From: Trond Myklebust <trond.myklebust@fys.uio.no>
NFSv4: Atomic open(). Fixes races w.r.t. opening files.
---
fs/nfs/dir.c | 138 +++++++++++++++++++++++++++++++++++++++++++++++-
fs/nfs/inode.c | 54 +++++++++++++++++-
fs/nfs/nfs3proc.c | 2
fs/nfs/nfs4proc.c | 134 +++++++++++++++++++++++++++++++++-------------
fs/nfs/nfs4state.c | 2
fs/nfs/proc.c | 2
include/linux/nfs_fs.h | 6 ++
include/linux/nfs_xdr.h | 2
8 files changed, 295 insertions(+), 45 deletions(-)
diff -puN fs/nfs/dir.c~nfs-27-atomic_open fs/nfs/dir.c
--- 25/fs/nfs/dir.c~nfs-27-atomic_open 2004-01-14 02:09:59.000000000 -0800
+++ 25-akpm/fs/nfs/dir.c 2004-01-14 02:10:00.000000000 -0800
@@ -72,6 +72,26 @@ struct inode_operations nfs_dir_inode_op
.setattr = nfs_setattr,
};
+#ifdef CONFIG_NFS_V4
+
+static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *);
+struct inode_operations nfs4_dir_inode_operations = {
+ .create = nfs_create,
+ .lookup = nfs_atomic_lookup,
+ .link = nfs_link,
+ .unlink = nfs_unlink,
+ .symlink = nfs_symlink,
+ .mkdir = nfs_mkdir,
+ .rmdir = nfs_rmdir,
+ .mknod = nfs_mknod,
+ .rename = nfs_rename,
+ .permission = nfs_permission,
+ .getattr = nfs_getattr,
+ .setattr = nfs_setattr,
+};
+
+#endif /* CONFIG_NFS_V4 */
+
/*
* Open file
*/
@@ -670,7 +690,7 @@ static struct dentry *nfs_lookup(struct
goto out;
error = -ENOMEM;
- dentry->d_op = &nfs_dentry_operations;
+ dentry->d_op = NFS_PROTO(dir)->dentry_ops;
lock_kernel();
@@ -702,6 +722,119 @@ out:
return ERR_PTR(error);
}
+#ifdef CONFIG_NFS_V4
+static int nfs_open_revalidate(struct dentry *, struct nameidata *);
+
+struct dentry_operations nfs4_dentry_operations = {
+ .d_revalidate = nfs_open_revalidate,
+ .d_delete = nfs_dentry_delete,
+ .d_iput = nfs_dentry_iput,
+};
+
+static int is_atomic_open(struct inode *dir, struct nameidata *nd)
+{
+ if (!nd)
+ return 0;
+ /* Check that we are indeed trying to open this file */
+ if ((nd->flags & LOOKUP_CONTINUE) || !(nd->flags & LOOKUP_OPEN))
+ return 0;
+ /* NFS does not (yet) have a stateful open for directories */
+ if (nd->flags & LOOKUP_DIRECTORY)
+ return 0;
+ /* Are we trying to write to a read only partition? */
+ if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE)))
+ return 0;
+ return 1;
+}
+
+static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
+{
+ struct inode *inode = NULL;
+ int error = 0;
+
+ /* Check that we are indeed trying to open this file */
+ if (!is_atomic_open(dir, nd))
+ goto no_open;
+
+ if (dentry->d_name.len > NFS_SERVER(dir)->namelen) {
+ error = -ENAMETOOLONG;
+ goto out;
+ }
+ dentry->d_op = NFS_PROTO(dir)->dentry_ops;
+
+ /* Let vfs_create() deal with O_EXCL */
+ if (nd->intent.open.flags & O_EXCL)
+ goto no_entry;
+
+ /* Open the file on the server */
+ lock_kernel();
+ inode = nfs4_atomic_open(dir, dentry, nd);
+ unlock_kernel();
+ if (IS_ERR(inode)) {
+ error = PTR_ERR(inode);
+ switch (error) {
+ /* Make a negative dentry */
+ case -ENOENT:
+ inode = NULL;
+ break;
