[GFS2] Don't do recursive locking in glock layer
This patch changes the last user of recursive locking so that it no longer needs this feature and removes it from the glock layer. This makes the glock code a lot simpler and easier to understand. Its also a prerequsite to adding support for the AOP_TRUNCATED_PAGE return code (or at least it is if you don't want your brain to melt in the process) I've left in a couple of checks just in case there is some place else in the code which is still using this feature that I didn't spot yet, but they can probably be removed long term. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This commit is contained in:
parent
3a2a9c96ac
commit
5965b1f479
162
fs/gfs2/glock.c
162
fs/gfs2/glock.c
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@ -449,86 +449,6 @@ void gfs2_holder_put(struct gfs2_holder *gh)
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kfree(gh);
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}
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/**
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* handle_recurse - put other holder structures (marked recursive)
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* into the holders list
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* @gh: the holder structure
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*
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*/
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static void handle_recurse(struct gfs2_holder *gh)
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{
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struct gfs2_glock *gl = gh->gh_gl;
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struct gfs2_sbd *sdp = gl->gl_sbd;
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struct gfs2_holder *tmp_gh, *safe;
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int found = 0;
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BUG_ON(!spin_is_locked(&gl->gl_spin));
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printk(KERN_INFO "recursion %016llx, %u\n", gl->gl_name.ln_number,
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gl->gl_name.ln_type);
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if (gfs2_assert_warn(sdp, gh->gh_owner))
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return;
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list_for_each_entry_safe(tmp_gh, safe, &gl->gl_waiters3, gh_list) {
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if (tmp_gh->gh_owner != gh->gh_owner)
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continue;
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gfs2_assert_warn(sdp,
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test_bit(HIF_RECURSE, &tmp_gh->gh_iflags));
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list_move_tail(&tmp_gh->gh_list, &gl->gl_holders);
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tmp_gh->gh_error = 0;
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set_bit(HIF_HOLDER, &tmp_gh->gh_iflags);
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complete(&tmp_gh->gh_wait);
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found = 1;
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}
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gfs2_assert_warn(sdp, found);
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}
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/**
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* do_unrecurse - a recursive holder was just dropped of the waiters3 list
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* @gh: the holder
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*
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* If there is only one other recursive holder, clear its HIF_RECURSE bit.
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* If there is more than one, leave them alone.
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*
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*/
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static void do_unrecurse(struct gfs2_holder *gh)
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{
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struct gfs2_glock *gl = gh->gh_gl;
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struct gfs2_sbd *sdp = gl->gl_sbd;
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struct gfs2_holder *tmp_gh, *last_gh = NULL;
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int found = 0;
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BUG_ON(!spin_is_locked(&gl->gl_spin));
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if (gfs2_assert_warn(sdp, gh->gh_owner))
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return;
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list_for_each_entry(tmp_gh, &gl->gl_waiters3, gh_list) {
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if (tmp_gh->gh_owner != gh->gh_owner)
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continue;
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gfs2_assert_warn(sdp,
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test_bit(HIF_RECURSE, &tmp_gh->gh_iflags));
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if (found)
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return;
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found = 1;
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last_gh = tmp_gh;
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}
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if (!gfs2_assert_warn(sdp, found))
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clear_bit(HIF_RECURSE, &last_gh->gh_iflags);
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}
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/**
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* rq_mutex - process a mutex request in the queue
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* @gh: the glock holder
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@ -562,7 +482,6 @@ static int rq_promote(struct gfs2_holder *gh)
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struct gfs2_glock *gl = gh->gh_gl;
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struct gfs2_sbd *sdp = gl->gl_sbd;
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struct gfs2_glock_operations *glops = gl->gl_ops;
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int recurse;
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if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
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if (list_empty(&gl->gl_holders)) {
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@ -588,7 +507,6 @@ static int rq_promote(struct gfs2_holder *gh)
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if (list_empty(&gl->gl_holders)) {
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set_bit(HIF_FIRST, &gh->gh_iflags);
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set_bit(GLF_LOCK, &gl->gl_flags);
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recurse = 0;
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} else {
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struct gfs2_holder *next_gh;
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if (gh->gh_flags & GL_LOCAL_EXCL)
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@ -597,16 +515,12 @@ static int rq_promote(struct gfs2_holder *gh)
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gh_list);
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if (next_gh->gh_flags & GL_LOCAL_EXCL)
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return 1;
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recurse = test_bit(HIF_RECURSE, &gh->gh_iflags);
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}
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list_move_tail(&gh->gh_list, &gl->gl_holders);
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gh->gh_error = 0;
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set_bit(HIF_HOLDER, &gh->gh_iflags);
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if (recurse)
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handle_recurse(gh);
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complete(&gh->gh_wait);
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return 0;
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@ -897,8 +811,6 @@ static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
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spin_lock(&gl->gl_spin);
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list_del_init(&gh->gh_list);
