/*
* 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 vfsmount *mnt = mntget(exp->ex_path.mnt);
struct dentry *mounts = dget(dentry);
int err = 0;
while (follow_down(&mnt,&mounts)&&d_mountpoint(mounts));
exp2 = rqst_exp_get_by_name(rqstp, mnt, mounts);
if (IS_ERR(exp2)) {
if (PTR_ERR(exp2) != -ENOENT)
err = PTR_ERR(exp2);
dput(mounts);
mntput(mnt);
goto out;
}
if ((exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
/* successfully crossed mount point */
exp_put(exp);
*expp = exp2;
dput(dentry);
*dpp = mounts;
} else {
exp_put(exp2);
dput(mounts);
}
mntput(mnt);
out:
return err;
}
static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd,
struct list_head *mntlist)
{
/* stolen from afs code */
int err;
mntget(newmnt);
err = do_add_mount(newmnt, &nd->path, nd->path.mnt->mnt_flags | MNT_SHRINKABLE, mntlist);
switch (err) {
case 0:
path_put(&nd->path);
nd->path.mnt = newmnt;
nd->path.dentry = dget(newmnt->mnt_root);
schedule_delayed_work(&cifs_dfs_automount_task,
cifs_dfs_mountpoint_expiry_timeout);
break;
case -EBUSY:
/* someone else made a mount here whilst we were busy */
while (d_mountpoint(nd->path.dentry) &&
follow_down(&nd->path))
;
err = 0;
default:
mntput(newmnt);
break;
}
return err;
}
/*
* nfs_follow_mountpoint - handle crossing a mountpoint on the server
* @dentry - dentry of mountpoint
* @nd - nameidata info
*
* When we encounter a mountpoint on the server, we want to set up
* a mountpoint on the client too, to prevent inode numbers from
* colliding, and to allow "df" to work properly.
* On NFSv4, we also want to allow for the fact that different
* filesystems may be migrated to different servers in a failover
* situation, and that different filesystems may want to use
* different security flavours.
*/
static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
{
struct vfsmount *mnt;
struct nfs_server *server = NFS_SERVER(dentry->d_inode);
struct dentry *parent;
struct nfs_fh fh;
struct nfs_fattr fattr;
int err;
dprintk("--> nfs_follow_mountpoint()\n");
BUG_ON(IS_ROOT(dentry));
dprintk("%s: enter\n", __FUNCTION__);
dput(nd->dentry);
nd->dentry = dget(dentry);
/* Look it up again */
parent = dget_parent(nd->dentry);
err = server->nfs_client->rpc_ops->lookup(parent->d_inode,
&nd->dentry->d_name,
&fh, &fattr);
dput(parent);
if (err != 0)
goto out_err;
if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL)
mnt = nfs_do_refmount(nd->mnt, nd->dentry);
else
mnt = nfs_do_submount(nd->mnt, nd->dentry, &fh, &fattr);
err = PTR_ERR(mnt);
if (IS_ERR(mnt))
goto out_err;
mntget(mnt);
err = do_add_mount(mnt, nd, nd->mnt->mnt_flags|MNT_SHRINKABLE, &nfs_automount_list);
if (err < 0) {
mntput(mnt);
if (err == -EBUSY)
goto out_follow;
goto out_err;
}
mntput(nd->mnt);
dput(nd->dentry);
nd->mnt = mnt;
nd->dentry = dget(mnt->mnt_root);
schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
out:
dprintk("%s: done, returned %d\n", __FUNCTION__, err);
dprintk("<-- nfs_follow_mountpoint() = %d\n", err);
return ERR_PTR(err);
out_err:
path_release(nd);
goto out;
out_follow:
while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
;
err = 0;
goto out;
}
/*
* Walk down the mount stack looking for an autofs mount that
* has the requested mount type (ie. indirect, direct or offset).
*/
static int autofs_dev_ioctl_find_sbi_type(struct nameidata *nd, unsigned int type)
{
struct dentry *dentry;
struct autofs_info *ino;
unsigned int err;
err = -ENOENT;
/* Lookup the dentry name at the base of our mount point */
dentry = d_lookup(nd->path.dentry, &nd->last);
if (!dentry)
goto out;
dput(nd->path.dentry);
nd->path.dentry = dentry;
/* And follow the mount stack looking for our autofs mount */
while (follow_down(&nd->path.mnt, &nd->path.dentry)) {
ino = autofs4_dentry_ino(nd->path.dentry);
if (ino && ino->sbi->type & type) {
err = 0;
break;
}
}
out:
return err;
}
/*
* Check if the given path is a mountpoint.
