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authorSteven Whitehouse <swhiteho@redhat.com>2008-09-26 10:23:22 +0100
committerSteven Whitehouse <swhiteho@redhat.com>2008-09-26 10:23:22 +0100
commit254db57f9b12daba841a4d91ddb9a8161e9c74ba (patch)
treee5d4f107d8bdf6278738c85a67b54d96d1a900e8
parent6d80c39f9155e289fe8037a8b6352931ff916ceb (diff)
downloadop-kernel-dev-254db57f9b12daba841a4d91ddb9a8161e9c74ba.zip
op-kernel-dev-254db57f9b12daba841a4d91ddb9a8161e9c74ba.tar.gz
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 <swhiteho@redhat.com>
-rw-r--r--fs/gfs2/incore.h1
-rw-r--r--fs/gfs2/log.c21
2 files changed, 19 insertions, 3 deletions
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index f1ed3a1..f566ec1 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 6c6af9f..ad30585 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -18,6 +18,7 @@
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
+#include <linux/bio.h>
#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);
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