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gh->gh_error = -EIO;
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if (test_bit(HIF_RECURSE, &gh->gh_iflags))
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do_unrecurse(gh);
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spin_unlock(&gl->gl_spin);
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} else if (test_bit(HIF_DEMOTE, &gh->gh_iflags)) {
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@ -922,8 +834,6 @@ static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
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spin_lock(&gl->gl_spin);
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list_del_init(&gh->gh_list);
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gh->gh_error = GLR_CANCELED;
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if (test_bit(HIF_RECURSE, &gh->gh_iflags))
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do_unrecurse(gh);
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spin_unlock(&gl->gl_spin);
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} else if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
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@ -941,8 +851,6 @@ static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
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spin_lock(&gl->gl_spin);
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list_del_init(&gh->gh_list);
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gh->gh_error = GLR_TRYFAILED;
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if (test_bit(HIF_RECURSE, &gh->gh_iflags))
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do_unrecurse(gh);
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spin_unlock(&gl->gl_spin);
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} else {
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@ -1161,8 +1069,6 @@ static int glock_wait_internal(struct gfs2_holder *gh)
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!list_empty(&gh->gh_list)) {
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list_del_init(&gh->gh_list);
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gh->gh_error = GLR_TRYFAILED;
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if (test_bit(HIF_RECURSE, &gh->gh_iflags))
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do_unrecurse(gh);
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run_queue(gl);
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spin_unlock(&gl->gl_spin);
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return gh->gh_error;
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@ -1191,9 +1097,6 @@ static int glock_wait_internal(struct gfs2_holder *gh)
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if (gh->gh_error) {
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spin_lock(&gl->gl_spin);
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list_del_init(&gh->gh_list);
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if (test_and_clear_bit(HIF_RECURSE,
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&gh->gh_iflags))
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do_unrecurse(gh);
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spin_unlock(&gl->gl_spin);
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}
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}
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@ -1202,8 +1105,6 @@ static int glock_wait_internal(struct gfs2_holder *gh)
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gl->gl_req_gh = NULL;
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gl->gl_req_bh = NULL;
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clear_bit(GLF_LOCK, &gl->gl_flags);
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if (test_bit(HIF_RECURSE, &gh->gh_iflags))
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handle_recurse(gh);
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run_queue(gl);
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spin_unlock(&gl->gl_spin);
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}
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@ -1224,40 +1125,6 @@ find_holder_by_owner(struct list_head *head, struct task_struct *owner)
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return NULL;
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}
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/**
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* recurse_check -
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*
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* Make sure the new holder is compatible with the pre-existing one.
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*
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*/
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static int recurse_check(struct gfs2_holder *existing, struct gfs2_holder *new,
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unsigned int state)
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{
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struct gfs2_sbd *sdp = existing->gh_gl->gl_sbd;
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if (gfs2_assert_warn(sdp, (new->gh_flags & LM_FLAG_ANY) ||
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!(existing->gh_flags & LM_FLAG_ANY)))
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goto fail;
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if (gfs2_assert_warn(sdp, (existing->gh_flags & GL_LOCAL_EXCL) ||
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!(new->gh_flags & GL_LOCAL_EXCL)))
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goto fail;
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if (gfs2_assert_warn(sdp, relaxed_state_ok(state, new->gh_state,
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new->gh_flags)))
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goto fail;
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return 0;
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fail:
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print_symbol(KERN_WARNING "GFS2: Existing holder from %s\n",
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existing->gh_ip);
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print_symbol(KERN_WARNING "GFS2: New holder from %s\n", new->gh_ip);
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set_bit(HIF_ABORTED, &new->gh_iflags);
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return -EINVAL;
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}
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/**
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* add_to_queue - Add a holder to the wait queue (but look for recursion)
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* @gh: the holder structure to add
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BUG_ON(!gh->gh_owner);
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if (!gh->gh_owner)
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goto out;
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existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner);
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if (existing) {
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if (recurse_check(existing, gh, gl->gl_state))
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return;
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list_add_tail(&gh->gh_list, &gl->gl_holders);
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set_bit(HIF_HOLDER, &gh->gh_iflags);
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gh->gh_error = 0;
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complete(&gh->gh_wait);
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return;
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print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
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print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
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BUG();
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}
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existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner);
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if (existing) {
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if (recurse_check(existing, gh, existing->gh_state))
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return;
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set_bit(HIF_RECURSE, &gh->gh_iflags);
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set_bit(HIF_RECURSE, &existing->gh_iflags);
