ldiskfs/kernel_patches/patches/ext4-mmp-sles11.patch

   1 Index: linux-2.6.27.21-0.1/fs/ext4/super.c
   2 ===================================================================
   3 --- linux-2.6.27.21-0.1.orig/fs/ext4/super.c    2009-07-07 14:36:58.000000000 +0530
   4 +++ linux-2.6.27.21-0.1/fs/ext4/super.c 2009-07-07 14:38:06.000000000 +0530
   5 @@ -39,6 +39,8 @@
   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 @@ -599,6 +601,8 @@
  15                 invalidate_bdev(sbi->journal_bdev);
  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 @@ -807,7 +811,6 @@
  24         if (!test_opt(sb, DELALLOC))
  25                 seq_puts(seq, ",nodelalloc");
  26
  27 -
  28         if (sbi->s_stripe)
  29                 seq_printf(seq, ",stripe=%lu", sbi->s_stripe);
  30         /*
  31 @@ -830,6 +833,325 @@
  32  }
  33
  34
  35 +
  36 +/*
  37 + * Write the MMP block using WRITE_SYNC to try to get the block on-disk
  38 + * faster.
  39 + */
  40 +static int write_mmp_block(struct buffer_head *bh)
  41 +{
  42 +       mark_buffer_dirty(bh);
  43 +       lock_buffer(bh);
  44 +       bh->b_end_io = end_buffer_write_sync;
  45 +       get_bh(bh);
  46 +       submit_bh(WRITE_SYNC, bh);
  47 +       wait_on_buffer(bh);
  48 +       if (unlikely(!buffer_uptodate(bh)))
  49 +               return 1;
  50 +
  51 +       return 0;
  52 +}
  53 +
  54 +/*
  55 + * Read the MMP block. It _must_ be read from disk and hence we clear the
  56 + * uptodate flag on the buffer.
  57 + */
  58 +static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
  59 +                         unsigned long mmp_block)
  60 +{
  61 +       struct mmp_struct *mmp;
  62 +
  63 +       if (*bh)
  64 +               clear_buffer_uptodate(*bh);
  65 +
  66 +       /* This would be sb_bread(sb, mmp_block), except we need to be sure
  67 +        * that the MD RAID device cache has been bypassed, and that the read
  68 +        * is not blocked in the elevator. */
  69 +       if (!*bh)
  70 +               *bh = sb_getblk(sb, mmp_block);
  71 +       if (*bh) {
  72 +               get_bh(*bh);
  73 +               lock_buffer(*bh);
  74 +               (*bh)->b_end_io = end_buffer_read_sync;
  75 +               submit_bh(READ_SYNC, *bh);
  76 +               wait_on_buffer(*bh);
  77 +               if (!buffer_uptodate(*bh)) {
  78 +                       brelse(*bh);
  79 +                       *bh = NULL;
  80 +               }
  81 +       }
  82 +       if (!*bh) {
  83 +               ext4_warning(sb, __FUNCTION__,
  84 +                            "Error while reading MMP block %lu", mmp_block);
  85 +               return -EIO;
  86 +       }
  87 +
  88 +       mmp = (struct mmp_struct *)((*bh)->b_data);
  89 +       if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC)
  90 +               return -EINVAL;
  91 +
  92 +       return 0;
  93 +}
  94 +
  95 +/*
  96 + * Dump as much information as possible to help the admin.
