Linux-libre 4.5-gnu

6 files changed, 110 insertions, 79 deletions

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index eff6319d5..d894e7cd9 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -248,9 +248,9 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
 	if (err)
 		goto out_cleanup;
 
-	mutex_lock(&newdentry->d_inode->i_mutex);
+	inode_lock(newdentry->d_inode);
 	err = ovl_set_attr(newdentry, stat);
-	mutex_unlock(&newdentry->d_inode->i_mutex);
+	inode_unlock(newdentry->d_inode);
 	if (err)
 		goto out_cleanup;
 
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 692ceda3b..52f6de5d4 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -167,7 +167,7 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
 	struct dentry *newdentry;
 	int err;
 
-	mutex_lock_nested(&udir->i_mutex, I_MUTEX_PARENT);
+	inode_lock_nested(udir, I_MUTEX_PARENT);
 	newdentry = lookup_one_len(dentry->d_name.name, upperdir,
 				   dentry->d_name.len);
 	err = PTR_ERR(newdentry);
@@ -185,7 +185,7 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
 out_dput:
 	dput(newdentry);
 out_unlock:
-	mutex_unlock(&udir->i_mutex);
+	inode_unlock(udir);
 	return err;
 }
 
@@ -258,9 +258,9 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
 	if (err)
 		goto out_cleanup;
 
-	mutex_lock(&opaquedir->d_inode->i_mutex);
+	inode_lock(opaquedir->d_inode);
 	err = ovl_set_attr(opaquedir, &stat);
-	mutex_unlock(&opaquedir->d_inode->i_mutex);
+	inode_unlock(opaquedir->d_inode);
 	if (err)
 		goto out_cleanup;
 
@@ -599,7 +599,7 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
 	struct dentry *upper = ovl_dentry_upper(dentry);
 	int err;
 
-	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
+	inode_lock_nested(dir, I_MUTEX_PARENT);
 	err = -ESTALE;
 	if (upper->d_parent == upperdir) {
 		/* Don't let d_delete() think it can reset d_inode */
@@ -618,8 +618,9 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
 	 * sole user of this dentry.  Too tricky...  Just unhash for
 	 * now.
 	 */
-	d_drop(dentry);
-	mutex_unlock(&dir->i_mutex);
+	if (!err)
+		d_drop(dentry);
+	inode_unlock(dir);
 
 	return err;
 }
@@ -903,6 +904,13 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
 	if (!overwrite && new_is_dir && !old_opaque && new_opaque)
 		ovl_remove_opaque(newdentry);
 
+	/*
+	 * Old dentry now lives in different location. Dentries in
+	 * lowerstack are stale. We cannot drop them here because
+	 * access to them is lockless. This could be only pure upper
+	 * or opaque directory - numlower is zero. Or upper non-dir
+	 * entry - its pureness is tracked by flag opaque.
+	 */
 	if (old_opaque != new_opaque) {
 		ovl_dentry_set_opaque(old, new_opaque);
 		if (!overwrite)
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index b29036aa8..a4ff5d0d7 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -63,9 +63,11 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
 	if (!err) {
 		upperdentry = ovl_dentry_upper(dentry);
 
-		mutex_lock(&upperdentry->d_inode->i_mutex);
+		inode_lock(upperdentry->d_inode);
 		err = notify_change(upperdentry, attr, NULL);
-		mutex_unlock(&upperdentry->d_inode->i_mutex);
+		if (!err)
+			ovl_copyattr(upperdentry->d_inode, dentry->d_inode);
+		inode_unlock(upperdentry->d_inode);
 	}
 	ovl_drop_write(dentry);
 out:
@@ -108,6 +110,29 @@ int ovl_permission(struct inode *inode, int mask)
 
 	realdentry = ovl_entry_real(oe, &is_upper);
 
