Patch "nfsd4: fix leak of inode reference on delegation failure" has been added to the 3.10-stable tree

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This is a note to let you know that I've just added the patch titled

    nfsd4: fix leak of inode reference on delegation failure

to the 3.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfsd4-fix-leak-of-inode-reference-on-delegation-failure.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From bf7bd3e98be5c74813bee6ad496139fb0a011b3b Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
Date: Thu, 15 Aug 2013 16:55:26 -0400
Subject: nfsd4: fix leak of inode reference on delegation failure
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: "J. Bruce Fields" <bfields@xxxxxxxxxx>

commit bf7bd3e98be5c74813bee6ad496139fb0a011b3b upstream.

This fixes a regression from 68a3396178e6688ad7367202cdf0af8ed03c8727
"nfsd4: shut down more of delegation earlier".

After that commit, nfs4_set_delegation() failures result in
nfs4_put_delegation being called, but nfs4_put_delegation doesn't free
the nfs4_file that has already been set by alloc_init_deleg().

This can result in an oops on later unmounting the exported filesystem.

Note also delaying the fi_had_conflict check we're able to return a
better error (hence give 4.1 clients a better idea why the delegation
failed; though note CONFLICT isn't an exact match here, as that's
supposed to indicate a current conflict, but all we know here is that
there was one recently).

Reported-by: Toralf Förster <toralf.foerster@xxxxxx>
Tested-by: Toralf Förster <toralf.foerster@xxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
[tuomasjjrasanen: backported to 3.10
   Conflicts fs/nfsd/nfs4state.c:
     Delegation type flags have been removed from upstream code. In 3.10-series,
     they still exists and therefore the commit caused few conflicts in function
     signatures.
]
Signed-off-by: Tuomas Räsänen <tuomasjjrasanen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/nfsd/nfs4state.c |   31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -367,7 +367,6 @@ static struct nfs4_delegation *
 alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct svc_fh *current_fh, u32 type)
 {
 	struct nfs4_delegation *dp;
-	struct nfs4_file *fp = stp->st_file;
 
 	dprintk("NFSD alloc_init_deleg\n");
 	/*
@@ -377,8 +376,6 @@ alloc_init_deleg(struct nfs4_client *clp
 	 */
 	if (type != NFS4_OPEN_DELEGATE_READ)
 		return NULL;
-	if (fp->fi_had_conflict)
-		return NULL;
 	if (num_delegations > max_delegations)
 		return NULL;
 	dp = delegstateid(nfs4_alloc_stid(clp, deleg_slab));
@@ -395,8 +392,7 @@ alloc_init_deleg(struct nfs4_client *clp
 	INIT_LIST_HEAD(&dp->dl_perfile);
 	INIT_LIST_HEAD(&dp->dl_perclnt);
 	INIT_LIST_HEAD(&dp->dl_recall_lru);
-	get_nfs4_file(fp);
-	dp->dl_file = fp;
+	dp->dl_file = NULL;
 	dp->dl_type = type;
 	fh_copy_shallow(&dp->dl_fh, &current_fh->fh_handle);
 	dp->dl_time = 0;
@@ -2965,22 +2961,35 @@ static int nfs4_setlease(struct nfs4_del
 	return 0;
 }
 
-static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag)
+static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag, struct nfs4_file *fp)
 {
-	struct nfs4_file *fp = dp->dl_file;
+	int status;
 
-	if (!fp->fi_lease)
-		return nfs4_setlease(dp, flag);
+	if (fp->fi_had_conflict)
+		return -EAGAIN;
+	get_nfs4_file(fp);
+	dp->dl_file = fp;
+	if (!fp->fi_lease) {
+		status = nfs4_setlease(dp, flag);
+		if (status)
+			goto out_free;
+		return 0;
+	}
 	spin_lock(&recall_lock);
 	if (fp->fi_had_conflict) {
 		spin_unlock(&recall_lock);
-		return -EAGAIN;
+		status = -EAGAIN;
+		goto out_free;
 	}
 	atomic_inc(&fp->fi_delegees);
 	list_add(&dp->dl_perfile, &fp->fi_delegations);
 	spin_unlock(&recall_lock);
 	list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations);
 	return 0;
+out_free:
+	put_nfs4_file(fp);
+	dp->dl_file = fp;
+	return status;
 }
 
 static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
@@ -3046,7 +3055,7 @@ nfs4_open_delegation(struct net *net, st
 	dp = alloc_init_deleg(oo->oo_owner.so_client, stp, fh, flag);
 	if (dp == NULL)
 		goto out_no_deleg;
-	status = nfs4_set_delegation(dp, flag);
+	status = nfs4_set_delegation(dp, flag, stp->st_file);
 	if (status)
 		goto out_free;
 


Patches currently in stable-queue which might be from bfields@xxxxxxxxxx are

queue-3.10/nfsd4-fix-leak-of-inode-reference-on-delegation-failure.patch
queue-3.10/nfsd-fix-slot-wake-up-race-in-the-nfsv4.1-callback-code.patch
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