linux-kernel - [PATCH 3.16 181/233] excessive checks in ufs_write_failed() and ufs_evict

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Date:   Sat, 09 Sep 2017 22:47:15 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Al Viro" <viro@...iv.linux.org.uk>
Subject: [PATCH 3.16 181/233] excessive checks in ufs_write_failed() and
 ufs_evict_inode()

3.16.48-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Al Viro <viro@...iv.linux.org.uk>

commit babef37dccbaa49249a22bae9150686815d7be71 upstream.

As it is, short copy in write() to append-only file will fail
to truncate the excessive allocated blocks.  As the matter of
fact, all checks in ufs_truncate_blocks() are either redundant
or wrong for that caller.  As for the only other caller
(ufs_evict_inode()), we only need the file type checks there.

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
[bwh: Backported to 3.16:
 - No functions need to be renamed
 - Adjust filenames, context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
--- a/fs/ufs/inode.c
+++ b/fs/ufs/inode.c
@@ -894,7 +894,10 @@ void ufs_evict_inode(struct inode * inod
 		ufs_update_inode(inode, IS_SYNC(inode));
 		old_i_size = inode->i_size;
 		inode->i_size = 0;
-		if (inode->i_blocks && ufs_truncate(inode, old_i_size))
+		if (inode->i_blocks &&
+		    (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+		     S_ISLNK(inode->i_mode)) &&
+		    ufs_truncate(inode, old_i_size))
 			ufs_warning(inode->i_sb, __func__, "ufs_truncate failed\n");
 		unlock_ufs(inode->i_sb);
 	}
--- a/fs/ufs/truncate.c
+++ b/fs/ufs/truncate.c
@@ -451,12 +451,6 @@ int ufs_truncate(struct inode *inode, lo
 	     inode->i_ino, (unsigned long long)i_size_read(inode),
 	     (unsigned long long)old_i_size);
 
-	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
-	      S_ISLNK(inode->i_mode)))
-		return -EINVAL;
-	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
-		return -EPERM;
-
 	err = ufs_alloc_lastblock(inode);
 
 	if (err) {