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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2007-11-21 12:25:41 +0100
committerJens Axboe <jens.axboe@oracle.com>2007-11-27 09:19:39 +0100
commit35fc51e7a5056889421270c1fb63d8ec45fbccf4 (patch)
tree775462a1cc541b5442648343293f50263f5beb45 /block/blktrace.c
parent8c27eba54970c6ebbb408186e5baa2274435e869 (diff)
downloadop-kernel-dev-35fc51e7a5056889421270c1fb63d8ec45fbccf4.zip
op-kernel-dev-35fc51e7a5056889421270c1fb63d8ec45fbccf4.tar.gz
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: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blktrace.c')
-rw-r--r--block/blktrace.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/block/blktrace.c b/block/blktrace.c
index d00ac39..498a0a5 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);
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