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428c4435b0
Because we are going to use the same list-based discard submission interface for fstrim-based discards, too. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
1811 lines
56 KiB
C
1811 lines
56 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2010 Red Hat, Inc. All Rights Reserved.
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*/
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#include "xfs.h"
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#include "xfs_fs.h"
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#include "xfs_format.h"
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#include "xfs_log_format.h"
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#include "xfs_shared.h"
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#include "xfs_trans_resv.h"
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#include "xfs_mount.h"
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#include "xfs_extent_busy.h"
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#include "xfs_trans.h"
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#include "xfs_trans_priv.h"
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#include "xfs_log.h"
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#include "xfs_log_priv.h"
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#include "xfs_trace.h"
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#include "xfs_discard.h"
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/*
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* Allocate a new ticket. Failing to get a new ticket makes it really hard to
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* recover, so we don't allow failure here. Also, we allocate in a context that
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* we don't want to be issuing transactions from, so we need to tell the
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* allocation code this as well.
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*
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* We don't reserve any space for the ticket - we are going to steal whatever
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* space we require from transactions as they commit. To ensure we reserve all
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* the space required, we need to set the current reservation of the ticket to
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* zero so that we know to steal the initial transaction overhead from the
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* first transaction commit.
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*/
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static struct xlog_ticket *
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xlog_cil_ticket_alloc(
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struct xlog *log)
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{
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struct xlog_ticket *tic;
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tic = xlog_ticket_alloc(log, 0, 1, 0);
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/*
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* set the current reservation to zero so we know to steal the basic
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* transaction overhead reservation from the first transaction commit.
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*/
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tic->t_curr_res = 0;
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tic->t_iclog_hdrs = 0;
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return tic;
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}
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static inline void
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xlog_cil_set_iclog_hdr_count(struct xfs_cil *cil)
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{
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struct xlog *log = cil->xc_log;
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atomic_set(&cil->xc_iclog_hdrs,
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(XLOG_CIL_BLOCKING_SPACE_LIMIT(log) /
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(log->l_iclog_size - log->l_iclog_hsize)));
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}
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/*
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* Check if the current log item was first committed in this sequence.
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* We can't rely on just the log item being in the CIL, we have to check
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* the recorded commit sequence number.
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*
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* Note: for this to be used in a non-racy manner, it has to be called with
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* CIL flushing locked out. As a result, it should only be used during the
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* transaction commit process when deciding what to format into the item.
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*/
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static bool
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xlog_item_in_current_chkpt(
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struct xfs_cil *cil,
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struct xfs_log_item *lip)
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{
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if (test_bit(XLOG_CIL_EMPTY, &cil->xc_flags))
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return false;
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/*
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* li_seq is written on the first commit of a log item to record the
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* first checkpoint it is written to. Hence if it is different to the
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* current sequence, we're in a new checkpoint.
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*/
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return lip->li_seq == READ_ONCE(cil->xc_current_sequence);
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}
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bool
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xfs_log_item_in_current_chkpt(
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struct xfs_log_item *lip)
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{
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return xlog_item_in_current_chkpt(lip->li_log->l_cilp, lip);
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}
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/*
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* Unavoidable forward declaration - xlog_cil_push_work() calls
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* xlog_cil_ctx_alloc() itself.
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*/
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static void xlog_cil_push_work(struct work_struct *work);
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static struct xfs_cil_ctx *
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xlog_cil_ctx_alloc(void)
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{
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struct xfs_cil_ctx *ctx;
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ctx = kmem_zalloc(sizeof(*ctx), KM_NOFS);
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INIT_LIST_HEAD(&ctx->committing);
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INIT_LIST_HEAD(&ctx->busy_extents.extent_list);
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INIT_LIST_HEAD(&ctx->log_items);
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INIT_LIST_HEAD(&ctx->lv_chain);
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INIT_WORK(&ctx->push_work, xlog_cil_push_work);
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return ctx;
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}
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/*
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* Aggregate the CIL per cpu structures into global counts, lists, etc and
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* clear the percpu state ready for the next context to use. This is called
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* from the push code with the context lock held exclusively, hence nothing else
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* will be accessing or modifying the per-cpu counters.
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*/
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static void
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xlog_cil_push_pcp_aggregate(
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struct xfs_cil *cil,
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struct xfs_cil_ctx *ctx)
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{
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struct xlog_cil_pcp *cilpcp;
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int cpu;
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for_each_cpu(cpu, &ctx->cil_pcpmask) {
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cilpcp = per_cpu_ptr(cil->xc_pcp, cpu);
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ctx->ticket->t_curr_res += cilpcp->space_reserved;
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cilpcp->space_reserved = 0;
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if (!list_empty(&cilpcp->busy_extents)) {
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list_splice_init(&cilpcp->busy_extents,
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&ctx->busy_extents.extent_list);
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}
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if (!list_empty(&cilpcp->log_items))
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list_splice_init(&cilpcp->log_items, &ctx->log_items);
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/*
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* We're in the middle of switching cil contexts. Reset the
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* counter we use to detect when the current context is nearing
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* full.
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*/
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cilpcp->space_used = 0;
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}
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}
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/*
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* Aggregate the CIL per-cpu space used counters into the global atomic value.
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* This is called when the per-cpu counter aggregation will first pass the soft
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* limit threshold so we can switch to atomic counter aggregation for accurate
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* detection of hard limit traversal.
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*/
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static void
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xlog_cil_insert_pcp_aggregate(
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struct xfs_cil *cil,
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struct xfs_cil_ctx *ctx)
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{
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struct xlog_cil_pcp *cilpcp;
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int cpu;
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int count = 0;
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/* Trigger atomic updates then aggregate only for the first caller */
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if (!test_and_clear_bit(XLOG_CIL_PCP_SPACE, &cil->xc_flags))
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return;
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/*
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* We can race with other cpus setting cil_pcpmask. However, we've
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* atomically cleared PCP_SPACE which forces other threads to add to
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* the global space used count. cil_pcpmask is a superset of cilpcp
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* structures that could have a nonzero space_used.
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*/
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for_each_cpu(cpu, &ctx->cil_pcpmask) {
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int old, prev;
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cilpcp = per_cpu_ptr(cil->xc_pcp, cpu);
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do {
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old = cilpcp->space_used;
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prev = cmpxchg(&cilpcp->space_used, old, 0);
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} while (old != prev);
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count += old;
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}
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atomic_add(count, &ctx->space_used);
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}
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static void
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xlog_cil_ctx_switch(
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struct xfs_cil *cil,
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struct xfs_cil_ctx *ctx)
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{
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xlog_cil_set_iclog_hdr_count(cil);
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set_bit(XLOG_CIL_EMPTY, &cil->xc_flags);
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set_bit(XLOG_CIL_PCP_SPACE, &cil->xc_flags);
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ctx->sequence = ++cil->xc_current_sequence;
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ctx->cil = cil;
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cil->xc_ctx = ctx;
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}
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/*
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* After the first stage of log recovery is done, we know where the head and
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* tail of the log are. We need this log initialisation done before we can
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* initialise the first CIL checkpoint context.
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*
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* Here we allocate a log ticket to track space usage during a CIL push. This
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* ticket is passed to xlog_write() directly so that we don't slowly leak log
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* space by failing to account for space used by log headers and additional
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* region headers for split regions.
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*/
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void
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xlog_cil_init_post_recovery(
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struct xlog *log)
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{
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log->l_cilp->xc_ctx->ticket = xlog_cil_ticket_alloc(log);
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log->l_cilp->xc_ctx->sequence = 1;
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xlog_cil_set_iclog_hdr_count(log->l_cilp);
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}
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static inline int
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xlog_cil_iovec_space(
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uint niovecs)
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{
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return round_up((sizeof(struct xfs_log_vec) +
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niovecs * sizeof(struct xfs_log_iovec)),
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sizeof(uint64_t));
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}
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/*
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* Allocate or pin log vector buffers for CIL insertion.
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*
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* The CIL currently uses disposable buffers for copying a snapshot of the
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* modified items into the log during a push. The biggest problem with this is
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* the requirement to allocate the disposable buffer during the commit if:
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* a) does not exist; or
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* b) it is too small
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*
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* If we do this allocation within xlog_cil_insert_format_items(), it is done
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* under the xc_ctx_lock, which means that a CIL push cannot occur during
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* the memory allocation. This means that we have a potential deadlock situation
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* under low memory conditions when we have lots of dirty metadata pinned in
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* the CIL and we need a CIL commit to occur to free memory.
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*
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* To avoid this, we need to move the memory allocation outside the
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* xc_ctx_lock, but because the log vector buffers are disposable, that opens
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* up a TOCTOU race condition w.r.t. the CIL committing and removing the log
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* vector buffers between the check and the formatting of the item into the
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* log vector buffer within the xc_ctx_lock.
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*
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* Because the log vector buffer needs to be unchanged during the CIL push
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* process, we cannot share the buffer between the transaction commit (which
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* modifies the buffer) and the CIL push context that is writing the changes
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* into the log. This means skipping preallocation of buffer space is
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* unreliable, but we most definitely do not want to be allocating and freeing
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* buffers unnecessarily during commits when overwrites can be done safely.
