linux/fs/nfsd/nfsfh.c
Linus Torvalds 05e6295f7b fs.idmapped.v6.3
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCY+5NlQAKCRCRxhvAZXjc
 orOaAP9i2h3OJy95nO2Fpde0Bt2UT+oulKCCcGlvXJ8/+TQpyQD/ZQq47gFQ0EAz
 Br5NxeyGeecAb0lHpFz+CpLGsxMrMwQ=
 =+BG5
 -----END PGP SIGNATURE-----

Merge tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull vfs idmapping updates from Christian Brauner:

 - Last cycle we introduced the dedicated struct mnt_idmap type for
   mount idmapping and the required infrastucture in 256c8aed2b ("fs:
   introduce dedicated idmap type for mounts"). As promised in last
   cycle's pull request message this converts everything to rely on
   struct mnt_idmap.

   Currently we still pass around the plain namespace that was attached
   to a mount. This is in general pretty convenient but it makes it easy
   to conflate namespaces that are relevant on the filesystem with
   namespaces that are relevant on the mount level. Especially for
   non-vfs developers without detailed knowledge in this area this was a
   potential source for bugs.

   This finishes the conversion. Instead of passing the plain namespace
   around this updates all places that currently take a pointer to a
   mnt_userns with a pointer to struct mnt_idmap.

   Now that the conversion is done all helpers down to the really
   low-level helpers only accept a struct mnt_idmap argument instead of
   two namespace arguments.

   Conflating mount and other idmappings will now cause the compiler to
   complain loudly thus eliminating the possibility of any bugs. This
   makes it impossible for filesystem developers to mix up mount and
   filesystem idmappings as they are two distinct types and require
   distinct helpers that cannot be used interchangeably.

   Everything associated with struct mnt_idmap is moved into a single
   separate file. With that change no code can poke around in struct
   mnt_idmap. It can only be interacted with through dedicated helpers.
   That means all filesystems are and all of the vfs is completely
   oblivious to the actual implementation of idmappings.

   We are now also able to extend struct mnt_idmap as we see fit. For
   example, we can decouple it completely from namespaces for users that
   don't require or don't want to use them at all. We can also extend
   the concept of idmappings so we can cover filesystem specific
   requirements.

   In combination with the vfs{g,u}id_t work we finished in v6.2 this
   makes this feature substantially more robust and thus difficult to
   implement wrong by a given filesystem and also protects the vfs.

 - Enable idmapped mounts for tmpfs and fulfill a longstanding request.

   A long-standing request from users had been to make it possible to
   create idmapped mounts for tmpfs. For example, to share the host's
   tmpfs mount between multiple sandboxes. This is a prerequisite for
   some advanced Kubernetes cases. Systemd also has a range of use-cases
   to increase service isolation. And there are more users of this.

   However, with all of the other work going on this was way down on the
   priority list but luckily someone other than ourselves picked this
   up.

   As usual the patch is tiny as all the infrastructure work had been
   done multiple kernel releases ago. In addition to all the tests that
   we already have I requested that Rodrigo add a dedicated tmpfs
   testsuite for idmapped mounts to xfstests. It is to be included into
   xfstests during the v6.3 development cycle. This should add a slew of
   additional tests.

* tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits)
  shmem: support idmapped mounts for tmpfs
  fs: move mnt_idmap
  fs: port vfs{g,u}id helpers to mnt_idmap
  fs: port fs{g,u}id helpers to mnt_idmap
  fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
  fs: port i_{g,u}id_{needs_}update() to mnt_idmap
  quota: port to mnt_idmap
  fs: port privilege checking helpers to mnt_idmap
  fs: port inode_owner_or_capable() to mnt_idmap
  fs: port inode_init_owner() to mnt_idmap
  fs: port acl to mnt_idmap
  fs: port xattr to mnt_idmap
  fs: port ->permission() to pass mnt_idmap
  fs: port ->fileattr_set() to pass mnt_idmap
  fs: port ->set_acl() to pass mnt_idmap
  fs: port ->get_acl() to pass mnt_idmap
  fs: port ->tmpfile() to pass mnt_idmap
  fs: port ->rename() to pass mnt_idmap
  fs: port ->mknod() to pass mnt_idmap
  fs: port ->mkdir() to pass mnt_idmap
  ...
2023-02-20 11:53:11 -08:00

