xfs: introduce xlog_write_partial()
Re-implement writing of a log vector that does not fit into the current iclog. The iclog will already be in XLOG_STATE_WANT_SYNC because xlog_get_iclog_space() will have reserved all the remaining iclog space for us, hence we can simply iterate over the iovecs in the log vector getting more iclog space until the entire log vector is written. Handling this partial write case separately means we do need to pass unnecessary state around for the common, fast path case when the log vector fits entirely within the current iclog. It isolates the complexity and allows us to modify and improve the partial write case without impacting the simple fast path. This change includes several improvements incorporated from patches written by Christoph Hellwig. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Chandan Babu R <chandan.babu@oracle.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Dave Chinner
Dave Chinner
parent
db357078b0
commit
ad3e369318
432
fs/xfs/xfs_log.c
432
fs/xfs/xfs_log.c
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@ -2246,7 +2246,8 @@ xlog_write_full(
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{
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int index;
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ASSERT(*log_offset + *len <= iclog->ic_size);
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ASSERT(*log_offset + *len <= iclog->ic_size ||
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iclog->ic_state == XLOG_STATE_WANT_SYNC);
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/*
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* Ordered log vectors have no regions to write so this
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@ -2262,111 +2263,177 @@ xlog_write_full(
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}
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}
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static xlog_op_header_t *
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xlog_write_setup_ophdr(
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struct xlog_op_header *ophdr,
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struct xlog_ticket *ticket)
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static int
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xlog_write_get_more_iclog_space(
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struct xlog_ticket *ticket,
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struct xlog_in_core **iclogp,
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uint32_t *log_offset,
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uint32_t len,
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uint32_t *record_cnt,
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uint32_t *data_cnt,
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int *contwr)
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{
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ophdr->oh_clientid = XFS_TRANSACTION;
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ophdr->oh_res2 = 0;
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ophdr->oh_flags = 0;
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return ophdr;
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struct xlog_in_core *iclog = *iclogp;
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struct xlog *log = iclog->ic_log;
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int error;
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spin_lock(&log->l_icloglock);
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ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC);
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xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
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error = xlog_state_release_iclog(log, iclog);
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spin_unlock(&log->l_icloglock);
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if (error)
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return error;
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error = xlog_state_get_iclog_space(log, len, &iclog,
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ticket, contwr, log_offset);
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if (error)
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return error;
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*record_cnt = 0;
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*data_cnt = 0;
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*iclogp = iclog;
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return 0;
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}
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/*
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* Set up the parameters of the region copy into the log. This has
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* to handle region write split across multiple log buffers - this
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* state is kept external to this function so that this code can
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* be written in an obvious, self documenting manner.
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* Write log vectors into a single iclog which is smaller than the current chain
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* length. We write until we cannot fit a full record into the remaining space
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* and then stop. We return the log vector that is to be written that cannot
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* wholly fit in the iclog.
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*/
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static int
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xlog_write_setup_copy(
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xlog_write_partial(
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struct xfs_log_vec *lv,
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struct xlog_ticket *ticket,
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struct xlog_op_header *ophdr,
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int space_available,
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int space_required,
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int *copy_off,
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int *copy_len,
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int *last_was_partial_copy,
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int *bytes_consumed)
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{
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int still_to_copy;
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still_to_copy = space_required - *bytes_consumed;
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*copy_off = *bytes_consumed;
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if (still_to_copy <= space_available) {
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/* write of region completes here */
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*copy_len = still_to_copy;
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ophdr->oh_len = cpu_to_be32(*copy_len);
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if (*last_was_partial_copy)
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ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
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*last_was_partial_copy = 0;
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*bytes_consumed = 0;
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return 0;
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}
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/* partial write of region, needs extra log op header reservation */
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*copy_len = space_available;
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ophdr->oh_len = cpu_to_be32(*copy_len);
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ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
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if (*last_was_partial_copy)
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ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
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*bytes_consumed += *copy_len;
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(*last_was_partial_copy)++;
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/* account for new log op header */
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ticket->t_curr_res -= sizeof(struct xlog_op_header);
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return sizeof(struct xlog_op_header);
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}
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static int
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xlog_write_copy_finish(
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struct xlog *log,
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struct xlog_in_core *iclog,
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uint flags,
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int *record_cnt,
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int *data_cnt,
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int *partial_copy,
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int *partial_copy_len,
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int log_offset)
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struct xlog_in_core **iclogp,
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uint32_t *log_offset,
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uint32_t *len,
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uint32_t *record_cnt,
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uint32_t *data_cnt,
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int *contwr)
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{
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struct xlog_in_core *iclog = *iclogp;
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struct xlog *log = iclog->ic_log;
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struct xlog_op_header *ophdr;
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int index = 0;
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uint32_t rlen;
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int error;
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if (*partial_copy) {
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/* walk the logvec, copying until we run out of space in the iclog */
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for (index = 0; index < lv->lv_niovecs; index++) {
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struct xfs_log_iovec *reg = &lv->lv_iovecp[index];
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uint32_t reg_offset = 0;
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/*
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* This iclog has already been marked WANT_SYNC by
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* xlog_state_get_iclog_space.
