linux-kernel - [PATCH] fs: avoid fdput() after failed fdget() in vfs_dedupe_file

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Message-Id: <20180414061658.3774-1-zev@bewilderbeest.net>
Date:   Sat, 14 Apr 2018 01:16:58 -0500
From:   Zev Weiss <zev@...ilderbeest.net>
To:     Alexander Viro <viro@...iv.linux.org.uk>
Cc:     "Darrick J . Wong" <darrick.wong@...cle.com>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Zev Weiss <zev@...ilderbeest.net>
Subject: [PATCH] fs: avoid fdput() after failed fdget() in vfs_dedupe_file_range()

It's a fairly inconsequential bug, since fdput() won't actually try to
fput() the file due to fd.flags (and thus FDPUT_FPUT) being zero in
the failure case, but most other vfs code takes steps to avoid this.

Signed-off-by: Zev Weiss <zev@...ilderbeest.net>
---
 fs/read_write.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index c4eabbfc90df..e83bd9744b5d 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -2023,7 +2023,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
 		ret = mnt_want_write_file(dst_file);
 		if (ret) {
 			info->status = ret;
-			goto next_loop;
+			goto next_fdput;
 		}
 
 		dst_off = info->dest_offset;
@@ -2058,9 +2058,9 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
 
 next_file:
 		mnt_drop_write_file(dst_file);
-next_loop:
+next_fdput:
 		fdput(dst_fd);
-
+next_loop:
 		if (fatal_signal_pending(current))
 			goto out;
 	}
-- 
2.16.3