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vfs.c
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// SPDX-License-Identifier: GPL-2.0
/*
* File operations used by nfsd. Some of these have been ripped from
* other parts of the kernel because they weren't exported, others
* are partial duplicates with added or changed functionality.
*
* Note that several functions dget() the dentry upon which they want
* to act, most notably those that create directory entries. Response
* dentry's are dput()'d if necessary in the release callback.
* So if you notice code paths that apparently fail to dput() the
* dentry, don't worry--they have been taken care of.
*
* Copyright (C) 1995-1999 Olaf Kirch <[email protected]>
* Zerocpy NFS support (C) 2002 Hirokazu Takahashi <[email protected]>
*/
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/splice.h>
#include <linux/falloc.h>
#include <linux/fcntl.h>
#include <linux/namei.h>
#include <linux/delay.h>
#include <linux/fsnotify.h>
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
#include <linux/jhash.h>
#include <linux/ima.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/exportfs.h>
#include <linux/writeback.h>
#include <linux/security.h>
#include "xdr3.h"
#ifdef CONFIG_NFSD_V4
#include "../internal.h"
#include "acl.h"
#include "idmap.h"
#include "xdr4.h"
#endif /* CONFIG_NFSD_V4 */
#include "nfsd.h"
#include "vfs.h"
#include "filecache.h"
#include "trace.h"
#define NFSDDBG_FACILITY NFSDDBG_FILEOP
/**
* nfserrno - Map Linux errnos to NFS errnos
* @errno: POSIX(-ish) error code to be mapped
*
* Returns the appropriate (net-endian) nfserr_* (or nfs_ok if errno is 0). If
* it's an error we don't expect, log it once and return nfserr_io.
*/
__be32
nfserrno (int errno)
{
static struct {
__be32 nfserr;
int syserr;
} nfs_errtbl[] = {
{ nfs_ok, 0 },
{ nfserr_perm, -EPERM },
{ nfserr_noent, -ENOENT },
{ nfserr_io, -EIO },
{ nfserr_nxio, -ENXIO },
{ nfserr_fbig, -E2BIG },
{ nfserr_stale, -EBADF },
{ nfserr_acces, -EACCES },
{ nfserr_exist, -EEXIST },
{ nfserr_xdev, -EXDEV },
{ nfserr_mlink, -EMLINK },
{ nfserr_nodev, -ENODEV },
{ nfserr_notdir, -ENOTDIR },
{ nfserr_isdir, -EISDIR },
{ nfserr_inval, -EINVAL },
{ nfserr_fbig, -EFBIG },
{ nfserr_nospc, -ENOSPC },
{ nfserr_rofs, -EROFS },
{ nfserr_mlink, -EMLINK },
{ nfserr_nametoolong, -ENAMETOOLONG },
{ nfserr_notempty, -ENOTEMPTY },
{ nfserr_dquot, -EDQUOT },
{ nfserr_stale, -ESTALE },
{ nfserr_jukebox, -ETIMEDOUT },
{ nfserr_jukebox, -ERESTARTSYS },
{ nfserr_jukebox, -EAGAIN },
{ nfserr_jukebox, -EWOULDBLOCK },
{ nfserr_jukebox, -ENOMEM },
{ nfserr_io, -ETXTBSY },
{ nfserr_notsupp, -EOPNOTSUPP },
{ nfserr_toosmall, -ETOOSMALL },
{ nfserr_serverfault, -ESERVERFAULT },
{ nfserr_serverfault, -ENFILE },
{ nfserr_io, -EREMOTEIO },
{ nfserr_stale, -EOPENSTALE },
{ nfserr_io, -EUCLEAN },
{ nfserr_perm, -ENOKEY },
{ nfserr_no_grace, -ENOGRACE},
};
int i;
for (i = 0; i < ARRAY_SIZE(nfs_errtbl); i++) {
if (nfs_errtbl[i].syserr == errno)
return nfs_errtbl[i].nfserr;
}
WARN_ONCE(1, "nfsd: non-standard errno: %d\n", errno);
return nfserr_io;
}
/*
* Called from nfsd_lookup and encode_dirent. Check if we have crossed
* a mount point.
* Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
* or nfs_ok having possibly changed *dpp and *expp
*/
int
nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
struct svc_export **expp)
{
struct svc_export *exp = *expp, *exp2 = NULL;
struct dentry *dentry = *dpp;
struct path path = {.mnt = mntget(exp->ex_path.mnt),
.dentry = dget(dentry)};
unsigned int follow_flags = 0;
int err = 0;
if (exp->ex_flags & NFSEXP_CROSSMOUNT)
follow_flags = LOOKUP_AUTOMOUNT;
err = follow_down(&path, follow_flags);
if (err < 0)
goto out;
if (path.mnt == exp->ex_path.mnt && path.dentry == dentry &&
nfsd_mountpoint(dentry, exp) == 2) {
/* This is only a mountpoint in some other namespace */
path_put(&path);
goto out;
}
exp2 = rqst_exp_get_by_name(rqstp, &path);
if (IS_ERR(exp2)) {
err = PTR_ERR(exp2);
/*
* We normally allow NFS clients to continue
* "underneath" a mountpoint that is not exported.
* The exception is V4ROOT, where no traversal is ever
* allowed without an explicit export of the new
* directory.
*/
if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
err = 0;
path_put(&path);
goto out;
}
if (nfsd_v4client(rqstp) ||
(exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
/* successfully crossed mount point */
/*
* This is subtle: path.dentry is *not* on path.mnt
* at this point. The only reason we are safe is that
* original mnt is pinned down by exp, so we should
* put path *before* putting exp
*/
*dpp = path.dentry;
path.dentry = dentry;
*expp = exp2;
exp2 = exp;
}
path_put(&path);
exp_put(exp2);
out:
return err;
}
static void follow_to_parent(struct path *path)
{
struct dentry *dp;
while (path->dentry == path->mnt->mnt_root && follow_up(path))
;
dp = dget_parent(path->dentry);
dput(path->dentry);
path->dentry = dp;
}
static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
{
struct svc_export *exp2;
struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
.dentry = dget(dparent)};
follow_to_parent(&path);
exp2 = rqst_exp_parent(rqstp, &path);
if (PTR_ERR(exp2) == -ENOENT) {
*dentryp = dget(dparent);
} else if (IS_ERR(exp2)) {
path_put(&path);
return PTR_ERR(exp2);
} else {
*dentryp = dget(path.dentry);
exp_put(*exp);
*exp = exp2;
}
path_put(&path);
return 0;
}
/*
* For nfsd purposes, we treat V4ROOT exports as though there was an
* export at *every* directory.
* We return:
* '1' if this dentry *must* be an export point,
* '2' if it might be, if there is really a mount here, and
* '0' if there is no chance of an export point here.
*/
int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
{
if (!d_inode(dentry))
return 0;
if (exp->ex_flags & NFSEXP_V4ROOT)
return 1;
if (nfsd4_is_junction(dentry))
return 1;
if (d_managed(dentry))
/*
* Might only be a mountpoint in a different namespace,
* but we need to check.
*/
return 2;
return 0;
}
__be32
nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
const char *name, unsigned int len,
struct svc_export **exp_ret, struct dentry **dentry_ret)
{
struct svc_export *exp;
struct dentry *dparent;
struct dentry *dentry;
int host_err;
dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
dparent = fhp->fh_dentry;
exp = exp_get(fhp->fh_export);
/* Lookup the name, but don't follow links */
if (isdotent(name, len)) {
if (len==1)
dentry = dget(dparent);
else if (dparent != exp->ex_path.dentry)
dentry = dget_parent(dparent);
else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
dentry = dget(dparent); /* .. == . just like at / */
else {
/* checking mountpoint crossing is very different when stepping up */
host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
if (host_err)
goto out_nfserr;
}
} else {
dentry = lookup_one_len_unlocked(name, dparent, len);
host_err = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_nfserr;
if (nfsd_mountpoint(dentry, exp)) {
host_err = nfsd_cross_mnt(rqstp, &dentry, &exp);
if (host_err) {
dput(dentry);
goto out_nfserr;
}
}
}
*dentry_ret = dentry;
*exp_ret = exp;
return 0;
out_nfserr:
exp_put(exp);
return nfserrno(host_err);
}
/**
* nfsd_lookup - look up a single path component for nfsd
*
* @rqstp: the request context
* @fhp: the file handle of the directory
* @name: the component name, or %NULL to look up parent
* @len: length of name to examine
* @resfh: pointer to pre-initialised filehandle to hold result.
*
* Look up one component of a pathname.
* N.B. After this call _both_ fhp and resfh need an fh_put
*
* If the lookup would cross a mountpoint, and the mounted filesystem
* is exported to the client with NFSEXP_NOHIDE, then the lookup is
* accepted as it stands and the mounted directory is
* returned. Otherwise the covered directory is returned.
