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Commit 5153bc81 authored by David Howells's avatar David Howells Committed by Al Viro
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VFS: Cachefiles should perform fs modifications on the top layer only 



Cachefiles should perform fs modifications (eg. vfs_unlink()) on the top layer
only and should not attempt to alter the lower layer.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ee8ac4d6

fs/cachefiles/interface.c

+2 −2
Original line number Diff line number Diff line
@@ -446,7 +446,7 @@ static int cachefiles_attr_changed(struct fscache_object *_object) 
		return 0;



	cachefiles_begin_secure(cache, &saved_cred);

	mutex_lock(&object->backer->d_inode->i_mutex);

	mutex_lock(&d_inode(object->backer)->i_mutex);



	/* if there's an extension to a partial page at the end of the backing

	 * file, we need to discard the partial page so that we pick up new
@@ -465,7 +465,7 @@ static int cachefiles_attr_changed(struct fscache_object *_object) 
	ret = notify_change(object->backer, &newattrs, NULL);



truncate_failed:

	mutex_unlock(&object->backer->d_inode->i_mutex);

	mutex_unlock(&d_inode(object->backer)->i_mutex);

	cachefiles_end_secure(cache, saved_cred);



	if (ret == -EIO) {

fs/cachefiles/namei.c

+26 −26
Original line number Diff line number Diff line
@@ -286,13 +286,13 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache, 
		if (ret < 0) {

			cachefiles_io_error(cache, "Unlink security error");

		} else {

			ret = vfs_unlink(dir->d_inode, rep, NULL);

			ret = vfs_unlink(d_inode(dir), rep, NULL);



			if (preemptive)

				cachefiles_mark_object_buried(cache, rep);

		}



		mutex_unlock(&dir->d_inode->i_mutex);

		mutex_unlock(&d_inode(dir)->i_mutex);



		if (ret == -EIO)

			cachefiles_io_error(cache, "Unlink failed");
@@ -303,7 +303,7 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache, 


	/* directories have to be moved to the graveyard */

	_debug("move stale object to graveyard");

	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);



try_again:

	/* first step is to make up a grave dentry in the graveyard */
@@ -387,8 +387,8 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache, 
	if (ret < 0) {

		cachefiles_io_error(cache, "Rename security error %d", ret);

	} else {

		ret = vfs_rename(dir->d_inode, rep,

				 cache->graveyard->d_inode, grave, NULL, 0);

		ret = vfs_rename(d_inode(dir), rep,

				 d_inode(cache->graveyard), grave, NULL, 0);

		if (ret != 0 && ret != -ENOMEM)

			cachefiles_io_error(cache,

					    "Rename failed with error %d", ret);
@@ -420,13 +420,13 @@ int cachefiles_delete_object(struct cachefiles_cache *cache, 


	dir = dget_parent(object->dentry);



	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);

	mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);



	if (test_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) {

		/* object allocation for the same key preemptively deleted this

		 * object's file so that it could create its own file */

		_debug("object preemptively buried");

		mutex_unlock(&dir->d_inode->i_mutex);

		mutex_unlock(&d_inode(dir)->i_mutex);

		ret = 0;

	} else {

		/* we need to check that our parent is _still_ our parent - it
@@ -438,7 +438,7 @@ int cachefiles_delete_object(struct cachefiles_cache *cache, 
			/* it got moved, presumably by cachefilesd culling it,

			 * so it's no longer in the key path and we can ignore

			 * it */

			mutex_unlock(&dir->d_inode->i_mutex);

			mutex_unlock(&d_inode(dir)->i_mutex);

			ret = 0;

		}

	}
@@ -497,7 +497,7 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent, 
	/* search the current directory for the element name */

	_debug("lookup '%s'", name);



