From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: [PATCH 7/9] vfs: Move waiting for inode writeback from end_writeback() to evict_inode() Date: Thu, 3 May 2012 14:48:01 +0200 Message-ID: <1336049283-5859-8-git-send-email-jack@suse.cz> References: <1336049283-5859-1-git-send-email-jack@suse.cz> Cc: LKML , Al Viro , Christoph Hellwig , dchinner@redhat.com, Wu Fengguang , Jan Kara To: linux-fsdevel@vger.kernel.org Return-path: In-Reply-To: <1336049283-5859-1-git-send-email-jack@suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org 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 --- fs/inode.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index 9f4f5fe..501fc5d 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 { -- 1.7.1