* NOTE: this mountpoint crossing is not supported properly by all
* clients and is explicitly disallowed for NFSv3
*
*/
__be32
nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
unsigned int len, struct svc_fh *resfh)
{
struct svc_export *exp;
struct dentry *dentry;
__be32 err;
err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
if (err)
return err;
err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
if (err)
return err;
err = check_nfsd_access(exp, rqstp);
if (err)
goto out;
/*
* Note: we compose the file handle now, but as the
* dentry may be negative, it may need to be updated.
*/
err = fh_compose(resfh, exp, dentry, fhp);
if (!err && d_really_is_negative(dentry))
err = nfserr_noent;
out:
dput(dentry);
exp_put(exp);
return err;
}
/*
* Commit metadata changes to stable storage.
*/
static int
commit_inode_metadata(struct inode *inode)
{
const struct export_operations *export_ops = inode->i_sb->s_export_op;
if (export_ops->commit_metadata)
return export_ops->commit_metadata(inode);
return sync_inode_metadata(inode, 1);
}
static int
commit_metadata(struct svc_fh *fhp)
{
struct inode *inode = d_inode(fhp->fh_dentry);
if (!EX_ISSYNC(fhp->fh_export))
return 0;
return commit_inode_metadata(inode);
}
/*
* Go over the attributes and take care of the small differences between
* NFS semantics and what Linux expects.
*/
static void
nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
{
/* Ignore mode updates on symlinks */
if (S_ISLNK(inode->i_mode))
iap->ia_valid &= ~ATTR_MODE;
/* sanitize the mode change */
if (iap->ia_valid & ATTR_MODE) {
iap->ia_mode &= S_IALLUGO;
iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
}
/* Revoke setuid/setgid on chown */
if (!S_ISDIR(inode->i_mode) &&
((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) {
iap->ia_valid |= ATTR_KILL_PRIV;
if (iap->ia_valid & ATTR_MODE) {
/* we're setting mode too, just clear the s*id bits */
iap->ia_mode &= ~S_ISUID;
if (iap->ia_mode & S_IXGRP)
iap->ia_mode &= ~S_ISGID;
} else {
/* set ATTR_KILL_* bits and let VFS handle it */
iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
}
}
}
static __be32
nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct iattr *iap)
{
struct inode *inode = d_inode(fhp->fh_dentry);
if (iap->ia_size < inode->i_size) {
__be32 err;
err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
if (err)
return err;
}
return nfserrno(get_write_access(inode));
}
static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap)
{
int host_err;
if (iap->ia_valid & ATTR_SIZE) {
/*
* RFC5661, Section 18.30.4:
* Changing the size of a file with SETATTR indirectly
* changes the time_modify and change attributes.
*
* (and similar for the older RFCs)
*/
struct iattr size_attr = {
.ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME,
.ia_size = iap->ia_size,
};
if (iap->ia_size < 0)
return -EFBIG;
host_err = notify_change(&nop_mnt_idmap, dentry, &size_attr, NULL);
if (host_err)
return host_err;
iap->ia_valid &= ~ATTR_SIZE;
/*
* Avoid the additional setattr call below if the only other
* attribute that the client sends is the mtime, as we update
* it as part of the size change above.
*/
if ((iap->ia_valid & ~ATTR_MTIME) == 0)
return 0;
}
if (!iap->ia_valid)
return 0;
iap->ia_valid |= ATTR_CTIME;
return notify_change(&nop_mnt_idmap, dentry, iap, NULL);
}
/**
* nfsd_setattr - Set various file attributes.
* @rqstp: controlling RPC transaction
* @fhp: filehandle of target
* @attr: attributes to set
* @check_guard: set to 1 if guardtime is a valid timestamp
* @guardtime: do not act if ctime.tv_sec does not match this timestamp
*
* This call may adjust the contents of @attr (in particular, this
* call may change the bits in the na_iattr.ia_valid field).
*
* Returns nfs_ok on success, otherwise an NFS status code is
* returned. Caller must release @fhp by calling fh_put in either
* case.