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*
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* The simplest solution to this problem is to allocate a shadow buffer when a
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* log item is committed for the second time, and then to only use this buffer
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* if necessary. The buffer can remain attached to the log item until such time
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* it is needed, and this is the buffer that is reallocated to match the size of
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* the incoming modification. Then during the formatting of the item we can swap
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* the active buffer with the new one if we can't reuse the existing buffer. We
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* don't free the old buffer as it may be reused on the next modification if
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* it's size is right, otherwise we'll free and reallocate it at that point.
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*
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* This function builds a vector for the changes in each log item in the
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* transaction. It then works out the length of the buffer needed for each log
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* item, allocates them and attaches the vector to the log item in preparation
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* for the formatting step which occurs under the xc_ctx_lock.
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*
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* While this means the memory footprint goes up, it avoids the repeated
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* alloc/free pattern that repeated modifications of an item would otherwise
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* cause, and hence minimises the CPU overhead of such behaviour.
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*/
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static void
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xlog_cil_alloc_shadow_bufs(
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struct xlog *log,
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struct xfs_trans *tp)
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{
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struct xfs_log_item *lip;
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list_for_each_entry(lip, &tp->t_items, li_trans) {
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struct xfs_log_vec *lv;
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int niovecs = 0;
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int nbytes = 0;
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int buf_size;
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bool ordered = false;
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/* Skip items which aren't dirty in this transaction. */
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if (!test_bit(XFS_LI_DIRTY, &lip->li_flags))
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continue;
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/* get number of vecs and size of data to be stored */
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lip->li_ops->iop_size(lip, &niovecs, &nbytes);
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/*
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* Ordered items need to be tracked but we do not wish to write
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* them. We need a logvec to track the object, but we do not
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* need an iovec or buffer to be allocated for copying data.
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*/
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if (niovecs == XFS_LOG_VEC_ORDERED) {
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ordered = true;
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niovecs = 0;
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nbytes = 0;
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}
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/*
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* We 64-bit align the length of each iovec so that the start of
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* the next one is naturally aligned. We'll need to account for
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* that slack space here.
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*
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* We also add the xlog_op_header to each region when
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* formatting, but that's not accounted to the size of the item
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* at this point. Hence we'll need an addition number of bytes
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* for each vector to hold an opheader.
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*
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* Then round nbytes up to 64-bit alignment so that the initial
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* buffer alignment is easy to calculate and verify.
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*/
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nbytes += niovecs *
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(sizeof(uint64_t) + sizeof(struct xlog_op_header));
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nbytes = round_up(nbytes, sizeof(uint64_t));
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/*
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* The data buffer needs to start 64-bit aligned, so round up
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* that space to ensure we can align it appropriately and not
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* overrun the buffer.
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*/
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buf_size = nbytes + xlog_cil_iovec_space(niovecs);
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/*
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* if we have no shadow buffer, or it is too small, we need to
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* reallocate it.
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*/
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if (!lip->li_lv_shadow ||
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buf_size > lip->li_lv_shadow->lv_size) {
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/*
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* We free and allocate here as a realloc would copy
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* unnecessary data. We don't use kvzalloc() for the
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* same reason - we don't need to zero the data area in
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* the buffer, only the log vector header and the iovec
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* storage.
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*/
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kmem_free(lip->li_lv_shadow);
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lv = xlog_kvmalloc(buf_size);
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memset(lv, 0, xlog_cil_iovec_space(niovecs));
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INIT_LIST_HEAD(&lv->lv_list);
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lv->lv_item = lip;
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lv->lv_size = buf_size;
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if (ordered)
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lv->lv_buf_len = XFS_LOG_VEC_ORDERED;
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else
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lv->lv_iovecp = (struct xfs_log_iovec *)&lv[1];
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lip->li_lv_shadow = lv;
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} else {
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/* same or smaller, optimise common overwrite case */
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lv = lip->li_lv_shadow;
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if (ordered)
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lv->lv_buf_len = XFS_LOG_VEC_ORDERED;
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else
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lv->lv_buf_len = 0;
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lv->lv_bytes = 0;
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}
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/* Ensure the lv is set up according to ->iop_size */
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lv->lv_niovecs = niovecs;
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/* The allocated data region lies beyond the iovec region */
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lv->lv_buf = (char *)lv + xlog_cil_iovec_space(niovecs);
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}
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}
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/*
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* Prepare the log item for insertion into the CIL. Calculate the difference in
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* log space it will consume, and if it is a new item pin it as well.
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*/
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STATIC void
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xfs_cil_prepare_item(
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struct xlog *log,
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struct xfs_log_vec *lv,
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struct xfs_log_vec *old_lv,
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int *diff_len)
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{
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/* Account for the new LV being passed in */
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if (lv->lv_buf_len != XFS_LOG_VEC_ORDERED)
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*diff_len += lv->lv_bytes;
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/*
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* If there is no old LV, this is the first time we've seen the item in
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* this CIL context and so we need to pin it. If we are replacing the
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* old_lv, then remove the space it accounts for and make it the shadow
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* buffer for later freeing. In both cases we are now switching to the
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* shadow buffer, so update the pointer to it appropriately.
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*/
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if (!old_lv) {
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if (lv->lv_item->li_ops->iop_pin)
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lv->lv_item->li_ops->iop_pin(lv->lv_item);
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lv->lv_item->li_lv_shadow = NULL;
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} else if (old_lv != lv) {
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ASSERT(lv->lv_buf_len != XFS_LOG_VEC_ORDERED);
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*diff_len -= old_lv->lv_bytes;
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lv->lv_item->li_lv_shadow = old_lv;
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}
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/* attach new log vector to log item */
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lv->lv_item->li_lv = lv;
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/*
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* If this is the first time the item is being committed to the
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* CIL, store the sequence number on the log item so we can
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* tell in future commits whether this is the first checkpoint
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* the item is being committed into.
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*/
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if (!lv->lv_item->li_seq)
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lv->lv_item->li_seq = log->l_cilp->xc_ctx->sequence;
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}
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/*
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* Format log item into a flat buffers
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*
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* For delayed logging, we need to hold a formatted buffer containing all the
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* changes on the log item. This enables us to relog the item in memory and
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* write it out asynchronously without needing to relock the object that was
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* modified at the time it gets written into the iclog.
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*
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* This function takes the prepared log vectors attached to each log item, and
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* formats the changes into the log vector buffer. The buffer it uses is
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* dependent on the current state of the vector in the CIL - the shadow lv is
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* guaranteed to be large enough for the current modification, but we will only
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* use that if we can't reuse the existing lv. If we can't reuse the existing
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* lv, then simple swap it out for the shadow lv. We don't free it - that is
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* done lazily either by th enext modification or the freeing of the log item.
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*
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* We don't set up region headers during this process; we simply copy the
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* regions into the flat buffer. We can do this because we still have to do a
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* formatting step to write the regions into the iclog buffer. Writing the
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* ophdrs during the iclog write means that we can support splitting large
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* regions across iclog boundares without needing a change in the format of the
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* item/region encapsulation.
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*
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* Hence what we need to do now is change the rewrite the vector array to point
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* to the copied region inside the buffer we just allocated. This allows us to
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* format the regions into the iclog as though they are being formatted
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* directly out of the objects themselves.
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*/
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static void
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xlog_cil_insert_format_items(
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struct xlog *log,
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struct xfs_trans *tp,
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int *diff_len)
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{
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struct xfs_log_item *lip;
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/* Bail out if we didn't find a log item. */
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if (list_empty(&tp->t_items)) {
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ASSERT(0);
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return;
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}
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list_for_each_entry(lip, &tp->t_items, li_trans) {
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struct xfs_log_vec *lv;
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struct xfs_log_vec *old_lv = NULL;
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struct xfs_log_vec *shadow;
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bool ordered = false;
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/* Skip items which aren't dirty in this transaction. */
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if (!test_bit(XFS_LI_DIRTY, &lip->li_flags))
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continue;
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/*
|
|
* The formatting size information is already attached to
|
|
* the shadow lv on the log item.
|
|
*/
|
|
shadow = lip->li_lv_shadow;
|
|
if (shadow->lv_buf_len == XFS_LOG_VEC_ORDERED)
|
|
ordered = true;
|
|
|
|
/* Skip items that do not have any vectors for writing */
|
|
if (!shadow->lv_niovecs && !ordered)
|
|
continue;
|
|
|
|
/* compare to existing item size */
|
|
old_lv = lip->li_lv;
|
|
if (lip->li_lv && shadow->lv_size <= lip->li_lv->lv_size) {
|
|
/* same or smaller, optimise common overwrite case */
|
|
lv = lip->li_lv;
|
|
|
|
if (ordered)
|
|
goto insert;
|
|
|
|
/*
|
|
* set the item up as though it is a new insertion so
|
|
* that the space reservation accounting is correct.
