This is a note to let you know that I've just added the patch titled
NFSv4: Fix a potential state reclaim deadlock
to the 6.0-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:
nfsv4-fix-a-potential-state-reclaim-deadlock.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1dd18ffadea024c4b5f8d4151827a9d044b1c9d8
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Sun Oct 16 14:44:31 2022 -0400
NFSv4: Fix a potential state reclaim deadlock
[ Upstream commit 1ba04394e028ea8b45d92685cc0d6ab582cf7647 ]
If the server reboots while we are engaged in a delegation return, and
there is a pNFS layout with return-on-close set, then the current code
can end up deadlocking in pnfs_roc() when nfs_inode_set_delegation()
tries to return the old delegation.
Now that delegreturn actually uses its own copy of the stateid, it
should be safe to just always update the delegation stateid in place.
Fixes: 078000d02d57 ("pNFS: We want return-on-close to complete when evicting the inode")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 5c97cad741a7..ead8a0e06abf 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -228,8 +228,7 @@ static int nfs_delegation_claim_opens(struct inode *inode,
*
*/
void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
- fmode_t type,
- const nfs4_stateid *stateid,
+ fmode_t type, const nfs4_stateid *stateid,
unsigned long pagemod_limit)
{
struct nfs_delegation *delegation;
@@ -239,25 +238,24 @@ void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
delegation = rcu_dereference(NFS_I(inode)->delegation);
if (delegation != NULL) {
spin_lock(&delegation->lock);
- if (nfs4_is_valid_delegation(delegation, 0)) {
- nfs4_stateid_copy(&delegation->stateid, stateid);
- delegation->type = type;
- delegation->pagemod_limit = pagemod_limit;
- oldcred = delegation->cred;
- delegation->cred = get_cred(cred);
- clear_bit(NFS_DELEGATION_NEED_RECLAIM,
- &delegation->flags);
- spin_unlock(&delegation->lock);
- rcu_read_unlock();
- put_cred(oldcred);
- trace_nfs4_reclaim_delegation(inode, type);
- return;
- }
- /* We appear to have raced with a delegation return. */
+ nfs4_stateid_copy(&delegation->stateid, stateid);
+ delegation->type = type;
+ delegation->pagemod_limit = pagemod_limit;
+ oldcred = delegation->cred;
+ delegation->cred = get_cred(cred);
+ clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
+ if (test_and_clear_bit(NFS_DELEGATION_REVOKED,
+ &delegation->flags))
+ atomic_long_inc(&nfs_active_delegations);
spin_unlock(&delegation->lock);
+ rcu_read_unlock();
+ put_cred(oldcred);
+ trace_nfs4_reclaim_delegation(inode, type);
+ } else {
+ rcu_read_unlock();
+ nfs_inode_set_delegation(inode, cred, type, stateid,
+ pagemod_limit);
}
- rcu_read_unlock();
- nfs_inode_set_delegation(inode, cred, type, stateid, pagemod_limit);
}
static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
