btrfs: add mount option to set commit interval

I'ts hardcoded to 30 seconds which is fine for most users. Higher values
defer data being synced to permanent storage with obvious consequences
when the system crashes. The upper bound is not forced, but a warning is
printed if it's more than 300 seconds (5 minutes).

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index c17acbce5bc342b7cbadb6e1a8d4b51f12247581..0632832d4446673c52fe549217a28f632a6ceb49 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1351,6 +1351,7 @@ struct btrfs_fs_info {
        u64 last_trans_log_full_commit;
        unsigned long mount_opt;
        unsigned long compress_type:4;
+       int commit_interval;
        /*
         * It is a suggestive number, the read side is safe even it gets a
         * wrong number because we will write out the data into a regular
@@ -1969,6 +1970,8 @@ struct btrfs_ioctl_defrag_range_args {
 #define BTRFS_MOUNT_CHECK_INTEGRITY_INCLUDING_EXTENT_DATA (1 << 21)
 #define BTRFS_MOUNT_PANIC_ON_FATAL_ERROR       (1 << 22)
 
+#define BTRFS_DEFAULT_COMMIT_INTERVAL  (30)
+
 #define btrfs_clear_opt(o, opt)                ((o) &= ~BTRFS_MOUNT_##opt)
 #define btrfs_set_opt(o, opt)          ((o) |= BTRFS_MOUNT_##opt)
 #define btrfs_raw_test_opt(o, opt)     ((o) & BTRFS_MOUNT_##opt)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 2a378abb03fb630a6a075689bd4e047ccf2d43ed..572e21eb644cff4616e57781e7d49f238aba249e 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1742,7 +1742,7 @@ static int transaction_kthread(void *arg)
 
        do {
                cannot_commit = false;
-               delay = HZ * 30;
+               delay = HZ * root->fs_info->commit_interval;
                mutex_lock(&root->fs_info->transaction_kthread_mutex);
 
                spin_lock(&root->fs_info->trans_lock);
@@ -1754,7 +1754,8 @@ static int transaction_kthread(void *arg)
 
                now = get_seconds();
                if (cur->state < TRANS_STATE_BLOCKED &&
-                   (now < cur->start_time || now - cur->start_time < 30)) {
+                   (now < cur->start_time ||
+                    now - cur->start_time < root->fs_info->commit_interval)) {
                        spin_unlock(&root->fs_info->trans_lock);
                        delay = HZ * 5;
                        goto sleep;
@@ -2194,6 +2195,7 @@ int open_ctree(struct super_block *sb,
        fs_info->defrag_inodes = RB_ROOT;
        fs_info->free_chunk_space = 0;
        fs_info->tree_mod_log = RB_ROOT;
+       fs_info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
 
        /* readahead state */
        INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 2cc5b80eeae9bee2e426dacb25d089dad3cfad9f..196790375bb3562b155db4a92e7b6f7b88691d6a 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -321,6 +321,7 @@ enum {
        Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
        Opt_check_integrity, Opt_check_integrity_including_extent_data,
        Opt_check_integrity_print_mask, Opt_fatal_errors,
+       Opt_commit_interval,
        Opt_err,
 };
 
@@ -361,6 +362,7 @@ static match_table_t tokens = {
        {Opt_check_integrity_including_extent_data, "check_int_data"},
        {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
        {Opt_fatal_errors, "fatal_errors=%s"},
+       {Opt_commit_interval, "commit=%d"},
        {Opt_err, NULL},
 };
 
@@ -645,6 +647,29 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                                goto out;
                        }
                        break;
+               case Opt_commit_interval:
+                       intarg = 0;
+                       ret = match_int(&args[0], &intarg);
+                       if (ret < 0) {
+                               printk(KERN_ERR
+                                       "btrfs: invalid commit interval\n");
+                               ret = -EINVAL;
+                               goto out;
+                       }
+                       if (intarg > 0) {
+                               if (intarg > 300) {
+                                       printk(KERN_WARNING
+                                           "btrfs: excessive commit interval %d\n",
+                                                       intarg);
+                               }
+                               info->commit_interval = intarg;
+                       } else {
+                               printk(KERN_INFO
+                                   "btrfs: using default commit interval %ds\n",
+                                   BTRFS_DEFAULT_COMMIT_INTERVAL);
+                               info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
+                       }
+                       break;
                case Opt_err:
                        printk(KERN_INFO "btrfs: unrecognized mount option "
                               "'%s'\n", p);
@@ -981,6 +1006,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
                                info->metadata_ratio);
        if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
                seq_puts(seq, ",fatal_errors=panic");
+       if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
+               seq_printf(seq, ",commit=%d", info->commit_interval);
        return 0;
 }