+	if (ovl_is_default_permissions(inode)) {
+		struct kstat stat;
+		struct path realpath = { .dentry = realdentry };
+
+		if (mask & MAY_NOT_BLOCK)
+			return -ECHILD;
+
+		realpath.mnt = ovl_entry_mnt_real(oe, inode, is_upper);
+
+		err = vfs_getattr(&realpath, &stat);
+		if (err)
+			return err;
+
+		if ((stat.mode ^ inode->i_mode) & S_IFMT)
+			return -ESTALE;
+
+		inode->i_mode = stat.mode;
+		inode->i_uid = stat.uid;
+		inode->i_gid = stat.gid;
+
+		return generic_permission(inode, mask);
+	}
+
 	/* Careful in RCU walk mode */
 	realinode = ACCESS_ONCE(realdentry->d_inode);
 	if (!realinode) {
@@ -144,57 +169,23 @@ out_dput:
 	return err;
 }
 
-
-struct ovl_link_data {
-	struct dentry *realdentry;
-	void *cookie;
-};
-
-static const char *ovl_follow_link(struct dentry *dentry, void **cookie)
+static const char *ovl_get_link(struct dentry *dentry,
+				struct inode *inode,
+				struct delayed_call *done)
 {
 	struct dentry *realdentry;
 	struct inode *realinode;
-	struct ovl_link_data *data = NULL;
-	const char *ret;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
 
 	realdentry = ovl_dentry_real(dentry);
 	realinode = realdentry->d_inode;
 
-	if (WARN_ON(!realinode->i_op->follow_link))
+	if (WARN_ON(!realinode->i_op->get_link))
 		return ERR_PTR(-EPERM);
 
-	if (realinode->i_op->put_link) {
-		data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL);
-		if (!data)
-			return ERR_PTR(-ENOMEM);
-		data->realdentry = realdentry;
-	}
-
-	ret = realinode->i_op->follow_link(realdentry, cookie);
-	if (IS_ERR_OR_NULL(ret)) {
-		kfree(data);
-		return ret;
-	}
-
-	if (data)
-		data->cookie = *cookie;
-
-	*cookie = data;
-
-	return ret;
-}
-
-static void ovl_put_link(struct inode *unused, void *c)
-{
-	struct inode *realinode;
-	struct ovl_link_data *data = c;
-
-	if (!data)
-		return;
-
-	realinode = data->realdentry->d_inode;
-	realinode->i_op->put_link(realinode, data->cookie);
-	kfree(data);
+	return realinode->i_op->get_link(realdentry, realinode, done);
 }
 
 static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
@@ -391,8 +382,7 @@ static const struct inode_operations ovl_file_inode_operations = {
 
 static const struct inode_operations ovl_symlink_inode_operations = {
 	.setattr	= ovl_setattr,
-	.follow_link	= ovl_follow_link,
-	.put_link	= ovl_put_link,
+	.get_link	= ovl_get_link,
 	.readlink	= ovl_readlink,
 	.getattr	= ovl_getattr,
 	.setxattr	= ovl_setxattr,
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index e17154aea..99b4168c3 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -142,7 +142,10 @@ struct dentry *ovl_dentry_upper(struct dentry *dentry);
 struct dentry *ovl_dentry_lower(struct dentry *dentry);
 struct dentry *ovl_dentry_real(struct dentry *dentry);
 struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper);
+struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode,
+				    bool is_upper);
 struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
+bool ovl_is_default_permissions(struct inode *inode);
 void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
 struct dentry *ovl_workdir(struct dentry *dentry);
 int ovl_want_write(struct dentry *dentry);
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index adcb1398c..fdaf28f75 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -228,7 +228,7 @@ static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd)
 				dput(dentry);
 			}
 		}
-		mutex_unlock(&dir->d_inode->i_mutex);
+		inode_unlock(dir->d_inode);
 	}
 	revert_creds(old_cred);
 	put_cred(override_cred);
@@ -399,7 +399,7 @@ static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
 	loff_t res;
 	struct ovl_dir_file *od = file->private_data;
 
-	mutex_lock(&file_inode(file)->i_mutex);
+	inode_lock(file_inode(file));
 	if (!file->f_pos)
 		ovl_dir_reset(file);
 
