static int
au_call_encode_fh(struct dentry *h_dentry, __u32 *fh, int *max_len,
int connectable)
{
/* in linux-2.6.24, it takes struct fid * as file handle */
return exportfs_encode_fh(h_dentry, (void *)fh, max_len, connectable);
}
/*
* Compose a file handle for an NFS reply.
*
* Note that when first composed, the dentry may not yet have
* an inode. In this case a call to fh_update should be made
* before the fh goes out on the wire ...
*/
static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
struct dentry *dentry)
{
if (dentry != exp->ex_path.dentry) {
struct fid *fid = (struct fid *)
(fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
fhp->fh_handle.fh_fileid_type =
exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
fhp->fh_handle.fh_size += maxsize * 4;
} else {
fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
}
}
static long do_sys_name_to_handle(struct path *path,
struct file_handle __user *ufh,
int __user *mnt_id)
{
long retval;
struct file_handle f_handle;
int handle_dwords, handle_bytes;
struct file_handle *handle = NULL;
/*
* We need t make sure wether the file system
* support decoding of the file handle
*/
if (!path->mnt->mnt_sb->s_export_op ||
!path->mnt->mnt_sb->s_export_op->fh_to_dentry)
return -EOPNOTSUPP;
if (copy_from_user(&f_handle, ufh, sizeof(struct file_handle)))
return -EFAULT;
if (f_handle.handle_bytes > MAX_HANDLE_SZ)
return -EINVAL;
handle = kmalloc(sizeof(struct file_handle) + f_handle.handle_bytes,
GFP_KERNEL);
if (!handle)
return -ENOMEM;
/* convert handle size to multiple of sizeof(u32) */
handle_dwords = f_handle.handle_bytes >> 2;
/* we ask for a non connected handle */
retval = exportfs_encode_fh(path->dentry,
(struct fid *)handle->f_handle,
&handle_dwords, 0);
handle->handle_type = retval;
/* convert handle size to bytes */
handle_bytes = handle_dwords * sizeof(u32);
handle->handle_bytes = handle_bytes;
if ((handle->handle_bytes > f_handle.handle_bytes) ||
(retval == 255) || (retval == -ENOSPC)) {
/* As per old exportfs_encode_fh documentation
* we could return ENOSPC to indicate overflow
* But file system returned 255 always. So handle
* both the values
*/
/*
* set the handle size to zero so we copy only
* non variable part of the file_handle
*/
handle_bytes = 0;
retval = -EOVERFLOW;
} else
retval = 0;
/* copy the mount id */
if (copy_to_user(mnt_id, &path->mnt->mnt_id, sizeof(*mnt_id)) ||
copy_to_user(ufh, handle,
sizeof(struct file_handle) + handle_bytes))
retval = -EFAULT;
kfree(handle);
return retval;
}
static struct dentry *
aufs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
int fh_type)
{
struct dentry *dentry;
__u32 *fh = fid->raw;
ino_t ino, dir_ino;
aufs_bindex_t bindex;
struct au_nfsd_si_lock nsi_lock = {
.force_lock = 0
};
dentry = ERR_PTR(-ESTALE);
/* it should never happen, but the file handle is unreliable */
if (unlikely(fh_len < Fh_tail))
goto out;
nsi_lock.sigen = fh[Fh_sigen];
nsi_lock.br_id = fh[Fh_br_id];
/* branch id may be wrapped around */
bindex = si_nfsd_read_lock(sb, &nsi_lock);
if (unlikely(bindex < 0))
goto out;
nsi_lock.force_lock = 1;
/* is this inode still cached? */
ino = decode_ino(fh + Fh_ino);
/* it should never happen */
