From 1a387d3be2b30c90f20d49a3497a8fc0693a9d18 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Tue, 24 Aug 2010 11:46:31 +1000 Subject: xfs: dummy transactions should not dirty VFS state When we need to cover the log, we issue dummy transactions to ensure the current log tail is on disk. Unfortunately we currently use the root inode in the dummy transaction, and the act of committing the transaction dirties the inode at the VFS level. As a result, the VFS writeback of the dirty inode will prevent the filesystem from idling long enough for the log covering state machine to complete. The state machine gets stuck in a loop issuing new dummy transactions to cover the log and never makes progress. To avoid this problem, the dummy transactions should not cause externally visible state changes. To ensure this occurs, make sure that dummy transactions log an unchanging field in the superblock as it's state is never propagated outside the filesystem. This allows the log covering state machine to complete successfully and the filesystem now correctly enters a fully idle state about 90s after the last modification was made. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig --- fs/xfs/linux-2.6/xfs_super.c | 2 +- fs/xfs/linux-2.6/xfs_sync.c | 42 ++++++------------------------------------ 2 files changed, 7 insertions(+), 37 deletions(-) (limited to 'fs/xfs/linux-2.6') diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c index c6b24e7..a4e0797 100644 --- a/fs/xfs/linux-2.6/xfs_super.c +++ b/fs/xfs/linux-2.6/xfs_super.c @@ -1407,7 +1407,7 @@ xfs_fs_freeze( xfs_save_resvblks(mp); xfs_quiesce_attr(mp); - return -xfs_fs_log_dummy(mp); + return -xfs_fs_log_dummy(mp, SYNC_WAIT); } STATIC int diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c index dfcbd98..d59c4a6 100644 --- a/fs/xfs/linux-2.6/xfs_sync.c +++ b/fs/xfs/linux-2.6/xfs_sync.c @@ -34,6 +34,7 @@ #include "xfs_inode_item.h" #include "xfs_quota.h" #include "xfs_trace.h" +#include "xfs_fsops.h" #include #include @@ -341,38 +342,6 @@ xfs_sync_attr( } STATIC int -xfs_commit_dummy_trans( - struct xfs_mount *mp, - uint flags) -{ - struct xfs_inode *ip = mp->m_rootip; - struct xfs_trans *tp; - int error; - - /* - * Put a dummy transaction in the log to tell recovery - * that all others are OK. - */ - tp = xfs_trans_alloc(mp, XFS_TRANS_DUMMY1); - error = xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp), 0, 0, 0); - if (error) { - xfs_trans_cancel(tp, 0); - return error; - } - - xfs_ilock(ip, XFS_ILOCK_EXCL); - - xfs_trans_ijoin(tp, ip); - xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); - error = xfs_trans_commit(tp, 0); - xfs_iunlock(ip, XFS_ILOCK_EXCL); - - /* the log force ensures this transaction is pushed to disk */ - xfs_log_force(mp, (flags & SYNC_WAIT) ? XFS_LOG_SYNC : 0); - return error; -} - -STATIC int xfs_sync_fsdata( struct xfs_mount *mp) { @@ -432,7 +401,7 @@ xfs_quiesce_data( /* mark the log as covered if needed */ if (xfs_log_need_covered(mp)) - error2 = xfs_commit_dummy_trans(mp, SYNC_WAIT); + error2 = xfs_fs_log_dummy(mp, SYNC_WAIT); /* flush data-only devices */ if (mp->m_rtdev_targp) @@ -563,7 +532,7 @@ xfs_flush_inodes( /* * Every sync period we need to unpin all items, reclaim inodes and sync * disk quotas. We might need to cover the log to indicate that the - * filesystem is idle. + * filesystem is idle and not frozen. */ STATIC void xfs_sync_worker( @@ -577,8 +546,9 @@ xfs_sync_worker( xfs_reclaim_inodes(mp, 0); /* dgc: errors ignored here */ error = xfs_qm_sync(mp, SYNC_TRYLOCK); - if (xfs_log_need_covered(mp)) - error = xfs_commit_dummy_trans(mp, 0); + if (mp->m_super->s_frozen == SB_UNFROZEN && + xfs_log_need_covered(mp)) + error = xfs_fs_log_dummy(mp, 0); } mp->m_sync_seq++; wake_up(&mp->m_wait_single_sync_task); -- cgit v1.1