+ /* This turned out not to be a regular file */
+ case -ELOOP:
+ if (!(nd->intent.open.flags & O_NOFOLLOW))
+ goto no_open;
+ /* case -EISDIR: */
+ /* case -EINVAL: */
+ default:
+ goto out;
+ }
+ }
+no_entry:
+ d_add(dentry, inode);
+ nfs_renew_times(dentry);
+out:
+ BUG_ON(error > 0);
+ return ERR_PTR(error);
+no_open:
+ return nfs_lookup(dir, dentry, nd);
+}
+
+static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+ struct dentry *parent = NULL;
+ struct inode *inode = dentry->d_inode;
+ int openflags, ret = 0;
+
+ /* NFS only supports OPEN for regular files */
+ if (inode && !S_ISREG(inode->i_mode))
+ goto no_open;
+ parent = dget_parent(dentry);
+ if (!is_atomic_open(parent->d_inode, nd))
+ goto no_open;
+ openflags = nd->intent.open.flags;
+ if (openflags & O_CREAT) {
+ /* If this is a negative dentry, just drop it */
+ if (!inode)
+ goto out;
+ /* If this is exclusive open, just revalidate */
+ if (openflags & O_EXCL)
+ goto no_open;
+ }
+ /* We can't create new files, or truncate existing ones here */
+ openflags &= ~(O_CREAT|O_TRUNC);
+
+ lock_kernel();
+ ret = nfs4_open_revalidate(parent->d_inode, dentry, openflags);
+ unlock_kernel();
+out:
+ dput(parent);
+ if (!ret)
+ d_drop(dentry);
+ return ret;
+no_open:
+ dput(parent);
+ return nfs_lookup_revalidate(dentry, nd);
+}
+#endif /* CONFIG_NFSV4 */
+
static inline
int find_dirent_name(nfs_readdir_descriptor_t *desc, struct page *page, struct dentry *dentry)
{
@@ -1306,6 +1439,9 @@ nfs_permission(struct inode *inode, int
/* We only need to check permissions on file open() and access() */
if (!nd || !(nd->flags & (LOOKUP_OPEN|LOOKUP_ACCESS)))
return 0;
+ /* NFSv4 has atomic_open... */
+ if (NFS_PROTO(inode)->version > 3 && (nd->flags & LOOKUP_OPEN))
+ return 0;
}
lock_kernel();
diff -puN fs/nfs/inode.c~nfs-27-atomic_open fs/nfs/inode.c
--- 25/fs/nfs/inode.c~nfs-27-atomic_open 2004-01-14 02:10:00.000000000 -0800
+++ 25-akpm/fs/nfs/inode.c 2004-01-14 02:10:00.000000000 -0800
@@ -303,7 +303,6 @@ nfs_sb_init(struct super_block *sb, rpc_
server = NFS_SB(sb);
sb->s_magic = NFS_SUPER_MAGIC;
- sb->s_op = &nfs_sops;
/* Did getting the root inode fail? */
if (nfs_get_root(&root_inode, authflavor, sb, &server->fh) < 0)
@@ -312,7 +311,7 @@ nfs_sb_init(struct super_block *sb, rpc_
if (!sb->s_root)
goto out_no_root;
- sb->s_root->d_op = &nfs_dentry_operations;
+ sb->s_root->d_op = server->rpc_ops->dentry_ops;
/* Get some general file system info */
if (server->rpc_ops->fsinfo(server, &server->fh, &fsinfo) < 0) {
@@ -513,6 +512,7 @@ nfs_fill_super(struct super_block *sb, s
goto out_shutdown;
}
+ sb->s_op = &nfs_sops;
err = nfs_sb_init(sb, authflavor);
if (err != 0)
goto out_noinit;
@@ -745,7 +745,7 @@ nfs_fhget(struct super_block *sb, struct
inode->i_data.a_ops = &nfs_file_aops;
inode->i_data.backing_dev_info = &NFS_SB(sb)->backing_dev_info;
} else if (S_ISDIR(inode->i_mode)) {
- inode->i_op = &nfs_dir_inode_operations;
+ inode->i_op = NFS_SB(sb)->rpc_ops->dir_inode_ops;