  97 + */
  98 +static void dump_mmp_msg(struct super_block *sb, struct mmp_struct *mmp,
  99 +                        const char *function, const char *msg)
 100 +{
 101 +       ext4_warning(sb, function, msg);
 102 +       ext4_warning(sb, function, "MMP failure info: last update time: %llu, "
 103 +                    "last update node: %s, last update device: %s\n",
 104 +                    le64_to_cpu(mmp->mmp_time), mmp->mmp_nodename,
 105 +                    mmp->mmp_bdevname);
 106 +}
 107 +
 108 +/*
 109 + * kmmpd will update the MMP sequence every s_mmp_update_interval seconds
 110 + */
 111 +static int kmmpd(void *data)
 112 +{
 113 +       struct super_block *sb = (struct super_block *) data;
 114 +       struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 115 +       struct buffer_head *bh = NULL;
 116 +       struct mmp_struct *mmp;
 117 +       unsigned long mmp_block;
 118 +       u32 seq = 0;
 119 +       unsigned long failed_writes = 0;
 120 +       int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval);
 121 +       unsigned mmp_check_interval;
 122 +       unsigned long last_update_time;
 123 +       unsigned long diff;
 124 +       int retval;
 125 +
 126 +       mmp_block = le64_to_cpu(es->s_mmp_block);
 127 +       retval = read_mmp_block(sb, &bh, mmp_block);
 128 +       if (retval)
 129 +               goto failed;
 130 +
 131 +       mmp = (struct mmp_struct *)(bh->b_data);
 132 +       mmp->mmp_time = cpu_to_le64(get_seconds());
 133 +       /*
 134 +        * Start with the higher mmp_check_interval and reduce it if
 135 +        * the MMP block is being updated on time.
 136 +        */
 137 +       mmp_check_interval = max(5 * mmp_update_interval,
 138 +                                EXT4_MMP_MIN_CHECK_INTERVAL);
 139 +       mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
 140 +       bdevname(bh->b_bdev, mmp->mmp_bdevname);
 141 +
 142 +       memcpy(mmp->mmp_nodename, init_utsname()->sysname,
 143 +              sizeof(mmp->mmp_nodename));
 144 +
 145 +       while (!kthread_should_stop()) {
 146 +               if (++seq > EXT4_MMP_SEQ_MAX)
 147 +                       seq = 1;
 148 +
 149 +               mmp->mmp_seq = cpu_to_le32(seq);
 150 +               mmp->mmp_time = cpu_to_le64(get_seconds());
 151 +               last_update_time = jiffies;
 152 +
 153 +               retval = write_mmp_block(bh);
 154 +               /*
 155 +                * Don't spew too many error messages. Print one every
 156 +                * (s_mmp_update_interval * 60) seconds.
 157 +                */
 158 +               if (retval && (failed_writes % 60) == 0) {
 159 +                       ext4_error(sb, __FUNCTION__,
 160 +                                  "Error writing to MMP block");
 161 +                       failed_writes++;
 162 +               }
 163 +
 164 +               if (!(le32_to_cpu(es->s_feature_incompat) &
 165 +                   EXT4_FEATURE_INCOMPAT_MMP)) {
 166 +                       ext4_warning(sb, __FUNCTION__, "kmmpd being stopped "
 167 +                                    "since MMP feature has been disabled.");
 168 +                       EXT4_SB(sb)->s_mmp_tsk = 0;
 169 +                       goto failed;
 170 +               }
 171 +
 172 +               if (sb->s_flags & MS_RDONLY) {
 173 +                       ext4_warning(sb, __FUNCTION__, "kmmpd being stopped "
 174 +                                    "since filesystem has been remounted as "
 175 +                                    "readonly.");
 176 +                       EXT4_SB(sb)->s_mmp_tsk = 0;
 177 +                       goto failed;
 178 +               }
 179 +
 180 +               diff = jiffies - last_update_time;
 181 +               if (diff < mmp_update_interval * HZ)
 182 +                       schedule_timeout_interruptible(EXT4_MMP_UPDATE_INTERVAL*
 183 +                                                      HZ - diff);
 184 +
 185 +               /*
 186 +                * We need to make sure that more than mmp_check_interval
 187 +                * seconds have not passed since writing. If that has happened
 188 +                * we need to check if the MMP block is as we left it.
 189 +                */
 190 +               diff = jiffies - last_update_time;
 191 +               if (diff > mmp_check_interval * HZ) {
 192 +                       struct buffer_head *bh_check = NULL;
 193 +                       struct mmp_struct *mmp_check;
 194 +
 195 +                       retval = read_mmp_block(sb, &bh_check, mmp_block);
 196 +                       if (retval) {
 197 +                               EXT4_SB(sb)->s_mmp_tsk = 0;
 198 +                               goto failed;
 199 +                       }
 200 +
 201 +                       mmp_check = (struct mmp_struct *)(bh_check->b_data);
 202 +                       if (mmp->mmp_time != mmp_check->mmp_time ||
 203 +                           memcmp(mmp->mmp_nodename, mmp_check->mmp_nodename,
 204 +                                  sizeof(mmp->mmp_nodename)))
 205 +                               dump_mmp_msg(sb, mmp_check, __FUNCTION__,
 206 +                                            "Error while updating MMP info. "
 207 +                                            "The filesystem seems to have "
 208 +                                            "been multiply mounted.");
 209 +
 210 +                       put_bh(bh_check);
 211 +               }
 212 +
 213 +               /*
 214 +                * Adjust the mmp_check_interval depending on how much time
 215 +                * it took for the MMP block to be written.
