[Cluster-devel] [PATCH 2/3] gfs2: Stop using rhashtable_walk_peek
From: Andreas Gruenbacher
Function rhashtable_walk_peek is problematic because there is no
guarantee that the glock previously returned still exists; when that key
is deleted, rhashtable_walk_peek can end up returning a different key,
which will cause an inconsistent glock dump. Fix this by keeping track
of the current glock in the seq file iterator functions instead.
Signed-off-by: Andreas Gruenbacher
Signed-off-by: Bob Peterson
---
fs/gfs2/glock.c | 47 ---
1 file changed, 28 insertions(+), 19 deletions(-)
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 82fb5583445c..097bd3c0f270 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1923,28 +1923,37 @@ void gfs2_glock_exit(void)
static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
{
- if (n == 0)
- gi->gl = rhashtable_walk_peek(&gi->hti);
- else {
- gi->gl = rhashtable_walk_next(&gi->hti);
- n--;
+ struct gfs2_glock *gl = gi->gl;
+
+ if (gl) {
+ if (n == 0)
+ return;
+ if (!lockref_put_not_zero(&gl->gl_lockref))
+ gfs2_glock_queue_put(gl);
}
for (;;) {
- if (IS_ERR_OR_NULL(gi->gl)) {
- if (!gi->gl)
- return;
- if (PTR_ERR(gi->gl) != -EAGAIN) {
- gi->gl = NULL;
- return;
+ gl = rhashtable_walk_next(&gi->hti);
+ if (IS_ERR_OR_NULL(gl)) {
+ if (gl == ERR_PTR(-EAGAIN)) {
+ n = 1;
+ continue;
}
- n = 0;
- } else if (gi->sdp == gi->gl->gl_name.ln_sbd &&
- !__lockref_is_dead(&gi->gl->gl_lockref)) {
- if (!n--)
- break;
+ gl = NULL;
+ break;
+ }
+ if (gl->gl_name.ln_sbd != gi->sdp)
+ continue;
+ if (n <= 1) {
+ if (!lockref_get_not_dead(&gl->gl_lockref))
+ continue;
+ break;
+ } else {
+ if (__lockref_is_dead(&gl->gl_lockref))
+ continue;
+ n--;
}
- gi->gl = rhashtable_walk_next(&gi->hti);
}
+ gi->gl = gl;
}
static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
@@ -1988,7 +1997,6 @@ static void gfs2_glock_seq_stop(struct seq_file *seq,
void *iter_ptr)
{
struct gfs2_glock_iter *gi = seq->private;
- gi->gl = NULL;
rhashtable_walk_stop(&gi->hti);
}
@@ -2076,7 +2084,8 @@ static int gfs2_glocks_release(struct inode *inode,
struct file *file)
struct seq_file *seq = file->private_data;
struct gfs2_glock_iter *gi = seq->private;
- gi->gl = NULL;
+ if (gi->gl)
+ gfs2_glock_put(gi->gl);
rhashtable_walk_exit(&gi->hti);
return seq_release_private(inode, file);
}
--
2.14.3
[Cluster-devel] [PATCH 2/3] gfs2: Stop using rhashtable_walk_peek
From: Andreas Gruenbacher
Function rhashtable_walk_peek is problematic because there is no
guarantee that the glock previously returned still exists; when that key
is deleted, rhashtable_walk_peek can end up returning a different key,
which will cause an inconsistent glock dump. Fix this by keeping track
of the current glock in the seq file iterator functions instead.
Signed-off-by: Andreas Gruenbacher
Signed-off-by: Bob Peterson
---
fs/gfs2/glock.c | 47 ---
1 file changed, 28 insertions(+), 19 deletions(-)
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 82fb5583445c..097bd3c0f270 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1923,28 +1923,37 @@ void gfs2_glock_exit(void)
static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
{
- if (n == 0)
- gi->gl = rhashtable_walk_peek(&gi->hti);
- else {
- gi->gl = rhashtable_walk_next(&gi->hti);
- n--;
+ struct gfs2_glock *gl = gi->gl;
+
+ if (gl) {
+ if (n == 0)
+ return;
+ if (!lockref_put_not_zero(&gl->gl_lockref))
+ gfs2_glock_queue_put(gl);
}
for (;;) {
- if (IS_ERR_OR_NULL(gi->gl)) {
- if (!gi->gl)
- return;
- if (PTR_ERR(gi->gl) != -EAGAIN) {
- gi->gl = NULL;
- return;
+ gl = rhashtable_walk_next(&gi->hti);
+ if (IS_ERR_OR_NULL(gl)) {
+ if (gl == ERR_PTR(-EAGAIN)) {
+ n = 1;
+ continue;
}
- n = 0;
- } else if (gi->sdp == gi->gl->gl_name.ln_sbd &&
- !__lockref_is_dead(&gi->gl->gl_lockref)) {
- if (!n--)
- break;
+ gl = NULL;
+ break;
+ }
+ if (gl->gl_name.ln_sbd != gi->sdp)
+ continue;
+ if (n <= 1) {
+ if (!lockref_get_not_dead(&gl->gl_lockref))
+ continue;
+ break;
+ } else {
+ if (__lockref_is_dead(&gl->gl_lockref))
+ continue;
+ n--;
}
- gi->gl = rhashtable_walk_next(&gi->hti);
}
+ gi->gl = gl;
}
static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
@@ -1988,7 +1997,6 @@ static void gfs2_glock_seq_stop(struct seq_file *seq,
void *iter_ptr)
{
struct gfs2_glock_iter *gi = seq->private;
- gi->gl = NULL;
rhashtable_walk_stop(&gi->hti);
}
@@ -2076,7 +2084,8 @@ static int gfs2_glocks_release(struct inode *inode,
struct file *file)
struct seq_file *seq = file->private_data;
struct gfs2_glock_iter *gi = seq->private;
- gi->gl = NULL;
+ if (gi->gl)
+ gfs2_glock_put(gi->gl);
rhashtable_walk_exit(&gi->hti);
return seq_release_private(inode, file);
}
--
2.14.3
