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![Christoph Hellwig](/assets/img/avatar_default.png)
More on-disk format consolidation. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
998 lines
30 KiB
C
998 lines
30 KiB
C
/*
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* Copyright (c) 2010 Red Hat, Inc. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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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_error.h"
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#include "xfs_alloc.h"
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#include "xfs_extent_busy.h"
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#include "xfs_discard.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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/*
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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, XFS_TRANSACTION, 0,
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KM_SLEEP|KM_NOFS);
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tic->t_trans_type = XFS_TRANS_CHECKPOINT;
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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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return tic;
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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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}
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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 and vectors it will consume, and if it is a new item pin it as
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* 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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int *diff_iovecs)
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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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*diff_iovecs += lv->lv_niovecs;
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}
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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 free it.
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*/
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if (!old_lv)
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lv->lv_item->li_ops->iop_pin(lv->lv_item);
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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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*diff_iovecs -= old_lv->lv_niovecs;
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kmem_free(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 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 formats the vector for the item into the buffer.
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* The buffer is then attached to the log item are then inserted into the
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* Committed Item List for tracking until the next checkpoint is written out.
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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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int *diff_iovecs)
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{
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struct xfs_log_item_desc *lidp;
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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(lidp, &tp->t_items, lid_trans) {
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struct xfs_log_item *lip = lidp->lid_item;
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struct xfs_log_vec *lv;
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struct xfs_log_vec *old_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 (!(lidp->lid_flags & XFS_LID_DIRTY))
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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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/* Skip items that do not have any vectors for writing */
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if (!niovecs)
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continue;
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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
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* of the next one is naturally aligned. We'll need to
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* account for that slack space here. Then round nbytes up
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* to 64-bit alignment so that the initial buffer alignment is
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* easy to calculate and verify.
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*/
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nbytes += niovecs * sizeof(uint64_t);
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nbytes = round_up(nbytes, sizeof(uint64_t));
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/* grab the old item if it exists for reservation accounting */
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old_lv = lip->li_lv;
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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 +
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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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/* compare to existing item size */
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if (lip->li_lv && buf_size <= lip->li_lv->lv_size) {
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/* same or smaller, optimise common overwrite case */
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lv = lip->li_lv;
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lv->lv_next = NULL;
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if (ordered)
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goto insert;
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/*
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* set the item up as though it is a new insertion so
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* that the space reservation accounting is correct.
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*/
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*diff_iovecs -= lv->lv_niovecs;
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*diff_len -= lv->lv_bytes;
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} else {
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/* allocate new data chunk */
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lv = kmem_zalloc(buf_size, KM_SLEEP|KM_NOFS);
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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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/* track as an ordered logvec */
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ASSERT(lip->li_lv == NULL);
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lv->lv_buf_len = XFS_LOG_VEC_ORDERED;
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goto insert;
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}
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lv->lv_iovecp = (struct xfs_log_iovec *)&lv[1];
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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_len = 0;
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lv->lv_bytes = 0;
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lv->lv_buf = (char *)lv + buf_size - nbytes;
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ASSERT(IS_ALIGNED((unsigned long)lv->lv_buf, sizeof(uint64_t)));
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lip->li_ops->iop_format(lip, lv);
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insert:
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ASSERT(lv->lv_buf_len <= nbytes);
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xfs_cil_prepare_item(log, lv, old_lv, diff_len, diff_iovecs);
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}
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}
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/*
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* Insert the log items into the CIL and calculate the difference in space
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* consumed by the item. Add the space to the checkpoint ticket and calculate
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* if the change requires additional log metadata. If it does, take that space
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* as well. Remove the amount of space we added to the checkpoint ticket from
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* the current transaction ticket so that the accounting works out correctly.