*/
__be32
nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct nfsd_attrs *attr,
int check_guard, time64_t guardtime)
{
struct dentry *dentry;
struct inode *inode;
struct iattr *iap = attr->na_iattr;
int accmode = NFSD_MAY_SATTR;
umode_t ftype = 0;
__be32 err;
int host_err;
bool get_write_count;
bool size_change = (iap->ia_valid & ATTR_SIZE);
int retries;
if (iap->ia_valid & ATTR_SIZE) {
accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
ftype = S_IFREG;
}
/*
* If utimes(2) and friends are called with times not NULL, we should
* not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission
* will return EACCES, when the caller's effective UID does not match
* the owner of the file, and the caller is not privileged. In this
* situation, we should return EPERM(notify_change will return this).
*/
if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) {
accmode |= NFSD_MAY_OWNER_OVERRIDE;
if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET)))
accmode |= NFSD_MAY_WRITE;
}
/* Callers that do fh_verify should do the fh_want_write: */
get_write_count = !fhp->fh_dentry;
/* Get inode */
err = fh_verify(rqstp, fhp, ftype, accmode);
if (err)
return err;
if (get_write_count) {
host_err = fh_want_write(fhp);
if (host_err)
goto out;
}
dentry = fhp->fh_dentry;
inode = d_inode(dentry);
nfsd_sanitize_attrs(inode, iap);
if (check_guard && guardtime != inode->i_ctime.tv_sec)
return nfserr_notsync;
/*
* The size case is special, it changes the file in addition to the
* attributes, and file systems don't expect it to be mixed with
* "random" attribute changes. We thus split out the size change
* into a separate call to ->setattr, and do the rest as a separate
* setattr call.
*/
if (size_change) {
err = nfsd_get_write_access(rqstp, fhp, iap);
if (err)
return err;
}
inode_lock(inode);
for (retries = 1;;) {
host_err = __nfsd_setattr(dentry, iap);
if (host_err != -EAGAIN || !retries--)
break;
if (!nfsd_wait_for_delegreturn(rqstp, inode))
break;
}
if (attr->na_seclabel && attr->na_seclabel->len)
attr->na_labelerr = security_inode_setsecctx(dentry,
attr->na_seclabel->data, attr->na_seclabel->len);
if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && attr->na_pacl)
attr->na_aclerr = set_posix_acl(&nop_mnt_idmap,
dentry, ACL_TYPE_ACCESS,
attr->na_pacl);
if (IS_ENABLED(CONFIG_FS_POSIX_ACL) &&
!attr->na_aclerr && attr->na_dpacl && S_ISDIR(inode->i_mode))
attr->na_aclerr = set_posix_acl(&nop_mnt_idmap,
dentry, ACL_TYPE_DEFAULT,
attr->na_dpacl);
inode_unlock(inode);
if (size_change)
put_write_access(inode);
out:
if (!host_err)
host_err = commit_metadata(fhp);
return nfserrno(host_err);
}
#if defined(CONFIG_NFSD_V4)
/*
* NFS junction information is stored in an extended attribute.
*/
#define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs"
/**
* nfsd4_is_junction - Test if an object could be an NFS junction
*
* @dentry: object to test
*
* Returns 1 if "dentry" appears to contain NFS junction information.
* Otherwise 0 is returned.
*/
int nfsd4_is_junction(struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
if (inode == NULL)
return 0;
if (inode->i_mode & S_IXUGO)
return 0;
if (!(inode->i_mode & S_ISVTX))
return 0;
if (vfs_getxattr(&nop_mnt_idmap, dentry, NFSD_JUNCTION_XATTR_NAME,
NULL, 0) <= 0)
return 0;
return 1;
}
static struct nfsd4_compound_state *nfsd4_get_cstate(struct svc_rqst *rqstp)
{
return &((struct nfsd4_compoundres *)rqstp->rq_resp)->cstate;
}
__be32 nfsd4_clone_file_range(struct svc_rqst *rqstp,
struct nfsd_file *nf_src, u64 src_pos,
struct nfsd_file *nf_dst, u64 dst_pos,
u64 count, bool sync)
{
struct file *src = nf_src->nf_file;
struct file *dst = nf_dst->nf_file;
errseq_t since;
loff_t cloned;
__be32 ret = 0;
since = READ_ONCE(dst->f_wb_err);
cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
if (cloned < 0) {
ret = nfserrno(cloned);
goto out_err;
}
if (count && cloned != count) {
ret = nfserrno(-EINVAL);
goto out_err;
}
if (sync) {
loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX;
int status = vfs_fsync_range(dst, dst_pos, dst_end, 0);
if (!status)
status = filemap_check_wb_err(dst->f_mapping, since);
if (!status)
status = commit_inode_metadata(file_inode(src));
if (status < 0) {
struct nfsd_net *nn = net_generic(nf_dst->nf_net,
nfsd_net_id);
trace_nfsd_clone_file_range_err(rqstp,
&nfsd4_get_cstate(rqstp)->save_fh,
src_pos,
&nfsd4_get_cstate(rqstp)->current_fh,
dst_pos,
count, status);
nfsd_reset_write_verifier(nn);
trace_nfsd_writeverf_reset(nn, rqstp, status);
ret = nfserrno(status);
}
}
out_err:
return ret;
}
ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
u64 dst_pos, u64 count)
{
ssize_t ret;
/*
* Limit copy to 4MB to prevent indefinitely blocking an nfsd
* thread and client rpc slot. The choice of 4MB is somewhat
* arbitrary. We might instead base this on r/wsize, or make it
* tunable, or use a time instead of a byte limit, or implement
* asynchronous copy. In theory a client could also recognize a
* limit like this and pipeline multiple COPY requests.
