Hi,
On Tue, 2007-07-24 at 08:24 -0500, Kevin Anderson wrote:
> What bugzilla does this address?
>
> Kevin
>
bz #248479, GFS2: cat /debug/gfs2/morph-cluster:gfs_vs0/glocks, panic!
Steve.
> On Tue, 2007-07-24 at 14:11 +0100, Steven Whitehouse wrote:
> > Hi,
> >
> > This fixes an oops which was occurring during glock dumping due to the
> > seq file code not taking a reference to the glock. Also this fixes a
> > memory leak which occurred in certain cases, in turn preventing the
> > filesystem from unmounting.
> >
> > Steve.
> >
> > ----------------------------------------------------------------------
> > diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
> > index d403fd7..e4bc8ae 100644
> > --- a/fs/gfs2/glock.c
> > +++ b/fs/gfs2/glock.c
> > @@ -46,7 +46,6 @@ struct glock_iter {
> > int hash; /* hash bucket index */
> > struct gfs2_sbd *sdp; /* incore superblock */
> > struct gfs2_glock *gl; /* current glock struct */
> > - struct hlist_head *hb_list; /* current hash bucket ptr */
> > struct seq_file *seq; /* sequence file for debugfs */
> > char string[512]; /* scratch space */
> > };
> > @@ -1990,47 +1989,38 @@ int __init gfs2_glock_init(void)
> >
> > static int gfs2_glock_iter_next(struct glock_iter *gi)
> > {
> > + struct gfs2_glock *gl;
> > +
> > read_lock(gl_lock_addr(gi->hash));
> > - while (1) {
> > - if (!gi->hb_list) { /* If we don't have a hash bucket yet */
> > - gi->hb_list = &gl_hash_table[gi->hash].hb_list;
> > - if (hlist_empty(gi->hb_list)) {
> > - read_unlock(gl_lock_addr(gi->hash));
> > - gi->hash++;
> > - read_lock(gl_lock_addr(gi->hash));
> > - gi->hb_list = NULL;
> > - if (gi->hash >= GFS2_GL_HASH_SIZE) {
> > - read_unlock(gl_lock_addr(gi->hash));
> > - return 1;
> > - }
> > - else
> > - continue;
> > - }
> > - if (!hlist_empty(gi->hb_list)) {
> > - gi->gl = list_entry(gi->hb_list->first,
> > - struct gfs2_glock,
> > - gl_list);
> > - }
> > - } else {
> > - if (gi->gl->gl_list.next == NULL) {
> > - read_unlock(gl_lock_addr(gi->hash));
> > - gi->hash++;
> > - read_lock(gl_lock_addr(gi->hash));
> > - gi->hb_list = NULL;
> > - continue;
> > - }
> > - gi->gl = list_entry(gi->gl->gl_list.next,
> > - struct gfs2_glock, gl_list);
> > - }
> > + gl = gi->gl;
> > + if (gl) {
> > + gi->gl = hlist_entry(gl->gl_list.next, struct gfs2_glock,
> > + gl_list);
> > if (gi->gl)
> > - break;
> > + gfs2_glock_hold(gi->gl);
> > }
> > read_unlock(gl_lock_addr(gi->hash));
> > + if (gl)
> > + gfs2_glock_put(gl);
> > +
> > + while(gi->gl == NULL) {
> > + gi->hash++;
> > + if (gi->hash >= GFS2_GL_HASH_SIZE)
> > + return 1;
> > + read_lock(gl_lock_addr(gi->hash));
> > + gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first,
> > + struct gfs2_glock, gl_list);
> > + if (gi->gl)
> > + gfs2_glock_hold(gi->gl);
> > + read_unlock(gl_lock_addr(gi->hash));
> > + }
> > return 0;
> > }
> >
> > static void gfs2_glock_iter_free(struct glock_iter *gi)
> > {
> > + if (gi->gl)
> > + gfs2_glock_put(gi->gl);
> > kfree(gi);
> > }
> >
> > @@ -2044,12 +2034,17 @@ static struct glock_iter
> > *gfs2_glock_iter_init(struct gfs2_sbd *sdp)
> >
> > gi->sdp = sdp;
> > gi->hash = 0;
> > - gi->gl = NULL;
> > - gi->hb_list = NULL;
> > gi->seq = NULL;
> > memset(gi->string, 0, sizeof(gi->string));
> >
> > - if (gfs2_glock_iter_next(gi)) {
> > + read_lock(gl_lock_addr(gi->hash));
> > + gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first,
> > + struct gfs2_glock, gl_list);
> > + if (gi->gl)
> > + gfs2_glock_hold(gi->gl);
> > + read_unlock(gl_lock_addr(gi->hash));
> > +
> > + if (!gi->gl && gfs2_glock_iter_next(gi)) {
> > gfs2_glock_iter_free(gi);
> > return NULL;
> > }
> > @@ -2066,7 +2061,7 @@ static void *gfs2_glock_seq_start(struct seq_file
> > *file, loff_t *pos)
> > if (!gi)
> > return NULL;
> >
> > - while (n--) {
> > + while(n--) {
> > if (gfs2_glock_iter_next(gi)) {
> > gfs2_glock_iter_free(gi);
> > return NULL;
> > @@ -2093,7 +2088,9 @@ static void *gfs2_glock_seq_next(struct seq_file
> > *file, void *iter_ptr,
> >
> > static void gfs2_glock_seq_stop(struct seq_file *file, void *iter_ptr)
> > {
> > - /* nothing for now */
> > + struct glock_iter *gi = iter_ptr;
> > + if (gi)
> > + gfs2_glock_iter_free(gi);
> > }
> >
> > static int gfs2_glock_seq_show(struct seq_file *file, void *iter_ptr)
> >
> >