|
|
*/
|
|
*diff_len -= lv->lv_bytes;
|
|
|
|
/* Ensure the lv is set up according to ->iop_size */
|
|
lv->lv_niovecs = shadow->lv_niovecs;
|
|
|
|
/* reset the lv buffer information for new formatting */
|
|
lv->lv_buf_len = 0;
|
|
lv->lv_bytes = 0;
|
|
lv->lv_buf = (char *)lv +
|
|
xlog_cil_iovec_space(lv->lv_niovecs);
|
|
} else {
|
|
/* switch to shadow buffer! */
|
|
lv = shadow;
|
|
lv->lv_item = lip;
|
|
if (ordered) {
|
|
/* track as an ordered logvec */
|
|
ASSERT(lip->li_lv == NULL);
|
|
goto insert;
|
|
}
|
|
}
|
|
|
|
ASSERT(IS_ALIGNED((unsigned long)lv->lv_buf, sizeof(uint64_t)));
|
|
lip->li_ops->iop_format(lip, lv);
|
|
insert:
|
|
xfs_cil_prepare_item(log, lv, old_lv, diff_len);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The use of lockless waitqueue_active() requires that the caller has
|
|
* serialised itself against the wakeup call in xlog_cil_push_work(). That
|
|
* can be done by either holding the push lock or the context lock.
|
|
*/
|
|
static inline bool
|
|
xlog_cil_over_hard_limit(
|
|
struct xlog *log,
|
|
int32_t space_used)
|
|
{
|
|
if (waitqueue_active(&log->l_cilp->xc_push_wait))
|
|
return true;
|
|
if (space_used >= XLOG_CIL_BLOCKING_SPACE_LIMIT(log))
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Insert the log items into the CIL and calculate the difference in space
|
|
* consumed by the item. Add the space to the checkpoint ticket and calculate
|
|
* if the change requires additional log metadata. If it does, take that space
|
|
* as well. Remove the amount of space we added to the checkpoint ticket from
|
|
* the current transaction ticket so that the accounting works out correctly.
|
|
*/
|
|
static void
|
|
xlog_cil_insert_items(
|
|
struct xlog *log,
|
|
struct xfs_trans *tp,
|
|
uint32_t released_space)
|
|
{
|
|
struct xfs_cil *cil = log->l_cilp;
|
|
struct xfs_cil_ctx *ctx = cil->xc_ctx;
|
|
struct xfs_log_item *lip;
|
|
int len = 0;
|
|
int iovhdr_res = 0, split_res = 0, ctx_res = 0;
|
|
int space_used;
|
|
int order;
|
|
unsigned int cpu_nr;
|
|
struct xlog_cil_pcp *cilpcp;
|
|
|
|
ASSERT(tp);
|
|
|
|
/*
|
|
* We can do this safely because the context can't checkpoint until we
|
|
* are done so it doesn't matter exactly how we update the CIL.
|
|
*/
|
|
xlog_cil_insert_format_items(log, tp, &len);
|
|
|
|
/*
|
|
* Subtract the space released by intent cancelation from the space we
|
|
* consumed so that we remove it from the CIL space and add it back to
|
|
* the current transaction reservation context.
|
|
*/
|
|
len -= released_space;
|
|
|
|
/*
|
|
* Grab the per-cpu pointer for the CIL before we start any accounting.
|
|
* That ensures that we are running with pre-emption disabled and so we
|
|
* can't be scheduled away between split sample/update operations that
|
|
* are done without outside locking to serialise them.
|
|
*/
|
|
cpu_nr = get_cpu();
|
|
cilpcp = this_cpu_ptr(cil->xc_pcp);
|
|
|
|
/* Tell the future push that there was work added by this CPU. */
|
|
if (!cpumask_test_cpu(cpu_nr, &ctx->cil_pcpmask))
|
|
cpumask_test_and_set_cpu(cpu_nr, &ctx->cil_pcpmask);
|
|
|
|
/*
|
|
* We need to take the CIL checkpoint unit reservation on the first
|
|
* commit into the CIL. Test the XLOG_CIL_EMPTY bit first so we don't
|
|
* unnecessarily do an atomic op in the fast path here. We can clear the
|
|
* XLOG_CIL_EMPTY bit as we are under the xc_ctx_lock here and that
|
|
* needs to be held exclusively to reset the XLOG_CIL_EMPTY bit.
|
|
*/
|
|
if (test_bit(XLOG_CIL_EMPTY, &cil->xc_flags) &&
|
|
test_and_clear_bit(XLOG_CIL_EMPTY, &cil->xc_flags))
|
|
ctx_res = ctx->ticket->t_unit_res;
|
|
|
|
/*
|
|
* Check if we need to steal iclog headers. atomic_read() is not a
|
|
* locked atomic operation, so we can check the value before we do any
|
|
* real atomic ops in the fast path. If we've already taken the CIL unit
|
|
* reservation from this commit, we've already got one iclog header
|
|
* space reserved so we have to account for that otherwise we risk
|
|
* overrunning the reservation on this ticket.
|
|
*
|
|
* If the CIL is already at the hard limit, we might need more header
|
|
* space that originally reserved. So steal more header space from every
|
|
* commit that occurs once we are over the hard limit to ensure the CIL
|
|
* push won't run out of reservation space.
|
|
*
|
|
* This can steal more than we need, but that's OK.
|
|
*
|
|
* The cil->xc_ctx_lock provides the serialisation necessary for safely
|
|
* calling xlog_cil_over_hard_limit() in this context.
|
|
*/
|
|
space_used = atomic_read(&ctx->space_used) + cilpcp->space_used + len;
|
|
if (atomic_read(&cil->xc_iclog_hdrs) > 0 ||
|
|
xlog_cil_over_hard_limit(log, space_used)) {
|
|
split_res = log->l_iclog_hsize +
|
|
sizeof(struct xlog_op_header);
|
|
if (ctx_res)
|
|
ctx_res += split_res * (tp->t_ticket->t_iclog_hdrs - 1);
|
|
else
|
|
ctx_res = split_res * tp->t_ticket->t_iclog_hdrs;
|
|
atomic_sub(tp->t_ticket->t_iclog_hdrs, &cil->xc_iclog_hdrs);
|
|
}
|
|
cilpcp->space_reserved += ctx_res;
|
|
|
|
/*
|
|
* Accurately account when over the soft limit, otherwise fold the
|
|
* percpu count into the global count if over the per-cpu threshold.
|
|
*/
|
|
if (!test_bit(XLOG_CIL_PCP_SPACE, &cil->xc_flags)) {
|
|
atomic_add(len, &ctx->space_used);
|
|
} else if (cilpcp->space_used + len >
|
|
(XLOG_CIL_SPACE_LIMIT(log) / num_online_cpus())) {
|
|
space_used = atomic_add_return(cilpcp->space_used + len,
|
|
&ctx->space_used);
|
|
cilpcp->space_used = 0;
|
|
|
|
/*
|
|
* If we just transitioned over the soft limit, we need to
|
|
* transition to the global atomic counter.
|
|
*/
|
|
if (space_used >= XLOG_CIL_SPACE_LIMIT(log))
|
|
xlog_cil_insert_pcp_aggregate(cil, ctx);
|
|
} else {
|
|
cilpcp->space_used += len;
|
|
}
|
|
/* attach the transaction to the CIL if it has any busy extents */
|
|
if (!list_empty(&tp->t_busy))
|
|
list_splice_init(&tp->t_busy, &cilpcp->busy_extents);
|
|
|
|
/*
|
|
* Now update the order of everything modified in the transaction
|
|
* and insert items into the CIL if they aren't already there.
|
|
* We do this here so we only need to take the CIL lock once during
|
|
* the transaction commit.
|
|
*/
|
|
order = atomic_inc_return(&ctx->order_id);
|
|
list_for_each_entry(lip, &tp->t_items, li_trans) {
|
|
/* Skip items which aren't dirty in this transaction. */
|
|
if (!test_bit(XFS_LI_DIRTY, &lip->li_flags))
|
|
continue;
|
|
|
|
lip->li_order_id = order;
|
|
if (!list_empty(&lip->li_cil))
|
|
continue;
|
|
list_add_tail(&lip->li_cil, &cilpcp->log_items);
|
|
}
|
|
put_cpu();
|
|
|
|
/*
|
|
* If we've overrun the reservation, dump the tx details before we move
|
|
* the log items. Shutdown is imminent...
|
|
*/
|
|
tp->t_ticket->t_curr_res -= ctx_res + len;
|
|
if (WARN_ON(tp->t_ticket->t_curr_res < 0)) {
|
|
xfs_warn(log->l_mp, "Transaction log reservation overrun:");
|
|
xfs_warn(log->l_mp,
|
|
" log items: %d bytes (iov hdrs: %d bytes)",
|
|
len, iovhdr_res);
|
|
xfs_warn(log->l_mp, " split region headers: %d bytes",
|
|
split_res);
|
|
xfs_warn(log->l_mp, " ctx ticket: %d bytes", ctx_res);
|
|
xlog_print_trans(tp);
|
|
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
|
|
}
|
|
}
|
|
|
|
static void
|
|
xlog_cil_free_logvec(
|
|
struct list_head *lv_chain)
|
|
{
|
|
struct xfs_log_vec *lv;
|
|
|
|
while (!list_empty(lv_chain)) {
|
|
lv = list_first_entry(lv_chain, struct xfs_log_vec, lv_list);
|
|
list_del_init(&lv->lv_list);
|
|
kmem_free(lv);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Mark all items committed and clear busy extents. We free the log vector
|
|
* chains in a separate pass so that we unpin the log items as quickly as
|
|
* possible.
