ldiskfs/kernel_patches/patches/ext4-mmp-rhel5.patch

   1 Index: linux-2.6.18-128.1.6/fs/ext4/super.c
   2 ===================================================================
   3 --- linux-2.6.18-128.1.6.orig/fs/ext4/super.c
   4 +++ linux-2.6.18-128.1.6/fs/ext4/super.c
   5 @@ -36,6 +36,8 @@
   6  #include <linux/log2.h>
   7  #include <linux/crc16.h>
   8  #include <asm/uaccess.h>
   9 +#include <linux/kthread.h>
  10 +#include <linux/utsname.h>
  11
  12  #include "ext4.h"
  13  #include "ext4_jbd2.h"
  14 @@ -547,6 +549,8 @@ static void ext4_put_super(struct super_
  15                 invalidate_bdev(sbi->journal_bdev, 0);
  16                 ext4_blkdev_remove(sbi);
  17         }
  18 +       if (sbi->s_mmp_tsk)
  19 +               kthread_stop(sbi->s_mmp_tsk);
  20         sb->s_fs_info = NULL;
  21         kfree(sbi);
  22         return;
  23 @@ -766,6 +770,328 @@ static int ext4_show_options(struct seq_
  24         return 0;
  25  }
  26
  27 +/*
  28 + * Write the MMP block using WRITE_SYNC to try to get the block on-disk
  29 + * faster.
  30 + */
  31 +static int write_mmp_block(struct buffer_head *bh)
  32 +{
  33 +       mark_buffer_dirty(bh);
  34 +       lock_buffer(bh);
  35 +       bh->b_end_io = end_buffer_write_sync;
  36 +       get_bh(bh);
  37 +       submit_bh(WRITE_SYNC, bh);
  38 +       wait_on_buffer(bh);
  39 +       if (unlikely(!buffer_uptodate(bh)))
  40 +               return 1;
  41 +
  42 +       return 0;
  43 +}
  44 +
  45 +/*
  46 + * Read the MMP block. It _must_ be read from disk and hence we clear the
  47 + * uptodate flag on the buffer.
  48 + */
  49 +static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
  50 +                         unsigned long mmp_block)
  51 +{
  52 +       struct mmp_struct *mmp;
  53 +
  54 +       if (*bh)
  55 +               clear_buffer_uptodate(*bh);
  56 +
  57 +#if 0
  58 +       brelse(*bh);
  59 +
  60 +       *bh = sb_bread(sb, mmp_block);
  61 +#else
  62 +       if (!*bh)
  63 +               *bh = sb_getblk(sb, mmp_block);
  64 +       if (*bh) {
  65 +               get_bh(*bh);
  66 +               lock_buffer(*bh);
  67 +               (*bh)->b_end_io = end_buffer_read_sync;
  68 +               submit_bh(READ_SYNC, *bh);
  69 +               wait_on_buffer(*bh);
  70 +               if (!buffer_uptodate(*bh)) {
  71 +                       brelse(*bh);
  72 +                       *bh = NULL;
  73 +               }
  74 +       }
  75 +#endif
  76 +       if (!*bh) {
  77 +               ext4_warning(sb, __FUNCTION__,
  78 +                            "Error while reading MMP block %lu", mmp_block);
  79 +               return -EIO;
  80 +       }
  81 +
  82 +       mmp = (struct mmp_struct *)((*bh)->b_data);
  83 +       if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC)
  84 +               return -EINVAL;
  85 +
  86 +       return 0;
  87 +}
  88 +
  89 +/*
  90 + * Dump as much information as possible to help the admin.
