| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.18 80/84] Btrfs: make sure we wait on logged extents when fsycning two subvols | Date | Tue, 6 Jan 2015 17:50:23 -0800 |
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3.18-stable review patch. If anyone has any objections, please let me know.
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From: Josef Bacik <jbacik@fb.com>
commit 9dba8cf128ef98257ca719722280c9634e7e9dc7 upstream.
If we have two fsync()'s race on different subvols one will do all of its work to get into the log_tree, wait on it's outstanding IO, and then allow the log_tree to finish it's commit. The problem is we were just free'ing that subvols logged extents instead of waiting on them, so whoever lost the race wouldn't really have their data on disk. Fix this by waiting properly instead of freeing the logged extents. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/btrfs/tree-log.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -2600,9 +2600,9 @@ int btrfs_sync_log(struct btrfs_trans_ha if (atomic_read(&log_root_tree->log_commit[index2])) { blk_finish_plug(&plug); btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark); + btrfs_wait_logged_extents(log, log_transid); wait_log_commit(trans, log_root_tree, root_log_ctx.log_transid); - btrfs_free_logged_extents(log, log_transid); mutex_unlock(&log_root_tree->log_mutex); ret = root_log_ctx.log_ret; goto out;
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