NFSv4: Don't update the open stateid unless it is newer than the old one

This patch is in preparation for the NFSv4.1 parallel open capability.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index a5b27c2d9689f86704857b55365347e2f5c515d6..df81fcc138a7b38ca968feef6d7088434df70f4d 100644 (file)
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -500,6 +500,16 @@ static inline bool nfs4_stateid_match(const nfs4_stateid *dst, const nfs4_statei
        return memcmp(dst, src, sizeof(*dst)) == 0;
 }
 
+static inline bool nfs4_stateid_match_other(const nfs4_stateid *dst, const nfs4_stateid *src)
+{
+       return memcmp(dst->other, src->other, NFS4_STATEID_OTHER_SIZE) == 0;
+}
+
+static inline bool nfs4_stateid_is_newer(const nfs4_stateid *s1, const nfs4_stateid *s2)
+{
+       return (s32)(be32_to_cpu(s1->seqid) - be32_to_cpu(s2->seqid)) > 0;
+}
+
 static inline bool nfs4_valid_open_stateid(const struct nfs4_state *state)
 {
        return test_bit(NFS_STATE_RECOVERY_FAILED, &state->flags) == 0;

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 2da6a698b8f7719c14eefec65e6148a48d030bb3..96e0bd42f38c0e588a4e0443fb9dfdf218e55127 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1137,12 +1137,20 @@ static void update_open_stateflags(struct nfs4_state *state, fmode_t fmode)
        nfs4_state_set_mode_locked(state, state->state | fmode);
 }
 
+static bool nfs_need_update_open_stateid(struct nfs4_state *state,
+               nfs4_stateid *stateid)
+{
+       if (test_and_set_bit(NFS_OPEN_STATE, &state->flags) == 0)
+               return true;
+       if (!nfs4_stateid_match_other(stateid, &state->open_stateid))
+               return true;
+       if (nfs4_stateid_is_newer(stateid, &state->open_stateid))
+               return true;
+       return false;
+}
+
 static void nfs_set_open_stateid_locked(struct nfs4_state *state, nfs4_stateid *stateid, fmode_t fmode)
 {
-       if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
-               nfs4_stateid_copy(&state->stateid, stateid);
-       nfs4_stateid_copy(&state->open_stateid, stateid);
-       set_bit(NFS_OPEN_STATE, &state->flags);
        switch (fmode) {
                case FMODE_READ:
                        set_bit(NFS_O_RDONLY_STATE, &state->flags);
@@ -1153,6 +1161,11 @@ static void nfs_set_open_stateid_locked(struct nfs4_state *state, nfs4_stateid *
                case FMODE_READ|FMODE_WRITE:
                        set_bit(NFS_O_RDWR_STATE, &state->flags);
        }
+       if (!nfs_need_update_open_stateid(state, stateid))
+               return;
+       if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
+               nfs4_stateid_copy(&state->stateid, stateid);
+       nfs4_stateid_copy(&state->open_stateid, stateid);
 }
 
 static void nfs_set_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid, fmode_t fmode)