Re: [RFC v5 PATCH 3/9] xfs: automatic relogging reservation management

Dave Chinner
2020-03-03T04:07:43Z

On Tue, Mar 03, 2020 at 10:25:29AM +1100, Dave Chinner wrote:
> On Mon, Mar 02, 2020 at 01:06:50PM -0500, Brian Foster wrote:
> OK, XLOG_TIC_INITED is redundant, and should be removed. And
> xfs_log_done() needs to be split into two, one for releasing the
> ticket, one for completing the xlog_write() call. Compile tested
> only patch below for you :P

And now with sample patch.

-Dave.
--
Dave Chinner
david@fromorbit.com

xfs: kill XLOG_TIC_INITED

From: Dave Chinner <dchinner@redhat.com>

Delayed logging made this redundant as we never directly write
transactions to the log anymore. Hence we no longer make multiple
xlog_write() calls for a transaction as we format individual items
in a transaction, and hence don't need to keep track of whether we
should be writing a start record for every xlog_write call.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_log.c | 79 ++++++++++++++++++---------------------------------
fs/xfs/xfs_log.h | 4 ---
fs/xfs/xfs_log_cil.c | 13 +++++----
fs/xfs/xfs_log_priv.h | 18 ++++++------
fs/xfs/xfs_trans.c | 24 ++++++++--------
5 files changed, 55 insertions(+), 83 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index f6006d94a581..a45f3eefee39 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -496,8 +496,8 @@ xfs_log_reserve(
* This routine is called when a user of a log manager ticket is done with
* the reservation. If the ticket was ever used, then a commit record for
* the associated transaction is written out as a log operation header with
- * no data. The flag XLOG_TIC_INITED is set when the first write occurs with
- * a given ticket. If the ticket was one with a permanent reservation, then
+ * no data.
+ * If the ticket was one with a permanent reservation, then
* a few operations are done differently. Permanent reservation tickets by
* default don't release the reservation. They just commit the current
* transaction with the belief that the reservation is still needed. A flag
@@ -506,49 +506,38 @@ xfs_log_reserve(
* the inited state again. By doing this, a start record will be written
* out when the next write occurs.
*/
-xfs_lsn_t
-xfs_log_done(
- struct xfs_mount *mp,
+int
+xlog_write_done(
+ struct xlog *log,
struct xlog_ticket *ticket,
struct xlog_in_core **iclog,
- bool regrant)
+ xfs_lsn_t *lsn)
{
- struct xlog *log = mp->m_log;
- xfs_lsn_t lsn = 0;
-
- if (XLOG_FORCED_SHUTDOWN(log) ||
- /*
- * If nothing was ever written, don't write out commit record.
- * If we get an error, just continue and give back the log ticket.
- */
- (((ticket->t_flags & XLOG_TIC_INITED) == 0) &&
- (xlog_commit_record(log, ticket, iclog, &lsn)))) {
- lsn = (xfs_lsn_t) -1;
- regrant = false;
- }
+ if (XLOG_FORCED_SHUTDOWN(log))
+ return -EIO;

+ return xlog_commit_record(log, ticket, iclog, lsn);
+}

+/*
+ * Release or regrant the ticket reservation now the transaction is done with
+ * it depending on caller context. Rolling transactions need the ticket
+ * regranted, otherwise we release it completely.
+ */
+void
+xlog_ticket_done(
+ struct xlog *log,
+ struct xlog_ticket *ticket,
+ bool regrant)
+{
if (!regrant) {
trace_xfs_log_done_nonperm(log, ticket);
-
- /*
- * Release ticket if not permanent reservation or a specific
- * request has been made to release a permanent reservation.
- */
xlog_ungrant_log_space(log, ticket);
} else {
trace_xfs_log_done_perm(log, ticket);
-
xlog_regrant_reserve_log_space(log, ticket);
- /* If this ticket was a permanent reservation and we aren't
- * trying to release it, reset the inited flags; so next time
- * we write, a start record will be written out.
- */
- ticket->t_flags |= XLOG_TIC_INITED;
}
-
xfs_log_ticket_put(ticket);
- return lsn;
}

static bool
@@ -2148,8 +2137,9 @@ 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 always write a
+ * start record, and each region gets its own xlog_op_header_t and may need to
+ * be double word aligned.
*/
static int
xlog_write_calc_vec_length(
@@ -2157,14 +2147,10 @@ xlog_write_calc_vec_length(
struct xfs_log_vec *log_vector)
{
struct xfs_log_vec *lv;
- int headers = 0;
+ int headers = 1;
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)
@@ -2195,17 +2181,11 @@ 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);
}

@@ -2410,12 +2390,10 @@ xlog_write(
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);
+ ticket->t_curr_res -= sizeof(xlog_op_header_t);

/*
* Commit record headers need to be accounted for. These
@@ -3609,7 +3587,6 @@ xlog_ticket_alloc(
tic->t_ocnt = cnt;
tic->t_tid = prandom_u32();
tic->t_clientid = client;
- tic->t_flags = XLOG_TIC_INITED;
if (permanent)
tic->t_flags |= XLOG_TIC_PERM_RESERV;

diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h
index 84e06805160f..85f8d0966811 100644
--- a/fs/xfs/xfs_log.h
+++ b/fs/xfs/xfs_log.h
@@ -105,10 +105,6 @@ struct xfs_log_item;
struct xfs_item_ops;
struct xfs_trans;

-xfs_lsn_t xfs_log_done(struct xfs_mount *mp,
- struct xlog_ticket *ticket,
- struct xlog_in_core **iclog,
- bool regrant);
int xfs_log_force(struct xfs_mount *mp, uint flags);
int xfs_log_force_lsn(struct xfs_mount *mp, xfs_lsn_t lsn, uint flags,
int *log_forced);
diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index 48435cf2aa16..255065d276fc 100644
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -841,10 +841,11 @@ xlog_cil_push(
}
spin_unlock(&cil->xc_push_lock);

