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authorFrederic Weisbecker <fweisbec@gmail.com>2009-05-16 20:12:08 +0400
committerFrederic Weisbecker <fweisbec@gmail.com>2009-09-14 09:18:24 +0400
commitc72e05756b900b3be24cd73a16de52bab80984c0 (patch)
tree4fc35ad9efc1a6a9ca14baa3612e551fb4da793e /fs/reiserfs/xattr.c
parent2ac626955ed62ee8596f00581f959cc86e6198d1 (diff)
downloadlinux-c72e05756b900b3be24cd73a16de52bab80984c0.tar.xz
kill-the-bkl/reiserfs: acquire the inode mutex safely
While searching a pathname, an inode mutex can be acquired in do_lookup() which calls reiserfs_lookup() which in turn acquires the write lock. On the other side reiserfs_fill_super() can acquire the write_lock and then call reiserfs_lookup_privroot() which can acquire an inode mutex (the root of the mount point). So we theoretically risk an AB - BA lock inversion that could lead to a deadlock. As for other lock dependencies found since the bkl to mutex conversion, the fix is to use reiserfs_mutex_lock_safe() which drops the lock dependency to the write lock. [ Impact: fix a possible deadlock with reiserfs ] Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alexander Beregalov <a.beregalov@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'fs/reiserfs/xattr.c')
-rw-r--r--fs/reiserfs/xattr.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 6925b835a43b..59870a4751cc 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -975,7 +975,7 @@ int reiserfs_lookup_privroot(struct super_block *s)
int err = 0;
/* If we don't have the privroot located yet - go find it */
- mutex_lock(&s->s_root->d_inode->i_mutex);
+ reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s);
dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
strlen(PRIVROOT_NAME));
if (!IS_ERR(dentry)) {
@@ -1011,7 +1011,7 @@ int reiserfs_xattr_init(struct super_block *s, int mount_flags)
if (privroot->d_inode) {
s->s_xattr = reiserfs_xattr_handlers;
- mutex_lock(&privroot->d_inode->i_mutex);
+ reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s);
if (!REISERFS_SB(s)->xattr_root) {
struct dentry *dentry;
dentry = lookup_one_len(XAROOT_NAME, privroot,