root/fs/ocfs2/export.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * export.c
 *
 * Functions to facilitate NFS exporting
 *
 * Copyright (C) 2002, 2005 Oracle.  All rights reserved.
 */

#include <linux/fs.h>
#include <linux/types.h>

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "dir.h"
#include "dlmglue.h"
#include "dcache.h"
#include "export.h"
#include "inode.h"

#include "buffer_head_io.h"
#include "suballoc.h"
#include "ocfs2_trace.h"

struct ocfs2_inode_handle
{
        u64 ih_blkno;
        u32 ih_generation;
};

static struct dentry *ocfs2_get_dentry(struct super_block *sb,
                struct ocfs2_inode_handle *handle)
{
        struct inode *inode;
        struct ocfs2_super *osb = OCFS2_SB(sb);
        u64 blkno = handle->ih_blkno;
        int status, set;
        struct dentry *result;

        trace_ocfs2_get_dentry_begin(sb, handle, (unsigned long long)blkno);

        if (blkno == 0) {
                result = ERR_PTR(-ESTALE);
                goto bail;
        }

        inode = ocfs2_ilookup(sb, blkno);
        /*
         * If the inode exists in memory, we only need to check it's
         * generation number
         */
        if (inode)
                goto check_gen;

        /*
         * This will synchronize us against ocfs2_delete_inode() on
         * all nodes
         */
        status = ocfs2_nfs_sync_lock(osb, 1);
        if (status < 0) {
                mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
                goto check_err;
        }

        status = ocfs2_test_inode_bit(osb, blkno, &set);
        if (status < 0) {
                if (status == -EINVAL) {
                        /*
                         * The blkno NFS gave us doesn't even show up
                         * as an inode, we return -ESTALE to be
                         * nice
                         */
                        status = -ESTALE;
                } else if (status != -ESTALE) {
                        mlog(ML_ERROR, "test inode bit failed %d\n", status);
                }
                goto unlock_nfs_sync;
        }

        trace_ocfs2_get_dentry_test_bit(status, set);
        /* If the inode allocator bit is clear, this inode must be stale */
        if (!set) {
                status = -ESTALE;
                goto unlock_nfs_sync;
        }

        inode = ocfs2_iget(osb, blkno, 0, 0);

unlock_nfs_sync:
        ocfs2_nfs_sync_unlock(osb, 1);

check_err:
        if (status < 0) {
                if (status == -ESTALE) {
                        trace_ocfs2_get_dentry_stale((unsigned long long)blkno,
                                                     handle->ih_generation);
                }
                result = ERR_PTR(status);
                goto bail;
        }

        if (IS_ERR(inode)) {
                mlog_errno(PTR_ERR(inode));
                result = ERR_CAST(inode);
                goto bail;
        }

check_gen:
        if (handle->ih_generation != inode->i_generation) {
                trace_ocfs2_get_dentry_generation((unsigned long long)blkno,
                                                  handle->ih_generation,
                                                  inode->i_generation);
                iput(inode);
                result = ERR_PTR(-ESTALE);
                goto bail;
        }

        result = d_obtain_alias(inode);
        if (IS_ERR(result))
                mlog_errno(PTR_ERR(result));

bail:
        trace_ocfs2_get_dentry_end(result);
        return result;
}

static struct dentry *ocfs2_get_parent(struct dentry *child)
{
        int status;
        u64 blkno;
        struct dentry *parent;
        struct inode *dir = d_inode(child);
        int set;

        trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name,
                               (unsigned long long)OCFS2_I(dir)->ip_blkno);

        status = ocfs2_nfs_sync_lock(OCFS2_SB(dir->i_sb), 1);
        if (status < 0) {
                mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
                parent = ERR_PTR(status);
                goto bail;
        }

        status = ocfs2_inode_lock(dir, NULL, 0);
        if (status < 0) {
                if (status != -ENOENT)
                        mlog_errno(status);
                parent = ERR_PTR(status);
                goto unlock_nfs_sync;
        }

