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4335723e8e
kernel_optimize_test/fs/nfsd/vfs.c
J. Bruce Fields 4335723e8e nfsd4: fix delegation-unlink/rename race 
If a file is unlinked or renamed between the time when we do the local
open and the time when we get the delegation, then we will return to the
client indicating that it holds a delegation even though the file no
longer exists under the name it was open under.

But a client performing an open-by-name, when it is returned a
delegation, must be able to assume that the file is still linked at the
name it was opened under.

So, hold the parent i_mutex for longer to prevent concurrent renames or
unlinks.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-01-27 13:59:16 -05:00

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/*
* 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 <okir@monad.swb.de>
* Zerocpy NFS support (C) 2002 Hirokazu Takahashi <taka@valinux.co.jp>
*/
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/splice.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/slab.h>
#include <asm/uaccess.h>
#include <linux/exportfs.h>
#include <linux/writeback.h>
#include <linux/security.h>
#ifdef CONFIG_NFSD_V3
#include "xdr3.h"
#endif /* CONFIG_NFSD_V3 */
#ifdef CONFIG_NFSD_V4
#include "acl.h"
#include "idmap.h"
#endif /* CONFIG_NFSD_V4 */
#include "nfsd.h"
#include "vfs.h"
#define NFSDDBG_FACILITY NFSDDBG_FILEOP
/*
* This is a cache of readahead params that help us choose the proper
* readahead strategy. Initially, we set all readahead parameters to 0
* and let the VFS handle things.
* If you increase the number of cached files very much, you'll need to
* add a hash table here.
*/
struct raparms {
struct raparms *p_next;
unsigned int p_count;
ino_t p_ino;
dev_t p_dev;
int p_set;
struct file_ra_state p_ra;
unsigned int p_hindex;
};
struct raparm_hbucket {
struct raparms *pb_head;
spinlock_t pb_lock;
} ____cacheline_aligned_in_smp;
#define RAPARM_HASH_BITS 4
#define RAPARM_HASH_SIZE (1<<RAPARM_HASH_BITS)
#define RAPARM_HASH_MASK (RAPARM_HASH_SIZE-1)
static struct raparm_hbucket raparm_hash[RAPARM_HASH_SIZE];
/*
* 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)};
int err = 0;
err = follow_down(&path);
if (err < 0)
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.
*/
int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
{
if (d_mountpoint(dentry))
return 1;
if (nfsd4_is_junction(dentry))
return 1;
if (!(exp->ex_flags & NFSEXP_V4ROOT))
return 0;
return dentry->d_inode != NULL;
}
__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 = fhp->fh_export;
exp_get(exp);
/* 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 {
/*
* In the nfsd4_open() case, this may be held across
* subsequent open and delegation acquisition which may
* need to take the child's i_mutex:
*/
fh_lock_nested(fhp, I_MUTEX_PARENT);
dentry = lookup_one_len(name, dparent, len);
host_err = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_nfserr;
/*
* check if we have crossed a mount point ...
*/
if (nfsd_mountpoint(dentry, exp)) {
if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
dput(dentry);
goto out_nfserr;
}
}
}
*dentry_ret = dentry;
*exp_ret = exp;
return 0;
out_nfserr:
exp_put(exp);
return nfserrno(host_err);
}
/*
* 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
* NeilBrown <neilb@cse.unsw.edu.au>
*/
__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 && !dentry->d_inode)
err = nfserr_noent;
out:
dput(dentry);
exp_put(exp);
return err;
}
/*
* Commit metadata changes to stable storage.
*/
static int
commit_metadata(struct svc_fh *fhp)
{
struct inode *inode = fhp->fh_dentry->d_inode;
const struct export_operations *export_ops = inode->i_sb->s_export_op;
if (!EX_ISSYNC(fhp->fh_export))
return 0;
if (export_ops->commit_metadata)
return export_ops->commit_metadata(inode);
return sync_inode_metadata(inode, 1);
}
/*
* 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)
{
/*
* NFSv2 does not differentiate between "set-[ac]time-to-now"
* which only requires access, and "set-[ac]time-to-X" which
* requires ownership.
* So if it looks like it might be "set both to the same time which
* is close to now", and if inode_change_ok fails, then we
* convert to "set to now" instead of "set to explicit time"
*
* We only call inode_change_ok as the last test as technically
* it is not an interface that we should be using.
*/
#define BOTH_TIME_SET (ATTR_ATIME_SET | ATTR_MTIME_SET)
#define MAX_TOUCH_TIME_ERROR (30*60)
if ((iap->ia_valid & BOTH_TIME_SET) == BOTH_TIME_SET &&
iap->ia_mtime.tv_sec == iap->ia_atime.tv_sec) {
/*
* Looks probable.
*
* Now just make sure time is in the right ballpark.
* Solaris, at least, doesn't seem to care what the time
* request is. We require it be within 30 minutes of now.
*/
time_t delta = iap->ia_atime.tv_sec - get_seconds();
if (delta < 0)
delta = -delta;
if (delta < MAX_TOUCH_TIME_ERROR &&
inode_change_ok(inode, iap) != 0) {
/*
* Turn off ATTR_[AM]TIME_SET but leave ATTR_[AM]TIME.
* This will cause notify_change to set these times
* to "now"
*/
iap->ia_valid &= ~BOTH_TIME_SET;
}
}
/* 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 = fhp->fh_dentry->d_inode;
int host_err;
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;
}
host_err = get_write_access(inode);
if (host_err)
goto out_nfserrno;
host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
if (host_err)
goto out_put_write_access;
return 0;
out_put_write_access:
put_write_access(inode);
out_nfserrno:
return nfserrno(host_err);
}
/*
* Set various file attributes. After this call fhp needs an fh_put.
