From 7ec949212dba350f1dbc339d2db844db68b39725 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Wed, 25 Mar 2020 18:18:20 -0700 Subject: [PATCH] xfs: don't try to write a start record into every iclog The xlog_write() function iterates over iclogs until it completes writing all the log vectors passed in. The ticket tracks whether a start record has been written or not, so only the first iclog gets a start record. We only ever pass single use tickets to xlog_write() so we only ever need to write a start record once per xlog_write() call. Hence we don't need to store whether we should write a start record in the ticket as the callers provide all the information we need to determine if a start record should be written. For the moment, we have to ensure that we clear the XLOG_TIC_INITED appropriately so the code in xfs_log_done() still works correctly for committing transactions. (darrick: Note the slight behavior change that we always deduct the size of the op header from the ticket, even for unmount records) Signed-off-by: Dave Chinner [hch: pass an explicit need_start_rec argument] Signed-off-by: Christoph Hellwig Reviewed-by: Brian Foster Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_log.c | 77 +++++++++++++++++++++---------------------- fs/xfs/xfs_log_cil.c | 2 +- fs/xfs/xfs_log_priv.h | 12 +++---- 3 files changed, 42 insertions(+), 49 deletions(-) diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 4a53768c5397..33f089aa2a25 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -921,7 +921,7 @@ xfs_log_write_unmount_record( /* remove inited flag, and account for space used */ tic->t_flags = 0; tic->t_curr_res -= sizeof(magic); - error = xlog_write(log, &vec, tic, &lsn, NULL, flags); + error = xlog_write(log, &vec, tic, &lsn, NULL, flags, false); /* * At this point, we're umounting anyway, so there's no point in * transitioning log state to IOERROR. Just continue... @@ -1541,7 +1541,7 @@ xlog_commit_record( ASSERT_ALWAYS(iclog); error = xlog_write(log, &vec, ticket, commitlsnp, iclog, - XLOG_COMMIT_TRANS); + XLOG_COMMIT_TRANS, false); if (error) xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR); return error; @@ -2118,23 +2118,21 @@ xlog_print_trans( } /* - * Calculate the potential space needed by the log vector. Each region gets - * its own xlog_op_header_t and may need to be double word aligned. + * Calculate the potential space needed by the log vector. We may need a start + * record, and each region gets its own struct xlog_op_header and may need to be + * double word aligned. */ static int xlog_write_calc_vec_length( struct xlog_ticket *ticket, - struct xfs_log_vec *log_vector) + struct xfs_log_vec *log_vector, + bool need_start_rec) { struct xfs_log_vec *lv; - int headers = 0; + int headers = need_start_rec ? 1 : 0; int len = 0; int i; - /* acct for start rec of xact */ - if (ticket->t_flags & XLOG_TIC_INITED) - headers++; - for (lv = log_vector; lv; lv = lv->lv_next) { /* we don't write ordered log vectors */ if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) @@ -2156,27 +2154,16 @@ xlog_write_calc_vec_length( return len; } -/* - * If first write for transaction, insert start record We can't be trying to - * commit if we are inited. We can't have any "partial_copy" if we are inited. - */ -static int +static void xlog_write_start_rec( struct xlog_op_header *ophdr, struct xlog_ticket *ticket) { - if (!