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list_add_tail(&gh->gh_list, &gl->gl_waiters3);
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return;
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print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
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print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
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BUG();
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}
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out:
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if (gh->gh_flags & LM_FLAG_PRIORITY)
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list_add(&gh->gh_list, &gl->gl_waiters3);
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else
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@ -146,7 +146,6 @@ enum {
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HIF_DEALLOC = 5,
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HIF_HOLDER = 6,
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HIF_FIRST = 7,
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HIF_RECURSE = 8,
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HIF_ABORTED = 9,
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};
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@ -436,30 +436,35 @@ int gfs2_recover_journal(struct gfs2_jdesc *jd)
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unsigned int pass;
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int error;
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fs_info(sdp, "jid=%u: Trying to acquire journal lock...\n", jd->jd_jid);
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if (jd->jd_jid != sdp->sd_lockstruct.ls_jid) {
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fs_info(sdp, "jid=%u: Trying to acquire journal lock...\n",
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jd->jd_jid);
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/* Aquire the journal lock so we can do recovery */
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/* Aquire the journal lock so we can do recovery */
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error = gfs2_glock_nq_num(sdp, jd->jd_jid, &gfs2_journal_glops,
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LM_ST_EXCLUSIVE,
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LM_FLAG_NOEXP | LM_FLAG_TRY | GL_NOCACHE,
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&j_gh);
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switch (error) {
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case 0:
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break;
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error = gfs2_glock_nq_num(sdp, jd->jd_jid, &gfs2_journal_glops,
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LM_ST_EXCLUSIVE,
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LM_FLAG_NOEXP | LM_FLAG_TRY | GL_NOCACHE,
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&j_gh);
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switch (error) {
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case 0:
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break;
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case GLR_TRYFAILED:
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fs_info(sdp, "jid=%u: Busy\n", jd->jd_jid);
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error = 0;
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default:
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goto fail;
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};
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case GLR_TRYFAILED:
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fs_info(sdp, "jid=%u: Busy\n", jd->jd_jid);
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error = 0;
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default:
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goto fail;
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};
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error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
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LM_FLAG_NOEXP, &ji_gh);
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if (error)
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goto fail_gunlock_j;
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error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
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LM_FLAG_NOEXP, &ji_gh);
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if (error)
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goto fail_gunlock_j;
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} else {
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fs_info(sdp, "jid=%u, already locked for use\n", jd->jd_jid);
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}
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fs_info(sdp, "jid=%u: Looking at journal...\n", jd->jd_jid);
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@ -481,10 +486,8 @@ int gfs2_recover_journal(struct gfs2_jdesc *jd)
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error = gfs2_glock_nq_init(sdp->sd_trans_gl,
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LM_ST_SHARED,
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LM_FLAG_NOEXP |
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LM_FLAG_PRIORITY |
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GL_NEVER_RECURSE |
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GL_NOCANCEL |
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LM_FLAG_NOEXP | LM_FLAG_PRIORITY |
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GL_NEVER_RECURSE | GL_NOCANCEL |
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GL_NOCACHE,
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&t_gh);
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if (error)
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goto fail_gunlock_tr;
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gfs2_glock_dq_uninit(&t_gh);
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t = DIV_ROUND_UP(jiffies - t, HZ);
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fs_info(sdp, "jid=%u: Journal replayed in %lus\n",
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jd->jd_jid, t);
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}
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gfs2_glock_dq_uninit(&ji_gh);
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if (jd->jd_jid != sdp->sd_lockstruct.ls_jid)
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gfs2_glock_dq_uninit(&ji_gh);
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gfs2_lm_recovery_done(sdp, jd->jd_jid, LM_RD_SUCCESS);
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gfs2_glock_dq_uninit(&j_gh);
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if (jd->jd_jid != sdp->sd_lockstruct.ls_jid)
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gfs2_glock_dq_uninit(&j_gh);
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fs_info(sdp, "jid=%u: Done\n", jd->jd_jid);
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return 0;
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fail_gunlock_tr:
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fail_gunlock_tr:
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gfs2_glock_dq_uninit(&t_gh);
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fail_gunlock_ji:
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gfs2_glock_dq_uninit(&ji_gh);
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fail_gunlock_j:
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gfs2_glock_dq_uninit(&j_gh);
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fail_gunlock_ji:
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if (jd->jd_jid != sdp->sd_lockstruct.ls_jid) {
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gfs2_glock_dq_uninit(&ji_gh);
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fail_gunlock_j:
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gfs2_glock_dq_uninit(&j_gh);
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}
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fs_info(sdp, "jid=%u: %s\n", jd->jd_jid, (error) ? "Failed" : "Done");
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fail:
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fail:
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gfs2_lm_recovery_done(sdp, jd->jd_jid, LM_RD_GAVEUP);
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return error;
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}
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