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* The first region of a continuation must have a non-zero
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* length otherwise log recovery will just skip over it and
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* start recovering from the next opheader it finds. Because we
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* mark the next opheader as a continuation, recovery will then
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* incorrectly add the continuation to the previous region and
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* that breaks stuff.
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*
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* Hence if there isn't space for region data after the
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* opheader, then we need to start afresh with a new iclog.
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*/
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spin_lock(&log->l_icloglock);
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xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
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*record_cnt = 0;
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*data_cnt = 0;
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goto release_iclog;
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if (iclog->ic_size - *log_offset <=
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sizeof(struct xlog_op_header)) {
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error = xlog_write_get_more_iclog_space(ticket,
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&iclog, log_offset, *len, record_cnt,
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data_cnt, contwr);
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if (error)
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return error;
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}
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ophdr = reg->i_addr;
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rlen = min_t(uint32_t, reg->i_len, iclog->ic_size - *log_offset);
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ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
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ophdr->oh_len = cpu_to_be32(rlen - sizeof(struct xlog_op_header));
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if (rlen != reg->i_len)
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ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
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xlog_verify_dest_ptr(log, iclog->ic_datap + *log_offset);
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xlog_write_iovec(iclog, log_offset, reg->i_addr,
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rlen, len, record_cnt, data_cnt);
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/* If we wrote the whole region, move to the next. */
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if (rlen == reg->i_len)
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continue;
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/*
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* We now have a partially written iovec, but it can span
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* multiple iclogs so we loop here. First we release the iclog
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* we currently have, then we get a new iclog and add a new
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* opheader. Then we continue copying from where we were until
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* we either complete the iovec or fill the iclog. If we
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* complete the iovec, then we increment the index and go right
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* back to the top of the outer loop. if we fill the iclog, we
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* run the inner loop again.
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*
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* This is complicated by the tail of a region using all the
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* space in an iclog and hence requiring us to release the iclog
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* and get a new one before returning to the outer loop. We must
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* always guarantee that we exit this inner loop with at least
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* space for log transaction opheaders left in the current
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* iclog, hence we cannot just terminate the loop at the end
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* of the of the continuation. So we loop while there is no
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* space left in the current iclog, and check for the end of the
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* continuation after getting a new iclog.
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*/
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do {
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/*
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* Ensure we include the continuation opheader in the
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* space we need in the new iclog by adding that size
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* to the length we require. This continuation opheader
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* needs to be accounted to the ticket as the space it
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* consumes hasn't been accounted to the lv we are
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* writing.
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*/
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error = xlog_write_get_more_iclog_space(ticket,
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&iclog, log_offset,
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*len + sizeof(struct xlog_op_header),
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record_cnt, data_cnt, contwr);
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if (error)
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return error;
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ophdr = iclog->ic_datap + *log_offset;
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ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
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ophdr->oh_clientid = XFS_TRANSACTION;
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ophdr->oh_res2 = 0;
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ophdr->oh_flags = XLOG_WAS_CONT_TRANS;
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ticket->t_curr_res -= sizeof(struct xlog_op_header);
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*log_offset += sizeof(struct xlog_op_header);
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*data_cnt += sizeof(struct xlog_op_header);
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/*
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* If rlen fits in the iclog, then end the region
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* continuation. Otherwise we're going around again.