793 lines
21 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* NFS server file handle treatment.
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
* Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
* Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
* ... and again Southern-Winter 2001 to support export_operations
*/
#include <linux/exportfs.h>
#include <linux/sunrpc/svcauth_gss.h>
#include "nfsd.h"
#include "vfs.h"
#include "auth.h"
#include "trace.h"
#define NFSDDBG_FACILITY NFSDDBG_FH
/*
* our acceptability function.
* if NOSUBTREECHECK, accept anything
* if not, require that we can walk up to exp->ex_dentry
* doing some checks on the 'x' bits
*/
static int nfsd_acceptable(void *expv, struct dentry *dentry)
{
struct svc_export *exp = expv;
int rv;
struct dentry *tdentry;
struct dentry *parent;
if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
return 1;
tdentry = dget(dentry);
while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
/* make sure parents give x permission to user */
int err;
parent = dget_parent(tdentry);
err = inode_permission(&nop_mnt_idmap,
d_inode(parent), MAY_EXEC);
if (err < 0) {
dput(parent);
break;
}
dput(tdentry);
tdentry = parent;
}
if (tdentry != exp->ex_path.dentry)
dprintk("nfsd_acceptable failed at %p %pd\n", tdentry, tdentry);
rv = (tdentry == exp->ex_path.dentry);
dput(tdentry);
return rv;
}
/* Type check. The correct error return for type mismatches does not seem to be
* generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
* comment in the NFSv3 spec says this is incorrect (implementation notes for
* the write call).
*/
static inline __be32
nfsd_mode_check(struct svc_rqst *rqstp, struct dentry *dentry,
umode_t requested)
{
umode_t mode = d_inode(dentry)->i_mode & S_IFMT;
if (requested == 0) /* the caller doesn't care */
return nfs_ok;
if (mode == requested) {
if (mode == S_IFDIR && !d_can_lookup(dentry)) {
WARN_ON_ONCE(1);
return nfserr_notdir;
}
return nfs_ok;
}
/*
* v4 has an error more specific than err_notdir which we should
* return in preference to err_notdir:
*/
if (rqstp->rq_vers == 4 && mode == S_IFLNK)
return nfserr_symlink;
if (requested == S_IFDIR)
return nfserr_notdir;
if (mode == S_IFDIR)
return nfserr_isdir;
return nfserr_inval;
}
static bool nfsd_originating_port_ok(struct svc_rqst *rqstp, int flags)
{
if (flags & NFSEXP_INSECURE_PORT)
return true;
/* We don't require gss requests to use low ports: */
if (rqstp->rq_cred.cr_flavor >= RPC_AUTH_GSS)
return true;
return test_bit(RQ_SECURE, &rqstp->rq_flags);
}
static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
struct svc_export *exp)
{
int flags = nfsexp_flags(rqstp, exp);
/* Check if the request originated from a secure port. */
if (!nfsd_originating_port_ok(rqstp, flags)) {
RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
dprintk("nfsd: request from insecure port %s!\n",
svc_print_addr(rqstp, buf, sizeof(buf)));
return nfserr_perm;
}
/* Set user creds for this exportpoint */
return nfserrno(nfsd_setuser(rqstp, exp));
}
static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
struct dentry *dentry, struct svc_export *exp)
{
if (!(exp->ex_flags & NFSEXP_V4ROOT))
return nfs_ok;
/*
* v2/v3 clients have no need for the V4ROOT export--they use
