From: a17671 <a17671@motorola.com>
Date: Tue, 18 Sep 2018 09:30:19 +0000 (+0800)
Subject: Porting the sdcard panic fix from qcom
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c004983deef12d86a41869c46ed79eed45827acc;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

Porting the sdcard panic fix from qcom

Porting the change 226f96b0 from QCOM
Fix potential crash when reserved_mb is not zero
Author: Lianjun Huang <huanglianjun@vivo.com>
sdcardfs_mkdir() calls check_min_free_space(). When
reserved_mb is not zero, a negative dentry will be passed to
ext4_statfs at last and ext4_statfs() will crash. The parent dentry
is possitive. So we use the parrent dentry to check free space.

Change-Id: I0c7c6e38cf116660bc573a7e81a679366aa6c334
Signed-off-by: a17671 <a17671@motorola.com>
Reviewed-on: https://gerrit.mot.com/1242998
SLTApproved: Slta Waiver
SME-Granted: SME Approvals Granted
Tested-by: Jira Key
Reviewed-by: Master Yoda
Reviewed-by: Xiangpo Zhao <zhaoxp3@motorola.com>
Submit-Approved: Jira Key
---

diff --git a/fs/sdcardfs/inode.c b/fs/sdcardfs/inode.c
index 4dd681e0d59d..6015d16576b2 100644
--- a/fs/sdcardfs/inode.c
+++ b/fs/sdcardfs/inode.c
@@ -66,6 +66,7 @@ static int sdcardfs_create(struct inode *dir, struct dentry *dentry,
 	struct dentry *lower_dentry;
 	struct vfsmount *lower_dentry_mnt;
 	struct dentry *lower_parent_dentry = NULL;
+	struct dentry *parent_dentry = NULL;
 	struct path lower_path;
 	const struct cred *saved_cred = NULL;
 	struct fs_struct *saved_fs;
@@ -82,6 +83,14 @@ static int sdcardfs_create(struct inode *dir, struct dentry *dentry,
 	if (!saved_cred)
 		return -ENOMEM;
 
+	parent_dentry = dget_parent(dentry);
+        if (!check_min_free_space(parent_dentry, 0, 1)) {
+                pr_err("sdcardfs: No minimum free space.\n");
+                err = -ENOSPC;
+                dput(parent_dentry);
+                goto out_revert;
+        }
+        dput(parent_dentry);
 	sdcardfs_get_lower_path(dentry, &lower_path);
 	lower_dentry = lower_path.dentry;
 	lower_dentry_mnt = lower_path.mnt;
@@ -122,7 +131,8 @@ out:
 out_unlock:
 	unlock_dir(lower_parent_dentry);
 	sdcardfs_put_lower_path(dentry, &lower_path);
-	revert_fsids(saved_cred);
+out_revert:	
+        revert_fsids(saved_cred);
 out_eacces:
 	return err;
 }