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*/
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reg_offset += rlen;
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rlen = reg->i_len - reg_offset;
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if (rlen <= iclog->ic_size - *log_offset)
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ophdr->oh_flags |= XLOG_END_TRANS;
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else
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ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
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rlen = min_t(uint32_t, rlen, iclog->ic_size - *log_offset);
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ophdr->oh_len = cpu_to_be32(rlen);
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xlog_verify_dest_ptr(log, iclog->ic_datap + *log_offset);
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xlog_write_iovec(iclog, log_offset,
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reg->i_addr + reg_offset,
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rlen, len, record_cnt, data_cnt);
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} while (ophdr->oh_flags & XLOG_CONTINUE_TRANS);
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}
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*partial_copy = 0;
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*partial_copy_len = 0;
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if (iclog->ic_size - log_offset > sizeof(xlog_op_header_t))
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return 0;
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/* no more space in this iclog - push it. */
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spin_lock(&log->l_icloglock);
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xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
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*record_cnt = 0;
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*data_cnt = 0;
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if (iclog->ic_state == XLOG_STATE_ACTIVE)
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xlog_state_switch_iclogs(log, iclog, 0);
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else
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ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC ||
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xlog_is_shutdown(log));
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release_iclog:
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error = xlog_state_release_iclog(log, iclog);
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spin_unlock(&log->l_icloglock);
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return error;
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/*
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* No more iovecs remain in this logvec so return the next log vec to
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* the caller so it can go back to fast path copying.
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*/
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*iclogp = iclog;
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return 0;
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}
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/*
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@ -2421,14 +2488,11 @@ xlog_write(
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{
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struct xlog_in_core *iclog = NULL;
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struct xfs_log_vec *lv = log_vector;
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struct xfs_log_iovec *vecp = lv->lv_iovecp;
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int index = 0;
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int partial_copy = 0;
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int partial_copy_len = 0;
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int contwr = 0;
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uint32_t record_cnt = 0;
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uint32_t data_cnt = 0;
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int error = 0;
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int log_offset;
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if (ticket->t_curr_res < 0) {
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xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
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@ -2437,151 +2501,54 @@ xlog_write(
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xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
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}
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while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
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void *ptr;
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int log_offset;
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error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
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&contwr, &log_offset);
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if (error)
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return error;
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error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
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&contwr, &log_offset);
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if (error)
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return error;
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ASSERT(log_offset <= iclog->ic_size - 1);
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ASSERT(log_offset <= iclog->ic_size - 1);
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/*
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* If we have a context pointer, pass it the first iclog we are
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* writing to so it can record state needed for iclog write
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* ordering.
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*/
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if (ctx)
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xlog_cil_set_ctx_write_state(ctx, iclog);
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while (lv) {
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/*
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* If we have a context pointer, pass it the first iclog we are
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* writing to so it can record state needed for iclog write
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* ordering.
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* If the entire log vec does not fit in the iclog, punt it to
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* the partial copy loop which can handle this case.
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*/
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if (ctx) {
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xlog_cil_set_ctx_write_state(ctx, iclog);
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ctx = NULL;
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}
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/* If this is a single iclog write, go fast... */
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if (!contwr && lv == log_vector) {
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while (lv) {
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xlog_write_full(lv, ticket, iclog, &log_offset,
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&len, &record_cnt, &data_cnt);
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lv = lv->lv_next;
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}
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data_cnt = 0;
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break;
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}
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/*
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* This loop writes out as many regions as can fit in the amount
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* of space which was allocated by xlog_state_get_iclog_space().
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*/
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ptr = iclog->ic_datap + log_offset;
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while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
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struct xfs_log_iovec *reg;
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struct xlog_op_header *ophdr;
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int copy_len;
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int copy_off;
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bool ordered = false;
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bool added_ophdr = false;
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/* ordered log vectors have no regions to write */
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if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) {
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ASSERT(lv->lv_niovecs == 0);
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ordered = true;
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goto next_lv;
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}
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reg = &vecp[index];
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ASSERT(reg->i_len % sizeof(int32_t) == 0);
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ASSERT((unsigned long)ptr % sizeof(int32_t) == 0);
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/*
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* Regions always have their ophdr at the start of the
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* region, except for:
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* - a transaction start which has a start record ophdr
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* before the first region ophdr; and
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* - the previous region didn't fully fit into an iclog
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* so needs a continuation ophdr to prepend the region
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* in this new iclog.
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*/
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ophdr = reg->i_addr;
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if (optype && index) {
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optype &= ~XLOG_START_TRANS;
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} else if (partial_copy) {
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ophdr = xlog_write_setup_ophdr(ptr, ticket);
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xlog_write_adv_cnt(&ptr, &len, &log_offset,
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sizeof(struct xlog_op_header));
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added_ophdr = true;
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}
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ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
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len += xlog_write_setup_copy(ticket, ophdr,
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iclog->ic_size-log_offset,
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reg->i_len,
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©_off, ©_len,
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&partial_copy,
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&partial_copy_len);
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xlog_verify_dest_ptr(log, ptr);
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/*
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* Wart: need to update length in embedded ophdr not
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* to include it's own length.
