NFSv4: Eliminate nfsv4 open race...
Make NFSv4 return the fully initialized file pointer with the
stateid that it created in the lookup w/intent.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 35da153..c9ecb81 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -47,6 +47,7 @@
#include <linux/nfs_page.h>
#include <linux/smp_lock.h>
#include <linux/namei.h>
+#include <linux/mount.h>
#include "nfs4_fs.h"
#include "delegation.h"
@@ -947,12 +948,26 @@
return status;
}
-struct inode *
+static void nfs4_intent_set_file(struct nameidata *nd, struct dentry *dentry, struct nfs4_state *state)
+{
+ struct file *filp;
+
+ filp = lookup_instantiate_filp(nd, dentry, NULL);
+ if (!IS_ERR(filp)) {
+ struct nfs_open_context *ctx;
+ ctx = (struct nfs_open_context *)filp->private_data;
+ ctx->state = state;
+ } else
+ nfs4_close_state(state, nd->intent.open.flags);
+}
+
+struct dentry *
nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
struct iattr attr;
struct rpc_cred *cred;
struct nfs4_state *state;
+ struct dentry *res;
if (nd->flags & LOOKUP_CREATE) {
attr.ia_mode = nd->intent.open.create_mode;
@@ -966,16 +981,23 @@
cred = rpcauth_lookupcred(NFS_SERVER(dir)->client->cl_auth, 0);
if (IS_ERR(cred))
- return (struct inode *)cred;
+ return (struct dentry *)cred;
state = nfs4_do_open(dir, dentry, nd->intent.open.flags, &attr, cred);
put_rpccred(cred);
- if (IS_ERR(state))
- return (struct inode *)state;
- return state->inode;
+ if (IS_ERR(state)) {
+ if (PTR_ERR(state) == -ENOENT)
+ d_add(dentry, NULL);
+ return (struct dentry *)state;
+ }
+ res = d_add_unique(dentry, state->inode);
+ if (res != NULL)
+ dentry = res;
+ nfs4_intent_set_file(nd, dentry, state);
+ return res;
}
int
-nfs4_open_revalidate(struct inode *dir, struct dentry *dentry, int openflags)
+nfs4_open_revalidate(struct inode *dir, struct dentry *dentry, int openflags, struct nameidata *nd)
{
struct rpc_cred *cred;
struct nfs4_state *state;
@@ -988,18 +1010,30 @@
if (IS_ERR(state))
state = nfs4_do_open(dir, dentry, openflags, NULL, cred);
put_rpccred(cred);
- if (state == ERR_PTR(-ENOENT) && dentry->d_inode == 0)
- return 1;
- if (IS_ERR(state))
- return 0;
+ if (IS_ERR(state)) {
+ switch (PTR_ERR(state)) {
+ case -EPERM:
+ case -EACCES:
+ case -EDQUOT:
+ case -ENOSPC:
+ case -EROFS:
+ lookup_instantiate_filp(nd, (struct dentry *)state, NULL);
+ return 1;
+ case -ENOENT:
+ if (dentry->d_inode == NULL)
+ return 1;
+ }
+ goto out_drop;
+ }
inode = state->inode;
+ iput(inode);
if (inode == dentry->d_inode) {
- iput(inode);
+ nfs4_intent_set_file(nd, dentry, state);
return 1;
}
- d_drop(dentry);
nfs4_close_state(state, openflags);
- iput(inode);
+out_drop:
+ d_drop(dentry);
return 0;
}
@@ -1500,7 +1534,7 @@
static int
nfs4_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
- int flags)
+ int flags, struct nameidata *nd)
{
struct nfs4_state *state;
struct rpc_cred *cred;
@@ -1522,13 +1556,13 @@
struct nfs_fattr fattr;
status = nfs4_do_setattr(NFS_SERVER(dir), &fattr,
NFS_FH(state->inode), sattr, state);
- if (status == 0) {
+ if (status == 0)
nfs_setattr_update_inode(state->inode, sattr);
- goto out;
- }
- } else if (flags != 0)
- goto out;
- nfs4_close_state(state, flags);
+ }
+ if (status == 0 && nd != NULL && (nd->flags & LOOKUP_OPEN))
+ nfs4_intent_set_file(nd, dentry, state);
+ else
+ nfs4_close_state(state, flags);
out:
return status;
}
@@ -2175,65 +2209,6 @@
return 0;
}
-/*
- * We will need to arrange for the VFS layer to provide an atomic open.
- * Until then, this open method is prone to inefficiency and race conditions
- * due to the lookup, potential create, and open VFS calls from sys_open()
- * placed on the wire.
- */
-static int
-nfs4_proc_file_open(struct inode *inode, struct file *filp)
-{
- struct dentry *dentry = filp->f_dentry;
- struct nfs_open_context *ctx;
- struct nfs4_state *state = NULL;
- struct rpc_cred *cred;
- int status = -ENOMEM;
-
- dprintk("nfs4_proc_file_open: starting on (%.*s/%.*s)\n",
- (int)dentry->d_parent->d_name.len,
- dentry->d_parent->d_name.name,
- (int)dentry->d_name.len, dentry->d_name.name);
-
-
- /* Find our open stateid */
- cred = rpcauth_lookupcred(NFS_SERVER(inode)->client->cl_auth, 0);
- if (IS_ERR(cred))
- return PTR_ERR(cred);
- ctx = alloc_nfs_open_context(dentry, cred);
- put_rpccred(cred);
- if (unlikely(ctx == NULL))
- return -ENOMEM;
- status = -EIO; /* ERACE actually */
- state = nfs4_find_state(inode, cred, filp->f_mode);
- if (unlikely(state == NULL))
- goto no_state;
- ctx->state = state;
- nfs4_close_state(state, filp->f_mode);
- ctx->mode = filp->f_mode;
- nfs_file_set_open_context(filp, ctx);
- put_nfs_open_context(ctx);
- if (filp->f_mode & FMODE_WRITE)
- nfs_begin_data_update(inode);
- return 0;
-no_state:
- printk(KERN_WARNING "NFS: v4 raced in function %s\n", __FUNCTION__);
- put_nfs_open_context(ctx);
- return status;
-}
-
-/*
- * Release our state
- */
-static int
-nfs4_proc_file_release(struct inode *inode, struct file *filp)
-{
- if (filp->f_mode & FMODE_WRITE)
- nfs_end_data_update(inode);
- nfs_file_clear_open_context(filp);
- return 0;
-}
-
static inline int nfs4_server_supports_acls(struct nfs_server *server)
{
return (server->caps & NFS_CAP_ACLS)
@@ -3145,8 +3120,8 @@
.read_setup = nfs4_proc_read_setup,
.write_setup = nfs4_proc_write_setup,
.commit_setup = nfs4_proc_commit_setup,
- .file_open = nfs4_proc_file_open,
- .file_release = nfs4_proc_file_release,
+ .file_open = nfs_open,
+ .file_release = nfs_release,
.lock = nfs4_proc_lock,
.clear_acl_cache = nfs4_zap_acl_attr,
};