inode->i_fop = &nfs_dir_operations;
if (nfs_server_capable(inode, NFS_CAP_READDIRPLUS)
&& fattr->size <= NFS_LIMIT_READDIRPLUS)
@@ -837,7 +837,12 @@ printk("nfs_setattr: revalidate failed,
filemap_fdatawait(inode->i_mapping);
if (error)
goto out;
+ /* Optimize away unnecessary truncates */
+ if ((attr->ia_valid & ATTR_SIZE) && i_size_read(inode) == attr->ia_size)
+ attr->ia_valid &= ~ATTR_SIZE;
}
+ if (!attr->ia_valid)
+ goto out;
error = NFS_PROTO(inode)->setattr(dentry, &fattr, attr);
if (error)
@@ -1357,6 +1362,48 @@ static struct file_system_type nfs_fs_ty
#ifdef CONFIG_NFS_V4
+static void nfs4_clear_inode(struct inode *);
+
+static struct super_operations nfs4_sops = {
+ .alloc_inode = nfs_alloc_inode,
+ .destroy_inode = nfs_destroy_inode,
+ .write_inode = nfs_write_inode,
+ .delete_inode = nfs_delete_inode,
+ .put_super = nfs_put_super,
+ .statfs = nfs_statfs,
+ .clear_inode = nfs4_clear_inode,
+ .umount_begin = nfs_umount_begin,
+ .show_options = nfs_show_options,
+};
+
+/*
+ * Clean out any remaining NFSv4 state that might be left over due
+ * to open() calls that passed nfs_atomic_lookup, but failed to call
+ * nfs_open().
+ */
+static void nfs4_clear_inode(struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ while (!list_empty(&nfsi->open_states)) {
+ struct nfs4_state *state;
+
+ state = list_entry(nfsi->open_states.next,
+ struct nfs4_state,
+ inode_states);
+ dprintk("%s(%s/%Ld): found unclaimed NFSv4 state %p\n",
+ __FUNCTION__,
+ inode->i_sb->s_id,
+ (long long)NFS_FILEID(inode),
+ state);
+ list_del(&state->inode_states);
+ nfs4_put_open_state(state);
+ }
+ /* Now call standard NFS clear_inode() code */
+ nfs_clear_inode(inode);
+}
+
+
static int nfs4_fill_super(struct super_block *sb, struct nfs4_mount_data *data, int silent)
{
struct nfs_server *server;
@@ -1481,6 +1528,7 @@ static int nfs4_fill_super(struct super_
if ((server->idmap = nfs_idmap_new(server)) == NULL)
printk(KERN_WARNING "NFS: couldn't start IDmap\n");
+ sb->s_op = &nfs4_sops;
err = nfs_sb_init(sb, authflavour);
if (err == 0)
return 0;
diff -puN fs/nfs/nfs3proc.c~nfs-27-atomic_open fs/nfs/nfs3proc.c
--- 25/fs/nfs/nfs3proc.c~nfs-27-atomic_open 2004-01-14 02:10:00.000000000 -0800
+++ 25-akpm/fs/nfs/nfs3proc.c 2004-01-14 02:10:00.000000000 -0800
@@ -898,6 +898,8 @@ nfs3_request_compatible(struct nfs_page
struct nfs_rpc_ops nfs_v3_clientops = {
.version = 3, /* protocol version */
+ .dentry_ops = &nfs_dentry_operations,
+ .dir_inode_ops = &nfs_dir_inode_operations,
.getroot = nfs3_proc_get_root,
.getattr = nfs3_proc_getattr,
.setattr = nfs3_proc_setattr,
diff -puN fs/nfs/nfs4proc.c~nfs-27-atomic_open fs/nfs/nfs4proc.c
--- 25/fs/nfs/nfs4proc.c~nfs-27-atomic_open 2004-01-14 02:10:00.000000000 -0800
+++ 25-akpm/fs/nfs/nfs4proc.c 2004-01-14 02:10:00.000000000 -0800
@@ -45,6 +45,7 @@
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <linux/smp_lock.h>
+#include <linux/namei.h>
#define NFSDBG_FACILITY NFSDBG_PROC
