From 7f27ec978b0ef37391262bbf15c587fd8526e268 Mon Sep 17 00:00:00 2001 From: yangwenfang Date: Fri, 4 Sep 2015 15:44:45 -0700 Subject: [PATCH] ocfs2: call ocfs2_journal_access_di() before ocfs2_journal_dirty() in ocfs2_write_end_nolock() 1: After we call ocfs2_journal_access_di() in ocfs2_write_begin(), jbd2_journal_restart() may also be called, in this function transaction A's t_updates-- and obtains a new transaction B. If jbd2_journal_commit_transaction() is happened to commit transaction A, when t_updates==0, it will continue to complete commit and unfile buffer. So when jbd2_journal_dirty_metadata(), the handle is pointed a new transaction B, and the buffer head's journal head is already freed, jh->b_transaction == NULL, jh->b_next_transaction == NULL, it returns EINVAL, So it triggers the BUG_ON(status). thread 1 jbd2 ocfs2_write_begin jbd2_journal_commit_transaction ocfs2_write_begin_nolock ocfs2_start_trans jbd2__journal_start(t_updates+1, transaction A) ocfs2_journal_access_di ocfs2_write_cluster_by_desc ocfs2_mark_extent_written ocfs2_change_extent_flag ocfs2_split_extent ocfs2_extend_rotate_transaction jbd2_journal_restart (t_updates-1,transaction B) t_updates==0 __jbd2_journal_refile_buffer (jh->b_transaction = NULL) ocfs2_write_end ocfs2_write_end_nolock ocfs2_journal_dirty jbd2_journal_dirty_metadata(bug) ocfs2_commit_trans 2. In ext4, I found that: jbd2_journal_get_write_access() called by ext4_write_end. ext4_write_begin ext4_journal_start __ext4_journal_start_sb ext4_journal_check_start jbd2__journal_start ext4_write_end ext4_mark_inode_dirty ext4_reserve_inode_write ext4_journal_get_write_access jbd2_journal_get_write_access ext4_mark_iloc_dirty ext4_do_update_inode ext4_handle_dirty_metadata jbd2_journal_dirty_metadata 3. So I think we should put ocfs2_journal_access_di before ocfs2_journal_dirty in the ocfs2_write_end. and it works well after my modification. Signed-off-by: vicky Reviewed-by: Mark Fasheh Cc: Joel Becker Cc: Zhangguanghui Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/aops.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index a7ab145e2901..faf36a96cd19 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -2207,10 +2207,7 @@ try_again: if (ret) goto out_commit; } - /* - * We don't want this to fail in ocfs2_write_end(), so do it - * here. - */ + ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh, OCFS2_JOURNAL_ACCESS_WRITE); if (ret) { @@ -2367,7 +2364,7 @@ int ocfs2_write_end_nolock(struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { - int i; + int i, ret; unsigned from, to, start = pos & (PAGE_CACHE_SIZE - 1); struct inode *inode = mapping->host; struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); @@ -2376,6 +2373,14 @@ int ocfs2_write_end_nolock(struct address_space *mapping, handle_t *handle = wc->w_handle; struct page *tmppage; + ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh, + OCFS2_JOURNAL_ACCESS_WRITE); + if (ret) { + copied = ret; + mlog_errno(ret); + goto out; + } + if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) { ocfs2_write_end_inline(inode, pos, len, &copied, di, wc); goto out_write_size; @@ -2431,6 +2436,7 @@ out_write_size: ocfs2_update_inode_fsync_trans(handle, inode, 1); ocfs2_journal_dirty(handle, wc->w_di_bh); +out: /* unlock pages before dealloc since it needs acquiring j_trans_barrier * lock, or it will cause a deadlock since journal commit threads holds * this lock and will ask for the page lock when flushing the data.