[PATCH 1/4] kill-the-bkl/reiserfs: fix "reiserfs lock" / "inode mutex" lock inversion dependency

From: Frederic Weisbecker
Date: Mon Aug 24 2009 - 22:33:49 EST


reiserfs_xattr_init is called with the reiserfs write lock held, but
if the ".reiserfs_priv" entry is not created, we take the superblock
root directory inode mutex until .reiserfs_priv is created.

This creates a lock dependency inversion against other sites such as
reiserfs_file_release() which takes an inode mutex and the reiserfs
lock after.

Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jeff Mahoney <jeffm@xxxxxxxx>
Cc: Chris Mason <chris.mason@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Alexander Beregalov <a.beregalov@xxxxxxxxx>
Cc: Laurent Riffard <laurent.riffard@xxxxxxx>
---
fs/reiserfs/xattr.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 59870a4..58aa8e7 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -1004,7 +1004,7 @@ int reiserfs_xattr_init(struct super_block *s, int mount_flags)
goto error;

if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) {
- mutex_lock(&s->s_root->d_inode->i_mutex);
+ reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s);
err = create_privroot(REISERFS_SB(s)->priv_root);
mutex_unlock(&s->s_root->d_inode->i_mutex);
}
--
1.6.2.3

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