@@ -429,7 +429,7 @@ static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
 		res = offset;
 	}
 out_unlock:
-	mutex_unlock(&file_inode(file)->i_mutex);
+	inode_unlock(file_inode(file));
 
 	return res;
 }
@@ -454,10 +454,10 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
 			ovl_path_upper(dentry, &upperpath);
 			realfile = ovl_path_open(&upperpath, O_RDONLY);
 			smp_mb__before_spinlock();
-			mutex_lock(&inode->i_mutex);
+			inode_lock(inode);
 			if (!od->upperfile) {
 				if (IS_ERR(realfile)) {
-					mutex_unlock(&inode->i_mutex);
+					inode_unlock(inode);
 					return PTR_ERR(realfile);
 				}
 				od->upperfile = realfile;
@@ -467,7 +467,7 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
 					fput(realfile);
 				realfile = od->upperfile;
 			}
-			mutex_unlock(&inode->i_mutex);
+			inode_unlock(inode);
 		}
 	}
 
@@ -479,9 +479,9 @@ static int ovl_dir_release(struct inode *inode, struct file *file)
 	struct ovl_dir_file *od = file->private_data;
 
 	if (od->cache) {
-		mutex_lock(&inode->i_mutex);
+		inode_lock(inode);
 		ovl_cache_put(od, file->f_path.dentry);
-		mutex_unlock(&inode->i_mutex);
+		inode_unlock(inode);
 	}
 	fput(od->realfile);
 	if (od->upperfile)
@@ -557,7 +557,7 @@ void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list)
 {
 	struct ovl_cache_entry *p;
 
-	mutex_lock_nested(&upper->d_inode->i_mutex, I_MUTEX_CHILD);
+	inode_lock_nested(upper->d_inode, I_MUTEX_CHILD);
 	list_for_each_entry(p, list, l_node) {
 		struct dentry *dentry;
 
@@ -575,5 +575,5 @@ void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list)
 			ovl_cleanup(upper->d_inode, dentry);
 		dput(dentry);
 	}
-	mutex_unlock(&upper->d_inode->i_mutex);
+	inode_unlock(upper->d_inode);
 }
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index f42c9407f..619ad4b01 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -16,6 +16,7 @@
 #include <linux/slab.h>
 #include <linux/parser.h>
 #include <linux/module.h>
+#include <linux/pagemap.h>
 #include <linux/sched.h>
 #include <linux/statfs.h>
 #include <linux/seq_file.h>
@@ -25,12 +26,11 @@ MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
 MODULE_DESCRIPTION("Overlay filesystem");
 MODULE_LICENSE("GPL");
 
-#define OVERLAYFS_SUPER_MAGIC 0x794c7630
-
 struct ovl_config {
 	char *lowerdir;
 	char *upperdir;
 	char *workdir;
+	bool default_permissions;
 };
 
 /* private information held for overlayfs's superblock */
@@ -76,12 +76,14 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry)
 	if (oe->__upperdentry) {
 		type = __OVL_PATH_UPPER;
 
-		if (oe->numlower) {
-			if (S_ISDIR(dentry->d_inode->i_mode))
-				type |= __OVL_PATH_MERGE;
-		} else if (!oe->opaque) {
+		/*
+		 * Non-dir dentry can hold lower dentry from previous
+		 * location. Its purity depends only on opaque flag.
+		 */
+		if (oe->numlower && S_ISDIR(dentry->d_inode->i_mode))
+			type |= __OVL_PATH_MERGE;
+		else if (!oe->opaque)
 			type |= __OVL_PATH_PURE;
-		}
 	} else {
 		if (oe->numlower > 1)
 			type |= __OVL_PATH_MERGE;
@@ -155,6 +157,18 @@ struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper)
 	return realdentry;
 }
 
+struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode,
+				    bool is_upper)
+{
+	if (is_upper) {
+		struct ovl_fs *ofs = inode->i_sb->s_fs_info;
+
+		return ofs->upper_mnt;
+	} else {
+		return oe->numlower ? oe->lowerstack[0].mnt : NULL;
+	}
+}
+
 struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
 {
 	struct ovl_entry *oe = dentry->d_fsdata;
@@ -162,6 +176,13 @@ struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
 	return oe->cache;
 }
 