@@ -509,6 +510,9 @@ nfs4_open_reclaim(struct nfs4_state_owne
return status;
}
+/*
+ * Returns an nfs4_state + an referenced inode
+ */
struct nfs4_state *
nfs4_do_open(struct inode *dir, struct qstr *name, int flags, struct iattr *sattr, struct rpc_cred *cred)
{
@@ -617,19 +621,23 @@ retry:
up(&sp->so_sema);
nfs4_put_state_owner(sp);
- iput(inode);
return state;
out_up:
up(&sp->so_sema);
nfs4_put_state_owner(sp);
- if (state)
+ if (state) {
nfs4_put_open_state(state);
- if (inode)
+ state = NULL;
+ }
+ if (inode) {
iput(inode);
+ inode = NULL;
+ }
status = nfs4_handle_error(server, status);
if (!status)
goto retry;
+ BUG_ON(status < -1000 || status > 0);
out:
return ERR_PTR(status);
}
@@ -718,6 +726,56 @@ nfs4_do_close(struct inode *inode, struc
return status;
}
+struct inode *
+nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
+{
+ struct iattr attr;
+ struct rpc_cred *cred;
+ struct nfs4_state *state;
+
+ if (nd->flags & LOOKUP_CREATE) {
+ attr.ia_mode = nd->intent.open.create_mode;
+ attr.ia_valid = ATTR_MODE;
+ if (!IS_POSIXACL(dir))
+ attr.ia_mode &= ~current->fs->umask;
+ } else {
+ attr.ia_valid = 0;
+ BUG_ON(nd->intent.open.flags & O_CREAT);
+ }
+
+ cred = rpcauth_lookupcred(NFS_SERVER(dir)->client->cl_auth, 0);
+ state = nfs4_do_open(dir, &dentry->d_name, nd->intent.open.flags, &attr, cred);
+ put_rpccred(cred);
+ if (IS_ERR(state))
+ return (struct inode *)state;
+ return state->inode;
+}
+
+int
+nfs4_open_revalidate(struct inode *dir, struct dentry *dentry, int openflags)
+{
+ struct rpc_cred *cred;
+ struct nfs4_state *state;
+ struct inode *inode;
+
+ cred = rpcauth_lookupcred(NFS_SERVER(dir)->client->cl_auth, 0);
+ state = nfs4_do_open(dir, &dentry->d_name, openflags, NULL, cred);
+ put_rpccred(cred);
+ if (state == ERR_PTR(-ENOENT) && dentry->d_inode == 0)
+ return 1;
+ if (IS_ERR(state))
+ return 0;
+ inode = state->inode;
+ if (inode == dentry->d_inode) {
+ iput(inode);
+ return 1;
+ }
+ d_drop(dentry);
+ nfs4_put_open_state(state);
+ iput(inode);
+ return 0;
+}
+
static int
nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
struct nfs_fattr *fattr)
@@ -808,28 +866,39 @@ nfs4_proc_setattr(struct dentry *dentry,
struct inode * inode = dentry->d_inode;
int size_change = sattr->ia_valid & ATTR_SIZE;
struct nfs4_state *state = NULL;
- int status;
+ int need_iput = 0;
+ int status;
fattr->valid = 0;
if (size_change) {
- struct rpc_cred *cred = rpcauth_lookupcred(NFS_SERVER(inode)->client->cl_auth, 0);
- state = nfs4_do_open(dentry->d_parent->d_inode,
+ state = nfs4_find_state_bypid(inode, current->pid);
+
+ if (!state) {
+ struct rpc_cred *cred = rpcauth_lookupcred(NFS_SERVER(inode)->client->cl_auth, 0);
+ state = nfs4_do_open(dentry->d_parent->d_inode,
&dentry->d_name, FMODE_WRITE, NULL, cred);
- put_rpccred(cred);
+ put_rpccred(cred);
+ need_iput = 1;
+ }
if (IS_ERR(state))
return PTR_ERR(state);
if (state->inode != inode) {
- printk(KERN_WARNING "nfs: raced in setattr, returning -EIO\n");