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*/
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static void
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xlog_cil_insert_items(
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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_cil *cil = log->l_cilp;
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struct xfs_cil_ctx *ctx = cil->xc_ctx;
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struct xfs_log_item_desc *lidp;
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int len = 0;
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int diff_iovecs = 0;
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int iclog_space;
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ASSERT(tp);
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/*
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* We can do this safely because the context can't checkpoint until we
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* are done so it doesn't matter exactly how we update the CIL.
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*/
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xlog_cil_insert_format_items(log, tp, &len, &diff_iovecs);
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/*
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* Now (re-)position everything modified at the tail of the CIL.
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* We do this here so we only need to take the CIL lock once during
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* the transaction commit.
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*/
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spin_lock(&cil->xc_cil_lock);
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list_for_each_entry(lidp, &tp->t_items, lid_trans) {
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struct xfs_log_item *lip = lidp->lid_item;
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/* Skip items which aren't dirty in this transaction. */
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if (!(lidp->lid_flags & XFS_LID_DIRTY))
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continue;
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list_move_tail(&lip->li_cil, &cil->xc_cil);
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}
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/* account for space used by new iovec headers */
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len += diff_iovecs * sizeof(xlog_op_header_t);
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ctx->nvecs += diff_iovecs;
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/* attach the transaction to the CIL if it has any busy extents */
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if (!list_empty(&tp->t_busy))
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list_splice_init(&tp->t_busy, &ctx->busy_extents);
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/*
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* Now transfer enough transaction reservation to the context ticket
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* for the checkpoint. The context ticket is special - the unit
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* reservation has to grow as well as the current reservation as we
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* steal from tickets so we can correctly determine the space used
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* during the transaction commit.
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*/
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if (ctx->ticket->t_curr_res == 0) {
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ctx->ticket->t_curr_res = ctx->ticket->t_unit_res;
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tp->t_ticket->t_curr_res -= ctx->ticket->t_unit_res;
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}
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/* do we need space for more log record headers? */
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iclog_space = log->l_iclog_size - log->l_iclog_hsize;
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if (len > 0 && (ctx->space_used / iclog_space !=
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(ctx->space_used + len) / iclog_space)) {
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int hdrs;
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hdrs = (len + iclog_space - 1) / iclog_space;
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/* need to take into account split region headers, too */
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hdrs *= log->l_iclog_hsize + sizeof(struct xlog_op_header);
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ctx->ticket->t_unit_res += hdrs;
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ctx->ticket->t_curr_res += hdrs;
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tp->t_ticket->t_curr_res -= hdrs;
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ASSERT(tp->t_ticket->t_curr_res >= len);
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}
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tp->t_ticket->t_curr_res -= len;
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ctx->space_used += len;
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spin_unlock(&cil->xc_cil_lock);
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}
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static void
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xlog_cil_free_logvec(
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struct xfs_log_vec *log_vector)
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{
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struct xfs_log_vec *lv;
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for (lv = log_vector; lv; ) {
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struct xfs_log_vec *next = lv->lv_next;
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kmem_free(lv);
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lv = next;
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}
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}
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/*
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* Mark all items committed and clear busy extents. We free the log vector
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* chains in a separate pass so that we unpin the log items as quickly as
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* possible.
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*/
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static void
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xlog_cil_committed(
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void *args,
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int abort)
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{
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struct xfs_cil_ctx *ctx = args;
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struct xfs_mount *mp = ctx->cil->xc_log->l_mp;
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xfs_trans_committed_bulk(ctx->cil->xc_log->l_ailp, ctx->lv_chain,
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ctx->start_lsn, abort);
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xfs_extent_busy_sort(&ctx->busy_extents);
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xfs_extent_busy_clear(mp, &ctx->busy_extents,
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(mp->m_flags & XFS_MOUNT_DISCARD) && !abort);
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/*
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* If we are aborting the commit, wake up anyone waiting on the
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* committing list. If we don't, then a shutdown we can leave processes
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* waiting in xlog_cil_force_lsn() waiting on a sequence commit that
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* will never happen because we aborted it.