*/
__be32
nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
int check_guard, time_t guardtime)
{
struct dentry *dentry;
struct inode *inode;
int accmode = NFSD_MAY_SATTR;
umode_t ftype = 0;
__be32 err;
int host_err;
int size_change = 0;
if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
if (iap->ia_valid & ATTR_SIZE)
ftype = S_IFREG;
/* Get inode */
err = fh_verify(rqstp, fhp, ftype, accmode);
if (err)
goto out;
dentry = fhp->fh_dentry;
inode = dentry->d_inode;
/* Ignore any mode updates on symlinks */
if (S_ISLNK(inode->i_mode))
iap->ia_valid &= ~ATTR_MODE;
if (!iap->ia_valid)
goto out;
nfsd_sanitize_attrs(inode, iap);
/*
* The size case is special, it changes the file in addition to the
* attributes.
*/
if (iap->ia_valid & ATTR_SIZE) {
err = nfsd_get_write_access(rqstp, fhp, iap);
if (err)
goto out;
size_change = 1;
}
iap->ia_valid |= ATTR_CTIME;
if (check_guard && guardtime != inode->i_ctime.tv_sec) {
err = nfserr_notsync;
goto out_put_write_access;
}
fh_lock(fhp);
host_err = notify_change(dentry, iap, NULL);
fh_unlock(fhp);
out_put_write_access:
if (size_change)
put_write_access(inode);
if (!err)
commit_metadata(fhp);
out:
return err;
}
#if defined(CONFIG_NFSD_V2_ACL) || \
defined(CONFIG_NFSD_V3_ACL) || \
defined(CONFIG_NFSD_V4)
static ssize_t nfsd_getxattr(struct dentry *dentry, char *key, void **buf)
{
ssize_t buflen;
ssize_t ret;
buflen = vfs_getxattr(dentry, key, NULL, 0);
if (buflen <= 0)
return buflen;
*buf = kmalloc(buflen, GFP_KERNEL);
if (!*buf)
return -ENOMEM;
ret = vfs_getxattr(dentry, key, *buf, buflen);
if (ret < 0)
kfree(*buf);
return ret;
}
#endif
#if defined(CONFIG_NFSD_V4)
static int
set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key)
{
int len;
size_t buflen;
char *buf = NULL;
int error = 0;
buflen = posix_acl_xattr_size(pacl->a_count);
buf = kmalloc(buflen, GFP_KERNEL);
error = -ENOMEM;
if (buf == NULL)
goto out;
len = posix_acl_to_xattr(&init_user_ns, pacl, buf, buflen);
if (len < 0) {
error = len;
goto out;
}
error = vfs_setxattr(dentry, key, buf, len, 0);
out:
kfree(buf);
return error;
}
__be32
nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct nfs4_acl *acl)
{
__be32 error;
int host_error;
struct dentry *dentry;
struct inode *inode;
struct posix_acl *pacl = NULL, *dpacl = NULL;
unsigned int flags = 0;
/* Get inode */
error = fh_verify(rqstp, fhp, 0, NFSD_MAY_SATTR);
if (error)
return error;
dentry = fhp->fh_dentry;
inode = dentry->d_inode;
if (S_ISDIR(inode->i_mode))
flags = NFS4_ACL_DIR;
host_error = nfs4_acl_nfsv4_to_posix(acl, &pacl, &dpacl, flags);
if (host_error == -EINVAL) {
return nfserr_attrnotsupp;
} else if (host_error < 0)
goto out_nfserr;
host_error = set_nfsv4_acl_one(dentry, pacl, POSIX_ACL_XATTR_ACCESS);
if (host_error < 0)
goto out_release;
if (S_ISDIR(inode->i_mode))
host_error = set_nfsv4_acl_one(dentry, dpacl, POSIX_ACL_XATTR_DEFAULT);
out_release:
posix_acl_release(pacl);
posix_acl_release(dpacl);
out_nfserr:
if (host_error == -EOPNOTSUPP)
return nfserr_attrnotsupp;
else
return nfserrno(host_error);
}
static struct posix_acl *
_get_posix_acl(struct dentry *dentry, char *key)
{
void *buf = NULL;
struct posix_acl *pacl = NULL;
int buflen;
buflen = nfsd_getxattr(dentry, key, &buf);
if (!buflen)
buflen = -ENODATA;
if (buflen <= 0)
return ERR_PTR(buflen);
pacl = posix_acl_from_xattr(&init_user_ns, buf, buflen);
kfree(buf);
return pacl;
}
int
nfsd4_get_nfs4_acl(struct svc_rqst *rqstp, struct dentry *dentry, struct nfs4_acl **acl)
{
struct inode *inode = dentry->d_inode;
int error = 0;
struct posix_acl *pacl = NULL, *dpacl = NULL;
unsigned int flags = 0;
pacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_ACCESS);
if (IS_ERR(pacl) && PTR_ERR(pacl) == -ENODATA)
pacl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
if (IS_ERR(pacl)) {
error = PTR_ERR(pacl);
pacl = NULL;
goto out;
}
if (S_ISDIR(inode->i_mode)) {
dpacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_DEFAULT);
if (IS_ERR(dpacl) && PTR_ERR(dpacl) == -ENODATA)
dpacl = NULL;
else if (IS_ERR(dpacl)) {
error = PTR_ERR(dpacl);
dpacl = NULL;
goto out;
}
flags = NFS4_ACL_DIR;
}
*acl = nfs4_acl_posix_to_nfsv4(pacl, dpacl, flags);
if (IS_ERR(*acl)) {
error = PTR_ERR(*acl);
*acl = NULL;
}
out:
posix_acl_release(pacl);
posix_acl_release(dpacl);
return error;
}
/*
* 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 = dentry->d_inode;
if (inode == NULL)
return 0;
if (inode->i_mode & S_IXUGO)
return 0;
if (!(inode->i_mode & S_ISVTX))
return 0;
if (vfs_getxattr(dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0)
return 0;
return 1;
}
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct xdr_netobj *label)
{
__be32 error;
int host_error;
struct dentry *dentry;
error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
if (error)
return error;
dentry = fhp->fh_dentry;
mutex_lock(&dentry->d_inode->i_mutex);
host_error = security_inode_setsecctx(dentry, label->data, label->len);
mutex_unlock(&dentry->d_inode->i_mutex);
return nfserrno(host_error);
}
#else
__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct xdr_netobj *label)
{
return nfserr_notsupp;
}
#endif
#endif /* defined(CONFIG_NFSD_V4) */
#ifdef CONFIG_NFSD_V3
/*
* 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 },
{ 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 },
{ 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 (S_ISREG(dentry->d_inode->i_mode))
map = nfs3_regaccess;
else if (S_ISDIR(dentry->d_inode->i_mode))
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;
}
#endif /* CONFIG_NFSD_V3 */
static 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
*/
__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;
int flags = O_RDONLY|O_LARGEFILE;
__be32 err;
int host_err = 0;
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;
err = fh_verify(rqstp, fhp, type, may_flags);
if (err)
goto out;
path.mnt = fhp->fh_export->ex_path.mnt;
path.dentry = fhp->fh_dentry;
inode = path.dentry->d_inode;
/* Disallow write access to files with the append-only bit set
* or any access when mandatory locking enabled
*/
err = nfserr_perm;
if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
goto out;
/*
* We must ignore files (but only files) which might have mandatory
* locks on them because there is no way to know if the accesser has
* the lock.
