linux-kernel - [PATCH 2.6.32 15/42] fix sysvfs symlinks

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Message-Id: <20160123141222.636843322@1wt.eu>
Date:	Sat, 23 Jan 2016 15:12:36 +0100
From:	Willy Tarreau <w@....eu>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Al Viro <viro@...iv.linux.org.uk>,
	Ben Hutchings <ben@...adent.org.uk>, Willy Tarreau <w@....eu>
Subject: [PATCH 2.6.32 15/42] fix sysvfs symlinks

2.6.32-longterm review patch.  If anyone has any objections, please let me know.

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

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

commit 0ebf7f10d67a70e120f365018f1c5fce9ddc567d upstream.

The thing got broken back in 2002 - sysvfs does *not* have inline
symlinks; even short ones have bodies stored in the first block
of file.  sysv_symlink() handles that correctly; unfortunately,
attempting to look an existing symlink up will end up confusing
them for inline symlinks, and interpret the block number containing
the body as the body itself.

Nobody has noticed until now, which says something about the level
of testing sysvfs gets ;-/

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
[bwh: Backported to 3.2:
 - Adjust context
 - Also delete unused sysv_fast_symlink_inode_operations]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
(cherry picked from commit 081c769778f7a41f4eb3d633df26ad572575c980)
Signed-off-by: Willy Tarreau <w@....eu>
---
 fs/sysv/Makefile  |  2 +-
 fs/sysv/inode.c   | 10 ++--------
 fs/sysv/symlink.c | 20 --------------------
 3 files changed, 3 insertions(+), 29 deletions(-)
 delete mode 100644 fs/sysv/symlink.c

diff --git a/fs/sysv/Makefile b/fs/sysv/Makefile
index 3591f9d..7a75e70 100644
--- a/fs/sysv/Makefile
+++ b/fs/sysv/Makefile
@@ -5,4 +5,4 @@
 obj-$(CONFIG_SYSV_FS) += sysv.o
 
 sysv-objs := ialloc.o balloc.o inode.o itree.o file.o dir.o \
-	     namei.o super.o symlink.o
+	     namei.o super.o
diff --git a/fs/sysv/inode.c b/fs/sysv/inode.c
index 9824743..cea8804 100644
--- a/fs/sysv/inode.c
+++ b/fs/sysv/inode.c
@@ -174,14 +174,8 @@ void sysv_set_inode(struct inode *inode, dev_t rdev)
 		inode->i_fop = &sysv_dir_operations;
 		inode->i_mapping->a_ops = &sysv_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
-		if (inode->i_blocks) {
-			inode->i_op = &sysv_symlink_inode_operations;
-			inode->i_mapping->a_ops = &sysv_aops;
-		} else {
-			inode->i_op = &sysv_fast_symlink_inode_operations;
-			nd_terminate_link(SYSV_I(inode)->i_data, inode->i_size,
-				sizeof(SYSV_I(inode)->i_data) - 1);
-		}
+		inode->i_op = &sysv_symlink_inode_operations;
+		inode->i_mapping->a_ops = &sysv_aops;
 	} else
 		init_special_inode(inode, inode->i_mode, rdev);
 }
diff --git a/fs/sysv/symlink.c b/fs/sysv/symlink.c
deleted file mode 100644
index 00d2f8a..0000000
--- a/fs/sysv/symlink.c
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- *  linux/fs/sysv/symlink.c
- *
- *  Handling of System V filesystem fast symlinks extensions.
- *  Aug 2001, Christoph Hellwig (hch@...radead.org)
- */
-
-#include "sysv.h"
-#include <linux/namei.h>
-
-static void *sysv_follow_link(struct dentry *dentry, struct nameidata *nd)
-{
-	nd_set_link(nd, (char *)SYSV_I(dentry->d_inode)->i_data);
-	return NULL;
-}
-
-const struct inode_operations sysv_fast_symlink_inode_operations = {
-	.readlink	= generic_readlink,
-	.follow_link	= sysv_follow_link,
-};
-- 
1.7.12.2.21.g234cd45.dirty