  91 + */
  92 +static void dump_mmp_msg(struct super_block *sb, struct mmp_struct *mmp,
  93 +                        const char *function, const char *msg)
  94 +{
  95 +       ext4_warning(sb, function, msg);
  96 +       ext4_warning(sb, function, "MMP failure info: last update time: %llu, "
  97 +                    "last update node: %s, last update device: %s\n",
  98 +                    le64_to_cpu(mmp->mmp_time), mmp->mmp_nodename,
  99 +                    mmp->mmp_bdevname);
 100 +}
 101 +
 102 +/*
 103 + * kmmpd will update the MMP sequence every s_mmp_update_interval seconds
 104 + */
 105 +static int kmmpd(void *data)
 106 +{
 107 +       struct super_block *sb = (struct super_block *) data;
 108 +       struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 109 +       struct buffer_head *bh = NULL;
 110 +       struct mmp_struct *mmp;
 111 +       unsigned long mmp_block;
 112 +       u32 seq = 0;
 113 +       unsigned long failed_writes = 0;
 114 +       int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval);
 115 +       unsigned mmp_check_interval;
 116 +       unsigned long last_update_time;
 117 +       unsigned long diff;
 118 +       int retval;
 119 +
 120 +       mmp_block = le64_to_cpu(es->s_mmp_block);
 121 +       retval = read_mmp_block(sb, &bh, mmp_block);
 122 +       if (retval)
 123 +               goto failed;
 124 +
 125 +       mmp = (struct mmp_struct *)(bh->b_data);
 126 +       mmp->mmp_time = cpu_to_le64(get_seconds());
 127 +       /*
 128 +        * Start with the higher mmp_check_interval and reduce it if
 129 +        * the MMP block is being updated on time.
 130 +        */
 131 +       mmp_check_interval = max(5 * mmp_update_interval,
 132 +                                EXT4_MMP_MIN_CHECK_INTERVAL);
 133 +       mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
 134 +       bdevname(bh->b_bdev, mmp->mmp_bdevname);
 135 +
 136 +       down_read(&uts_sem);
 137 +       memcpy(mmp->mmp_nodename, system_utsname.nodename,
 138 +              sizeof(mmp->mmp_nodename));
 139 +       up_read(&uts_sem);
 140 +
 141 +       while (!kthread_should_stop()) {
 142 +               if (++seq > EXT4_MMP_SEQ_MAX)
 143 +                       seq = 1;
 144 +
 145 +               mmp->mmp_seq = cpu_to_le32(seq);
 146 +               mmp->mmp_time = cpu_to_le64(get_seconds());
 147 +               last_update_time = jiffies;
 148 +
 149 +               retval = write_mmp_block(bh);
 150 +               /*
 151 +                * Don't spew too many error messages. Print one every
 152 +                * (s_mmp_update_interval * 60) seconds.
 153 +                */
 154 +               if (retval && (failed_writes % 60) == 0) {
 155 +                       ext4_error(sb, __FUNCTION__,
 156 +                                  "Error writing to MMP block");
 157 +                       failed_writes++;
 158 +               }
 159 +
 160 +               if (!(le32_to_cpu(es->s_feature_incompat) &
 161 +                   EXT4_FEATURE_INCOMPAT_MMP)) {
 162 +                       ext4_warning(sb, __FUNCTION__, "kmmpd being stopped "
 163 +                                    "since MMP feature has been disabled.");
 164 +                       EXT4_SB(sb)->s_mmp_tsk = 0;
 165 +                       goto failed;
 166 +               }
 167 +
 168 +               if (sb->s_flags & MS_RDONLY) {
 169 +                       ext4_warning(sb, __FUNCTION__, "kmmpd being stopped "
 170 +                                    "since filesystem has been remounted as "
 171 +                                    "readonly.");
 172 +                       EXT4_SB(sb)->s_mmp_tsk = 0;
 173 +                       goto failed;
 174 +               }
 175 +
 176 +               diff = jiffies - last_update_time;
 177 +               if (diff < mmp_update_interval * HZ)
 178 +                       schedule_timeout_interruptible(EXT4_MMP_UPDATE_INTERVAL*
 179 +                                                      HZ - diff);
 180 +
 181 +               /*
 182 +                * We need to make sure that more than mmp_check_interval
 183 +                * seconds have not passed since writing. If that has happened
 184 +                * we need to check if the MMP block is as we left it.
 185 +                */
 186 +               diff = jiffies - last_update_time;
 187 +               if (diff > mmp_check_interval * HZ) {
 188 +                       struct buffer_head *bh_check = NULL;
 189 +                       struct mmp_struct *mmp_check;
 190 +
 191 +                       retval = read_mmp_block(sb, &bh_check, mmp_block);
 192 +                       if (retval) {
 193 +                               EXT4_SB(sb)->s_mmp_tsk = 0;
 194 +                               goto failed;
 195 +                       }
 196 +
 197 +                       mmp_check = (struct mmp_struct *)(bh_check->b_data);
 198 +                       if (mmp->mmp_time != mmp_check->mmp_time ||
 199 +                           memcmp(mmp->mmp_nodename, mmp_check->mmp_nodename,
 200 +                                  sizeof(mmp->mmp_nodename)))
 201 +                               dump_mmp_msg(sb, mmp_check, __FUNCTION__,
 202 +                                            "Error while updating MMP info. "
 203 +                                            "The filesystem seems to have "
 204 +                                            "been multiply mounted.");
 205 +
 206 +                       put_bh(bh_check);
 207 +               }
 208 +
 209 +               /*
 210 +                * Adjust the mmp_check_interval depending on how much time
 211 +                * it took for the MMP block to be written.
