From: Vasily Averin <vvs@virtuozzo.com>
Date: Fri, 9 Nov 2018 16:34:40 +0000 (-0500)
Subject: ext4: missing !bh check in ext4_xattr_inode_write()
X-Git-Tag: v5.4-rc1~2221^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=eb6984fa4ce2837dcb1f66720a600f31b0bb3739;p=platform%2Fkernel%2Flinux-rpi.git

ext4: missing !bh check in ext4_xattr_inode_write()

According to Ted Ts'o ext4_getblk() called in ext4_xattr_inode_write()
should not return bh = NULL

The only time that bh could be NULL, then, would be in the case of
something really going wrong; a programming error elsewhere (perhaps a
wild pointer dereference) or I/O error causing on-disk file system
corruption (although that would be highly unlikely given that we had
*just* allocated the blocks and so the metadata blocks in question
probably would still be in the cache).

Fixes: e50e5129f384 ("ext4: xattr-in-inode support")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 4.13
---

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 0b96886..7643d52 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1384,6 +1384,12 @@ retry:
 		bh = ext4_getblk(handle, ea_inode, block, 0);
 		if (IS_ERR(bh))
 			return PTR_ERR(bh);
+		if (!bh) {
+			WARN_ON_ONCE(1);
+			EXT4_ERROR_INODE(ea_inode,
+					 "ext4_getblk() return bh = NULL");
+			return -EFSCORRUPTED;
+		}
 		ret = ext4_journal_get_write_access(handle, bh);
 		if (ret)
 			goto out;