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Commit 9c3e9025 authored by Al Viro's avatar Al Viro
Browse files

cachefiles: vfs_mkdir() might succeed leaving dentry negative unhashed 



That can (and does, on some filesystems) happen - ->mkdir() (and thus
vfs_mkdir()) can legitimately leave its argument negative and just
unhash it, counting upon the lookup to pick the object we'd created
next time we try to look at that name.

Some vfs_mkdir() callers forget about that possibility...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 7b745a4e

fs/cachefiles/namei.c

+10 −0
Original line number Diff line number Diff line
@@ -572,6 +572,11 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent, 
			if (ret < 0)

				goto create_error;



			if (unlikely(d_unhashed(next))) {

				dput(next);

				inode_unlock(d_inode(dir));

				goto lookup_again;

			}

			ASSERT(d_backing_inode(next));



			_debug("mkdir -> %p{%p{ino=%lu}}",
@@ -764,6 +769,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, 
	/* search the current directory for the element name */

	inode_lock(d_inode(dir));



retry:

	start = jiffies;

	subdir = lookup_one_len(dirname, dir, strlen(dirname));

	cachefiles_hist(cachefiles_lookup_histogram, start);
@@ -793,6 +799,10 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, 
		if (ret < 0)

			goto mkdir_error;



		if (unlikely(d_unhashed(subdir))) {

			dput(subdir);

			goto retry;

		}

		ASSERT(d_backing_inode(subdir));



		_debug("mkdir -> %p{%p{ino=%lu}}",