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NFSv4: It is not safe to dereference lsp->ls_state in release_lockowner

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It is quite possible for the release_lockowner RPC call to race with the
close RPC call, in which case, we cannot dereference lsp->ls_state in
order to find the nfs_server.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust
2012-03-19 16:17:18 -04:00
parent c4f1b62a4b
commit 5ae67c4fee
3 changed files with 7 additions and 7 deletions
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2
fs/nfs/nfs4_fs.h
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@@ -340,7 +340,7 @@ extern void nfs_increment_lock_seqid(int status, struct nfs_seqid *seqid);
extern void nfs_release_seqid(struct nfs_seqid *seqid); extern void nfs_release_seqid(struct nfs_seqid *seqid);
extern void nfs_free_seqid(struct nfs_seqid *seqid); extern void nfs_free_seqid(struct nfs_seqid *seqid);
extern void nfs4_free_lock_state(struct nfs4_lock_state *lsp); extern void nfs4_free_lock_state(struct nfs_server *server, struct nfs4_lock_state *lsp);
extern const nfs4_stateid zero_stateid; extern const nfs4_stateid zero_stateid;

4
fs/nfs/nfs4proc.c
View File

@@ -4760,13 +4760,14 @@ out:
struct nfs_release_lockowner_data { struct nfs_release_lockowner_data {
struct nfs4_lock_state *lsp; struct nfs4_lock_state *lsp;
struct nfs_server *server;
struct nfs_release_lockowner_args args; struct nfs_release_lockowner_args args;
}; };
static void nfs4_release_lockowner_release(void *calldata) static void nfs4_release_lockowner_release(void *calldata)
{ {
struct nfs_release_lockowner_data *data = calldata; struct nfs_release_lockowner_data *data = calldata;
nfs4_free_lock_state(data->lsp); nfs4_free_lock_state(data->server, data->lsp);
kfree(calldata); kfree(calldata);
} }
@@ -4788,6 +4789,7 @@ int nfs4_release_lockowner(struct nfs4_lock_state *lsp)
if (!data) if (!data)
return -ENOMEM; return -ENOMEM;
data->lsp = lsp; data->lsp = lsp;
data->server = server;
data->args.lock_owner.clientid = server->nfs_client->cl_clientid; data->args.lock_owner.clientid = server->nfs_client->cl_clientid;
data->args.lock_owner.id = lsp->ls_seqid.owner_id; data->args.lock_owner.id = lsp->ls_seqid.owner_id;
data->args.lock_owner.s_dev = server->s_dev; data->args.lock_owner.s_dev = server->s_dev;

8
fs/nfs/nfs4state.c
View File

@@ -791,10 +791,8 @@ out_free:
return NULL; return NULL;
} }
void nfs4_free_lock_state(struct nfs4_lock_state *lsp) void nfs4_free_lock_state(struct nfs_server *server, struct nfs4_lock_state *lsp)
{ {
struct nfs_server *server = lsp->ls_state->owner->so_server;
ida_simple_remove(&server->lockowner_id, lsp->ls_seqid.owner_id); ida_simple_remove(&server->lockowner_id, lsp->ls_seqid.owner_id);
nfs4_destroy_seqid_counter(&lsp->ls_seqid); nfs4_destroy_seqid_counter(&lsp->ls_seqid);
kfree(lsp); kfree(lsp);
@@ -828,7 +826,7 @@ static struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_
} }
spin_unlock(&state->state_lock); spin_unlock(&state->state_lock);
if (new != NULL) if (new != NULL)
nfs4_free_lock_state(new); nfs4_free_lock_state(state->owner->so_server, new);
return lsp; return lsp;
} }
@@ -853,7 +851,7 @@ void nfs4_put_lock_state(struct nfs4_lock_state *lsp)
if (nfs4_release_lockowner(lsp) == 0) if (nfs4_release_lockowner(lsp) == 0)
return; return;
} }
nfs4_free_lock_state(lsp); nfs4_free_lock_state(lsp->ls_state->owner->so_server, lsp);
} }
static void nfs4_fl_copy_lock(struct file_lock *dst, struct file_lock *src) static void nfs4_fl_copy_lock(struct file_lock *dst, struct file_lock *src)