+bool ovl_is_default_permissions(struct inode *inode)
+{
+	struct ovl_fs *ofs = inode->i_sb->s_fs_info;
+
+	return ofs->config.default_permissions;
+}
+
 void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
 {
 	struct ovl_entry *oe = dentry->d_fsdata;
@@ -210,7 +231,7 @@ void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
 {
 	struct ovl_entry *oe = dentry->d_fsdata;
 
-	WARN_ON(!mutex_is_locked(&upperdentry->d_parent->d_inode->i_mutex));
+	WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
 	WARN_ON(oe->__upperdentry);
 	BUG_ON(!upperdentry->d_inode);
 	/*
@@ -225,7 +246,7 @@ void ovl_dentry_version_inc(struct dentry *dentry)
 {
 	struct ovl_entry *oe = dentry->d_fsdata;
 
-	WARN_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
+	WARN_ON(!inode_is_locked(dentry->d_inode));
 	oe->version++;
 }
 
@@ -233,7 +254,7 @@ u64 ovl_dentry_version_get(struct dentry *dentry)
 {
 	struct ovl_entry *oe = dentry->d_fsdata;
 
-	WARN_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
+	WARN_ON(!inode_is_locked(dentry->d_inode));
 	return oe->version;
 }
 
@@ -322,6 +343,7 @@ static const struct dentry_operations ovl_dentry_operations = {
 
 static const struct dentry_operations ovl_reval_dentry_operations = {
 	.d_release = ovl_dentry_release,
+	.d_select_inode = ovl_d_select_inode,
 	.d_revalidate = ovl_dentry_revalidate,
 	.d_weak_revalidate = ovl_dentry_weak_revalidate,
 };
@@ -356,9 +378,9 @@ static inline struct dentry *ovl_lookup_real(struct dentry *dir,
 {
 	struct dentry *dentry;
 
-	mutex_lock(&dir->d_inode->i_mutex);
+	inode_lock(dir->d_inode);
 	dentry = lookup_one_len(name->name, dir, name->len);
-	mutex_unlock(&dir->d_inode->i_mutex);
+	inode_unlock(dir->d_inode);
 
 	if (IS_ERR(dentry)) {
 		if (PTR_ERR(dentry) == -ENOENT)
@@ -595,6 +617,8 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
 		seq_show_option(m, "upperdir", ufs->config.upperdir);
 		seq_show_option(m, "workdir", ufs->config.workdir);
 	}
+	if (ufs->config.default_permissions)
+		seq_puts(m, ",default_permissions");
 	return 0;
 }
 
@@ -619,6 +643,7 @@ enum {
 	OPT_LOWERDIR,
 	OPT_UPPERDIR,
 	OPT_WORKDIR,
+	OPT_DEFAULT_PERMISSIONS,
 	OPT_ERR,
 };
 
@@ -626,6 +651,7 @@ static const match_table_t ovl_tokens = {
 	{OPT_LOWERDIR,			"lowerdir=%s"},
 	{OPT_UPPERDIR,			"upperdir=%s"},
 	{OPT_WORKDIR,			"workdir=%s"},
+	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},
 	{OPT_ERR,			NULL}
 };
 
@@ -686,6 +712,10 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
 				return -ENOMEM;
 			break;
 
+		case OPT_DEFAULT_PERMISSIONS:
+			config->default_permissions = true;
+			break;
+
 		default:
 			pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p);
 			return -EINVAL;
@@ -717,7 +747,7 @@ static struct dentry *ovl_workdir_create(struct vfsmount *mnt,
 	if (err)
 		return ERR_PTR(err);
 
-	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
+	inode_lock_nested(dir, I_MUTEX_PARENT);
 retry:
 	work = lookup_one_len(OVL_WORKDIR_NAME, dentry,
 			      strlen(OVL_WORKDIR_NAME));
@@ -743,7 +773,7 @@ retry:
 			goto out_dput;
 	}
 out_unlock:
-	mutex_unlock(&dir->i_mutex);
+	inode_unlock(dir);
 	mnt_drop_write(mnt);
 
 	return work;