Commit 35fc51e7 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Jens Axboe

blktrace: Make sure BLKTRACETEARDOWN does the full cleanup.

if blktrace program segfault it will not be able
to call BLKTRACETEARDOWN. Now if we run the blktrace
again that would result in a failure to create the
block/<device> debugfs directory.This will result
in blk_remove_root() to be called which will set
blk_tree_root to NULL. But the  debugfs block dir
still exist because it contain subdirectory.

Now if we try to fix it using BLKTRACETEARDOWN
it won't work because blk_tree_root is NULL.

Fix the same.

Tested as below

root@qemu-image:/home/kvaneesh/blktrace# ./blktrace  -d /dev/hdc
Segmentation fault
root@qemu-image:/home/kvaneesh/blktrace# ./blktrace  -d /dev/hdc
BLKTRACESETUP: No such file or directory
Failed to start trace on /dev/hdc
root@qemu-image:/home/kvaneesh/blktrace# ./blktrace  -k /dev/hdc
root@qemu-image:/home/kvaneesh/blktrace# ./blktrace  -d /dev/hdc
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 8c27eba5
...@@ -202,6 +202,7 @@ static void blk_remove_tree(struct dentry *dir) ...@@ -202,6 +202,7 @@ static void blk_remove_tree(struct dentry *dir)
static struct dentry *blk_create_tree(const char *blk_name) static struct dentry *blk_create_tree(const char *blk_name)
{ {
struct dentry *dir = NULL; struct dentry *dir = NULL;
int created = 0;
mutex_lock(&blk_tree_mutex); mutex_lock(&blk_tree_mutex);
...@@ -209,13 +210,17 @@ static struct dentry *blk_create_tree(const char *blk_name) ...@@ -209,13 +210,17 @@ static struct dentry *blk_create_tree(const char *blk_name)
blk_tree_root = debugfs_create_dir("block", NULL); blk_tree_root = debugfs_create_dir("block", NULL);
if (!blk_tree_root) if (!blk_tree_root)
goto err; goto err;
created = 1;
} }
dir = debugfs_create_dir(blk_name, blk_tree_root); dir = debugfs_create_dir(blk_name, blk_tree_root);
if (dir) if (dir)
root_users++; root_users++;
else else {
blk_remove_root(); /* Delete root only if we created it */
if (created)
blk_remove_root();
}
err: err:
mutex_unlock(&blk_tree_mutex); mutex_unlock(&blk_tree_mutex);
......
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