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| author | Gusev Vitaliy <gusev.vitaliy@nexenta.com> | 2011-03-23 00:40:25 +0300 |
|---|---|---|
| committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2011-03-22 20:00:25 -0400 |
| commit | 4667058b772857069378aa8f417203156e315e82 (patch) | |
| tree | 07c6aa01118f2a36748d29917029884b095e000c | |
| parent | 246408dcd5dfeef2df437ccb0ef4d6ee87805f58 (diff) | |
| download | lwn-4667058b772857069378aa8f417203156e315e82.tar.gz lwn-4667058b772857069378aa8f417203156e315e82.zip | |
nfs4: Fix NULL dereference at d_alloc_and_lookup()
d_alloc_and_lookup() calls i_op->lookup method due to
rootfh changes his fsid.
During mount i_op of NFS root inode is set to
nfs_mountpoint_inode_operations, if rpc_ops->getroot()
and rpc_ops->getattr() return different fsid.
After that nfs_follow_remote_path() raised oops:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [< (null)>] (null)
stack trace:
d_alloc_and_lookup+0x4c/0x74
do_lookup+0x1e3/0x280
link_path_walk+0x12e/0xab0
nfs4_remote_get_sb+0x56/0x2c0 [nfs]
path_walk+0x67/0xe0
vfs_path_lookup+0x8e/0x100
nfs_follow_remote_path+0x16f/0x3e0 [nfs]
nfs4_try_mount+0x6f/0xd0 [nfs]
nfs_get_sb+0x269/0x400 [nfs]
vfs_kern_mount+0x8a/0x1f0
do_kern_mount+0x52/0x130
do_mount+0x20a/0x260
sys_mount+0x90/0xe0
system_call_fastpath+0x16/0x1b
So just refresh fsid, as RFC3530 doesn't specify behavior
in case of rootfh changes fsid.
Signed-off-by: Vitaliy Gusev <gusev.vitaliy@nexenta.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| -rw-r--r-- | fs/nfs/getroot.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c index b5ffe8fa291f..79796521cfdc 100644 --- a/fs/nfs/getroot.c +++ b/fs/nfs/getroot.c @@ -199,6 +199,10 @@ struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh) goto out; } + if (fattr->valid & NFS_ATTR_FATTR_FSID && + !nfs_fsid_equal(&server->fsid, &fattr->fsid)) + memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid)); + inode = nfs_fhget(sb, mntfh, fattr); if (IS_ERR(inode)) { dprintk("nfs_get_root: get root inode failed\n"); |