From 35fc51e7a5056889421270c1fb63d8ec45fbccf4 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Wed, 21 Nov 2007 12:25:41 +0100 Subject: [PATCH] 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/ 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: Aneesh Kumar K.V Signed-off-by: Jens Axboe --- block/blktrace.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/block/blktrace.c b/block/blktrace.c index d00ac3993c..498a0a54a6 100644 --- a/block/blktrace.c +++ b/block/blktrace.c @@ -202,6 +202,7 @@ static void blk_remove_tree(struct dentry *dir) static struct dentry *blk_create_tree(const char *blk_name) { struct dentry *dir = NULL; + int created = 0; mutex_lock(&blk_tree_mutex); @@ -209,13 +210,17 @@ static struct dentry *blk_create_tree(const char *blk_name) blk_tree_root = debugfs_create_dir("block", NULL); if (!blk_tree_root) goto err; + created = 1; } dir = debugfs_create_dir(blk_name, blk_tree_root); if (dir) root_users++; - else - blk_remove_root(); + else { + /* Delete root only if we created it */ + if (created) + blk_remove_root(); + } err: mutex_unlock(&blk_tree_mutex); -- 2.39.5