 216 +                */
 217 +               mmp_check_interval = max(5 * diff / HZ,
 218 +                                (unsigned long) EXT4_MMP_MIN_CHECK_INTERVAL);
 219 +               mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
 220 +       }
 221 +
 222 +       /*
 223 +        * Unmount seems to be clean.
 224 +        */
 225 +       mmp->mmp_seq = cpu_to_le32(EXT4_MMP_SEQ_CLEAN);
 226 +       mmp->mmp_time = cpu_to_le64(get_seconds());
 227 +
 228 +       retval = write_mmp_block(bh);
 229 +
 230 +failed:
 231 +       brelse(bh);
 232 +       return retval;
 233 +}
 234 +
 235 +/*
 236 + * Get a random new sequence number but make sure it is not greater than
 237 + * EXT4_MMP_SEQ_MAX.
 238 + */
 239 +static unsigned int mmp_new_seq(void)
 240 +{
 241 +       u32 new_seq;
 242 +
 243 +       do {
 244 +               get_random_bytes(&new_seq, sizeof(u32));
 245 +       } while (new_seq > EXT4_MMP_SEQ_MAX);
 246 +
 247 +       return new_seq;
 248 +}
 249 +
 250 +/*
 251 + * Protect the filesystem from being mounted more than once.
 252 + */
 253 +static int ext4_multi_mount_protect(struct super_block *sb,
 254 +                                   unsigned long mmp_block)
 255 +{
 256 +       struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 257 +       struct buffer_head *bh = NULL;
 258 +       struct mmp_struct *mmp = NULL;
 259 +       u32 seq;
 260 +       unsigned int mmp_check_interval = le16_to_cpu(es->s_mmp_update_interval);
 261 +       int retval;
 262 +
 263 +       if (mmp_block < le32_to_cpu(es->s_first_data_block) ||
 264 +           mmp_block >= ext4_blocks_count(es)) {
 265 +               ext4_warning(sb, __FUNCTION__,
 266 +                            "Invalid MMP block in superblock");
 267 +               goto failed;
 268 +       }
 269 +
 270 +       retval = read_mmp_block(sb, &bh, mmp_block);
 271 +       if (retval)
 272 +               goto failed;
 273 +
 274 +       mmp = (struct mmp_struct *)(bh->b_data);
 275 +
 276 +       if (mmp_check_interval < EXT4_MMP_MIN_CHECK_INTERVAL)
 277 +               mmp_check_interval = EXT4_MMP_MIN_CHECK_INTERVAL;
 278 +
 279 +       /*
 280 +        * If check_interval in MMP block is larger, use that instead of
 281 +        * update_interval from the superblock.
 282 +        */
 283 +       if (mmp->mmp_check_interval > mmp_check_interval)
 284 +               mmp_check_interval = mmp->mmp_check_interval;
 285 +
 286 +       seq = le32_to_cpu(mmp->mmp_seq);
 287 +       if (seq == EXT4_MMP_SEQ_CLEAN)
 288 +               goto skip;
 289 +
 290 +       if (seq == EXT4_MMP_SEQ_FSCK) {
 291 +               dump_mmp_msg(sb, mmp, __FUNCTION__,
 292 +                            "fsck is running on the filesystem");
 293 +               goto failed;
 294 +       }
 295 +
 296 +       schedule_timeout_uninterruptible(HZ * (2 * mmp_check_interval + 1));
 297 +
 298 +       retval = read_mmp_block(sb, &bh, mmp_block);
 299 +       if (retval)
 300 +               goto failed;
 301 +       mmp = (struct mmp_struct *)(bh->b_data);
 302 +       if (seq != le32_to_cpu(mmp->mmp_seq)) {
 303 +               dump_mmp_msg(sb, mmp, __FUNCTION__,
 304 +                            "Device is already active on another node.");
 305 +               goto failed;
 306 +       }
 307 +
 308 +skip:
 309 +       /*
 310 +        * write a new random sequence number.
