[PATCH] [GFS2] Small fixes to logging code

From: swhiteho
Date: Mon Jul 09 2007 - 12:42:50 EST


From: Steven Whitehouse <swhiteho@xxxxxxxxxx>

This reverts part of an earlier patch which tried to reclaim
gfs2_bufdata structures too early and resulted in a "use after free"
case (this bit from me). Also a change to not write out log headers
unless we really need to (in the case of flushing nothing we don't need
a header) from Bob.

Signed-off-by: Steven Whitehouse <swhiteho@xxxxxxxxxx>
Signed-off-by: Bob Peterson <rpeterso@xxxxxxxxxx>

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 8fcfb78..f49a12e 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -237,10 +237,7 @@ static void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
list_del(&bd->bd_ail_st_list);
list_del(&bd->bd_ail_gl_list);
atomic_dec(&bd->bd_gl->gl_ail_count);
- if (bd->bd_bh)
- brelse(bd->bd_bh);
- else
- kmem_cache_free(gfs2_bufdata_cachep, bd);
+ brelse(bd->bd_bh);
}
}

@@ -583,6 +580,7 @@ static void log_flush_commit(struct gfs2_sbd *sdp)
struct list_head *head = &sdp->sd_log_flush_list;
struct gfs2_log_buf *lb;
struct buffer_head *bh;
+ int flushcount = 0;

while (!list_empty(head)) {
lb = list_entry(head->next, struct gfs2_log_buf, lb_list);
@@ -599,9 +597,20 @@ static void log_flush_commit(struct gfs2_sbd *sdp)
} else
brelse(bh);
kfree(lb);
+ flushcount++;
}

- log_write_header(sdp, 0, 0);
+ /* If nothing was journaled, the header is unplanned and unwanted. */
+ if (flushcount) {
+ log_write_header(sdp, 0, 0);
+ } else {
+ unsigned int tail;
+ tail = current_tail(sdp);
+
+ gfs2_ail1_empty(sdp, 0);
+ if (sdp->sd_log_tail != tail)
+ log_pull_tail(sdp, tail);
+ }
}

/**
--
1.5.1.2

-
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