From 22c963addcf426bef97a43f6e601f985f8082ed5 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 14 Apr 2009 05:34:24 +0200 Subject: [PATCH] kill-the-BKL/reiserfs: lock only once in reiserfs_truncate_file Impact: fix a deadlock reiserfs_truncate_file() can be called from multiple context where the write lock can be already hold or not. This function also acquire (possibly recursively) the write lock. Subsequent releases before sleeping will not actually release the lock because we may be in more than one lock depth degree. A typical case is: reiserfs_file_release { acquire_the_lock() reiserfs_truncate_file() reacquire_the_lock() journal_begin() { do_journal_begin_r() { reiserfs_wait_on_write_block() { /* * Not released because still one * depth owned */ release_lock() wait_for_event() At this stage the event never happen because the one which provides it needs the write lock. We use reiserfs_write_lock_once() here to ensure that we don't acquire the write lock recursively. Signed-off-by: Frederic Weisbecker Cc: Alessio Igor Bogani Cc: Jeff Mahoney Cc: Alexander Beregalov Cc: Chris Mason LKML-Reference: <1239680065-25013-3-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar --- fs/reiserfs/inode.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c index 1893c8198439..cc70b56bf6f2 100644 --- a/fs/reiserfs/inode.c +++ b/fs/reiserfs/inode.c @@ -2079,8 +2079,9 @@ int reiserfs_truncate_file(struct inode *inode, int update_timestamps) int error; struct buffer_head *bh = NULL; int err2; + int lock_depth; - reiserfs_write_lock(inode->i_sb); + lock_depth = reiserfs_write_lock_once(inode->i_sb); if (inode->i_size > 0) { error = grab_tail_page(inode, &page, &bh); @@ -2149,14 +2150,17 @@ int reiserfs_truncate_file(struct inode *inode, int update_timestamps) page_cache_release(page); } - reiserfs_write_unlock(inode->i_sb); + reiserfs_write_unlock_once(inode->i_sb, lock_depth); + return 0; out: if (page) { unlock_page(page); page_cache_release(page); } - reiserfs_write_unlock(inode->i_sb); + + reiserfs_write_unlock_once(inode->i_sb, lock_depth); + return error; }