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  1. 07 12月, 2007 1 次提交
  3. 27 11月, 2007 7 次提交
  5. 18 11月, 2007 2 次提交
    • N
      kernel BUG at fs/nfs/namespace.c:108! - can be triggered by bad server · 4c1fe2f7
      由 Neil Brown 提交于 
      
Hi Trond,

I have discovered that the BUG_ON in nfs_follow_mountpoint:

	BUG_ON(IS_ROOT(dentry));

can be triggered by a misbehaving server.

What happens is the client does a lookup and discoveres that the named
directory has a different fsid, so it initiates a mount.
It then performs a GETATTR on the mounted directory and gets a
different fsid again (due to a bug in the NFS server).
This causes nfs_follow_mountpoint to be called on the newly mounted
root, which triggers the BUG_ON.

To duplicate this, have a directory which contains some mountpoints,
and export that directory with the "crossmnt" flag using nfs-utils
1.1.1 (or 1.1.0 I think)

The GETATTR on the root of the mounted filesystem will return the
information for the top exportpoint, while a lookup will return the
correct information.  This difference causes the NFS client to BUG.

I think the best way to fix this is to trap this possibility early, so
just before completing the mount in the NFS client, check that it isn't
going to use nfs_mountpoint_inode_operations.
As long as i_op will never change once set (is that true?), this
should be adequately safe.

The following patch shows a possible approach, and it works for me.
i.e. when the NFS server is misbehaving, I get ESTALE on those
mountpoints, while when the NFS server is working correctly, I get
correct behaviour on the client.

NeilBrown
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
      4c1fe2f7
    • T
      NFS: Fix the ustat() regression · b09b9417
      由 Trond Myklebust 提交于 
      Since 2.6.18, the superblock sb->s_root has been a dummy dentry with a
dummy inode. This breaks ustat(), which actually uses sb->s_root in a
vfstat() call.

Fix this by making the s_root a dummy alias to the directory inode that was
used when creating the superblock.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
      b09b9417
  7. 24 10月, 2007 1 次提交
  9. 22 10月, 2007 2 次提交
  11. 20 10月, 2007 7 次提交
  13. 19 10月, 2007 1 次提交
  15. 17 10月, 2007 5 次提交
  17. 12 10月, 2007 1 次提交
  19. 10 10月, 2007 13 次提交