LXR linux/fs/xfs/xfs

   1/*
   2 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
   3 * All Rights Reserved.
   4 *
   5 * This program is free software; you can redistribute it and/or
   6 * modify it under the terms of the GNU General Public License as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it would be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write the Free Software Foundation,
  16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17 */
  18#include "xfs.h"
  19#include "xfs_fs.h"
  20#include "xfs_types.h"
  21#include "xfs_bit.h"
  22#include "xfs_log.h"
  23#include "xfs_inum.h"
  24#include "xfs_trans.h"
  25#include "xfs_sb.h"
  26#include "xfs_ag.h"
  27#include "xfs_mount.h"
  28#include "xfs_bmap_btree.h"
  29#include "xfs_dinode.h"
  30#include "xfs_inode.h"
  31#include "xfs_inode_item.h"
  32#include "xfs_bmap.h"
  33#include "xfs_itable.h"
  34#include "xfs_dfrag.h"
  35#include "xfs_error.h"
  36#include "xfs_vnodeops.h"
  37#include "xfs_trace.h"
  38
  39
  40static int xfs_swap_extents(
  41        xfs_inode_t     *ip,    /* target inode */
  42        xfs_inode_t     *tip,   /* tmp inode */
  43        xfs_swapext_t   *sxp);
  44
  45/*
  46 * ioctl interface for swapext
  47 */
  48int
  49xfs_swapext(
  50        xfs_swapext_t   *sxp)
  51{
  52        xfs_inode_t     *ip, *tip;
  53        struct file     *file, *tmp_file;
  54        int             error = 0;
  55
  56        /* Pull information for the target fd */
  57        file = fget((int)sxp->sx_fdtarget);
  58        if (!file) {
  59                error = XFS_ERROR(EINVAL);
  60                goto out;
  61        }
  62
  63        if (!(file->f_mode & FMODE_WRITE) ||
  64            !(file->f_mode & FMODE_READ) ||
  65            (file->f_flags & O_APPEND)) {
  66                error = XFS_ERROR(EBADF);
  67                goto out_put_file;
  68        }
  69
  70        tmp_file = fget((int)sxp->sx_fdtmp);
  71        if (!tmp_file) {
  72                error = XFS_ERROR(EINVAL);
  73                goto out_put_file;
  74        }
  75
  76        if (!(tmp_file->f_mode & FMODE_WRITE) ||
  77            !(tmp_file->f_mode & FMODE_READ) ||
  78            (tmp_file->f_flags & O_APPEND)) {
  79                error = XFS_ERROR(EBADF);
  80                goto out_put_tmp_file;
  81        }
  82
  83        if (IS_SWAPFILE(file->f_path.dentry->d_inode) ||
  84            IS_SWAPFILE(tmp_file->f_path.dentry->d_inode)) {
  85                error = XFS_ERROR(EINVAL);
  86                goto out_put_tmp_file;
  87        }
  88
  89        ip = XFS_I(file->f_path.dentry->d_inode);
  90        tip = XFS_I(tmp_file->f_path.dentry->d_inode);
  91
  92        if (ip->i_mount != tip->i_mount) {
  93                error = XFS_ERROR(EINVAL);
  94                goto out_put_tmp_file;
  95        }
  96
  97        if (ip->i_ino == tip->i_ino) {
  98                error = XFS_ERROR(EINVAL);
  99                goto out_put_tmp_file;
 100        }
 101
 102        if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
 103                error = XFS_ERROR(EIO);
 104                goto out_put_tmp_file;
 105        }
 106
 107        error = xfs_swap_extents(ip, tip, sxp);
 108
 109 out_put_tmp_file:
 110        fput(tmp_file);
 111 out_put_file:
 112        fput(file);
 113 out:
 114        return error;
 115}
 116
 117/*
 118 * We need to check that the format of the data fork in the temporary inode is
 119 * valid for the target inode before doing the swap. This is not a problem with
 120 * attr1 because of the fixed fork offset, but attr2 has a dynamically sized
 121 * data fork depending on the space the attribute fork is taking so we can get
 122 * invalid formats on the target inode.
 123 *
 124 * E.g. target has space for 7 extents in extent format, temp inode only has
 125 * space for 6.  If we defragment down to 7 extents, then the tmp format is a
 126 * btree, but when swapped it needs to be in extent format. Hence we can't just
 127 * blindly swap data forks on attr2 filesystems.
 128 *
 129 * Note that we check the swap in both directions so that we don't end up with
 130 * a corrupt temporary inode, either.
