Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs fixes from Al Viro:
 "Assorted fixes, most in overlayfs land"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ovl: ovl_dir_fsync() cleanup
  ovl: update MAINTAINERS
  ovl: pass dentry into ovl_dir_read_merged()
  ovl: use lockless_dereference() for upperdentry
  ovl: allow filenames with comma
  ovl: fix race in private xattr checks
  ovl: fix remove/copy-up race
  ovl: rename filesystem type to "overlay"
  isofs: avoid unused function warning
  vfs: fix reference leak in d_prune_aliases()

11 files changed, 133 insertions, 85 deletions

diff --git a/Documentation/filesystems/overlayfs.txt b/Documentation/filesystems/overlayfs.txt
index 530850a..a27c950 100644
--- a/Documentation/filesystems/overlayfs.txt
+++ b/Documentation/filesystems/overlayfs.txt
@@ -64,7 +64,7 @@ is formed.
 At mount time, the two directories given as mount options "lowerdir" and
 "upperdir" are combined into a merged directory:
 
-  mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper,\
+  mount -t overlay overlay -olowerdir=/lower,upperdir=/upper,\
 workdir=/work /merged
 
 The "workdir" needs to be an empty directory on the same filesystem
diff --git a/MAINTAINERS b/MAINTAINERS
index c444907..0ff630d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6888,11 +6888,12 @@ F:	drivers/scsi/osd/
 F:	include/scsi/osd_*
 F:	fs/exofs/
 
-OVERLAYFS FILESYSTEM
+OVERLAY FILESYSTEM
 M:	Miklos Szeredi <miklos@szeredi.hu>
-L:	linux-fsdevel@vger.kernel.org
+L:	linux-unionfs@vger.kernel.org
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git
 S:	Supported
-F:	fs/overlayfs/*
+F:	fs/overlayfs/
 F:	Documentation/filesystems/overlayfs.txt
 
 P54 WIRELESS DRIVER
diff --git a/fs/Makefile b/fs/Makefile
index 34a1b9de..da0bbb4 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -104,7 +104,7 @@ obj-$(CONFIG_QNX6FS_FS)		+= qnx6/
 obj-$(CONFIG_AUTOFS4_FS)	+= autofs4/
 obj-$(CONFIG_ADFS_FS)		+= adfs/
 obj-$(CONFIG_FUSE_FS)		+= fuse/
-obj-$(CONFIG_OVERLAYFS_FS)	+= overlayfs/
+obj-$(CONFIG_OVERLAY_FS)	+= overlayfs/
 obj-$(CONFIG_UDF_FS)		+= udf/
 obj-$(CONFIG_SUN_OPENPROMFS)	+= openpromfs/
 obj-$(CONFIG_OMFS_FS)		+= omfs/
diff --git a/fs/dcache.c b/fs/dcache.c
index 3ffef7f..5bc72b0 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -778,6 +778,7 @@ restart:
 			struct dentry *parent = lock_parent(dentry);
 			if (likely(!dentry->d_lockref.count)) {
 				__dentry_kill(dentry);
+				dput(parent);
 				goto restart;
 			}
 			if (parent)
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index fe839b9..d67a16f 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -174,27 +174,6 @@ struct iso9660_options{
  * Compute the hash for the isofs name corresponding to the dentry.
  */
 static int
-isofs_hash_common(struct qstr *qstr, int ms)
-{
-	const char *name;
-	int len;
-
-	len = qstr->len;
-	name = qstr->name;
-	if (ms) {
-		while (len && name[len-1] == '.')
-			len--;
-	}
-
-	qstr->hash = full_name_hash(name, len);
-
-	return 0;
-}
-
-/*
- * Compute the hash for the isofs name corresponding to the dentry.
- */
-static int
 isofs_hashi_common(struct qstr *qstr, int ms)
 {
 	const char *name;
@@ -263,6 +242,27 @@ isofs_dentry_cmpi(const struct dentry *parent, const struct dentry *dentry,
 }
 
