On Tue, Jun 12 2007, Jens Axboe wrote:
> On Tue, Jun 12 2007, Krzysztof Lichota wrote:
> > Jens Axboe napisa??(a):
> > >> Should I investigate it further or is it a known issue?
> > >
> > > I think it's a known issue. Don't run blktrace -k unless the trace is
> > > really stuck - does it work correctly if you just ctrl-c out of
> > > blktrace?
> >
> > Yes, it works. I just got the impression that blktrace -k is the
> > preferred way of terminating the trace.
>
> oh no, -k is for KILL, extremely unpolite :-)
>
> > Thanks for help :)
>
> It sounds like you have found a way to reliably cause that bug, so I'll
> see if I can reproduce and get it fixed.
This should fix it, no more stuck traces.
diff --git a/block/blktrace.c b/block/blktrace.c
index 3f0e7c3..0ad5a77 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -180,53 +180,11 @@ EXPORT_SYMBOL_GPL(__blk_add_trace);
static struct dentry *blk_tree_root;
static struct mutex blk_tree_mutex;
-static unsigned int root_users;
-
-static inline void blk_remove_root(void)
-{
- if (blk_tree_root) {
- debugfs_remove(blk_tree_root);
- blk_tree_root = NULL;
- }
-}
-
-static void blk_remove_tree(struct dentry *dir)
-{
- mutex_lock(&blk_tree_mutex);
- debugfs_remove(dir);
- if (--root_users == 0)
- blk_remove_root();
- mutex_unlock(&blk_tree_mutex);
-}
-
-static struct dentry *blk_create_tree(const char *blk_name)
-{
- struct dentry *dir = NULL;
-
- mutex_lock(&blk_tree_mutex);
-
- if (!blk_tree_root) {
- blk_tree_root = debugfs_create_dir("block", NULL);
- if (!blk_tree_root)
- goto err;
- }
-
- dir = debugfs_create_dir(blk_name, blk_tree_root);
- if (dir)
- root_users++;
- else
- blk_remove_root();
-
-err:
- mutex_unlock(&blk_tree_mutex);
- return dir;
-}
static void blk_trace_cleanup(struct blk_trace *bt)
{
- relay_close(bt->rchan);
debugfs_remove(bt->dropped_file);
- blk_remove_tree(bt->dir);
+ relay_close(bt->rchan);
free_percpu(bt->sequence);
kfree(bt);
}
@@ -289,7 +247,18 @@ static int blk_subbuf_start_callback(struct rchan_buf
*buf, void *subbuf,
static int blk_remove_buf_file_callback(struct dentry *dentry)
{
+ struct dentry *parent = dentry->d_parent;
+
debugfs_remove(dentry);
+
+ /*
+ * this will fail for all but the last file, but that is ok. what we
+ * care about is the top level buts.name directory going away, when
+ * the last trace file is gone. Then we don't have to rmdir() that
+ * manually on trace stop, so it nicely solves the issue with
+ * force killing of running traces.
+ */
+ debugfs_remove(parent);
return 0;
}
@@ -350,7 +319,7 @@ static int blk_trace_setup(request_queue_t *q, struct
block_device *bdev,
goto err;
ret = -ENOENT;
- dir = blk_create_tree(buts.name);
+ dir = debugfs_create_dir(buts.name, blk_tree_root);
if (!dir)
goto err;
@@ -388,8 +357,6 @@ static int blk_trace_setup(request_queue_t *q, struct
block_device *bdev,
return 0;
err:
- if (dir)
- blk_remove_tree(dir);
if (bt) {
if (bt->dropped_file)
debugfs_remove(bt->dropped_file);
@@ -555,8 +522,11 @@ static __init int blk_trace_init(void)
on_each_cpu(blk_trace_check_cpu_time, NULL, 1, 1);
blk_trace_set_ht_offsets();
+ blk_tree_root = debugfs_create_dir("block", NULL);
+ if (!blk_tree_root)
+ return -ENOMEM;
+
return 0;
}
module_init(blk_trace_init);
-
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index ec8896b..8f3c999 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -345,11 +345,6 @@ void debugfs_remove(struct dentry *dentry)
switch (dentry->d_inode->i_mode & S_IFMT) {
case S_IFDIR:
ret = simple_rmdir(parent->d_inode, dentry);
- if (ret)
- printk(KERN_ERR
- "DebugFS rmdir on %s failed : "
- "directory not empty.\n",
- dentry->d_name.name);
break;
case S_IFLNK:
kfree(dentry->d_inode->i_private);
--
Jens Axboe
-
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