*
* If we are supplied with the file descriptor of an autofs
* mount we're looking for a specific mount. In this case
* the path is considered a mountpoint if it is itself a
* mountpoint or contains a mount, such as a multi-mount
* without a root mount. In this case we return 1 if the
* path is a mount point and the super magic of the covering
* mount if there is one or 0 if it isn't a mountpoint.
*
* If we aren't supplied with a file descriptor then we
* lookup the nameidata of the path and check if it is the
* root of a mount. If a type is given we are looking for
* a particular autofs mount and if we don't find a match
* we return fail. If the located nameidata path is the
* root of a mount we return 1 along with the super magic
* of the mount or 0 otherwise.
*
* In both cases the the device number (as returned by
* new_encode_dev()) is also returned.
*/
static int autofs_dev_ioctl_ismountpoint(struct file *fp,
struct autofs_sb_info *sbi,
struct autofs_dev_ioctl *param)
{
struct path path;
const char *name;
unsigned int type;
unsigned int devid, magic;
int err = -ENOENT;
if (param->size <= sizeof(*param)) {
err = -EINVAL;
goto out;
}
name = param->path;
type = param->ismountpoint.in.type;
param->ismountpoint.out.devid = devid = 0;
param->ismountpoint.out.magic = magic = 0;
if (!fp || param->ioctlfd == -1) {
if (autofs_type_any(type))
err = kern_path(name, LOOKUP_FOLLOW, &path);
else
err = find_autofs_mount(name, &path, test_by_type, &type);
if (err)
goto out;
devid = new_encode_dev(path.mnt->mnt_sb->s_dev);
err = 0;
if (path.dentry->d_inode &&
path.mnt->mnt_root == path.dentry) {
err = 1;
magic = path.dentry->d_inode->i_sb->s_magic;
}
} else {
dev_t dev = sbi->sb->s_dev;
err = find_autofs_mount(name, &path, test_by_dev, &dev);
if (err)
goto out;
devid = new_encode_dev(dev);
err = have_submounts(path.dentry);
if (path.mnt->mnt_mountpoint != path.mnt->mnt_root) {
if (follow_down(&path))
magic = path.mnt->mnt_sb->s_magic;
}
}
param->ismountpoint.out.devid = devid;
param->ismountpoint.out.magic = magic;
path_put(&path);
out:
return err;
}
static int autofs4_dir_open(struct inode *inode, struct file *file)
{
struct dentry *dentry = file->f_dentry;
struct vfsmount *mnt = file->f_vfsmnt;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
int status;
DPRINTK("file=%p dentry=%p %.*s",
file, dentry, dentry->d_name.len, dentry->d_name.name);
if (autofs4_oz_mode(sbi))
goto out;
if (autofs4_ispending(dentry)) {
DPRINTK("dentry busy");
return -EBUSY;
}
if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
struct nameidata nd;
int empty;
/* In case there are stale directory dentrys from a failed mount */
spin_lock(&dcache_lock);
empty = list_empty(&dentry->d_subdirs);
spin_unlock(&dcache_lock);
if (!empty)
d_invalidate(dentry);
nd.flags = LOOKUP_DIRECTORY;
status = (dentry->d_op->d_revalidate)(dentry, &nd);
if (!status)
return -ENOENT;
}
if (d_mountpoint(dentry)) {
struct file *fp = NULL;
struct vfsmount *fp_mnt = mntget(mnt);
struct dentry *fp_dentry = dget(dentry);
while (follow_down(&fp_mnt, &fp_dentry) && d_mountpoint(fp_dentry));
fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);
status = PTR_ERR(fp);
if (IS_ERR(fp)) {
file->private_data = NULL;
return status;
}
file->private_data = fp;
}
out:
return 0;
}
void get_physical_root(struct path *root)
{
struct krg_namespace *krg_ns = find_get_krg_ns();
BUG_ON(!krg_ns);
root->mnt = krg_ns->root_nsproxy.mnt_ns->root;
root->dentry = root->mnt->mnt_root;
path_get(root);
put_krg_ns(krg_ns);
while (d_mountpoint(root->dentry) &&
follow_down(&root->mnt, &root->dentry))
;
}
/*
* follow a link from a mountpoint directory, thus causing it to be mounted
