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| author | NeilBrown <neilb@suse.com> | 2017-07-05 02:22:20 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-27 22:08:06 (GMT) |
| commit | 9ebfb4fa3ab7ea99b5d93305b10ee3714501b465 (patch) | |
| tree | a8661bef2d5aaa256c6ccef4f7d922cf8aef6de6 /fs/nfs/inode.c | |
| parent | 4dd0aa9ae6d0e948848f87b4c040cea8163a59bf (diff) | |
| download | linux-9ebfb4fa3ab7ea99b5d93305b10ee3714501b465.tar.xz | |
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/nfs/inode.c')
| -rw-r--r-- | fs/nfs/inode.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index bf4ec5e..76ae256 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -1278,9 +1278,9 @@ static int nfs_check_inode_attributes(struct inode *inode, struct nfs_fattr *fat return 0; /* Has the inode gone and changed behind our back? */ if ((fattr->valid & NFS_ATTR_FATTR_FILEID) && nfsi->fileid != fattr->fileid) - return -EIO; + return -ESTALE; if ((fattr->valid & NFS_ATTR_FATTR_TYPE) && (inode->i_mode & S_IFMT) != (fattr->mode & S_IFMT)) - return -EIO; + return -ESTALE; if (!nfs_file_has_buffered_writers(nfsi)) { /* Verify a few of the more important attributes */ |