From: Frederic Weisbecker Date: Thu, 30 Apr 2009 20:05:25 +0000 (+0200) Subject: kill-the-BKL/reiserfs: release write lock on fs_changed() X-Git-Tag: firefly_0821_release~9833^2~3455^2~46 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f32049dc244f4d394c8faa161b4f13cb8c4f5c8c;p=firefly-linux-kernel-4.4.55.git kill-the-BKL/reiserfs: release write lock on fs_changed() fs_changed() is a macro used by reiserfs to check whether its tree has been rebalanced. It has been designed to check parallel changes on the tree after calling a sleeping function, which released the Bkl. fs_changed() also calls cond_resched(), so that if rescheduling is needed, we are in the best place to do that, since we check if the tree has changed just after (because of the bkl release on schedule()). Even if we are not anymore using the Bkl, we still want to release the lock while we reschedule, so that other waiters for the lock can acquire it safely, because of the following __fs_changed() check. [ Impact: release the reiserfs write lock when it is not needed ] Cc: Jeff Mahoney Cc: Chris Mason Cc: Alexander Beregalov Signed-off-by: Frederic Weisbecker --- diff --git a/include/linux/reiserfs_fs.h b/include/linux/reiserfs_fs.h index 4a2df57c8b1d..fa5dbf307c40 100644 --- a/include/linux/reiserfs_fs.h +++ b/include/linux/reiserfs_fs.h @@ -1333,7 +1333,13 @@ static inline loff_t max_reiserfs_offset(struct inode *inode) #define get_generation(s) atomic_read (&fs_generation(s)) #define FILESYSTEM_CHANGED_TB(tb) (get_generation((tb)->tb_sb) != (tb)->fs_gen) #define __fs_changed(gen,s) (gen != get_generation (s)) -#define fs_changed(gen,s) ({cond_resched(); __fs_changed(gen, s);}) +#define fs_changed(gen,s) \ +({ \ + reiserfs_write_unlock(s); \ + cond_resched(); \ + reiserfs_write_lock(s); \ + __fs_changed(gen, s); \ +}) /***************************************************************************/ /* FIXATE NODES */