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author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2005-11-04 20:32:58 (GMT) |
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committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2005-11-04 20:32:58 (GMT) |
commit | 4cecb76ff86db46d2823550256c828b6597f418e (patch) | |
tree | db80c6f4423d2559661234e8d1cd34b2c15f7750 /fs/nfs/nfs4state.c | |
parent | 462aae65f6ea41de05ebc2a54a9e6b95563591f3 (diff) | |
download | linux-fsl-qoriq-4cecb76ff86db46d2823550256c828b6597f418e.tar.xz |
NFSv4: Fix a race between open() and close()
We must not remove the nfs4_state structure from the inode open lists
before we are in sequence lock.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/nfs4state.c')
-rw-r--r-- | fs/nfs/nfs4state.c | 58 |
1 files changed, 30 insertions, 28 deletions
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index 2d5a6a2..959374d 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -366,6 +366,23 @@ nfs4_alloc_open_state(void) return state; } +void +nfs4_state_set_mode_locked(struct nfs4_state *state, mode_t mode) +{ + if (state->state == mode) + return; + /* NB! List reordering - see the reclaim code for why. */ + if ((mode & FMODE_WRITE) != (state->state & FMODE_WRITE)) { + if (mode & FMODE_WRITE) + list_move(&state->open_states, &state->owner->so_states); + else + list_move_tail(&state->open_states, &state->owner->so_states); + } + if (mode == 0) + list_del_init(&state->inode_states); + state->state = mode; +} + static struct nfs4_state * __nfs4_find_state(struct inode *inode, struct rpc_cred *cred, mode_t mode) { @@ -376,10 +393,6 @@ __nfs4_find_state(struct inode *inode, struct rpc_cred *cred, mode_t mode) list_for_each_entry(state, &nfsi->open_states, inode_states) { if (state->owner->so_cred != cred) continue; - if ((mode & FMODE_READ) != 0 && state->nreaders == 0) - continue; - if ((mode & FMODE_WRITE) != 0 && state->nwriters == 0) - continue; if ((state->state & mode) != mode) continue; atomic_inc(&state->count); @@ -400,7 +413,7 @@ __nfs4_find_state_byowner(struct inode *inode, struct nfs4_state_owner *owner) list_for_each_entry(state, &nfsi->open_states, inode_states) { /* Is this in the process of being freed? */ - if (state->nreaders == 0 && state->nwriters == 0) + if (state->state == 0) continue; if (state->owner == owner) { atomic_inc(&state->count); @@ -481,7 +494,6 @@ void nfs4_put_open_state(struct nfs4_state *state) spin_unlock(&inode->i_lock); spin_unlock(&owner->so_lock); iput(inode); - BUG_ON (state->state != 0); nfs4_free_open_state(state); nfs4_put_state_owner(owner); } @@ -493,7 +505,7 @@ void nfs4_close_state(struct nfs4_state *state, mode_t mode) { struct inode *inode = state->inode; struct nfs4_state_owner *owner = state->owner; - int newstate; + int oldstate, newstate = 0; atomic_inc(&owner->so_count); /* Protect against nfs4_find_state() */ @@ -503,30 +515,20 @@ void nfs4_close_state(struct nfs4_state *state, mode_t mode) state->nreaders--; if (mode & FMODE_WRITE) state->nwriters--; - if (state->nwriters == 0) { - if (state->nreaders == 0) - list_del_init(&state->inode_states); - /* See reclaim code */ - list_move_tail(&state->open_states, &owner->so_states); + oldstate = newstate = state->state; + if (state->nreaders == 0) + newstate &= ~FMODE_READ; + if (state->nwriters == 0) + newstate &= ~FMODE_WRITE; + if (test_bit(NFS_DELEGATED_STATE, &state->flags)) { + nfs4_state_set_mode_locked(state, newstate); + oldstate = newstate; } spin_unlock(&inode->i_lock); spin_unlock(&owner->so_lock); - newstate = 0; - if (state->state != 0) { - if (state->nreaders) - newstate |= FMODE_READ; - if (state->nwriters) - newstate |= FMODE_WRITE; - if (state->state == newstate) - goto out; - if (test_bit(NFS_DELEGATED_STATE, &state->flags)) { - state->state = newstate; - goto out; - } - if (nfs4_do_close(inode, state, newstate) == 0) - return; - } -out: + + if (oldstate != newstate && nfs4_do_close(inode, state) == 0) + return; nfs4_put_open_state(state); nfs4_put_state_owner(owner); } |