 212 +                */
 213 +               mmp_check_interval = max(5 * diff / HZ,
 214 +                                (unsigned long) EXT4_MMP_MIN_CHECK_INTERVAL);
 215 +               mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
 216 +       }
 217 +
 218 +       /*
 219 +        * Unmount seems to be clean.
 220 +        */
 221 +       mmp->mmp_seq = cpu_to_le32(EXT4_MMP_SEQ_CLEAN);
 222 +       mmp->mmp_time = cpu_to_le64(get_seconds());
 223 +
 224 +       retval = write_mmp_block(bh);
 225 +
 226 +failed:
 227 +       brelse(bh);
 228 +       return retval;
 229 +}
 230 +
 231 +/*
 232 + * Get a random new sequence number but make sure it is not greater than
 233 + * EXT4_MMP_SEQ_MAX.
 234 + */
 235 +static unsigned int mmp_new_seq(void)
 236 +{
 237 +       u32 new_seq;
 238 +
 239 +       do {
 240 +               get_random_bytes(&new_seq, sizeof(u32));
 241 +       } while (new_seq > EXT4_MMP_SEQ_MAX);
 242 +
 243 +       return new_seq;
 244 +}
 245 +
 246 +/*
 247 + * Protect the filesystem from being mounted more than once.
 248 + */
 249 +static int ext4_multi_mount_protect(struct super_block *sb,
 250 +                                   unsigned long mmp_block)
 251 +{
 252 +       struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 253 +       struct buffer_head *bh = NULL;
 254 +       struct mmp_struct *mmp = NULL;
 255 +       u32 seq;
 256 +       unsigned int mmp_check_interval = le16_to_cpu(es->s_mmp_update_interval);
 257 +       int retval;
 258 +
 259 +       if (mmp_block < le32_to_cpu(es->s_first_data_block) ||
 260 +           mmp_block >= ext4_blocks_count(es)) {
 261 +               ext4_warning(sb, __FUNCTION__,
 262 +                            "Invalid MMP block in superblock");
 263 +               goto failed;
 264 +       }
 265 +
 266 +       retval = read_mmp_block(sb, &bh, mmp_block);
 267 +       if (retval)
 268 +               goto failed;
 269 +
 270 +       mmp = (struct mmp_struct *)(bh->b_data);
 271 +
 272 +       if (mmp_check_interval < EXT4_MMP_MIN_CHECK_INTERVAL)
 273 +               mmp_check_interval = EXT4_MMP_MIN_CHECK_INTERVAL;
 274 +
 275 +       /*
 276 +        * If check_interval in MMP block is larger, use that instead of
 277 +        * update_interval from the superblock.
 278 +        */
 279 +       if (mmp->mmp_check_interval > mmp_check_interval)
 280 +               mmp_check_interval = mmp->mmp_check_interval;
 281 +
 282 +       seq = le32_to_cpu(mmp->mmp_seq);
 283 +       if (seq == EXT4_MMP_SEQ_CLEAN)
 284 +               goto skip;
 285 +
 286 +       if (seq == EXT4_MMP_SEQ_FSCK) {
 287 +               dump_mmp_msg(sb, mmp, __FUNCTION__,
 288 +                            "fsck is running on the filesystem");
 289 +               goto failed;
 290 +       }
 291 +
 292 +       schedule_timeout_uninterruptible(HZ * (2 * mmp_check_interval + 1));
 293 +
 294 +       retval = read_mmp_block(sb, &bh, mmp_block);
 295 +       if (retval)
 296 +               goto failed;
 297 +       mmp = (struct mmp_struct *)(bh->b_data);
 298 +       if (seq != le32_to_cpu(mmp->mmp_seq)) {
 299 +               dump_mmp_msg(sb, mmp, __FUNCTION__,
 300 +                            "Device is already active on another node.");
 301 +               goto failed;
 302 +       }
 303 +
 304 +skip:
 305 +       /*
 306 +        * write a new random sequence number.