* the mount protocl instead; also, further V4ROOT checks may be
* in v4-specific code, in which case v2/v3 clients could bypass
* them.
*/
if (!nfsd_v4client(rqstp))
return nfserr_stale;
/*
* We're exposing only the directories and symlinks that have to be
* traversed on the way to real exports:
*/
if (unlikely(!d_is_dir(dentry) &&
!d_is_symlink(dentry)))
return nfserr_stale;
/*
* A pseudoroot export gives permission to access only one
* single directory; the kernel has to make another upcall
* before granting access to anything else under it:
*/
if (unlikely(dentry != exp->ex_path.dentry))
return nfserr_stale;
return nfs_ok;
}
/*
* Use the given filehandle to look up the corresponding export and
* dentry. On success, the results are used to set fh_export and
* fh_dentry.
*/
static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
{
struct knfsd_fh *fh = &fhp->fh_handle;
struct fid *fid = NULL;
struct svc_export *exp;
struct dentry *dentry;
int fileid_type;
int data_left = fh->fh_size/4;
int len;
__be32 error;
error = nfserr_stale;
if (rqstp->rq_vers > 2)
error = nfserr_badhandle;
if (rqstp->rq_vers == 4 && fh->fh_size == 0)
return nfserr_nofilehandle;
if (fh->fh_version != 1)
return error;
if (--data_left < 0)
return error;
if (fh->fh_auth_type != 0)
return error;
len = key_len(fh->fh_fsid_type) / 4;
if (len == 0)
return error;
if (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
/* deprecated, convert to type 3 */
len = key_len(FSID_ENCODE_DEV)/4;
fh->fh_fsid_type = FSID_ENCODE_DEV;
/*
* struct knfsd_fh uses host-endian fields, which are
* sometimes used to hold net-endian values. This
* confuses sparse, so we must use __force here to
* keep it from complaining.
*/
fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl((__force __be32)fh->fh_fsid[0]),
ntohl((__force __be32)fh->fh_fsid[1])));
fh->fh_fsid[1] = fh->fh_fsid[2];
}
data_left -= len;
if (data_left < 0)
return error;
exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_fsid);
fid = (struct fid *)(fh->fh_fsid + len);
error = nfserr_stale;
if (IS_ERR(exp)) {
trace_nfsd_set_fh_dentry_badexport(rqstp, fhp, PTR_ERR(exp));
if (PTR_ERR(exp) == -ENOENT)
return error;
return nfserrno(PTR_ERR(exp));
}
if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
/* Elevate privileges so that the lack of 'r' or 'x'
* permission on some parent directory will
* not stop exportfs_decode_fh from being able
* to reconnect a directory into the dentry cache.
* The same problem can affect "SUBTREECHECK" exports,
* but as nfsd_acceptable depends on correct
* access control settings being in effect, we cannot
* fix that case easily.
*/
struct cred *new = prepare_creds();
if (!new) {
error = nfserrno(-ENOMEM);
goto out;
}
new->cap_effective =
cap_raise_nfsd_set(new->cap_effective,
new->cap_permitted);
put_cred(override_creds(new));
put_cred(new);
} else {
error = nfsd_setuser_and_check_port(rqstp, exp);
if (error)
goto out;
}
/*
* Look up the dentry using the NFS file handle.
*/
error = nfserr_stale;
if (rqstp->rq_vers > 2)
error = nfserr_badhandle;
fileid_type = fh->fh_fileid_type;
if (fileid_type == FILEID_ROOT)
dentry = dget(exp->ex_path.dentry);
else {
dentry = exportfs_decode_fh_raw(exp->ex_path.mnt, fid,
data_left, fileid_type,
nfsd_acceptable, exp);