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*/
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spin_lock(&ctx->cil->xc_push_lock);
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if (abort)
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wake_up_all(&ctx->cil->xc_commit_wait);
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list_del(&ctx->committing);
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spin_unlock(&ctx->cil->xc_push_lock);
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xlog_cil_free_logvec(ctx->lv_chain);
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if (!list_empty(&ctx->busy_extents)) {
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ASSERT(mp->m_flags & XFS_MOUNT_DISCARD);
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xfs_discard_extents(mp, &ctx->busy_extents);
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xfs_extent_busy_clear(mp, &ctx->busy_extents, false);
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}
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kmem_free(ctx);
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}
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/*
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* Push the Committed Item List to the log. If @push_seq flag is zero, then it
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* is a background flush and so we can chose to ignore it. Otherwise, if the
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* current sequence is the same as @push_seq we need to do a flush. If
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* @push_seq is less than the current sequence, then it has already been
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* flushed and we don't need to do anything - the caller will wait for it to
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* complete if necessary.
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*
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* @push_seq is a value rather than a flag because that allows us to do an
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* unlocked check of the sequence number for a match. Hence we can allows log
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* forces to run racily and not issue pushes for the same sequence twice. If we
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* get a race between multiple pushes for the same sequence they will block on
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* the first one and then abort, hence avoiding needless pushes.
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*/
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STATIC int
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xlog_cil_push(
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struct xlog *log)
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{
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struct xfs_cil *cil = log->l_cilp;
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struct xfs_log_vec *lv;
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struct xfs_cil_ctx *ctx;
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struct xfs_cil_ctx *new_ctx;
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struct xlog_in_core *commit_iclog;
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struct xlog_ticket *tic;
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int num_iovecs;
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int error = 0;
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struct xfs_trans_header thdr;
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struct xfs_log_iovec lhdr;
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struct xfs_log_vec lvhdr = { NULL };
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xfs_lsn_t commit_lsn;
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xfs_lsn_t push_seq;
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if (!cil)
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return 0;
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new_ctx = kmem_zalloc(sizeof(*new_ctx), KM_SLEEP|KM_NOFS);
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new_ctx->ticket = xlog_cil_ticket_alloc(log);
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down_write(&cil->xc_ctx_lock);
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ctx = cil->xc_ctx;
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spin_lock(&cil->xc_push_lock);
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push_seq = cil->xc_push_seq;
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ASSERT(push_seq <= ctx->sequence);
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/*
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* Check if we've anything to push. If there is nothing, then we don't
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* move on to a new sequence number and so we have to be able to push
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* this sequence again later.
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*/
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if (list_empty(&cil->xc_cil)) {
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cil->xc_push_seq = 0;
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spin_unlock(&cil->xc_push_lock);
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goto out_skip;
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}
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/* check for a previously pushed seqeunce */
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if (push_seq < cil->xc_ctx->sequence) {
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spin_unlock(&cil->xc_push_lock);
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goto out_skip;
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}
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/*
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* We are now going to push this context, so add it to the committing
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* list before we do anything else. This ensures that anyone waiting on
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* this push can easily detect the difference between a "push in
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* progress" and "CIL is empty, nothing to do".
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|
*
|
|
* 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);
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
lv = NULL;
|
|
num_iovecs = 0;
|
|
while (!list_empty(&cil->xc_cil)) {
|
|
struct xfs_log_item *item;
|
|
|
|
item = list_first_entry(&cil->xc_cil,
|
|
struct xfs_log_item, li_cil);
|
|
list_del_init(&item->li_cil);
|
|
if (!ctx->lv_chain)
|
|
ctx->lv_chain = item->li_lv;
|
|
else
|
|
lv->lv_next = item->li_lv;
|
|
lv = item->li_lv;
|
|
item->li_lv = NULL;
|
|
num_iovecs += lv->lv_niovecs;
|
|
}
|
|
|
|
/*
|
|
* initialise the new context and attach it to the CIL. Then attach
|
|
* the current context to the CIL committing lsit so it can be found
|
|
* during log forces to extract the commit lsn of the sequence that
|
|
* needs to be forced.
