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NFSv4: Fix a race when updating an open_stateid

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If we're replacing an old stateid which has a different 'other' field,
then we probably need to free the old stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Trond Myklebust 2016-09-22 13:39:13 -04:00 committed by Anna Schumaker
parent b1a318de9b
commit 1393d9612b
1 changed files with 26 additions and 9 deletions
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35
fs/nfs/nfs4proc.c
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@ -1399,11 +1399,12 @@ static void nfs_test_and_clear_all_open_stateid(struct nfs4_state *state)
}
static bool nfs_need_update_open_stateid(struct nfs4_state *state,
nfs4_stateid *stateid)
const nfs4_stateid *stateid, nfs4_stateid *freeme)
{
if (test_and_set_bit(NFS_OPEN_STATE, &state->flags) == 0)
return true;
if (!nfs4_stateid_match_other(stateid, &state->open_stateid)) {
nfs4_stateid_copy(freeme, &state->open_stateid);
nfs_test_and_clear_all_open_stateid(state);
return true;
}
@ -1467,7 +1468,9 @@ static void nfs_clear_open_stateid(struct nfs4_state *state,
nfs4_schedule_state_manager(state->owner->so_server->nfs_client);
}
static void nfs_set_open_stateid_locked(struct nfs4_state *state, nfs4_stateid *stateid, fmode_t fmode)
static void nfs_set_open_stateid_locked(struct nfs4_state *state,
const nfs4_stateid *stateid, fmode_t fmode,
nfs4_stateid *freeme)
{
switch (fmode) {
case FMODE_READ:
@ -1479,14 +1482,18 @@ 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))
if (!nfs_need_update_open_stateid(state, stateid, freeme))
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 __update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_stateid, const nfs4_stateid *deleg_stateid, fmode_t fmode)
static void __update_open_stateid(struct nfs4_state *state,
const nfs4_stateid *open_stateid,
const nfs4_stateid *deleg_stateid,
fmode_t fmode,
nfs4_stateid *freeme)
{
/*
* Protect the call to nfs4_state_set_mode_locked and
@ -1499,16 +1506,22 @@ static void __update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_s
set_bit(NFS_DELEGATED_STATE, &state->flags);
}
if (open_stateid != NULL)
nfs_set_open_stateid_locked(state, open_stateid, fmode);
nfs_set_open_stateid_locked(state, open_stateid, fmode, freeme);
write_sequnlock(&state->seqlock);
update_open_stateflags(state, fmode);
spin_unlock(&state->owner->so_lock);
}
static int update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_stateid, nfs4_stateid *delegation, fmode_t fmode)
static int update_open_stateid(struct nfs4_state *state,
const nfs4_stateid *open_stateid,
const nfs4_stateid *delegation,
fmode_t fmode)
{
struct nfs_server *server = NFS_SERVER(state->inode);
struct nfs_client *clp = server->nfs_client;
struct nfs_inode *nfsi = NFS_I(state->inode);
struct nfs_delegation *deleg_cur;
nfs4_stateid freeme = {0};
int ret = 0;
fmode &= (FMODE_READ|FMODE_WRITE);
@ -1530,7 +1543,8 @@ static int update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_stat
goto no_delegation_unlock;
nfs_mark_delegation_referenced(deleg_cur);
__update_open_stateid(state, open_stateid, &deleg_cur->stateid, fmode);
__update_open_stateid(state, open_stateid, &deleg_cur->stateid,
fmode, &freeme);
ret = 1;
no_delegation_unlock:
spin_unlock(&deleg_cur->lock);
@ -1538,11 +1552,14 @@ no_delegation:
rcu_read_unlock();
if (!ret && open_stateid != NULL) {
__update_open_stateid(state, open_stateid, NULL, fmode);
__update_open_stateid(state, open_stateid, NULL, fmode, &freeme);
ret = 1;
}
if (test_bit(NFS_STATE_RECLAIM_NOGRACE, &state->flags))
nfs4_schedule_state_manager(state->owner->so_server->nfs_client);
nfs4_schedule_state_manager(clp);
if (freeme.type != 0)
nfs4_test_and_free_stateid(server, &freeme,
state->owner->so_cred);
return ret;
}