 131 *
 132 * Note that fixing the way xfs_fsr sets up the attribute fork in the source
 133 * inode will prevent this situation from occurring, so all we do here is
 134 * reject and log the attempt. basically we are putting the responsibility on
 135 * userspace to get this right.
 136 */
 137static int
 138xfs_swap_extents_check_format(
 139        xfs_inode_t     *ip,    /* target inode */
 140        xfs_inode_t     *tip)   /* tmp inode */
 141{
 142
 143        /* Should never get a local format */
 144        if (ip->i_d.di_format == XFS_DINODE_FMT_LOCAL ||
 145            tip->i_d.di_format == XFS_DINODE_FMT_LOCAL)
 146                return EINVAL;
 147
 148        /*
 149         * if the target inode has less extents that then temporary inode then
 150         * why did userspace call us?
 151         */
 152        if (ip->i_d.di_nextents < tip->i_d.di_nextents)
 153                return EINVAL;
 154
 155        /*
 156         * if the target inode is in extent form and the temp inode is in btree
 157         * form then we will end up with the target inode in the wrong format
 158         * as we already know there are less extents in the temp inode.
 159         */
 160        if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
 161            tip->i_d.di_format == XFS_DINODE_FMT_BTREE)
 162                return EINVAL;
 163
 164        /* Check temp in extent form to max in target */
 165        if (tip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
 166            XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) > ip->i_df.if_ext_max)
 167                return EINVAL;
 168
 169        /* Check target in extent form to max in temp */
 170        if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
 171            XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) > tip->i_df.if_ext_max)
 172                return EINVAL;
 173
 174        /*
 175         * If we are in a btree format, check that the temp root block will fit
 176         * in the target and that it has enough extents to be in btree format
 177         * in the target.
 178         *
 179         * Note that we have to be careful to allow btree->extent conversions
 180         * (a common defrag case) which will occur when the temp inode is in
 181         * extent format...
 182         */
 183        if (tip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
 184            ((XFS_IFORK_BOFF(ip) &&
 185              tip->i_df.if_broot_bytes > XFS_IFORK_BOFF(ip)) ||
 186             XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) <= ip->i_df.if_ext_max))
 187                return EINVAL;
 188
 189        /* Reciprocal target->temp btree format checks */
 190        if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
 191            ((XFS_IFORK_BOFF(tip) &&
 192              ip->i_df.if_broot_bytes > XFS_IFORK_BOFF(tip)) ||
 193             XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) <= tip->i_df.if_ext_max))
 194                return EINVAL;
 195
 196        return 0;
 197}
 198
 199static int
 200xfs_swap_extents(
 201        xfs_inode_t     *ip,    /* target inode */
 202        xfs_inode_t     *tip,   /* tmp inode */
 203        xfs_swapext_t   *sxp)
 204{
 205        xfs_mount_t     *mp;
 206        xfs_trans_t     *tp;
 207        xfs_bstat_t     *sbp = &sxp->sx_stat;
 208        xfs_ifork_t     *tempifp, *ifp, *tifp;
 209        int             ilf_fields, tilf_fields;
 210        int             error = 0;
 211        int             aforkblks = 0;
 212        int             taforkblks = 0;
 213        __uint64_t      tmp;
 214
 215        mp = ip->i_mount;
 216
 217        tempifp = kmem_alloc(sizeof(xfs_ifork_t), KM_MAYFAIL);
 218        if (!tempifp) {
 219                error = XFS_ERROR(ENOMEM);
 220                goto out;
 221        }
 222
 223        sbp = &sxp->sx_stat;
 224
 225        /*
 226         * we have to do two separate lock calls here to keep lockdep
 227         * happy. If we try to get all the locks in one call, lock will
 228         * report false positives when we drop the ILOCK and regain them
 229         * below.
