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xfs: attach iclog callbacks in xlog_cil_set_ctx_write_state() 

Now that we have a mechanism to guarantee that the callbacks
attached to an iclog are owned by the context that attaches them
until they drop their reference to the iclog via
xlog_state_release_iclog(), we can attach callbacks to the iclog at
any time we have an active reference to the iclog.

xlog_state_get_iclog_space() always guarantees that the commit
record will fit in the iclog it returns, so we can move this IO
callback setting to xlog_cil_set_ctx_write_state(), record the
commit iclog in the context and remove the need for the commit iclog
to be returned by xlog_write() altogether.

This, in turn, allows us to move the wakeup for ordered commit
record writes up into xlog_cil_set_ctx_write_state(), too, because
we have been guaranteed that this commit record will be physically
located in the iclog before any waiting commit record at a higher
sequence number will be granted iclog space.

This further cleans up the post commit record write processing in
the CIL push code, especially as xlog_state_release_iclog() will now
clean up the context when shutdown errors occur.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
This commit is contained in:
Dave Chinner 2021-08-10 18:00:43 -07:00 committed by Darrick J. Wong
parent bf034bc827
commit caa80090d1
3 changed files with 70 additions and 74 deletions
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47
fs/xfs/xfs_log.c
View File

@ -933,7 +933,7 @@ xlog_write_unmount_record(
/* account for space used by record data */
ticket->t_curr_res -= sizeof(ulf);
return xlog_write(log, NULL, &vec, ticket, NULL, XLOG_UNMOUNT_TRANS);
return xlog_write(log, NULL, &vec, ticket, XLOG_UNMOUNT_TRANS);
}
/*
@ -2380,8 +2380,7 @@ xlog_write_copy_finish(
int *data_cnt,
int *partial_copy,
int *partial_copy_len,
int log_offset,
struct xlog_in_core **commit_iclog)
int log_offset)
{
int error;
@ -2400,27 +2399,20 @@ xlog_write_copy_finish(
*partial_copy = 0;
*partial_copy_len = 0;
if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
/* no more space in this iclog - push it. */
spin_lock(&log->l_icloglock);
xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
*record_cnt = 0;
*data_cnt = 0;
if (iclog->ic_size - log_offset > sizeof(xlog_op_header_t))
return 0;
if (iclog->ic_state == XLOG_STATE_ACTIVE)
xlog_state_switch_iclogs(log, iclog, 0);
else
ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC ||
xlog_is_shutdown(log));
if (!commit_iclog)
goto release_iclog;
spin_unlock(&log->l_icloglock);
ASSERT(flags & XLOG_COMMIT_TRANS);
*commit_iclog = iclog;
}
return 0;
/* no more space in this iclog - push it. */
spin_lock(&log->l_icloglock);
xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
*record_cnt = 0;
*data_cnt = 0;
if (iclog->ic_state == XLOG_STATE_ACTIVE)
xlog_state_switch_iclogs(log, iclog, 0);
else
ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC ||
xlog_is_shutdown(log));
release_iclog:
error = xlog_state_release_iclog(log, iclog, 0);
spin_unlock(&log->l_icloglock);
@ -2473,7 +2465,6 @@ xlog_write(
struct xfs_cil_ctx *ctx,
struct xfs_log_vec *log_vector,
struct xlog_ticket *ticket,
struct xlog_in_core **commit_iclog,
uint optype)
{
struct xlog_in_core *iclog = NULL;
@ -2602,8 +2593,7 @@ xlog_write(
&record_cnt, &data_cnt,
&partial_copy,
&partial_copy_len,
log_offset,
commit_iclog);
log_offset);
if (error)
return error;
@ -2641,12 +2631,7 @@ xlog_write(
spin_lock(&log->l_icloglock);
xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
if (commit_iclog) {
ASSERT(optype & XLOG_COMMIT_TRANS);
*commit_iclog = iclog;
} else {
error = xlog_state_release_iclog(log, iclog, 0);
}
error = xlog_state_release_iclog(log, iclog, 0);
spin_unlock(&log->l_icloglock);
return error;

