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authorBenjamin Marzinski <bmarzins@redhat.com>2013-07-26 17:09:33 -0500
committerSteven Whitehouse <swhiteho@redhat.com>2013-08-19 09:33:16 +0100
commit1bc333f4cf601f77ba0f5046ff226fe654e83bee (patch)
treef9afd95be5ff9cfeb41050b078cb0bc78aec425d
parentd08fa65a81625765ff4733b4a6556b7156954073 (diff)
downloadlinux-1bc333f4cf601f77ba0f5046ff226fe654e83bee.tar.gz
GFS2: don't overrun reserved revokes
When run during fsync, a gfs2_log_flush could happen between the time when gfs2_ail_flush checked the number of blocks to revoke, and when it actually started the transaction to do those revokes. This occassionally caused it to need more revokes than it reserved, causing gfs2 to crash. Instead of just reserving enough revokes to handle the blocks that currently need them, this patch makes gfs2_ail_flush reserve the maximum number of revokes it can, without increasing the total number of reserved log blocks. This patch also passes the number of reserved revokes to __gfs2_ail_flush() so that it doesn't go over its limit and cause a crash like we're seeing. Non-fsync calls to __gfs2_ail_flush will still cause a BUG() necessary revokes are skipped. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
-rw-r--r--fs/gfs2/glops.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 5f2e5224c51c..e2e0a90396e7 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -47,7 +47,8 @@ static void gfs2_ail_error(struct gfs2_glock *gl, const struct buffer_head *bh)
* None of the buffers should be dirty, locked, or pinned.
*/
-static void __gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
+static void __gfs2_ail_flush(struct gfs2_glock *gl, bool fsync,
+ unsigned int nr_revokes)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct list_head *head = &gl->gl_ail_list;
@@ -57,7 +58,9 @@ static void __gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
gfs2_log_lock(sdp);
spin_lock(&sdp->sd_ail_lock);
- list_for_each_entry_safe(bd, tmp, head, bd_ail_gl_list) {
+ list_for_each_entry_safe_reverse(bd, tmp, head, bd_ail_gl_list) {
+ if (nr_revokes == 0)
+ break;
bh = bd->bd_bh;
if (bh->b_state & b_state) {
if (fsync)
@@ -65,6 +68,7 @@ static void __gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
gfs2_ail_error(gl, bh);
}
gfs2_trans_add_revoke(sdp, bd);
+ nr_revokes--;
}
GLOCK_BUG_ON(gl, !fsync && atomic_read(&gl->gl_ail_count));
spin_unlock(&sdp->sd_ail_lock);
@@ -91,7 +95,7 @@ static void gfs2_ail_empty_gl(struct gfs2_glock *gl)
WARN_ON_ONCE(current->journal_info);
current->journal_info = &tr;
- __gfs2_ail_flush(gl, 0);
+ __gfs2_ail_flush(gl, 0, tr.tr_revokes);
gfs2_trans_end(sdp);
gfs2_log_flush(sdp, NULL);
@@ -101,15 +105,19 @@ void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
unsigned int revokes = atomic_read(&gl->gl_ail_count);
+ unsigned int max_revokes = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) / sizeof(u64);
int ret;
if (!revokes)
return;
- ret = gfs2_trans_begin(sdp, 0, revokes);
+ while (revokes > max_revokes)
+ max_revokes += (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header)) / sizeof(u64);
+
+ ret = gfs2_trans_begin(sdp, 0, max_revokes);
if (ret)
return;
- __gfs2_ail_flush(gl, fsync);
+ __gfs2_ail_flush(gl, fsync, max_revokes);
gfs2_trans_end(sdp);
gfs2_log_flush(sdp, NULL);
}