(ticket->t_flags & XLOG_TIC_INITED)) - return 0; - ophdr->oh_tid = cpu_to_be32(ticket->t_tid); ophdr->oh_clientid = ticket->t_clientid; ophdr->oh_len = 0; ophdr->oh_flags = XLOG_START_TRANS; ophdr->oh_res2 = 0; - - ticket->t_flags &= ~XLOG_TIC_INITED; - - return sizeof(struct xlog_op_header); } static xlog_op_header_t * @@ -2365,7 +2352,8 @@ xlog_write( struct xlog_ticket *ticket, xfs_lsn_t *start_lsn, struct xlog_in_core **commit_iclog, - uint flags) + uint flags, + bool need_start_rec) { struct xlog_in_core *iclog = NULL; struct xfs_log_iovec *vecp; @@ -2381,23 +2369,22 @@ xlog_write( *start_lsn = 0; - len = xlog_write_calc_vec_length(ticket, log_vector); /* - * Region headers and bytes are already accounted for. - * We only need to take into account start records and - * split regions in this function. + * Region headers and bytes are already accounted for. We only need to + * take into account start records and split regions in this function. */ - if (ticket->t_flags & XLOG_TIC_INITED) - ticket->t_curr_res -= sizeof(xlog_op_header_t); + if (ticket->t_flags & XLOG_TIC_INITED) { + ticket->t_curr_res -= sizeof(struct xlog_op_header); + ticket->t_flags &= ~XLOG_TIC_INITED; + } /* - * Commit record headers need to be accounted for. These - * come in as separate writes so are easy to detect. + * Commit record headers and unmount records need to be accounted for. + * These come in as separate writes so are easy to detect. */ - if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS)) - ticket->t_curr_res -= sizeof(xlog_op_header_t); - + if (!need_start_rec) + ticket->t_curr_res -= sizeof(struct xlog_op_header); if (ticket->t_curr_res < 0) { xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES, "ctx ticket reservation ran out. Need to up reservation"); @@ -2405,6 +2392,8 @@ xlog_write( xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR); } + len = xlog_write_calc_vec_length(ticket, log_vector, need_start_rec); + index = 0; lv = log_vector; vecp = lv->lv_iovecp; @@ -2431,7 +2420,6 @@ xlog_write( while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) { struct xfs_log_iovec *reg; struct xlog_op_header *ophdr; - int start_rec_copy; int copy_len; int copy_off; bool ordered = false; @@ -2447,11 +2435,15 @@ xlog_write( ASSERT(reg->i_len % sizeof(int32_t) == 0); ASSERT((unsigned long)ptr % sizeof(int32_t) == 0); - start_rec_copy = xlog_write_start_rec(ptr, ticket); - if (start_rec_copy) { - record_cnt++; + /* + * Before we start formatting log vectors, we need to + * write a start record. Only do this for the first + * iclog we write to. + */ + if (need_start_rec) { + xlog_write_start_rec(ptr, ticket); xlog_write_adv_cnt(&ptr, &len, &log_offset, - start_rec_copy); + sizeof(struct xlog_op_header)); } ophdr = xlog_write_setup_ophdr(log, ptr, ticket, flags); @@ -2483,8 +2475,13 @@ xlog_write( xlog_write_adv_cnt(&ptr, &len, &log_offset, copy_len); } - copy_len += start_rec_copy + sizeof(xlog_op_header_t); + copy_len += sizeof(struct xlog_op_header); record_cnt++; + if (need_start_rec) { + copy_len += sizeof(struct xlog_op_header); + record_cnt++; + need_start_rec = false; + } data_cnt += contwr ? copy_len : 0; error = xlog_write_copy_finish(log, iclog, flags, diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c index 64cc0bf2ab3b..e0aeb316ce6c 100644 --- a/fs/xfs/xfs_log_cil.c +++ b/fs/xfs/xfs_log_cil.c @@ -801,7 +801,7 @@ xlog_cil_push_work( lvhdr.lv_iovecp = &lhdr; lvhdr.lv_next = ctx->lv_chain; - error = xlog_write(log, &lvhdr, tic, &ctx->start_lsn, NULL, 0); + error = xlog_write(log, &lvhdr, tic, &ctx->start_lsn, NULL, 0, true); if (error) goto out_abort_free_ticket; diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h index 2b0aec37e73e..b895e16460ee 100644 --- a/fs/xfs/xfs_log_priv.h +++ b/fs/xfs/xfs_log_priv.h @@ -439,14 +439,10 @@ xlog_write_adv_cnt(void **ptr, int *len, int *off, size_t bytes) void xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket); void xlog_print_trans(struct xfs_trans *); -int -xlog_write( - struct xlog *log, - struct xfs_log_vec *log_vector, - struct xlog_ticket *tic, - xfs_lsn_t *start_lsn, - struct xlog_in_core **commit_iclog, - uint flags); +int xlog_write(struct xlog *log, struct xfs_log_vec *log_vector, + struct xlog_ticket *tic, xfs_lsn_t *start_lsn, + struct xlog_in_core **commit_iclog, uint flags, + bool need_start_rec); /* * When we crack an atomic LSN, we sample it first so that the value will not