Commit dccae999 authored by Sage Weil's avatar Sage Weil Committed by Chris Mason
Browse files

Btrfs: add flushoncommit mount option 



The 'flushoncommit' mount option forces any data dirtied by a write in a
prior transaction to commit as part of the current commit.  This makes
the committed state a fully consistent view of the file system from the
application's perspective (i.e., it includes all completed file system
operations).  This was previously the behavior only when a snapshot is
created.

This is used by Ceph to ensure that completed writes make it to the
platter along with the metadata operations they are bound to (by
BTRFS_IOC_TRANS_{START,END}).

Signed-off-by: default avatarSage Weil <sage@newdream.net>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 3a5e1404

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -1037,6 +1037,7 @@ struct btrfs_root { 
#define BTRFS_MOUNT_DEGRADED		(1 << 4)

#define BTRFS_MOUNT_COMPRESS		(1 << 5)

#define BTRFS_MOUNT_NOTREELOG           (1 << 6)

#define BTRFS_MOUNT_FLUSHONCOMMIT       (1 << 7)



#define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)

#define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)

fs/btrfs/super.c

+10 −4
Original line number Diff line number Diff line
@@ -68,7 +68,7 @@ enum { 
	Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,

	Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,

	Opt_ssd, Opt_thread_pool, Opt_noacl,  Opt_compress, Opt_notreelog,

	Opt_err,

	Opt_flushoncommit, Opt_err,

};



static match_table_t tokens = {
@@ -86,6 +86,7 @@ static match_table_t tokens = { 
	{Opt_ssd, "ssd"},

	{Opt_noacl, "noacl"},

	{Opt_notreelog, "notreelog"},

	{Opt_flushoncommit, "flushoncommit"},

	{Opt_err, NULL},

};
@@ -229,6 +230,10 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) 
			printk(KERN_INFO "btrfs: disabling tree log\n");

			btrfs_set_opt(info->mount_opt, NOTREELOG);

			break;

		case Opt_flushoncommit:

			printk(KERN_INFO "btrfs: turning on flush-on-commit\n");

			btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);

			break;

		default:

			break;

		}
@@ -370,9 +375,8 @@ fail_close: 
int btrfs_sync_fs(struct super_block *sb, int wait)

{

	struct btrfs_trans_handle *trans;

	struct btrfs_root *root;

	struct btrfs_root *root = btrfs_sb(sb);

	int ret;

	root = btrfs_sb(sb);



	if (sb->s_flags & MS_RDONLY)

		return 0;
@@ -419,7 +423,9 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs) 
	if (btrfs_test_opt(root, SSD))

		seq_puts(seq, ",ssd");

	if (btrfs_test_opt(root, NOTREELOG))

		seq_puts(seq, ",notreelog");

		seq_puts(seq, ",no-treelog");

	if (btrfs_test_opt(root, FLUSHONCOMMIT))

		seq_puts(seq, ",flush-on-commit");

	if (!(root->fs_info->sb->s_flags & MS_POSIXACL))

		seq_puts(seq, ",noacl");

	return 0;

fs/btrfs/transaction.c

+4 −1
Original line number Diff line number Diff line
@@ -972,6 +972,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
	int ret;

	int should_grow = 0;

	unsigned long now = get_seconds();

	int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);



	btrfs_run_ordered_operations(root, 0);
@@ -1051,7 +1052,9 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 


		mutex_unlock(&root->fs_info->trans_mutex);



		if (snap_pending) {

		if (flush_on_commit || snap_pending) {

			if (flush_on_commit)

				btrfs_start_delalloc_inodes(root);

			ret = btrfs_wait_ordered_extents(root, 1);

			BUG_ON(ret);

		}

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