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When creating a node, do the server-dance before creating the local 

data structure.  This avoids a race between create and lookup, as
the kernel now unlock the directory before the create operation
returns.
This commit is contained in:
pooka 2007-12-09 18:05:42 +00:00
parent 3c4a86f736
commit faa30930fd
1 changed files with 58 additions and 38 deletions
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96
usr.sbin/puffs/mount_psshfs/node.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: node.c,v 1.52 2007/12/07 14:59:22 pooka Exp $ */
/* $NetBSD: node.c,v 1.53 2007/12/09 18:05:42 pooka Exp $ */
/*
* Copyright (c) 2006 Antti Kantee. All Rights Reserved.
@ -27,7 +27,7 @@
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: node.c,v 1.52 2007/12/07 14:59:22 pooka Exp $");
__RCSID("$NetBSD: node.c,v 1.53 2007/12/09 18:05:42 pooka Exp $");
#endif /* !lint */
#include <assert.h>
@ -159,8 +159,9 @@ psshfs_node_setattr(struct puffs_usermount *pu, void *opc,
}
int
psshfs_node_create(struct puffs_usermount *pu, void *opc, struct puffs_newinfo *pni,
const struct puffs_cn *pcn, const struct vattr *va)
psshfs_node_create(struct puffs_usermount *pu, void *opc,
struct puffs_newinfo *pni, const struct puffs_cn *pcn,
const struct vattr *va)
{
PSSHFSAUTOVAR(pu);
struct puffs_node *pn = opc;
@ -168,29 +169,40 @@ psshfs_node_create(struct puffs_usermount *pu, void *opc, struct puffs_newinfo *
char *fhand = NULL;
uint32_t fhandlen;
pn_new = allocnode(pu, pn, pcn->pcn_name, va);
if (!pn_new) {
rv = ENOMEM;
goto out;
}
/* Create node on server first */
psbuf_req_str(pb, SSH_FXP_OPEN, reqid, PCNPATH(pcn));
psbuf_put_4(pb, SSH_FXF_WRITE | SSH_FXF_CREAT | SSH_FXF_TRUNC);
psbuf_put_vattr(pb, va);
GETRESPONSE(pb);
rv = psbuf_expect_handle(pb, &fhand, &fhandlen);
if (rv == 0)
puffs_newinfo_setcookie(pni, pn_new);
else
if (rv)
goto out;
/*
* Do *not* create the local node before getting a response
* from the server. Otherwise we might screw up consistency,
* namely that the node can be looked up before create has
* returned (mind you, the kernel will unlock the directory
* before the create call from userspace returns).
*/
pn_new = allocnode(pu, pn, pcn->pcn_name, va);
if (!pn_new) {
struct puffs_framebuf *pb2 = psbuf_makeout();
reqid = NEXTREQ(pctx);
psbuf_req_str(pb2, SSH_FXP_REMOVE, reqid, PCNPATH(pcn));
JUSTSEND(pb2);
rv = ENOMEM;
}
if (pn_new)
puffs_newinfo_setcookie(pni, pn_new);
reqid = NEXTREQ(pctx);
psbuf_recycleout(pb);
psbuf_req_data(pb, SSH_FXP_CLOSE, reqid, fhand, fhandlen);
JUSTSEND(pb);
free(fhand);
return 0;
return rv;
out:
free(fhand);
@ -692,38 +704,42 @@ psshfs_node_rmdir(struct puffs_usermount *pu, void *opc, void *targ,
}
int
psshfs_node_mkdir(struct puffs_usermount *pu, void *opc, struct puffs_newinfo *pni,
const struct puffs_cn *pcn, const struct vattr *va)
psshfs_node_mkdir(struct puffs_usermount *pu, void *opc,
struct puffs_newinfo *pni, const struct puffs_cn *pcn,
const struct vattr *va)
{
PSSHFSAUTOVAR(pu);
struct puffs_node *pn = opc;
struct puffs_node *pn_new;
pn_new = allocnode(pu, pn, pcn->pcn_name, va);
if (!pn_new) {
rv = ENOMEM;
goto out;
}
psbuf_req_str(pb, SSH_FXP_MKDIR, reqid, PCNPATH(pcn));
psbuf_put_vattr(pb, va);
GETRESPONSE(pb);
rv = psbuf_expect_status(pb);
if (rv)
goto out;
if (rv == 0)
pn_new = allocnode(pu, pn, pcn->pcn_name, va);
if (pn_new) {
puffs_newinfo_setcookie(pni, pn_new);
else
nukenode(pn_new, pcn->pcn_name, 1);
} else {
struct puffs_framebuf *pb2 = psbuf_makeout();
reqid = NEXTREQ(pctx);
psbuf_recycleout(pb2);
psbuf_req_str(pb2, SSH_FXP_RMDIR, reqid, PCNPATH(pcn));
JUSTSEND(pb2);
rv = ENOMEM;
}
out:
PSSHFSRETURN(rv);
}
int
psshfs_node_symlink(struct puffs_usermount *pu, void *opc, struct puffs_newinfo *pni,
const struct puffs_cn *pcn, const struct vattr *va,
const char *link_target)
psshfs_node_symlink(struct puffs_usermount *pu, void *opc,
struct puffs_newinfo *pni, const struct puffs_cn *pcn,
const struct vattr *va, const char *link_target)
{
PSSHFSAUTOVAR(pu);
struct puffs_node *pn = opc;
@ -734,12 +750,6 @@ psshfs_node_symlink(struct puffs_usermount *pu, void *opc, struct puffs_newinfo
goto out;
}
pn_new = allocnode(pu, pn, pcn->pcn_name, va);
if (!pn_new) {
rv = ENOMEM;
goto out;
}
/*
* XXX: ietf says: source, target. openssh says: ietf who?
* Let's go with openssh and build quirk tables later if we care
@ -749,10 +759,20 @@ psshfs_node_symlink(struct puffs_usermount *pu, void *opc, struct puffs_newinfo
GETRESPONSE(pb);
rv = psbuf_expect_status(pb);
if (rv == 0)
if (rv)
goto out;
pn_new = allocnode(pu, pn, pcn->pcn_name, va);
if (pn_new) {
puffs_newinfo_setcookie(pni, pn_new);
else
nukenode(pn_new, pcn->pcn_name, 1);
} else {
struct puffs_framebuf *pb2 = psbuf_makeout();
reqid = NEXTREQ(pctx);
psbuf_recycleout(pb2);
psbuf_req_str(pb2, SSH_FXP_REMOVE, reqid, PCNPATH(pcn));
JUSTSEND(pb2);
rv = ENOMEM;
}
out:
PSSHFSRETURN(rv);