LXR linux/fs/xfs/xfs

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2004-2005 Silicon Graphics, Inc.
   4 * All Rights Reserved.
   5 */
   6#include "xfs.h"
   7#include "xfs_format.h"
   8#include "xfs_log_format.h"
   9#include "xfs_trans_resv.h"
  10#include "xfs_mount.h"
  11#include "xfs_da_format.h"
  12#include "xfs_da_btree.h"
  13#include "xfs_dir2.h"
  14#include "xfs_export.h"
  15#include "xfs_inode.h"
  16#include "xfs_trans.h"
  17#include "xfs_inode_item.h"
  18#include "xfs_trace.h"
  19#include "xfs_icache.h"
  20#include "xfs_log.h"
  21#include "xfs_pnfs.h"
  22
  23/*
  24 * Note that we only accept fileids which are long enough rather than allow
  25 * the parent generation number to default to zero.  XFS considers zero a
  26 * valid generation number not an invalid/wildcard value.
  27 */
  28static int xfs_fileid_length(int fileid_type)
  29{
  30        switch (fileid_type) {
  31        case FILEID_INO32_GEN:
  32                return 2;
  33        case FILEID_INO32_GEN_PARENT:
  34                return 4;
  35        case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
  36                return 3;
  37        case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
  38                return 6;
  39        }
  40        return FILEID_INVALID;
  41}
  42
  43STATIC int
  44xfs_fs_encode_fh(
  45        struct inode    *inode,
  46        __u32           *fh,
  47        int             *max_len,
  48        struct inode    *parent)
  49{
  50        struct fid              *fid = (struct fid *)fh;
  51        struct xfs_fid64        *fid64 = (struct xfs_fid64 *)fh;
  52        int                     fileid_type;
  53        int                     len;
  54
  55        /* Directories don't need their parent encoded, they have ".." */
  56        if (!parent)
  57                fileid_type = FILEID_INO32_GEN;
  58        else
  59                fileid_type = FILEID_INO32_GEN_PARENT;
  60
  61        /*
  62         * If the the filesystem may contain 64bit inode numbers, we need
  63         * to use larger file handles that can represent them.
  64         *
  65         * While we only allocate inodes that do not fit into 32 bits any
  66         * large enough filesystem may contain them, thus the slightly
  67         * confusing looking conditional below.
  68         */
  69        if (!(XFS_M(inode->i_sb)->m_flags & XFS_MOUNT_SMALL_INUMS) ||
  70            (XFS_M(inode->i_sb)->m_flags & XFS_MOUNT_32BITINODES))
  71                fileid_type |= XFS_FILEID_TYPE_64FLAG;
  72
  73        /*
  74         * Only encode if there is enough space given.  In practice
  75         * this means we can't export a filesystem with 64bit inodes
  76         * over NFSv2 with the subtree_check export option; the other
  77         * seven combinations work.  The real answer is "don't use v2".
  78         */
  79        len = xfs_fileid_length(fileid_type);
  80        if (*max_len < len) {
  81                *max_len = len;
  82                return FILEID_INVALID;
  83        }
  84        *max_len = len;
  85
  86        switch (fileid_type) {
  87        case FILEID_INO32_GEN_PARENT:
  88                fid->i32.parent_ino = XFS_I(parent)->i_ino;
  89                fid->i32.parent_gen = parent->i_generation;
  90                /*FALLTHRU*/
  91        case FILEID_INO32_GEN:
  92                fid->i32.ino = XFS_I(inode)->i_ino;
  93                fid->i32.gen = inode->i_generation;
  94                break;
  95        case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
  96                fid64->parent_ino = XFS_I(parent)->i_ino;
  97                fid64->parent_gen = parent->i_generation;
  98                /*FALLTHRU*/
  99        case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
 100                fid64->ino = XFS_I(inode)->i_ino;
 101                fid64->gen = inode->i_generation;
 102                break;
 103        }
 104
 105        return fileid_type;
 106}
 107
 108STATIC struct inode *
 109xfs_nfs_get_inode(
 110        struct super_block      *sb,
 111        u64                     ino,
 112        u32                     generation)
 113{
 114        xfs_mount_t             *mp = XFS_M(sb);
 115        xfs_inode_t             *ip;
 116        int                     error;
 117
 118        /*
 119         * NFS can sometimes send requests for ino 0.  Fail them gracefully.
 120         */
 121        if (ino == 0)
 122                return ERR_PTR(-ESTALE);
 123
 124        /*
 125         * The XFS_IGET_UNTRUSTED means that an invalid inode number is just
 126         * fine and not an indication of a corrupted filesystem as clients can
 127         * send invalid file handles and we have to handle it gracefully..
