From 5693384805ab2a3d474efccb968e32f9e2edbaf7 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 28 Jun 2019 19:27:22 -0700 Subject: [PATCH] xfs: factor out splitting of an iclog from xlog_sync Split out a self-contained chunk of code from xlog_sync that calculates the split offset for an iclog that wraps the log end and bumps the cycles for the second half. Use the chance to bring some sanity to the variables used to track the split in xlog_sync by not changing the count variable, and instead use split as the offset for the split and use those to calculate the sizes and offsets for the two write buffers. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_log.c | 63 +++++++++++++++++++++++++++++--------------------------- 1 file changed, 33 insertions(+), 30 deletions(-) diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 979a688..150c65c 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -1766,6 +1766,32 @@ xlog_write_iclog( } /* + * We need to bump cycle number for the part of the iclog that is + * written to the start of the log. Watch out for the header magic + * number case, though. + */ +static unsigned int +xlog_split_iclog( + struct xlog *log, + void *data, + uint64_t bno, + unsigned int count) +{ + unsigned int split_offset = BBTOB(log->l_logBBsize - bno); + unsigned int i; + + for (i = split_offset; i < count; i += BBSIZE) { + uint32_t cycle = get_unaligned_be32(data + i); + + if (++cycle == XLOG_HEADER_MAGIC_NUM) + cycle++; + put_unaligned_be32(cycle, data + i); + } + + return split_offset; +} + +/* * Flush out the in-core log (iclog) to the on-disk log in an asynchronous * fashion. Previously, we should have moved the current iclog * ptr in the log to point to the next available iclog. This allows further @@ -1793,13 +1819,12 @@ xlog_sync( struct xlog *log, struct xlog_in_core *iclog) { - int i; uint count; /* byte count of bwrite */ uint count_init; /* initial count before roundup */ int roundoff; /* roundoff to BB or stripe */ - int split = 0; /* split write into two regions */ int v2 = xfs_sb_version_haslogv2(&log->l_mp->m_sb); uint64_t bno; + unsigned int split = 0; int size; bool need_flush = true; @@ -1842,32 +1867,8 @@ xlog_sync( bno = BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn)); /* Do we need to split this write into 2 parts? */ - if (bno + BTOBB(count) > log->l_logBBsize) { - char *dptr; - - split = count - (BBTOB(log->l_logBBsize - bno)); - count = BBTOB(log->l_logBBsize - bno); - iclog->ic_bwritecnt = 2; - - /* - * Bump the cycle numbers at the start of each block in the - * part of the iclog that ends up in the buffer that gets - * written to the start of the log. - * - * Watch out for the header magic number case, though. - */ - dptr = (char *)&iclog->ic_header + count; - for (i = 0; i < split; i += BBSIZE) { - uint32_t cycle = be32_to_cpu(*(__be32 *)dptr); - if (++cycle == XLOG_HEADER_MAGIC_NUM) - cycle++; - *(__be32 *)dptr = cpu_to_be32(cycle); - - dptr += BBSIZE; - } - } else { - iclog->ic_bwritecnt = 1; - } + if (bno + BTOBB(count) > log->l_logBBsize) + split = xlog_split_iclog(log, &iclog->ic_header, bno, count); /* calculcate the checksum */ iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header, @@ -1902,14 +1903,16 @@ xlog_sync( need_flush = false; } - iclog->ic_bp->b_io_length = BTOBB(count); + iclog->ic_bp->b_io_length = BTOBB(split ? split : count); + iclog->ic_bwritecnt = split ? 2 : 1; xlog_verify_iclog(log, iclog, count, true); xlog_write_iclog(log, iclog, iclog->ic_bp, bno, need_flush); if (split) { xfs_buf_associate_memory(iclog->ic_log->l_xbuf, - (char *)&iclog->ic_header + count, split); + (char *)&iclog->ic_header + split, + count - split); xlog_write_iclog(log, iclog, iclog->ic_log->l_xbuf, 0, false); } } -- 2.7.4