if (unlikely(ino == AUFS_ROOT_INO))
goto out;
dir_ino = decode_ino(fh + Fh_dir_ino);
dentry = decode_by_ino(sb, ino, dir_ino);
if (IS_ERR(dentry))
goto out_unlock;
if (dentry)
goto accept;
/* is the parent dir cached? */
dentry = decode_by_dir_ino(sb, ino, dir_ino, &nsi_lock);
if (IS_ERR(dentry))
goto out_unlock;
if (dentry)
goto accept;
/* lookup path */
dentry = decode_by_path(sb, bindex, ino, fh, fh_len, &nsi_lock);
if (IS_ERR(dentry))
goto out_unlock;
if (unlikely(!dentry))
/* todo?: make it ESTALE */
goto out_unlock;
accept:
if (dentry->d_inode->i_generation == fh[Fh_igen])
goto out_unlock; /* success */
dput(dentry);
dentry = ERR_PTR(-ESTALE);
out_unlock:
si_read_unlock(sb);
out:
AuTraceErrPtr(dentry);
return dentry;
}
#if 0 /* reserved for future use */
/* support subtreecheck option */
static struct dentry *aufs_fh_to_parent(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
struct dentry *parent;
__u32 *fh = fid->raw;
ino_t dir_ino;
dir_ino = decode_ino(fh + Fh_dir_ino);
parent = decode_by_ino(sb, dir_ino, 0);
if (IS_ERR(parent))
goto out;
if (!parent)
parent = decode_by_path(sb, au_br_index(sb, fh[Fh_br_id]),
dir_ino, fh, fh_len);
out:
AuTraceErrPtr(parent);
return parent;
}
#endif
/* ---------------------------------------------------------------------- */
static int aufs_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len,
int connectable)
{
int err;
aufs_bindex_t bindex, bend;
struct super_block *sb, *h_sb;
struct inode *inode;
struct dentry *parent, *h_parent;
struct au_branch *br;
AuDebugOn(au_test_anon(dentry));
parent = NULL;
err = -ENOSPC;
if (unlikely(*max_len <= Fh_tail)) {
AuWarn1("NFSv2 client (max_len %d)?\n", *max_len);
goto out;
}
err = FILEID_ROOT;
if (IS_ROOT(dentry)) {
AuDebugOn(dentry->d_inode->i_ino != AUFS_ROOT_INO);
goto out;
}
err = -EIO;
h_parent = NULL;
sb = dentry->d_sb;
aufs_read_lock(dentry, AuLock_FLUSH | AuLock_IR);
parent = dget_parent(dentry);
di_read_lock_parent(parent, !AuLock_IR);
inode = dentry->d_inode;
AuDebugOn(!inode);
#ifdef CONFIG_AUFS_DEBUG
if (unlikely(!au_opt_test(au_mntflags(sb), XINO)))
AuWarn1("NFS-exporting requires xino\n");
#endif
bend = au_dbtaildir(parent);
for (bindex = au_dbstart(parent); bindex <= bend; bindex++) {
h_parent = au_h_dptr(parent, bindex);
if (h_parent) {
dget(h_parent);
break;
}
}
if (unlikely(!h_parent))
goto out_unlock;
err = -EPERM;
br = au_sbr(sb, bindex);
h_sb = br->br_mnt->mnt_sb;
if (unlikely(!h_sb->s_export_op)) {
AuErr1("%s branch is not exportable\n", au_sbtype(h_sb));
goto out_dput;
}
fh[Fh_br_id] = br->br_id;
fh[Fh_sigen] = au_sigen(sb);
encode_ino(fh + Fh_ino, inode->i_ino);
encode_ino(fh + Fh_dir_ino, parent->d_inode->i_ino);
fh[Fh_igen] = inode->i_generation;
*max_len -= Fh_tail;
fh[Fh_h_type] = exportfs_encode_fh(h_parent, (void *)(fh + Fh_tail),
max_len,
/*connectable or subtreecheck*/0);
err = fh[Fh_h_type];
*max_len += Fh_tail;
/* todo: macros? */
if (err != 255)
err = 99;
else
AuWarn1("%s encode_fh failed\n", au_sbtype(h_sb));
out_dput:
dput(h_parent);
out_unlock:
di_read_unlock(parent, !AuLock_IR);
dput(parent);
aufs_read_unlock(dentry, AuLock_IR);
out:
if (unlikely(err < 0))
err = 255;
return err;
}