 #ifdef CONFIG_JOLIET
+/*
+ * Compute the hash for the isofs name corresponding to the dentry.
+ */
+static int
+isofs_hash_common(struct qstr *qstr, int ms)
+{
+	const char *name;
+	int len;
+
+	len = qstr->len;
+	name = qstr->name;
+	if (ms) {
+		while (len && name[len-1] == '.')
+			len--;
+	}
+
+	qstr->hash = full_name_hash(name, len);
+
+	return 0;
+}
+
 static int
 isofs_hash_ms(const struct dentry *dentry, struct qstr *qstr)
 {
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig
index e601259..3435581 100644
--- a/fs/overlayfs/Kconfig
+++ b/fs/overlayfs/Kconfig
@@ -1,4 +1,4 @@
-config OVERLAYFS_FS
+config OVERLAY_FS
 	tristate "Overlay filesystem support"
 	help
 	  An overlay filesystem combines two filesystems - an 'upper' filesystem
diff --git a/fs/overlayfs/Makefile b/fs/overlayfs/Makefile
index 8f91889..900daed 100644
--- a/fs/overlayfs/Makefile
+++ b/fs/overlayfs/Makefile
@@ -2,6 +2,6 @@
 # Makefile for the overlay filesystem.
 #
 
-obj-$(CONFIG_OVERLAYFS_FS) += overlayfs.o
+obj-$(CONFIG_OVERLAY_FS) += overlay.o
 
-overlayfs-objs := super.o inode.o dir.o readdir.o copy_up.o
+overlay-objs := super.o inode.o dir.o readdir.o copy_up.o
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 15cd91a..8ffc4b9 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -284,8 +284,7 @@ out:
 	return ERR_PTR(err);
 }
 
-static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry,
-						enum ovl_path_type type)
+static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
 {
 	int err;
 	struct dentry *ret = NULL;
@@ -294,8 +293,17 @@ static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry,
 	err = ovl_check_empty_dir(dentry, &list);
 	if (err)
 		ret = ERR_PTR(err);
-	else if (type == OVL_PATH_MERGE)
-		ret = ovl_clear_empty(dentry, &list);
+	else {
+		/*
+		 * If no upperdentry then skip clearing whiteouts.
+		 *
+		 * Can race with copy-up, since we don't hold the upperdir
+		 * mutex.  Doesn't matter, since copy-up can't create a
+		 * non-empty directory from an empty one.
+		 */
+		if (ovl_dentry_upper(dentry))
+			ret = ovl_clear_empty(dentry, &list);
+	}
 
 	ovl_cache_free(&list);
 
@@ -487,8 +495,7 @@ out:
 	return err;
 }
 
-static int ovl_remove_and_whiteout(struct dentry *dentry,
-				   enum ovl_path_type type, bool is_dir)
+static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
 {
 	struct dentry *workdir = ovl_workdir(dentry);
 	struct inode *wdir = workdir->d_inode;
@@ -500,7 +507,7 @@ static int ovl_remove_and_whiteout(struct dentry *dentry,
 	int err;
 
 	if (is_dir) {
-		opaquedir = ovl_check_empty_and_clear(dentry, type);
+		opaquedir = ovl_check_empty_and_clear(dentry);
 		err = PTR_ERR(opaquedir);
 		if (IS_ERR(opaquedir))
 			goto out;
@@ -515,9 +522,10 @@ static int ovl_remove_and_whiteout(struct dentry *dentry,
 	if (IS_ERR(whiteout))
 		goto out_unlock;
 
-	if (type == OVL_PATH_LOWER) {
+	upper = ovl_dentry_upper(dentry);
+	if (!upper) {
 		upper = lookup_one_len(dentry->d_name.name, upperdir,
-					   dentry->d_name.len);
+				       dentry->d_name.len);
 		err = PTR_ERR(upper);
 		if (IS_ERR(upper))
 			goto kill_whiteout;
@@ -529,7 +537,6 @@ static int ovl_remove_and_whiteout(struct dentry *dentry,
 	} else {
 		int flags = 0;
 
-		upper = ovl_dentry_upper(dentry);
 		if (opaquedir)
 			upper = opaquedir;
 		err = -ESTALE;
@@ -648,7 +655,7 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir)
 		cap_raise(override_cred->cap_effective, CAP_CHOWN);
 		old_cred = override_creds(override_cred);
 
-		err = ovl_remove_and_whiteout(dentry, type, is_dir);
+		err = ovl_remove_and_whiteout(dentry, is_dir);
 
 		revert_creds(old_cred);
 		put_cred(override_cred);
@@ -781,7 +788,7 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
 	}
 
 	if (overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir) {
-		opaquedir = ovl_check_empty_and_clear(new, new_type);
+		opaquedir = ovl_check_empty_and_clear(new);
 		err = PTR_ERR(opaquedir);
 		if (IS_ERR(opaquedir)) {
 			opaquedir = NULL;
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index af2d18c..07d74b2 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -235,26 +235,36 @@ out:
 	return err;
 }
 