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*/
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if (!added_ophdr) {
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ophdr->oh_len = cpu_to_be32(copy_len -
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sizeof(struct xlog_op_header));
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}
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ASSERT(copy_len > 0);
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memcpy(ptr, reg->i_addr + copy_off, copy_len);
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xlog_write_adv_cnt(&ptr, &len, &log_offset, copy_len);
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if (added_ophdr)
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copy_len += sizeof(struct xlog_op_header);
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record_cnt++;
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data_cnt += contwr ? copy_len : 0;
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error = xlog_write_copy_finish(log, iclog, optype,
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&record_cnt, &data_cnt,
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&partial_copy,
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&partial_copy_len,
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log_offset);
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if (error)
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if (lv->lv_niovecs &&
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lv->lv_bytes > iclog->ic_size - log_offset) {
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error = xlog_write_partial(lv, ticket, &iclog,
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&log_offset, &len, &record_cnt,
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&data_cnt, &contwr);
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if (error) {
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/*
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* We have no iclog to release, so just return
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* the error immediately.
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*/
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return error;
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/*
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* if we had a partial copy, we need to get more iclog
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* space but we don't want to increment the region
|
||||
* index because there is still more is this region to
|
||||
* write.
|
||||
*
|
||||
* If we completed writing this region, and we flushed
|
||||
* the iclog (indicated by resetting of the record
|
||||
* count), then we also need to get more log space. If
|
||||
* this was the last record, though, we are done and
|
||||
* can just return.
|
||||
*/
|
||||
if (partial_copy)
|
||||
break;
|
||||
|
||||
if (++index == lv->lv_niovecs) {
|
||||
next_lv:
|
||||
lv = lv->lv_next;
|
||||
index = 0;
|
||||
if (lv)
|
||||
vecp = lv->lv_iovecp;
|
||||
}
|
||||
if (record_cnt == 0 && !ordered) {
|
||||
if (!lv)
|
||||
return 0;
|
||||
break;
|
||||
}
|
||||
} else {
|
||||
xlog_write_full(lv, ticket, iclog, &log_offset,
|
||||
&len, &record_cnt, &data_cnt);
|
||||
}
|
||||
lv = lv->lv_next;
|
||||
}
|
||||
|
||||
ASSERT(len == 0);
|
||||
|
||||
/*
|
||||
* We've already been guaranteed that the last writes will fit inside
|
||||
* the current iclog, and hence it will already have the space used by
|
||||
* those writes accounted to it. Hence we do not need to update the
|
||||
* iclog with the number of bytes written here.
|
||||
*/
|
||||
spin_lock(&log->l_icloglock);
|
||||
xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
|
||||
xlog_state_finish_copy(log, iclog, record_cnt, 0);
|
||||
error = xlog_state_release_iclog(log, iclog);
|
||||
spin_unlock(&log->l_icloglock);
|
||||
|
||||
|
|
@ -3738,11 +3705,12 @@ xlog_verify_iclog(
|
|||
iclog->ic_header.h_cycle_data[idx]);
|
||||
}
|
||||
}
|
||||
if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
|
||||
if (clientid != XFS_TRANSACTION && clientid != XFS_LOG) {
|
||||
xfs_warn(log->l_mp,
|
||||
"%s: invalid clientid %d op "PTR_FMT" offset 0x%lx",
|
||||
__func__, clientid, ophead,
|
||||
"%s: op %d invalid clientid %d op "PTR_FMT" offset 0x%lx",
|
||||
__func__, i, clientid, ophead,
|
||||
(unsigned long)field_offset);
|
||||
}
|
||||
|
||||
/* check length */
|
||||
p = &ophead->oh_len;
|
||||
|
|
|
|||
|
|
@ -491,14 +491,6 @@ extern struct kmem_cache *xfs_log_ticket_cache;
|
|||
struct xlog_ticket *xlog_ticket_alloc(struct xlog *log, int unit_bytes,
|
||||
int count, bool permanent);
|
||||
|
||||
static inline void
|
||||
xlog_write_adv_cnt(void **ptr, int *len, int *off, size_t bytes)
|
||||
{
|
||||
*ptr += bytes;
|
||||
*len -= bytes;
|
||||
*off += bytes;
|
||||
}
|
||||
|
||||
void xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket);
|
||||
void xlog_print_trans(struct xfs_trans *);
|
||||
int xlog_write(struct xlog *log, struct xfs_cil_ctx *ctx,
|
||||
|
|
|
|||
Loading…
Reference in New Issue