        status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
        if (status < 0) {
                parent = ERR_PTR(-ENOENT);
                goto bail_unlock;
        }

        status = ocfs2_test_inode_bit(OCFS2_SB(dir->i_sb), blkno, &set);
        if (status < 0) {
                if (status == -EINVAL) {
                        status = -ESTALE;
                } else if (status != -ESTALE) {
                        mlog(ML_ERROR, "test inode bit failed %d\n", status);
                }
                parent = ERR_PTR(status);
                goto bail_unlock;
        }

        trace_ocfs2_get_dentry_test_bit(status, set);
        if (!set) {
                status = -ESTALE;
                parent = ERR_PTR(status);
                goto bail_unlock;
        }

        parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));

bail_unlock:
        ocfs2_inode_unlock(dir, 0);

unlock_nfs_sync:
        ocfs2_nfs_sync_unlock(OCFS2_SB(dir->i_sb), 1);

bail:
        trace_ocfs2_get_parent_end(parent);

        return parent;
}

static int ocfs2_encode_fh(struct inode *inode, u32 *fh_in, int *max_len,
                           struct inode *parent)
{
        int len = *max_len;
        int type = 1;
        u64 blkno;
        u32 generation;
        __le32 *fh = (__force __le32 *) fh_in;

#ifdef TRACE_HOOKS_ARE_NOT_BRAINDEAD_IN_YOUR_OPINION
#error "You go ahead and fix that mess, then.  Somehow"
        trace_ocfs2_encode_fh_begin(dentry, dentry->d_name.len,
                                    dentry->d_name.name,
                                    fh, len, connectable);
#endif

        if (parent && (len < 6)) {
                *max_len = 6;
                type = FILEID_INVALID;
                goto bail;
        } else if (len < 3) {
                *max_len = 3;
                type = FILEID_INVALID;
                goto bail;
        }

        blkno = OCFS2_I(inode)->ip_blkno;
        generation = inode->i_generation;

        trace_ocfs2_encode_fh_self((unsigned long long)blkno, generation);

        len = 3;
        fh[0] = cpu_to_le32((u32)(blkno >> 32));
        fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
        fh[2] = cpu_to_le32(generation);

        if (parent) {
                blkno = OCFS2_I(parent)->ip_blkno;
                generation = parent->i_generation;

                fh[3] = cpu_to_le32((u32)(blkno >> 32));
                fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
                fh[5] = cpu_to_le32(generation);

                len = 6;
                type = 2;

                trace_ocfs2_encode_fh_parent((unsigned long long)blkno,
                                             generation);
        }

        *max_len = len;

bail:
        trace_ocfs2_encode_fh_type(type);
        return type;
}

static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,
                struct fid *fid, int fh_len, int fh_type)
{
        struct ocfs2_inode_handle handle;

        if (fh_len < 3 || fh_type > 2)
                return NULL;

        handle.ih_blkno = (u64)le32_to_cpu((__force __le32)fid->raw[0]) << 32;
        handle.ih_blkno |= (u64)le32_to_cpu((__force __le32)fid->raw[1]);
        handle.ih_generation = le32_to_cpu((__force __le32)fid->raw[2]);
        return ocfs2_get_dentry(sb, &handle);
}

static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,
                struct fid *fid, int fh_len, int fh_type)
{
        struct ocfs2_inode_handle parent;

        if (fh_type != 2 || fh_len < 6)
                return NULL;

        parent.ih_blkno = (u64)le32_to_cpu((__force __le32)fid->raw[3]) << 32;
        parent.ih_blkno |= (u64)le32_to_cpu((__force __le32)fid->raw[4]);
        parent.ih_generation = le32_to_cpu((__force __le32)fid->raw[5]);
        return ocfs2_get_dentry(sb, &parent);
}

const struct export_operations ocfs2_export_ops = {
        .encode_fh      = ocfs2_encode_fh,
        .fh_to_dentry   = ocfs2_fh_to_dentry,
        .fh_to_parent   = ocfs2_fh_to_parent,
        .get_parent     = ocfs2_get_parent,
};