1 Index: linux-2.6.18-128.1.6/fs/ext3/super.c
2 ===================================================================
3 --- linux-2.6.18-128.1.6.orig/fs/ext3/super.c
4 +++ linux-2.6.18-128.1.6/fs/ext3/super.c
6 #include <linux/namei.h>
7 #include <linux/quotaops.h>
8 #include <linux/seq_file.h>
9 +#include <linux/kthread.h>
10 +#include <linux/utsname.h>
12 #include <asm/uaccess.h>
14 @@ -440,6 +442,8 @@ static void ext3_put_super (struct super
15 invalidate_bdev(sbi->journal_bdev, 0);
16 ext3_blkdev_remove(sbi);
19 + kthread_stop(sbi->s_mmp_tsk);
20 if (sbi->s_dev_proc) {
21 remove_proc_entry(sbi->s_dev_proc->name, proc_root_ext3);
22 sbi->s_dev_proc = NULL;
23 @@ -1548,6 +1552,329 @@ static ext3_fsblk_t descriptor_loc(struc
24 return (has_super + ext3_group_first_block_no(sb, bg));
28 + * Write the MMP block using WRITE_SYNC to try to get the block on-disk
31 +static int write_mmp_block(struct buffer_head *bh)
33 + mark_buffer_dirty(bh);
35 + bh->b_end_io = end_buffer_write_sync;
37 + submit_bh(WRITE_SYNC, bh);
39 + if (unlikely(!buffer_uptodate(bh)))
46 + * Read the MMP block. It _must_ be read from disk and hence we clear the
47 + * uptodate flag on the buffer.
49 +static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
50 + unsigned long mmp_block)
52 + struct mmp_struct *mmp;
55 + clear_buffer_uptodate(*bh);
60 + *bh = sb_bread(sb, mmp_block);
63 + *bh = sb_getblk(sb, mmp_block);
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)) {
77 + ext3_warning(sb, __FUNCTION__,
78 + "Error while reading MMP block %lu", mmp_block);
82 + mmp = (struct mmp_struct *)((*bh)->b_data);
83 + if (le32_to_cpu(mmp->mmp_magic) != EXT3_MMP_MAGIC)
90 + * Dump as much information as possible to help the admin.
92 +static void dump_mmp_msg(struct super_block *sb, struct mmp_struct *mmp,
93 + const char *function, const char *msg)
95 + ext3_warning(sb, function, msg);
96 + ext3_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,
103 + * kmmpd will update the MMP sequence every s_mmp_update_interval seconds
105 +static int kmmpd(void *data)
107 + struct super_block *sb = (struct super_block *) data;
108 + struct ext3_super_block *es = EXT3_SB(sb)->s_es;
109 + struct buffer_head *bh = NULL;
110 + struct mmp_struct *mmp;
111 + unsigned long mmp_block;
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;
120 + mmp_block = le64_to_cpu(es->s_mmp_block);
121 + retval = read_mmp_block(sb, &bh, mmp_block);
125 + mmp = (struct mmp_struct *)(bh->b_data);
126 + mmp->mmp_time = cpu_to_le64(get_seconds());
128 + * Start with the higher mmp_check_interval and reduce it if
129 + * the MMP block is being updated on time.
131 + mmp_check_interval = max(5 * mmp_update_interval,
132 + EXT3_MMP_MIN_CHECK_INTERVAL);
133 + mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
134 + bdevname(bh->b_bdev, mmp->mmp_bdevname);
136 + down_read(&uts_sem);
137 + memcpy(mmp->mmp_nodename, system_utsname.nodename,
138 + sizeof(mmp->mmp_nodename));
141 + while (!kthread_should_stop()) {
142 + if (++seq > EXT3_MMP_SEQ_MAX)
145 + mmp->mmp_seq = cpu_to_le32(seq);
146 + mmp->mmp_time = cpu_to_le64(get_seconds());
147 + last_update_time = jiffies;
149 + retval = write_mmp_block(bh);
151 + * Don't spew too many error messages. Print one every
152 + * (s_mmp_update_interval * 60) seconds.
154 + if (retval && (failed_writes % 60) == 0) {
155 + ext3_error(sb, __FUNCTION__,
156 + "Error writing to MMP block");
160 + if (!(le32_to_cpu(es->s_feature_incompat) &
161 + EXT3_FEATURE_INCOMPAT_MMP)) {
162 + ext3_warning(sb, __FUNCTION__, "kmmpd being stopped "
163 + "since MMP feature has been disabled.");
164 + EXT3_SB(sb)->s_mmp_tsk = 0;
168 + if (sb->s_flags & MS_RDONLY) {
169 + ext3_warning(sb, __FUNCTION__, "kmmpd being stopped "
170 + "since filesystem has been remounted as "
172 + EXT3_SB(sb)->s_mmp_tsk = 0;
176 + diff = jiffies - last_update_time;
177 + if (diff < mmp_update_interval * HZ)
178 + schedule_timeout_interruptible(EXT3_MMP_UPDATE_INTERVAL*
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.