 307 +        */
 308 +       mmp->mmp_seq = seq = cpu_to_le32(mmp_new_seq());
 309 +
 310 +       retval = write_mmp_block(bh);
 311 +       if (retval)
 312 +               goto failed;
 313 +
 314 +       /*
 315 +        * wait for MMP interval and check mmp_seq.
 316 +        */
 317 +       schedule_timeout_uninterruptible(HZ * (2 * mmp_check_interval + 1));
 318 +
 319 +       retval = read_mmp_block(sb, &bh, mmp_block);
 320 +       if (retval)
 321 +               goto failed;
 322 +       mmp = (struct mmp_struct *)(bh->b_data);
 323 +       if (seq != le32_to_cpu(mmp->mmp_seq)) {
 324 +               dump_mmp_msg(sb, mmp, __FUNCTION__,
 325 +                            "Device is already active on another node.");
 326 +               goto failed;
 327 +       }
 328 +
 329 +       /*
 330 +        * Start a kernel thread to update the MMP block periodically.
 331 +        */
 332 +       EXT4_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, sb, "kmmpd-%02x:%02x",
 333 +                                            MAJOR(sb->s_dev),
 334 +                                            MINOR(sb->s_dev));
 335 +       if (IS_ERR(EXT4_SB(sb)->s_mmp_tsk)) {
 336 +               EXT4_SB(sb)->s_mmp_tsk = 0;
 337 +               ext4_warning(sb, __FUNCTION__, "Unable to create kmmpd thread "
 338 +                            "for %s.", sb->s_id);
 339 +               goto failed;
 340 +       }
 341 +
 342 +       brelse(bh);
 343 +       return 0;
 344 +
 345 +failed:
 346 +       brelse(bh);
 347 +       return 1;
 348 +}
 349
 350  static struct dentry *ext4_get_dentry(struct super_block *sb, void *vobjp)
 351  {
 352 @@ -775,7 +1101,6 @@ static struct dentry *ext4_get_dentry(st
 353         struct inode *inode;
 354         struct dentry *result;
 355
 356 -
 357         if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
 358                 return ERR_PTR(-ESTALE);
 359         if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
 360 @@ -2258,6 +2583,11 @@ static int ext4_fill_super(struct super_
 361                           EXT4_HAS_INCOMPAT_FEATURE(sb,
 362                                     EXT4_FEATURE_INCOMPAT_RECOVER));
 363
 364 +       if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_MMP) &&
 365 +           !(sb->s_flags & MS_RDONLY))
 366 +               if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
 367 +                       goto failed_mount3;
 368 +
 369         /*
 370          * The first inode we look at is the journal inode.  Don't try
 371          * root first: it may be modified in the journal!
 372 @@ -2445,6 +2775,8 @@ failed_mount3:
 373         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 374         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 375         percpu_counter_destroy(&sbi->s_dirs_counter);
 376 +       if (sbi->s_mmp_tsk)
 377 +               kthread_stop(sbi->s_mmp_tsk);
 378  failed_mount2:
 379         for (i = 0; i < db_count; i++)
 380                 brelse(sbi->s_group_desc[i]);
 381 @@ -2918,7 +3250,7 @@ static int ext4_remount(struct super_blo
 382         unsigned long old_sb_flags;
 383         struct ext4_mount_options old_opts;
 384         ext4_group_t g;
 385 -       int err;
 386 +       int err = 0;
 387  #ifdef CONFIG_QUOTA
 388         int i;
 389  #endif
 390 @@ -3042,6 +3374,13 @@ static int ext4_remount(struct super_blo
 391                                 goto restore_opts;
 392                         if (!ext4_setup_super(sb, es, 0))
 393                                 sb->s_flags &= ~MS_RDONLY;
 394 +                       if (EXT4_HAS_INCOMPAT_FEATURE(sb,
 395 +                                                   EXT4_FEATURE_INCOMPAT_MMP))
 396 +                               if (ext4_multi_mount_protect(sb,
 397 +                                               le64_to_cpu(es->s_mmp_block))) {
 398 +                                       err = -EROFS;