- /* xfs_log_done always frees the ticket on error. */
- commit_lsn = xfs_log_done(log->l_mp, tic, &commit_iclog, false);
- if (commit_lsn == -1)
- goto out_abort;
+ error = xlog_write_done(log, tic, &commit_iclog, &commit_lsn);
+ if (error)
+ goto out_abort_free_ticket;
+
+ xlog_ticket_done(log, tic, false);

spin_lock(&commit_iclog->ic_callback_lock);
if (commit_iclog->ic_state == XLOG_STATE_IOERROR) {
@@ -876,7 +877,7 @@ xlog_cil_push(
return 0;

out_abort_free_ticket:
- xfs_log_ticket_put(tic);
+ xlog_ticket_done(log, tic, false);
out_abort:
xlog_cil_committed(ctx, true);
return -EIO;
@@ -1017,7 +1018,7 @@ xfs_log_commit_cil(
if (commit_lsn)
*commit_lsn = xc_commit_lsn;

- xfs_log_done(mp, tp->t_ticket, NULL, regrant);
+ xlog_ticket_done(log, tp->t_ticket, regrant);
tp->t_ticket = NULL;
xfs_trans_unreserve_and_mod_sb(tp);

diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index b192c5a9f9fd..6965d164ff45 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -53,11 +53,9 @@ enum xlog_iclog_state {
/*
* Flags to log ticket
*/
-#define XLOG_TIC_INITED 0x1 /* has been initialized */
#define XLOG_TIC_PERM_RESERV 0x2 /* permanent reservation */

#define XLOG_TIC_FLAGS \
- { XLOG_TIC_INITED, "XLOG_TIC_INITED" }, \
{ XLOG_TIC_PERM_RESERV, "XLOG_TIC_PERM_RESERV" }

/*
@@ -438,14 +436,14 @@ 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);
+int xlog_write_done(struct xlog *log, struct xlog_ticket *ticket,
+ struct xlog_in_core **iclog, xfs_lsn_t *lsn);
+void xlog_ticket_done(struct xlog *log, struct xlog_ticket *ticket,
+ bool regrant);

/*
* When we crack an atomic LSN, we sample it first so that the value will not
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 3b208f9a865c..85ea3727878b 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -9,6 +9,7 @@
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
+#include "xfs_log_priv.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_extent_busy.h"
@@ -150,8 +151,9 @@ xfs_trans_reserve(
uint blocks,
uint rtextents)
{
- int error = 0;
- bool rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;
+ struct xfs_mount *mp = tp->t_mountp;
+ int error = 0;
+ bool rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;

/* Mark this thread as being in a transaction */
current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
@@ -162,7 +164,7 @@ xfs_trans_reserve(
* fail if the count would go below zero.
*/
if (blocks > 0) {
- error = xfs_mod_fdblocks(tp->t_mountp, -((int64_t)blocks), rsvd);
+ error = xfs_mod_fdblocks(mp, -((int64_t)blocks), rsvd);
if (error != 0) {
current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
return -ENOSPC;
@@ -191,9 +193,9 @@ xfs_trans_reserve(

if (tp->t_ticket != NULL) {
ASSERT(resp->tr_logflags & XFS_TRANS_PERM_LOG_RES);
- error = xfs_log_regrant(tp->t_mountp, tp->t_ticket);
+ error = xfs_log_regrant(mp, tp->t_ticket);
} else {
- error = xfs_log_reserve(tp->t_mountp,
+ error = xfs_log_reserve(mp,
resp->tr_logres,
resp->tr_logcount,
&tp->t_ticket, XFS_TRANSACTION,
@@ -213,7 +215,7 @@ xfs_trans_reserve(
* fail if the count would go below zero.
*/
if (rtextents > 0) {
- error = xfs_mod_frextents(tp->t_mountp, -((int64_t)rtextents));
+ error = xfs_mod_frextents(mp, -((int64_t)rtextents));
if (error) {
error = -ENOSPC;
goto undo_log;
@@ -229,7 +231,7 @@ xfs_trans_reserve(
*/
undo_log:
if (resp->tr_logres > 0) {
- xfs_log_done(tp->t_mountp, tp->t_ticket, NULL, false);
+ xlog_ticket_done(mp->m_log, tp->t_ticket, false);
tp->t_ticket = NULL;
tp->t_log_res = 0;
tp->t_flags &= ~XFS_TRANS_PERM_LOG_RES;
@@ -237,7 +239,7 @@ xfs_trans_reserve(

undo_blocks:
if (blocks > 0) {
- xfs_mod_fdblocks(tp->t_mountp, (int64_t)blocks, rsvd);
+ xfs_mod_fdblocks(mp, (int64_t)blocks, rsvd);
tp->t_blk_res = 0;
}

@@ -999,9 +1001,7 @@ __xfs_trans_commit(
*/
xfs_trans_unreserve_and_mod_dquots(tp);
if (tp->t_ticket) {
- commit_lsn = xfs_log_done(mp, tp->t_ticket, NULL, regrant);
- if (commit_lsn == -1 && !error)
- error = -EIO;
+ xlog_ticket_done(mp->m_log, tp->t_ticket, regrant);
tp->t_ticket = NULL;
}
current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
@@ -1060,7 +1060,7 @@ xfs_trans_cancel(
xfs_trans_unreserve_and_mod_dquots(tp);

if (tp->t_ticket) {
- xfs_log_done(mp, tp->t_ticket, NULL, false);
+ xlog_ticket_done(mp->m_log, tp->t_ticket, false);
tp->t_ticket = NULL;
}