94
fs/xfs/xfs_log_cil.c
View File

@ -646,11 +646,41 @@ xlog_cil_set_ctx_write_state(
xfs_lsn_t lsn = be64_to_cpu(iclog->ic_header.h_lsn);
ASSERT(!ctx->commit_lsn);
spin_lock(&cil->xc_push_lock);
if (!ctx->start_lsn)
if (!ctx->start_lsn) {
spin_lock(&cil->xc_push_lock);
ctx->start_lsn = lsn;
else
ctx->commit_lsn = lsn;
spin_unlock(&cil->xc_push_lock);
return;
}
/*
* Take a reference to the iclog for the context so that we still hold
* it when xlog_write is done and has released it. This means the
* context controls when the iclog is released for IO.
*/
atomic_inc(&iclog->ic_refcnt);
/*
* xlog_state_get_iclog_space() guarantees there is enough space in the
* iclog for an entire commit record, so we can attach the context
* callbacks now. This needs to be done before we make the commit_lsn
* visible to waiters so that checkpoints with commit records in the
* same iclog order their IO completion callbacks in the same order that
* the commit records appear in the iclog.
*/
spin_lock(&cil->xc_log->l_icloglock);
list_add_tail(&ctx->iclog_entry, &iclog->ic_callbacks);
spin_unlock(&cil->xc_log->l_icloglock);
/*
* Now we can record the commit LSN and wake anyone waiting for this
* sequence to have the ordered commit record assigned to a physical
* location in the log.
*/
spin_lock(&cil->xc_push_lock);
ctx->commit_iclog = iclog;
ctx->commit_lsn = lsn;
wake_up_all(&cil->xc_commit_wait);
spin_unlock(&cil->xc_push_lock);
}
@ -707,8 +737,7 @@ xlog_cil_order_write(
*/
static int
xlog_cil_write_commit_record(
struct xfs_cil_ctx *ctx,
struct xlog_in_core **iclog)
struct xfs_cil_ctx *ctx)
{
struct xlog *log = ctx->cil->xc_log;
struct xfs_log_iovec reg = {
@ -725,8 +754,7 @@ xlog_cil_write_commit_record(
if (xlog_is_shutdown(log))
return -EIO;
error = xlog_write(log, ctx, &vec, ctx->ticket, iclog,
XLOG_COMMIT_TRANS);
error = xlog_write(log, ctx, &vec, ctx->ticket, XLOG_COMMIT_TRANS);
if (error)
xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
return error;
@ -756,7 +784,6 @@ xlog_cil_push_work(
struct xfs_log_vec *lv;
struct xfs_cil_ctx *ctx;
struct xfs_cil_ctx *new_ctx;
struct xlog_in_core *commit_iclog;
struct xlog_ticket *tic;
int num_iovecs;
int error = 0;
@ -945,7 +972,7 @@ xlog_cil_push_work(
*/
wait_for_completion(&bdev_flush);
error = xlog_write(log, ctx, &lvhdr, tic, NULL, XLOG_START_TRANS);
error = xlog_write(log, ctx, &lvhdr, tic, XLOG_START_TRANS);
if (error)
goto out_abort_free_ticket;
@ -953,36 +980,12 @@ xlog_cil_push_work(
if (error)
goto out_abort_free_ticket;
error = xlog_cil_write_commit_record(ctx, &commit_iclog);
error = xlog_cil_write_commit_record(ctx);
if (error)
goto out_abort_free_ticket;
xfs_log_ticket_ungrant(log, tic);
/*
* Once we attach the ctx to the iclog, it is effectively owned by the
* iclog and we can only use it while we still have an active reference
* to the iclog. i.e. once we call xlog_state_release_iclog() we can no
* longer safely reference the ctx.
*/
spin_lock(&log->l_icloglock);
if (xlog_is_shutdown(log)) {
spin_unlock(&log->l_icloglock);
goto out_abort;
}