*/
if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
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;
}
*filp = dentry_open(&path, flags, current_cred());
if (IS_ERR(*filp)) {
host_err = PTR_ERR(*filp);
*filp = NULL;
} else {
host_err = ima_file_check(*filp, may_flags);
if (may_flags & NFSD_MAY_64BIT_COOKIE)
(*filp)->f_mode |= FMODE_64BITHASH;
else
(*filp)->f_mode |= FMODE_32BITHASH;
}
out_nfserr:
err = nfserrno(host_err);
out:
validate_process_creds();
return err;
}
/*
* Close a file.
*/
void
nfsd_close(struct file *filp)
{
fput(filp);
}
/*
* Obtain the readahead parameters for the file
* specified by (dev, ino).
*/
static inline struct raparms *
nfsd_get_raparms(dev_t dev, ino_t ino)
{
struct raparms *ra, **rap, **frap = NULL;
int depth = 0;
unsigned int hash;
struct raparm_hbucket *rab;
hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK;
rab = &raparm_hash[hash];
spin_lock(&rab->pb_lock);
for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) {
if (ra->p_ino == ino && ra->p_dev == dev)
goto found;
depth++;
if (ra->p_count == 0)
frap = rap;
}
depth = nfsdstats.ra_size;
if (!frap) {
spin_unlock(&rab->pb_lock);
return NULL;
}
rap = frap;
ra = *frap;
ra->p_dev = dev;
ra->p_ino = ino;
ra->p_set = 0;
ra->p_hindex = hash;
found:
if (rap != &rab->pb_head) {
*rap = ra->p_next;
ra->p_next = rab->pb_head;
rab->pb_head = ra;
}
ra->p_count++;
nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++;
spin_unlock(&rab->pb_lock);
return ra;
}
/*
* 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 **pp = rqstp->rq_next_page;
struct page *page = buf->page;
size_t size;
size = sd->len;
if (rqstp->rq_res.page_len == 0) {
get_page(page);
put_page(*rqstp->rq_next_page);
*(rqstp->rq_next_page++) = page;
rqstp->rq_res.page_base = buf->offset;
rqstp->rq_res.page_len = size;
} else if (page != pp[-1]) {
get_page(page);
if (*rqstp->rq_next_page)
put_page(*rqstp->rq_next_page);
*(rqstp->rq_next_page++) = page;
rqstp->rq_res.page_len += size;
} else
rqstp->rq_res.page_len += size;
return size;
}
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 __be32
nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
{
mm_segment_t oldfs;
__be32 err;
int host_err;
err = nfserr_perm;
if (file->f_op->splice_read && rqstp->rq_splice_ok) {
struct splice_desc sd = {
.len = 0,
.total_len = *count,
.pos = offset,
.u.data = rqstp,
};
rqstp->rq_next_page = rqstp->rq_respages + 1;
host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
} else {
oldfs = get_fs();
set_fs(KERNEL_DS);
host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset);
set_fs(oldfs);
}
if (host_err >= 0) {
nfsdstats.io_read += host_err;
*count = host_err;
err = 0;
fsnotify_access(file);
} else
err = nfserrno(host_err);
return err;
}
static void kill_suid(struct dentry *dentry)
{
struct iattr ia;
ia.ia_valid = ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
mutex_lock(&dentry->d_inode->i_mutex);
/*
* Note we call this on write, so notify_change will not
* encounter any conflicting delegations:
*/
notify_change(dentry, &ia, NULL);
mutex_unlock(&dentry->d_inode->i_mutex);
}
/*
* Gathered writes: If another process is currently writing to the file,
* there's a high chance this is another nfsd (triggered by a bulk write
* from a client's biod). Rather than syncing the file with each write
* request, we sleep for 10 msec.
*
* I don't know if this roughly approximates C. Juszak's idea of
* gathered writes, but it's a nice and simple solution (IMHO), and it
* seems to work:-)
*
* Note: we do this only in the NFSv2 case, since v3 and higher have a
* better tool (separate unstable writes and commits) for solving this
* problem.
*/
static int wait_for_concurrent_writes(struct file *file)
{
struct inode *inode = file_inode(file);
static ino_t last_ino;
static dev_t last_dev;
int err = 0;
if (atomic_read(&inode->i_writecount) > 1
|| (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
dprintk("nfsd: write defer %d\n", task_pid_nr(current));
msleep(10);
dprintk("nfsd: write resume %d\n", task_pid_nr(current));
}
if (inode->i_state & I_DIRTY) {
dprintk("nfsd: write sync %d\n", task_pid_nr(current));
err = vfs_fsync(file, 0);
}
last_ino = inode->i_ino;
last_dev = inode->i_sb->s_dev;
return err;
}
static __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 *stablep)
{
struct svc_export *exp;
struct dentry *dentry;
struct inode *inode;
mm_segment_t oldfs;
__be32 err = 0;
int host_err;
int stable = *stablep;
int use_wgather;
loff_t pos = offset;
dentry = file->f_path.dentry;
inode = dentry->d_inode;
exp = fhp->fh_export;
use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
if (!EX_ISSYNC(exp))
stable = 0;
/* Write the data. */
oldfs = get_fs(); set_fs(KERNEL_DS);
host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos);
set_fs(oldfs);
if (host_err < 0)
goto out_nfserr;
*cnt = host_err;
nfsdstats.io_write += host_err;
fsnotify_modify(file);
/* clear setuid/setgid flag after write */
if (inode->i_mode & (S_ISUID | S_ISGID))
kill_suid(dentry);
if (stable) {
if (use_wgather)
host_err = wait_for_concurrent_writes(file);
else
host_err = vfs_fsync_range(file, offset, offset+*cnt, 0);
}
out_nfserr:
dprintk("nfsd: write complete host_err=%d\n", host_err);
if (host_err >= 0)
err = 0;
else
err = nfserrno(host_err);
return err;
}
/*
* Read data from a file. count must contain the requested read count
* on entry. On return, *count contains the number of bytes actually read.
