From 254db57f9b12daba841a4d91ddb9a8161e9c74ba Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Fri, 26 Sep 2008 10:23:22 +0100 Subject: [PATCH] GFS2: Support for I/O barriers This patch adds barrier support to GFS2. There is not a lot of change really... we just add the barrier flag when we write journal header blocks. If the underlying device refuses to support them, we fall back to the previous way of doing things (wait for the I/O and hope) since there is nothing else we can do. There is no user configuration, barriers will always be on unless the device refuses to support them. This seems a reasonable solution to me since this is a correctness issue. Signed-off-by: Steven Whitehouse --- fs/gfs2/incore.h | 1 + fs/gfs2/log.c | 21 ++++++++++++++++++--- 2 files changed, 19 insertions(+), 3 deletions(-) diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h index f1ed3a1bf8a..f566ec1b4e8 100644 --- a/fs/gfs2/incore.h +++ b/fs/gfs2/incore.h @@ -432,6 +432,7 @@ enum { SDF_JOURNAL_CHECKED = 0, SDF_JOURNAL_LIVE = 1, SDF_SHUTDOWN = 2, + SDF_NOBARRIERS = 3, }; #define GFS2_FSNAME_LEN 256 diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 6c6af9f5e3a..ad305854bdc 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -18,6 +18,7 @@ #include #include #include +#include #include "gfs2.h" #include "incore.h" @@ -584,7 +585,6 @@ static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull) memset(bh->b_data, 0, bh->b_size); set_buffer_uptodate(bh); clear_buffer_dirty(bh); - unlock_buffer(bh); gfs2_ail1_empty(sdp, 0); tail = current_tail(sdp); @@ -601,8 +601,23 @@ static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull) hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header)); lh->lh_hash = cpu_to_be32(hash); - set_buffer_dirty(bh); - if (sync_dirty_buffer(bh)) + bh->b_end_io = end_buffer_write_sync; + if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) + goto skip_barrier; + get_bh(bh); + submit_bh(WRITE_BARRIER | (1 << BIO_RW_META), bh); + wait_on_buffer(bh); + if (buffer_eopnotsupp(bh)) { + clear_buffer_eopnotsupp(bh); + set_buffer_uptodate(bh); + set_bit(SDF_NOBARRIERS, &sdp->sd_flags); + lock_buffer(bh); +skip_barrier: + get_bh(bh); + submit_bh(WRITE_SYNC | (1 << BIO_RW_META), bh); + wait_on_buffer(bh); + } + if (!buffer_uptodate(bh)) gfs2_io_error_bh(sdp, bh); brelse(bh); -- 2.41.1