|
|
*/
|
|
INIT_LIST_HEAD(&new_ctx->committing);
|
|
INIT_LIST_HEAD(&new_ctx->busy_extents);
|
|
new_ctx->sequence = ctx->sequence + 1;
|
|
new_ctx->cil = cil;
|
|
cil->xc_ctx = new_ctx;
|
|
|
|
/*
|
|
* The switch is now done, 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_lsn 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);
|
|
cil->xc_current_sequence = new_ctx->sequence;
|
|
spin_unlock(&cil->xc_push_lock);
|
|
up_write(&cil->xc_ctx_lock);
|
|
|
|
/*
|
|
* 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().
|
|
*
|
|
* The LSN we need to pass to the log items on transaction commit is
|
|
* the LSN reported by the first log vector write. If we use the commit
|
|
* record lsn then we can move the tail beyond the grant write head.
|
|
*/
|
|
tic = ctx->ticket;
|
|
thdr.th_magic = XFS_TRANS_HEADER_MAGIC;
|
|
thdr.th_type = XFS_TRANS_CHECKPOINT;
|
|
thdr.th_tid = tic->t_tid;
|
|
thdr.th_num_items = num_iovecs;
|
|
lhdr.i_addr = &thdr;
|
|
lhdr.i_len = sizeof(xfs_trans_header_t);
|
|
lhdr.i_type = XLOG_REG_TYPE_TRANSHDR;
|
|
tic->t_curr_res -= lhdr.i_len + sizeof(xlog_op_header_t);
|
|
|
|
lvhdr.lv_niovecs = 1;
|
|
lvhdr.lv_iovecp = &lhdr;
|
|
lvhdr.lv_next = ctx->lv_chain;
|
|
|
|
error = xlog_write(log, &lvhdr, tic, &ctx->start_lsn, NULL, 0);
|
|
if (error)
|
|
goto out_abort_free_ticket;
|
|
|
|
/*
|
|
* now that we've written the checkpoint into the log, strictly
|
|
* order the commit records so replay will get them in the right order.
|
|
*/
|
|
restart:
|
|
spin_lock(&cil->xc_push_lock);
|
|
list_for_each_entry(new_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_FORCED_SHUTDOWN(log)) {
|
|
spin_unlock(&cil->xc_push_lock);
|
|
goto out_abort_free_ticket;
|
|
}
|
|
|
|
/*
|
|
* Higher sequences will wait for this one so skip them.
|
|
* Don't wait for our own sequence, either.
|
|
*/
|
|
if (new_ctx->sequence >= ctx->sequence)
|
|
continue;
|
|
if (!new_ctx->commit_lsn) {
|
|
/*
|
|
* It is still being pushed! Wait for the push to
|
|
* complete, then start again from the beginning.