 230         */
 231        xfs_lock_two_inodes(ip, tip, XFS_IOLOCK_EXCL);
 232        xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
 233
 234        /* Verify that both files have the same format */
 235        if ((ip->i_d.di_mode & S_IFMT) != (tip->i_d.di_mode & S_IFMT)) {
 236                error = XFS_ERROR(EINVAL);
 237                goto out_unlock;
 238        }
 239
 240        /* Verify both files are either real-time or non-realtime */
 241        if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {
 242                error = XFS_ERROR(EINVAL);
 243                goto out_unlock;
 244        }
 245
 246        if (VN_CACHED(VFS_I(tip)) != 0) {
 247                error = xfs_flushinval_pages(tip, 0, -1,
 248                                FI_REMAPF_LOCKED);
 249                if (error)
 250                        goto out_unlock;
 251        }
 252
 253        /* Verify O_DIRECT for ftmp */
 254        if (VN_CACHED(VFS_I(tip)) != 0) {
 255                error = XFS_ERROR(EINVAL);
 256                goto out_unlock;
 257        }
 258
 259        /* Verify all data are being swapped */
 260        if (sxp->sx_offset != 0 ||
 261            sxp->sx_length != ip->i_d.di_size ||
 262            sxp->sx_length != tip->i_d.di_size) {
 263                error = XFS_ERROR(EFAULT);
 264                goto out_unlock;
 265        }
 266
 267        trace_xfs_swap_extent_before(ip, 0);
 268        trace_xfs_swap_extent_before(tip, 1);
 269
 270        /* check inode formats now that data is flushed */
 271        error = xfs_swap_extents_check_format(ip, tip);
 272        if (error) {
 273                xfs_fs_cmn_err(CE_NOTE, mp,
 274                    "%s: inode 0x%llx format is incompatible for exchanging.",
 275                                __FILE__, ip->i_ino);
 276                goto out_unlock;
 277        }
 278
 279        /*
 280         * Compare the current change & modify times with that
 281         * passed in.  If they differ, we abort this swap.
 282         * This is the mechanism used to ensure the calling
 283         * process that the file was not changed out from
 284         * under it.
 285         */
 286        if ((sbp->bs_ctime.tv_sec != VFS_I(ip)->i_ctime.tv_sec) ||
 287            (sbp->bs_ctime.tv_nsec != VFS_I(ip)->i_ctime.tv_nsec) ||
 288            (sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
 289            (sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
 290                error = XFS_ERROR(EBUSY);
 291                goto out_unlock;
 292        }
 293
 294        /* We need to fail if the file is memory mapped.  Once we have tossed
 295         * all existing pages, the page fault will have no option
 296         * but to go to the filesystem for pages. By making the page fault call
 297         * vop_read (or write in the case of autogrow) they block on the iolock
 298         * until we have switched the extents.
 299         */
 300        if (VN_MAPPED(VFS_I(ip))) {
 301                error = XFS_ERROR(EBUSY);
 302                goto out_unlock;
 303        }
 304
 305        xfs_iunlock(ip, XFS_ILOCK_EXCL);
 306        xfs_iunlock(tip, XFS_ILOCK_EXCL);
 307
 308        /*
 309         * There is a race condition here since we gave up the
 310         * ilock.  However, the data fork will not change since
 311         * we have the iolock (locked for truncation too) so we
 312         * are safe.  We don't really care if non-io related
 313         * fields change.
 314         */
 315
 316        xfs_tosspages(ip, 0, -1, FI_REMAPF);
 317
 318        tp = xfs_trans_alloc(mp, XFS_TRANS_SWAPEXT);
 319        if ((error = xfs_trans_reserve(tp, 0,
 320                                     XFS_ICHANGE_LOG_RES(mp), 0,
 321                                     0, 0))) {
 322                xfs_iunlock(ip,  XFS_IOLOCK_EXCL);
 323                xfs_iunlock(tip, XFS_IOLOCK_EXCL);
 324                xfs_trans_cancel(tp, 0);
 325                goto out;
 326        }
 327        xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
 328
 329        /*
 330         * Count the number of extended attribute blocks
 331         */
 332        if ( ((XFS_IFORK_Q(ip) != 0) && (ip->i_d.di_anextents > 0)) &&
 333             (ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)) {
 334                error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK, &aforkblks);
 335                if (error)
 336                        goto out_trans_cancel;
 337        }
 338        if ( ((XFS_IFORK_Q(tip) != 0) && (tip->i_d.di_anextents > 0)) &&
 339             (tip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)) {
 340                error = xfs_bmap_count_blocks(tp, tip, XFS_ATTR_FORK,
 341                        &taforkblks);
 342                if (error)
 343                        goto out_trans_cancel;
 344        }
 345
 346        /*
 347         * Swap the data forks of the inodes
 348         */
 349        ifp = &ip->i_df;
 350        tifp = &tip->i_df;
 351        *tempifp = *ifp;        /* struct copy */
 352        *ifp = *tifp;           /* struct copy */
 353        *tifp = *tempifp;       /* struct copy */
 354
 355        /*
 356         * Fix the in-memory data fork values that are dependent on the fork
 357         * offset in the inode. We can't assume they remain the same as attr2
 358         * has dynamic fork offsets.