* N.B. After this call fhp needs an fh_put
*/
__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
{
struct file *file;
struct inode *inode;
struct raparms *ra;
__be32 err;
err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file);
if (err)
return err;
inode = file_inode(file);
/* Get readahead parameters */
ra = nfsd_get_raparms(inode->i_sb->s_dev, inode->i_ino);
if (ra && ra->p_set)
file->f_ra = ra->p_ra;
err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
/* Write back readahead params */
if (ra) {
struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex];
spin_lock(&rab->pb_lock);
ra->p_ra = file->f_ra;
ra->p_set = 1;
ra->p_count--;
spin_unlock(&rab->pb_lock);
}
nfsd_close(file);
return err;
}
/* As above, but use the provided file descriptor. */
__be32
nfsd_read_file(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
loff_t offset, struct kvec *vec, int vlen,
unsigned long *count)
{
__be32 err;
if (file) {
err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
NFSD_MAY_READ|NFSD_MAY_OWNER_OVERRIDE);
if (err)
goto out;
err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
} else /* Note file may still be NULL in NFSv4 special stateid case: */
err = nfsd_read(rqstp, fhp, offset, vec, vlen, count);
out:
return err;
}
/*
* Write data to a file.
* The stable flag requests synchronous writes.
* N.B. After this call fhp needs an fh_put
*/
__be32
nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt,
int *stablep)
{
__be32 err = 0;
if (file) {
err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE);
if (err)
goto out;
err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt,
stablep);
} else {
err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file);
if (err)
goto out;
if (cnt)
err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen,
cnt, stablep);
nfsd_close(file);
}
out:
return err;
}
#ifdef CONFIG_NFSD_V3
/*
* Commit all pending writes to stable storage.
*
* Note: we only guarantee that data that lies within the range specified
* by the 'offset' and 'count' parameters will be synced.
*
* Unfortunately we cannot lock the file to make sure we return full WCC
* data to the client, as locking happens lower down in the filesystem.
*/
__be32
nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
loff_t offset, unsigned long count)
{
struct file *file;
loff_t end = LLONG_MAX;
__be32 err = nfserr_inval;
if (offset < 0)
goto out;
if (count != 0) {
end = offset + (loff_t)count - 1;
if (end < offset)
goto out;
}
err = nfsd_open(rqstp, fhp, S_IFREG,
NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file);
if (err)
goto out;
if (EX_ISSYNC(fhp->fh_export)) {
int err2 = vfs_fsync_range(file, offset, end, 0);
if (err2 != -EINVAL)
err = nfserrno(err2);
else
err = nfserr_notsupp;
}
nfsd_close(file);
out:
return err;
}
#endif /* CONFIG_NFSD_V3 */
static __be32
nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
struct iattr *iap)
{
/*
* Mode has already been set earlier in create:
*/
iap->ia_valid &= ~ATTR_MODE;
/*
* Setting uid/gid works only for root. Irix appears to
* send along the gid on create when it tries to implement
* setgid directories via NFS:
*/
if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
if (iap->ia_valid)
return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
return 0;
}
/* HPUX client sometimes creates a file in mode 000, and sets size to 0.
* setting size to 0 may fail for some specific file systems by the permission
* checking which requires WRITE permission but the mode is 000.
* we ignore the resizing(to 0) on the just new created file, since the size is
* 0 after file created.
*
* call this only after vfs_create() is called.
* */
static void
nfsd_check_ignore_resizing(struct iattr *iap)
{
if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
iap->ia_valid &= ~ATTR_SIZE;
}
/*
* Create a file (regular, directory, device, fifo); UNIX sockets
* not yet implemented.
* If the response fh has been verified, the parent directory should
* already be locked. Note that the parent directory is left locked.
*
* N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
*/
__be32
nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
char *fname, int flen, struct iattr *iap,
int type, dev_t rdev, struct svc_fh *resfhp)
{
struct dentry *dentry, *dchild = NULL;
struct inode *dirp;
__be32 err;
__be32 err2;
int host_err;
err = nfserr_perm;
if (!flen)
goto out;
err = nfserr_exist;
if (isdotent(fname, flen))
goto out;
err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
if (err)
goto out;
dentry = fhp->fh_dentry;
dirp = dentry->d_inode;
err = nfserr_notdir;
if (!dirp->i_op->lookup)
goto out;
/*
* Check whether the response file handle has been verified yet.
* If it has, the parent directory should already be locked.
*/
if (!resfhp->fh_dentry) {
host_err = fh_want_write(fhp);
if (host_err)
goto out_nfserr;
/* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */
fh_lock_nested(fhp, I_MUTEX_PARENT);
dchild = lookup_one_len(fname, dentry, flen);
host_err = PTR_ERR(dchild);
if (IS_ERR(dchild))
goto out_nfserr;
err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
if (err)
goto out;
} else {
/* called from nfsd_proc_create */
dchild = dget(resfhp->fh_dentry);
if (!fhp->fh_locked) {
/* not actually possible */
printk(KERN_ERR
"nfsd_create: parent %pd2 not locked!\n",
dentry);
err = nfserr_io;
goto out;
}
}
/*
* Make sure the child dentry is still negative ...
