linux-stable/fs/nfsd/nfsfh.h
NeilBrown d8b26071e6 NFSD: simplify struct nfsfh
Most of the fields in 'struct knfsd_fh' are 2 levels deep (a union and a
struct) and are accessed using macros like:

 #define fh_FOO fh_base.fh_new.fb_FOO

This patch makes the union and struct anonymous, so that "fh_FOO" can be
a name directly within 'struct knfsd_fh' and the #defines aren't needed.

The file handle as a whole is sometimes accessed as "fh_base" or
"fh_base.fh_pad", neither of which are particularly helpful names.
As the struct holding the filehandle is now anonymous, we
cannot use the name of that, so we union it with 'fh_raw' and use that
where the raw filehandle is needed.  fh_raw also ensure the structure is
large enough for the largest possible filehandle.

fh_raw is a 'char' array, removing any need to cast it for memcpy etc.

SVCFH_fmt() is simplified using the "%ph" printk format.  This
changes the appearance of filehandles in dprintk() debugging, making
them a little more precise.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2021-10-02 15:51:10 -04:00

381 lines
9.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
*
* This file describes the layout of the file handles as passed
* over the wire.
*/
#ifndef _LINUX_NFSD_NFSFH_H
#define _LINUX_NFSD_NFSFH_H
#include <linux/crc32.h>
#include <linux/sunrpc/svc.h>
#include <linux/iversion.h>
#include <linux/exportfs.h>
#include <linux/nfs4.h>
/*
* The file handle starts with a sequence of four-byte words.
* The first word contains a version number (1) and three descriptor bytes
* that tell how the remaining 3 variable length fields should be handled.
* These three bytes are auth_type, fsid_type and fileid_type.
*
* All four-byte values are in host-byte-order.
*
* The auth_type field is deprecated and must be set to 0.
*
* The fsid_type identifies how the filesystem (or export point) is
* encoded.
* Current values:
* 0 - 4 byte device id (ms-2-bytes major, ls-2-bytes minor), 4byte inode number
* NOTE: we cannot use the kdev_t device id value, because kdev_t.h
* says we mustn't. We must break it up and reassemble.
* 1 - 4 byte user specified identifier
* 2 - 4 byte major, 4 byte minor, 4 byte inode number - DEPRECATED
* 3 - 4 byte device id, encoded for user-space, 4 byte inode number
* 4 - 4 byte inode number and 4 byte uuid
* 5 - 8 byte uuid
* 6 - 16 byte uuid
* 7 - 8 byte inode number and 16 byte uuid
*
* The fileid_type identifies how the file within the filesystem is encoded.
* The values for this field are filesystem specific, exccept that
* filesystems must not use the values '0' or '0xff'. 'See enum fid_type'
* in include/linux/exportfs.h for currently registered values.
*/
struct knfsd_fh {
unsigned int fh_size; /*
* Points to the current size while
* building a new file handle.
*/
union {
char fh_raw[NFS4_FHSIZE];
struct {
u8 fh_version; /* == 1 */
u8 fh_auth_type; /* deprecated */
u8 fh_fsid_type;
u8 fh_fileid_type;
u32 fh_fsid[]; /* flexible-array member */
};
};
};
static inline __u32 ino_t_to_u32(ino_t ino)
{
return (__u32) ino;
}
static inline ino_t u32_to_ino_t(__u32 uino)
{
return (ino_t) uino;
}
/*
* This is the internal representation of an NFS handle used in knfsd.
* pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
*/
typedef struct svc_fh {
struct knfsd_fh fh_handle; /* FH data */
int fh_maxsize; /* max size for fh_handle */
struct dentry * fh_dentry; /* validated dentry */