if (IS_ERR_OR_NULL(dentry)) {
trace_nfsd_set_fh_dentry_badhandle(rqstp, fhp,
dentry ? PTR_ERR(dentry) : -ESTALE);
switch (PTR_ERR(dentry)) {
case -ENOMEM:
case -ETIMEDOUT:
break;
default:
dentry = ERR_PTR(-ESTALE);
}
}
}
if (dentry == NULL)
goto out;
if (IS_ERR(dentry)) {
if (PTR_ERR(dentry) != -EINVAL)
error = nfserrno(PTR_ERR(dentry));
goto out;
}
if (d_is_dir(dentry) &&
(dentry->d_flags & DCACHE_DISCONNECTED)) {
printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n",
dentry);
}
fhp->fh_dentry = dentry;
fhp->fh_export = exp;
switch (rqstp->rq_vers) {
case 4:
if (dentry->d_sb->s_export_op->flags & EXPORT_OP_NOATOMIC_ATTR)
fhp->fh_no_atomic_attr = true;
break;
case 3:
if (dentry->d_sb->s_export_op->flags & EXPORT_OP_NOWCC)
fhp->fh_no_wcc = true;
break;
case 2:
fhp->fh_no_wcc = true;
}
return 0;
out:
exp_put(exp);
return error;
}
/**
* fh_verify - filehandle lookup and access checking
* @rqstp: pointer to current rpc request
* @fhp: filehandle to be verified
* @type: expected type of object pointed to by filehandle
* @access: type of access needed to object
*
* Look up a dentry from the on-the-wire filehandle, check the client's
* access to the export, and set the current task's credentials.
*
* Regardless of success or failure of fh_verify(), fh_put() should be
* called on @fhp when the caller is finished with the filehandle.
*
* fh_verify() may be called multiple times on a given filehandle, for
* example, when processing an NFSv4 compound. The first call will look
* up a dentry using the on-the-wire filehandle. Subsequent calls will
* skip the lookup and just perform the other checks and possibly change
* the current task's credentials.
*
* @type specifies the type of object expected using one of the S_IF*
* constants defined in include/linux/stat.h. The caller may use zero
* to indicate that it doesn't care, or a negative integer to indicate
* that it expects something not of the given type.
*
* @access is formed from the NFSD_MAY_* constants defined in
* fs/nfsd/vfs.h.
*/
__be32
fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int access)
{
struct svc_export *exp = NULL;
struct dentry *dentry;
__be32 error;
if (!fhp->fh_dentry) {
error = nfsd_set_fh_dentry(rqstp, fhp);
if (error)
goto out;
}
dentry = fhp->fh_dentry;
exp = fhp->fh_export;
trace_nfsd_fh_verify(rqstp, fhp, type, access);
/*
* We still have to do all these permission checks, even when
* fh_dentry is already set:
* - fh_verify may be called multiple times with different
* "access" arguments (e.g. nfsd_proc_create calls
* fh_verify(...,NFSD_MAY_EXEC) first, then later (in
* nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
* - in the NFSv4 case, the filehandle may have been filled
* in by fh_compose, and given a dentry, but further
* compound operations performed with that filehandle
* still need permissions checks. In the worst case, a
* mountpoint crossing may have changed the export
* options, and we may now need to use a different uid
* (for example, if different id-squashing options are in
* effect on the new filesystem).
*/
error = check_pseudo_root(rqstp, dentry, exp);
if (error)
goto out;
error = nfsd_setuser_and_check_port(rqstp, exp);
if (error)
goto out;
error = nfsd_mode_check(rqstp, dentry, type);
if (error)
goto out;