	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);

	mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);



	start = jiffies;

	next = lookup_one_len(name, dir, nlen);
@@ -529,7 +529,7 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent, 
			if (ret < 0)

				goto create_error;

			start = jiffies;

			ret = vfs_mkdir(dir->d_inode, next, 0);

			ret = vfs_mkdir(d_inode(dir), next, 0);

			cachefiles_hist(cachefiles_mkdir_histogram, start);

			if (ret < 0)

				goto create_error;
@@ -558,7 +558,7 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent, 
			if (ret < 0)

				goto create_error;

			start = jiffies;

			ret = vfs_create(dir->d_inode, next, S_IFREG, true);

			ret = vfs_create(d_inode(dir), next, S_IFREG, true);

			cachefiles_hist(cachefiles_create_histogram, start);

			if (ret < 0)

				goto create_error;
@@ -581,7 +581,7 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent, 
	/* process the next component */

	if (key) {

		_debug("advance");

		mutex_unlock(&dir->d_inode->i_mutex);

		mutex_unlock(&d_inode(dir)->i_mutex);

		dput(dir);

		dir = next;

		next = NULL;
@@ -617,7 +617,7 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent, 
	/* note that we're now using this object */

	ret = cachefiles_mark_object_active(cache, object);



	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);

	dput(dir);

	dir = NULL;
@@ -695,7 +695,7 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent, 
		cachefiles_io_error(cache, "Lookup failed");

	next = NULL;

error:

	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);

	dput(next);

error_out2:

	dput(dir);
@@ -719,7 +719,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, 
	_enter(",,%s", dirname);



	/* search the current directory for the element name */

	mutex_lock(&dir->d_inode->i_mutex);

	mutex_lock(&d_inode(dir)->i_mutex);



	start = jiffies;

	subdir = lookup_one_len(dirname, dir, strlen(dirname));
@@ -746,7 +746,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, 
		ret = security_path_mkdir(&path, subdir, 0700);

		if (ret < 0)

			goto mkdir_error;

		ret = vfs_mkdir(dir->d_inode, subdir, 0700);

		ret = vfs_mkdir(d_inode(dir), subdir, 0700);

		if (ret < 0)

			goto mkdir_error;
@@ -758,7 +758,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, 
		       subdir->d_inode->i_ino);

	}



	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);



	/* we need to make sure the subdir is a directory */

	ASSERT(subdir->d_inode);
@@ -790,19 +790,19 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, 
	return ERR_PTR(ret);



mkdir_error:

	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);

	dput(subdir);

	pr_err("mkdir %s failed with error %d\n", dirname, ret);

	return ERR_PTR(ret);



lookup_error:

	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);

	ret = PTR_ERR(subdir);

	pr_err("Lookup %s failed with error %d\n", dirname, ret);

	return ERR_PTR(ret);



nomem_d_alloc:

	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);

	_leave(" = -ENOMEM");

	return ERR_PTR(-ENOMEM);

}
@@ -827,7 +827,7 @@ static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, 
	//       dir, filename);



	/* look up the victim */

	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);

	mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);



	start = jiffies;

	victim = lookup_one_len(filename, dir, strlen(filename));
@@ -842,7 +842,7 @@ static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, 
	 * at the netfs's request whilst the cull was in progress

	 */

	if (!victim->d_inode) {

		mutex_unlock(&dir->d_inode->i_mutex);

		mutex_unlock(&d_inode(dir)->i_mutex);

		dput(victim);

		_leave(" = -ENOENT [absent]");

		return ERR_PTR(-ENOENT);
@@ -871,13 +871,13 @@ static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, 


object_in_use:

	read_unlock(&cache->active_lock);

	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);

	dput(victim);

	//_leave(" = -EBUSY [in use]");

	return ERR_PTR(-EBUSY);



lookup_error:

	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);

	ret = PTR_ERR(victim);

	if (ret == -ENOENT) {

		/* file or dir now absent - probably retired by netfs */
@@ -936,7 +936,7 @@ int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, 
	return 0;



error_unlock:

	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);

error:

	dput(victim);

	if (ret == -ENOENT) {
@@ -971,7 +971,7 @@ int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, 
	if (IS_ERR(victim))

		return PTR_ERR(victim);



	mutex_unlock(&dir->d_inode->i_mutex);

	mutex_unlock(&d_inode(dir)->i_mutex);

	dput(victim);

	//_leave(" = 0");

	return 0;