From e9cc6c234bfe414ef36f484e3ad8be621854c440 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Wed, 2 Jan 2008 13:28:57 -0500
Subject: [PATCH] NFS: Fix a possible Oops in fs/nfs/super.c
Sigh... commit 4584f520e1f773082ef44ff4f8969a5d992b16ec (NFS: Fix NFS
mountpoint crossing...) had a slight flaw: server can be NULL if sget()
returned an existing superblock.
Fix the fix by dereferencing s->s_fs_info.
Thanks to Coverity/Adrian Bunk and Frank Filz for spotting the bug.
(See http://bugzilla.kernel.org/show_bug.cgi?id=9647)
Also add in the same namespace Oops fix for NFSv4 in both the mountpoint
crossing case, and the referral case.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
fs/nfs/super.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index ea929207f2741..0b0c72a072ffd 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1475,7 +1475,7 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
error = PTR_ERR(mntroot);
goto error_splat_super;
}
- if (mntroot->d_inode->i_op != server->nfs_client->rpc_ops->dir_inode_ops) {
+ if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
dput(mntroot);
error = -ESTALE;
goto error_splat_super;
@@ -1826,6 +1826,11 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
error = PTR_ERR(mntroot);
goto error_splat_super;
}
+ if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
+ dput(mntroot);
+ error = -ESTALE;
+ goto error_splat_super;
+ }
s->s_flags |= MS_ACTIVE;
mnt->mnt_sb = s;
@@ -1900,6 +1905,11 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
error = PTR_ERR(mntroot);
goto error_splat_super;
}
+ if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
+ dput(mntroot);
+ error = -ESTALE;
+ goto error_splat_super;
+ }
s->s_flags |= MS_ACTIVE;
mnt->mnt_sb = s;
--
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