[3.13.y.z extended stable] Patch "ext4: add ext4_iget_normal() which is to be used for dir tree lookups" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    ext4: add ext4_iget_normal() which is to be used for dir tree lookups

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 7bc7ed11653e675843dfa64bd9343e6e448e3faf Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso at mit.edu>
Date: Sun, 5 Oct 2014 22:56:00 -0400
Subject: ext4: add ext4_iget_normal() which is to be used for dir tree lookups

commit f4bb2981024fc91b23b4d09a8817c415396dbabb upstream.

If there is a corrupted file system which has directory entries that
point at reserved, metadata inodes, prohibit them from being used by
treating them the same way we treat Boot Loader inodes --- that is,
mark them to be bad inodes.  This prohibits them from being opened,
deleted, or modified via chmod, chown, utimes, etc.

In particular, this prevents a corrupted file system which has a
directory entry which points at the journal inode from being deleted
and its blocks released, after which point Much Hilarity Ensues.

Reported-by: Sami Liedes <sami.liedes at iki.fi>
Signed-off-by: Theodore Ts'o <tytso at mit.edu>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/ext4/ext4.h  | 1 +
 fs/ext4/inode.c | 7 +++++++
 fs/ext4/namei.c | 4 ++--
 fs/ext4/super.c | 2 +-
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index e531054..c9d0794 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2110,6 +2110,7 @@ int do_journal_get_write_access(handle_t *handle,
 #define CONVERT_INLINE_DATA	 2

 extern struct inode *ext4_iget(struct super_block *, unsigned long);
+extern struct inode *ext4_iget_normal(struct super_block *, unsigned long);
 extern int  ext4_write_inode(struct inode *, struct writeback_control *);
 extern int  ext4_setattr(struct dentry *, struct iattr *);
 extern int  ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 37d3b1a..a4c4f38 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4260,6 +4260,13 @@ bad_inode:
 	return ERR_PTR(ret);
 }

+struct inode *ext4_iget_normal(struct super_block *sb, unsigned long ino)
+{
+	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
+		return ERR_PTR(-EIO);
+	return ext4_iget(sb, ino);
+}
+
 static int ext4_inode_blocks_set(handle_t *handle,
 				struct ext4_inode *raw_inode,
 				struct ext4_inode_info *ei)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index d4fa3ed..5bfbf94 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1430,7 +1430,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
 					 dentry->d_name.name);
 			return ERR_PTR(-EIO);
 		}
-		inode = ext4_iget(dir->i_sb, ino);
+		inode = ext4_iget_normal(dir->i_sb, ino);
 		if (inode == ERR_PTR(-ESTALE)) {
 			EXT4_ERROR_INODE(dir,
 					 "deleted inode referenced: %u",
@@ -1461,7 +1461,7 @@ struct dentry *ext4_get_parent(struct dentry *child)
 		return ERR_PTR(-EIO);
 	}

-	return d_obtain_alias(ext4_iget(child->d_inode->i_sb, ino));
+	return d_obtain_alias(ext4_iget_normal(child->d_inode->i_sb, ino));
 }

 /*
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 5ee03e5d..c888f23 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -996,7 +996,7 @@ static struct inode *ext4_nfs_get_inode(struct super_block *sb,
 	 * Currently we don't know the generation for parent directory, so
 	 * a generation of 0 means "accept any"
 	 */
-	inode = ext4_iget(sb, ino);
+	inode = ext4_iget_normal(sb, ino);
 	if (IS_ERR(inode))
 		return ERR_CAST(inode);
 	if (generation && inode->i_generation != generation) {
--
1.9.1