struct svc_export * fh_export; /* export pointer */
bool fh_locked; /* inode locked by us */
bool fh_want_write; /* remount protection taken */
bool fh_no_wcc; /* no wcc data needed */
bool fh_no_atomic_attr;
/*
* wcc data is not atomic with
* operation
*/
int fh_flags; /* FH flags */
#ifdef CONFIG_NFSD_V3
bool fh_post_saved; /* post-op attrs saved */
bool fh_pre_saved; /* pre-op attrs saved */
/* Pre-op attributes saved during fh_lock */
__u64 fh_pre_size; /* size before operation */
struct timespec64 fh_pre_mtime; /* mtime before oper */
struct timespec64 fh_pre_ctime; /* ctime before oper */
/*
* pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
* to find out if it is valid.
*/
u64 fh_pre_change;
/* Post-op attributes saved in fh_unlock */
struct kstat fh_post_attr; /* full attrs after operation */
u64 fh_post_change; /* nfsv4 change; see above */
#endif /* CONFIG_NFSD_V3 */
} svc_fh;
#define NFSD4_FH_FOREIGN (1<<0)
#define SET_FH_FLAG(c, f) ((c)->fh_flags |= (f))
#define HAS_FH_FLAG(c, f) ((c)->fh_flags & (f))
enum nfsd_fsid {
FSID_DEV = 0,
FSID_NUM,
FSID_MAJOR_MINOR,
FSID_ENCODE_DEV,
FSID_UUID4_INUM,
FSID_UUID8,
FSID_UUID16,
FSID_UUID16_INUM,
};
enum fsid_source {
FSIDSOURCE_DEV,
FSIDSOURCE_FSID,
FSIDSOURCE_UUID,
};
extern enum fsid_source fsid_source(const struct svc_fh *fhp);
/*
* This might look a little large to "inline" but in all calls except
* one, 'vers' is constant so moste of the function disappears.
*
* In some cases the values are considered to be host endian and in
* others, net endian. fsidv is always considered to be u32 as the
* callers don't know which it will be. So we must use __force to keep
* sparse from complaining. Since these values are opaque to the
* client, that shouldn't be a problem.
*/
static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
u32 fsid, unsigned char *uuid)
{
u32 *up;
switch(vers) {
case FSID_DEV:
fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
MINOR(dev));
fsidv[1] = ino_t_to_u32(ino);
break;
case FSID_NUM:
fsidv[0] = fsid;
break;
case FSID_MAJOR_MINOR:
fsidv[0] = (__force __u32)htonl(MAJOR(dev));
fsidv[1] = (__force __u32)htonl(MINOR(dev));
fsidv[2] = ino_t_to_u32(ino);
break;
case FSID_ENCODE_DEV:
fsidv[0] = new_encode_dev(dev);
fsidv[1] = ino_t_to_u32(ino);
break;
case FSID_UUID4_INUM:
/* 4 byte fsid and inode number */
up = (u32*)uuid;
fsidv[0] = ino_t_to_u32(ino);
fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
break;
case FSID_UUID8:
/* 8 byte fsid */
up = (u32*)uuid;
fsidv[0] = up[0] ^ up[2];
fsidv[1] = up[1] ^ up[3];
break;
case FSID_UUID16:
/* 16 byte fsid - NFSv3+ only */
memcpy(fsidv, uuid, 16);
break;
case FSID_UUID16_INUM:
/* 8 byte inode and 16 byte fsid */
*(u64*)fsidv = (u64)ino;
memcpy(fsidv+2, uuid, 16);
break;
default: BUG();
}
}
static inline int key_len(int type)
{
switch(type) {
case FSID_DEV: return 8;
case FSID_NUM: return 4;
case FSID_MAJOR_MINOR: return 12;
case FSID_ENCODE_DEV: return 8;
case FSID_UUID4_INUM: return 8;
case FSID_UUID8: return 8;
case FSID_UUID16: return 16;
case FSID_UUID16_INUM: return 24;
default: return 0;
}
}
/*
* Shorthand for dprintk()'s
*/
extern char * SVCFH_fmt(struct svc_fh *fhp);
/*
* Function prototypes
*/
__be32 fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
__be32 fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
__be32 fh_update(struct svc_fh *);
void fh_put(struct svc_fh *);
static __inline__ struct svc_fh *
fh_copy(struct svc_fh *dst, struct svc_fh *src)