|
|
*/
|
|
static void
|
|
xlog_cil_committed(
|
|
struct xfs_cil_ctx *ctx)
|
|
{
|
|
struct xfs_mount *mp = ctx->cil->xc_log->l_mp;
|
|
bool abort = xlog_is_shutdown(ctx->cil->xc_log);
|
|
|
|
/*
|
|
* If the I/O failed, we're aborting the commit and already shutdown.
|
|
* Wake any commit waiters before aborting the log items so we don't
|
|
* block async log pushers on callbacks. Async log pushers explicitly do
|
|
* not wait on log force completion because they may be holding locks
|
|
* required to unpin items.
|
|
*/
|
|
if (abort) {
|
|
spin_lock(&ctx->cil->xc_push_lock);
|
|
wake_up_all(&ctx->cil->xc_start_wait);
|
|
wake_up_all(&ctx->cil->xc_commit_wait);
|
|
spin_unlock(&ctx->cil->xc_push_lock);
|
|
}
|
|
|
|
xfs_trans_committed_bulk(ctx->cil->xc_log->l_ailp, &ctx->lv_chain,
|
|
ctx->start_lsn, abort);
|
|
|
|
xfs_extent_busy_sort(&ctx->busy_extents.extent_list);
|
|
xfs_extent_busy_clear(mp, &ctx->busy_extents.extent_list,
|
|
xfs_has_discard(mp) && !abort);
|
|
|
|
spin_lock(&ctx->cil->xc_push_lock);
|
|
list_del(&ctx->committing);
|
|
spin_unlock(&ctx->cil->xc_push_lock);
|
|
|
|
xlog_cil_free_logvec(&ctx->lv_chain);
|
|
|
|
if (!list_empty(&ctx->busy_extents.extent_list)) {
|
|
ctx->busy_extents.mount = mp;
|
|
ctx->busy_extents.owner = ctx;
|
|
xfs_discard_extents(mp, &ctx->busy_extents);
|
|
return;
|
|
}
|
|
|
|
kmem_free(ctx);
|
|
}
|
|
|
|
void
|
|
xlog_cil_process_committed(
|
|
struct list_head *list)
|
|
{
|
|
struct xfs_cil_ctx *ctx;
|
|
|
|
while ((ctx = list_first_entry_or_null(list,
|
|
struct xfs_cil_ctx, iclog_entry))) {
|
|
list_del(&ctx->iclog_entry);
|
|
xlog_cil_committed(ctx);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Record the LSN of the iclog we were just granted space to start writing into.
|
|
* If the context doesn't have a start_lsn recorded, then this iclog will
|
|
* contain the start record for the checkpoint. Otherwise this write contains
|
|
* the commit record for the checkpoint.
|
|
*/
|
|
void
|
|
xlog_cil_set_ctx_write_state(
|
|
struct xfs_cil_ctx *ctx,
|
|
struct xlog_in_core *iclog)
|
|
{
|
|
struct xfs_cil *cil = ctx->cil;
|
|
xfs_lsn_t lsn = be64_to_cpu(iclog->ic_header.h_lsn);
|
|
|
|
ASSERT(!ctx->commit_lsn);
|
|
if (!ctx->start_lsn) {
|
|
spin_lock(&cil->xc_push_lock);
|
|
/*
|
|
* The LSN we need to pass to the log items on transaction
|
|
* commit is the LSN reported by the first log vector write, not
|
|
* the commit lsn. If we use the commit record lsn then we can
|
|
* move the grant write head beyond the tail LSN and overwrite
|
|
* it.
|
|
*/
|
|
ctx->start_lsn = lsn;
|
|
wake_up_all(&cil->xc_start_wait);
|
|
spin_unlock(&cil->xc_push_lock);
|
|
|
|
/*
|
|
* Make sure the metadata we are about to overwrite in the log
|
|
* has been flushed to stable storage before this iclog is
|
|
* issued.
|
|
*/
|
|
spin_lock(&cil->xc_log->l_icloglock);
|
|
iclog->ic_flags |= XLOG_ICL_NEED_FLUSH;
|
|
spin_unlock(&cil->xc_log->l_icloglock);
|
|
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);
|
|
}
|
|
|
|
|
|
/*
|
|
* Ensure that the order of log writes follows checkpoint sequence order. This
|
|
* relies on the context LSN being zero until the log write has guaranteed the
|
|
* LSN that the log write will start at via xlog_state_get_iclog_space().
|
|
*/
|
|
enum _record_type {
|
|
_START_RECORD,
|
|
_COMMIT_RECORD,
|
|
};
|
|
|
|
static int
|
|
xlog_cil_order_write(
|
|
struct xfs_cil *cil,
|
|
xfs_csn_t sequence,
|
|
enum _record_type record)
|
|
{
|
|
struct xfs_cil_ctx *ctx;
|
|
|
|
restart:
|
|
spin_lock(&cil->xc_push_lock);
|
|
list_for_each_entry(ctx, &cil->xc_committing, committing) {
|
|
/*
|
|
* Avoid getting stuck in this loop because we were woken by the
|
|
* shutdown, but then went back to sleep once already in the
|
|
* shutdown state.
|
|
*/
|
|
if (xlog_is_shutdown(cil->xc_log)) {
|
|
spin_unlock(&cil->xc_push_lock);
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* Higher sequences will wait for this one so skip them.
|
|
* Don't wait for our own sequence, either.
|
|
*/
|
|
if (ctx->sequence >= sequence)
|
|
continue;
|
|
|
|
/* Wait until the LSN for the record has been recorded. */
|
|
switch (record) {
|
|
case _START_RECORD:
|
|
if (!ctx->start_lsn) {
|
|
xlog_wait(&cil->xc_start_wait, &cil->xc_push_lock);
|
|
goto restart;
|
|
}
|
|
break;
|
|
case _COMMIT_RECORD:
|
|
if (!ctx->commit_lsn) {
|
|
xlog_wait(&cil->xc_commit_wait, &cil->xc_push_lock);
|
|
goto restart;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock(&cil->xc_push_lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Write out the log vector change now attached to the CIL context. This will
|
|
* write a start record that needs to be strictly ordered in ascending CIL
|
|
* sequence order so that log recovery will always use in-order start LSNs when
|
|
* replaying checkpoints.
|
|
*/
|
|
static int
|
|
xlog_cil_write_chain(
|
|
struct xfs_cil_ctx *ctx,
|
|
uint32_t chain_len)
|
|
{
|
|
struct xlog *log = ctx->cil->xc_log;
|
|
int error;
|
|
|
|
error = xlog_cil_order_write(ctx->cil, ctx->sequence, _START_RECORD);
|
|
if (error)
|
|
return error;
|
|
return xlog_write(log, ctx, &ctx->lv_chain, ctx->ticket, chain_len);
|
|
}
|
|
|
|
/*
|
|
* Write out the commit record of a checkpoint transaction to close off a
|
|
* running log write. These commit records are strictly ordered in ascending CIL
|
|
* sequence order so that log recovery will always replay the checkpoints in the
|
|
* correct order.
|
|
*/
|
|
static int
|
|
xlog_cil_write_commit_record(
|
|
struct xfs_cil_ctx *ctx)
|
|
{
|
|
struct xlog *log = ctx->cil->xc_log;
|
|
struct xlog_op_header ophdr = {
|
|
.oh_clientid = XFS_TRANSACTION,
|
|
.oh_tid = cpu_to_be32(ctx->ticket->t_tid),
|
|
.oh_flags = XLOG_COMMIT_TRANS,
|
|
};
|
|
struct xfs_log_iovec reg = {
|
|
.i_addr = &ophdr,
|
|
.i_len = sizeof(struct xlog_op_header),
|
|
.i_type = XLOG_REG_TYPE_COMMIT,
|
|
};
|
|
struct xfs_log_vec vec = {
|
|
.lv_niovecs = 1,
|
|
.lv_iovecp = ®,
|
|
};
|
|
int error;
|
|
LIST_HEAD(lv_chain);
|
|
list_add(&vec.lv_list, &lv_chain);
|
|
|
|
if (xlog_is_shutdown(log))
|
|
return -EIO;
|
|
|
|
error = xlog_cil_order_write(ctx->cil, ctx->sequence, _COMMIT_RECORD);
|
|
if (error)
|
|
return error;
|
|
|
|
/* account for space used by record data */
|
|
ctx->ticket->t_curr_res -= reg.i_len;
|
|
error = xlog_write(log, ctx, &lv_chain, ctx->ticket, reg.i_len);
|
|
if (error)
|
|
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
|
|
return error;
|
|
}
|
|
|
|
struct xlog_cil_trans_hdr {
|
|
struct xlog_op_header oph[2];
|
|
struct xfs_trans_header thdr;
|
|
struct xfs_log_iovec lhdr[2];
|
|
};
|
|
|
|
/*
|
|
* Build a checkpoint transaction header to begin the journal transaction. We
|
|
* need to account for the space used by the transaction header here as it is
|
|
* not accounted for in xlog_write().