|
|
*/
|
|
xlog_wait(&cil->xc_commit_wait, &cil->xc_push_lock);
|
|
goto restart;
|
|
}
|
|
}
|
|
spin_unlock(&cil->xc_push_lock);
|
|
|
|
/* xfs_log_done always frees the ticket on error. */
|
|
commit_lsn = xfs_log_done(log->l_mp, tic, &commit_iclog, 0);
|
|
if (commit_lsn == -1)
|
|
goto out_abort;
|
|
|
|
/* attach all the transactions w/ busy extents to iclog */
|
|
ctx->log_cb.cb_func = xlog_cil_committed;
|
|
ctx->log_cb.cb_arg = ctx;
|
|
error = xfs_log_notify(log->l_mp, commit_iclog, &ctx->log_cb);
|
|
if (error)
|
|
goto out_abort;
|
|
|
|
/*
|
|
* 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);
|
|
ctx->commit_lsn = commit_lsn;
|
|
wake_up_all(&cil->xc_commit_wait);
|
|
spin_unlock(&cil->xc_push_lock);
|
|
|
|
/* release the hounds! */
|
|
return xfs_log_release_iclog(log->l_mp, commit_iclog);
|
|
|
|
out_skip:
|
|
up_write(&cil->xc_ctx_lock);
|
|
xfs_log_ticket_put(new_ctx->ticket);
|
|
kmem_free(new_ctx);
|
|
return 0;
|
|
|
|
out_abort_free_ticket:
|
|
xfs_log_ticket_put(tic);
|
|
out_abort:
|
|
xlog_cil_committed(ctx, XFS_LI_ABORTED);
|
|
return -EIO;
|
|
}
|
|
|
|
static void
|
|
xlog_cil_push_work(
|
|
struct work_struct *work)
|
|
{
|
|
struct xfs_cil *cil = container_of(work, struct xfs_cil,
|
|
xc_push_work);
|
|
xlog_cil_push(cil->xc_log);
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
struct xfs_cil *cil = log->l_cilp;
|
|
|
|
/*
|
|
* 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(!list_empty(&cil->xc_cil));
|
|
|
|
/*
|
|
* don't do a background push if we haven't used up all the
|
|
* space available yet.
|
|
*/
|
|
if (cil->xc_ctx->space_used < XLOG_CIL_SPACE_LIMIT(log))
|
|
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(log->l_mp->m_cil_workqueue, &cil->xc_push_work);
|
|
}
|
|
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. The caller is expected to do any
|
|
* waiting for push_seq to complete if it is required.
|
|
*/
|
|
static void
|
|
xlog_cil_push_now(
|
|
struct xlog *log,
|
|
xfs_lsn_t push_seq)
|
|
{
|
|
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 */
|
|
flush_work(&cil->xc_push_work);
|
|
|
|
/*
|
|
* If the CIL is empty or we've already pushed the sequence then
|
|
* there's no work we need to do.
|
|
*/
|
|
spin_lock(&cil->xc_push_lock);
|
|
if (list_empty(&cil->xc_cil) || push_seq <= cil->xc_push_seq) {
|
|
spin_unlock(&cil->xc_push_lock);
|
|
return;
|
|
}
|
|
|
|
cil->xc_push_seq = push_seq;
|
|
queue_work(log->l_mp->m_cil_workqueue, &cil->xc_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 (list_empty(&cil->xc_cil))
|
|
empty = true;
|
|
spin_unlock(&cil->xc_push_lock);
|
|
return empty;
|
|
}
|
|
|
|
/*
|
|
* 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
|
|
xfs_log_commit_cil(
|
|
struct xfs_mount *mp,
|
|
struct xfs_trans *tp,
|
|
xfs_lsn_t *commit_lsn,
|
|
int flags)
|
|
{
|
|
struct xlog *log = mp->m_log;
|
|
struct xfs_cil *cil = log->l_cilp;
|
|
int log_flags = 0;
|
|
|
|
if (flags & XFS_TRANS_RELEASE_LOG_RES)
|
|
log_flags = XFS_LOG_REL_PERM_RESERV;
|
|
|
|
/* lock out background commit */
|
|
down_read(&cil->xc_ctx_lock);
|
|
|
|
xlog_cil_insert_items(log, tp);
|
|
|
|
/* check we didn't blow the reservation */
|
|
if (tp->t_ticket->t_curr_res < 0)
|
|
xlog_print_tic_res(mp, tp->t_ticket);
|
|
|
|
tp->t_commit_lsn = cil->xc_ctx->sequence;
|
|
if (commit_lsn)
|
|
*commit_lsn = tp->t_commit_lsn;
|
|
|
|
xfs_log_done(mp, tp->t_ticket, NULL, log_flags);
|
|
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 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.