+static bool ovl_need_xattr_filter(struct dentry *dentry,
+				  enum ovl_path_type type)
+{
+	return type == OVL_PATH_UPPER && S_ISDIR(dentry->d_inode->i_mode);
+}
+
 ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
 		     void *value, size_t size)
 {
-	if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
-	    ovl_is_private_xattr(name))
+	struct path realpath;
+	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
+
+	if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
 		return -ENODATA;
 
-	return vfs_getxattr(ovl_dentry_real(dentry), name, value, size);
+	return vfs_getxattr(realpath.dentry, name, value, size);
 }
 
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
 {
+	struct path realpath;
+	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
 	ssize_t res;
 	int off;
 
-	res = vfs_listxattr(ovl_dentry_real(dentry), list, size);
+	res = vfs_listxattr(realpath.dentry, list, size);
 	if (res <= 0 || size == 0)
 		return res;
 
-	if (ovl_path_type(dentry->d_parent) != OVL_PATH_MERGE)
+	if (!ovl_need_xattr_filter(dentry, type))
 		return res;
 
 	/* filter out private xattrs */
@@ -279,17 +289,16 @@ int ovl_removexattr(struct dentry *dentry, const char *name)
 {
 	int err;
 	struct path realpath;
-	enum ovl_path_type type;
+	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
 
 	err = ovl_want_write(dentry);
 	if (err)
 		goto out;
 
-	if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
-	    ovl_is_private_xattr(name))
+	err = -ENODATA;
+	if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
 		goto out_drop_write;
 
-	type = ovl_path_real(dentry, &realpath);
 	if (type == OVL_PATH_LOWER) {
 		err = vfs_getxattr(realpath.dentry, name, NULL, 0);
 		if (err < 0)
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 2a7ef4f..ab1e3dc 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -274,11 +274,11 @@ static int ovl_dir_mark_whiteouts(struct dentry *dir,
 	return 0;
 }
 
-static inline int ovl_dir_read_merged(struct path *upperpath,
-				      struct path *lowerpath,
-				      struct list_head *list)
+static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list)
 {
 	int err;
+	struct path lowerpath;
+	struct path upperpath;
 	struct ovl_readdir_data rdd = {
 		.ctx.actor = ovl_fill_merge,
 		.list = list,
@@ -286,25 +286,28 @@ static inline int ovl_dir_read_merged(struct path *upperpath,
 		.is_merge = false,
 	};
 
-	if (upperpath->dentry) {
-		err = ovl_dir_read(upperpath, &rdd);
+	ovl_path_lower(dentry, &lowerpath);
+	ovl_path_upper(dentry, &upperpath);
+
+	if (upperpath.dentry) {
+		err = ovl_dir_read(&upperpath, &rdd);
 		if (err)
 			goto out;
 
-		if (lowerpath->dentry) {
-			err = ovl_dir_mark_whiteouts(upperpath->dentry, &rdd);
+		if (lowerpath.dentry) {
+			err = ovl_dir_mark_whiteouts(upperpath.dentry, &rdd);
 			if (err)
 				goto out;
 		}
 	}
-	if (lowerpath->dentry) {
+	if (lowerpath.dentry) {
 		/*
 		 * Insert lowerpath entries before upperpath ones, this allows
 		 * offsets to be reasonably constant
 		 */
 		list_add(&rdd.middle, rdd.list);
 		rdd.is_merge = true;
-		err = ovl_dir_read(lowerpath, &rdd);
+		err = ovl_dir_read(&lowerpath, &rdd);
 		list_del(&rdd.middle);
 	}
 out:
@@ -329,8 +332,6 @@ static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos)
 static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry)
 {
 	int res;
-	struct path lowerpath;
-	struct path upperpath;
 	struct ovl_dir_cache *cache;
 
 	cache = ovl_dir_cache(dentry);
@@ -347,10 +348,7 @@ static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry)
 	cache->refcount = 1;
 	INIT_LIST_HEAD(&cache->entries);
 