*/
count = min_t(u64, count, 1 << 22);
ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
if (ret == -EOPNOTSUPP || ret == -EXDEV)
ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count,
COPY_FILE_SPLICE);
return ret;
}
__be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct file *file, loff_t offset, loff_t len,
int flags)
{
int error;
if (!S_ISREG(file_inode(file)->i_mode))
return nfserr_inval;
error = vfs_fallocate(file, flags, offset, len);
if (!error)
error = commit_metadata(fhp);
return nfserrno(error);
}
#endif /* defined(CONFIG_NFSD_V4) */
/*
* Check server access rights to a file system object
*/
struct accessmap {
u32 access;
int how;
};
static struct accessmap nfs3_regaccess[] = {
{ NFS3_ACCESS_READ, NFSD_MAY_READ },
{ NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
{ NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
{ NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE },
#ifdef CONFIG_NFSD_V4
{ NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
{ NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
{ NFS4_ACCESS_XALIST, NFSD_MAY_READ },
#endif
{ 0, 0 }
};
static struct accessmap nfs3_diraccess[] = {
{ NFS3_ACCESS_READ, NFSD_MAY_READ },
{ NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC },
{ NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
{ NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE },
{ NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE },
#ifdef CONFIG_NFSD_V4
{ NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
{ NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
{ NFS4_ACCESS_XALIST, NFSD_MAY_READ },
#endif
{ 0, 0 }
};
static struct accessmap nfs3_anyaccess[] = {
/* Some clients - Solaris 2.6 at least, make an access call
* to the server to check for access for things like /dev/null
* (which really, the server doesn't care about). So
* We provide simple access checking for them, looking
* mainly at mode bits, and we make sure to ignore read-only
* filesystem checks
*/
{ NFS3_ACCESS_READ, NFSD_MAY_READ },
{ NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
{ NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
{ NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
{ 0, 0 }
};
__be32
nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
{
struct accessmap *map;
struct svc_export *export;
struct dentry *dentry;
u32 query, result = 0, sresult = 0;
__be32 error;
error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
if (error)
goto out;
export = fhp->fh_export;
dentry = fhp->fh_dentry;
if (d_is_reg(dentry))
map = nfs3_regaccess;
else if (d_is_dir(dentry))
map = nfs3_diraccess;
else
map = nfs3_anyaccess;
query = *access;
for (; map->access; map++) {
if (map->access & query) {
__be32 err2;
sresult |= map->access;
err2 = nfsd_permission(rqstp, export, dentry, map->how);
switch (err2) {
case nfs_ok:
result |= map->access;
break;
/* the following error codes just mean the access was not allowed,
* rather than an error occurred */
case nfserr_rofs:
case nfserr_acces:
case nfserr_perm:
/* simply don't "or" in the access bit. */
break;
default:
error = err2;
goto out;
}
}
}
*access = result;
if (supported)
*supported = sresult;
out:
return error;
}
int nfsd_open_break_lease(struct inode *inode, int access)
{
unsigned int mode;
if (access & NFSD_MAY_NOT_BREAK_LEASE)
return 0;
mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
return break_lease(inode, mode | O_NONBLOCK);
}
/*
* Open an existing file or directory.
* The may_flags argument indicates the type of open (read/write/lock)
* and additional flags.