|
|
*/
|
|
xfs_trans_free_items(tp, tp->t_commit_lsn, 0);
|
|
|
|
xlog_cil_push_background(log);
|
|
|
|
up_read(&cil->xc_ctx_lock);
|
|
}
|
|
|
|
/*
|
|
* 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_lsn(
|
|
struct xlog *log,
|
|
xfs_lsn_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);
|
|
|
|
/*
|
|
* 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);
|
|
|
|
/*
|
|
* 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_FORCED_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.
|
|
*/
|
|
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 &&
|
|
!list_empty(&cil->xc_cil)) {
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* Check if the current log item was first committed in this sequence.
|
|
* We can't rely on just the log item being in the CIL, we have to check
|
|
* the recorded commit sequence number.
|
|
*
|
|
* Note: for this to be used in a non-racy manner, it has to be called with
|
|
* CIL flushing locked out. As a result, it should only be used during the
|
|
* transaction commit process when deciding what to format into the item.
|
|
*/
|
|
bool
|
|
xfs_log_item_in_current_chkpt(
|
|
struct xfs_log_item *lip)
|
|
{
|
|
struct xfs_cil_ctx *ctx;
|
|
|
|
if (list_empty(&lip->li_cil))
|
|
return false;
|
|
|
|
ctx = lip->li_mountp->m_log->l_cilp->xc_ctx;
|
|
|
|
/*
|
|
* li_seq is written on the first commit of a log item to record the
|
|
* first checkpoint it is written to. Hence if it is different to the
|
|
* current sequence, we're in a new checkpoint.
|
|
*/
|
|
if (XFS_LSN_CMP(lip->li_seq, ctx->sequence) != 0)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Perform initial CIL structure initialisation.
|
|
*/
|
|
int
|
|
xlog_cil_init(
|
|
struct xlog *log)
|
|
{
|
|
struct xfs_cil *cil;
|
|
struct xfs_cil_ctx *ctx;
|
|
|
|
cil = kmem_zalloc(sizeof(*cil), KM_SLEEP|KM_MAYFAIL);
|
|
if (!cil)
|
|
return -ENOMEM;
|
|
|
|
ctx = kmem_zalloc(sizeof(*ctx), KM_SLEEP|KM_MAYFAIL);
|
|
if (!ctx) {
|
|
kmem_free(cil);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
INIT_WORK(&cil->xc_push_work, xlog_cil_push_work);
|
|
INIT_LIST_HEAD(&cil->xc_cil);
|
|
INIT_LIST_HEAD(&cil->xc_committing);
|
|
spin_lock_init(&cil->xc_cil_lock);
|
|
spin_lock_init(&cil->xc_push_lock);
|
|
init_rwsem(&cil->xc_ctx_lock);
|
|
init_waitqueue_head(&cil->xc_commit_wait);
|
|
|
|
INIT_LIST_HEAD(&ctx->committing);
|
|
INIT_LIST_HEAD(&ctx->busy_extents);
|
|
ctx->sequence = 1;
|
|
ctx->cil = cil;
|
|
cil->xc_ctx = ctx;
|
|
cil->xc_current_sequence = ctx->sequence;
|
|
|
|
cil->xc_log = log;
|
|
log->l_cilp = cil;
|
|
return 0;
|
|
}
|
|
|
|
void
|
|
xlog_cil_destroy(
|
|
struct xlog *log)
|
|
{
|
|
if (log->l_cilp->xc_ctx) {
|
|
if (log->l_cilp->xc_ctx->ticket)
|
|
xfs_log_ticket_put(log->l_cilp->xc_ctx->ticket);
|
|
kmem_free(log->l_cilp->xc_ctx);
|
|
}
|
|
|
|
ASSERT(list_empty(&log->l_cilp->xc_cil));
|
|
kmem_free(log->l_cilp);
|
|
}
|
|
|