diff options
| author | Lino Sanfilippo <LinoSanfilippo@gmx.de> | 2011-06-14 17:29:48 +0200 |
|---|---|---|
| committer | Eric Paris <eparis@redhat.com> | 2012-12-11 13:29:45 -0500 |
| commit | 104d06f08ea59247cb0e7e548c5a5d22d21dcfd5 (patch) | |
| tree | 91f380d7fd26cbcab88635327c99524e9164d36f /fs | |
| parent | 23e964c284ca0a767b80a30482bd53b059d30391 (diff) | |
fsnotify: take groups mark_lock before mark lock
Race-free addition and removal of a mark to a groups mark list would be easier
if we could lock the mark list of group before we lock the specific mark.
This patch changes the order used to add/remove marks to/from mark lists from
1. mark->lock
2. group->mark_lock
3. inode->i_lock
to
1. group->mark_lock
2. mark->lock
3. inode->i_lock
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/notify/mark.c | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/fs/notify/mark.c b/fs/notify/mark.c index 3c7a1699df3..32447dc06c0 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -127,20 +127,27 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark) struct inode *inode = NULL; spin_lock(&mark->lock); - + /* dont get the group from a mark that is not alive yet */ + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) { + spin_unlock(&mark->lock); + return; + } fsnotify_get_group(mark->group); group = mark->group; + spin_unlock(&mark->lock); + + spin_lock(&group->mark_lock); + spin_lock(&mark->lock); /* something else already called this function on this mark */ if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) { spin_unlock(&mark->lock); + spin_unlock(&group->mark_lock); goto put_group; } mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; - spin_lock(&group->mark_lock); - if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) { inode = mark->i.inode; fsnotify_destroy_inode_mark(mark); @@ -151,8 +158,8 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark) list_del_init(&mark->g_list); - spin_unlock(&group->mark_lock); spin_unlock(&mark->lock); + spin_unlock(&group->mark_lock); spin_lock(&destroy_lock); list_add(&mark->destroy_list, &destroy_list); @@ -225,13 +232,13 @@ int fsnotify_add_mark(struct fsnotify_mark *mark, /* * LOCKING ORDER!!!! - * mark->lock * group->mark_lock + * mark->lock * inode->i_lock */ - spin_lock(&mark->lock); spin_lock(&group->mark_lock); + spin_lock(&mark->lock); mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE; fsnotify_get_group(group); @@ -252,13 +259,12 @@ int fsnotify_add_mark(struct fsnotify_mark *mark, BUG(); } - spin_unlock(&group->mark_lock); - /* this will pin the object if appropriate */ fsnotify_set_mark_mask_locked(mark, mark->mask); - spin_unlock(&mark->lock); + spin_unlock(&group->mark_lock); + if (inode) __fsnotify_update_child_dentry_flags(inode); @@ -270,8 +276,8 @@ err: mark->group = NULL; atomic_dec(&group->num_marks); - spin_unlock(&group->mark_lock); spin_unlock(&mark->lock); + spin_unlock(&group->mark_lock); spin_lock(&destroy_lock); list_add(&mark->destroy_list, &destroy_list); |