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