From 256fe4162f8b5a1625b8603ca5f7ff79725bfb47 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Mon, 2 Jan 2023 20:14:47 +0100
Subject: [PATCH] udf: Do not update file length for failed writes to inline
 files
Git-commit: 256fe4162f8b5a1625b8603ca5f7ff79725bfb47
Patch-mainline: v6.3-rc1
References: bsc#1213041

When write to inline file fails (or happens only partly), we still
updated length of inline data as if the whole write succeeded. Fix the
update of length of inline data to happen only if the write succeeds.

Reported-by: syzbot+0937935b993956ba28ab@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Jan Kara <jack@suse.cz>

---
 fs/udf/file.c | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/fs/udf/file.c b/fs/udf/file.c
index 5c659e23e578..8be51161f3e5 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -149,26 +149,24 @@ static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		goto out;
 
 	down_write(&iinfo->i_data_sem);
-	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
-		loff_t end = iocb->ki_pos + iov_iter_count(from);
-
-		if (inode->i_sb->s_blocksize <
-				(udf_file_entry_alloc_offset(inode) + end)) {
-			err = udf_expand_file_adinicb(inode);
-			if (err) {
-				inode_unlock(inode);
-				udf_debug("udf_expand_adinicb: err=%d\n", err);
-				return err;
-			}
-		} else {
-			iinfo->i_lenAlloc = max(end, inode->i_size);
-			up_write(&iinfo->i_data_sem);
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB &&
+	    inode->i_sb->s_blocksize < (udf_file_entry_alloc_offset(inode) +
+				 iocb->ki_pos + iov_iter_count(from))) {
+		err = udf_expand_file_adinicb(inode);
+		if (err) {
+			inode_unlock(inode);
+			udf_debug("udf_expand_adinicb: err=%d\n", err);
+			return err;
 		}
 	} else
 		up_write(&iinfo->i_data_sem);
 
 	retval = __generic_file_write_iter(iocb, from);
 out:
+	down_write(&iinfo->i_data_sem);
+	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB && retval > 0)
+		iinfo->i_lenAlloc = inode->i_size;
+	up_write(&iinfo->i_data_sem);
 	inode_unlock(inode);
 
 	if (retval > 0) {
-- 
2.35.3