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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-31 19:15:23 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-31 19:15:23 -0800
commitdc1efc3cfaf5e16870a9a7b1b903dcf6e3ef15e8 (patch)
treec020453fcfc517dee72526fffc8be13f101951c0
parent73da9e1a9f310a449eeb9bf5735a9cd475fef5e2 (diff)
parent61647823aa920e395afcce4b57c32afb51456cab (diff)
Merge branch 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull dcache updates from Al Viro: "Neil Brown's d_move()/d_path() race fix" * 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: VFS: close race between getcwd() and d_move()
-rw-r--r--fs/dcache.c23
1 files changed, 16 insertions, 7 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index c6d996ee2d61..d93872d425d6 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -466,9 +466,11 @@ static void dentry_lru_add(struct dentry *dentry)
* d_drop() is used mainly for stuff that wants to invalidate a dentry for some
* reason (NFS timeouts or autofs deletes).
*
- * __d_drop requires dentry->d_lock.
+ * __d_drop requires dentry->d_lock
+ * ___d_drop doesn't mark dentry as "unhashed"
+ * (dentry->d_hash.pprev will be LIST_POISON2, not NULL).
*/
-void __d_drop(struct dentry *dentry)
+static void ___d_drop(struct dentry *dentry)
{
if (!d_unhashed(dentry)) {
struct hlist_bl_head *b;
@@ -484,12 +486,17 @@ void __d_drop(struct dentry *dentry)
hlist_bl_lock(b);
__hlist_bl_del(&dentry->d_hash);
- dentry->d_hash.pprev = NULL;
hlist_bl_unlock(b);
/* After this call, in-progress rcu-walk path lookup will fail. */
write_seqcount_invalidate(&dentry->d_seq);
}
}
+
+void __d_drop(struct dentry *dentry)
+{
+ ___d_drop(dentry);
+ dentry->d_hash.pprev = NULL;
+}
EXPORT_SYMBOL(__d_drop);
void d_drop(struct dentry *dentry)
@@ -2380,7 +2387,7 @@ EXPORT_SYMBOL(d_delete);
static void __d_rehash(struct dentry *entry)
{
struct hlist_bl_head *b = d_hash(entry->d_name.hash);
- BUG_ON(!d_unhashed(entry));
+
hlist_bl_lock(b);
hlist_bl_add_head_rcu(&entry->d_hash, b);
hlist_bl_unlock(b);
@@ -2815,9 +2822,9 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED);
/* unhash both */
- /* __d_drop does write_seqcount_barrier, but they're OK to nest. */
- __d_drop(dentry);
- __d_drop(target);
+ /* ___d_drop does write_seqcount_barrier, but they're OK to nest. */
+ ___d_drop(dentry);
+ ___d_drop(target);
/* Switch the names.. */
if (exchange)
@@ -2829,6 +2836,8 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
__d_rehash(dentry);
if (exchange)
__d_rehash(target);
+ else
+ target->d_hash.pprev = NULL;
/* ... and switch them in the tree */
if (IS_ROOT(dentry)) {