From: Lee Duncan <lduncan@suse.com>
Date: Fri, 6 Apr 2018 11:31:41 -0700
Subject: scsi: target: prefer dbroot of /etc/target over /var/target
Git-commit: 78a6295c71cb276f8ab0bfc786f3543a4e756a8f
Patch-mainline: v4.18-rc1
References: bsc#1111928

The target database root directory, dbroot, has defaulted to /var/target
for a while, but its main client, targetcli-fb, has been moving it to
/etc/target for quite some time. With the plethora of target drivers now
appearing, it has become more difficult to initialize this attribute
before use by any child drivers.

If the directory /etc/target exists, use that as the DB root. Otherwise,
fall back to using /var/target.

The ability to override this dbroot attribute still exists via sysfs.

Signed-off-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
 drivers/target/target_core_configfs.c |   25 +++++++++++++++++++++++++
 drivers/target/target_core_internal.h |    1 +
 2 files changed, 26 insertions(+)

--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -155,6 +155,8 @@ static ssize_t target_core_item_dbroot_s
 
 	mutex_unlock(&g_tf_lock);
 
+	pr_debug("Target_Core_ConfigFS: db_root set to %s\n", db_root);
+
 	return read_bytes;
 }
 
@@ -3207,6 +3209,27 @@ void target_setup_backend_cits(struct ta
 	target_core_setup_dev_stat_cit(tb);
 }
 
+static void target_init_dbroot(void)
+{
+	struct file *fp;
+
+	snprintf(db_root_stage, DB_ROOT_LEN, DB_ROOT_PREFERRED);
+	fp = filp_open(db_root_stage, O_RDONLY, 0);
+	if (IS_ERR(fp)) {
+		pr_err("db_root: cannot open: %s\n", db_root_stage);
+		return;
+	}
+	if (!S_ISDIR(file_inode(fp)->i_mode)) {
+		filp_close(fp, NULL);
+		pr_err("db_root: not a valid directory: %s\n", db_root_stage);
+		return;
+	}
+	filp_close(fp, NULL);
+
+	strncpy(db_root, db_root_stage, DB_ROOT_LEN);
+	pr_debug("Target_Core_ConfigFS: db_root set to %s\n", db_root);
+}
+
 static int __init target_core_init_configfs(void)
 {
 	struct configfs_subsystem *subsys = &target_core_fabrics;
@@ -3287,6 +3310,8 @@ static int __init target_core_init_confi
 	if (ret < 0)
 		goto out;
 
+	target_init_dbroot();
+
 	return 0;
 
 out:
--- a/drivers/target/target_core_internal.h
+++ b/drivers/target/target_core_internal.h
@@ -164,6 +164,7 @@ extern struct se_portal_group xcopy_pt_t
 /* target_core_configfs.c */
 #define DB_ROOT_LEN		4096
 #define	DB_ROOT_DEFAULT		"/var/target"
+#define	DB_ROOT_PREFERRED	"/etc/target"
 
 extern char db_root[];