*/
static void *afs_mntpt_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct vfsmount *newmnt;
int err;
_enter("%p{%s},{%s:%p{%s},}",
dentry,
dentry->d_name.name,
nd->mnt->mnt_devname,
dentry,
nd->dentry->d_name.name);
dput(nd->dentry);
nd->dentry = dget(dentry);
newmnt = afs_mntpt_do_automount(nd->dentry);
if (IS_ERR(newmnt)) {
path_release(nd);
return (void *)newmnt;
}
mntget(newmnt);
err = do_add_mount(newmnt, nd, MNT_SHRINKABLE, &afs_vfsmounts);
switch (err) {
case 0:
mntput(nd->mnt);
dput(nd->dentry);
nd->mnt = newmnt;
nd->dentry = dget(newmnt->mnt_root);
schedule_delayed_work(&afs_mntpt_expiry_timer,
afs_mntpt_expiry_timeout * HZ);
break;
case -EBUSY:
/* someone else made a mount here whilst we were busy */
while (d_mountpoint(nd->dentry) &&
follow_down(&nd->mnt, &nd->dentry))
;
err = 0;
default:
mntput(newmnt);
break;
}
_leave(" = %d", err);
return ERR_PTR(err);
}
/* Check a mount point for busyness */
static int autofs4_mount_busy(struct vfsmount *mnt, struct dentry *dentry)
{
struct dentry *top = dentry;
int status = 1;
DPRINTK("dentry %p %.*s",
dentry, (int)dentry->d_name.len, dentry->d_name.name);
mntget(mnt);
dget(dentry);
if (!follow_down(&mnt, &dentry))
goto done;
if (is_autofs4_dentry(dentry)) {
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
/* This is an autofs submount, we can't expire it */
if (autofs_type_indirect(sbi->type))
goto done;
/*
* Otherwise it's an offset mount and we need to check
* if we can umount its mount, if there is one.
*/
if (!d_mountpoint(dentry))
goto done;
}
/* Update the expiry counter if fs is busy */
if (!may_umount_tree(mnt)) {
struct autofs_info *ino = autofs4_dentry_ino(top);
ino->last_used = jiffies;
goto done;
}
status = 0;
done:
DPRINTK("returning = %d", status);
dput(dentry);
mntput(mnt);
return status;
}
/*
* Walk down the mount stack looking for an autofs mount that
* has the requested device number (aka. new_encode_dev(sb->s_dev).
*/
static int autofs_dev_ioctl_find_super(struct nameidata *nd, dev_t devno)
{
struct dentry *dentry;
struct inode *inode;
struct super_block *sb;
dev_t s_dev;
unsigned int err;
err = -ENOENT;
/* Lookup the dentry name at the base of our mount point */
dentry = d_lookup(nd->path.dentry, &nd->last);
if (!dentry)
goto out;
dput(nd->path.dentry);
nd->path.dentry = dentry;
/* And follow the mount stack looking for our autofs mount */
while (follow_down(&nd->path.mnt, &nd->path.dentry)) {
inode = nd->path.dentry->d_inode;
if (!inode)
break;
sb = inode->i_sb;
s_dev = new_encode_dev(sb->s_dev);
if (devno == s_dev) {
if (sb->s_magic == AUTOFS_SUPER_MAGIC) {
err = 0;
break;
}
}
}
out:
return 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;
}
/*
* Check if the given path is a mountpoint.
*
* If we are supplied with the file descriptor of an autofs
* mount we're looking for a specific mount. In this case
* the path is considered a mountpoint if it is itself a
* mountpoint or contains a mount, such as a multi-mount
* without a root mount. In this case we return 1 if the
* path is a mount point and the super magic of the covering
* mount if there is one or 0 if it isn't a mountpoint.
*
* If we aren't supplied with a file descriptor then we
* lookup the nameidata of the path and check if it is the
* root of a mount. If a type is given we are looking for
* a particular autofs mount and if we don't find a match
* we return fail. If the located nameidata path is the
* root of a mount we return 1 along with the super magic
* of the mount or 0 otherwise.
*
* In both cases the the device number (as returned by
* new_encode_dev()) is also returned.
