data */ ticket->t_curr_res -= sizeof(ulf); - /* - * For external log devices, we need to flush the data device cache - * first to ensure all metadata writeback is on stable storage before we - * stamp the tail LSN into the unmount record. - */ - if (log->l_targ != log->l_mp->m_ddev_targp) - blkdev_issue_flush(log->l_targ->bt_bdev); return xlog_write(log, &vec, ticket, NULL, NULL, XLOG_UNMOUNT_TRANS); } @@ -865,18 +901,7 @@ out_err: spin_lock(&log->l_icloglock); iclog = log->l_iclog; - atomic_inc(&iclog->ic_refcnt); - if (iclog->ic_state == XLOG_STATE_ACTIVE) - xlog_state_switch_iclogs(log, iclog, 0); - else - ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC || - iclog->ic_state == XLOG_STATE_IOERROR); - /* - * Ensure the journal is fully flushed and on stable storage once the - * iclog containing the unmount record is written. - */ - iclog->ic_flags |= (XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA); - error = xlog_state_release_iclog(log, iclog); + error = xlog_force_iclog(iclog); xlog_wait_on_iclog(iclog); if (tic) { @@ -1796,10 +1821,20 @@ xlog_write_iclog( * metadata writeback and causing priority inversions. */ iclog->ic_bio.bi_opf = REQ_OP_WRITE | REQ_META | REQ_SYNC | REQ_IDLE; - if (iclog->ic_flags & XLOG_ICL_NEED_FLUSH) + if (iclog->ic_flags & XLOG_ICL_NEED_FLUSH) { iclog->ic_bio.bi_opf |= REQ_PREFLUSH; + /* + * For external log devices, we also need to flush the data + * device cache first to ensure all metadata writeback covered + * by the LSN in this iclog is on stable storage. This is slow, + * but it *must* complete before we issue the external log IO. + */ + if (log->l_targ != log->l_mp->m_ddev_targp) + blkdev_issue_flush(log->l_mp->m_ddev_targp->bt_bdev); + } if (iclog->ic_flags & XLOG_ICL_NEED_FUA) iclog->ic_bio.bi_opf |= REQ_FUA; + iclog->ic_flags &= ~(XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA); if (xlog_map_iclog_data(&iclog->ic_bio, iclog->ic_data, count)) { @@ -2310,7 +2345,7 @@ xlog_write_copy_finish( return 0; release_iclog: - error = xlog_state_release_iclog(log, iclog); + error = xlog_state_release_iclog(log, iclog, 0); spin_unlock(&log->l_icloglock); return error; } @@ -2529,7 +2564,7 @@ next_lv: ASSERT(optype & XLOG_COMMIT_TRANS); *commit_iclog = iclog; } else { - error = xlog_state_release_iclog(log, iclog); + error = xlog_state_release_iclog(log, iclog, 0); } spin_unlock(&log->l_icloglock); @@ -2567,6 +2602,7 @@ xlog_state_activate_iclog( memset(iclog->ic_header.h_cycle_data, 0, sizeof(iclog->ic_header.h_cycle_data)); iclog->ic_header.h_lsn = 0; + iclog->ic_header.h_tail_lsn = 0; } /* @@ -2967,7 +3003,7 @@ restart: * reference to the iclog. */ if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1)) - error = xlog_state_release_iclog(log, iclog); + error = xlog_state_release_iclog(log, iclog, 0); spin_unlock(&log->l_icloglock); if (error) return error; @@ -3131,6 +3167,35 @@ 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. * @@ -3165,7 +3230,6 @@ 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_); @@ -3193,39 +3257,33 @@ xfs_log_force( iclog = iclog->ic_prev; } else if (iclog->ic_state == XLOG_STATE_ACTIVE) { if (atomic_read(&iclog->ic_refcnt) == 0) { - /* - * We are the only one with access to this iclog. - * - * Flush it out now. There should be a roundoff of zero - * to show that someone has already taken care of the - * roundoff from the previous sync. - */ - atomic_inc(&iclog->ic_refcnt); - lsn = be64_to_cpu(iclog->ic_header.h_lsn); - xlog_state_switch_iclogs(log, iclog, 0); - if (xlog_state_release_iclog(log, iclog)) + /* We have exclusive access to this 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 { /* - * Someone else is writing to this iclog. - * - * Use its call to flush out the data. However, the - * other thread may not force out this LR, so we mark - * it WANT_SYNC. + * Someone else is still writing to this iclog, so we + * need to ensure that when they release the iclog it + * gets synced immediately as we may be waiting on it. */ xlog_state_switch_iclogs(log, iclog, 0); } - } else { - /* - * If the head iclog is not active nor dirty, we just attach - * ourselves to the head and go to sleep if necessary. - */ - ; } + /* + * The iclog we are about to wait on may contain the checkpoint pushed + * by the above xlog_cil_force() call, but it may not have been pushed + * to disk yet. Like the ACTIVE case above, we need to make sure caches + * are flushed when this iclog is written. + */ + if (iclog->ic_state == XLOG_STATE_WANT_SYNC) + iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA; + if (flags & XFS_LOG_SYNC) return xlog_wait_on_iclog(iclog); out_unlock: @@ -3245,6 +3303,7 @@ xlog_force_lsn( bool already_slept) { struct xlog_in_core *iclog; + bool completed; spin_lock(&log->l_icloglock); iclog = log->l_iclog; @@ -3258,7 +3317,8 @@ xlog_force_lsn( goto out_unlock; } - if (iclog->ic_state == XLOG_STATE_ACTIVE) { + switch (iclog->ic_state) { + case XLOG_STATE_ACTIVE: /* * We sleep here if we haven't already slept (e.g. this is the * first time we've looked at the correct iclog buf) and the @@ -3281,12 +3341,31 @@ xlog_force_lsn( &log->l_icloglock); return -EAGAIN; } - atomic_inc(&iclog->ic_refcnt); - xlog_state_switch_iclogs(log, iclog, 0); - if (xlog_state_release_iclog(log, 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: + /* + * This iclog may contain the checkpoint pushed by the + * xlog_cil_force_seq() call, but there are other writers still + * accessing it so it hasn't been pushed to disk yet. Like the + * ACTIVE case above, we need to make sure caches are flushed + * when this iclog is written. + */ + iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA; + break; + default: + /* + * The entire checkpoint was written by the CIL force and is on + * its way to disk already. It will be stable when it + * completes, so we don't need to manipulate caches here at all. + * We just need to wait for completion if necessary. + */ + break; } if (flags & XFS_LOG_SYNC) @@ -3559,10 +3638,10 @@ xlog_verify_grant_tail( STATIC void xlog_verify_tail_lsn( struct xlog *log, - struct xlog_in_core *iclog, - xfs_lsn_t tail_lsn) + struct xlog_in_core *iclog) { - int blocks; + xfs_lsn_t tail_lsn = be64_to_cpu(iclog->ic_header.h_tail_lsn); + int blocks; if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) { blocks =