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;
191 + retval = read_mmp_block(sb, &bh_check, mmp_block);
193 + EXT3_SB(sb)->s_mmp_tsk = 0;
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.");
210 + * Adjust the mmp_check_interval depending on how much time
211 + * it took for the MMP block to be written.
213 + mmp_check_interval = max(5 * diff / HZ,
214 + (unsigned long) EXT3_MMP_MIN_CHECK_INTERVAL);
215 + mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
219 + * Unmount seems to be clean.
221 + mmp->mmp_seq = cpu_to_le32(EXT3_MMP_SEQ_CLEAN);
222 + mmp->mmp_time = cpu_to_le64(get_seconds());
224 + retval = write_mmp_block(bh);
232 + * Get a random new sequence number but make sure it is not greater than
233 + * EXT3_MMP_SEQ_MAX.
235 +static unsigned int mmp_new_seq(void)
240 + get_random_bytes(&new_seq, sizeof(u32));
241 + } while (new_seq > EXT3_MMP_SEQ_MAX);
247 + * Protect the filesystem from being mounted more than once.
249 +static int ext3_multi_mount_protect(struct super_block *sb,
250 + unsigned long mmp_block)
252 + struct ext3_super_block *es = EXT3_SB(sb)->s_es;
253 + struct buffer_head *bh = NULL;
254 + struct mmp_struct *mmp = NULL;
256 + unsigned int mmp_check_interval = le16_to_cpu(es->s_mmp_update_interval);
259 + if (mmp_block < le32_to_cpu(es->s_first_data_block) ||
260 + mmp_block >= le32_to_cpu(es->s_blocks_count)) {
261 + ext3_warning(sb, __FUNCTION__,
262 + "Invalid MMP block in superblock");
266 + retval = read_mmp_block(sb, &bh, mmp_block);
270 + mmp = (struct mmp_struct *)(bh->b_data);
272 + if (mmp_check_interval < EXT3_MMP_MIN_CHECK_INTERVAL)
273 + mmp_check_interval = EXT3_MMP_MIN_CHECK_INTERVAL;
276 + * If check_interval in MMP block is larger, use that instead of
277 + * update_interval from the superblock.
279 + if (mmp->mmp_check_interval > mmp_check_interval)
280 + mmp_check_interval = mmp->mmp_check_interval;
282 + seq = le32_to_cpu(mmp->mmp_seq);
283 + if (seq == EXT3_MMP_SEQ_CLEAN)
286 + if (seq == EXT3_MMP_SEQ_FSCK) {
287 + dump_mmp_msg(sb, mmp, __FUNCTION__,
288 + "fsck is running on the filesystem");
292 + schedule_timeout_uninterruptible(HZ * (2 * mmp_check_interval + 1));
294 + retval = read_mmp_block(sb, &bh, mmp_block);
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.");
306 + * write a new random sequence number.
308 + mmp->mmp_seq = seq = cpu_to_le32(mmp_new_seq());
310 + retval = write_mmp_block(bh);
315 + * wait for MMP interval and check mmp_seq.
317 + schedule_timeout_uninterruptible(HZ * (2 * mmp_check_interval + 1));
319 + retval = read_mmp_block(sb, &bh, mmp_block);
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.");
330 + * Start a kernel thread to update the MMP block periodically.
332 + EXT3_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, sb, "kmmpd-%02x:%02x",
335 + if (IS_ERR(EXT3_SB(sb)->s_mmp_tsk)) {
336 + EXT3_SB(sb)->s_mmp_tsk = 0;
337 + ext3_warning(sb, __FUNCTION__, "Unable to create kmmpd thread "
338 + "for %s.", sb->s_id);
351 static int ext3_fill_super (struct super_block *sb, void *data, int silent)
353 @@ -1880,6 +2207,11 @@ static int ext3_fill_super (struct super
354 EXT3_HAS_INCOMPAT_FEATURE(sb,
355 EXT3_FEATURE_INCOMPAT_RECOVER));
357 + if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_MMP) &&
358 + !(sb->s_flags & MS_RDONLY))
359 + if (ext3_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
360 + goto failed_mount3;
363 * The first inode we look at is the journal inode. Don't try
364 * root first: it may be modified in the journal!