*/
static int autofs_dev_ioctl_ismountpoint(struct file *fp,
struct autofs_sb_info *sbi,
struct autofs_dev_ioctl *param)
{
struct nameidata nd;
const char *path;
unsigned int type;
int err = -ENOENT;
if (param->size <= sizeof(*param)) {
err = -EINVAL;
goto out;
}
path = param->path;
type = param->arg1;
param->arg1 = 0;
param->arg2 = 0;
if (!fp || param->ioctlfd == -1) {
if (type == AUTOFS_TYPE_ANY) {
struct super_block *sb;
err = path_lookup(path, LOOKUP_FOLLOW, &nd);
if (err)
goto out;
sb = nd.path.dentry->d_sb;
param->arg1 = new_encode_dev(sb->s_dev);
} else {
struct autofs_info *ino;
err = path_lookup(path, LOOKUP_PARENT, &nd);
if (err)
goto out;
err = autofs_dev_ioctl_find_sbi_type(&nd, type);
if (err)
goto out_release;
ino = autofs4_dentry_ino(nd.path.dentry);
param->arg1 = autofs4_get_dev(ino->sbi);
}
err = 0;
if (nd.path.dentry->d_inode &&
nd.path.mnt->mnt_root == nd.path.dentry) {
err = 1;
param->arg2 = nd.path.dentry->d_inode->i_sb->s_magic;
}
} else {
dev_t devid = new_encode_dev(sbi->sb->s_dev);
err = path_lookup(path, LOOKUP_PARENT, &nd);
if (err)
goto out;
err = autofs_dev_ioctl_find_super(&nd, devid);
if (err)
goto out_release;
param->arg1 = autofs4_get_dev(sbi);
err = have_submounts(nd.path.dentry);
if (nd.path.mnt->mnt_mountpoint != nd.path.mnt->mnt_root) {
if (follow_down(&nd.path.mnt, &nd.path.dentry)) {
struct inode *inode = nd.path.dentry->d_inode;
param->arg2 = inode->i_sb->s_magic;
}
}
}
out_release:
path_put(&nd.path);
out:
return err;
}
static void *cifs_dfs_follow_mountpoint(struct dentry *dentry,
struct nameidata *nd)
{
DFS_INFO3_PARAM *referrals = NULL;
unsigned int num_referrals = 0;
struct cifs_sb_info *cifs_sb;
struct cifsSesInfo *ses;
char *full_path = NULL;
int xid, i;
int rc = 0;
struct vfsmount *mnt = ERR_PTR(-ENOENT);
cFYI(1, ("in %s", __FUNCTION__ ));
BUG_ON(IS_ROOT(dentry));
xid = GetXid();
dput(nd->dentry);
nd->dentry = dget(dentry);
if (d_mountpoint(nd->dentry)) {
goto out_follow;
}
if ( dentry->d_inode == NULL ) {
rc = -EINVAL;
goto out_err;
}
cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
ses = cifs_sb->tcon->ses;
if ( !ses ) {
rc = -EINVAL;
goto out_err;
}
full_path = build_full_dfs_path_from_dentry(dentry);
if ( full_path == NULL ) {
rc = -ENOMEM;
goto out_err;
}
rc = get_dfs_path(xid, ses , full_path, cifs_sb->local_nls,
&num_referrals, &referrals,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
for (i = 0; i < num_referrals; i++) {
cFYI(1, ("%s: ref path: %s", __FUNCTION__,
referrals[i].path_name));
cFYI(1, ("%s: node path: %s", __FUNCTION__,
referrals[i].node_name ));
cFYI(1, ("%s: fl: %hd, serv_type: %hd, ref_flags: %hd, "
"path_consumed: %hd", __FUNCTION__,
referrals[i].flags, referrals[i].server_type,
referrals[i].ref_flag, referrals[i].PathConsumed));
/* connect to storage node */
if (referrals[i].flags & DFSREF_STORAGE_SERVER) {
int len;
len = strlen(referrals[i].node_name);
if (len < 2) {
cERROR(1, ("%s: Net Address path too short: %s",
__FUNCTION__, referrals[i].node_name ));
rc = -EINVAL;
goto out_err;
} else {
mnt = cifs_dfs_do_refmount(nd->mnt,
nd->dentry,
referrals[i].node_name);
cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p",
__FUNCTION__,
referrals[i].node_name, mnt));
if ( !rc ) {
/* have server so stop here & return */
break;
}
}
}
}
rc = PTR_ERR(mnt);
if (IS_ERR(mnt))
goto out_err;
mntget(mnt);
rc = do_add_mount(mnt, nd, nd->mnt->mnt_flags,
&cifs_dfs_automount_list);
if (rc < 0) {
mntput(mnt);
if (rc == -EBUSY)
goto out_follow;
goto out_err;
}
mntput(nd->mnt);
dput(nd->dentry);
nd->mnt = mnt;
nd->dentry = dget(mnt->mnt_root);
out:
FreeXid(xid);
free_dfs_info_array(referrals, num_referrals);
