From 7ec949212dba350f1dbc339d2db844db68b39725 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Wed, 25 Mar 2020 18:18:20 -0700
Subject: [PATCH] xfs: don't try to write a start record into every iclog
Git-commit: 7ec949212dba350f1dbc339d2db844db68b39725
Patch-mainline: v5.7-rc1
References: git-fixes
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 <dchinner@redhat.com>
[hch: pass an explicit need_start_rec argument]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Anthony Iliopoulos <ailiop@suse.com>
---
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 4a53768c5397b..33f089aa2a25b 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 64cc0bf2ab3b9..e0aeb316ce6c6 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 2b0aec37e73e4..b895e16460ee5 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
--
2.26.1