Revision 9e368259ad988356c4c95150fafd1a06af095d98 authored by Andrea Arcangeli on 30 November 2018, 22:09:25 UTC, committed by Linus Torvalds on 30 November 2018, 22:56:14 UTC
Patch series "userfaultfd shmem updates". Jann found two bugs in the userfaultfd shmem MAP_SHARED backend: the lack of the VM_MAYWRITE check and the lack of i_size checks. Then looking into the above we also fixed the MAP_PRIVATE case. Hugh by source review also found a data loss source if UFFDIO_COPY is used on shmem MAP_SHARED PROT_READ mappings (the production usages incidentally run with PROT_READ|PROT_WRITE, so the data loss couldn't happen in those production usages like with QEMU). The whole patchset is marked for stable. We verified QEMU postcopy live migration with guest running on shmem MAP_PRIVATE run as well as before after the fix of shmem MAP_PRIVATE. Regardless if it's shmem or hugetlbfs or MAP_PRIVATE or MAP_SHARED, QEMU unconditionally invokes a punch hole if the guest mapping is filebacked and a MADV_DONTNEED too (needed to get rid of the MAP_PRIVATE COWs and for the anon backend). This patch (of 5): We internally used EFAULT to communicate with the caller, switch to ENOENT, so EFAULT can be used as a non internal retval. Link: http://lkml.kernel.org/r/20181126173452.26955-2-aarcange@redhat.com Fixes: 4c27fe4c4c84 ("userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Hugh Dickins <hughd@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: <stable@vger.kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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nfsfh.h
/* 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 <uapi/linux/nfsd/nfsfh.h>
#include <linux/iversion.h>
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 */
#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 timespec fh_pre_mtime; /* mtime before oper */
struct timespec 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;
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(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_base, &src->fh_base, 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_base.fh_pad, fh2->fh_base.fh_pad, 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(struct knfsd_fh *fh)
{
return ~crc32_le(0xFFFFFFFF, (unsigned char *)&fh->fh_base, fh->fh_size);
}
#else
static inline u32
knfsd_fh_hash(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)
{
u64 chattr;
chattr = stat->ctime.tv_sec;
chattr <<= 30;
chattr += stat->ctime.tv_nsec;
chattr += inode_query_iversion(inode);
return chattr;
}
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 */
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