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Commit dc1efc3c authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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()
parents 73da9e1a 61647823

fs/dcache.c

+16 −7
Original line number Diff line number Diff line
@@ -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)) {