From: Jan Kara Date: Fri, 13 Dec 2013 20:21:26 +0000 (+0800) Subject: writeback: Fix data corruption on NFS X-Git-Tag: firefly_0821_release~3679^2~3049 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=cc46cb337cf614b652b0068e6e388102bf8a9b54;p=firefly-linux-kernel-4.4.55.git writeback: Fix data corruption on NFS commit f9b0e058cbd04ada76b13afffa7e1df830543c24 upstream. Commit 4f8ad655dbc8 "writeback: Refactor writeback_single_inode()" added a condition to skip clean inode. However this is wrong in WB_SYNC_ALL mode because there we also want to wait for outstanding writeback on possibly clean inode. This was causing occasional data corruption issues on NFS because it uses sync_inode() to make sure all outstanding writes are flushed to the server before truncating the inode and with sync_inode() returning prematurely file was sometimes extended back by an outstanding write after it was truncated. So modify the test to also check for pages under writeback in WB_SYNC_ALL mode. Fixes: 4f8ad655dbc82cf05d2edc11e66b78a42d38bf93 Reported-and-tested-by: Dan Duval Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 3be57189efd5..e3ab1e4dc442 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -505,13 +505,16 @@ writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, } WARN_ON(inode->i_state & I_SYNC); /* - * Skip inode if it is clean. We don't want to mess with writeback - * lists in this function since flusher thread may be doing for example - * sync in parallel and if we move the inode, it could get skipped. So - * here we make sure inode is on some writeback list and leave it there - * unless we have completely cleaned the inode. + * Skip inode if it is clean and we have no outstanding writeback in + * WB_SYNC_ALL mode. We don't want to mess with writeback lists in this + * function since flusher thread may be doing for example sync in + * parallel and if we move the inode, it could get skipped. So here we + * make sure inode is on some writeback list and leave it there unless + * we have completely cleaned the inode. */ - if (!(inode->i_state & I_DIRTY)) + if (!(inode->i_state & I_DIRTY) && + (wbc->sync_mode != WB_SYNC_ALL || + !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))) goto out; inode->i_state |= I_SYNC; spin_unlock(&inode->i_lock);