/*
* pseudoflavor restrictions are not enforced on NLM,
* which clients virtually always use auth_sys for,
* even while using RPCSEC_GSS for NFS.
*/
if (access & NFSD_MAY_LOCK || access & NFSD_MAY_BYPASS_GSS)
goto skip_pseudoflavor_check;
/*
* Clients may expect to be able to use auth_sys during mount,
* even if they use gss for everything else; see section 2.3.2
* of rfc 2623.
*/
if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
&& exp->ex_path.dentry == dentry)
goto skip_pseudoflavor_check;
error = check_nfsd_access(exp, rqstp);
if (error)
goto out;
skip_pseudoflavor_check:
/* Finally, check access permissions. */
error = nfsd_permission(rqstp, exp, dentry, access);
out:
trace_nfsd_fh_verify_err(rqstp, fhp, type, access, error);
if (error == nfserr_stale)
nfsd_stats_fh_stale_inc(exp);
return error;
}
/*
* Compose a file handle for an NFS reply.
*
* Note that when first composed, the dentry may not yet have
* an inode. In this case a call to fh_update should be made
* before the fh goes out on the wire ...
*/
static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
struct dentry *dentry)
{
if (dentry != exp->ex_path.dentry) {
struct fid *fid = (struct fid *)
(fhp->fh_handle.fh_fsid + fhp->fh_handle.fh_size/4 - 1);
int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
fhp->fh_handle.fh_fileid_type =
exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
fhp->fh_handle.fh_size += maxsize * 4;
} else {
fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
}
}
static bool is_root_export(struct svc_export *exp)
{
return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
}
static struct super_block *exp_sb(struct svc_export *exp)
{
return exp->ex_path.dentry->d_sb;
}
static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
{
switch (fsid_type) {
case FSID_DEV:
if (!old_valid_dev(exp_sb(exp)->s_dev))
return false;
fallthrough;
case FSID_MAJOR_MINOR:
case FSID_ENCODE_DEV:
return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
case FSID_NUM:
return exp->ex_flags & NFSEXP_FSID;
case FSID_UUID8:
case FSID_UUID16:
if (!is_root_export(exp))
return false;
fallthrough;
case FSID_UUID4_INUM:
case FSID_UUID16_INUM:
return exp->ex_uuid != NULL;
}
return true;
}
static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
{
u8 version;
u8 fsid_type;
retry:
version = 1;
if (ref_fh && ref_fh->fh_export == exp) {
version = ref_fh->fh_handle.fh_version;
fsid_type = ref_fh->fh_handle.fh_fsid_type;
ref_fh = NULL;
switch (version) {
case 0xca:
fsid_type = FSID_DEV;
break;
case 1:
break;
default:
goto retry;
}
/*
* As the fsid -> filesystem mapping was guided by
* user-space, there is no guarantee that the filesystem
* actually supports that fsid type. If it doesn't we
* loop around again without ref_fh set.
*/
if (!fsid_type_ok_for_exp(fsid_type, exp))
goto retry;
} else if (exp->ex_flags & NFSEXP_FSID) {
fsid_type = FSID_NUM;
} else if (exp->ex_uuid) {
if (fhp->fh_maxsize >= 64) {
if (is_root_export(exp))
fsid_type = FSID_UUID16;
else
fsid_type = FSID_UUID16_INUM;
} else {
if (is_root_export(exp))
fsid_type = FSID_UUID8;
else
fsid_type = FSID_UUID4_INUM;
}
} else if (!old_valid_dev(exp_sb(exp)->s_dev))
/* for newer device numbers, we must use a newer fsid format */
fsid_type = FSID_ENCODE_DEV;
else