|
|
*
|
|
* This is the only place we write a transaction header, so we also build the
|
|
* log opheaders that indicate the start of a log transaction and wrap the
|
|
* transaction header. We keep the start record in it's own log vector rather
|
|
* than compacting them into a single region as this ends up making the logic
|
|
* in xlog_write() for handling empty opheaders for start, commit and unmount
|
|
* records much simpler.
|
|
*/
|
|
static void
|
|
xlog_cil_build_trans_hdr(
|
|
struct xfs_cil_ctx *ctx,
|
|
struct xlog_cil_trans_hdr *hdr,
|
|
struct xfs_log_vec *lvhdr,
|
|
int num_iovecs)
|
|
{
|
|
struct xlog_ticket *tic = ctx->ticket;
|
|
__be32 tid = cpu_to_be32(tic->t_tid);
|
|
|
|
memset(hdr, 0, sizeof(*hdr));
|
|
|
|
/* Log start record */
|
|
hdr->oph[0].oh_tid = tid;
|
|
hdr->oph[0].oh_clientid = XFS_TRANSACTION;
|
|
hdr->oph[0].oh_flags = XLOG_START_TRANS;
|
|
|
|
/* log iovec region pointer */
|
|
hdr->lhdr[0].i_addr = &hdr->oph[0];
|
|
hdr->lhdr[0].i_len = sizeof(struct xlog_op_header);
|
|
hdr->lhdr[0].i_type = XLOG_REG_TYPE_LRHEADER;
|
|
|
|
/* log opheader */
|
|
hdr->oph[1].oh_tid = tid;
|
|
hdr->oph[1].oh_clientid = XFS_TRANSACTION;
|
|
hdr->oph[1].oh_len = cpu_to_be32(sizeof(struct xfs_trans_header));
|
|
|
|
/* transaction header in host byte order format */
|
|
hdr->thdr.th_magic = XFS_TRANS_HEADER_MAGIC;
|
|
hdr->thdr.th_type = XFS_TRANS_CHECKPOINT;
|
|
hdr->thdr.th_tid = tic->t_tid;
|
|
hdr->thdr.th_num_items = num_iovecs;
|
|
|
|
/* log iovec region pointer */
|
|
hdr->lhdr[1].i_addr = &hdr->oph[1];
|
|
hdr->lhdr[1].i_len = sizeof(struct xlog_op_header) +
|
|
sizeof(struct xfs_trans_header);
|
|
hdr->lhdr[1].i_type = XLOG_REG_TYPE_TRANSHDR;
|
|
|
|
lvhdr->lv_niovecs = 2;
|
|
lvhdr->lv_iovecp = &hdr->lhdr[0];
|
|
lvhdr->lv_bytes = hdr->lhdr[0].i_len + hdr->lhdr[1].i_len;
|
|
|
|
tic->t_curr_res -= lvhdr->lv_bytes;
|
|
}
|
|
|
|
/*
|
|
* CIL item reordering compare function. We want to order in ascending ID order,
|
|
* but we want to leave items with the same ID in the order they were added to
|
|
* the list. This is important for operations like reflink where we log 4 order
|
|
* dependent intents in a single transaction when we overwrite an existing
|
|
* shared extent with a new shared extent. i.e. BUI(unmap), CUI(drop),
|
|
* CUI (inc), BUI(remap)...
|
|
*/
|
|
static int
|
|
xlog_cil_order_cmp(
|
|
void *priv,
|
|
const struct list_head *a,
|
|
const struct list_head *b)
|
|
{
|
|
struct xfs_log_vec *l1 = container_of(a, struct xfs_log_vec, lv_list);
|
|
struct xfs_log_vec *l2 = container_of(b, struct xfs_log_vec, lv_list);
|
|
|
|
return l1->lv_order_id > l2->lv_order_id;
|
|
}
|
|
|
|
/*
|
|
* Pull all the log vectors off the items in the CIL, and remove the items from
|
|
* the CIL. We don't need the CIL lock here because it's only needed on the
|
|
* transaction commit side which is currently locked out by the flush lock.
|
|
*
|
|
* If a log item is marked with a whiteout, we do not need to write it to the
|
|
* journal and so we just move them to the whiteout list for the caller to
|
|
* dispose of appropriately.
|
|
*/
|
|
static void
|
|
xlog_cil_build_lv_chain(
|
|
struct xfs_cil_ctx *ctx,
|
|
struct list_head *whiteouts,
|
|
uint32_t *num_iovecs,
|
|
uint32_t *num_bytes)
|
|
{
|
|
while (!list_empty(&ctx->log_items)) {
|
|
struct xfs_log_item *item;
|
|
struct xfs_log_vec *lv;
|
|
|
|
item = list_first_entry(&ctx->log_items,
|
|
struct xfs_log_item, li_cil);
|
|
|
|
if (test_bit(XFS_LI_WHITEOUT, &item->li_flags)) {
|
|
list_move(&item->li_cil, whiteouts);
|
|
trace_xfs_cil_whiteout_skip(item);
|
|
continue;
|
|
}
|
|
|
|
lv = item->li_lv;
|
|
lv->lv_order_id = item->li_order_id;
|
|
|
|
/* we don't write ordered log vectors */
|
|
if (lv->lv_buf_len != XFS_LOG_VEC_ORDERED)
|
|
*num_bytes += lv->lv_bytes;
|
|
*num_iovecs += lv->lv_niovecs;
|
|
list_add_tail(&lv->lv_list, &ctx->lv_chain);
|
|
|
|
list_del_init(&item->li_cil);
|
|
item->li_order_id = 0;
|
|
item->li_lv = NULL;
|
|
}
|
|
}
|
|
|
|
static void
|
|
xlog_cil_cleanup_whiteouts(
|
|
struct list_head *whiteouts)
|
|
{
|
|
while (!list_empty(whiteouts)) {
|
|
struct xfs_log_item *item = list_first_entry(whiteouts,
|
|
struct xfs_log_item, li_cil);
|
|
list_del_init(&item->li_cil);
|
|
trace_xfs_cil_whiteout_unpin(item);
|
|
item->li_ops->iop_unpin(item, 1);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Push the Committed Item List to the log.
|
|
*
|
|
* If the current sequence is the same as xc_push_seq we need to do a flush. If
|
|
* xc_push_seq is less than the current sequence, then it has already been
|
|
* flushed and we don't need to do anything - the caller will wait for it to
|
|
* complete if necessary.
|
|
*
|
|
* xc_push_seq is checked unlocked against the sequence number for a match.
|
|
* Hence we can allow log forces to run racily and not issue pushes for the
|
|
* same sequence twice. If we get a race between multiple pushes for the same
|
|
* sequence they will block on the first one and then abort, hence avoiding
|
|
* needless pushes.
|
|
*/
|
|
static void
|
|
xlog_cil_push_work(
|
|
struct work_struct *work)
|
|
{
|
|
struct xfs_cil_ctx *ctx =
|
|
container_of(work, struct xfs_cil_ctx, push_work);
|
|
struct xfs_cil *cil = ctx->cil;
|
|
struct xlog *log = cil->xc_log;
|
|
struct xfs_cil_ctx *new_ctx;
|
|
int num_iovecs = 0;
|
|
int num_bytes = 0;
|
|
int error = 0;
|
|
struct xlog_cil_trans_hdr thdr;
|
|
struct xfs_log_vec lvhdr = {};
|
|
xfs_csn_t push_seq;
|
|
bool push_commit_stable;
|
|
LIST_HEAD (whiteouts);
|
|
struct xlog_ticket *ticket;
|
|
|
|
new_ctx = xlog_cil_ctx_alloc();
|
|
new_ctx->ticket = xlog_cil_ticket_alloc(log);
|
|
|
|
down_write(&cil->xc_ctx_lock);
|
|
|
|
spin_lock(&cil->xc_push_lock);
|
|
push_seq = cil->xc_push_seq;
|
|
ASSERT(push_seq <= ctx->sequence);
|
|
push_commit_stable = cil->xc_push_commit_stable;
|
|
cil->xc_push_commit_stable = false;
|
|
|
|
/*
|
|
* As we are about to switch to a new, empty CIL context, we no longer
|
|
* need to throttle tasks on CIL space overruns. Wake any waiters that
|
|
* the hard push throttle may have caught so they can start committing
|
|
* to the new context. The ctx->xc_push_lock provides the serialisation
|
|
* necessary for safely using the lockless waitqueue_active() check in
|
|
* this context.
|
|
*/
|
|
if (waitqueue_active(&cil->xc_push_wait))
|
|
wake_up_all(&cil->xc_push_wait);
|
|
|
|
xlog_cil_push_pcp_aggregate(cil, ctx);
|
|
|
|
/*
|
|
* Check if we've anything to push. If there is nothing, then we don't
|
|
* move on to a new sequence number and so we have to be able to push
|
|
* this sequence again later.
