Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (61 commits)
  jbd2: Add MAINTAINERS entry
  jbd2: fix a potential leak of a journal_head on an error path
  ext4: teach ext4_ext_split to calculate extents efficiently
  ext4: Convert ext4 to new truncate calling convention
  ext4: do not normalize block requests from fallocate()
  ext4: enable "punch hole" functionality
  ext4: add "punch hole" flag to ext4_map_blocks()
  ext4: punch out extents
  ext4: add new function ext4_block_zero_page_range()
  ext4: add flag to ext4_has_free_blocks
  ext4: reserve inodes and feature code for 'quota' feature
  ext4: add support for multiple mount protection
  ext4: ensure f_bfree returned by ext4_statfs() is non-negative
  ext4: protect bb_first_free in ext4_trim_all_free() with group lock
  ext4: only load buddy bitmap in ext4_trim_fs() when it is needed
  jbd2: Fix comment to match the code in jbd2__journal_start()
  ext4: fix waiting and sending of a barrier in ext4_sync_file()
  jbd2: Add function jbd2_trans_will_send_data_barrier()
  jbd2: fix sending of data flush on journal commit
  ext4: fix ext4_ext_fiemap_cb() to handle blocks before request range correctly
  ...

1 files changed, 351 insertions, 0 deletions

diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
new file mode 100644
index 000000000000..9bdef3f537c5
--- /dev/null
+++ b/fs/ext4/mmp.c
@@ -0,0 +1,351 @@
+#include <linux/fs.h>
+#include <linux/random.h>
+#include <linux/buffer_head.h>
+#include <linux/utsname.h>
+#include <linux/kthread.h>
+
+#include "ext4.h"
+
+/*
+ * Write the MMP block using WRITE_SYNC to try to get the block on-disk
+ * faster.
+ */
+static int write_mmp_block(struct buffer_head *bh)
+{
+        mark_buffer_dirty(bh);
+        lock_buffer(bh);
+        bh->b_end_io = end_buffer_write_sync;
+        get_bh(bh);
+        submit_bh(WRITE_SYNC, bh);
+        wait_on_buffer(bh);
+        if (unlikely(!buffer_uptodate(bh)))
+                return 1;
+
+        return 0;
+}
+
+/*
+ * Read the MMP block. It _must_ be read from disk and hence we clear the
+ * uptodate flag on the buffer.
+ */
+static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
+                          ext4_fsblk_t mmp_block)
+{
+        struct mmp_struct *mmp;
+
+        if (*bh)
+                clear_buffer_uptodate(*bh);
+
+        /* This would be sb_bread(sb, mmp_block), except we need to be sure
+         * that the MD RAID device cache has been bypassed, and that the read
+         * is not blocked in the elevator. */
+        if (!*bh)
+                *bh = sb_getblk(sb, mmp_block);
+        if (*bh) {
+                get_bh(*bh);
+                lock_buffer(*bh);
+                (*bh)->b_end_io = end_buffer_read_sync;
+                submit_bh(READ_SYNC, *bh);
+                wait_on_buffer(*bh);
+                if (!buffer_uptodate(*bh)) {
+                        brelse(*bh);
+                        *bh = NULL;
+                }
+        }
+        if (!*bh) {
+                ext4_warning(sb, "Error while reading MMP block %llu",
+                             mmp_block);
+                return -EIO;
+        }
+
+        mmp = (struct mmp_struct *)((*bh)->b_data);
+        if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC)
+                return -EINVAL;
+
+        return 0;
+}
+
+/*
+ * Dump as much information as possible to help the admin.
+ */
+void __dump_mmp_msg(struct super_block *sb, struct mmp_struct *mmp,
+                    const char *function, unsigned int line, const char *msg)
+{
+        __ext4_warning(sb, function, line, msg);
+        __ext4_warning(sb, function, line,
+                       "MMP failure info: last update time: %llu, last update "
+                       "node: %s, last update device: %s\n",
+                       (long long unsigned int) le64_to_cpu(mmp->mmp_time),
+                       mmp->mmp_nodename, mmp->mmp_bdevname);
+}
+
+/*
+ * kmmpd will update the MMP sequence every s_mmp_update_interval seconds
+ */
+static int kmmpd(void *data)
+{
+        struct super_block *sb = ((struct mmpd_data *) data)->sb;
+        struct buffer_head *bh = ((struct mmpd_data *) data)->bh;
+        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+        struct mmp_struct *mmp;
+        ext4_fsblk_t mmp_block;
+        u32 seq = 0;
+        unsigned long failed_writes = 0;
+        int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval);
+        unsigned mmp_check_interval;
+        unsigned long last_update_time;
+        unsigned long diff;
+        int retval;
+
+        mmp_block = le64_to_cpu(es->s_mmp_block);
+        mmp = (struct mmp_struct *)(bh->b_data);
+        mmp->mmp_time = cpu_to_le64(get_seconds());
+        /*
+         * Start with the higher mmp_check_interval and reduce it if
+         * the MMP block is being updated on time.