 359         */
 360        ifp->if_ext_max = XFS_IFORK_SIZE(ip, XFS_DATA_FORK) /
 361                                        (uint)sizeof(xfs_bmbt_rec_t);
 362        tifp->if_ext_max = XFS_IFORK_SIZE(tip, XFS_DATA_FORK) /
 363                                        (uint)sizeof(xfs_bmbt_rec_t);
 364
 365        /*
 366         * Fix the on-disk inode values
 367         */
 368        tmp = (__uint64_t)ip->i_d.di_nblocks;
 369        ip->i_d.di_nblocks = tip->i_d.di_nblocks - taforkblks + aforkblks;
 370        tip->i_d.di_nblocks = tmp + taforkblks - aforkblks;
 371
 372        tmp = (__uint64_t) ip->i_d.di_nextents;
 373        ip->i_d.di_nextents = tip->i_d.di_nextents;
 374        tip->i_d.di_nextents = tmp;
 375
 376        tmp = (__uint64_t) ip->i_d.di_format;
 377        ip->i_d.di_format = tip->i_d.di_format;
 378        tip->i_d.di_format = tmp;
 379
 380        /*
 381         * The extents in the source inode could still contain speculative
 382         * preallocation beyond EOF (e.g. the file is open but not modified
 383         * while defrag is in progress). In that case, we need to copy over the
 384         * number of delalloc blocks the data fork in the source inode is
 385         * tracking beyond EOF so that when the fork is truncated away when the
 386         * temporary inode is unlinked we don't underrun the i_delayed_blks
 387         * counter on that inode.
 388         */
 389        ASSERT(tip->i_delayed_blks == 0);
 390        tip->i_delayed_blks = ip->i_delayed_blks;
 391        ip->i_delayed_blks = 0;
 392
 393        ilf_fields = XFS_ILOG_CORE;
 394
 395        switch(ip->i_d.di_format) {
 396        case XFS_DINODE_FMT_EXTENTS:
 397                /* If the extents fit in the inode, fix the
 398                 * pointer.  Otherwise it's already NULL or
 399                 * pointing to the extent.
 400                 */
 401                if (ip->i_d.di_nextents <= XFS_INLINE_EXTS) {
 402                        ifp->if_u1.if_extents =
 403                                ifp->if_u2.if_inline_ext;
 404                }
 405                ilf_fields |= XFS_ILOG_DEXT;
 406                break;
 407        case XFS_DINODE_FMT_BTREE:
 408                ilf_fields |= XFS_ILOG_DBROOT;
 409                break;
 410        }
 411
 412        tilf_fields = XFS_ILOG_CORE;
 413
 414        switch(tip->i_d.di_format) {
 415        case XFS_DINODE_FMT_EXTENTS:
 416                /* If the extents fit in the inode, fix the
 417                 * pointer.  Otherwise it's already NULL or
 418                 * pointing to the extent.
 419                 */
 420                if (tip->i_d.di_nextents <= XFS_INLINE_EXTS) {
 421                        tifp->if_u1.if_extents =
 422                                tifp->if_u2.if_inline_ext;
 423                }
 424                tilf_fields |= XFS_ILOG_DEXT;
 425                break;
 426        case XFS_DINODE_FMT_BTREE:
 427                tilf_fields |= XFS_ILOG_DBROOT;
 428                break;
 429        }
 430
 431
 432        xfs_trans_ijoin_ref(tp, ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 433        xfs_trans_ijoin_ref(tp, tip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 434
 435        xfs_trans_log_inode(tp, ip,  ilf_fields);
 436        xfs_trans_log_inode(tp, tip, tilf_fields);
 437
 438        /*
 439         * If this is a synchronous mount, make sure that the
 440         * transaction goes to disk before returning to the user.
 441         */
 442        if (mp->m_flags & XFS_MOUNT_WSYNC)
 443                xfs_trans_set_sync(tp);
 444
 445        error = xfs_trans_commit(tp, XFS_TRANS_SWAPEXT);
 446
 447        trace_xfs_swap_extent_after(ip, 0);
 448        trace_xfs_swap_extent_after(tip, 1);
 449out:
 450        kmem_free(tempifp);
 451        return error;
 452
 453out_unlock:
 454        xfs_iunlock(ip,  XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 455        xfs_iunlock(tip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 456        goto out;
 457
 458out_trans_cancel:
 459        xfs_trans_cancel(tp, 0);
 460        goto out_unlock;
 461}
 462