-	ovl_path_lower(dentry, &lowerpath);
-	ovl_path_upper(dentry, &upperpath);
-
-	res = ovl_dir_read_merged(&upperpath, &lowerpath, &cache->entries);
+	res = ovl_dir_read_merged(dentry, &cache->entries);
 	if (res) {
 		ovl_cache_free(&cache->entries);
 		kfree(cache);
@@ -452,10 +450,10 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
 	/*
 	 * Need to check if we started out being a lower dir, but got copied up
 	 */
-	if (!od->is_upper && ovl_path_type(dentry) == OVL_PATH_MERGE) {
+	if (!od->is_upper && ovl_path_type(dentry) != OVL_PATH_LOWER) {
 		struct inode *inode = file_inode(file);
 
-		realfile =lockless_dereference(od->upperfile);
+		realfile = lockless_dereference(od->upperfile);
 		if (!realfile) {
 			struct path upperpath;
 
@@ -538,14 +536,9 @@ const struct file_operations ovl_dir_operations = {
 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)
 {
 	int err;
-	struct path lowerpath;
-	struct path upperpath;
 	struct ovl_cache_entry *p;
 
-	ovl_path_upper(dentry, &upperpath);
-	ovl_path_lower(dentry, &lowerpath);
-
-	err = ovl_dir_read_merged(&upperpath, &lowerpath, list);
+	err = ovl_dir_read_merged(dentry, list);
 	if (err)
 		return err;
 
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 08b704c..f16d318 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -24,7 +24,7 @@ MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
 MODULE_DESCRIPTION("Overlay filesystem");
 MODULE_LICENSE("GPL");
 
-#define OVERLAYFS_SUPER_MAGIC 0x794c764f
+#define OVERLAYFS_SUPER_MAGIC 0x794c7630
 
 struct ovl_config {
 	char *lowerdir;
@@ -84,12 +84,7 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry)
 
 static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
 {
-	struct dentry *upperdentry = ACCESS_ONCE(oe->__upperdentry);
-	/*
-	 * Make sure to order reads to upperdentry wrt ovl_dentry_update()
-	 */
-	smp_read_barrier_depends();
-	return upperdentry;
+	return lockless_dereference(oe->__upperdentry);
 }
 
 void ovl_path_upper(struct dentry *dentry, struct path *path)
@@ -462,11 +457,34 @@ static const match_table_t ovl_tokens = {
 	{OPT_ERR,			NULL}
 };
 
+static char *ovl_next_opt(char **s)
+{
+	char *sbegin = *s;
+	char *p;
+
+	if (sbegin == NULL)
+		return NULL;
+
+	for (p = sbegin; *p; p++) {
+		if (*p == '\\') {
+			p++;
+			if (!*p)
+				break;
+		} else if (*p == ',') {
+			*p = '\0';
+			*s = p + 1;
+			return sbegin;
+		}
+	}
+	*s = NULL;
+	return sbegin;
+}
+
 static int ovl_parse_opt(char *opt, struct ovl_config *config)
 {
 	char *p;
 
-	while ((p = strsep(&opt, ",")) != NULL) {
+	while ((p = ovl_next_opt(&opt)) != NULL) {
 		int token;
 		substring_t args[MAX_OPT_ARGS];
 
@@ -554,15 +572,34 @@ out_dput:
 	goto out_unlock;
 }
 
+static void ovl_unescape(char *s)
+{
+	char *d = s;
+
+	for (;; s++, d++) {
+		if (*s == '\\')
+			s++;
+		*d = *s;
+		if (!*s)
+			break;
+	}
+}
+
 static int ovl_mount_dir(const char *name, struct path *path)
 {
 	int err;
+	char *tmp = kstrdup(name, GFP_KERNEL);
+
+	if (!tmp)
+		return -ENOMEM;
 
-	err = kern_path(name, LOOKUP_FOLLOW, path);
+	ovl_unescape(tmp);
+	err = kern_path(tmp, LOOKUP_FOLLOW, path);
 	if (err) {
-		pr_err("overlayfs: failed to resolve '%s': %i\n", name, err);
+		pr_err("overlayfs: failed to resolve '%s': %i\n", tmp, err);
 		err = -EINVAL;
 	}
+	kfree(tmp);
 	return err;
 }
 
@@ -776,11 +813,11 @@ static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags,
 
 static struct file_system_type ovl_fs_type = {
 	.owner		= THIS_MODULE,
-	.name		= "overlayfs",
+	.name		= "overlay",
 	.mount		= ovl_mount,
 	.kill_sb	= kill_anon_super,
 };
-MODULE_ALIAS_FS("overlayfs");
+MODULE_ALIAS_FS("overlay");
 
 static int __init ovl_init(void)
 {