linux-kernel - [PATCH 1/2] fs: avoid fdput() after failed fdget() in ksys_sync_file

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Message-Id: <31be6e0896eba59c06eb9d3d137b214f7220cc53.1588894359.git.skhan@linuxfoundation.org>
Date:   Thu,  7 May 2020 17:57:09 -0600
From:   Shuah Khan <skhan@...uxfoundation.org>
To:     viro@...iv.linux.org.uk, axboe@...nel.dk, zohar@...ux.vnet.ibm.com,
        mcgrof@...nel.org, keescook@...omium.org
Cc:     Shuah Khan <skhan@...uxfoundation.org>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] fs: avoid fdput() after failed fdget() in ksys_sync_file_range()

Fix ksys_sync_file_range() to avoid fdput() after a failed fdget().
fdput() doesn't do fput() on this file since FDPUT_FPUT isn't set
in fd.flags. Fix it anyway since failed fdget() doesn't require
a fdput().

This was introdcued in a commit to add sync_file_range() helper.

Fixes: 22f96b3808c1 ("fs: add sync_file_range() helper")
Signed-off-by: Shuah Khan <skhan@...uxfoundation.org>
---
 fs/sync.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/sync.c b/fs/sync.c
index 4d1ff010bc5a..faaff835ef12 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -369,10 +369,11 @@ int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
 
 	ret = -EBADF;
 	f = fdget(fd);
-	if (f.file)
+	if (f.file) {
 		ret = sync_file_range(f.file, offset, nbytes, flags);
+		fdput(f);
+	}
 
-	fdput(f);
 	return ret;
 }
 
-- 
2.20.1