fsid_type = FSID_DEV;
fhp->fh_handle.fh_version = version;
if (version)
fhp->fh_handle.fh_fsid_type = fsid_type;
}
__be32
fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
struct svc_fh *ref_fh)
{
/* ref_fh is a reference file handle.
* if it is non-null and for the same filesystem, then we should compose
* a filehandle which is of the same version, where possible.
*/
struct inode * inode = d_inode(dentry);
dev_t ex_dev = exp_sb(exp)->s_dev;
dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %pd2, ino=%ld)\n",
MAJOR(ex_dev), MINOR(ex_dev),
(long) d_inode(exp->ex_path.dentry)->i_ino,
dentry,
(inode ? inode->i_ino : 0));
/* Choose filehandle version and fsid type based on
* the reference filehandle (if it is in the same export)
* or the export options.
*/
set_version_and_fsid_type(fhp, exp, ref_fh);
/* If we have a ref_fh, then copy the fh_no_wcc setting from it. */
fhp->fh_no_wcc = ref_fh ? ref_fh->fh_no_wcc : false;
if (ref_fh == fhp)
fh_put(ref_fh);
if (fhp->fh_dentry) {
printk(KERN_ERR "fh_compose: fh %pd2 not initialized!\n",
dentry);
}
if (fhp->fh_maxsize < NFS_FHSIZE)
printk(KERN_ERR "fh_compose: called with maxsize %d! %pd2\n",
fhp->fh_maxsize,
dentry);
fhp->fh_dentry = dget(dentry); /* our internal copy */
fhp->fh_export = exp_get(exp);
fhp->fh_handle.fh_size =
key_len(fhp->fh_handle.fh_fsid_type) + 4;
fhp->fh_handle.fh_auth_type = 0;
mk_fsid(fhp->fh_handle.fh_fsid_type,
fhp->fh_handle.fh_fsid,
ex_dev,
d_inode(exp->ex_path.dentry)->i_ino,
exp->ex_fsid, exp->ex_uuid);
if (inode)
_fh_update(fhp, exp, dentry);
if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID) {
fh_put(fhp);
return nfserr_opnotsupp;
}
return 0;
}
/*
* Update file handle information after changing a dentry.
* This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
*/
__be32
fh_update(struct svc_fh *fhp)
{
struct dentry *dentry;
if (!fhp->fh_dentry)
goto out_bad;
dentry = fhp->fh_dentry;
if (d_really_is_negative(dentry))
goto out_negative;
if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
return 0;
_fh_update(fhp, fhp->fh_export, dentry);
if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID)
return nfserr_opnotsupp;
return 0;
out_bad:
printk(KERN_ERR "fh_update: fh not verified!\n");
return nfserr_serverfault;
out_negative:
printk(KERN_ERR "fh_update: %pd2 still negative!\n",
dentry);
return nfserr_serverfault;
}
/**
* fh_fill_pre_attrs - Fill in pre-op attributes
* @fhp: file handle to be updated
*
*/
void fh_fill_pre_attrs(struct svc_fh *fhp)
{
bool v4 = (fhp->fh_maxsize == NFS4_FHSIZE);
struct inode *inode;
struct kstat stat;
__be32 err;
if (fhp->fh_no_wcc || fhp->fh_pre_saved)
return;
inode = d_inode(fhp->fh_dentry);
err = fh_getattr(fhp, &stat);
if (err) {
/* Grab the times from inode anyway */
stat.mtime = inode->i_mtime;
stat.ctime = inode->i_ctime;
stat.size = inode->i_size;
if (v4 && IS_I_VERSION(inode)) {
stat.change_cookie = inode_query_iversion(inode);
stat.result_mask |= STATX_CHANGE_COOKIE;
}
}
if (v4)
fhp->fh_pre_change = nfsd4_change_attribute(&stat, inode);
fhp->fh_pre_mtime = stat.mtime;
fhp->fh_pre_ctime = stat.ctime;
fhp->fh_pre_size = stat.size;
fhp->fh_pre_saved = true;
}
/**
* fh_fill_post_attrs - Fill in post-op attributes
* @fhp: file handle to be updated
*
*/