{
WARN_ON(src->fh_dentry || src->fh_locked);
*dst = *src;
return dst;
}
static inline void
fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
{
dst->fh_size = src->fh_size;
memcpy(&dst->fh_raw, &src->fh_raw, src->fh_size);
}
static __inline__ struct svc_fh *
fh_init(struct svc_fh *fhp, int maxsize)
{
memset(fhp, 0, sizeof(*fhp));
fhp->fh_maxsize = maxsize;
return fhp;
}
static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
{
if (fh1->fh_size != fh2->fh_size)
return false;
if (memcmp(fh1->fh_raw, fh2->fh_raw, fh1->fh_size) != 0)
return false;
return true;
}
static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
{
if (fh1->fh_fsid_type != fh2->fh_fsid_type)
return false;
if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)
return false;
return true;
}
#ifdef CONFIG_CRC32
/**
* knfsd_fh_hash - calculate the crc32 hash for the filehandle
* @fh - pointer to filehandle
*
* returns a crc32 hash for the filehandle that is compatible with
* the one displayed by "wireshark".
*/
static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
{
return ~crc32_le(0xFFFFFFFF, fh->fh_raw, fh->fh_size);
}
#else
static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
{
return 0;
}
#endif
#ifdef CONFIG_NFSD_V3
/*
* The wcc data stored in current_fh should be cleared
* between compound ops.
*/
static inline void
fh_clear_wcc(struct svc_fh *fhp)
{
fhp->fh_post_saved = false;
fhp->fh_pre_saved = false;
}
/*
* We could use i_version alone as the change attribute. However,
* i_version can go backwards after a reboot. On its own that doesn't
* necessarily cause a problem, but if i_version goes backwards and then
* is incremented again it could reuse a value that was previously used
* before boot, and a client who queried the two values might
* incorrectly assume nothing changed.
*
* By using both ctime and the i_version counter we guarantee that as
* long as time doesn't go backwards we never reuse an old value.
*/
static inline u64 nfsd4_change_attribute(struct kstat *stat,
struct inode *inode)
{
if (inode->i_sb->s_export_op->fetch_iversion)
return inode->i_sb->s_export_op->fetch_iversion(inode);
else if (IS_I_VERSION(inode)) {
u64 chattr;
chattr = stat->ctime.tv_sec;
chattr <<= 30;
chattr += stat->ctime.tv_nsec;
chattr += inode_query_iversion(inode);
return chattr;
} else
return time_to_chattr(&stat->ctime);
}
extern void fill_pre_wcc(struct svc_fh *fhp);
extern void fill_post_wcc(struct svc_fh *fhp);
#else
#define fh_clear_wcc(ignored)
#define fill_pre_wcc(ignored)
#define fill_post_wcc(notused)
#endif /* CONFIG_NFSD_V3 */
/*
* Lock a file handle/inode
* NOTE: both fh_lock and fh_unlock are done "by hand" in
* vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
* so, any changes here should be reflected there.
*/
static inline void
fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
{
struct dentry *dentry = fhp->fh_dentry;
struct inode *inode;
BUG_ON(!dentry);
if (fhp->fh_locked) {
printk(KERN_WARNING "fh_lock: %pd2 already locked!\n",
dentry);
return;
}
inode = d_inode(dentry);
inode_lock_nested(inode, subclass);
fill_pre_wcc(fhp);
fhp->fh_locked = true;
}
static inline void
fh_lock(struct svc_fh *fhp)
{
fh_lock_nested(fhp, I_MUTEX_NORMAL);
}
/*
* Unlock a file handle/inode
*/
static inline void
fh_unlock(struct svc_fh *fhp)
{
if (fhp->fh_locked) {
fill_post_wcc(fhp);
inode_unlock(d_inode(fhp->fh_dentry));
fhp->fh_locked = false;
}
}
#endif /* _LINUX_NFSD_NFSFH_H */