[PATCH 1/2] NFS: Remove bad delegations during open recovery

[PATCH 1/2] NFS: Remove bad delegations during open recovery

[bjschuma]

From: Bryan Schumaker <bjschuma@netapp.com>

I put the client into an open recovery loop by:
	Client: Open file
		read half
	Server: Expire client (echo 0 > /sys/kernel/debug/nfsd/forget_clients)
	Client: Drop vm cache (echo 3 > /proc/sys/vm/drop_caches)
		finish reading file

This causes a loop because the client never updates the nfs4_state after
discovering that the delegation is invalid.  This means it will keep
trying to read using the bad delegation rather than attempting to re-open
the file.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
---
 fs/nfs/nfs4proc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 1e50326..e47ec55 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1774,7 +1774,9 @@ static void nfs41_clear_delegation_stateid(struct nfs4_state *state)
 		 * informs us the stateid is unrecognized. */
 		if (status != -NFS4ERR_BAD_STATEID)
 			nfs41_free_stateid(server, stateid);
+		nfs_remove_bad_delegation(state->inode);
 
+		nfs4_stateid_copy(&state->stateid, &state->open_stateid);
 		clear_bit(NFS_DELEGATED_STATE, &state->flags);
 	}
 }
-- 
1.7.12.1

[PATCH 2/2] NFS: Always use the open stateid when checking for expired opens

[bjschuma]

From: Bryan Schumaker <bjschuma@netapp.com>

If we are reading through a delegation, and the delegation is OK then
state->stateid will still point to a delegation stateid and not an open
stateid.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
---
 fs/nfs/nfs4proc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e47ec55..df7e1a3 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1792,7 +1792,7 @@ static void nfs41_clear_delegation_stateid(struct nfs4_state *state)
 static int nfs41_check_open_stateid(struct nfs4_state *state)
 {
 	struct nfs_server *server = NFS_SERVER(state->inode);
-	nfs4_stateid *stateid = &state->stateid;
+	nfs4_stateid *stateid = &state->open_stateid;
 	int status;
 
 	/* If a state reset has been done, test_stateid is unneeded */
-- 
1.7.12.1

Re: [PATCH 1/2] NFS: Remove bad delegations during open recovery

[Myklebust, Trond]

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