* N.B. After this call fhp needs an fh_put
*/
static __be32
__nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
int may_flags, struct file **filp)
{
struct path path;
struct inode *inode;
struct file *file;
int flags = O_RDONLY|O_LARGEFILE;
__be32 err;
int host_err = 0;
path.mnt = fhp->fh_export->ex_path.mnt;
path.dentry = fhp->fh_dentry;
inode = d_inode(path.dentry);
err = nfserr_perm;
if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
goto out;
if (!inode->i_fop)
goto out;
host_err = nfsd_open_break_lease(inode, may_flags);
if (host_err) /* NOMEM or WOULDBLOCK */
goto out_nfserr;
if (may_flags & NFSD_MAY_WRITE) {
if (may_flags & NFSD_MAY_READ)
flags = O_RDWR|O_LARGEFILE;
else
flags = O_WRONLY|O_LARGEFILE;
}
file = dentry_open(&path, flags, current_cred());
if (IS_ERR(file)) {
host_err = PTR_ERR(file);
goto out_nfserr;
}
host_err = ima_file_check(file, may_flags);
if (host_err) {
fput(file);
goto out_nfserr;
}
if (may_flags & NFSD_MAY_64BIT_COOKIE)
file->f_mode |= FMODE_64BITHASH;
else
file->f_mode |= FMODE_32BITHASH;
*filp = file;
out_nfserr:
err = nfserrno(host_err);
out:
return err;
}
__be32
nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
int may_flags, struct file **filp)
{
__be32 err;
bool retried = false;
validate_process_creds();
/*
* If we get here, then the client has already done an "open",
* and (hopefully) checked permission - so allow OWNER_OVERRIDE
* in case a chmod has now revoked permission.
*
* Arguably we should also allow the owner override for
* directories, but we never have and it doesn't seem to have
* caused anyone a problem. If we were to change this, note
* also that our filldir callbacks would need a variant of
* lookup_one_len that doesn't check permissions.
*/
if (type == S_IFREG)
may_flags |= NFSD_MAY_OWNER_OVERRIDE;
retry:
err = fh_verify(rqstp, fhp, type, may_flags);
if (!err) {
err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
if (err == nfserr_stale && !retried) {
retried = true;
fh_put(fhp);
goto retry;
}
}
validate_process_creds();
return err;
}
/**
* nfsd_open_verified - Open a regular file for the filecache
* @rqstp: RPC request
* @fhp: NFS filehandle of the file to open
* @may_flags: internal permission flags
* @filp: OUT: open "struct file *"
*
* Returns an nfsstat value in network byte order.
*/
__be32
nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, int may_flags,
struct file **filp)
{
__be32 err;
validate_process_creds();
err = __nfsd_open(rqstp, fhp, S_IFREG, may_flags, filp);
validate_process_creds();
return err;
}
/*
* Grab and keep cached pages associated with a file in the svc_rqst
* so that they can be passed to the network sendmsg/sendpage routines
* directly. They will be released after the sending has completed.
*/
static int
nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
struct splice_desc *sd)
{
struct svc_rqst *rqstp = sd->u.data;
struct page *page = buf->page; // may be a compound one
unsigned offset = buf->offset;
struct page *last_page;
last_page = page + (offset + sd->len - 1) / PAGE_SIZE;
for (page += offset / PAGE_SIZE; page <= last_page; page++)
svc_rqst_replace_page(rqstp, page);
if (rqstp->rq_res.page_len == 0) // first call
rqstp->rq_res.page_base = offset % PAGE_SIZE;
rqstp->rq_res.page_len += sd->len;
return sd->len;
}
static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
struct splice_desc *sd)
{
return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
}
static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len,
size_t expected)
{
if (expected != 0 && len == 0)
return 1;
if (offset+len >= i_size_read(file_inode(file)))
return 1;
return 0;
}
static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct file *file, loff_t offset,
unsigned long *count, u32 *eof, ssize_t host_err)
{
if (host_err >= 0) {
nfsd_stats_io_read_add(fhp->fh_export, host_err);
*eof = nfsd_eof_on_read(file, offset, host_err, *count);
*count = host_err;
fsnotify_access(file);
trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
return 0;
} else {
trace_nfsd_read_err(rqstp, fhp, offset, host_err);
return nfserrno(host_err);
}
}
__be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct file *file, loff_t offset, unsigned long *count,
u32 *eof)
{
struct splice_desc sd = {
.len = 0,
.total_len = *count,
.pos = offset,
.u.data = rqstp,
};
ssize_t host_err;
trace_nfsd_read_splice(rqstp, fhp, offset, *count);
rqstp->rq_next_page = rqstp->rq_respages + 1;
host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);