 311 +        */
 312 +       mmp->mmp_seq = seq = cpu_to_le32(mmp_new_seq());
 313 +
 314 +       retval = write_mmp_block(bh);
 315 +       if (retval)
 316 +               goto failed;
 317 +
 318 +       /*
 319 +        * wait for MMP interval and check mmp_seq.
 320 +        */
 321 +       schedule_timeout_uninterruptible(HZ * (2 * mmp_check_interval + 1));
 322 +
 323 +       retval = read_mmp_block(sb, &bh, mmp_block);
 324 +       if (retval)
 325 +               goto failed;
 326 +       mmp = (struct mmp_struct *)(bh->b_data);
 327 +       if (seq != le32_to_cpu(mmp->mmp_seq)) {
 328 +               dump_mmp_msg(sb, mmp, __FUNCTION__,
 329 +                            "Device is already active on another node.");
 330 +               goto failed;
 331 +       }
 332 +
 333 +       /*
 334 +        * Start a kernel thread to update the MMP block periodically.
 335 +        */
 336 +       EXT4_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, sb, "kmmpd-%02x:%02x",
 337 +                                            MAJOR(sb->s_dev),
 338 +                                            MINOR(sb->s_dev));
 339 +       if (IS_ERR(EXT4_SB(sb)->s_mmp_tsk)) {
 340 +               EXT4_SB(sb)->s_mmp_tsk = 0;
 341 +               ext4_warning(sb, __FUNCTION__, "Unable to create kmmpd thread "
 342 +                            "for %s.", sb->s_id);
 343 +               goto failed;
 344 +       }
 345 +
 346 +       brelse(bh);
 347 +       return 0;
 348 +
 349 +failed:
 350 +       brelse(bh);
 351 +       return 1;
 352 +}
 353 +
 354  static struct inode *ext4_nfs_get_inode(struct super_block *sb,
 355                 u64 ino, u32 generation)
 356  {
 357 @@ -2370,6 +2692,11 @@
 358                           EXT4_HAS_INCOMPAT_FEATURE(sb,
 359                                     EXT4_FEATURE_INCOMPAT_RECOVER));
 360
 361 +       if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_MMP) &&
 362 +           !(sb->s_flags & MS_RDONLY))
 363 +               if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
 364 +                       goto failed_mount3;
 365 +
 366         /*
 367          * The first inode we look at is the journal inode.  Don't try
 368          * root first: it may be modified in the journal!
 369 @@ -2570,6 +2897,8 @@
 370         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 371         percpu_counter_destroy(&sbi->s_dirs_counter);
 372         percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
 373 +       if (sbi->s_mmp_tsk)
 374 +               kthread_stop(sbi->s_mmp_tsk);
 375  failed_mount2:
 376         for (i = 0; i < db_count; i++)
 377                 brelse(sbi->s_group_desc[i]);
 378 @@ -3085,7 +3414,7 @@
 379         unsigned long old_sb_flags;
 380         struct ext4_mount_options old_opts;
 381         ext4_group_t g;
 382 -       int err;
 383 +       int err = 0;
 384  #ifdef CONFIG_QUOTA
 385         int i;
 386  #endif
 387 @@ -3210,6 +3539,13 @@
 388                                 goto restore_opts;
 389                         if (!ext4_setup_super(sb, es, 0))
 390                                 sb->s_flags &= ~MS_RDONLY;
 391 +                       if (EXT4_HAS_INCOMPAT_FEATURE(sb,
 392 +                                                   EXT4_FEATURE_INCOMPAT_MMP))
 393 +                               if (ext4_multi_mount_protect(sb,
 394 +                                               le64_to_cpu(es->s_mmp_block))) {
 395 +                                       err = -EROFS;
 396 +                                       goto restore_opts;
 397 +                               }
 398                 }
 399         }
 400  #ifdef CONFIG_QUOTA
