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author | NeilBrown <neilb@suse.com> | 2017-07-05 12:22:20 +1000 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-27 15:08:06 -0700 |
commit | 9ebfb4fa3ab7ea99b5d93305b10ee3714501b465 (patch) | |
tree | a8661bef2d5aaa256c6ccef4f7d922cf8aef6de6 /fs/udf | |
parent | 4dd0aa9ae6d0e948848f87b4c040cea8163a59bf (diff) |
NFS: only invalidate dentrys that are clearly invalid.
commit cc89684c9a265828ce061037f1f79f4a68ccd3f7 upstream.
Since commit bafc9b754f75 ("vfs: More precise tests in d_invalidate")
in v3.18, a return of '0' from ->d_revalidate() will cause the dentry
to be invalidated even if it has filesystems mounted on or it or on a
descendant. The mounted filesystem is unmounted.
This means we need to be careful not to return 0 unless the directory
referred to truly is invalid. So -ESTALE or -ENOENT should invalidate
the directory. Other errors such a -EPERM or -ERESTARTSYS should be
returned from ->d_revalidate() so they are propagated to the caller.
A particular problem can be demonstrated by:
1/ mount an NFS filesystem using NFSv3 on /mnt
2/ mount any other filesystem on /mnt/foo
3/ ls /mnt/foo
4/ turn off network, or otherwise make the server unable to respond
5/ ls /mnt/foo &
6/ cat /proc/$!/stack # note that nfs_lookup_revalidate is in the call stack
7/ kill -9 $! # this results in -ERESTARTSYS being returned
8/ observe that /mnt/foo has been unmounted.
This patch changes nfs_lookup_revalidate() to only treat
-ESTALE from nfs_lookup_verify_inode() and
-ESTALE or -ENOENT from ->lookup()
as indicating an invalid inode. Other errors are returned.
Also nfs_check_inode_attributes() is changed to return -ESTALE rather
than -EIO. This is consistent with the error returned in similar
circumstances from nfs_update_inode().
As this bug allows any user to unmount a filesystem mounted on an NFS
filesystem, this fix is suitable for stable kernels.
Fixes: bafc9b754f75 ("vfs: More precise tests in d_invalidate")
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/udf')
0 files changed, 0 insertions, 0 deletions