+         */
+        mmp_check_interval = max(EXT4_MMP_CHECK_MULT * mmp_update_interval,
+                                 EXT4_MMP_MIN_CHECK_INTERVAL);
+        mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
+        bdevname(bh->b_bdev, mmp->mmp_bdevname);
+
+        memcpy(mmp->mmp_nodename, init_utsname()->sysname,
+               sizeof(mmp->mmp_nodename));
+
+        while (!kthread_should_stop()) {
+                if (++seq > EXT4_MMP_SEQ_MAX)
+                        seq = 1;
+
+                mmp->mmp_seq = cpu_to_le32(seq);
+                mmp->mmp_time = cpu_to_le64(get_seconds());
+                last_update_time = jiffies;
+
+                retval = write_mmp_block(bh);
+                /*
+                 * Don't spew too many error messages. Print one every
+                 * (s_mmp_update_interval * 60) seconds.
+                 */
+                if (retval && (failed_writes % 60) == 0) {
+                        ext4_error(sb, "Error writing to MMP block");
+                        failed_writes++;
+                }
+
+                if (!(le32_to_cpu(es->s_feature_incompat) &
+                    EXT4_FEATURE_INCOMPAT_MMP)) {
+                        ext4_warning(sb, "kmmpd being stopped since MMP feature"
+                                     " has been disabled.");
+                        EXT4_SB(sb)->s_mmp_tsk = NULL;
+                        goto failed;
+                }
+
+                if (sb->s_flags & MS_RDONLY) {
+                        ext4_warning(sb, "kmmpd being stopped since filesystem "
+                                     "has been remounted as readonly.");
+                        EXT4_SB(sb)->s_mmp_tsk = NULL;
+                        goto failed;
+                }
+
+                diff = jiffies - last_update_time;
+                if (diff < mmp_update_interval * HZ)
+                        schedule_timeout_interruptible(mmp_update_interval *
+                                                       HZ - diff);
+
+                /*
+                 * We need to make sure that more than mmp_check_interval
+                 * seconds have not passed since writing. If that has happened
+                 * we need to check if the MMP block is as we left it.
+                 */
+                diff = jiffies - last_update_time;
+                if (diff > mmp_check_interval * HZ) {
+                        struct buffer_head *bh_check = NULL;
+                        struct mmp_struct *mmp_check;
+
+                        retval = read_mmp_block(sb, &bh_check, mmp_block);
+                        if (retval) {
+                                ext4_error(sb, "error reading MMP data: %d",
+                                           retval);
+
+                                EXT4_SB(sb)->s_mmp_tsk = NULL;
+                                goto failed;
+                        }
+
+                        mmp_check = (struct mmp_struct *)(bh_check->b_data);
+                        if (mmp->mmp_seq != mmp_check->mmp_seq ||
+                            memcmp(mmp->mmp_nodename, mmp_check->mmp_nodename,
+                                   sizeof(mmp->mmp_nodename))) {
+                                dump_mmp_msg(sb, mmp_check,
+                                             "Error while updating MMP info. "
+                                             "The filesystem seems to have been"
+                                             " multiply mounted.");
+                                ext4_error(sb, "abort");
+                                goto failed;
+                        }
+                        put_bh(bh_check);
+                }
+
+                 /*
+                 * Adjust the mmp_check_interval depending on how much time
+                 * it took for the MMP block to be written.
+                 */
+                mmp_check_interval = max(min(EXT4_MMP_CHECK_MULT * diff / HZ,
+                                             EXT4_MMP_MAX_CHECK_INTERVAL),
+                                         EXT4_MMP_MIN_CHECK_INTERVAL);
+                mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
+        }
+
+        /*
+         * Unmount seems to be clean.
+         */
+        mmp->mmp_seq = cpu_to_le32(EXT4_MMP_SEQ_CLEAN);
+        mmp->mmp_time = cpu_to_le64(get_seconds());
+
+        retval = write_mmp_block(bh);
+
+failed:
+        kfree(data);
+        brelse(bh);
+        return retval;
+}
+
+/*
+ * Get a random new sequence number but make sure it is not greater than
+ * EXT4_MMP_SEQ_MAX.
