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xfs: don't try to write a start record into every iclog

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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>
This commit is contained in:
Dave Chinner 2020-03-25 18:18:20 -07:00 committed by Darrick J. Wong
parent f8e566c0f5
commit 7ec949212d
3 changed files with 42 additions and 49 deletions
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77
fs/xfs/xfs_log.c
View File

@ -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,

2
fs/xfs/xfs_log_cil.c
View File

@ -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;

12
fs/xfs/xfs_log_priv.h
View File

@ -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