365 @@ -2012,6 +2344,8 @@ cantfind_ext3:
367 journal_destroy(sbi->s_journal);
369 + if (sbi->s_mmp_tsk)
370 + kthread_stop(sbi->s_mmp_tsk);
371 percpu_counter_destroy(&sbi->s_freeblocks_counter);
372 percpu_counter_destroy(&sbi->s_freeinodes_counter);
373 percpu_counter_destroy(&sbi->s_dirs_counter);
374 @@ -2497,7 +2831,7 @@ static int ext3_remount (struct super_bl
375 ext3_fsblk_t n_blocks_count = 0;
376 unsigned long old_sb_flags;
377 struct ext3_mount_options old_opts;
383 @@ -2595,6 +2929,13 @@ static int ext3_remount (struct super_bl
385 if (!ext3_setup_super (sb, es, 0))
386 sb->s_flags &= ~MS_RDONLY;
387 + if (EXT3_HAS_INCOMPAT_FEATURE(sb,
388 + EXT3_FEATURE_INCOMPAT_MMP))
389 + if (ext3_multi_mount_protect(sb,
390 + le64_to_cpu(es->s_mmp_block))) {
397 Index: linux-2.6.18-128.1.6/include/linux/ext3_fs.h
398 ===================================================================
399 --- linux-2.6.18-128.1.6.orig/include/linux/ext3_fs.h
400 +++ linux-2.6.18-128.1.6/include/linux/ext3_fs.h
401 @@ -594,13 +594,17 @@ struct ext3_super_block {
402 __le32 s_first_meta_bg; /* First metablock block group */
403 __le32 s_mkfs_time; /* When the filesystem was created */
404 __le32 s_jnl_blocks[17]; /* Backup of the journal inode */
405 - __le32 s_blocks_count_hi; /* Blocks count high 32 bits */
406 +/*150*/ __le32 s_blocks_count_hi; /* Blocks count high 32 bits */
407 __le32 s_r_blocks_count_hi; /* Reserved blocks count high 32 bits*/
408 __le32 s_free_blocks_count_hi; /* Free blocks count high 32 bits */
409 __le16 s_min_extra_isize; /* All inodes have at least # bytes */
410 __le16 s_want_extra_isize; /* New inodes should reserve # bytes */
411 - __le32 s_flags; /* Miscellaneous flags */
412 - __u32 s_reserved[167]; /* Padding to the end of the block */
413 +/*160*/ __le32 s_flags; /* Miscellaneous flags */
414 + __le16 s_raid_stride; /* RAID stride */
415 + __le16 s_mmp_update_interval; /* # seconds to wait in MMP checking */
416 + __le64 s_mmp_block; /* Block for multi-mount protection */
417 +/*170*/ __le32 s_raid_stripe_width; /* blocks on all data disks (N*stride)*/
418 + __le32 s_reserved[163]; /* Padding to the end of the block */
422 @@ -703,12 +707,14 @@ static inline int ext3_valid_inum(struct
423 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008 /* Journal device */
424 #define EXT3_FEATURE_INCOMPAT_META_BG 0x0010
425 #define EXT3_FEATURE_INCOMPAT_EXTENTS 0x0040 /* extents support */
426 +#define EXT3_FEATURE_INCOMPAT_MMP 0x0100
428 #define EXT3_FEATURE_COMPAT_SUPP EXT2_FEATURE_COMPAT_EXT_ATTR
429 #define EXT3_FEATURE_INCOMPAT_SUPP (EXT3_FEATURE_INCOMPAT_FILETYPE| \
430 EXT3_FEATURE_INCOMPAT_RECOVER| \
431 EXT3_FEATURE_INCOMPAT_META_BG| \
432 - EXT3_FEATURE_INCOMPAT_EXTENTS)
433 + EXT3_FEATURE_INCOMPAT_EXTENTS| \
434 + EXT3_FEATURE_INCOMPAT_MMP)
435 #define EXT3_FEATURE_RO_COMPAT_SUPP (EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER| \
436 EXT3_FEATURE_RO_COMPAT_LARGE_FILE| \
437 EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
438 @@ -871,6 +877,39 @@ ext3_group_first_block_no(struct super_b
439 #define ERR_BAD_DX_DIR -75000
442 + * This structure will be used for multiple mount protection. It will be
443 + * written into the block number saved in the s_mmp_block field in the
444 + * superblock. Programs that check MMP should assume that if
445 + * SEQ_FSCK (or any unknown code above SEQ_MAX) is present then it is NOT safe
446 + * to use the filesystem, regardless of how old the timestamp is.
448 +#define EXT3_MMP_MAGIC 0x004D4D50U /* ASCII for MMP */
449 +#define EXT3_MMP_SEQ_CLEAN 0xFF4D4D50U /* mmp_seq value for clean unmount */
450 +#define EXT3_MMP_SEQ_FSCK 0xE24D4D50U /* mmp_seq value when being fscked */
451 +#define EXT3_MMP_SEQ_MAX 0xE24D4D4FU /* maximum valid mmp_seq value */
457 + char mmp_nodename[64];
458 + char mmp_bdevname[32];
459 + __le16 mmp_check_interval;
461 + __le32 mmp_pad2[227];
465 + * Default interval in seconds to update the MMP sequence number.
467 +#define EXT3_MMP_UPDATE_INTERVAL 1
470 + * Minimum interval for MMP checking in seconds.
472 +#define EXT3_MMP_MIN_CHECK_INTERVAL 5
475 * Function prototypes
478 Index: linux-2.6.18-128.1.6/include/linux/ext3_fs_sb.h
479 ===================================================================
480 --- linux-2.6.18-128.1.6.orig/include/linux/ext3_fs_sb.h
481 +++ linux-2.6.18-128.1.6/include/linux/ext3_fs_sb.h
482 @@ -158,6 +158,7 @@ struct ext3_sb_info {
483 /* locality groups */
484 struct ext3_locality_group *s_locality_groups;
486 + struct task_struct *s_mmp_tsk; /* Kernel thread for multiple mount protection */
489 #define EXT3_GROUP_INFO(sb, group) \