cFYI(1, ("leaving %s", __FUNCTION__ ));
return ERR_PTR(rc);
out_err:
if ( full_path ) kfree(full_path);
path_release(nd);
goto out;
out_follow:
while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
;
rc = 0;
goto out;
}
static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
{
struct vfsmount *mnt;
struct nfs_server *server = NFS_SERVER(dentry->d_inode);
struct dentry *parent;
struct nfs_fh *fh = NULL;
struct nfs_fattr *fattr = NULL;
int err;
dprintk("--> nfs_follow_mountpoint()\n");
err = -ESTALE;
if (IS_ROOT(dentry))
goto out_err;
err = -ENOMEM;
fh = nfs_alloc_fhandle();
fattr = nfs_alloc_fattr();
if (fh == NULL || fattr == NULL)
goto out_err;
dprintk("%s: enter\n", __func__);
dput(nd->path.dentry);
nd->path.dentry = dget(dentry);
/* Look it up again */
parent = dget_parent(nd->path.dentry);
err = server->nfs_client->rpc_ops->lookup(parent->d_inode,
&nd->path.dentry->d_name,
fh, fattr);
dput(parent);
if (err != 0)
goto out_err;
if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
mnt = nfs_do_refmount(nd->path.mnt, nd->path.dentry);
else
mnt = nfs_do_submount(nd->path.mnt, nd->path.dentry, fh,
fattr);
err = PTR_ERR(mnt);
if (IS_ERR(mnt))
goto out_err;
mntget(mnt);
err = do_add_mount(mnt, &nd->path, nd->path.mnt->mnt_flags|MNT_SHRINKABLE,
&nfs_automount_list);
if (err < 0) {
mntput(mnt);
if (err == -EBUSY)
goto out_follow;
goto out_err;
}
path_put(&nd->path);
nd->path.mnt = mnt;
nd->path.dentry = dget(mnt->mnt_root);
schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
out:
nfs_free_fattr(fattr);
nfs_free_fhandle(fh);
dprintk("%s: done, returned %d\n", __func__, err);
dprintk("<-- nfs_follow_mountpoint() = %d\n", err);
return ERR_PTR(err);
out_err:
path_put(&nd->path);
goto out;
out_follow:
while (d_mountpoint(nd->path.dentry) &&
follow_down(&nd->path))
;
err = 0;
goto out;
}
static void*
snap_mountpoint_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct vfsmount *mnt = ERR_PTR(-ENOENT);
vnode_t *dir_vp = NULL;
char *snapname = NULL;
char *zfs_fs_name = NULL;
int rc = 0;
vfs_t *vfsp = NULL;
ASSERT(dentry->d_parent);
dir_vp = LZFS_ITOV(dentry->d_parent->d_inode);
vfsp = dir_vp->v_vfsp;
ASSERT(vfsp);
zfs_fs_name = kzalloc(MAXNAMELEN, KM_SLEEP);
dput(nd->path.dentry);
nd->path.dentry = dget(dentry);
zfs_fs_name_fn(vfsp->vfs_data, zfs_fs_name);
snapname = kzalloc(strlen(zfs_fs_name) +
strlen(dentry->d_name.name) + 2, KM_SLEEP);
snapname = strncpy(snapname, zfs_fs_name, strlen(zfs_fs_name) + 1);
snapname = strcat(snapname, "@");
snapname = strcat(snapname, dentry->d_name.name);
mnt = vfs_kern_mount(&lzfs_fs_type, 0, snapname, NULL);
((vfs_t *)mnt->mnt_sb->s_fs_info)->vfs_mntpt = dentry;
mntget(mnt);
rc = PTR_ERR(mnt);
if (IS_ERR(mnt)) {
goto out_err;
}
mnt->mnt_mountpoint = dentry;
ASSERT(nd);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
rc = do_add_mount(mnt, nd,
nd->path.mnt->mnt_flags | MNT_READONLY, NULL);
#else
rc = do_add_mount(mnt, &nd->path,
nd->path.mnt->mnt_flags | MNT_READONLY, NULL);
#endif
switch (rc) {
case 0:
path_put(&nd->path);
nd->path.mnt = mnt;
nd->path.dentry = dget(mnt->mnt_root);
break;
case -EBUSY:
nd->path.dentry = dget(mnt->mnt_root);
/* someone else made a mount here whilst we were busy */
#ifdef HAVE_2ARGS_FOLLOW_DOWN /* for kernel version < 2.6.31 */
while (d_mountpoint(nd->path.dentry) &&
follow_down(&mnt, &nd->path.dentry)) {
;
}
#else
while (d_mountpoint(nd->path.dentry) &&
follow_down(&nd->path)) {
;
}
#endif
rc = 0;
default:
mntput(mnt);
break;
}
kfree(zfs_fs_name);
kfree(snapname);
return ERR_PTR(rc);
out_err:
path_put(&nd->path);
kfree(zfs_fs_name);
kfree(snapname);
return ERR_PTR(rc);
}