+ */
+static unsigned int mmp_new_seq(void)
+{
+        u32 new_seq;
+
+        do {
+                get_random_bytes(&new_seq, sizeof(u32));
+        } while (new_seq > EXT4_MMP_SEQ_MAX);
+
+        return new_seq;
+}
+
+/*
+ * Protect the filesystem from being mounted more than once.
+ */
+int ext4_multi_mount_protect(struct super_block *sb,
+                                    ext4_fsblk_t mmp_block)
+{
+        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+        struct buffer_head *bh = NULL;
+        struct mmp_struct *mmp = NULL;
+        struct mmpd_data *mmpd_data;
+        u32 seq;
+        unsigned int mmp_check_interval = le16_to_cpu(es->s_mmp_update_interval);
+        unsigned int wait_time = 0;
+        int retval;
+
+        if (mmp_block < le32_to_cpu(es->s_first_data_block) ||
+            mmp_block >= ext4_blocks_count(es)) {
+                ext4_warning(sb, "Invalid MMP block in superblock");
+                goto failed;
+        }
+
+        retval = read_mmp_block(sb, &bh, mmp_block);
+        if (retval)
+                goto failed;
+
+        mmp = (struct mmp_struct *)(bh->b_data);
+
+        if (mmp_check_interval < EXT4_MMP_MIN_CHECK_INTERVAL)
+                mmp_check_interval = EXT4_MMP_MIN_CHECK_INTERVAL;
+
+        /*
+         * If check_interval in MMP block is larger, use that instead of
+         * update_interval from the superblock.
+         */
+        if (mmp->mmp_check_interval > mmp_check_interval)
+                mmp_check_interval = mmp->mmp_check_interval;
+
+        seq = le32_to_cpu(mmp->mmp_seq);
+        if (seq == EXT4_MMP_SEQ_CLEAN)
+                goto skip;
+
+        if (seq == EXT4_MMP_SEQ_FSCK) {
+                dump_mmp_msg(sb, mmp, "fsck is running on the filesystem");
+                goto failed;
+        }
+
+        wait_time = min(mmp_check_interval * 2 + 1,
+                        mmp_check_interval + 60);
+
+        /* Print MMP interval if more than 20 secs. */
+        if (wait_time > EXT4_MMP_MIN_CHECK_INTERVAL * 4)
+                ext4_warning(sb, "MMP interval %u higher than expected, please"
+                             " wait.\n", wait_time * 2);
+
+        if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
+                ext4_warning(sb, "MMP startup interrupted, failing mount\n");
+                goto failed;
+        }
+
+        retval = read_mmp_block(sb, &bh, mmp_block);
+        if (retval)
+                goto failed;
+        mmp = (struct mmp_struct *)(bh->b_data);
+        if (seq != le32_to_cpu(mmp->mmp_seq)) {
+                dump_mmp_msg(sb, mmp,
+                             "Device is already active on another node.");
+                goto failed;
+        }
+
+skip:
+        /*
+         * write a new random sequence number.
+         */
+        mmp->mmp_seq = seq = cpu_to_le32(mmp_new_seq());
+
+        retval = write_mmp_block(bh);
+        if (retval)
+                goto failed;
+
+        /*
+         * wait for MMP interval and check mmp_seq.
+         */
+        if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
+                ext4_warning(sb, "MMP startup interrupted, failing mount\n");
+                goto failed;
+        }
+
+        retval = read_mmp_block(sb, &bh, mmp_block);
+        if (retval)
+                goto failed;
+        mmp = (struct mmp_struct *)(bh->b_data);
+        if (seq != le32_to_cpu(mmp->mmp_seq)) {
+                dump_mmp_msg(sb, mmp,
+                             "Device is already active on another node.");
+                goto failed;
+        }
+
+        mmpd_data = kmalloc(sizeof(struct mmpd_data), GFP_KERNEL);
+        if (!mmpd_data) {
+                ext4_warning(sb, "not enough memory for mmpd_data");
+                goto failed;
+        }
+        mmpd_data->sb = sb;
+        mmpd_data->bh = bh;
+
+        /*
+         * Start a kernel thread to update the MMP block periodically.
+         */
+        EXT4_SB(sb)->s_mmp_tsk = kthread_run(kmmpd, mmpd_data, "kmmpd-%s",
+                                             bdevname(bh->b_bdev,
+                                                      mmp->mmp_bdevname));
+        if (IS_ERR(EXT4_SB(sb)->s_mmp_tsk)) {
+                EXT4_SB(sb)->s_mmp_tsk = NULL;
+                kfree(mmpd_data);
+                ext4_warning(sb, "Unable to create kmmpd thread for %s.",
+                             sb->s_id);
+                goto failed;
+        }
+
+        return 0;
+
+failed:
+        brelse(bh);
+        return 1;
+}
+
+