[PATCH 05/51] [GFS2] Fix an oops in glock dumping

swhiteho
2007-10-04T09:18:39Z

From: Steven Whitehouse <swhiteho@redhat.com>

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.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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)
--
1.5.1.2