|
|
*/
|
|
if (test_bit(XLOG_CIL_EMPTY, &cil->xc_flags)) {
|
|
cil->xc_push_seq = 0;
|
|
spin_unlock(&cil->xc_push_lock);
|
|
goto out_skip;
|
|
}
|
|
|
|
|
|
/* check for a previously pushed sequence */
|
|
if (push_seq < ctx->sequence) {
|
|
spin_unlock(&cil->xc_push_lock);
|
|
goto out_skip;
|
|
}
|
|
|
|
/*
|
|
* We are now going to push this context, so add it to the committing
|
|
* list before we do anything else. This ensures that anyone waiting on
|
|
* this push can easily detect the difference between a "push in
|
|
* progress" and "CIL is empty, nothing to do".
|
|
*
|
|
* IOWs, a wait loop can now check for:
|
|
* the current sequence not being found on the committing list;
|
|
* an empty CIL; and
|
|
* an unchanged sequence number
|
|
* to detect a push that had nothing to do and therefore does not need
|
|
* waiting on. If the CIL is not empty, we get put on the committing
|
|
* list before emptying the CIL and bumping the sequence number. Hence
|
|
* an empty CIL and an unchanged sequence number means we jumped out
|
|
* above after doing nothing.
|
|
*
|
|
* Hence the waiter will either find the commit sequence on the
|
|
* committing list or the sequence number will be unchanged and the CIL
|
|
* still dirty. In that latter case, the push has not yet started, and
|
|
* so the waiter will have to continue trying to check the CIL
|
|
* committing list until it is found. In extreme cases of delay, the
|
|
* sequence may fully commit between the attempts the wait makes to wait
|
|
* on the commit sequence.
|
|
*/
|
|
list_add(&ctx->committing, &cil->xc_committing);
|
|
spin_unlock(&cil->xc_push_lock);
|
|
|
|
xlog_cil_build_lv_chain(ctx, &whiteouts, &num_iovecs, &num_bytes);
|
|
|
|
/*
|
|
* Switch the contexts so we can drop the context lock and move out
|
|
* of a shared context. We can't just go straight to the commit record,
|
|
* though - we need to synchronise with previous and future commits so
|
|
* that the commit records are correctly ordered in the log to ensure
|
|
* that we process items during log IO completion in the correct order.
|
|
*
|
|
* For example, if we get an EFI in one checkpoint and the EFD in the
|
|
* next (e.g. due to log forces), we do not want the checkpoint with
|
|
* the EFD to be committed before the checkpoint with the EFI. Hence
|
|
* we must strictly order the commit records of the checkpoints so
|
|
* that: a) the checkpoint callbacks are attached to the iclogs in the
|
|
* correct order; and b) the checkpoints are replayed in correct order
|
|
* in log recovery.
|
|
*
|
|
* Hence we need to add this context to the committing context list so
|
|
* that higher sequences will wait for us to write out a commit record
|
|
* before they do.
|
|
*
|
|
* xfs_log_force_seq requires us to mirror the new sequence into the cil
|
|
* structure atomically with the addition of this sequence to the
|
|
* committing list. This also ensures that we can do unlocked checks
|
|
* against the current sequence in log forces without risking
|
|
* deferencing a freed context pointer.
|
|
*/
|
|
spin_lock(&cil->xc_push_lock);
|
|
xlog_cil_ctx_switch(cil, new_ctx);
|
|
spin_unlock(&cil->xc_push_lock);
|
|
up_write(&cil->xc_ctx_lock);
|
|
|
|
/*
|
|
* Sort the log vector chain before we add the transaction headers.
|
|
* This ensures we always have the transaction headers at the start
|
|
* of the chain.
|
|
*/
|
|
list_sort(NULL, &ctx->lv_chain, xlog_cil_order_cmp);
|
|
|
|
/*
|
|
* Build a checkpoint transaction header and write it to the log to
|
|
* begin the transaction. We need to account for the space used by the
|
|
* transaction header here as it is not accounted for in xlog_write().
|
|
* Add the lvhdr to the head of the lv chain we pass to xlog_write() so
|
|
* it gets written into the iclog first.
|
|
*/
|
|
xlog_cil_build_trans_hdr(ctx, &thdr, &lvhdr, num_iovecs);
|
|
num_bytes += lvhdr.lv_bytes;
|
|
list_add(&lvhdr.lv_list, &ctx->lv_chain);
|
|
|
|
/*
|
|
* Take the lvhdr back off the lv_chain immediately after calling
|
|
* xlog_cil_write_chain() as it should not be passed to log IO
|
|
* completion.
|
|
*/
|
|
error = xlog_cil_write_chain(ctx, num_bytes);
|
|
list_del(&lvhdr.lv_list);
|
|
if (error)
|
|
goto out_abort_free_ticket;
|
|
|
|
error = xlog_cil_write_commit_record(ctx);
|
|
if (error)
|
|
goto out_abort_free_ticket;
|
|
|
|
/*
|
|
* Grab the ticket from the ctx so we can ungrant it after releasing the
|
|
* commit_iclog. The ctx may be freed by the time we return from
|
|
* releasing the commit_iclog (i.e. checkpoint has been completed and
|
|
* callback run) so we can't reference the ctx after the call to
|
|
* xlog_state_release_iclog().
|
|
*/
|
|
ticket = ctx->ticket;
|
|
|
|
/*
|
|
* If the checkpoint spans multiple iclogs, wait for all previous iclogs
|
|
* to complete before we submit the commit_iclog. We can't use state
|
|
* checks for this - ACTIVE can be either a past completed iclog or a
|
|
* future iclog being filled, while WANT_SYNC through SYNC_DONE can be a
|
|
* past or future iclog awaiting IO or ordered IO completion to be run.
|
|
* In the latter case, if it's a future iclog and we wait on it, the we
|
|
* will hang because it won't get processed through to ic_force_wait
|
|
* wakeup until this commit_iclog is written to disk. Hence we use the
|
|
* 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(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(ctx->commit_iclog->ic_prev);
|
|
spin_lock(&log->l_icloglock);
|
|
}
|
|
|
|
/*
|
|
* We need to issue a pre-flush so that the ordering for this
|
|
* checkpoint is correctly preserved down to stable storage.
|
|
*/
|
|
ctx->commit_iclog->ic_flags |= XLOG_ICL_NEED_FLUSH;
|
|
}
|
|
|
|
/*
|
|
* The commit iclog must be written to stable storage to guarantee
|
|
* journal IO vs metadata writeback IO is correctly ordered on stable
|
|
* storage.
|
|
*
|
|
* If the push caller needs the commit to be immediately stable and the
|
|
* commit_iclog is not yet marked as XLOG_STATE_WANT_SYNC to indicate it
|
|
* will be written when released, switch it's state to WANT_SYNC right
|
|
* now.
|
|
*/
|
|
ctx->commit_iclog->ic_flags |= XLOG_ICL_NEED_FUA;
|
|
if (push_commit_stable &&
|
|
ctx->commit_iclog->ic_state == XLOG_STATE_ACTIVE)
|
|
xlog_state_switch_iclogs(log, ctx->commit_iclog, 0);
|
|
ticket = ctx->ticket;
|
|
xlog_state_release_iclog(log, ctx->commit_iclog, ticket);
|
|
|
|
/* Not safe to reference ctx now! */
|
|
|
|
spin_unlock(&log->l_icloglock);
|
|
xlog_cil_cleanup_whiteouts(&whiteouts);
|
|
xfs_log_ticket_ungrant(log, ticket);
|
|
return;
|
|
|
|
out_skip:
|
|
up_write(&cil->xc_ctx_lock);
|
|
xfs_log_ticket_put(new_ctx->ticket);
|
|
kmem_free(new_ctx);
|
|
return;
|
|
|
|
out_abort_free_ticket:
|
|
ASSERT(xlog_is_shutdown(log));
|
|
xlog_cil_cleanup_whiteouts(&whiteouts);
|
|
if (!ctx->commit_iclog) {
|
|
xfs_log_ticket_ungrant(log, ctx->ticket);
|
|
xlog_cil_committed(ctx);
|
|
return;
|
|
}
|
|
spin_lock(&log->l_icloglock);
|
|
ticket = ctx->ticket;
|
|
xlog_state_release_iclog(log, ctx->commit_iclog, ticket);
|
|
/* Not safe to reference ctx now! */
|
|
spin_unlock(&log->l_icloglock);
|
|
xfs_log_ticket_ungrant(log, ticket);
|
|
}
|
|
|
|
/*
|
|
* We need to push CIL every so often so we don't cache more than we can fit in
|
|
* the log. The limit really is that a checkpoint can't be more than half the
|
|
* log (the current checkpoint is not allowed to overwrite the previous
|
|
* checkpoint), but commit latency and memory usage limit this to a smaller
|
|
* size.
|
|
*/
|
|
static void
|
|
xlog_cil_push_background(
|
|
struct xlog *log) __releases(cil->xc_ctx_lock)
|
|
{
|
|
struct xfs_cil *cil = log->l_cilp;
|
|
int space_used = atomic_read(&cil->xc_ctx->space_used);
|
|
|
|
/*
|
|
* The cil won't be empty because we are called while holding the
|
|
* context lock so whatever we added to the CIL will still be there.
