alistair23-linux/fs/nfsd/vfs.h
Trond Myklebust 83a63072c8 nfsd: fix nfs read eof detection
Currently, the knfsd server assumes that a short read indicates an
end of file. That assumption is incorrect. The short read means that
either we've hit the end of file, or we've hit a read error.

In the case of a read error, the client may want to retry (as per the
implementation recommendations in RFC1813 and RFC7530), but currently it
is being told that it hit an eof.

Move the code to detect eof from version specific code into the generic
nfsd read.

Report eof only in the two following cases:
1) read() returns a zero length short read with no error.
2) the offset+length of the read is >= the file size.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-09-23 16:24:08 -04:00

156 lines
5.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 1995-1997 Olaf Kirch <okir@monad.swb.de>
*/
#ifndef LINUX_NFSD_VFS_H
#define LINUX_NFSD_VFS_H
#include "nfsfh.h"
#include "nfsd.h"
/*
* Flags for nfsd_permission
*/
#define NFSD_MAY_NOP 0
#define NFSD_MAY_EXEC 0x001 /* == MAY_EXEC */
#define NFSD_MAY_WRITE 0x002 /* == MAY_WRITE */
#define NFSD_MAY_READ 0x004 /* == MAY_READ */
#define NFSD_MAY_SATTR 0x008
#define NFSD_MAY_TRUNC 0x010
#define NFSD_MAY_LOCK 0x020
#define NFSD_MAY_MASK 0x03f
/* extra hints to permission and open routines: */
#define NFSD_MAY_OWNER_OVERRIDE 0x040
#define NFSD_MAY_LOCAL_ACCESS 0x080 /* for device special files */
#define NFSD_MAY_BYPASS_GSS_ON_ROOT 0x100
#define NFSD_MAY_NOT_BREAK_LEASE 0x200
#define NFSD_MAY_BYPASS_GSS 0x400
#define NFSD_MAY_READ_IF_EXEC 0x800
#define NFSD_MAY_64BIT_COOKIE 0x1000 /* 64 bit readdir cookies for >= NFSv3 */
#define NFSD_MAY_CREATE (NFSD_MAY_EXEC|NFSD_MAY_WRITE)
#define NFSD_MAY_REMOVE (NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC)
/*
* Callback function for readdir
*/
typedef int (*nfsd_filldir_t)(void *, const char *, int, loff_t, u64, unsigned);
/* nfsd/vfs.c */
int nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
struct svc_export **expp);
__be32 nfsd_lookup(struct svc_rqst *, struct svc_fh *,
const char *, unsigned int, struct svc_fh *);
__be32 nfsd_lookup_dentry(struct svc_rqst *, struct svc_fh *,
const char *, unsigned int,
struct svc_export **, struct dentry **);
__be32 nfsd_setattr(struct svc_rqst *, struct svc_fh *,
struct iattr *, int, time_t);
int nfsd_mountpoint(struct dentry *, struct svc_export *);
#ifdef CONFIG_NFSD_V4
__be32 nfsd4_set_nfs4_label(struct svc_rqst *, struct svc_fh *,
struct xdr_netobj *);
__be32 nfsd4_vfs_fallocate(struct svc_rqst *, struct svc_fh *,
struct file *, loff_t, loff_t, int);
__be32 nfsd4_clone_file_range(struct file *, u64, struct file *,
u64, u64);
#endif /* CONFIG_NFSD_V4 */
__be32 nfsd_create_locked(struct svc_rqst *, struct svc_fh *,
char *name, int len, struct iattr *attrs,
int type, dev_t rdev, struct svc_fh *res);
__be32 nfsd_create(struct svc_rqst *, struct svc_fh *,
char *name, int len, struct iattr *attrs,
int type, dev_t rdev, struct svc_fh *res);
#ifdef CONFIG_NFSD_V3
__be32 nfsd_access(struct svc_rqst *, struct svc_fh *, u32 *, u32 *);
__be32 do_nfsd_create(struct svc_rqst *, struct svc_fh *,
char *name, int len, struct iattr *attrs,
struct svc_fh *res, int createmode,
u32 *verifier, bool *truncp, bool *created);
__be32 nfsd_commit(struct svc_rqst *, struct svc_fh *,
loff_t, unsigned long);
#endif /* CONFIG_NFSD_V3 */
int nfsd_open_break_lease(struct inode *, int);
__be32 nfsd_open(struct svc_rqst *, struct svc_fh *, umode_t,
int, struct file **);
__be32 nfsd_open_verified(struct svc_rqst *, struct svc_fh *, umode_t,
int, struct file **);
__be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct file *file, loff_t offset,
unsigned long *count,
u32 *eof);
__be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct file *file, loff_t offset,
struct kvec *vec, int vlen,
unsigned long *count,
u32 *eof);
__be32 nfsd_read(struct svc_rqst *, struct svc_fh *,
loff_t, struct kvec *, int, unsigned long *,
u32 *eof);
__be32 nfsd_write(struct svc_rqst *, struct svc_fh *, loff_t,
struct kvec *, int, unsigned long *, int);
__be32 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct file *file, loff_t offset,
struct kvec *vec, int vlen, unsigned long *cnt,
int stable);
__be32 nfsd_readlink(struct svc_rqst *, struct svc_fh *,
char *, int *);
__be32 nfsd_symlink(struct svc_rqst *, struct svc_fh *,
char *name, int len, char *path,
struct svc_fh *res);
__be32 nfsd_link(struct svc_rqst *, struct svc_fh *,
char *, int, struct svc_fh *);
ssize_t nfsd_copy_file_range(struct file *, u64,
struct file *, u64, u64);
__be32 nfsd_rename(struct svc_rqst *,
struct svc_fh *, char *, int,
struct svc_fh *, char *, int);
__be32 nfsd_unlink(struct svc_rqst *, struct svc_fh *, int type,
char *name, int len);
__be32 nfsd_readdir(struct svc_rqst *, struct svc_fh *,
loff_t *, struct readdir_cd *, nfsd_filldir_t);
__be32 nfsd_statfs(struct svc_rqst *, struct svc_fh *,
struct kstatfs *, int access);
__be32 nfsd_permission(struct svc_rqst *, struct svc_export *,
struct dentry *, int);
static inline int fh_want_write(struct svc_fh *fh)
{
int ret;
if (fh->fh_want_write)
return 0;
ret = mnt_want_write(fh->fh_export->ex_path.mnt);
if (!ret)
fh->fh_want_write = true;
return ret;
}
static inline void fh_drop_write(struct svc_fh *fh)
{
if (fh->fh_want_write) {
fh->fh_want_write = false;
mnt_drop_write(fh->fh_export->ex_path.mnt);
}
}
static inline __be32 fh_getattr(struct svc_fh *fh, struct kstat *stat)
{
struct path p = {.mnt = fh->fh_export->ex_path.mnt,
.dentry = fh->fh_dentry};
return nfserrno(vfs_getattr(&p, stat, STATX_BASIC_STATS,
AT_STATX_SYNC_AS_STAT));
}
static inline int nfsd_create_is_exclusive(int createmode)
{
return createmode == NFS3_CREATE_EXCLUSIVE
|| createmode == NFS4_CREATE_EXCLUSIVE4_1;
}
#endif /* LINUX_NFSD_VFS_H */