Port of sdcardfs to 4.4

Change-Id: I25b99ecf214e72ebf6a57ec3085972542a8d7951
Signed-off-by: Daniel Rosenberg <drosen@google.com>

1 files changed, 63 insertions, 50 deletions

diff --git a/fs/sdcardfs/main.c b/fs/sdcardfs/main.c
index 1fdceffec72c..9d04ae8ceb46 100644
--- a/fs/sdcardfs/main.c
+++ b/fs/sdcardfs/main.c
@@ -156,6 +156,7 @@ invalid_option:
 	return 0;
 }
 
+#if 0
 /*
  * our custom d_alloc_root work-alike
  *
@@ -181,6 +182,7 @@ static struct dentry *sdcardfs_d_alloc_root(struct super_block *sb)
 	}
 	return ret;
 }
+#endif
 
 /*
  * There is no need to lock the sdcardfs_super_info's rwsem as there is no
@@ -195,6 +197,7 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	struct path lower_path;
 	struct sdcardfs_sb_info *sb_info;
 	void *pkgl_id;
+	struct inode *inode;
 
 	printk(KERN_INFO "sdcardfs version 2.0\n");
 
@@ -259,12 +262,18 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	sb->s_magic = SDCARDFS_SUPER_MAGIC;
 	sb->s_op = &sdcardfs_sops;
 
-	/* see comment next to the definition of sdcardfs_d_alloc_root */
-	sb->s_root = sdcardfs_d_alloc_root(sb);
+	/* get a new inode and allocate our root dentry */
+	inode = sdcardfs_iget(sb, lower_path.dentry->d_inode);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto out_sput;
+	}
+	sb->s_root = d_make_root(inode);
 	if (!sb->s_root) {
 		err = -ENOMEM;
-		goto out_sput;
+		goto out_iput;
 	}
+	d_set_d_op(sb->s_root, &sdcardfs_ci_dops);
 
 	/* link the upper and lower dentries */
 	sb->s_root->d_fsdata = NULL;
@@ -275,56 +284,60 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	/* set the lower dentries for s_root */
 	sdcardfs_set_lower_path(sb->s_root, &lower_path);
 
-	/* call interpose to create the upper level inode */
-	err = sdcardfs_interpose(sb->s_root, sb, &lower_path);
-	if (!err) {
-		/* setup permission policy */
-		switch(sb_info->options.derive) {
-			case DERIVE_NONE:
-				setup_derived_state(sb->s_root->d_inode,
-					PERM_ROOT, 0, AID_ROOT, AID_SDCARD_RW, 00775);
-				sb_info->obbpath_s = NULL;
-				break;
-			case DERIVE_LEGACY:
-				/* Legacy behavior used to support internal multiuser layout which
-				 * places user_id at the top directory level, with the actual roots
-				 * just below that. Shared OBB path is also at top level. */
-				setup_derived_state(sb->s_root->d_inode,
-				        PERM_LEGACY_PRE_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771);
-				/* initialize the obbpath string and lookup the path
-				 * sb_info->obb_path will be deactivated by path_put
-				 * on sdcardfs_put_super */
-				sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
-				snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name);
-				err =  prepare_dir(sb_info->obbpath_s,
-							sb_info->options.fs_low_uid,
-							sb_info->options.fs_low_gid, 00755);
-				if(err)
-					printk(KERN_ERR "sdcardfs: %s: %d, error on creating %s\n",
-							__func__,__LINE__, sb_info->obbpath_s);
-				break;
-			case DERIVE_UNIFIED:
-				/* Unified multiuser layout which places secondary user_id under
-				 * /Android/user and shared OBB path under /Android/obb. */
-				setup_derived_state(sb->s_root->d_inode,
-						PERM_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771);
-
-				sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
-				snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name);
-				break;
-		}
-		fix_derived_permission(sb->s_root->d_inode);
+	/*
+	 * No need to call interpose because we already have a positive
+	 * dentry, which was instantiated by d_make_root.  Just need to
+	 * d_rehash it.
+	 */
+	d_rehash(sb->s_root);
 
-		if (!silent)
-			printk(KERN_INFO "sdcardfs: mounted on top of %s type %s\n",
-						dev_name, lower_sb->s_type->name);
-		goto out;
+	/* setup permission policy */
+	switch(sb_info->options.derive) {
+		case DERIVE_NONE:
+			setup_derived_state(sb->s_root->d_inode,
+					PERM_ROOT, 0, AID_ROOT, AID_SDCARD_RW, 00775);
+			sb_info->obbpath_s = NULL;
+			break;
+		case DERIVE_LEGACY:
+			/* Legacy behavior used to support internal multiuser layout which
+			 * places user_id at the top directory level, with the actual roots
+			 * just below that. Shared OBB path is also at top level. */
+			setup_derived_state(sb->s_root->d_inode,
+					PERM_LEGACY_PRE_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771);
+			/* initialize the obbpath string and lookup the path
+			 * sb_info->obb_path will be deactivated by path_put
+			 * on sdcardfs_put_super */
+			sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
+			snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name);
+			err =  prepare_dir(sb_info->obbpath_s,
+					sb_info->options.fs_low_uid,
+					sb_info->options.fs_low_gid, 00755);
+			if(err)
+				printk(KERN_ERR "sdcardfs: %s: %d, error on creating %s\n",
+						__func__,__LINE__, sb_info->obbpath_s);
+			break;
+		case DERIVE_UNIFIED:
+			/* Unified multiuser layout which places secondary user_id under
+			 * /Android/user and shared OBB path under /Android/obb. */
+			setup_derived_state(sb->s_root->d_inode,
+					PERM_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771);
+
+			sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
+			snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name);
+			break;
 	}
-	/* else error: fall through */
+	fix_derived_permission(sb->s_root->d_inode);
+
+	if (!silent)
+		printk(KERN_INFO "sdcardfs: mounted on top of %s type %s\n",
+				dev_name, lower_sb->s_type->name);
+	goto out; /* all is well */
 
-	free_dentry_private_data(sb->s_root);
+	/* no longer needed: free_dentry_private_data(sb->s_root); */
 out_freeroot:
 	dput(sb->s_root);
+out_iput:
+	iput(inode);
 out_sput:
 	/* drop refs we took earlier */
 	atomic_dec(&lower_sb->s_active);
@@ -346,7 +359,7 @@ static struct dentry *mount_nodev_with_options(struct file_system_type *fs_type,
 
 {
 	int error;
-	struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
+	struct super_block *s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 
 	if (IS_ERR(s))
 		return ERR_CAST(s);
@@ -378,7 +391,7 @@ static struct file_system_type sdcardfs_fs_type = {
 	.name		= SDCARDFS_NAME,
 	.mount		= sdcardfs_mount,
 	.kill_sb	= generic_shutdown_super,
-	.fs_flags	= FS_REVAL_DOT,
+	.fs_flags	= 0,
 };
 
 static int __init init_sdcardfs_fs(void)