*/
err = nfserr_exist;
if (dchild->d_inode) {
dprintk("nfsd_create: dentry %pd/%pd not negative!\n",
dentry, dchild);
goto out;
}
if (!(iap->ia_valid & ATTR_MODE))
iap->ia_mode = 0;
iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
err = nfserr_inval;
if (!S_ISREG(type) && !S_ISDIR(type) && !special_file(type)) {
printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
type);
goto out;
}
/*
* Get the dir op function pointer.
*/
err = 0;
host_err = 0;
switch (type) {
case S_IFREG:
host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
if (!host_err)
nfsd_check_ignore_resizing(iap);
break;
case S_IFDIR:
host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
break;
case S_IFCHR:
case S_IFBLK:
case S_IFIFO:
case S_IFSOCK:
host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
break;
}
if (host_err < 0)
goto out_nfserr;
err = nfsd_create_setattr(rqstp, resfhp, iap);
/*
* nfsd_setattr already committed the child. Transactional filesystems
* had a chance to commit changes for both parent and child
* simultaneously making the following commit_metadata a noop.
*/
err2 = nfserrno(commit_metadata(fhp));
if (err2)
err = err2;
/*
* Update the file handle to get the new inode info.
*/
if (!err)
err = fh_update(resfhp);
out:
if (dchild && !IS_ERR(dchild))
dput(dchild);
return err;
out_nfserr:
err = nfserrno(host_err);
goto out;
}
#ifdef CONFIG_NFSD_V3
static inline int nfsd_create_is_exclusive(int createmode)
{
return createmode == NFS3_CREATE_EXCLUSIVE
|| createmode == NFS4_CREATE_EXCLUSIVE4_1;
}
/*
* NFSv3 and NFSv4 version of nfsd_create
*/
__be32
do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
char *fname, int flen, struct iattr *iap,
struct svc_fh *resfhp, int createmode, u32 *verifier,
bool *truncp, bool *created)
{
struct dentry *dentry, *dchild = NULL;
struct inode *dirp;
__be32 err;
int host_err;
__u32 v_mtime=0, v_atime=0;
err = nfserr_perm;
if (!flen)
goto out;
err = nfserr_exist;
if (isdotent(fname, flen))
goto out;
if (!(iap->ia_valid & ATTR_MODE))
iap->ia_mode = 0;
err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
if (err)
goto out;
dentry = fhp->fh_dentry;
dirp = dentry->d_inode;
/* Get all the sanity checks out of the way before
* we lock the parent. */
err = nfserr_notdir;
if (!dirp->i_op->lookup)
goto out;
host_err = fh_want_write(fhp);
if (host_err)
goto out_nfserr;
fh_lock_nested(fhp, I_MUTEX_PARENT);
/*
* Compose the response file handle.
*/
dchild = lookup_one_len(fname, dentry, flen);
host_err = PTR_ERR(dchild);
if (IS_ERR(dchild))
goto out_nfserr;
/* If file doesn't exist, check for permissions to create one */
if (!dchild->d_inode) {
err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
if (err)
goto out;
}
err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
if (err)
goto out;
if (nfsd_create_is_exclusive(createmode)) {
/* solaris7 gets confused (bugid 4218508) if these have
* the high bit set, so just clear the high bits. If this is
* ever changed to use different attrs for storing the
* verifier, then do_open_lookup() will also need to be fixed
* accordingly.
*/
v_mtime = verifier[0]&0x7fffffff;
v_atime = verifier[1]&0x7fffffff;
}
if (dchild->d_inode) {
err = 0;
switch (createmode) {
case NFS3_CREATE_UNCHECKED:
if (! S_ISREG(dchild->d_inode->i_mode))
goto out;
else if (truncp) {
/* in nfsv4, we need to treat this case a little
* differently. we don't want to truncate the
* file now; this would be wrong if the OPEN
* fails for some other reason. furthermore,
* if the size is nonzero, we should ignore it
* according to spec!
*/
*truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size;
}
else {
iap->ia_valid &= ATTR_SIZE;
goto set_attr;
}
break;
case NFS3_CREATE_EXCLUSIVE:
if ( dchild->d_inode->i_mtime.tv_sec == v_mtime
&& dchild->d_inode->i_atime.tv_sec == v_atime
&& dchild->d_inode->i_size == 0 ) {
if (created)
*created = 1;
break;
}
case NFS4_CREATE_EXCLUSIVE4_1:
if ( dchild->d_inode->i_mtime.tv_sec == v_mtime
&& dchild->d_inode->i_atime.tv_sec == v_atime
&& dchild->d_inode->i_size == 0 ) {
if (created)
*created = 1;
goto set_attr;
}
/* fallthru */
case NFS3_CREATE_GUARDED:
err = nfserr_exist;
}
fh_drop_write(fhp);
goto out;
}
host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
if (host_err < 0) {
fh_drop_write(fhp);
goto out_nfserr;
}
if (created)
*created = 1;
nfsd_check_ignore_resizing(iap);
if (nfsd_create_is_exclusive(createmode)) {
/* Cram the verifier into atime/mtime */
iap->ia_valid = ATTR_MTIME|ATTR_ATIME
| ATTR_MTIME_SET|ATTR_ATIME_SET;
/* XXX someone who knows this better please fix it for nsec */
iap->ia_mtime.tv_sec = v_mtime;
iap->ia_atime.tv_sec = v_atime;
iap->ia_mtime.tv_nsec = 0;
iap->ia_atime.tv_nsec = 0;
}
set_attr:
err = nfsd_create_setattr(rqstp, resfhp, iap);
/*
* nfsd_setattr already committed the child (and possibly also the parent).
*/
if (!err)
err = nfserrno(commit_metadata(fhp));
/*
* Update the filehandle to get the new inode info.
*/
if (!err)
err = fh_update(resfhp);
out:
fh_unlock(fhp);
if (dchild && !IS_ERR(dchild))
dput(dchild);
fh_drop_write(fhp);
return err;
out_nfserr:
err = nfserrno(host_err);
goto out;
}
#endif /* CONFIG_NFSD_V3 */
/*
* Read a symlink. On entry, *lenp must contain the maximum path length that
* fits into the buffer. On return, it contains the true length.
* N.B. After this call fhp needs an fh_put
*/
__be32
nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
{
struct inode *inode;
mm_segment_t oldfs;
__be32 err;
int host_err;
struct path path;
err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
if (err)
goto out;
path.mnt = fhp->fh_export->ex_path.mnt;
path.dentry = fhp->fh_dentry;
inode = path.dentry->d_inode;
err = nfserr_inval;
if (!inode->i_op->readlink)
goto out;
touch_atime(&path);
/* N.B. Why does this call need a get_fs()??
* Remove the set_fs and watch the fireworks:-) --okir
*/
oldfs = get_fs(); set_fs(KERNEL_DS);
host_err = inode->i_op->readlink(path.dentry, (char __user *)buf, *lenp);
set_fs(oldfs);
if (host_err < 0)
goto out_nfserr;
*lenp = host_err;
err = 0;
out:
return err;
out_nfserr:
err = nfserrno(host_err);
goto out;
}
/*
* Create a symlink and look up its inode
* N.B. After this call _both_ fhp and resfhp need an fh_put
*/
__be32
nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
char *fname, int flen,
char *path, int plen,
struct svc_fh *resfhp,
struct iattr *iap)
{
struct dentry *dentry, *dnew;
__be32 err, cerr;
int host_err;
err = nfserr_noent;
if (!flen || !plen)
goto out;
err = nfserr_exist;
if (isdotent(fname, flen))
goto out;
err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
if (err)
goto out;
host_err = fh_want_write(fhp);
if (host_err)
goto out_nfserr;
fh_lock(fhp);
dentry = fhp->fh_dentry;
dnew = lookup_one_len(fname, dentry, flen);
host_err = PTR_ERR(dnew);
if (IS_ERR(dnew))
goto out_nfserr;
if (unlikely(path[plen] != 0)) {
char *path_alloced = kmalloc(plen+1, GFP_KERNEL);
if (path_alloced == NULL)
host_err = -ENOMEM;
else {
strncpy(path_alloced, path, plen);
path_alloced[plen] = 0;
host_err = vfs_symlink(dentry->d_inode, dnew, path_alloced);
kfree(path_alloced);
}
} else
host_err = vfs_symlink(dentry->d_inode, dnew, path);
err = nfserrno(host_err);
if (!err)
err = nfserrno(commit_metadata(fhp));
fh_unlock(fhp);
fh_drop_write(fhp);
cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
dput(dnew);
if (err==0) err = cerr;
out:
return err;
out_nfserr:
err = nfserrno(host_err);
goto out;
}
/*
* Create a hardlink
* N.B. After this call _both_ ffhp and tfhp need an fh_put
*/
__be32
nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
char *name, int len, struct svc_fh *tfhp)
{
struct dentry *ddir, *dnew, *dold;
struct inode *dirp;
__be32 err;
int host_err;
err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
if (err)
goto out;
err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
if (err)
goto out;
err = nfserr_isdir;
if (S_ISDIR(tfhp->fh_dentry->d_inode->i_mode))
goto out;
err = nfserr_perm;
if (!len)
goto out;
err = nfserr_exist;
if (isdotent(name, len))
goto out;
host_err = fh_want_write(tfhp);
if (host_err) {
err = nfserrno(host_err);
goto out;
}
fh_lock_nested(ffhp, I_MUTEX_PARENT);
ddir = ffhp->fh_dentry;
dirp = ddir->d_inode;
dnew = lookup_one_len(name, ddir, len);
host_err = PTR_ERR(dnew);
if (IS_ERR(dnew))
goto out_nfserr;
dold = tfhp->fh_dentry;
err = nfserr_noent;
if (!dold->d_inode)
goto out_dput;
host_err = vfs_link(dold, dirp, dnew, NULL);
if (!host_err) {
err = nfserrno(commit_metadata(ffhp));
if (!err)
err = nfserrno(commit_metadata(tfhp));
} else {
if (host_err == -EXDEV && rqstp->rq_vers == 2)
err = nfserr_acces;
else
err = nfserrno(host_err);
}
out_dput:
dput(dnew);
out_unlock:
fh_unlock(ffhp);
fh_drop_write(tfhp);
out:
return err;
out_nfserr:
err = nfserrno(host_err);
goto out_unlock;
}
/*
* Rename a file
* N.B. After this call _both_ ffhp and tfhp need an fh_put
*/
__be32
nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
struct svc_fh *tfhp, char *tname, int tlen)
{
struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap;
struct inode *fdir, *tdir;
__be32 err;
int host_err;
err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
if (err)
goto out;
err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
if (err)
goto out;
fdentry = ffhp->fh_dentry;
fdir = fdentry->d_inode;
tdentry = tfhp->fh_dentry;
tdir = tdentry->d_inode;
err = nfserr_perm;
if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
goto out;
host_err = fh_want_write(ffhp);
if (host_err) {
err = nfserrno(host_err);
goto out;
}
/* cannot use fh_lock as we need deadlock protective ordering
* so do it by hand */
trap = lock_rename(tdentry, fdentry);
ffhp->fh_locked = tfhp->fh_locked = 1;
fill_pre_wcc(ffhp);
fill_pre_wcc(tfhp);
odentry = lookup_one_len(fname, fdentry, flen);
host_err = PTR_ERR(odentry);
if (IS_ERR(odentry))
goto out_nfserr;
host_err = -ENOENT;
if (!odentry->d_inode)
goto out_dput_old;
host_err = -EINVAL;
if (odentry == trap)
goto out_dput_old;
ndentry = lookup_one_len(tname, tdentry, tlen);
host_err = PTR_ERR(ndentry);
if (IS_ERR(ndentry))
goto out_dput_old;
host_err = -ENOTEMPTY;
if (ndentry == trap)
goto out_dput_new;
host_err = -EXDEV;
if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
goto out_dput_new;
if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
goto out_dput_new;
host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL);
if (!host_err) {
host_err = commit_metadata(tfhp);
if (!host_err)
host_err = commit_metadata(ffhp);
}
out_dput_new:
dput(ndentry);
out_dput_old:
dput(odentry);
out_nfserr:
err = nfserrno(host_err);
/* we cannot reply on fh_unlock on the two filehandles,
* as that would do the wrong thing if the two directories
* were the same, so again we do it by hand
*/
fill_post_wcc(ffhp);
fill_post_wcc(tfhp);
unlock_rename(tdentry, fdentry);
ffhp->fh_locked = tfhp->fh_locked = 0;
fh_drop_write(ffhp);
out:
return err;
}
/*
* Unlink a file or directory
* N.B. After this call fhp needs an fh_put
*/
__be32
nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
char *fname, int flen)
{
struct dentry *dentry, *rdentry;
struct inode *dirp;
__be32 err;
int host_err;
err = nfserr_acces;
if (!flen || isdotent(fname, flen))
goto out;
err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
if (err)
goto out;
host_err = fh_want_write(fhp);
if (host_err)
goto out_nfserr;
fh_lock_nested(fhp, I_MUTEX_PARENT);
dentry = fhp->fh_dentry;
dirp = dentry->d_inode;
rdentry = lookup_one_len(fname, dentry, flen);
host_err = PTR_ERR(rdentry);
if (IS_ERR(rdentry))
goto out_nfserr;
if (!rdentry->d_inode) {
dput(rdentry);
err = nfserr_noent;
goto out;
}
if (!type)
type = rdentry->d_inode->i_mode & S_IFMT;
if (type != S_IFDIR)
host_err = vfs_unlink(dirp, rdentry, NULL);
else
host_err = vfs_rmdir(dirp, rdentry);
if (!host_err)
host_err = commit_metadata(fhp);
dput(rdentry);
out_nfserr:
err = nfserrno(host_err);
out:
return err;
}
/*
* We do this buffering because we must not call back into the file
* system's ->lookup() method from the filldir callback. That may well
* deadlock a number of file systems.
*
* This is based heavily on the implementation of same in XFS.
*/
struct buffered_dirent {
u64 ino;
loff_t offset;
int namlen;
unsigned int d_type;
char name[];
};
struct readdir_data {
struct dir_context ctx;
char *dirent;
size_t used;
int full;
};
static int nfsd_buffered_filldir(void *__buf, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct readdir_data *buf = __buf;
struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
unsigned int reclen;
reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
if (buf->used + reclen > PAGE_SIZE) {
buf->full = 1;
return -EINVAL;
}
de->namlen = namlen;
de->offset = offset;
de->ino = ino;
de->d_type = d_type;
memcpy(de->name, name, namlen);
buf->used += reclen;
return 0;
}
static __be32 nfsd_buffered_readdir(struct file *file, filldir_t func,
struct readdir_cd *cdp, loff_t *offsetp)
{
struct buffered_dirent *de;
int host_err;
int size;
loff_t offset;
struct readdir_data buf = {
.ctx.actor = nfsd_buffered_filldir,
.dirent = (void *)__get_free_page(GFP_KERNEL)
};
if (!buf.dirent)
return nfserrno(-ENOMEM);
offset = *offsetp;
while (1) {
struct inode *dir_inode = file_inode(file);
unsigned int reclen;
cdp->err = nfserr_eof; /* will be cleared on successful read */
buf.used = 0;
buf.full = 0;
host_err = iterate_dir(file, &buf.ctx);
if (buf.full)
host_err = 0;
if (host_err < 0)
break;
size = buf.used;
if (!size)
break;
/*
* Various filldir functions may end up calling back into
* lookup_one_len() and the file system's ->lookup() method.
* These expect i_mutex to be held, as it would within readdir.
*/
host_err = mutex_lock_killable(&dir_inode->i_mutex);
if (host_err)
break;
de = (struct buffered_dirent *)buf.dirent;
while (size > 0) {
offset = de->offset;
if (func(cdp, de->name, de->namlen, de->offset,
de->ino, de->d_type))
break;
if (cdp->err != nfs_ok)
break;
reclen = ALIGN(sizeof(*de) + de->namlen,
sizeof(u64));
size -= reclen;
de = (struct buffered_dirent *)((char *)de + reclen);
}
mutex_unlock(&dir_inode->i_mutex);
if (size > 0) /* We bailed out early */
break;
offset = vfs_llseek(file, 0, SEEK_CUR);
}
free_page((unsigned long)(buf.dirent));
if (host_err)
return nfserrno(host_err);
*offsetp = offset;
return cdp->err;
}
/*
* Read entries from a directory.
* The NFSv3/4 verifier we ignore for now.
*/
__be32
nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
struct readdir_cd *cdp, filldir_t func)
{
__be32 err;
struct file *file;
loff_t offset = *offsetp;
int may_flags = NFSD_MAY_READ;
/* NFSv2 only supports 32 bit cookies */
if (rqstp->rq_vers > 2)
may_flags |= NFSD_MAY_64BIT_COOKIE;
err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
if (err)
goto out;
offset = vfs_llseek(file, offset, SEEK_SET);
if (offset < 0) {
err = nfserrno((int)offset);
goto out_close;
}
err = nfsd_buffered_readdir(file, func, cdp, offsetp);
if (err == nfserr_eof || err == nfserr_toosmall)
err = nfs_ok; /* can still be found in ->err */
out_close:
nfsd_close(file);
out:
return err;
}
/*
* Get file system stats
* N.B. After this call fhp needs an fh_put
*/
__be32
nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
{
__be32 err;
err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
if (!err) {
struct path path = {
.mnt = fhp->fh_export->ex_path.mnt,
.dentry = fhp->fh_dentry,
};
if (vfs_statfs(&path, stat))
err = nfserr_io;
}
return err;
}
static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
{
return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
}
/*
* Check for a user's access permissions to this inode.
*/
__be32
nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
struct dentry *dentry, int acc)
{
struct inode *inode = dentry->d_inode;
int err;
if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
return 0;
#if 0
dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
acc,
(acc & NFSD_MAY_READ)? " read" : "",
(acc & NFSD_MAY_WRITE)? " write" : "",
(acc & NFSD_MAY_EXEC)? " exec" : "",
(acc & NFSD_MAY_SATTR)? " sattr" : "",
(acc & NFSD_MAY_TRUNC)? " trunc" : "",
(acc & NFSD_MAY_LOCK)? " lock" : "",
(acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
inode->i_mode,
IS_IMMUTABLE(inode)? " immut" : "",
IS_APPEND(inode)? " append" : "",
__mnt_is_readonly(exp->ex_path.mnt)? " ro" : "");
dprintk(" owner %d/%d user %d/%d\n",
inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
#endif
/* Normally we reject any write/sattr etc access on a read-only file
* system. But if it is IRIX doing check on write-access for a
* device special file, we ignore rofs.
*/
if (!(acc & NFSD_MAY_LOCAL_ACCESS))
if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
if (exp_rdonly(rqstp, exp) ||
__mnt_is_readonly(exp->ex_path.mnt))
return nfserr_rofs;
if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
return nfserr_perm;
}
if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
return nfserr_perm;
if (acc & NFSD_MAY_LOCK) {
/* If we cannot rely on authentication in NLM requests,
* just allow locks, otherwise require read permission, or
* ownership
*/
if (exp->ex_flags & NFSEXP_NOAUTHNLM)
return 0;
else
acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
}
/*
* The file owner always gets access permission for accesses that
* would normally be checked at open time. This is to make
* file access work even when the client has done a fchmod(fd, 0).
*
* However, `cp foo bar' should fail nevertheless when bar is
* readonly. A sensible way to do this might be to reject all
* attempts to truncate a read-only file, because a creat() call
* always implies file truncation.
* ... but this isn't really fair. A process may reasonably call
* ftruncate on an open file descriptor on a file with perm 000.
* We must trust the client to do permission checking - using "ACCESS"
* with NFSv3.
*/
if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
uid_eq(inode->i_uid, current_fsuid()))
return 0;
/* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC));
/* Allow read access to binaries even when mode 111 */
if (err == -EACCES && S_ISREG(inode->i_mode) &&
(acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
err = inode_permission(inode, MAY_EXEC);
return err? nfserrno(err) : 0;
}
void
nfsd_racache_shutdown(void)
{
struct raparms *raparm, *last_raparm;
unsigned int i;
dprintk("nfsd: freeing readahead buffers.\n");
for (i = 0; i < RAPARM_HASH_SIZE; i++) {
raparm = raparm_hash[i].pb_head;
while(raparm) {
last_raparm = raparm;
raparm = raparm->p_next;
kfree(last_raparm);
}
raparm_hash[i].pb_head = NULL;
}
}
/*
* Initialize readahead param cache
*/
int
nfsd_racache_init(int cache_size)
{
int i;
int j = 0;
int nperbucket;
struct raparms **raparm = NULL;
if (raparm_hash[0].pb_head)
return 0;
nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE);
if (nperbucket < 2)
nperbucket = 2;
cache_size = nperbucket * RAPARM_HASH_SIZE;
dprintk("nfsd: allocating %d readahead buffers.\n", cache_size);
for (i = 0; i < RAPARM_HASH_SIZE; i++) {
spin_lock_init(&raparm_hash[i].pb_lock);
raparm = &raparm_hash[i].pb_head;
for (j = 0; j < nperbucket; j++) {
*raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL);
if (!*raparm)
goto out_nomem;
raparm = &(*raparm)->p_next;
}
*raparm = NULL;
}
nfsdstats.ra_size = cache_size;
return 0;
out_nomem:
dprintk("nfsd: kmalloc failed, freeing readahead buffers\n");
nfsd_racache_shutdown();
return -ENOMEM;
}
#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
struct posix_acl *
nfsd_get_posix_acl(struct svc_fh *fhp, int type)
{
struct inode *inode = fhp->fh_dentry->d_inode;
char *name;
void *value = NULL;
ssize_t size;
struct posix_acl *acl;
if (!IS_POSIXACL(inode))
return ERR_PTR(-EOPNOTSUPP);
switch (type) {
case ACL_TYPE_ACCESS:
name = POSIX_ACL_XATTR_ACCESS;
break;
case ACL_TYPE_DEFAULT:
name = POSIX_ACL_XATTR_DEFAULT;
break;
default:
return ERR_PTR(-EOPNOTSUPP);
}
size = nfsd_getxattr(fhp->fh_dentry, name, &value);
if (size < 0)
return ERR_PTR(size);
acl = posix_acl_from_xattr(&init_user_ns, value, size);
kfree(value);
return acl;
}
int
nfsd_set_posix_acl(struct svc_fh *fhp, int type, struct posix_acl *acl)
{
struct inode *inode = fhp->fh_dentry->d_inode;
char *name;
void *value = NULL;
size_t size;
int error;
if (!IS_POSIXACL(inode) ||
!inode->i_op->setxattr || !inode->i_op->removexattr)
return -EOPNOTSUPP;
switch(type) {
case ACL_TYPE_ACCESS:
name = POSIX_ACL_XATTR_ACCESS;
break;
case ACL_TYPE_DEFAULT:
name = POSIX_ACL_XATTR_DEFAULT;
break;
default:
return -EOPNOTSUPP;
}
if (acl && acl->a_count) {
size = posix_acl_xattr_size(acl->a_count);
value = kmalloc(size, GFP_KERNEL);
if (!value)
return -ENOMEM;
error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
if (error < 0)
goto getout;
size = error;
} else
size = 0;
error = fh_want_write(fhp);
if (error)
goto getout;
if (size)
error = vfs_setxattr(fhp->fh_dentry, name, value, size, 0);
else {
if (!S_ISDIR(inode->i_mode) && type == ACL_TYPE_DEFAULT)
error = 0;
else {
error = vfs_removexattr(fhp->fh_dentry, name);
if (error == -ENODATA)
error = 0;
}
}
fh_drop_write(fhp);
getout:
kfree(value);
return error;
}
#endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
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