|
|
*/
|
|
ASSERT(!test_bit(XLOG_CIL_EMPTY, &cil->xc_flags));
|
|
|
|
/*
|
|
* We are done if:
|
|
* - we haven't used up all the space available yet; or
|
|
* - we've already queued up a push; and
|
|
* - we're not over the hard limit; and
|
|
* - nothing has been over the hard limit.
|
|
*
|
|
* If so, we don't need to take the push lock as there's nothing to do.
|
|
*/
|
|
if (space_used < XLOG_CIL_SPACE_LIMIT(log) ||
|
|
(cil->xc_push_seq == cil->xc_current_sequence &&
|
|
space_used < XLOG_CIL_BLOCKING_SPACE_LIMIT(log) &&
|
|
!waitqueue_active(&cil->xc_push_wait))) {
|
|
up_read(&cil->xc_ctx_lock);
|
|
return;
|
|
}
|
|
|
|
spin_lock(&cil->xc_push_lock);
|
|
if (cil->xc_push_seq < cil->xc_current_sequence) {
|
|
cil->xc_push_seq = cil->xc_current_sequence;
|
|
queue_work(cil->xc_push_wq, &cil->xc_ctx->push_work);
|
|
}
|
|
|
|
/*
|
|
* Drop the context lock now, we can't hold that if we need to sleep
|
|
* because we are over the blocking threshold. The push_lock is still
|
|
* held, so blocking threshold sleep/wakeup is still correctly
|
|
* serialised here.
|
|
*/
|
|
up_read(&cil->xc_ctx_lock);
|
|
|
|
/*
|
|
* If we are well over the space limit, throttle the work that is being
|
|
* done until the push work on this context has begun. Enforce the hard
|
|
* throttle on all transaction commits once it has been activated, even
|
|
* if the committing transactions have resulted in the space usage
|
|
* dipping back down under the hard limit.
|
|
*
|
|
* The ctx->xc_push_lock provides the serialisation necessary for safely
|
|
* calling xlog_cil_over_hard_limit() in this context.
|
|
*/
|
|
if (xlog_cil_over_hard_limit(log, space_used)) {
|
|
trace_xfs_log_cil_wait(log, cil->xc_ctx->ticket);
|
|
ASSERT(space_used < log->l_logsize);
|
|
xlog_wait(&cil->xc_push_wait, &cil->xc_push_lock);
|
|
return;
|
|
}
|
|
|
|
spin_unlock(&cil->xc_push_lock);
|
|
|
|
}
|
|
|
|
/*
|
|
* xlog_cil_push_now() is used to trigger an immediate CIL push to the sequence
|
|
* number that is passed. When it returns, the work will be queued for
|
|
* @push_seq, but it won't be completed.
|
|
*
|
|
* If the caller is performing a synchronous force, we will flush the workqueue
|
|
* to get previously queued work moving to minimise the wait time they will
|
|
* undergo waiting for all outstanding pushes to complete. The caller is
|
|
* expected to do the required waiting for push_seq to complete.
|
|
*
|
|
* If the caller is performing an async push, we need to ensure that the
|
|
* checkpoint is fully flushed out of the iclogs when we finish the push. If we
|
|
* don't do this, then the commit record may remain sitting in memory in an
|
|
* ACTIVE iclog. This then requires another full log force to push to disk,
|
|
* which defeats the purpose of having an async, non-blocking CIL force
|
|
* mechanism. Hence in this case we need to pass a flag to the push work to
|
|
* indicate it needs to flush the commit record itself.
|
|
*/
|
|
static void
|
|
xlog_cil_push_now(
|
|
struct xlog *log,
|
|
xfs_lsn_t push_seq,
|
|
bool async)
|
|
{
|
|
struct xfs_cil *cil = log->l_cilp;
|
|
|
|
if (!cil)
|
|
return;
|
|
|
|
ASSERT(push_seq && push_seq <= cil->xc_current_sequence);
|
|
|
|
/* start on any pending background push to minimise wait time on it */
|
|
if (!async)
|
|
flush_workqueue(cil->xc_push_wq);
|
|
|
|
spin_lock(&cil->xc_push_lock);
|
|
|
|
/*
|
|
* If this is an async flush request, we always need to set the
|
|
* xc_push_commit_stable flag even if something else has already queued
|
|
* a push. The flush caller is asking for the CIL to be on stable
|
|
* storage when the next push completes, so regardless of who has queued
|
|
* the push, the flush requires stable semantics from it.
|
|
*/
|
|
cil->xc_push_commit_stable = async;
|
|
|
|
/*
|
|
* If the CIL is empty or we've already pushed the sequence then
|
|
* there's no more work that we need to do.
|
|
*/
|
|
if (test_bit(XLOG_CIL_EMPTY, &cil->xc_flags) ||
|
|
push_seq <= cil->xc_push_seq) {
|
|
spin_unlock(&cil->xc_push_lock);
|
|
return;
|
|
}
|
|
|
|
cil->xc_push_seq = push_seq;
|
|
queue_work(cil->xc_push_wq, &cil->xc_ctx->push_work);
|
|
spin_unlock(&cil->xc_push_lock);
|
|
}
|
|
|
|
bool
|
|
xlog_cil_empty(
|
|
struct xlog *log)
|
|
{
|
|
struct xfs_cil *cil = log->l_cilp;
|
|
bool empty = false;
|
|
|
|
spin_lock(&cil->xc_push_lock);
|
|
if (test_bit(XLOG_CIL_EMPTY, &cil->xc_flags))
|
|
empty = true;
|
|
spin_unlock(&cil->xc_push_lock);
|
|
return empty;
|
|
}
|
|
|
|
/*
|
|
* If there are intent done items in this transaction and the related intent was
|
|
* committed in the current (same) CIL checkpoint, we don't need to write either
|
|
* the intent or intent done item to the journal as the change will be
|
|
* journalled atomically within this checkpoint. As we cannot remove items from
|
|
* the CIL here, mark the related intent with a whiteout so that the CIL push
|
|
* can remove it rather than writing it to the journal. Then remove the intent
|
|
* done item from the current transaction and release it so it doesn't get put
|
|
* into the CIL at all.
|
|
*/
|
|
static uint32_t
|
|
xlog_cil_process_intents(
|
|
struct xfs_cil *cil,
|
|
struct xfs_trans *tp)
|
|
{
|
|
struct xfs_log_item *lip, *ilip, *next;
|
|
uint32_t len = 0;
|
|
|
|
list_for_each_entry_safe(lip, next, &tp->t_items, li_trans) {
|
|
if (!(lip->li_ops->flags & XFS_ITEM_INTENT_DONE))
|
|
continue;
|
|
|
|
ilip = lip->li_ops->iop_intent(lip);
|
|
if (!ilip || !xlog_item_in_current_chkpt(cil, ilip))
|
|
continue;
|
|
set_bit(XFS_LI_WHITEOUT, &ilip->li_flags);
|
|
trace_xfs_cil_whiteout_mark(ilip);
|
|
len += ilip->li_lv->lv_bytes;
|
|
kmem_free(ilip->li_lv);
|
|
ilip->li_lv = NULL;
|
|
|
|
xfs_trans_del_item(lip);
|
|
lip->li_ops->iop_release(lip);
|
|
}
|
|
return len;
|
|
}
|
|
|
|
/*
|
|
* Commit a transaction with the given vector to the Committed Item List.
|
|
*
|
|
* To do this, we need to format the item, pin it in memory if required and
|
|
* account for the space used by the transaction. Once we have done that we
|
|
* need to release the unused reservation for the transaction, attach the
|
|
* transaction to the checkpoint context so we carry the busy extents through
|
|
* to checkpoint completion, and then unlock all the items in the transaction.
|
|
*
|
|
* Called with the context lock already held in read mode to lock out
|
|
* background commit, returns without it held once background commits are
|
|
* allowed again.
|
|
*/
|
|
void
|
|
xlog_cil_commit(
|
|
struct xlog *log,
|
|
struct xfs_trans *tp,
|
|
xfs_csn_t *commit_seq,
|
|
bool regrant)
|
|
{
|
|
struct xfs_cil *cil = log->l_cilp;
|
|
struct xfs_log_item *lip, *next;
|
|
uint32_t released_space = 0;
|
|
|
|
/*
|
|
* Do all necessary memory allocation before we lock the CIL.
|
|
* This ensures the allocation does not deadlock with a CIL
|
|
* push in memory reclaim (e.g. from kswapd).
|
|
*/
|
|
xlog_cil_alloc_shadow_bufs(log, tp);
|
|
|
|
/* lock out background commit */
|
|
down_read(&cil->xc_ctx_lock);
|
|
|
|
if (tp->t_flags & XFS_TRANS_HAS_INTENT_DONE)
|
|
released_space = xlog_cil_process_intents(cil, tp);
|
|
|
|
xlog_cil_insert_items(log, tp, released_space);
|
|
|
|
if (regrant && !xlog_is_shutdown(log))
|
|
xfs_log_ticket_regrant(log, tp->t_ticket);
|
|
else
|
|
xfs_log_ticket_ungrant(log, tp->t_ticket);
|
|
tp->t_ticket = NULL;
|
|
xfs_trans_unreserve_and_mod_sb(tp);
|
|
|
|
/*
|
|
* Once all the items of the transaction have been copied to the CIL,
|
|
* the items can be unlocked and possibly freed.