void fh_fill_post_attrs(struct svc_fh *fhp)
{
bool v4 = (fhp->fh_maxsize == NFS4_FHSIZE);
struct inode *inode = d_inode(fhp->fh_dentry);
__be32 err;
if (fhp->fh_no_wcc)
return;
if (fhp->fh_post_saved)
printk("nfsd: inode locked twice during operation.\n");
err = fh_getattr(fhp, &fhp->fh_post_attr);
if (err) {
fhp->fh_post_saved = false;
fhp->fh_post_attr.ctime = inode->i_ctime;
if (v4 && IS_I_VERSION(inode)) {
fhp->fh_post_attr.change_cookie = inode_query_iversion(inode);
fhp->fh_post_attr.result_mask |= STATX_CHANGE_COOKIE;
}
} else
fhp->fh_post_saved = true;
if (v4)
fhp->fh_post_change =
nfsd4_change_attribute(&fhp->fh_post_attr, inode);
}
/**
* fh_fill_both_attrs - Fill pre-op and post-op attributes
* @fhp: file handle to be updated
*
* This is used when the directory wasn't changed, but wcc attributes
* are needed anyway.
*/
void fh_fill_both_attrs(struct svc_fh *fhp)
{
fh_fill_post_attrs(fhp);
if (!fhp->fh_post_saved)
return;
fhp->fh_pre_change = fhp->fh_post_change;
fhp->fh_pre_mtime = fhp->fh_post_attr.mtime;
fhp->fh_pre_ctime = fhp->fh_post_attr.ctime;
fhp->fh_pre_size = fhp->fh_post_attr.size;
fhp->fh_pre_saved = true;
}
/*
* Release a file handle.
*/
void
fh_put(struct svc_fh *fhp)
{
struct dentry * dentry = fhp->fh_dentry;
struct svc_export * exp = fhp->fh_export;
if (dentry) {
fhp->fh_dentry = NULL;
dput(dentry);
fh_clear_pre_post_attrs(fhp);
}
fh_drop_write(fhp);
if (exp) {
exp_put(exp);
fhp->fh_export = NULL;
}
fhp->fh_no_wcc = false;
return;
}
/*
* Shorthand for dprintk()'s
*/
char * SVCFH_fmt(struct svc_fh *fhp)
{
struct knfsd_fh *fh = &fhp->fh_handle;
static char buf[2+1+1+64*3+1];
if (fh->fh_size < 0 || fh->fh_size> 64)
return "bad-fh";
sprintf(buf, "%d: %*ph", fh->fh_size, fh->fh_size, fh->fh_raw);
return buf;
}
enum fsid_source fsid_source(const struct svc_fh *fhp)
{
if (fhp->fh_handle.fh_version != 1)
return FSIDSOURCE_DEV;
switch(fhp->fh_handle.fh_fsid_type) {
case FSID_DEV:
case FSID_ENCODE_DEV:
case FSID_MAJOR_MINOR:
if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
return FSIDSOURCE_DEV;
break;
case FSID_NUM:
if (fhp->fh_export->ex_flags & NFSEXP_FSID)
return FSIDSOURCE_FSID;
break;
default:
break;
}
/* either a UUID type filehandle, or the filehandle doesn't
* match the export.
*/
if (fhp->fh_export->ex_flags & NFSEXP_FSID)
return FSIDSOURCE_FSID;
if (fhp->fh_export->ex_uuid)
return FSIDSOURCE_UUID;
return FSIDSOURCE_DEV;
}
/*
* We could use i_version alone as the change attribute. However, i_version
* can go backwards on a regular file after an unclean shutdown. 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. If the filesystem
* advertises STATX_ATTR_CHANGE_MONOTONIC, then this mitigation is not
* needed.
*
* We only need to do this for regular files as well. For directories, we
* assume that the new change attr is always logged to stable storage in some
* fashion before the results can be seen.
*/
u64 nfsd4_change_attribute(struct kstat *stat, struct inode *inode)
{
u64 chattr;
if (stat->result_mask & STATX_CHANGE_COOKIE) {
chattr = stat->change_cookie;
if (S_ISREG(inode->i_mode) &&
!(stat->attributes & STATX_ATTR_CHANGE_MONOTONIC)) {
chattr += (u64)stat->ctime.tv_sec << 30;
chattr += stat->ctime.tv_nsec;
}
} else {
chattr = time_to_chattr(&stat->ctime);
}
return chattr;
}