 401 Index: linux-2.6.27.21-0.1/fs/ext4/ext4.h
 402 ===================================================================
 403 --- linux-2.6.27.21-0.1.orig/fs/ext4/ext4.h     2009-07-07 14:36:00.000000000 +0530
 404 +++ linux-2.6.27.21-0.1/fs/ext4/ext4.h  2009-07-07 14:36:58.000000000 +0530
 405 @@ -660,7 +660,7 @@
 406         __le16  s_want_extra_isize;     /* New inodes should reserve # bytes */
 407         __le32  s_flags;                /* Miscellaneous flags */
 408         __le16  s_raid_stride;          /* RAID stride */
 409 -       __le16  s_mmp_interval;         /* # seconds to wait in MMP checking */
 410 +       __le16  s_mmp_update_interval;  /* # seconds to wait in MMP checking */
 411         __le64  s_mmp_block;            /* Block for multi-mount protection */
 412         __le32  s_raid_stripe_width;    /* blocks on all data disks (N*stride)*/
 413         __u8    s_log_groups_per_flex;  /* FLEX_BG group size */
 414 @@ -777,7 +777,8 @@
 415                                          EXT4_FEATURE_INCOMPAT_META_BG| \
 416                                          EXT4_FEATURE_INCOMPAT_EXTENTS| \
 417                                          EXT4_FEATURE_INCOMPAT_64BIT| \
 418 -                                        EXT4_FEATURE_INCOMPAT_FLEX_BG)
 419 +                                        EXT4_FEATURE_INCOMPAT_FLEX_BG| \
 420 +                                        EXT4_FEATURE_INCOMPAT_MMP)
 421  #define EXT4_FEATURE_RO_COMPAT_SUPP    (EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 422                                          EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
 423                                          EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
 424 @@ -981,6 +982,39 @@
 425  #endif
 426
 427  /*
 428 + * This structure will be used for multiple mount protection. It will be
 429 + * written into the block number saved in the s_mmp_block field in the
 430 + * superblock. Programs that check MMP should assume that if
 431 + * SEQ_FSCK (or any unknown code above SEQ_MAX) is present then it is NOT safe
 432 + * to use the filesystem, regardless of how old the timestamp is.
 433 + */
 434 +#define EXT4_MMP_MAGIC     0x004D4D50U /* ASCII for MMP */
 435 +#define EXT4_MMP_SEQ_CLEAN 0xFF4D4D50U /* mmp_seq value for clean unmount */
 436 +#define EXT4_MMP_SEQ_FSCK  0xE24D4D50U /* mmp_seq value when being fscked */
 437 +#define EXT4_MMP_SEQ_MAX   0xE24D4D4FU /* maximum valid mmp_seq value */
 438 +
 439 +struct mmp_struct {
 440 +       __le32  mmp_magic;
 441 +       __le32  mmp_seq;
 442 +       __le64  mmp_time;
 443 +       char    mmp_nodename[64];
 444 +       char    mmp_bdevname[32];
 445 +       __le16  mmp_check_interval;
 446 +       __le16  mmp_pad1;
 447 +       __le32  mmp_pad2[227];
 448 +};
 449 +
 450 +/*
 451 + * Default interval in seconds to update the MMP sequence number.
 452 + */
 453 +#define EXT4_MMP_UPDATE_INTERVAL   1
 454 +
 455 +/*
 456 + * Minimum interval for MMP checking in seconds.
 457 + */
 458 +#define EXT4_MMP_MIN_CHECK_INTERVAL    5
 459 +
 460 +/*
 461   * Function prototypes
 462   */
 463
 464 Index: linux-2.6.27.21-0.1/fs/ext4/ext4_sb.h
 465 ===================================================================
 466 --- linux-2.6.27.21-0.1.orig/fs/ext4/ext4_sb.h  2009-07-07 14:36:00.000000000 +0530
 467 +++ linux-2.6.27.21-0.1/fs/ext4/ext4_sb.h       2009-07-07 14:36:58.000000000 +0530
 468 @@ -149,6 +149,8 @@
 469
 470         unsigned int s_log_groups_per_flex;
 471         struct flex_groups *s_flex_groups;
 472 +
 473 +       struct task_struct *s_mmp_tsk;  /* Kernel thread for multiple mount protection */
 474  };
 475
 476  #endif /* _EXT4_SB */