- nfs4_put_open_state(state);
- return -EIO;
+ printk(KERN_WARNING "nfs: raced in setattr (%p != %p), returning -EIO\n", inode, state->inode);
+ status = -EIO;
+ goto out;
}
}
status = nfs4_do_setattr(NFS_SERVER(inode), fattr,
NFS_FH(inode), sattr, state);
- if (state)
+out:
+ if (state) {
+ inode = state->inode;
nfs4_put_open_state(state);
+ if (need_iput)
+ iput(inode);
+ }
return status;
}
@@ -1085,18 +1154,18 @@ nfs4_proc_create(struct inode *dir, stru
state = nfs4_do_open(dir, name, flags, sattr, cred);
put_rpccred(cred);
if (!IS_ERR(state)) {
- inode = igrab(state->inode);
+ inode = state->inode;
if (flags & O_EXCL) {
struct nfs_fattr fattr;
int status;
status = nfs4_do_setattr(NFS_SERVER(dir), &fattr,
NFS_FH(inode), sattr, state);
if (status != 0) {
+ nfs4_put_open_state(state);
iput(inode);
inode = ERR_PTR(status);
}
}
- nfs4_put_open_state(state);
} else
inode = (struct inode *)state;
return inode;
@@ -1672,43 +1741,28 @@ static int
nfs4_proc_file_open(struct inode *inode, struct file *filp)
{
struct dentry *dentry = filp->f_dentry;
- struct inode *dir = dentry->d_parent->d_inode;
- struct rpc_cred *cred;
struct nfs4_state *state;
- int flags = filp->f_flags;
- int status = 0;
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);
- if ((flags + 1) & O_ACCMODE)
- flags++;
-
- lock_kernel();
-/*
-* We have already opened the file "O_EXCL" in nfs4_proc_create!!
-* This ugliness will go away with lookup-intent...
-*/
- cred = rpcauth_lookupcred(NFS_SERVER(inode)->client->cl_auth, 0);
- state = nfs4_do_open(dir, &dentry->d_name, flags, NULL, cred);
- if (IS_ERR(state)) {
- status = PTR_ERR(state);
- state = NULL;
- } else if (filp->f_mode & FMODE_WRITE)
- nfs_set_mmcred(inode, cred);
- if (inode != filp->f_dentry->d_inode) {
+ /* Find our open stateid */
+ state = nfs4_find_state_bypid(inode, current->pid);
+ if (state == NULL) {
printk(KERN_WARNING "NFS: v4 raced in function %s\n", __FUNCTION__);
- status = -EIO; /* ERACE actually */
- nfs4_put_open_state(state);
- state = NULL;
+ return -EIO; /* ERACE actually */
+ }
+ nfs4_put_open_state(state);
+ if (filp->f_mode & FMODE_WRITE) {
+ lock_kernel();
+ nfs_set_mmcred(inode, state->owner->so_cred);
+ unlock_kernel();
}
filp->private_data = state;
- put_rpccred(cred);
- unlock_kernel();
- return status;
+ return 0;
}
/*
@@ -1922,6 +1976,8 @@ nfs4_proc_setclientid_confirm(struct nfs
struct nfs_rpc_ops nfs_v4_clientops = {
.version = 4, /* protocol version */
+ .dentry_ops = &nfs4_dentry_operations,
+ .dir_inode_ops = &nfs4_dir_inode_operations,
.getroot = nfs4_proc_get_root,
.getattr = nfs4_proc_getattr,
.setattr = nfs4_proc_setattr,
diff -puN fs/nfs/nfs4state.c~nfs-27-atomic_open fs/nfs/nfs4state.c
--- 25/fs/nfs/nfs4state.c~nfs-27-atomic_open 2004-01-14 02:10:00.000000000 -0800
+++ 25-akpm/fs/nfs/nfs4state.c 2004-01-14 02:10:00.000000000 -0800
@@ -349,7 +349,6 @@ nfs4_get_open_state(struct inode *inode,