|
|
*
|
|
* This needs to be done before we drop the CIL context lock because we
|
|
* have to update state in the log items and unlock them before they go
|
|
* to disk. If we don't, then the CIL checkpoint can race with us and
|
|
* we can run checkpoint completion before we've updated and unlocked
|
|
* the log items. This affects (at least) processing of stale buffers,
|
|
* inodes and EFIs.
|
|
*/
|
|
trace_xfs_trans_commit_items(tp, _RET_IP_);
|
|
list_for_each_entry_safe(lip, next, &tp->t_items, li_trans) {
|
|
xfs_trans_del_item(lip);
|
|
if (lip->li_ops->iop_committing)
|
|
lip->li_ops->iop_committing(lip, cil->xc_ctx->sequence);
|
|
}
|
|
if (commit_seq)
|
|
*commit_seq = cil->xc_ctx->sequence;
|
|
|
|
/* xlog_cil_push_background() releases cil->xc_ctx_lock */
|
|
xlog_cil_push_background(log);
|
|
}
|
|
|
|
/*
|
|
* Flush the CIL to stable storage but don't wait for it to complete. This
|
|
* requires the CIL push to ensure the commit record for the push hits the disk,
|
|
* but otherwise is no different to a push done from a log force.
|
|
*/
|
|
void
|
|
xlog_cil_flush(
|
|
struct xlog *log)
|
|
{
|
|
xfs_csn_t seq = log->l_cilp->xc_current_sequence;
|
|
|
|
trace_xfs_log_force(log->l_mp, seq, _RET_IP_);
|
|
xlog_cil_push_now(log, seq, true);
|
|
|
|
/*
|
|
* If the CIL is empty, make sure that any previous checkpoint that may
|
|
* still be in an active iclog is pushed to stable storage.
|
|
*/
|
|
if (test_bit(XLOG_CIL_EMPTY, &log->l_cilp->xc_flags))
|
|
xfs_log_force(log->l_mp, 0);
|
|
}
|
|
|
|
/*
|
|
* Conditionally push the CIL based on the sequence passed in.
|
|
*
|
|
* We only need to push if we haven't already pushed the sequence number given.
|
|
* Hence the only time we will trigger a push here is if the push sequence is
|
|
* the same as the current context.
|
|
*
|
|
* We return the current commit lsn to allow the callers to determine if a
|
|
* iclog flush is necessary following this call.
|
|
*/
|
|
xfs_lsn_t
|
|
xlog_cil_force_seq(
|
|
struct xlog *log,
|
|
xfs_csn_t sequence)
|
|
{
|
|
struct xfs_cil *cil = log->l_cilp;
|
|
struct xfs_cil_ctx *ctx;
|
|
xfs_lsn_t commit_lsn = NULLCOMMITLSN;
|
|
|
|
ASSERT(sequence <= cil->xc_current_sequence);
|
|
|
|
if (!sequence)
|
|
sequence = cil->xc_current_sequence;
|
|
trace_xfs_log_force(log->l_mp, sequence, _RET_IP_);
|
|
|
|
/*
|
|
* check to see if we need to force out the current context.
|
|
* xlog_cil_push() handles racing pushes for the same sequence,
|
|
* so no need to deal with it here.
|
|
*/
|
|
restart:
|
|
xlog_cil_push_now(log, sequence, false);
|
|
|
|
/*
|
|
* See if we can find a previous sequence still committing.
|
|
* We need to wait for all previous sequence commits to complete
|
|
* before allowing the force of push_seq to go ahead. Hence block
|
|
* on commits for those as well.
|
|
*/
|
|
spin_lock(&cil->xc_push_lock);
|
|
list_for_each_entry(ctx, &cil->xc_committing, committing) {
|
|
/*
|
|
* Avoid getting stuck in this loop because we were woken by the
|
|
* shutdown, but then went back to sleep once already in the
|
|
* shutdown state.
|
|
*/
|
|
if (xlog_is_shutdown(log))
|
|
goto out_shutdown;
|
|
if (ctx->sequence > sequence)
|
|
continue;
|
|
if (!ctx->commit_lsn) {
|
|
/*
|
|
* It is still being pushed! Wait for the push to
|
|
* complete, then start again from the beginning.
|
|
*/
|
|
XFS_STATS_INC(log->l_mp, xs_log_force_sleep);
|
|
xlog_wait(&cil->xc_commit_wait, &cil->xc_push_lock);
|
|
goto restart;
|
|
}
|
|
if (ctx->sequence != sequence)
|
|
continue;
|
|
/* found it! */
|
|
commit_lsn = ctx->commit_lsn;
|
|
}
|
|
|
|
/*
|
|
* The call to xlog_cil_push_now() executes the push in the background.
|
|
* Hence by the time we have got here it our sequence may not have been
|
|
* pushed yet. This is true if the current sequence still matches the
|
|
* push sequence after the above wait loop and the CIL still contains
|
|
* dirty objects. This is guaranteed by the push code first adding the
|
|
* context to the committing list before emptying the CIL.
|
|
*
|
|
* Hence if we don't find the context in the committing list and the
|
|
* current sequence number is unchanged then the CIL contents are
|
|
* significant. If the CIL is empty, if means there was nothing to push
|
|
* and that means there is nothing to wait for. If the CIL is not empty,
|
|
* it means we haven't yet started the push, because if it had started
|
|
* we would have found the context on the committing list.
|
|
*/
|
|
if (sequence == cil->xc_current_sequence &&
|
|
!test_bit(XLOG_CIL_EMPTY, &cil->xc_flags)) {
|
|
spin_unlock(&cil->xc_push_lock);
|
|
goto restart;
|
|
}
|
|
|
|
spin_unlock(&cil->xc_push_lock);
|
|
return commit_lsn;
|
|
|
|
/*
|
|
* We detected a shutdown in progress. We need to trigger the log force
|
|
* to pass through it's iclog state machine error handling, even though
|
|
* we are already in a shutdown state. Hence we can't return
|
|
* NULLCOMMITLSN here as that has special meaning to log forces (i.e.
|
|
* LSN is already stable), so we return a zero LSN instead.
|
|
*/
|
|
out_shutdown:
|
|
spin_unlock(&cil->xc_push_lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Perform initial CIL structure initialisation.
|
|
*/
|
|
int
|
|
xlog_cil_init(
|
|
struct xlog *log)
|
|
{
|
|
struct xfs_cil *cil;
|
|
struct xfs_cil_ctx *ctx;
|
|
struct xlog_cil_pcp *cilpcp;
|
|
int cpu;
|
|
|
|
cil = kmem_zalloc(sizeof(*cil), KM_MAYFAIL);
|
|
if (!cil)
|
|
return -ENOMEM;
|
|
/*
|
|
* Limit the CIL pipeline depth to 4 concurrent works to bound the
|
|
* concurrency the log spinlocks will be exposed to.
|
|
*/
|
|
cil->xc_push_wq = alloc_workqueue("xfs-cil/%s",
|
|
XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM | WQ_UNBOUND),
|
|
4, log->l_mp->m_super->s_id);
|
|
if (!cil->xc_push_wq)
|
|
goto out_destroy_cil;
|
|
|
|
cil->xc_log = log;
|
|
cil->xc_pcp = alloc_percpu(struct xlog_cil_pcp);
|
|
if (!cil->xc_pcp)
|
|
goto out_destroy_wq;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
cilpcp = per_cpu_ptr(cil->xc_pcp, cpu);
|
|
INIT_LIST_HEAD(&cilpcp->busy_extents);
|
|
INIT_LIST_HEAD(&cilpcp->log_items);
|
|
}
|
|
|
|
INIT_LIST_HEAD(&cil->xc_committing);
|
|
spin_lock_init(&cil->xc_push_lock);
|
|
init_waitqueue_head(&cil->xc_push_wait);
|
|
init_rwsem(&cil->xc_ctx_lock);
|
|
init_waitqueue_head(&cil->xc_start_wait);
|
|
init_waitqueue_head(&cil->xc_commit_wait);
|
|
log->l_cilp = cil;
|
|
|
|
ctx = xlog_cil_ctx_alloc();
|
|
xlog_cil_ctx_switch(cil, ctx);
|
|
return 0;
|
|
|
|
out_destroy_wq:
|
|
destroy_workqueue(cil->xc_push_wq);
|
|
out_destroy_cil:
|
|
kmem_free(cil);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
void
|
|
xlog_cil_destroy(
|
|
struct xlog *log)
|
|
{
|
|
struct xfs_cil *cil = log->l_cilp;
|
|
|
|
if (cil->xc_ctx) {
|
|
if (cil->xc_ctx->ticket)
|
|
xfs_log_ticket_put(cil->xc_ctx->ticket);
|
|
kmem_free(cil->xc_ctx);
|
|
}
|
|
|
|
ASSERT(test_bit(XLOG_CIL_EMPTY, &cil->xc_flags));
|
|
free_percpu(cil->xc_pcp);
|
|
destroy_workqueue(cil->xc_push_wq);
|
|
kmem_free(cil);
|
|
}
|
|
|