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authorSteven Whitehouse <swhiteho@redhat.com>2009-02-05 10:12:38 +0000
committerSteven Whitehouse <steve@dolmen.chygwyn.com>2009-03-24 11:21:18 +0000
commitd8348de06f704fc34d24ec068546ecb1045fc11a (patch)
treee6b7eb01ec128e40b255b903e3c6629fbd8174e5 /fs/gfs2/glock.c
parente7c8707ea2b9106f0f78c43348ff5d5e82ba7961 (diff)
downloadconfigs-d8348de06f704fc34d24ec068546ecb1045fc11a.tar.gz
GFS2: Fix deadlock on journal flush
This patch fixes a deadlock when the journal is flushed and there are dirty inodes other than the one which caused the journal flush. Originally the journal flushing code was trying to obtain the transaction glock while running the flush code for an inode glock. We no longer require the transaction glock at this point in time since we know that any attempt to get the transaction glock from another node will result in a journal flush. So if we are flushing the journal, we can be sure that the transaction lock is still cached from when the transaction was started. By inlining a version of gfs2_trans_begin() (minus the bit which gets the transaction glock) we can avoid the deadlock problems caused if there is a demote request queued up on the transaction glock. In addition I've also moved the umount rwsem so that it covers the glock workqueue, since it all demotions are done by this workqueue now. That fixes a bug on umount which I came across while fixing the original problem. Reported-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs/gfs2/glock.c')
-rw-r--r--fs/gfs2/glock.c26
1 files changed, 12 insertions, 14 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 173e59ce9ad..ad8e121427c 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -167,6 +167,7 @@ static void glock_free(struct gfs2_glock *gl)
static void gfs2_glock_hold(struct gfs2_glock *gl)
{
+ GLOCK_BUG_ON(gl, atomic_read(&gl->gl_ref) == 0);
atomic_inc(&gl->gl_ref);
}
@@ -206,16 +207,15 @@ int gfs2_glock_put(struct gfs2_glock *gl)
atomic_dec(&lru_count);
}
spin_unlock(&lru_lock);
- GLOCK_BUG_ON(gl, !list_empty(&gl->gl_lru));
GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
glock_free(gl);
rv = 1;
goto out;
}
- write_unlock(gl_lock_addr(gl->gl_hash));
/* 1 for being hashed, 1 for having state != LM_ST_UNLOCKED */
if (atomic_read(&gl->gl_ref) == 2)
gfs2_glock_schedule_for_reclaim(gl);
+ write_unlock(gl_lock_addr(gl->gl_hash));
out:
return rv;
}
@@ -597,10 +597,11 @@ __acquires(&gl->gl_spin)
GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
+ down_read(&gfs2_umount_flush_sem);
if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
gl->gl_demote_state != gl->gl_state) {
if (find_first_holder(gl))
- goto out;
+ goto out_unlock;
if (nonblock)
goto out_sched;
set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
@@ -611,23 +612,26 @@ __acquires(&gl->gl_spin)
gfs2_demote_wake(gl);
ret = do_promote(gl);
if (ret == 0)
- goto out;
+ goto out_unlock;
if (ret == 2)
- return;
+ goto out_sem;
gh = find_first_waiter(gl);
gl->gl_target = gh->gh_state;
if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
do_error(gl, 0); /* Fail queued try locks */
}
do_xmote(gl, gh, gl->gl_target);
+out_sem:
+ up_read(&gfs2_umount_flush_sem);
return;
out_sched:
gfs2_glock_hold(gl);
if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
gfs2_glock_put(gl);
-out:
+out_unlock:
clear_bit(GLF_LOCK, &gl->gl_flags);
+ goto out_sem;
}
static void glock_work_func(struct work_struct *work)
@@ -1225,7 +1229,6 @@ void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
{
struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
- down_read(&gfs2_umount_flush_sem);
gl->gl_reply = ret;
if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_flags))) {
struct gfs2_holder *gh;
@@ -1236,16 +1239,13 @@ void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
((ret & ~LM_OUT_ST_MASK) != 0))
set_bit(GLF_FROZEN, &gl->gl_flags);
spin_unlock(&gl->gl_spin);
- if (test_bit(GLF_FROZEN, &gl->gl_flags)) {
- up_read(&gfs2_umount_flush_sem);
+ if (test_bit(GLF_FROZEN, &gl->gl_flags))
return;
- }
}
set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
gfs2_glock_hold(gl);
if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
gfs2_glock_put(gl);
- up_read(&gfs2_umount_flush_sem);
}
/**
@@ -1389,12 +1389,10 @@ static void thaw_glock(struct gfs2_glock *gl)
{
if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
return;
- down_read(&gfs2_umount_flush_sem);
set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
gfs2_glock_hold(gl);
if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
gfs2_glock_put(gl);
- up_read(&gfs2_umount_flush_sem);
}
/**
@@ -1580,7 +1578,7 @@ static const char *gflags2str(char *buf, const unsigned long *gflags)
if (test_bit(GLF_REPLY_PENDING, gflags))
*p++ = 'r';
if (test_bit(GLF_INITIAL, gflags))
- *p++ = 'i';
+ *p++ = 'I';
if (test_bit(GLF_FROZEN, gflags))
*p++ = 'F';
*p = 0;