From 7994e6f7254354e03028a11f98a27bd67dace9f1 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 3 May 2012 14:48:01 +0200 Subject: [PATCH] vfs: Move waiting for inode writeback from end_writeback() to evict_inode() Currently, I_SYNC can never be set when evict_inode() (and thus end_writeback()) is called because flusher thread holds inode reference while inode is under writeback. As a result inode_sync_wait() in those places currently does nothing. However that is going to change and unveils problems with calling inode_sync_wait() from end_writeback(). Several filesystems call end_writeback() after they have deleted the inode (btrfs, gfs2, ...) and other filesystems (ext3, ext4, reiserfs, ...) can deadlock when waiting for I_SYNC because they call end_writeback() from within a transaction. To avoid these issues, we move inode_sync_wait() into evict_inode() before calling ->evict_inode(). That way we preserve the current property that ->evict_inode() and writeback never run in parallel and all filesystems are safe. Signed-off-by: Jan Kara Signed-off-by: Fengguang Wu --- fs/inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/inode.c b/fs/inode.c index 9f4f5fecc096..501fc5daf6f4 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -500,7 +500,6 @@ void end_writeback(struct inode *inode) BUG_ON(!list_empty(&inode->i_data.private_list)); BUG_ON(!(inode->i_state & I_FREEING)); BUG_ON(inode->i_state & I_CLEAR); - inode_sync_wait(inode); /* don't need i_lock here, no concurrent mods to i_state */ inode->i_state = I_FREEING | I_CLEAR; } @@ -531,6 +530,8 @@ static void evict(struct inode *inode) inode_sb_list_del(inode); + inode_sync_wait(inode); + if (op->evict_inode) { op->evict_inode(inode); } else { -- 2.30.2