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fsnotify: use an explicit flag to indicate fsnotify_destroy_mark has been called

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Currently fsnotify check is mark->group is NULL to decide if
fsnotify_destroy_mark() has already been called or not.  With the upcoming
rcu work it is a heck of a lot easier to use an explicit flag than worry
about group being set to NULL.

Signed-off-by: Eric Paris <eparis@redhat.com>
This commit is contained in:
Eric Paris
2010-07-28 10:18:38 -04:00
parent a4c6e9961f
commit 700307a29a
4 changed files with 10 additions and 6 deletions
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2
fs/notify/inode_mark.c
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@@ -187,7 +187,7 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
struct hlist_node *node, *last = NULL; struct hlist_node *node, *last = NULL;
int ret = 0; int ret = 0;
mark->flags = FSNOTIFY_MARK_FLAG_INODE; mark->flags |= FSNOTIFY_MARK_FLAG_INODE;
assert_spin_locked(&mark->lock); assert_spin_locked(&mark->lock);
assert_spin_locked(&group->mark_lock); assert_spin_locked(&group->mark_lock);

11
fs/notify/mark.c
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@@ -121,12 +121,14 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark)
group = mark->group; group = mark->group;
/* if !group something else already marked this to die */ /* something else already called this function on this mark */
if (!group) { if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) {
spin_unlock(&mark->lock); spin_unlock(&mark->lock);
return; return;
} }
mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
/* 1 from caller and 1 for being on i_list/g_list */ /* 1 from caller and 1 for being on i_list/g_list */
BUG_ON(atomic_read(&mark->refcnt) < 2); BUG_ON(atomic_read(&mark->refcnt) < 2);
@@ -141,7 +143,6 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark)
BUG(); BUG();
list_del_init(&mark->g_list); list_del_init(&mark->g_list);
mark->group = NULL;
fsnotify_put_mark(mark); /* for i_list and g_list */ fsnotify_put_mark(mark); /* for i_list and g_list */
@@ -229,6 +230,8 @@ int fsnotify_add_mark(struct fsnotify_mark *mark,
spin_lock(&mark->lock); spin_lock(&mark->lock);
spin_lock(&group->mark_lock); spin_lock(&group->mark_lock);
mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE;
mark->group = group; mark->group = group;
list_add(&mark->g_list, &group->marks_list); list_add(&mark->g_list, &group->marks_list);
atomic_inc(&group->num_marks); atomic_inc(&group->num_marks);
@@ -258,7 +261,7 @@ int fsnotify_add_mark(struct fsnotify_mark *mark,
return ret; return ret;
err: err:
mark->group = NULL; mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
list_del_init(&mark->g_list); list_del_init(&mark->g_list);
atomic_dec(&group->num_marks); atomic_dec(&group->num_marks);
fsnotify_put_mark(mark); fsnotify_put_mark(mark);

2
fs/notify/vfsmount_mark.c
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@@ -145,7 +145,7 @@ int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
struct hlist_node *node, *last = NULL; struct hlist_node *node, *last = NULL;
int ret = 0; int ret = 0;
mark->flags = FSNOTIFY_MARK_FLAG_VFSMOUNT; mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
assert_spin_locked(&mark->lock); assert_spin_locked(&mark->lock);
assert_spin_locked(&group->mark_lock); assert_spin_locked(&group->mark_lock);

1
include/linux/fsnotify_backend.h
View File

@@ -300,6 +300,7 @@ struct fsnotify_mark {
#define FSNOTIFY_MARK_FLAG_VFSMOUNT 0x02 #define FSNOTIFY_MARK_FLAG_VFSMOUNT 0x02
#define FSNOTIFY_MARK_FLAG_OBJECT_PINNED 0x04 #define FSNOTIFY_MARK_FLAG_OBJECT_PINNED 0x04
#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x08 #define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x08
#define FSNOTIFY_MARK_FLAG_ALIVE 0x10
unsigned int flags; /* vfsmount or inode mark? */ unsigned int flags; /* vfsmount or inode mark? */
void (*free_mark)(struct fsnotify_mark *mark); /* called on final put+free */ void (*free_mark)(struct fsnotify_mark *mark); /* called on final put+free */
}; };