 128         */
 129        error = xfs_iget(mp, NULL, ino, XFS_IGET_UNTRUSTED, 0, &ip);
 130        if (error) {
 131
 132                /*
 133                 * EINVAL means the inode cluster doesn't exist anymore.
 134                 * EFSCORRUPTED means the metadata pointing to the inode cluster
 135                 * or the inode cluster itself is corrupt.  This implies the
 136                 * filehandle is stale, so we should translate it here.
 137                 * We don't use ESTALE directly down the chain to not
 138                 * confuse applications using bulkstat that expect EINVAL.
 139                 */
 140                switch (error) {
 141                case -EINVAL:
 142                case -ENOENT:
 143                case -EFSCORRUPTED:
 144                        error = -ESTALE;
 145                        break;
 146                default:
 147                        break;
 148                }
 149                return ERR_PTR(error);
 150        }
 151
 152        if (VFS_I(ip)->i_generation != generation) {
 153                xfs_irele(ip);
 154                return ERR_PTR(-ESTALE);
 155        }
 156
 157        return VFS_I(ip);
 158}
 159
 160STATIC struct dentry *
 161xfs_fs_fh_to_dentry(struct super_block *sb, struct fid *fid,
 162                 int fh_len, int fileid_type)
 163{
 164        struct xfs_fid64        *fid64 = (struct xfs_fid64 *)fid;
 165        struct inode            *inode = NULL;
 166
 167        if (fh_len < xfs_fileid_length(fileid_type))
 168                return NULL;
 169
 170        switch (fileid_type) {
 171        case FILEID_INO32_GEN_PARENT:
 172        case FILEID_INO32_GEN:
 173                inode = xfs_nfs_get_inode(sb, fid->i32.ino, fid->i32.gen);
 174                break;
 175        case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
 176        case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
 177                inode = xfs_nfs_get_inode(sb, fid64->ino, fid64->gen);
 178                break;
 179        }
 180
 181        return d_obtain_alias(inode);
 182}
 183
 184STATIC struct dentry *
 185xfs_fs_fh_to_parent(struct super_block *sb, struct fid *fid,
 186                 int fh_len, int fileid_type)
 187{
 188        struct xfs_fid64        *fid64 = (struct xfs_fid64 *)fid;
 189        struct inode            *inode = NULL;
 190
 191        if (fh_len < xfs_fileid_length(fileid_type))
 192                return NULL;
 193
 194        switch (fileid_type) {
 195        case FILEID_INO32_GEN_PARENT:
 196                inode = xfs_nfs_get_inode(sb, fid->i32.parent_ino,
 197                                              fid->i32.parent_gen);
 198                break;
 199        case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
 200                inode = xfs_nfs_get_inode(sb, fid64->parent_ino,
 201                                              fid64->parent_gen);
 202                break;
 203        }
 204
 205        return d_obtain_alias(inode);
 206}
 207
 208STATIC struct dentry *
 209xfs_fs_get_parent(
 210        struct dentry           *child)
 211{
 212        int                     error;
 213        struct xfs_inode        *cip;
 214
 215        error = xfs_lookup(XFS_I(d_inode(child)), &xfs_name_dotdot, &cip, NULL);
 216        if (unlikely(error))
 217                return ERR_PTR(error);
 218
 219        return d_obtain_alias(VFS_I(cip));
 220}
 221
 222STATIC int
 223xfs_fs_nfs_commit_metadata(
 224        struct inode            *inode)
 225{
 226        struct xfs_inode        *ip = XFS_I(inode);
 227        struct xfs_mount        *mp = ip->i_mount;
 228        xfs_lsn_t               lsn = 0;
 229
 230        xfs_ilock(ip, XFS_ILOCK_SHARED);
 231        if (xfs_ipincount(ip))
 232                lsn = ip->i_itemp->ili_last_lsn;
 233        xfs_iunlock(ip, XFS_ILOCK_SHARED);
 234
 235        if (!lsn)
 236                return 0;
 237        return xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
 238}
 239
 240const struct export_operations xfs_export_operations = {
 241        .encode_fh              = xfs_fs_encode_fh,
 242        .fh_to_dentry           = xfs_fs_fh_to_dentry,
 243        .fh_to_parent           = xfs_fs_fh_to_parent,
 244        .get_parent             = xfs_fs_get_parent,
 245        .commit_metadata        = xfs_fs_nfs_commit_metadata,
 246#ifdef CONFIG_EXPORTFS_BLOCK_OPS
 247        .get_uuid               = xfs_fs_get_uuid,
 248        .map_blocks             = xfs_fs_map_blocks,
 249        .commit_blocks          = xfs_fs_commit_blocks,
 250#endif
 251};
 252