atomic_inc(&owner->so_count);
list_add(&state->inode_states, &nfsi->open_states);
state->inode = inode;
- atomic_inc(&inode->i_count);
spin_unlock(&inode->i_lock);
} else {
spin_unlock(&inode->i_lock);
@@ -384,7 +383,6 @@ nfs4_put_open_state(struct nfs4_state *s
} while (!status);
}
up(&owner->so_sema);
- iput(inode);
nfs4_free_open_state(state);
nfs4_put_state_owner(owner);
}
diff -puN fs/nfs/proc.c~nfs-27-atomic_open fs/nfs/proc.c
--- 25/fs/nfs/proc.c~nfs-27-atomic_open 2004-01-14 02:10:00.000000000 -0800
+++ 25-akpm/fs/nfs/proc.c 2004-01-14 02:10:00.000000000 -0800
@@ -656,6 +656,8 @@ nfs_request_compatible(struct nfs_page *
struct nfs_rpc_ops nfs_v2_clientops = {
.version = 2, /* protocol version */
+ .dentry_ops = &nfs_dentry_operations,
+ .dir_inode_ops = &nfs_dir_inode_operations,
.getroot = nfs_proc_get_root,
.getattr = nfs_proc_getattr,
.setattr = nfs_proc_setattr,
diff -puN include/linux/nfs_fs.h~nfs-27-atomic_open include/linux/nfs_fs.h
--- 25/include/linux/nfs_fs.h~nfs-27-atomic_open 2004-01-14 02:10:00.000000000 -0800
+++ 25-akpm/include/linux/nfs_fs.h 2004-01-14 02:10:00.000000000 -0800
@@ -558,6 +558,9 @@ struct nfs4_state {
};
+extern struct dentry_operations nfs4_dentry_operations;
+extern struct inode_operations nfs4_dir_inode_operations;
+
/* nfs4proc.c */
extern int nfs4_proc_setclientid(struct nfs4_client *, u32, unsigned short);
extern int nfs4_proc_setclientid_confirm(struct nfs4_client *);
@@ -566,6 +569,8 @@ extern int nfs4_proc_async_renew(struct
extern int nfs4_proc_renew(struct nfs4_client *);
extern int nfs4_do_close(struct inode *, struct nfs4_state *);
extern int nfs4_wait_clnt_recover(struct rpc_clnt *, struct nfs4_client *);
+extern struct inode *nfs4_atomic_open(struct inode *, struct dentry *, struct nameidata *);
+extern int nfs4_open_revalidate(struct inode *, struct dentry *, int);
/* nfs4renewd.c */
extern void nfs4_schedule_state_renewal(struct nfs4_client *);
@@ -581,6 +586,7 @@ extern struct nfs4_state_owner * nfs4_ge
extern void nfs4_put_state_owner(struct nfs4_state_owner *);
extern struct nfs4_state * nfs4_get_open_state(struct inode *, struct nfs4_state_owner *);
extern void nfs4_put_open_state(struct nfs4_state *);
+extern struct nfs4_state *nfs4_find_state_bypid(struct inode *, pid_t);
extern void nfs4_increment_seqid(int status, struct nfs4_state_owner *sp);
extern int nfs4_handle_error(struct nfs_server *, int);
extern void nfs4_schedule_state_recovery(struct nfs4_client *);
diff -puN include/linux/nfs_xdr.h~nfs-27-atomic_open include/linux/nfs_xdr.h
--- 25/include/linux/nfs_xdr.h~nfs-27-atomic_open 2004-01-14 02:10:00.000000000 -0800
+++ 25-akpm/include/linux/nfs_xdr.h 2004-01-14 02:10:00.000000000 -0800
@@ -637,6 +637,8 @@ struct nfs_page;
*/
struct nfs_rpc_ops {
int version; /* Protocol version */
+ struct dentry_operations *dentry_ops;
+ struct inode_operations *dir_inode_ops;
int (*getroot) (struct nfs_server *, struct nfs_fh *,
struct nfs_fattr *);
_