ASSERT_ALWAYS(commit_iclog->ic_state == XLOG_STATE_ACTIVE ||
commit_iclog->ic_state == XLOG_STATE_WANT_SYNC);
list_add_tail(&ctx->iclog_entry, &commit_iclog->ic_callbacks);
/*
* now the checkpoint commit is complete and we've attached the
* callbacks to the iclog we can assign the commit LSN to the context
* and wake up anyone who is waiting for the commit to complete.
*/
spin_lock(&cil->xc_push_lock);
wake_up_all(&cil->xc_commit_wait);
spin_unlock(&cil->xc_push_lock);
/*
* If the checkpoint spans multiple iclogs, wait for all previous iclogs
* to complete before we submit the commit_iclog. We can't use state
@ -995,17 +998,18 @@ xlog_cil_push_work(
* iclog header lsn and compare it to the commit lsn to determine if we
* need to wait on iclogs or not.
*/
spin_lock(&log->l_icloglock);
if (ctx->start_lsn != ctx->commit_lsn) {
xfs_lsn_t plsn;
plsn = be64_to_cpu(commit_iclog->ic_prev->ic_header.h_lsn);
plsn = be64_to_cpu(ctx->commit_iclog->ic_prev->ic_header.h_lsn);
if (plsn && XFS_LSN_CMP(plsn, ctx->commit_lsn) < 0) {
/*
* Waiting on ic_force_wait orders the completion of
* iclogs older than ic_prev. Hence we only need to wait
* on the most recent older iclog here.
*/
xlog_wait_on_iclog(commit_iclog->ic_prev);
xlog_wait_on_iclog(ctx->commit_iclog->ic_prev);
spin_lock(&log->l_icloglock);
}
@ -1013,7 +1017,7 @@ xlog_cil_push_work(
* We need to issue a pre-flush so that the ordering for this
* checkpoint is correctly preserved down to stable storage.
*/
commit_iclog->ic_flags |= XLOG_ICL_NEED_FLUSH;
ctx->commit_iclog->ic_flags |= XLOG_ICL_NEED_FLUSH;
}
/*
@ -1021,8 +1025,8 @@ xlog_cil_push_work(
* journal IO vs metadata writeback IO is correctly ordered on stable
* storage.
*/
commit_iclog->ic_flags |= XLOG_ICL_NEED_FUA;
xlog_state_release_iclog(log, commit_iclog, preflush_tail_lsn);
ctx->commit_iclog->ic_flags |= XLOG_ICL_NEED_FUA;
xlog_state_release_iclog(log, ctx->commit_iclog, preflush_tail_lsn);
/* Not safe to reference ctx now! */
@ -1037,9 +1041,15 @@ xlog_cil_push_work(
out_abort_free_ticket:
xfs_log_ticket_ungrant(log, tic);
out_abort:
ASSERT(xlog_is_shutdown(log));
xlog_cil_committed(ctx);
if (!ctx->commit_iclog) {
xlog_cil_committed(ctx);
return;
}
spin_lock(&log->l_icloglock);
xlog_state_release_iclog(log, ctx->commit_iclog, 0);
/* Not safe to reference ctx now! */
spin_unlock(&log->l_icloglock);
}
/*

3
fs/xfs/xfs_log_priv.h
View File

@ -240,6 +240,7 @@ struct xfs_cil_ctx {
xfs_csn_t sequence; /* chkpt sequence # */
xfs_lsn_t start_lsn; /* first LSN of chkpt commit */
xfs_lsn_t commit_lsn; /* chkpt commit record lsn */
struct xlog_in_core *commit_iclog;
struct xlog_ticket *ticket; /* chkpt ticket */
int nvecs; /* number of regions */
int space_used; /* aggregate size of regions */
@ -514,7 +515,7 @@ 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_cil_ctx *ctx,
struct xfs_log_vec *log_vector, struct xlog_ticket *tic,
struct xlog_in_core **commit_iclog, uint optype);
uint optype);
void xfs_log_ticket_ungrant(struct xlog *log, struct xlog_ticket *ticket);
void xfs_log_ticket_regrant(struct xlog *log, struct xlog_ticket *ticket);