Messages in this thread Patch in this message | | | Subject | Re: nfsfh.c:nfsd_findparent lookup("..") failure fix in 2.4.4 - xfs related? | From | Trond Myklebust <> | Date | 18 Oct 2001 12:42:01 +0200 |
| |
>>>>> " " == Peter Wächtler <pwaechtler@loewe-komp.de> writes:
> The following diff was made in 2.4.4. diff -u --recursive > --new-file v2.4.4/linux/fs/nfsd/nfsfh.c linux/fs/nfsd/nfsfh.c > --- v2.4.4/linux/fs/nfsd/nfsfh.c Fri Feb 9 11:29:44 2001 > +++ linux/fs/nfsd/nfsfh.c Sat May 19 17:47:55 2001 > @@ -244,6 +245,11 @@ > */ > pdentry = child->d_inode->i_op->lookup(child->d_inode, > tdentry); d_drop(tdentry); /* we never want ".." hashed > */ > + if (!pdentry && tdentry->d_inode == NULL) { > + /* File system cannot find ".." ... sad but possible */ > + dput(tdentry); > + pdentry = ERR_PTR(-EINVAL); > + }
> Umh. How is it possible to have a valid dentry which has no > parent? Even "/.." is linked to "/." Who said these are *valid* dentries?
There's no way you can fit full path information into an NFS filehandle, so when the client passes such an object to nfsd, the latter sometimes has to make so-called 'disconnected' dentries. These are dentries which contain no path information, and are basically just providing a dentry alias for the inode.
The code you are looking at attempts to call the filesystem in order to lookup a file named '..' from just such a disconnected dentry. The purpose being to actually recreate the path, and hence convert the dentry into a valid one...
Cheers, Trond - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |