static int find_autofs_mount(const char *pathname,
struct path *res,
int test(struct path *path, void *data),
void *data)
{
struct path path;
int err = kern_path(pathname, 0, &path);
if (err)
return err;
err = -ENOENT;
while (path.dentry == path.mnt->mnt_root) {
if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
if (test(&path, data)) {
path_get(&path);
if (!err) /* already found some */
path_put(res);
*res = path;
err = 0;
}
}
if (!follow_up(&path))
break;
}
path_put(&path);
return err;
}
/*
* Try to find a suitable devpts filesystem. We support the following
* scenarios:
* - The ptmx device node is located in the same directory as the devpts
* mount where the pts device nodes are located.
* This is e.g. the case when calling open on the /dev/pts/ptmx device
* node when the devpts filesystem is mounted at /dev/pts.
* - The ptmx device node is located outside the devpts filesystem mount
* where the pts device nodes are located. For example, the ptmx device
* is a symlink, separate device node, or bind-mount.
* A supported scenario is bind-mounting /dev/pts/ptmx to /dev/ptmx and
* then calling open on /dev/ptmx. In this case a suitable pts
* subdirectory can be found in the common parent directory /dev of the
* devpts mount and the ptmx bind-mount, after resolving the /dev/ptmx
* bind-mount.
* If no suitable pts subdirectory can be found this function will fail.
* This is e.g. the case when bind-mounting /dev/pts/ptmx to /ptmx.
*/
struct vfsmount *devpts_mntget(struct file *filp, struct pts_fs_info *fsi)
{
struct path path;
int err = 0;
path = filp->f_path;
path_get(&path);
/* Walk upward while the start point is a bind mount of
* a single file.
*/
while (path.mnt->mnt_root == path.dentry)
if (follow_up(&path) == 0)
break;
/* devpts_ptmx_path() finds a devpts fs or returns an error. */
if ((path.mnt->mnt_sb->s_magic != DEVPTS_SUPER_MAGIC) ||
(DEVPTS_SB(path.mnt->mnt_sb) != fsi))
err = devpts_ptmx_path(&path);
dput(path.dentry);
if (!err) {
if (DEVPTS_SB(path.mnt->mnt_sb) == fsi)
return path.mnt;
err = -ENODEV;
}
mntput(path.mnt);
return ERR_PTR(err);
}
__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;
__be32 err;
int host_err;
dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
/* Obtain dentry and export. */
err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
if (err)
return err;
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))
dentry = dget(dparent); /* .. == . just like at / */
else {
/* checking mountpoint crossing is very different when stepping up */
struct svc_export *exp2 = NULL;
struct dentry *dp;
struct vfsmount *mnt = mntget(exp->ex_path.mnt);
dentry = dget(dparent);
while(dentry == mnt->mnt_root && follow_up(&mnt, &dentry))
;
dp = dget_parent(dentry);
dput(dentry);
dentry = dp;
exp2 = rqst_exp_parent(rqstp, mnt, dentry);
if (PTR_ERR(exp2) == -ENOENT) {
dput(dentry);
dentry = dget(dparent);
} else if (IS_ERR(exp2)) {
host_err = PTR_ERR(exp2);
dput(dentry);
mntput(mnt);
goto out_nfserr;
} else {
exp_put(exp);
exp = exp2;
}
mntput(mnt);
}
} else {
fh_lock(fhp);
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 (d_mountpoint(dentry)) {
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_CROSSMNT, 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 <*****@*****.**>
*/
int
nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
int len, struct svc_fh *resfh)
{
struct svc_export *exp;
struct dentry *dparent;
struct dentry *dentry;
int err;
dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
/* Obtain dentry and export. */
err = fh_verify(rqstp, fhp, S_IFDIR, MAY_EXEC);
if (err)
goto out;
dparent = fhp->fh_dentry;
exp = fhp->fh_export;
err = nfserr_acces;
/* Lookup the name, but don't follow links */
if (isdotent(name, len)) {
if (len==1)
dentry = dget(dparent);
else { /* must be ".." */
/* checking mountpoint crossing is very different when stepping up */
if (dparent == exp->ex_dentry) {
if (!EX_CROSSMNT(exp))
dentry = dget(dparent); /* .. == . just like at / */
else
{
struct svc_export *exp2 = NULL;
struct dentry *dp;
struct vfsmount *mnt = mntget(exp->ex_mnt);
dentry = dget(dparent);
while(follow_up(&mnt, &dentry))
;
dp = dget(dentry->d_parent);
dput(dentry);
dentry = dp;
for ( ; exp2 == NULL && dp->d_parent != dp;
dp=dp->d_parent)
exp2 = exp_get(exp->ex_client, dp->d_inode->i_dev, dp->d_inode->i_ino);
if (exp2==NULL) {
dput(dentry);
dentry = dget(dparent);
} else {
exp = exp2;
}
mntput(mnt);
}
} else
dentry = dget(dparent->d_parent);
}
} else {
fh_lock(fhp);
dentry = lookup_one_len(name, dparent, len);
err = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_nfserr;
/*
* check if we have crossed a mount point ...
*/
if (d_mountpoint(dentry)) {
struct svc_export *exp2 = NULL;
struct vfsmount *mnt = mntget(exp->ex_mnt);
struct dentry *mounts = dget(dentry);
while (follow_down(&mnt,&mounts)&&d_mountpoint(mounts))
;
exp2 = exp_get(rqstp->rq_client,
mounts->d_inode->i_dev,
mounts->d_inode->i_ino);
if (exp2 && EX_CROSSMNT(exp2)) {
/* successfully crossed mount point */
exp = exp2;
dput(dentry);
dentry = mounts;
} else
dput(mounts);
mntput(mnt);
}
}
/*
* 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:
return err;
out_nfserr:
err = nfserrno(err);
goto out;
}
/*
* 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 <*****@*****.**>
*/
int
nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
int len, struct svc_fh *resfh)
{
struct svc_export *exp;
struct dentry *dparent;
struct dentry *dentry;
int err;
dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
/* Obtain dentry and export. */
err = fh_verify(rqstp, fhp, S_IFDIR, MAY_EXEC);
if (err)
return err;
dparent = fhp->fh_dentry;
exp = fhp->fh_export;
exp_get(exp);
err = nfserr_acces;
/* Lookup the name, but don't follow links */
if (isdotent(name, len)) {
if (len==1)
dentry = dget(dparent);
else if (dparent != exp->ex_dentry) {
dentry = dget_parent(dparent);
} else if (!EX_NOHIDE(exp))
dentry = dget(dparent); /* .. == . just like at / */
else {
/* checking mountpoint crossing is very different when stepping up */
struct svc_export *exp2 = NULL;
struct dentry *dp;
struct vfsmount *mnt = mntget(exp->ex_mnt);
dentry = dget(dparent);
while(dentry == mnt->mnt_root && follow_up(&mnt, &dentry))
;
dp = dget_parent(dentry);
dput(dentry);
dentry = dp;
exp2 = exp_parent(exp->ex_client, mnt, dentry,
&rqstp->rq_chandle);
if (IS_ERR(exp2)) {
err = PTR_ERR(exp2);
dput(dentry);
mntput(mnt);
goto out_nfserr;
}
if (!exp2) {
dput(dentry);
dentry = dget(dparent);
} else {
exp_put(exp);
exp = exp2;
}
mntput(mnt);
}
} else {
fh_lock(fhp);
dentry = lookup_one_len(name, dparent, len);
err = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_nfserr;
/*
* check if we have crossed a mount point ...
*/
if (d_mountpoint(dentry)) {
if ((err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
dput(dentry);
goto out_nfserr;
}
}
}
/*
* 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;
dput(dentry);
out:
exp_put(exp);
return err;
out_nfserr:
err = nfserrno(err);
goto out;
}