 399 +                                       goto restore_opts;
 400 +                               }
 401                 }
 402         }
 403  #ifdef CONFIG_QUOTA
 404 Index: linux-2.6.18-128.1.6/fs/ext4/ext4.h
 405 ===================================================================
 406 --- linux-2.6.18-128.1.6.orig/fs/ext4/ext4.h
 407 +++ linux-2.6.18-128.1.6/fs/ext4/ext4.h
 408 @@ -658,7 +658,7 @@ struct ext4_super_block {
 409         __le16  s_want_extra_isize;     /* New inodes should reserve # bytes */
 410         __le32  s_flags;                /* Miscellaneous flags */
 411         __le16  s_raid_stride;          /* RAID stride */
 412 -       __le16  s_mmp_interval;         /* # seconds to wait in MMP checking */
 413 +       __le16  s_mmp_update_interval;  /* # seconds to wait in MMP checking */
 414         __le64  s_mmp_block;            /* Block for multi-mount protection */
 415         __le32  s_raid_stripe_width;    /* blocks on all data disks (N*stride)*/
 416         __u8    s_log_groups_per_flex;  /* FLEX_BG group size */
 417 @@ -775,7 +775,8 @@ static inline int ext4_valid_inum(struct
 418                                          EXT4_FEATURE_INCOMPAT_META_BG| \
 419                                          EXT4_FEATURE_INCOMPAT_EXTENTS| \
 420                                          EXT4_FEATURE_INCOMPAT_64BIT| \
 421 -                                        EXT4_FEATURE_INCOMPAT_FLEX_BG)
 422 +                                        EXT4_FEATURE_INCOMPAT_FLEX_BG| \
 423 +                                        EXT4_FEATURE_INCOMPAT_MMP)
 424  #define EXT4_FEATURE_RO_COMPAT_SUPP    (EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 425                                          EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
 426                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
 427 @@ -956,6 +957,39 @@ void ext4_get_group_no_and_offset(struct
 428                         unsigned long *blockgrpp, ext4_grpblk_t *offsetp);
 429
 430  /*
 431 + * This structure will be used for multiple mount protection. It will be
 432 + * written into the block number saved in the s_mmp_block field in the
 433 + * superblock. Programs that check MMP should assume that if
 434 + * SEQ_FSCK (or any unknown code above SEQ_MAX) is present then it is NOT safe
 435 + * to use the filesystem, regardless of how old the timestamp is.
 436 + */
 437 +#define EXT4_MMP_MAGIC     0x004D4D50U /* ASCII for MMP */
 438 +#define EXT4_MMP_SEQ_CLEAN 0xFF4D4D50U /* mmp_seq value for clean unmount */
 439 +#define EXT4_MMP_SEQ_FSCK  0xE24D4D50U /* mmp_seq value when being fscked */
 440 +#define EXT4_MMP_SEQ_MAX   0xE24D4D4FU /* maximum valid mmp_seq value */
 441 +
 442 +struct mmp_struct {
 443 +       __le32  mmp_magic;
 444 +       __le32  mmp_seq;
 445 +       __le64  mmp_time;
 446 +       char    mmp_nodename[64];
 447 +       char    mmp_bdevname[32];
 448 +       __le16  mmp_check_interval;
 449 +       __le16  mmp_pad1;
 450 +       __le32  mmp_pad2[227];
 451 +};
 452 +
 453 +/*
 454 + * Default interval in seconds to update the MMP sequence number.
 455 + */
 456 +#define EXT4_MMP_UPDATE_INTERVAL   1
 457 +
 458 +/*
 459 + * Minimum interval for MMP checking in seconds.
 460 + */
 461 +#define EXT4_MMP_MIN_CHECK_INTERVAL    5
 462 +
 463 +/*
 464   * Function prototypes
 465   */
 466
 467 Index: linux-2.6.18-128.1.6/fs/ext4/ext4_sb.h
 468 ===================================================================
 469 --- linux-2.6.18-128.1.6.orig/fs/ext4/ext4_sb.h
 470 +++ linux-2.6.18-128.1.6/fs/ext4/ext4_sb.h
 471 @@ -148,6 +148,8 @@ struct ext4_sb_info {
 472
 473         unsigned int s_log_groups_per_flex;
 474         struct flex_groups *s_flex_groups;
 475 +
 476 +       struct task_struct *s_mmp_tsk;  /* Kernel thread for multiple mount protection */
 477  };
 478
 479  #endif /* _EXT4_SB */