Linux-libre 4.5-gnu

1 files changed, 44 insertions, 14 deletions

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;